All posts by phil stanton

CTC 3D Printer Upgrades

ctc i3 3d printerA reader has Kindly generated an article to help you with your CTC printer problems.

I will let you read it in his words….

by Ray J, Hereford, UK.

 At the start

Purchased a the CTC printer through Amazon, and arrived within 3 days.

First impressions

It is a very cost effective 3d printer, possibly not for someone who thinks that it will produce good results straight away.

The Menu system is clunky (with switch press model).

Followed build instructions on the supplied CD and youtube link supplied with the kit.

Modifications performed

Power Socket

Supplied un-switched power socket replaced with switched variant so that if things went wrong I could cut the power straight away.

This was mounted in a ABS box so that there was no exposed main power lines.

Bed Mounting

First major issue was that the y-axis bed (bottom rails) were not mounted rigidly to the z-axis upright.

This could cause everything to float when moving the printer.

First solution

My first solution was to print some U-shaped brackets to mount over the
bottom bars and screwed to a solid board. This worked to certain extent,
but the frame could still move about the centre upright.

I look for another solution.

Second solution

This involved purchasing a 1 metre length of M8 all-thread from B&Q, along with 12 OFF M8 nuts, and designing a clamp to grip the centre upright.

The clamp was printed first with the original fixing method used, so that the printer could be stripped to perform the rest of the modification.

The two bottom bars were removed from the end plates, and where these had been fitted 8mm holes were drilled through to allow the all-thread to pass through.

The all-thread was then cut to two lengths 440mm long, this allowed for the nuts to be fitted both sides of the end plates.

The all-thread was fitted starting from the back plate (bolted firmly), then the centre section with the clamp (M3 screws and nuts using the original plate holes bolted firmly with M8 nuts on the all-thread), and finally bolted firmly to the front plate.

This solution made the whole printer base more rigid and did not require the printer having to be bolted to a solid board.

y support stls

STL file – Y axis support 1.stl and Y axis support 2.stl

editors note : see end of post for stl download

Extruder Ducting:

With the PLA supplied with the printer my prints were very messy due to the material remaining hot.

Found a cooling duct on thingiverse that could use the existing fan
(didn’t require another fan).

cooling fan ctc 13
cooling duct from Thingiverse

Z-axis Top Support

When first tensioning the X-axis belt I noticed that the z-axis screws were being pulled in on the top mounts, and could cause wear grooves in the top mount.

Designing a top mount support with a bearing for the z-axis screws and grub screw to fix into the z-axis slide.

Two extra M3 mounting were added and required drilling the existing top mount to take the M3 screws and nuts.

Results were a little better but not much, and were not improved by
using flexible couplers, from the motors to the z-axis screws.

Amazon 698-2rs bearing – 19mm Outer diameter, 8mm Bore – 6mm wide High Carbon Steel (10pcs)

VLUU L200 / Samsung L200

Lefthand STL file – Mk1 LeftHand Z support.stl

Righthand STL file – Mk1 RightHand Z support.stl

z support stl

editors note : see end of post for download

Belt Tensioner:

My next observation was black plastic dust on top of the right z-axis
motor, and behind the front plate centre.

On closer investigation the plastic dust was from the idler pulley frames.

The centre bar that the pulley is attached to is D-shaped, therefore when tension is applied to the belt the flat of the D-shape eats at the plastic frame when rotated, and wears a slot.

This was also noticed at the end of medium print as the belts were not the same tension from the start of the print.

My solution was to redesign the idler frame to take the same D-shaped bar but have it mounted into bearings either side. When swapping with the existing frame note the orientation of the original frame.

Results were that the belts retained the same tension throughout the print.

This image is of the belt tensioner drawn in Autodesk 123D Beta.

cad idler frame

Bearings fitted

Amazon – 605zz – 14mm Outer diameter, 5mm Bore – 5mm wide High Carbon Steel

X axis idler
belt tensioner fitted to x-axis

STL file – Belt Tension with Bearing.stl

editors note : see end of post for download

The following modifications were made due to excessive Z-banding on
the prints.

Motor and Idler pulleys:

Machined aluminium geared pulleys were purchased from Amazon to reduce / remove backlash when motors / idlers changed direction. These items are secured using two grub screws. – Balitensen BAL-S2M17T5B6W-2 – S2M Pulley 17 teeth 5mm Bore – 6mm wide 3D printer part – (uk only…)

editors note – 17 tooth is not a usual pulley 16 or 20 tooth are more common – you will need to adjust the steps per mm – but the closest is the (#ad) 16 tooth  from Amazon

Bed Belt Mounting:

The standoff on the bed was done by the use of stacked wooden spacers that were not quite the right height so that y-axis belt did not run parallel. A standoff was designed to give the correct height with loops fitted for securing the belts.

cad bed belt mounting Autodesk 123D Beta

STL file – Y axis belt mount.stl

editors note : see end of post for download

Z-axis Screws:

The z-axis screws were replaced due to high amount of visible runout that could be seen with naked eye.

Alternative parts were sourced from Amazon along with a dial gauge indicator and stand for fine tuning the mechanical setup.

Amazon – HAWKUNG HK-221 – 300mm 8mm T8-2 Stainless Steel threaded rod lead screws with T8 nuts (2pcs)

Amazon- Flexible shaft coupling 5mm to 8mm (5pcs)

editors note : (#ad) dti and stand for fine tuning

Marlin Update:

NOTE: Read these instructions fully and understand before applying to the 3D printer.

With the modified threaded rod the printer would now move 10mm for a 1mm setting on the printer.

Thinking that I could change the stepper motor step setting and store them in the EEPROM on the controller board proved fruitless, as the EEPROM on the controller was not enabled.

(editors Note : this can be done even with the EEPROM disabled as you can add it to the slicer start up setting for each model – but it does have the disadvantage of not being set in the machine…)

This led to the only conclusion that the controller had to be updated to the Marlin firmware.

editor: new controller board (#ad) amazon

The controller board on my printer did not have a bootloader installed, so the first part of reprogramming the board was to install the bootloader.

Bootloader Installlation:

You will need the arduino ide : download it from here  Issue 1.8.5 is the one i used.

You need to add a bootloader driver to the arduino software.

Details for installing and the driver can be got from githubs 

usbasp programmer
usbasp programmer from Amazon with adapter

Either construct a 10 way to 6 way adapter using the information shown in the table or purchase a ready built one.

There are adapters listed on Amazon that come with a USBasp programmer.

USBasp 10 way to 6 way ISP adapter wiring table:

ISP 10 way on USBaspISP 6 way to 3D printerPin Name


Although a 10 way connector is fitted on the 3D printer controller board the two outer rows of pins are not part of the ISP. Fit the 6 way adapter in the centre of the 10 way socket using the keyway of the socket as a guide to which side is pin 1.

pin 1 for usbasp programmer connections ctc 3d printer

In the Arduino IDE preferences box tick the Show verbose output during upload, this will then give details of the programming process in the lower part of the Arduino window.

Click tools and selected the programmer as USBasp.

arduino programmer selection

Click tools and set the board to Anet V1.0 (Optiboot).

Click tools and then select Burn Bootloader.

Monitor the lower half of the Arduino window to ensure that programming was successful.

Marlin Firmware:

Location of Marlin firmware –
and download version

editors note : version 1.1.xxxx is a version that will fit comfortably into the  8 bit boards – version 2.xx is a very tight fit and may require a different bootloader to allow room for it…

Unzip the file and goto the
folder and copy the two header files into the \Marlin-1.1.x\Marlin

Open the Marlin.ino in the Arduino programming software, this should open all of the include files at the same time.

Select the Configuration.h tab in the Arduino software.

This is were the fun begins!

I change the following lines of the configuration file for my machine:

  • 132 – remove the \\ at the beginning of #DEFINE and in the speech marks enter the name of your printer you wish to display, in my case I used #define CUSTOM_MACHINE_NAME “CTC i3 Pro b”
  • 307 – change  #define TEMP_SENSOR_0 5
    to #defineTEMP_SENSOR_0 1
  • 312 – change  #define TEMP_SENSOR_BED 5
    to #defineTEMP_SENSOR_BED 1
  • 537 – change  #define X_MIN_ENDSTOP_INVERTING true
    to #define X_MIN_ENDSTOP_INVERTING false
  • 538 – change line from #define Y_MIN_ENDSTOP_INVERTING true
    to #define Y_MIN_ENDSTOP_INVERTING false
  • 539 – change  #define Z_MIN_ENDSTOP_INVERTING true
    to #define Z_MIN_ENDSTOP_INVERTING false
  • 543 – change  #define Z_MIN_PROBE_ENDSTOP_INVERTING true
    to #define Z_MIN_PROBE_ENDSTOP_INVERTING false
  • 617 – change  #define DEFAULT_AXIS_STEPS_PER_UNIT { 100, 100,400, 100 }
    to #define DEFAULT_AXIS_STEPS_PER_UNIT { 93.07, 92.77,400.55, 98.30}
  • 624 – change  #define DEFAULT_MAX_FEEDRATE { 400, 400, 8, 50}
    to #define DEFAULT_MAX_FEEDRATE { 50, 50, 10, 45 }
  • 632 – change #define DEFAULT_MAX_ACCELERATION { 2000, 2000,100, 10000 }
    to #define DEFAULT_MAX_ACCELERATION { 200, 200, 50, 500 }
  • 855 – change #define INVERT_X_DIR false
    to #define INVERT_X_DIR true
  • 886 – change  #define X_BED_SIZE 220
    to #define X_BED_SIZE 200
  • 887 – change #define Y_BED_SIZE 220
    to #define Y_BED_SIZE 200
  • 890 – change  #define X_MIN_POS -33
    to #define X_MIN_POS 0
  • 891 – change #define Y_MIN_POS -10
    to #define Y_MIN_POS 0
  • 895 – change #define Z_MAX_POS 240
    to #define Z_MAX_POS 180
  • 1157 – change  #define HOMING_FEEDRATE_XY (100*60)
    to #define HOMING_FEEDRATE_XY (50*60)

Connect a USB cable from the PC USB port to the controller board on the printer.

In the Tools menu ensure Anet V1.0 (Optiboot) is selected.

