All posts by phil stanton

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

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 TPU (Thermoplastic PolyUrethane) being the most commonly available.

ninjaflex tpu filament
Check Out Ninjaflex Filament Here

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 ring

the 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.

and….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 swingingbike 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 finish

matt.

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

I have heard that if you use a 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

Phil

 

Anet A8 hotend problems : leaking filament

This article is how to find out whether your Anet A8 hotend has been assembled correctly.

 Common Problems with the Anet A8 hotend

There are three main problems associated with the hotend which anet a8 hotend :leaky nozzlewill be dealt with in this article.

  • Filament leaking from the top of the heat block
  • Filament leaking from the bottom of the heat block
  • Hotend loose when heated.

When you receive your Anet A8 the hotend will probably be assembled, mine was. What you don’t realise is that it is probably assembled wrong – as mine was!

You assemble the unit onto the printer and start printing.

After a short while there appears at the top of the heatblock some molten filament.

If you are unlucky this can increase and drop down onto your printed model and either catch with the nozzle or cause detaching problems when the nozzle knocks your print off.

In the best case where it doesn’t drip you are left with a lot of filament stuck to the top of the heat block, requiring cleaning up.

Or the filament starts oozing from the top of the nozzle and drips onto your model causing problems.

Or after heating up the printer you start printing and notice that the heatblock is spinning around and causing printing problems with your model.

Whichever it is this needs to be rectified.

 What is the hotend made up of?

The Hotend is contructed of a few parts. these include:hotend components

  • The throat
  • The liner
  • The heat block
  • The cartridge heater
  • The thermistor
  • The nozzle

The liner is usually made out of PTFE material, slippery and heat proof. This is the insulation while the filament goes through the extruder.

The PTFE tube is fitted inside the throat, made of stainless steel. It goes right down to the bottom to be butted up against the nozzle. The throat forms the connection between the extruder and the hotend. It also forms the heatbreak to prevent heat from the hotend from backing up the throat causing blockages.

The metal heater block holds all of the parts of the hot end block together.

The Cartridge heater, a 12v 40w heater raises the temperature of the heat block above the melting point of the filament.

The thermistor gives the controller some feedback on the temperature of the heat block. Once close to temperature the heating is cut back so that it doesn’t overshoot. It closes the loop of the cartridge heater into the heatblock to the thermistor, back to the controller.

The nozzle is the melt zone. Once liquid the filament is forced through the opening in the tip of the nozzle. The semi melted filament forms a plug which pushes the molten filament out of the nozzle.

How to disassemble your hotend properly

Once you have used your hotend it will be fill of filament.extruder assembly removed from printer

If you try to disassemble this when it is cold then you stand a good chance of breaking it.

If the nozzle has stuck this can shear off when trying to unscrew it.

Or the throat may snap, again with the filament stuck to it.

So what do you do?

I tend to cut off the filament at the top of the extruder rather than trying to remove it by pulling out.

Switch your printer on and warm it up, it doesn’t have to be at the melting temperature, just above the transition temperature from rigid to flexible – which on PLA occurs at about 50C.

So set the printer to preheat PLA – if PLA is what you are using, and go back to the main screen. Watch the temperature until it rises above 60C and you can then switch the printer off.

To remove the nozzle at this time, use a pair of molegrips ( visegrips) to hold the heatblock- carefully avoiding the heater cartridge and themistor.

With the correct size spanner unscrew the nozzle. This should turn relatively easily now the plastic is warmed.

Place it down on something that can withstand the heat without melting or being damaged. – I put it on the printers bed.

On the Anet A8 the hotend is held in place with the lower bracket of the extruder motor.

If you undo the nut and the allen bolt holding this bracket to thehotend removed frame and the two screw holding the extruder motor you can remove the throat/heatblock/retainer completely.

Now while it is still warm the nut can be tightened up to the mounting block and the heatblock gripped in the molegrips again.

The throat can be removed from the heatblock at this time.

If it proves difficult then remove the mounting block and add throat removedanother nut to the throat.

Tighten the two nuts together, and using a spanner on the nut closest to the heatblock, use the molegrips to remove the heatblock from the throat.

You may need to clean out the threads of the heatblock or replace it if there is damage to the threads.

Check the throat for damage to the threads or to the PTFE liner. If it is blackened it may have been overheated or bits of filament may have overheated – these can break off and cause partial blockages in the nozzle while printing.