In the Tools menu select the port that the printer is on.

Switch on the printer and in the Arduino programming software click Upload, the progress of the programming should be seen in the lower half of the programming window.

Once programmed you should be greeted with a Marlin splash screen on the printer display and be ready to refine the stepper motor movements.

The menu screen should operate a lot smoother with press-and-hold of the push button switches.

For line 617 I used a toothpick and steel rule to measure the distance traveled in the x,y, and z over 100mm using the printer menu (NOTE: I had uploaded the default setting via the bootloader), using the formula of –

New Stepper setting = (Current Stepper Setting * 100mm) / Actual Distance Traveled in mm 

editors note : you will need to update the steps by using the m503 gcode with repetier communicating to the printer, to get the current settings…

Then use M92 [axis]calculated value to store the values

Where axis is either x,y, or z and the calculated value is from the formula above.

For example if the calculated steps were 96.28 for the x axis you would type M92 X96.28 and press enter…

I could refine the stepper motor to produce a more accurate print.


The prints were very much improved with the modifications performed. There is very little z-axis banding (0.1mm) so the effects are hardly noticeable.

The images show the print of robot from thingiverse (and also available the first time you run Cura). The robot on the left is with the original setting and on the right is will all the modification to the printer.

before and after robot

The results were more impressive with a larger print, in this case pencil holder of the terminator head.


I like all the mods that Ray has done to his printer.

i like the idea of using the steel ruler and cocktail sitck ( toothpick) to measure the distance travelled in one direction.

it could be carried out with an open verier caliper and hte axis pushing on the pin to close it for slightly increased accuracy…

with the USBasp programmer – most now come with the adapter – just make sure you get it in the right position in the center of hte connector.

I am impressed with the work he has carried out to take a cost effective printer from something that didn’t print very good results at all to something that is a very capable machine and his knowledge of his printer will allow him to work within the limitations of his printer.

Thank you for the write up Ray.

and he has kindly supplied the stl files for you to print

download zip files for ctc 3d printer stl upgrades

If anyone has any comments or wants to know more about  the CTC 3d printer upgrades then please leave a comment below…

How Large Can you build a 3D Printer

small printer to large transformation
Icons made by Freepik from

A lot of people look at the small volume of the desktop 3d printers and dream of designing a huge machine.

What limits the size of a 3d printer: mechanical components , complexity and costs are the three main limitations for the size of a 3d printer.

In theory there are no limits to the size of a 3d printer, but practically there are a few — let’s have a look at some of them…

What do we have right now

Your typical home desktop 3d printer has a volume of 20cm X 20cm X20cm for the x,y,z sizes.

This equates to 20x20x20 cm^3 = 8000cm^3

I know i have dreamt of building a huge , and i mean a huge 3d printer…

One that no one else has thought of building….

The stepper motors can be just the same….

As can the electronics….


And it will print chairs and tables with the same resolution as what i have now…

Ok…back out of dream land let’s look at some of the large printers around now and see what their specs are…

What are large format printer

So you want to print big huh…

Well you could easily go up to the Tronxy X5st with a build volume of 500 X 500 X 500 for about $700 – but that is not that much bigger…

Or the MODIX BIG-120X v3 with a build volume of 1200 X 600 X 640 for $6500, still not big enough…

How about the THE BOX from BLB industries a massive 1500 X 1100 X 1500 for a bargain price of $50,000 ( 2020 prices).

Mechanical limits

Your little desktop 3d printer with a build volume of 8000cm^3 uses 8mm straight rods over that span.

And you can bet there will be a little sag in the center.

Now double the width and that deflection becomes very serious with the weight of the printhead.

So you thicken up the rods to 2X the diameter – so that’s now 16mm diameter rods.

beam sag

The frame needs a bit more bracing with the weight increase.

And the belt is twice the length – you know how difficult it is to tension that standard belt – now you want it twice that length….

More stresses on the frame sides…..

The bed is now twice the width, so double sized. the weight goes up so the speed you can throw it around comes down…unless you uprate the motors and electronics….

And if you decide to increase the y axis then the bed is four times the size and weight …

Imagine trying to get that bed flat to within 40um over that distance and support it underneath…they struggle enough with the standard bed never mind one 4X the size…

And double the height – getting rods that are straight over that distance and increasing the leadscrews diameter….

And ideally an enclosure to keep the temperature stable to reduce the warping of the models…

So all around the mechanicals have to increase to keep the accuracy and that is only going twice the size…

Imagine 5X the size.

Besides not fitting onto your desk, the shear bulk of the mechanicals is getting so large that it is time to look for a different way…

For me it is individual sections, so maybe robot arms with an overlap – controlled from a central processor reducing the likelyhood of arm crash.

This way the different sections could be printed at once rather than sequentially…reducing the timescale of the large print size.

Electronic limits

Upsizing your printer may mean upgrading the size of your steppers – so upgrading your stepper drivers.

And you will need the stepper to get to the other side in almost the same time as now – so a massive increase in the speed and getting all that mechanics moving….

Again an increase in stepper motor size….

You will need an increase in the processing speed – so out goes your faithful old arduino…

Your power supply – on the limit for the old Anet a8 would be one part which now is huge – so power usage becomes a significant percentage of the costs.

Along with volume of printing material…

Are the slicers up to it

To 3d print a model you need to slice it and create a gcode file.

So let’s take a 25mm cube and slice it with 0.3mm slices – the time according to cura would be about 20 mins at about 60mm/s print rate

So keeping the speed setting the same lets double the size to 50mm all round.

The time has gone out to 102 minutes…..

To get back to the 20 minutes we need to increase the speed to about…well the slicers are internally limited in the software and won’t allow me to carry on increasing the print speed so i can’t get it below 82 mins

And double again to 100mm cubed the time has gone out to 7 hours and 51 mins (471 mins), even at the higher speed…

100mm box

So you can see that even a fourfold increase in size and a massive increase in speed the timing has gone out by 22 times…

The other way is to increase the nozzle size and then increase the layer thickness.

But if you want fine detail on the outside then you need the precision nozzle.

Maybe this is something they can look at in the future – printing on surfaces rather than printing the whole model, so 3d printers become surface decorators.

With this you maybe able to have the large layer heights and then finish off with a finishing printer.

 Is there any future for very large printers

As can be seen from the figures above – to get to a meter cubed you are looking at a very serious printer – industrial – enclosed and heated to keep it stable – very heavy mechanically to get the precision.

Will they go up much from this and get the precision.

I very much doubt that they are cost effective enough for a manufacturer to try.

The time taken to print such a volume must be huge, it is getting into the territory of cnc timing – so decisions will be made whether to remove material (CNC) or use additive manufacturing (3d printing)…

With the idea of the multi arm printers – you are adding a lot of cost and complexity, it would be unlikely that home users would have access to this sort of tech for a cheap price.

The same with the finishing printer.

Maybe the large layer height bulk printer, but the finishing printer would almost have the agility of a robot arm to get into all of the nooks and crannies.

So there is a limit of build size versus cost and builders of 3d printers are finding this whenever they build a large volume printer.

If you can sacrifice resolution then you can build larger, but if you want the really small feature size then you will have to put up with printers being about the size stay are at the moment until a massive breakthrough in tech happens.

BigRep / CC BY

You might find large fast printers at 3d print service centers, along with metal printers.

But for printing , and scanning, large objects on a fixed bed i feel that the problems will outweigh the benefits for a while to come…


Custom Start G-code : Is It Worth Changing 

Custom G-code snippet

When you load your Gcode into your printer, it will carry out exactly the commands it is told. Are the default ones the best for your printer…

Why customize the start g-code: Your 3d printer will do exactly what G-codes you tell it to do. So with a bit of careful programming you can optimize your start G-code with no ooze and custom heating.

Why change the start g-code

My 3d printing days go back to the old version of cura, when the version was a lot higher than it is now….(

Once you loaded up a model…set up how you wanted it to print…what you want it printed with…you pressed slice, and it popped out a file that contained the start commands and the stop commands.

Loading this onto an SD card and putting it into your 3d printer, it would happily heat up sensibly, move to the start position sensibly and then start printing.

As slicers have progressed it appears that less thought is put into the start code, almost having it as an afterthought.

Most slicers now place the print nozzle at the printing height before moving onto the bed, or heat both the bed and nozzle up at the same time.

I did try briefly in the past to add custom G-code but it normally just ignored it.

But i revisited it recently after trying out prusaslicer and it trying to crash my machine into one of my bed screws at the start….

What can be done

Once you start looking into what you can change in G-code you will be amazed and perhaps a little afraid to have a go.

But once you start and find that you can control your printer at its lowest level you feel in control.

The start code for most slicers now consists of heat the bed, heat the nozzle, zero the axes, move to the initial layer height, go to the first position and start printing.

Some, as i said above , even switch both bed and nozzle on at the same time, trying to overload your power supply for the length of time they are both on.

The old cura was a lot more gentle with the printer.

Zeroing the axes, moving the printhead up 10mm,heating the bed, heating the nozzle and moving to the start position all in one smooth movement.

This code had the advantage of missing any screwheads in the corners of the bed.

If you looked into it you could sit down manually and write your own g-code for your model using the special strings available and then process it through your favorite slicer.

But why would you- the slicer can do the heavy lifting, you just want to treat your printer with respect at the start and prevent damaging your nozzle as it moves to the start position for printing.

My safe routine

So instead of the standard start G-code trying to break my nozzle off i decided to create a similar routine to the original cura.

But even better, as i got fed up of the ‘snotty nose’ initial ooze and pulling off the filament at startup to reduce the risk of it not sticking i decided to have a look at this as well.

Using the prusaslicer, the startup process i decided on is :

  •  Heat the bed
  • Heat the nozzle to a ‘safe’ temp (160C)
  • Start with no fan
  • Zero the Axes
  • Move z axis up 10mm
  • Move the printhead over the bed
  • Go to the first layer height
  • Heat the nozzle the rest of the way
  • And  start printing.

My first few attempts didn’t end up doing what i wanted, but i persevered and found that using the special placeholders over rode the standard coding.

I used the Marlin g-code command reference to find what i wanted to do.