As they are only a couple of dollars then replacement would be the

removed nozzle
all the black is overheated filament ready to block the nozzle

best move – keep these in stock as consumables.

Remove any remaining filament and make sure that all of it is cleaned before reassembling.

 Assembling Your 3D Printers Hotend Correctly

To assemble your hotend correctly make sure you have all the pieces available.

Nozzle, throat, heatblock and that’s it. If the heatblock has the hotend partscartridge heater and the thermistor installed make sure you are careful with the wires. You don’t want to reassemble the hotend onto your printer just to have the wires break.

Personally I reassemble the hotend cold and have had no problems, others are not so lucky and perform the last stage hot. This is something you will need to try and see which way works best for you.

Taking the nozzle, screw this into the heatblock by hand until it goes

tight.

Then unscrew it by 1/2 a turn.

Now take the throat and screw that in until it is stoped by the nozzle.

Using the molegrips, hold the heatblock to stop it rotating while using a spanner to tighten the nozzle onto the throat.

Don’t over tighten the nozzle, it need about 1/16th of a turn to take up any slack in the threads and to prevent it leaking from the joint between the nozzle and throat.

After you have tightened this examine the nozzle to see that there is still a small gap between the body of the nozzle and the heat block.

Now the nut to hold the hotend to the extruder can be screwed down the throat, if it was removed.

And the mounting block screwed onto the throat.

The throat end should come to the top of the mounting block or slightly protrude. The wires for the heater and thermistor will orientate themselves to the correct position as they were when you took the assembly off.

Offer the assembly up to the extruder and screw in the allen bolt – do not tighten. Align the mounting block and tighten the nut up to the extruder mount. Tighten the allen bolt.

Place the spring for the extruder in the correct position and holding hotend installeddown te extruder motor screw this back in with the two allen bolts. It is easier to locate the one furthest away from te spring first and using that as a pivot locate the one closest to the spring – then tighten both up.

You now have a reassembled hotend which should not leak.

Note: if your hotend becomes loose when you have heated it then hold the heatblock in molegrips and tighten the nozzle  – make sure it is not tight against the heatblock when fully tightened.

Testing your hotend

Switch on your printer and make sure that it starts up ok.

Locate the hotend temperature menu and start the process.

Go back to the main screen and watch the temperature rise on the hotend.

Make sure it stabilises where you set it.

Straighten the end of your filament and feed it into the extruder. Pressing down on the tension spring will allow you to feed the filament in without turning the motor.

Manually push it through until you see filament coming out of the nozzle.

Stop pushing. and release the tension spring.

Look for signs of leaking, both at the top and bottom of the heatblock.

If there are then hold the heatblock with the molegrips and tighten the nozzle.

You now have a working hotend on your 3d printer which will not leak.

After clearing and reassembling your hotend you will need to go through leveling your bed as the height of the nozzle will not be the same as before.

Other solutions for the Anet A8 hotend

I have heard that people are putting teflon tape around the threads to prevent leakage- if you get the joint tight between the nozzle and the throat then you really don’t need anything else.

And don’t use thread lock on the threads of the throat as you may not be able to disassemble it in the future. If there is still a problem then the joint between the nozzle and the throat is not correct and needs attention.

If you really cannot get it to stop leaking then try to flatten the faces nozzle flattenedof the nozzle and the throat on some wet n dry paper – if you don’t get it really flat it may cause more problems than solving.

The complete new assembly is available relatively cheaply to purchase from Amazon. Don’t forget to check it before fitting as most manufacturers don’t assembly these properly from the factory. Go through the assembly process of loosening the nozzle and tightening the throat down onto the nozzle.

If you find that the teflon tube is blackened at the end where it meets the nozzle, it will be worth checking your temperature settings for the material you are using. too hot and it will start to overheat and stick internally leading to more blockages.

I tend to polish the inside of my nozzle before the first fitting – does this do anything? well I have very few problems with partial blockages so every little helps, and it only takes a few minutes.

Thanks for reading and please fill in the survey whether you tightened your anet a8 hotend hot or cold.

Do you assemble you hotend hot or cold?

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Phil

Anet A8 Bed Leveling : How do You do Yours?

Having had my anet a8 for over a year now I am getting quite used to it.anet a8 bed leveling : smashing printer

I am just going through a mod for adding an e3d v6 all metal hotend clone, with interesting results, but that’s another story.

One of the main things I with my anet a8 at the start was bed leveling.

I would go through the Anet A8 bed leveling process and the prints would not stick (nozzle too high) or the filament would not come out (nozzle too low).