There are commands to start the heating process and then you can go off and do other things while it is still heating (M104- nozzle heating), or you can start the heating and wait till it is finished to carry on( M109 nozzle heating and wait).

And there is a host of other commands.

My Custom Start G-code

So my list of G-codes for the prusaslicer ended up as :

M190 S[first_layer_bed_temperature]; heat the bed and wait
M109 S160 ; heat the nozzle to a non drip temp
G21; set the system to metric
G90 ; with absolute positioning
M82; set the extruder to absolute
M107; start with the fan off
G28 X0 Y0 ; zero the x and y axes
G28 Z0 ; zero the z axis
G1 Z10.0 F2400.00 ; move the gantry up 10mm to clear any obstructions
G92 E0; zero the extruder
G1 X15.0 Y15.0 ; move the nozzle over the bed
G1 Z[first_layer_height] ; move the nozzle down to the start height
M109 S[first_layer_temperature] ; get the nozzle up to temperature
M117 let's Print…; put on the screen a messageCustom G-code snippet

Did it do what i wanted

The standard heating of the bed first before loading the power supply with anything else did work, i maybe will try starting the bed running and then zero the axes and all the other setup before going back to wait for the bed to finish. – i will update if it seems to work well and not drop the power supply volts on my anet A8 clone.

Setting the nozzle to a safe temp of 160C does get the filament soft but not oozing, this is for pla but may also work for ABS – as yet untried.

Moving the printhead up to miss everything – that worked well.

And again moving the nozzle over the bed – i had to adjust it a bit as the home position is off the bed rather than the corner of the bed.

Moving the nozzle back down shows me whether it will collide with the bed – it shouldn’t if the bed is leveled correctly.

And finishing the heating before printing, again works well with no ooze as the nozzle is so close to the bed.

I did try printing the skirt while heating the nozzle up, but as the filament was not liquid enough to be extruded then it failed while trying to feed the filament…not a good move.

And yes with the two special placeholders it prevented the slicer from putting its code over the top and messing things up.

Will this work with other slicers – yes

You may have to change the placeholder text

Cura has {material_print_temperature_layer_0} as the first layer nozzle temp

And {material_bed_temperature} for the bed temperature.

So those will need changing in the routine above.

But everything else is standard G-code.

In Simplify3d they call it custom scripting – but as i don’t own a copy then….the support area is your best bet i’m afraid.

here is a list of prusa and slic3r placeholders

and the cura ones are here

Advanced start G-code

What else could be added

Bed leveling – once i have my other machine up and running again i will be adding this and seeing if it really does help.

Linear advance – i want to investigate this as it does improve your overall printing.

Within prusaslicer and slic3r there is a section on conditional programming, so you can have your slicer make decisions on your G-code.

So if you always want your second layer temperature to drop a few degrees you can add this to your custom start code rather than setting it up in the slicer.

But be warned that the slic3r and prusaslicer conditional code uses different commands – so once you start getting into that level then it is best to stay with one slicer.

But with the conditional coding you can setup temperature towers for a specific model – changing the nozzle temp at certain heights.

You could run a speed test to see where you start to skip steps in the x and y  axes.

Thee is a host of things you could investigate, but start with the custom G-code to control your machine how you want it to startup and move forward from there.

I hope that this has given you the confidence to have a go at changing your start code – even if it is only changing the message on the lcd (M117)…it just makes the printer yours…..

Most stop codes are ok, they will move the print nozzle up a bit or home the x axis and switch off the heaters. But again you could customize this – but make sure you don’t knock off your model…

 How to Apply Kapton Tape to Your 3d Printer Bed

polyimide tape on bed

Do you want a smooth bottom to your prints, whether they are PLA or ABS or TPU. Well it is worth finding out how to apply Kapton tape tape to your print bed to achieve this.

Applying kapton tape to your 3d printer bed: Using a high temperature covering on your bed to allow your prints to stick will help in two ways – it protects the bed surface and gives you a smooth bottom to your print.

Applying Kapton tape to your printer build plate

Kapton tape or polyimide tape as it is more generically known (Kapton is a trade name of DuPont) is a high temperature tape, mainly now used in the electronics industry.

You have seen flexible pcbs…well they are made out of polyimide with copper tracks on them. You can solder parts to these as well, that is the sort of heat this material can take…

Using it to cover the print bed will allow your prints to stick to the surface of the tape and make them adhere while printing and when cold can help remove them.

Remove all the old surface adhesive

To start this process you need to get rid of the old surface coating .

What i am doing is replacing the surface on my aluminum build plate.

I know a lot of you have gone to a glass plate – and the process is the same.

So with IPA, or other solvent remover get rid of all of the old coating and adhesive.

You have probably dug into the old coating when trying to get prints off the bed—i know i have, and cussed a bit when doing it…

You try and stick it back down, but it never really sticks and gets caught in the first layer…

Once the print bed is clean

Once all the old adhesive has been removed then use a final wipe of IPA to get rid of any grease from the fingers or residue left from adhesive removers.

Plenty of water and soap

Depending on what you are like with putting screen protectors on your phone you may be able to get away with not doing this step, but most of us need to do this.

Get a spray bottle with water and a bit of dish soap – it can be cold water.

Making sure that you are not going to get anything wet that shouldn’t – and make sure your printer is off if you are working on it.

Spray the water liberally onto the surface.

Different widths of Kapton tape

There are different widths of polyimide tape and different approaches for applying it.

I have 50mm width ( 2 in) and wouldn’t go under that width, but you can go up from that to over 200mm (7.8 in).

Why the difference….well you can cover the bed in one piece rather than strips.

But before you rush out and buy the wider one, think about how you use your printer….

Do you print mainly small items, or are they large and cover the whole bed.

If they are small then it maybe worth going for the strips….

My reasoning is that i can replace a strip and the rest of the bed is fine, if i use the whole bed in one i have to replace the whole surface at once….

It probably makes no difference in the end, but i dislike wasting things…

But back to the now drying bed….

Cut a strip longer than the bed

Decide whether you want to go side to side or front to back.

My preference is front to back as i don’t remove the bed.

With the bed covered in the water and soap spray – make sure you smooth it over with your hand to ensure all over coverage.

Any parts not covered in the spray will allow the tape to stick to the bed immediately – this is not what we want.

Cut a piece to the right size plus 50mm or so (2 in) – this way you don’t have to position it exactly.

Make sure the sticky side does not touch anything, picking up any dirt or dust as this will make an impression in the bottom of your prints….

Lay it onto the bed in approximately the right position.

If there is enough water the tape will be able to be repositioned by hand – you will be able to slide it around.

If not it will attempt to grip – you can remove it easily at this point and spray more water onto the bed surface and try again.

Right to the edges

In the corners of the bed are adjusters.

Do you cover them or not – well i suppose it depends on whether you

Kapton tape and ipa need to get to them and plan on printing to the edge of the bed.

But remember if you are using 50mm width tap – four strips of this are 200mm and if your bed is 220mm then you will be adding a thin strip down one edge….

Or miss about 10mm either side – which is how i do mine.

This accounts for the adjuster screws…

So sliding the first piece towards the edge and getting it as parallel as you can by eye leave it there.

Spray some more water onto the bed and cut another strip to go next to this.

Lay the next strip onto the bed next to the first strip, you should be able to slide it to butt upto the edge of the first.

But don’t force it into the edge as this may cause a ridge and a thickness which will interfere with the first layer printing.

Spray, cut and place the other pieces onto the bed.

Squeegee the water out

Now comes the interesting bit – getting the water out from under the tap to make it stick to the bed surface.

Using a squeegee – an old credit card, screen protectors come with them, or even car body filler ( but not used ones with filler on please….).

You can use anything that will not scratch the surface and is relatively soft and flexible.

Start at the center of one piece and work towards the outsides.

Have some paper towel available to mop up the excess as it is squeezed out from under the tape.

At any point you see a large air bubble or crease appearing then stop and lift the tape.

Lift out the bubble or crease – spray with water and reposition.

It may take a time the first time you do this and you may get a few small bubbles left – but as with the screen protector you can chase them around to one place and towards the edge of the bed.

Do this for all the strips.

Heating the bed for the first time

After squeegeeing we need to make sure the last traces of moisture are gone before printing on the surface.

So now reinstall the bed surface if it was removed from the printer.

Make sure all the excess moisture has been removed from around the edge .

Some people trim it to fit exactly to the bed – it all depends on the type of person you are.

Personally i tend to leave the edges overhanging as they are useful when you need to remove it in the future.

As long as they are not going to interfere with the movement of the bed – or anything else with the printer then what’s the problem.

If anything i wrap them down the sides of the bed to reduce heat loss from there…

So now switch on the printer and selecting the bed temperature heat it up to about 70C.

And wait…….

Go have a cup of coffee and leave it for about an hour.

What you will come back to will horrify you – all those bubbles.

That’s where in the last stage if you get almost all the moisture out from under the tape it lessens the impact of this stage.

With the squeegee start at the center of the strips again and move any air bubbles out towards the edges. again with it in strips it is easier to get rid of the air bubbles.

Group them together to make larger bubbles.

If you cannot get these to the sides of the tape you can pop with a very sharp pin and force the air out (smallest hole you can so only just pierce the tape – a lot won’t like that stage but it does work if you can’t move the air out to the sides.

And you should now have a bed surface covered in Kapton tape.

Preparing for printing

So if you are going to print ABS, then you need to cover this surface with the ABS juice ( acetone and bits of ABS dissolved).

Or spray on hairspray to make it adhere better.

Or if it is PLA or TPU you can try it bare.

Sometimes the PLA has trouble sticking to the polyimide, if that is the case a little hairspray ( when the bed is cold) will help it adhere.

Cleaning the surface of the tape with IPA will remove any grease and again help with adhesion.

As will increasing the flow rate of the first layer – but watch out for elephants foot.

Once you see the shine you get when you take the print off the bed it will make you smile and think you never want to use a different surface again…

Until you cannot get your prints to stick and…..

Removing your prints

Once you have printed your model you will be eager to remove it.

I don’t blame you, you are excited to see what it looks like.

But be patient.

Make sure any item you use to lever up underneath your model doesn’t have any sharp corners, these can dig into the surface covering and rip it.

Just moving under the base a little and then using the scraper as a lever can lift a lot of the model up.

What i find is if this happens go around the other sides and do the same rather than just lifting the print from only one side helps preserve the bed coating.

Abs still warping

If when you print abs you still find it warping – especially on the corners try using prusaslicer or slic3r to add mouse ears on the first layer.

You could even  go for a skirt that has a height to prevent draughts from around the model. This is something i will try and report back on once i have an enclosure built.

Printing PLA onto polyimide tape

I have found it very hit and miss having PLA stick to the Kapton tape.

Even with the bed heated to 50 or 60C it still just drags the initial

adding blue painters tape over the toplump around.

You almost want to extrude a bit of filament then stop the print head and press it onto the bed to anchor it before starting your print.

This is something i will try and remember to look into, once i get the hang of changing the gcode at the start of the print.

But the finish you can get – especially if it not over any of the joints in the tape is mirror like and worth the hassle.

It is almost worth printing the bottom as the finish surface in some instances.

I now have started adding blue painters tape over the top of the kapton tape to guarantee the prints stick.

If i was good i could have a strip of blue tape where the model start printing on the brim and the main model on the kapton tape…..something i could experiment with…

Well i hope you do try using the Kapton tape for a surface finish.

Let me know in the comments whether you have a different method to apply it and i will try it.

What else can you use kapton tape for

As you use the cooling fan to cool the extruded filament you also have a chance of cooling the hotend block.

Doing this will cause the heater to be used more often than it should be adding stress to your power supply.

Covering the hotend block in kapton tape will give it at least one level of insulation – the better is to use the cotton insulation – which again is covered in kapton tape to secure it.

This way you will find that when you activate your fan – especially if you go straight for 100% – it does not thermally shock the hotend block.

Can you repair the surface

If you do happen to dig into the surface then the chances are high that you will rip a piece out of the tape.

Can you repair it.

You can try to stick it back down or you can but a larger area out of the tap and splice a piece in but the next time you print over the splice it will pull off again.

So if you start to rip it up then it is time to replace it.

This is where using the strips can win over the one piece – you just replace the strip that is damaged.

I have a glass plate i don’t need kapton tape

I know that the glass plate is a smooth surface, but if your print sticks too well then you may have another problem i see reported al over the web.

That of the print ripping a piece out of the surface of your glass plate.

Then this needs replacing.

If you cover it in kapton tape at least you have another interface to take the pressure off the glass surface and prolong its life.

Which types of glass plate is this more likely to happen with – well anything that is hardened may become brittle to the point of fracturing.

Whereas softer glass this may not happen as readily.


Prusaslicer vs Cura : Is it worth moving

3d printer in action

I have now been operating 3d printers for a few years and have got used to creating models – or downloading- slicing and printing. But have recently become more and more frustrated with the Cura interface – so started looking elsewhere.

Knowing that Prusa did their own slicer – originally a slic3r variant (which i have tried..recently)- they have now taken a version and gone their own way.

So is it easier to use, better, more workable, faster, more accurate that cura…let’s find out shall we….

Why a 3d slicer is necessary for 3d printing: A slicer is necessary for 3d printing due to the fact that a 3d printer needs coordinates to send the print head to for it to lay down the molten filament to create the model in 3d from your cad model.

When i started my journey in 3d printing Josef Prusa was making the Prusa i3 mk2, which i eyed enviously at the time.

Not willing to spend that much i settled on a prusa clone from china, which came bundled with cura – the slicing software.
The cura logo

We are talking version 15.xx of cura…the very basic one – but still a very good introduction to slicers…

Following the development of the Cura slicer and their versioning was interesting…now on version 4.xx…this all makes sense.

But version 15 had enough for me to start creating models on my printers.

It was absolutely fantastic.

But i am now looking at the newer versions of cura and seeing all of the parameters you can change under the expert settings and thinking – do i spend more time with the slicer than creating the model or actually printing it.

So I started looking around at other slicers to see what they could offer…

I have looked at Kisslicer – i now use their cal model as a test.

I looked at slic3r, and found that prusa have taken a version and gone in their own direction.

I do like slic3r and may come back to it, but it seems a little less advanced now that the prusaslicer.

I did look briefly at simplify3d – but with a slicer costing more that the printer and the slow updates, reported all over the web then i will give this a miss at the moment.

So i thought i would concentrate on the Prusa slicer.

prusa slicer logo

If i was starting now – what would i advise people to start with – i reckon i would go with Prusaslicer or slic3r rather than cura.

Why…i think just a little less confusing and has more features easily accessible.

That being said, i have only worked with it for just over a week  -and have had a few issues.

This is the reason for this post.…to prevent others from having these issues and to set it up right from the start.

Why look at prusaslicer

Looking at what you can do with Cura, and i know that a lot of the features are now available in there.

I found that creating curved tops was always a problem.

example of stair casing in slicer

As you go up the curve, unless you had chosen a fine layer height then you started to get a coarse stepping at the top.

The other part is that when making things like the x and y belt tensioners – i had a couple snap due to the amount of infill i added, but didn’t want to add it al the way through the model.

Finding that slic3r had adaptive slicing and you could create a layer stack, not just a hard step for the layer change made me smile.

And as i say after finding that the prusaslicer had this option along with the variable fill – i had to give it a go…

First go with Prusaslicer

After using Kisslicer and the introduction wizard to setup the printer, i found the Prusaslicer a bit awkward.

I am sure it is supposed to have a wizard that starts when you first install it, so maybe i have installed and deleted it in the past, but nothing came up.

prusa slicer first view

I do like the fact that you get the four tabs open on startup, with slic3r you have to open them yourself.

I didn’t bother creating a new printer for my anet clone and used an i3 mk2 as a printer.

On slic3r when you add a model it appears in the center.

Ok, but i want to print it front left corner, and until i found that tick box in the file -preferences it would always snap back to the center…..

The Prusaslicer comes with that box unticked, but it is under configuration preferences if you want the model to stay in the center….

First impressions

Looking at it’s simpler interface from the ( to me ) now cluttered cura one, i felt that it was laid out better – similar to the old cura.

But with four individual panels it feels lighter and has more breathing space.

Loading up the Kisslicer model it appears in the center of the plater (their name for the bed).

But is easily dragged to the front corner (where i usually create my models).

The graphical interface is pretty good – with all the features having a mouse over tip to tell you what they do.

I like the feature of setting a face down on the print bed.

And the fact that it is very easy to cut the model into pieces.

Right clicking when you have selected the model brings up another menu with a host more features.

More Features menu

One of the features i was looking at was to add more infill in places where the model maybe more stressed and not everywhere.

Well this is accessed in the right click on the model menu.

If you add a modifier you then have a selection you can modify within the shape you pick.

These are box, cylinder,sphere and slab.

You can easily resize the modifier and placing it manually in the graphical window can be hilarious, or a pain.

add different infill prusaslicer

But help is at hand in the right hand pane with XYZ coordinates.

Clicking on each shows the arrow in the direction of movement.

I was a bit confused with these as they don’t seem to follow convention.

The Y axis going up and down, the x axis left to right and the z axis front to back.

So the x axis is the one in the right direction, the other two are hopefully just wrongly labeled.

But in the right hand pane if you now right click on the little gear you can add the modifier – in this case infill and set it to what you want – i went up to 60%.

And then reslice.

Using the lower slices view in the left pane you can drag the layers slider down to see the effect of adding more infill and make sure it is what you want.

I think this feature is fantastic – with the only problem, even in the more settings the only one i wanted to use was not there – temperature.

I will dig more to see if it is an easy way to create a temperature tower, but i can see that characterizing the printer can be accomplished using most of these parameters.

One more thing about the slider – don’t click on the little plus symbol unless you are ready to change filament.

I must have clicked on it accidentally as the first model i sliced to test it printed all the way up and stopped on the last layer and unloaded the filament- not an expected result…..

So i looked at the G-code in craftware, i thought the listing said M500 ( store settings in eeprom), but i was mistaken and it was M600 (filament change).

But where….

When you click on the little plus on the slider you get a color change created.

There is no callout for this, there is no obvious deletion (especially when it is the final layer), but setting the slider to the layer does give you the option to click on the little x and delete the color change ( about three hours later and an internet search…..) – this has been the only thing i have struggled with so far….

Another excellent feature – especially for any rounded top figures you want to print is adaptive layer editing.

Rounded tops more accurately

Early slicers allowed you to slice at a layer height, and only one layer height.

Now this is ok, with large layer heights giving you shorter print times and lower layer heights longer print times.

Or looked at another way – large layer heights a coarse finish and low layer heights a fine finish.

So what if you have a lot of straight sides that could be finished with the larger layer height and a rounded top that really needs the lower layer height.

In the past you would have to suffer extremely long print times just to get the finer finish at the top.

But more and more slicers are now adding a feature to allow you to have adaptable layer heights.

Not every printer can handle this, so it is worth testing yours – i can’t see why not as they are dumb machines that do what they are told ( well most of the time….).

At the top menu the last item on the right is the variable layer stack – this is only available when in model view (this confused me as i would have thought it would be in sliced view).

adaptive layering - more rounded

Once you click on the layers menu then you get a view to the right of the model of the layers.

Using the mouse ( left and right buttons) to increase and reduce layer heights at the different heights of the model you can reduce the stair stepping at the top of the rounded parts – zooming in can show what effect this has – as can seeing the change in color on screen.

And printing it out it does really reduce the large steps if you choose a fast print time for straight sides.

How easy is it

It has been relatively easy to transition over to the prusaslicer.

There have been a few hiccups, as you would expect – the layer change was the worst one so far.

But the added features and simple interface allows you to start to explore the features instantly.

I did set it to expert control settings as soon as i jumped into it, but maybe the advanced would have been better.

I did click on the simple and would find these too limiting, but anyone starting out would have the very basics to adjust and hopefully the model would be passable.

Overall impressions

I think i am a convert.

I will still use cura 15.xx as a fast chuck it on there and see , but maybe with time even that will stop.

Would i put all my eggs in one basket, i will still look at the different slicers to find what advantages and disadvantages there are.