What was I doing wrong? Why wouldn’t it work properly?

But I understood that bed leveling was nothing to do with using a spirit gauge to get the bed perfectly level. It was to do with getting the nozzle the same distance above the whole of the bed. So you are adjusting your bed to the height of the nozzle with the Z axis set to 0.

Make sure your Z axis height is the same on both sides first.

Before You Start the Anet A8 Bed Leveling Process

Well there were a few things I had to do first to stabilise my machine before the leveling worked.

One of the main ones was to add a base and screw it down.anet a8 screwed down

If you move the front up by 0.4mm then the bed leveling will be out- and this may happen with the weight of the bed moving back and forth if you don’t bolt it down.

Create a Solid Base for the Anet A8

So screw it down to a flat piece of wood or a cabinet top.

I created a box for mine so I had storage underneath it.

The top was is made of laminate floorboards.

The sides of the box are made out of tongue and groove floorboard with the groove modified to accept the top ( the inner part of the groove is gone and the top rests on the ledge left).

A brace has been put across the top at the front to stiffen up the structure. As can be seen in the picture above.

Sort out the Z Axis Stop

z stop mod
Anet A8 Z endspot holder for 2017 version by daveposh

The other one which makes all the difference to stock parts is to change the z stop. Mine would always start to work loose, so the z zero height would be adjusting, messing up the bed leveling.

So I used this anet a8 z stop.

Make sure the screw goes into the plunger straight – mine is crooked, as this can give you unexpected results when adjusting the z height.

With this mod one turn of the screw will adjust the Z axis about 2mm. So you need to be light with the adjustment.

If this is the adjustment before your first print then tighten up the z stop as much as possible and use the bed adjustment to bring the nozzle close. Once printing, make it a priority to print off the z stop adjuster.

Check your Bed Flatness

Another thing to do is to check your bed for flatness with a steel ruler – you may find that at the very edges it does bow up or down as well as a little bit close to the hole where the thermister is.

You can either accept this as I have or flatten it on a piece of float glass with a sheet of wet n dry taped to it – don’t forget to add water with a little dishsoap as a lubricant.

I have not tried this but it should give you a flat surface to work with if the bow it too much.

Clean Your Nozzle

Before leveling the bed check that the nozzle is clean of any filament clean the filament offsticking out. This will cause an error to the height adjustment and will cause failed adhesion prints- from experience!!

If there is filament sticking out then switch on the printer and go to control → temperature and set the nozzle to 190. Press back until you get to the home screen and wait for the temperature to stabilise.

Wipe the nozzle with a clean paper towel or cloth, making sure you don’t burn your fingers.

Set the temperature to 0 and allow to cool, make sure there is no ooze as it was cooling down!

Tip for the Threaded Bottom Plates

If you have one of the older Anet A8’s then you may have the screws going through the bed and threaded into the lower plate. If this is the case and they are stiff to turn then carefully remove them and add a bit of grease ( I use lithium grease) to the threads and put them back in. This will prevent the threads from binding and stripping. Makes it a lot easier to adjust as well. I used a spray can as my screws were starting to bind and this could spray between the spring. It worked and they are loose.

If you have one of the newer ones with a clearance hole and wing nuts underneath the lower plate then it might be worth considering printing off the easy to use round adjusters. The only thing I would add is some kapton tape over the lower part of the bed where the washers go to add another layer of insulation, I have heard of the bed shorting out with the washers.

Anet A8 Bed Leveling Process

Switch on the printer, leave it cold.

Make sure there is no filament sticking out of the nozzle.

Send the printer to its home position.

Manually raise the z by 2-3 mm.

Move the X axis by 25mm.

Move the Y axis by 25mm.

Move the Z axis slowly down to the bed and place a piece of paper between the bed and the nozzle. Or a feeler gauge of 0.2mm.

There should be drag on the paper or feeler gauge.

Looking down from the top

Turning the screw adjuster anticlockwise will raise the bed and turning clockwise will lower the bed.

With the nut adjuster turning anticlockwise will raise the bed and clockwise will lower the bed.

If there is a large gap then you will have to go around two or three times before it settles.

Don’t press down too hard as this will possibly put pressure on the lower plate and throw out the adjustment.

Once you have adjusted this corner then raise the Z axis by 1mm and move the x axis to 175mm ( you don’t need to be exact).

Lower the Z axis to 0mm.