But most people who want to print models don’t want a steep learning curve, they want the model printed now……

There are a lot who seeing the page for setting the parameters of the printer in terms of speed and acceleration and jerk who would have skipped back to cura.

I did wonder where i would find those and whether they could be used to tune the printer a bit more.

On the Anet a8 i found them under the control ->motion menu and noted those down.

It does work without you setting those up as it will rely on the printer not exceeding its operating parameters coded in to prevent damage.

I will be doing more work on this slicer and hopefully will be creating a series of tutorials showing what it can do.

I will go back to cura version 4.x and see if the same features are in there – if they are ten maybe i will create tutorials on both….

But i hope you will explore the features of prusaslicer and maybe the forerunner slic3r if you are starting to get a bit overwhelmed with the number of elements you can change within cura…

What are your views – what do you think of Cura, prusaslicer or slic3r – let me know in the comments below

Thanks for reading


How Does Your 3d Printer Know What to Print.

what does your 3d printer understand

Believe it or not your 3d printer is a dumb machine. It needs to be told exactly what to do and when to create those wonderful models you require from it.

So how does your 3d printer know what to print: The file you create with your slicer tells the 3d printer exactly what to do and when to do it. It contains commands to move the printhead and how much material – if any – to place on the build plate and the heat the bed and nozzle need to be kept at.

Your 3d printer contains mechanical parts – the stepper motors- which need telling what to do. You also have heaters which need to know what temperature to be at…

What tells your printer what to do 

Your 3d printer is a bit like the old paper printer in the respect that it needs another computer to tell it what to do.

You can think of your 3d printer in the respects of the paper printers.

how a slicer works

Think of a pile of paper sat next to the model you want to print.

If you could push the pile of paper into the model then each

piece of paper would have a slice of the model on it.

If these are printed out in the right order then what you get with your 3d printer is a finished model.

If they are not printed in the right order what you get is a mess of plastic….

What are slices

As shown above you can have a pile of paper the same height as the model to represent each individual layer of your model.

But you can change this – within reason- with the size of your 3d printers nozzle.

The larger the diameter of nozzle the thicker the slices can be.

So instead of paper think cardboard….

A lot less slices.

But with that comes a lot less detail.

So if you are printing a plain box with little detail, would you use the finest nozzle you can or the largest nozzle to get the job done quickly…

I know i would be using the largest nozzle…

As i said you can control the thickness of the slices, this is done in a slicer program on your computer.

What does the slicer do

A 3d printer slicer does the same job as those meat slicers in the butchers.

Place the model in where the lump of meat goes .

butchers meat slicer
by Flickr

Dial in how thick you want the meat ….

And slice it off layer by layer.

That’s where the analogy stops as the slicer has to recognize what is an outside layer.

How thick have you set the wall thickness to be and what infill do you want.

It is a pretty complex program which takes your model and cuts it up into slices and works out where to position the nozzle and how much filament to extrude at that time.

And when it is moving between printing areas to turn off the extrusion and move quickly to prevent oozing and start printing again.

As the inside of the mode is not seen it doesn’t have to be full of plastic, so can be printed with an infill of a certain percentage, just to support the structure as it grows upwards.

You can adjust this infill, right up to full, to allow the parts to be used mechanically.

To allow the material out of the nozzle it has to be heated up so that it becomes runny, but not overheated…

So the slicer tells the printer that the nozzle needs to be at this temperature and the printer adjusts the heater until it reaches it. The printer now controls the nozzle temperature until told to change it.

The same with the bed temperature to help the model stick to the buil platform.

Every little move, very little extrusion must be listed in a file to control the various parts of the printer correctly.

So the final push of the slice button may, on a complex model take a few minutes to create the file for your printer to create the model from the screen.

What is g-code

The file the slicer produces is in a format called g-code.

This was invented to control CNC machines – or even further back for manufacturing pcbs.

The pcb’s conductive layer is in effect a single slice of a model, and can be printed using conductive filament…..

As CNC can work in 3 dimensions this format was thought to be ideal for adopting for 3d printers.

There is a move to change the format to one which is more suitable, but the adoption is slow…

So…the g-code – what does it look like….

example of gcode

This just looks like a bunch of numbers with letters in front – and that in essence is g-code.

It tells the printer where to start and then how far to move in the x direction and y direction, how fast and how much material to extrude over that time.

Then at the end of the layer is tells the z axis to move up to the next layer.

And it follow this file step by step until is reaches the end.

Where it switches off the heaters for the extruder and bed, makes the stepper motors go silent and waits to print the next model.

What are the main codes in a g-code file

The file commands th printer to go through a process.

The first command usually is to home the printer (G28), so that it know where it’s printhead is.

Then it heats up the bed and then the nozzle( M140,M104 and M109).

It usually raises the nozzle and goes to the start point for printing(G0,G1).

And now goes through the move and extrude commands in the file.

Even for a simple 25mm square calibration piece you have thousands of commands, depending on the layer height.

How do you get the file to the printer

There are three main ways to get the g-code file to the 3d printer and they are :

  1. SD card
  2. Usb cable
  3. Octoprint

Copying the file onto an sd card and inserting it into the printers card slot allows you to select the file to print.

There can be issues with sd cards not being read– with the shaking that the 3d printer does and the card slot being on the casing can make the contacts intermittent and fail to read the next command, in which case the print fails.

This can happen at any height, but with the anet a8 it usually happens as the model grows in height and the slightly unstable frame rocks a bit more.

But it is normally a reliable method of file transfer and means you can power down your computer or use it for other things while printing without worry.

If you decide to use the usb then you need to make sure the computer does not go to sleep while printing.

Or update any software to make it reset – a common problem with windows….

It also means the computer needs to be located close to the printer  – not always convenient to use at the same time.

And you need to not overload and stop the usb from communicating as the printers are not overly intelligent and will crash with too many commands.

Alternatively you can add a raspberry pi with octoprint to control your printer.

You can communicate with it wirelessly – sending the file over for the model and then this is sent onto the printer.

You can get feedback on how the printer is doing, how much longer the print has to go and other information that means that you can locate the printer in a remote part of the house if desired.

And finally….

So you now know how your 3d printer takes the file from your slicer.

Where you have set the height of the slices and what the filament needs.

Which the slicer finds the paths of the model to create the outer skin and the infill.

In the background it is a very complex process, but on the surface one which is getting easier to use.

And hopefully in the future even easier, with the slicer embedded into the printer itself.

Then it will be download or create the model and select the quality and hit print….

At the moment you need a few more steps and to follow a workflow.

Getting used to going through a process will prevent you from making too many mistakes -we all make them don’t worry…..

And being happy with the newly created model from your printer is what this process is about.

Understanding a little more, when you see the g-code now it may not be all confusing as you start to see a pattern or use craftware to view the model before you print and see the holes and start to know what to alter to repair them.

If you have any questions about this process please leave them in the comments below and i wish you good printing.


My Filament is Not Coming Out : Why?

no filament out of the nozzle- find out why...

Filament problems with your 3d printer – find out what causes them and how to fix them.

It’s always the case – the print that matters – you have setup the printer and made sure everything is working – you go to print and even the perimeters are not printing  -now what…..

The filament is not coming out of my hotend : There are a few reasons that filament may not come out of your hotend: nozzle too close to the print bed, extruder not working, clogged throat or the filament not loaded correctly.

But all of these problems are solvable, once you sort out the main reason, in this article I take you through the possible causes of the filament not coming out of your nozzle and the solutions….

  1. Extruder motor not working
  2. Extruder gear not turning
  3. Extruder gear misaligned
  4. Not enough tension on filament
  5. Filament not loaded correctly
  6. Throat clogged
  7. Nozzle cold
  8. Nozzle jammed
  9. Nozzle height too low

Let’s have a look at each one, what you see and how to correct it.

Extruder problems

Extruder motor not turning

After you have determined that the printer doesn’t have any filament coming out of the nozzle, look at the extruder gear /shaft and see if it is turning.

If you cannot see these due to the fan obstructing them then hold the filament gently and you will feel it being tugged into the extruder.

And you will feel the motor stepping.

If you don’t feel the motor moving there can be two causes.

  1. The G-code has become corrupted and no extruder information is in there
  2. There is a problem with the motor driver, motor wiring or motor.

After halting the print you can examine the G-code to determine whether it is correct, it is always worth just checking the G-code to see what you are sending to your printer – i tend to use ideamaker or craftware ( my favorite as you see the G-code).

The printer may have just had a glitch and restarting it will print ok, but go through the rest of this article and make sure everything else is ok before restarting the print.

To test the motor use the manual movement menu to move the nozzle away from the bed.

Navigate to the extruder menu and retract a couple of mm and see the filament move – or at least try to ( but only if the nozzle is up to temperature – see below).

If the motor doesn’t move then you need to fault find on the motor system.

See my motor system fault finding article for more information.

But the basics are :

  • Check the wiring for open wires
  • Check the motor for open windings
  • Check the motor driver for correct operation

You can swap the extruder motor for the x motor ( if you know that is working correctly) to test for wiring and motor problems.

Remember to swap it back afterwards.

Extruder gear not turning

This is a commonish fault, where the grub screw works its way loose.

The motor is turning, but the gear is not turning – so no filament is being fed into the hotend.

Use the movement menu to move the extruder ( again if the hotend is up to temp) both forwards and backwards to make sure that the gear  rotates correctly.

Re tightening the grub screws fixes this.

Make sure one of the grub screws it located on the flat of the shaft –

tip for seeing whether the shaft and gear are turning in synch - add a linethis way it takes a lot more to have this fault.

One tip is to use an indelible pen to mark the gear and shaft to see if they are rotating together.

This way, when you carry out your routine maintenance ( you do do it don’t you) you can see at a glance that the gear is rotating with the shaft both on load and retraction.

Extruder gear misaligned

This fault is common when you build the printer.

You push the gear onto the shaft and tighten it

When you load the filament you don’t notice that the filament is not catching on the teeth, but on the shaft and cannot be fed into the hotend due to no force on the filament.

You can visually see this when you remove the cooling fan.

Repair is to loosen the gear and realign it with the friction wheel.

Check that when you load the filament you can feel the motor turning when you pull on it gently ( and a visual check is worth it)

Not enough tension on filament

This fault shows no flow of filament from the nozzle.

The filament is catching the teeth of the extruder gear.

There is no clicking of the extruder motor.

There is no grinding of the filament.

There are no marks when it is unloaded.

This would indicate that there is not enough tension on the filament and the gear is slipping over the filament.

To test that filament is coming out of the nozzle, making sure the nozzle is up to temperature, push on the lever to release all the tension and gently push down on the filament, forcing it out of the nozzle.

Correction is to increase the tension on the filament by adjustment of the screw on the spring for the pinch roller.

Filament not loaded correctly

This is another problem you come across when starting out.

Feeding the filament into the extruder and down to the hotend can be problematic.

Knowing whether it has entered the hole for the throat and has gone in far enough to reach the hot end without hitting an obstruction.

If you suspect this then mark it at the top of the extruder and withdraw it.

Measure the depth of the extruder and hotend to the nozzle and see it this measurement ties up with the mark on the filament.

If it is a lot short there maybe an obstruction in the throat or a misalignment of the liner to the nozzle – something that prevents the filament reaching the hotend and then coming out.

A thin wire or toothpick (preferred) can be carefully inserted into the throat – feeling for any obstructions – this is carried out after removal of the extruder motor.

Mark the toothpick and if necessary disassemble the hotend noting whether there is any obstruction at the height you measured.

Reassembly and readjustment of the z height will be necessary before you print again – so this one is a last resort if possible.

Hotend problems

Throat clogged

If your filament rises too far on retraction it can drag heat too far up the throat and on cooling the filament can start to cause a problem feeding the filament down.

If your hotend is too hot, the heat can rise through conduction melting the filament above the hotend causing a blockage – preventing the filament being fed through the nozzle.

You may hear a ticking as the extruder gear jumps on the filament, it is a regular tick….tick as the gear tries to feed the filament into the hotend.

To test for this – release the pressure on the pinch wheel and push gently onto the filament – forcing it down.

You will feel whether it is moving or not.

If it doesn’t move then try retracting it.

This is done with the hotend hot.

If it wont retract then it maybe jammed in the throat.

Removal of the extruder motor and lifting the extruder gear and pinch roller off the filament before cutting the filament and stripping down the hotend is the only way to cleat the blockage.

Make sure the nozzle is hot when you remove it as i have sheared one when trying to remove it full of filament.

You maybe able to force the filament down through the hotend to get it out.

This is one of worst faults as you need to reset the whole of the hot end and bed height, it all takes time.

Do check your retraction lengths and temperature you are running your material at.

Make sure there is adequate cooling at the extruder – put the fan back on….

Nozzle cold

If the extruder doesn’t start to click and the print starts to fail with no filament coming out, then flick your eyes up to the nozzle temperature before you abort the print.

If the temperature is below 180 degrees then there is a safety cutout where the software stops feeding the filament below that temperature.

This maybe due to a hotend heater failure or an intermittent connection.

With the movement you get on the hotend, unless the wires are secured the movement can cause a rapid failure at stressed points – like where the wire comes out of the heater.

This connection maybe made when the nozzle is on the bed, but open when the z height raises, causing a little confusion as to where the problem is.

A gentle tug on the wiring will determine whether it is secure into the heater or comes away easily.

Replacement of the heater cartridge or heatblock is the only course of action – making sure you secure the wires to reduce this in the future.

Replacement of the heatblock will mean that you have to check the bed clearance again….

Nozzle jammed

So with the above fault you were not able to withdraw the filament from the throat.

With this one you can.

But still pushing down on the filament, with the hotend hot nothing is coming out.

You may get the same ticking from the extruder as in the fault above.

Ok, so you now have a blocked nozzle.

Thee are two ways you can deal with this.

With the nozzle hot – replace it.

Or try a cold pull to remove the material from the nozzle and hopefully the debris.

To carry out a cold pull take the nozzle temp down to 100c with the filament still inserted.

Once it is there – release the tension on the pinch roller and give the filament a hard yank – but don’t damage your printer.

Hopefully the filament has come loose from the nozzle and reformed itself into the lining of the throat before it cools.

When it comes out it should look like the inside of the nozzle shape on the end.

Thee maybe little black bits on it – these could be burnt filament or other debris gone down into the hotend causing it to be jammed.

It maybe that the filament comes out but it doesn’t feel like all of it came out, to test this cut the end at 45 degrees and reinsert – if it doesn’t go all the way down then you have a piece stuck in the throat.

Using a drill smaller that the throat you could try to force the filament down to the hotend and try the cold pull again – or remove the nozzle and then force the filament down the throat.

Whichever way you do it – remember there maybe debris on the end that will cause a blockage again – so don’t just force it down and carry on printing…..

The easiest way is to carry stock of the common nozzles you use and replace it if it jams. They are cheap enough to carry a few in stock.

There are on the market nozzle cleaning kits.

These are made up of very thin steel wires used to force the filament out of the nozzle when it is jammed.

For me i wonder at the damage you can do the the brass nozzle ( which is very soft compared to the steel) waggling the pin around trying to clear the jam.

But really all you are doing is to move it to one side, waiting for it to clog the nozzle again- or partially clog it in a few minutes or hours…

Now you go back to printing with an unknown nozzle size and wonder why your prints are not as good as they used to be.

As you can tell I am not really a fan of these as they can do more damage than they fix.

If you take off the nozzle you can then clear it out from the rear without damaging the accurate exit hole.

Bed height

Nozzle too close to bed

This fault is one most beginners get , I still get it occasionally, but i know quickly what to do.

The first layer starts to print – you have spent hour s leveling the bed and it is perfect.

But no filament is coming out.

Then you hear the extruder gear clicking.

And you think you have a clogged nozzle .

So you abort the print – raise the nozzle and push the filament through.

Only to have it come out of the nozzle quite happily -dropping straight down.

This maybe a case where the blockage is the bed itself.

With the nozzle too low no filament can be forced onto the bed.

When you get a little more experience then you will be able to use the time your printers takes to print the perimeter lines to adjust the bed.

Knowing that a whole turn of the bed screws adjust the bed down 0.45mm to 0.5mm depending on whether you have 2.5mm or 3mm screws.

You know that there is quite an adjustment if you don’t see any filament come out, then you see the filament ooze around the nozzle and know that it will not stick to the bed.

You could try pinning it down with a scalpel to try to drag it off the nozzle, but 9 times out of 10 I halt the print and clean off the nozzle and give the bed screws half a turn to move the bed downwards – wondering why it has moved again.

Checking the z endstop tightness to see if that as caused this problem…

And Finally

I hope reading through this has helped sort out thing to try to clear the fact that the filament is not coming out of the nozzle.

Let me know if you find any more which can cause this and i will add it to the list.

Thanks for reading



 What is 3d Printing Workflow

3d printing workflow

 What is 3d printing workflow

How do you get from the concept to something in your hand with an fdm printer….

What is 3d printing workflow: 3d printing workflow is the method of taking a concept of what you want and turning it into a finished model that does what it is intended to do. 

Let’s break down the workflow into it’s what is actually happening – and this happens for each print you do, whether you follow these exact steps deliberately or just merge them in your head.

3d printing workflow

There are multiple steps within the workflow and these are broken down as :

  • Concept : what you want to create – be it a broken piece or a new design
  • 3d cad: design the article in 3d cad to suit the concept- taking into account 3d print design rules
  • Stl translation: translate the 3d cad file into a mesh file that is necessary for the slicer
  • Sliced: taking the mesh file and creating a layer file for the 3d pritner to be able to print
  • Gcode check: always worth examining the gcode to see if it will look anything like what you want.
  • Print: always a nervous time for the first layer but the exciting time to see the model grow
  • Post processing: removal of supports, stringing, if necessary holes enlargement painting.
  • Done: sit back and look at what you have created…..

let’s look at these in a little more detail.

Model concept

Something breaks, you find that you need a hanger for something,

board game piecesyou have an idea that will revolutionize the beer drinking world, a missing piece from a board game….

All of these will spark off a need to build something.

So you buy a 3d printer.

It may happen the other way around – that you get a 3d printer and print a few models, get disappointed with some of the results and put it into the corner.

But sooner or later you find something that sparks that ‘i have something that will make that…’

You now have something in your head you want to bring into reality.

The first thing to do is to sketch it down with pencil and paper.

Look at it, can you imagine it doing what you need it to do.

Does it look like what you imagined.

Turn the paper, redraw it from a different angle.

Happy, well we can now commit to drawing it in a computer

3d cad programs

To some, now is the scary bit.

3d cad drawing

But 3d cad programs have come a long way to helping the user.

Some of them have basic building blocks – square, cone, ball, and a few others .

With these simple shapes you can build up hugely complex models.

Or if you are more of an organic person there is software that starts out with a ball and you can pinch, extend, add blobs and mould to get the final model.

If you are used to cad programs at work – there will be similar ones – freecad, fusion 360, openscad or similar.

So you can create your model in the cloud or offline to the level of detail you want and the measurements you take.

You may need to come back to this later after actually printing it and adjust it slightly to make it fit – it is normal in industry to go through a few iterations or designs before the final model is accepted and this is what 3d printing excels at.

Stl file translation

To get the cad model into a form that your 3d printer knows what to do with takes a two stage process.

The above model from the cad program needs saving in a format that can be passed through a slicer – don’t worry this is explained below…

But slicers need models in a certain format.

So the cad programs can export the model as a mesh.

Think of the surface of the model, the skin being made up of triangles.

So a curve looked at through a magnifier would consist of loads of triangles rather than this smooth curve.

And all these triangles need to be the right way round for the model to be watertight – yep it means what it says – another word for it is manifold.

The model needs to have no gaps or meshes the wrong way round or the next process gets confused.

You can use a lot of the cad programs to see the meshes to check them or there are specific programs to check the model – like netfabb

The exported file is in the form of a stl file – yep those are the ones you download from places like thingiverse.

These are the files sent onto the final processing before getting to the physical model.

They are processed in programs called slicers….

3d Model slicers

To get the mesh models to print on a 3d printer you need to simplify what the outside or the surfaces are like.

The 3d printer is really a 2d printer that can be raised in height, so

3d printer slicer softwarealmost a 2.5d printer building it one layer at a time.