Now adjust the front right adjuster to feel the drag on the paper.

Raise the Z axis by 1mm.

Move the Y axis to 175mm.

Lower the Z axis to 0mm

Adjust the rear right adjuster for drag on the paper.

Raise the z axis by 1mm

Move the X axis to 25mm.

Lower the z axis to 0mm.

Adjust the rear left adjuster for drag on the paper.

Raise the Z axis by 1mm.

Now adjust the Y axis to 25mm.

Go to the home position then raise the Z axis by 1mm and go back to X 25mm, Y 25mm.

Lower the Z axis to 0mm.

Check and readjust if necessary for drag on the paper.

If the drag is still the same as it was then good. If not, it is a pain, but go around again and readjust all four corners until you are confident that the gap is consistant.

After the Manual Process

Test print

I use a single layer circle test print 100mm diameter 0.2mm thick.

Download the test circle.

If you now load up the test print, wait for it to start printing.

You will see what is happening with the nozzle as it comes down to make the first part of the print.

If it doesn’t stick then adjust the corner to either raise the bed if the nozzle too closenozzle is too high or lower the bed if the nozzle appears to be too low.

If the print hasn’t stuck after the first half circle then abort the print.

Remembering that a turn of the screw is 2mm tweak the adjusters in the direction you need to and start the print again – after wiping the printers nose.

Once this test print sticks and prints completely then use a marker pen and mark the forward direction so you can orientate the print. Peel it off carefully and measure the thickness of it. Measure in the two axis – both diresctions – is it consistant at 0.2mm (ish).

Use this test print to more accurately setup your printer – don’t be too obsessive.

Print it again and check for consistancy.

Once you are at this stage then you know that any print you do now should stick with a first layer squished down.

Remember to go slightly more squished rather than less as once your model goes upwards it has less chance of detaching if it is adhered to the bed more.

Every few prints ( preferably before every print) clean your print bed.

Did you manage to get Your Anet a8 bed leveled?

Good luck with this, and leave some comments if you feel that you have a better method for anet a8 bed leveling.

Thanks for reading

Phil

3d Printing Modeling Software : What are your choices for free?

Which Free 3d Printing Modeling Software is Right for You?

Once you have owned a 3d printer for a few months and got to know3d printing modeling software aston it. Downloading the latest part off Thingiverse or youmagine  gets limiting, you want to explore what you can do with your printer.
So you start think ‘what 3d printing modeling software is out there for free?’

Well this article shows you some of the packages which are avaliable for free.

Take the poll at the bottom to show the popularity of your cad system.

There are paid ones, like solidworks or rhino which cost thousands, There was one which only cost tens of dollars, cubify invent– I found this one just as I was starting to get into designing – and didn’t buy it – a week later I couldn’t buy it, the manufacturer had discontinued the low end version and continued with the high end costly version.

What I have found with cad is that if you ‘click’ with how it works, you like it – if you struggle with the core concept then you will struggle to create models with it.
So work on understanding how the cad system works in the first place – check whether there are any training modules or a community and take it from there.

So which ones will we take a quick look at?

From my engineering background, designspark mechanical is the first one I would go for, autodesk fusion 360 ( or 123d as it used to be known), openscad, sketchup, autodesk tinkercad and blender.

There are plenty more but these are the main ones used currently – I am sure that others will come and take their place.

So let’s have a look at the cad systems

Designspark Mechanical

Designspark mechanical was developed as an addon to the already going designspark pcb, the mechanical addition gave the designer the capability to add their circuit board to a mechanical package.designspark mechanical opening screen

The mechanical cad system is a simple and uncluttered interface.
There is more than enough capability for the majority of cad designs most of us will do and the fact that it is a simple export to get the stl file out of the cad is an added benefit.

Installing the software is simple, but only 32bit and 64 bit versions for windows are available.
You will ned to be connected online every 30 days for the software to check your license. But between times you can happily use it offline.
There are a few ads present when you start the software, but it is free. This screen is easily closed by clicking on the ‘x’ at the bottom of the panel.

Starting a new design from file –> new design – and you are presented with an orthographic screen.
If you are online then the quick guide on the right is active, worth a browse at the start to get the hang of it.

The orient button along the top menu ( a box symbol – click the drop arrow) allows you to choose which view you want.
If you select top view you get the x and y standard drawing screen.
For me the scroll is backwards from intuitive, scrolling forwards makes it smaller and backwards makes it bigger. For most of the other cad I have used it is the other way round.