It can’t turn the extruder upside down to print things underneath, so it needs a process that formats the surfaces into layers.

Or slices…..

Hence the term slicer  – they convert your model into a number of slices that can be built up.

Understanding what slicer software can do, what you can change and what they have hidden is one of the keys to getting good 3d prints.

There are a few slicers out there, not all very user friendly and i hope in the future they will be built into the printer itself to make them easier to use…

We will see…

But in the meantime it can be one of the stumbling blocks for a 3d printing.

If we take one of the most common slicers, cura, and look at what you can adjust – currently ( april 2020) there are over 200 parameters in expert mode with everything turned on that you can adjust….

I don’t want to think of the number of permutations of changes you can make, but it will be in the billions.

This is one reason for quick and dirty prints, i keep an old version of cura ( all the old versions are still available) with it’s simple interface ( makes it a lot quicker to setup and get the file for printing as well)

I am also looking at another slicer with interest called slic3r, which prusa used to copy and add their own mods to, but they have now gone in their own direction and i will explore that one as well in the future.

But getting a slicer that works well with your printer makes your job here a lot easier.

This is the point where you are combining your cad with the material and the printer parameters.

You setup the materials, the rate of flow for the material, the layer height, the speed of the printer, and a few other settings.

Then you press slice, and it takes the model and creates a stack of 2d layers for the printer to understand.

This is the reason you get that characteristic ridged surface on the 3d printed model.

One thing i really would advise you to do is to check your gcode file ( this is the output of the slicer to be passed onto the 3d printer).

If you open the gcode in a program, you are not printing blind.

You can see what the printer will do, where it will start layers, where it will travel between printing parts, what it thinks is an inside surface and an outside face.

In small areas whether it will fill in the details or it will miss parts.

All of these can be sorted in the computer, within the limitations of the technology.

And there will be less failed prints and frustration…..

It is quicker and easier to make changes to the slicer now rather than waiting for the printer to finish…

Once the file has been checked and looks ok on the computer it is finally time to get it out into the world…

3d Printing

These have been around for a while now, they are getting better and easier to use.

The printer is in effect a 3 dimensional robot which lays down

3d printed cloth vase
cloth vase
by Sashko- thingiverse

material when commanded.

So the gcode file the slicer creates is the one that needs to be loaded into the printer for it to replicate the original model.

This can be done with a computer interface ( making sure the computer doesn’t go to sleep as printing times can be quite long ) or it can be transferred to a sd card ( always my preference)

I do smile when i read in forums that the print got to 90% and the computer decided to carry out an update to windows…..

One way around this is to put your internet connection on a metered connection and windows will always ask to update itself……

So you heat the hotend, insert the material you want the model in, select the file for the model and wait…..

The heat bed heats up, the hotend stabilises…and the nozzle moves towards the bed…..

And with its familiar dance across the print bed it starts to lay down material.

And questions start to arise in your head from memories past.

Will it stick to the build plate, did i level the bed enough, when was the last time i cleaned the bed, will i have another power cut…..

But fortunately in this case you have learned that to have the nozzle a little too close to the bed is better than too far away…

And you can cope with the little bit of squish to trim off after.

I always watch the first layer to gauge whether the model will stick.

And yes sometimes it does go wrong, but if you are there for the first layer then you can abort the print, clean the bed and start again.

Maybe even leveling the bed a little before stopping the print….

I do normally pop back to see how the model is going – i am fascinated with seeing it ‘grow’ from the print bed.

As the nozzle and the bed do their dance to create material in the right place to form what has been programmed.

And looking at the screen and seeing 100% with the nozzle lifted away and silent always puts a smile on my face.

And with a sigh i take the scraper and starting at a cornertry to remove the print from the bed.

And move forward to the next and final stage of the 3d printing workflow…

Post processing

Getting the model off the bed is not always an easy job…

I have seen numerous glass plates with chips out of them where the model has stuck and pulled a piece of glass form the plate.

Or in my case with the paper tape on the metal bed, i have ripped up the tape to remove the model from the bed, only to not be able to remove the tape from the model.

But with the model removed you can now hold it up, turn it  around – start to examine it .

Does it look like what you originally conceived, has your mind vision been translated into physical reality.

If it is something to replace a broken part, now is the moment of truth….

Does it fit…..

A lot of time you do need to fettle (technical term for filing, cutting and adjusting the size) things like hole sizes, depending on whether you left enough tolerance for the print.

This is where you will learn what your printer is capable of at the moment and can go through adjustments in the cad program and forward in the workflow ( so reducing the amount of material extruded ) to get a piece you know the size of.

Do you want a smooth finish, does it need a little more curvature.

All these post processing procedures can be now carried out on your model.

Smoother finishes can be material off or filling in the layer lines.

Then spraying with a finish.

More curvature can be change the cad file, or in the case of pla…

Place in a up of hot water – leave for a few seconds – remove and gently adjust  -hold until cool.

But now to have something that a little time ago was just a thought in your head, or a broken article that now has a new lease of life.

With a file that can be shared with everyone around the world to make.

For me it is one of the more magical moments.

I have made a few pieces for childrens doors, and the looks you get when they see it for the first time is really priceless.

Making lithophane lamps, which portray their favourite characters when lit up.

Or giving to grandparents an image of the grandkids when lit from behind.


There are endless possibilities to create and repair things with a 3d printer.

Once you have got bitten with the bug you may never stop.

And you may not stop at one printer.

This is mainly due to the time it takes to create the prints….

So one becomes two….two become three… know how it is…..

But this workflow is something you get used to.

It looks a lot, but  lot of the time you will download the model in stl format, so shortening the workflow.

It relly is worth checking the model for manifold, and then after creating the gcode to reduce the disappointment.

And keeping your printer in good working condition, rather than waiting for something to break before repairing it.

You can’t cover everything and they will go wrong or need parts replaced.

So keeping spares in stock reduces the frustration of not being able to print now….

But i hope this has shown you a little of the workflow of 3d printing and has inspired you to give it a go…..

What ….no 3d printer….are you going to let a little thing like that stop you…..

Nowadays you can design the 3d model and order one online from 3d printing shops.

The model appears in a few days through the post.

You can then see how close you are to your vision.

So no excuses and it might make you take up the hobby…..

Thanks for reading


Institute of 3D Printing : Is the 3d printing world ready for training?

So you bought yourself a 3d printer ….

Anet 3d Printer

It’s sitting on the table over there looking at you…

Waiting to be used….

Now you have browsed through thingiverse ( if its up) or Yeggi to find a 3d model you really like.

Downloaded it – seen the proof that it prints online….

So you give it a go….

That blob on your build plate looks nothing like the model….

What the ….

Where do you start to find out what you now do to create what you want…

Ah…Facebook- plenty of experts on there….

And you get plenty of advice

‘Try tweaking the filament size.

‘What about your belts

‘Turn on coasting

‘Turn off coasting

‘Loosen your belts….

You know the routine….

What do you do.

Who do you turn to for sound advice .

Someone who has years of solid experience.

Someone who has put together some 3d printing training…

Introducing the institute of 3d printing

Ed Tyson

Created by Ed Tyson.

Who some may recognize as the starting Rigid ink – selling filament.

Also the creator of the first 3d printing summit in Dec 2019.

Institute of 3D Printing

He has now opened a learning portal where you can find out about the wonderful hobby you have started.

What’s inside

Once you sign up and log in then you are presented with a dashboard showing the courses across the top as a menu.

Don’t skip the safety training, thinking you know it all .

We all know it, but it is worth just reviewing it again.

Once that is done then jump into the core course.

You get 6 modules within this course .

With the first two open straight away and the others following along at weekly intervals.

Then there is the advanced slicer mastery.

Taking on the three main slicers of the day.

Cura, Prusaslicer and Simplify 3d.

Cura Slicer

Go in depth into each setting.

Get to know simplify 3d before you put your hand into your pocket

and buy it.

Do you like the interface, do you think you will get on with it.


See what your tutor thinks of it as she takes you through what each

element does and how it affects your prints.

Get the same stl files to slice and print – see what differs between what they get and what you do.

See you progress across the bottom as you complete each module.

Simplify 3d slicer

If you need faster help then there is the ‘ask an expert’ – where you can ask an expert for help on specific printing problems.

Show off your finished print – show the difference between what you started with and what you ended up with and how you got there.

Find the friendly community of like minded 3d printerers who want to improve their prints.

Take a deep dive into the monthly masterclasses.

New topics and more indepth step by step methods of getting there.

Or download the podcasts, to listen to while traveling to work, on your lunchbreak or just a bit of downtime.

Get to know how the experts do it and their tips – put these into action and see your results improve.

Download the free resources – the ultimate beginners guide to 3d printing and the ultimate 3d print quality troubleshooting guide.

Both very valuable resources.

And finally sign up for the monthly newsletter.

This will keep you up todate with any news, success stories , what’s happening – so you don’t miss out on anything within the institute.

And that about covers it.

But i hope you will agree that there is a tremendous amount of information available within the institute.

 What did i think

Ed sent me an offer for a two week free trial.

So i thought about it and decided to sign up.

The clean interface with the drop down menu give you quick access to the courses you want to go to.

Going through the safety training video reminded me to start a maintenance log.

Ad to check that all the connections were still tight.

Would i get a fireball extinguisher , i tend not to leave the printer unattended so not at the moment.

Watching Adam go through the basics of the 3d printer and then onto bed leveling was interesting.

A good explanation of 3 point and 4 point leveling – reasons for and against.

There were stl’s to download and try out for bed leveling – this way you can go back to them and ask questions knowing that they know what you are printing.

There were only a couple of extra lessons within there at the time i joined and i hope that there will be many more very quickly.

Each of the lessons with downloadable resources were about 20 mins long.

So you won’t be having ‘that look’ as you come back into the family room.

Going through the advanced slicers course i chose Cura to start with – as that is the one i use most often.

Ed has chosen to focus on three of the main ones – cura, prusaslicer and simplify 3d.

I am sure as requests come in there maybe more added to the list…

Susan, you tutor takes you through each of the menus and what they mean to your prints.

I did pick up a few tips to improve my printing – so thank you Ed, Susan and the team.

Even if you don’t use the other slicers it is worth going through the training to see what they are like – especially simplify 3d.

If you like what you see then you may be able to justify it a bit more.

As they go through lessons you will pick up tips on how to change the quality of your prints.

Again there were a limited number of modules and they are still releasing them.

I don’t remember going through the prusaslicer training or it wasn’t available but i expect it will be up to the high standard of the other two.

The rigid ink mascot does get moved around the bed a lot within these videos – but it is one that can be used as a test piece.

Shame i didn’t see a download for it.

I didn’t try the ask an expert, but seeing who the experts are – the trainers, i can feel assured that the answers would have been correct or at least would move me a lot closer to getting my print quality where i want it.

And you can go back, with the continuity of them knowing what you have been doing…

The podcast wasn’t available, but after watching the 3d printing summit late last year I am certain that the visitors or the information given will be of high value and worth listening to.

Who would I recommend it for

3d printing is still in it’s infancy.

I cannot go on a 3d printing design course ( i may be proven wrong).

Learning about the rules of design for 3d printing- it is normally left to the individual to find the rules and apply them.

I did find a few years ago a cad program dedicated for 3d printing, but it was a paid for program and soon disappeared, unfortunately.

In the meantime learning about 3d printing consists of reading the help from the slicer programs and trying to interpret what they mean.

Sorting out whether the printing problem you have is due to the slicer or a hardware problem is again down to you – or asking the FB experts…

Now what you have is someone who has put together a learning platform for beginners through to experts.

Where they can all ask an expert and know that the experts have practical knowledge.

Learn the terminology of 3d printing and find out how to apply it to your printing.

Keep up to date with changes in the slicers and know what are gimmicks and what will improve the quality of your prints.

And there is even a short course on using meshmixer to manifold your models and manipulate them.

Seeing dink with a dragons arm is an interesting concept, but shows what can be accomplished.

But i would say it really doesn’t matter at what level you are at – there will be something to improve your print quality or print process.

As there is no contract and you can sign up and leave when you need to it is worth keeping their site in a bookmark – just in case you come up against a problem you think ‘i need to have a rational conversation with an expert to solve this’, rather than all the noise you get on social media.

And you get to go through the latest training…

So seriously , check it out – see if the two week trial offer is still there, if not signup for a month and see what you think.

I will be dipping back in in a bit…

Maybe see you in there….

Anet A8 and TPU : First Steps in Getting More Flexible

Think it is difficult printing with the Anet A8 and TPU? Read this article to the end to find out my hints and tips

Even a cheap 3d printer can print TPU if setup right- try this one (#ad)

Ok so you have bought an Anet A8 3d printer.

You have downloaded some models from Thingiverse or other sites.

These have been hit or miss, but more hit than miss.

Only using PLA.

But you know your printer is capable of much more than this.

It can cope with PETG, ABS, nylon and flexible.

You have done your research.

ABS – too toxic without an extractor to remove the fumes ( or from my point of view – memories of trying to repair motorcycle plastics)

PETG – need an enclosure to prevent draughts and get stable (ish) temperatures over the bed to prevent warping.

Nylon – soaks up the water and needs special drying.

This leaves flexible (TPU or TPE).

So what is it exactly

Flexible polymers are lumped under the heading TPE (ThermoPlastic Elastomers), with (#ad) TPU (Thermoplastic PolyUrethane) being the most commonly available.

ninjaflex tpu filament
Check Out Ninjaflex Filament Here (#ad)

Most are known by their brands name – like Ninjaflex or Flexismart.

They are comprised of a rubber compound along with a hard plastic, the mix of the two giving the degree of flexibility.

You see the images of people bending this, but until you have tried it you won’t believe how flexible it can be, or how useful that can be – for phone cases and the like.

What do you need to know about printing TPU

You know how to set your printer for PLA…

So now you need to know how to set your Anet A8 3d printer up for TPU.

There are two main things to remember when printing with flexible filaments.

You can’t push too hard, as it is flexible and will bend.

And take your time, slow your printer down.

With PLA you managed to get close to 100mm/s printing speed, well if you try that with TPU you are likely to fail.

You can’t melt it fast enough or push hard enough to get the filament out of the hotend.

Typical printing speeds are in the order of 30mm/s max, ideally 20-25mm/s, so things are going to take a bit longer to print.

You ideally need to switch off retraction as well.

Pushing and pulling back on the molten filament may cause a jam, the last thing you want.

Careful setting of the temperature will reduce to a minimum the amount of stringing you get.

So set the nozzle temp to about 225C and if you suffer too much stringing then reduce your nozzle temp by 5C and try again.

You will know when the temperature is too low by the poor adhesion between layers or the part not sticking to the bed.

The bed needs to be about 50C, I also used blue painters tape.

You are not supposed to heat the bed with blue painters tape, but I found it worked better with heat and tape.

You can print onto glass and get a very smooth finish to the bottom of your prints.

I will be trying onto polyamide tape in the future and will keep you updated on the progress.

That all important first layer

With PLA – you know that unless your nozzle is just right you will be starting again…and again…and again.

With TPU as it is rubbery there is a little more flexibility in the gap between the nozzle and the bed.

This doesn’t mean that you can be sloppy when leveling you bed, but it does mean that there is more leeway.

If the gap is too small and the pressure builds up in the nozzle and backs up the molten filament, you may get a blockage, so err the gap on the larger side.

As long as you get a bit of pressure onto the bed it will stick.

Especially if you are using heat and blue painters tape.

Make sure there are no overlaps on the tape, butt the edges together.

I tend to lay the edge down and wipe away to lay this down.

Replace any strips that get damaged when removing parts.

If it is not sticking then increase your nozzle temperature by 5C and see if that helps.

But check the nozzle clearance.

Replace the tape after 5 or 6 prints in the same area.

First prints

So what did I print as a first TPU print?

faceted ring thingiverse

A faceted ring, why – this was the only model which said it finished in under 5 mins.

Did it go well?

The first time the filament had not fed into the hotend quickly enough, so I had half a layer that didn’t print. so I stopped the print.

The second attempt showed up the flexibility of the filament as it decided not to go down the throat and wrap around the extruder gear.

But with this filament, unlike PLA, you can just reuse that bit.

So I printed off a flexible filament guide to reduce the gap between

tpu faceted ringthe extruder gear and the throat.

That appeared to cure that and the ring printed perfectly.

So another challenge I have had is printing a windsor chair – I failed a few times with PLA as the bed wasn’t set correctly so…

With it sliced again for TPU, the four leg patches stuck perfectly, so hopeful…

Then printing higher I could see what they said about stringing.

Between the legs was this fine webbing, ok so I will get rid of that when it finishes.

Watching it do the bridges between the legs, I wasn’t so sure about the bridging ability of the material.

The seat turned out ok and the back with it’s open frame was covered in stringing.

Overall it printed ok.

Not the prettiest print but it stayed on the bed and finished.

Cleaning up TPU

New scalpel blade.


tpu chair cleaned up with scalpel

Damn this stuff is flexible.

Rubbery and hard to cut.

So yes with complex models I will need to play around with the temperature to reduce the stringing, I think mine is too hot at the moment.

Am I impressed that you can print a flexible filament – hell yes.

I still smile picking up the chair and flexing the back of it.

The ring looks more like an o-ring, so is less impressive, but the chair…

Am I going to continue with this stuff, hell yes.

I designed some covers for a motorbike, they cover up the swinging

bike bolt cover arm bolt.

Previously I had printed them in PLA, they fitted quite tightly, but at the speeds this bike goes are on the roadside somewhere.

With this flexible filament then they will have a lot more grip, so are on the printer as I am typing this up.

I can here it singing…Oh hang on…. it’s stopped so may have finished.

I have now found I have a lot to learn about flexible filament design.

The flanges are too thin and too flexible to hold them in.

Using the outer face onto the bed of the tape causes them to be too

bike covers matt finishmatt.

I will try to post process them, but probably will struggle to find a material flexible enough bend with the filament.

Will I give up …no way.

What other ideas do I have?

Well what about replacement heels for shoes?

It does bring up a few questions…

  • Is it strong enough
  • Will it withstand walking on
  • How long will it last
  • Is it grippy enough to be safe?

All of these questions will be answered soon as I have a pair of my other half’s to reheel.

Am I impressed.. Oh yes.

So thanks to 3d warhorse on Amazon.

I bought the 0.5kg reel to try.

Apparently it can be used in a 3d pen as well.

I wonder how well it will stick to PLA to create hinges.

All I have to do is to keep it dry.

So back into the bag with some more silica gel.

Would I Try It Again?

If you have only tried PLA till now, then I reckon your next step is to buy some of this and give it a go.

Just remember to slow your printer down, raise the temp of the nozzle, switch off retraction (or at least keep it a very low value) and use blue painters tape on the bed…and you should have some good initial results.

From there you can tweak your settings to make it even better.

crushing chair

If you have any more tips on printing TPU then please leave them in the comments below

If your printer has a bowden extruder, can you print with flex filament.

The theory is yes as it is the bit between the extruder and the throat that is important.

But you have to bear in mind that along the full length of the bowden tube the filament will be compressed so there will be a lag when the extruder starts to push and the filament comes out of the hotend.

So add a couple of skirts around the outside.

I do have a printer with a bowden extruder so can try this out.

And you won’t be able to use retraction with any accuracy on this machine – but may be able to take the pressure off to reduce stringing.

But I don’t see it as a restriction.

kitchen blow torch
just be careful how long you keep it on the model (#ad)

I have heard that if you use a (#ad) kitchen blow torch (you know…the

ones to caramelize the top of things) and wave it over your model, not stopping in one place, that you can melt the stringing and make it disappear.

Oh another tip – from what I hear TPU can jam easily.

So I have got into the habit of leaving my Anet A8 printer nozzle to cool down to ambient before switching it off. This will prevent heat creep into the throat making it more difficult to push the filament through next time.

And don’t forget to take your model off the bed while the bed is still hot – taking it off cold may prove tricky!

Please leave a comment below if you have used a bowden extruder with flexible filament- either successfully or unsuccessfully. or you have used your anet a8 3d printer with TPU.

Thanks for reading