The standard sketch tools are next to the orient block, these include all of the 2d drawing tools, line, rectangle, circle.
To make your item 3d then you have to use the pull command -this pulls the object in the direction the mouse pulls it.
The combinational tools are located to the right of this group allowing you to merge or intersect the objects.

You are able to utilise the vast library which is the mechanical parts within RS componients – if you know you want a box, then simply pick a box of almost the right size and alter it to fit. Pick a connector and place it into the box where you want it and combine it to form the cutout of the right size. So there are no excuses for getting the size of connectors wrong.

There is a fair amount of help from the distributor, creators and user community.

This cad is more for the mechanical rather than sculpting. It is a little limited and clunky feeling but with it’s easy to use clean interface you should have no trouble picking it up.

Autodesk Fusion 360

Autodesk fusion 360 is a  full 3d cad system, at the time of writing, is freely available for schools, hobbyists and small businesses.
There is more than enough capability within this cad system to fusion360 playingcreate whatever you want.

The user interface is clean, with most of its capability tucked away behind a top level menu.
Each top level menu has many functions behind it. Opening the create menu will allow access to a multitude of shapes, including cylinder, box, thread and sweep.

I had difficulty with the display at the start and had to change to the older direct x 9 driver – requiring a restart. i blame my old computer.

You will have to sign in, but you do not have to be online all of the time. Every two to three weeks it will need to validate the license.

Changing the view is easy and clicking on any of the surfaces of the box shown in the upper right hand corner will take you to that view. You can also rotate and pan the view by using the controls at the bottom center of the screen.

Multipart designs can be easliy assembled, with parts being able to be turned on and off.

If you want to work on a design with others then the 9 square menu icon in the top left corner will allow you to merge with others to see the latest design. This is a feature not seen on most low cost or free cad systems.

You can save your project as an stl file for the 3d printer or you can post process the design by sending it to one of autodesks other pieces of software meshmixer.

There is plenty of online help files and videos to show you how to create almost anything.

Openscad

Openscad is a bit of a depature from the usual cad system. This user interface is based on describing the model.
You specify your model in terms of text – so ‘cube ( size = 10,10,10); ‘ openscad letter boxwill draw a cube 10 x 10 x 10 on the origin.
You preview what you have described by clicking a button and if you are more used to programming that visually dragging and dropping this may be a choice for you.

Is it easy to learn? You really need to read some of the help file before you start to know what commands do what.
There are a small range of native shapes you can employ so a bit of practice and you should become conversant with those.

If you want to move it anywhere other than the origin you can use the translate function, or rotate function in front of the definition of the cube.
So translate ([10,10,10]) cube(size = [10,10,10]); puts a cube away from the origin.

It may seem very much like programming but is quite easy to learn.
You can build up a library of parts and combine them with boolean expressions.

The scripts can get very large, but you can always subdivide things down.
It is very easy to go into the script and alter values to change the size or placement of items.

But if you struggle with being able to visualise items in their basic shapes this may not be the cad system for you.

Sketchup

Sketchup, now owned by Trimble was owned by Google.
It is in two versions, a free one sketchup make and a pro version, which costs $695 (in 2018). At the time of writing I can see that sketchup free will be going cloud based, there is sketchup for web – where you work in a browser rather than offline and have to login to sketchup make with 3d printeruse the software.

The free version is lmiited in functionality, but is adequate for a lot of modelling, so if you get on with it then use it.
On the site where you download it , there are a lot of tutorials to get you started.
Once downloaded and installed, starting sketchup you will be asked to add licence. If you ignore this and click on the template tab and scroll down to the bottom there are two templates for 3d printing, you can choose between inches and millimeters. Or you can just use the standard template, the advantage with using the 3d printer template is that you can see whether the model will fit within your printer, but if you are making a multi part model this will be overruled. You can always delete the printer box from the design space.

With sketchup you cannot import a stl to edit it and saving for the 3d printer will be exporting an obj file, without an addon.

Down the right hand side on the screen is an instructor, showing you how to use the tool selected.
As with most cad programs, some procedures are easy and others hard, if you don’t know how to model them.
Very soon after starting skethup you will find the mini toolbar a pain, to get an expanded toobar go to view -> toolbars… and untick the basic and tick the large tool set.

Why is there a free version and a pro version, well after 30 days your functionality will be limited and they want you to upgrade. It maybe worth investigating the online version.

Exporting to stl is possible with an extension. To add an extension goto window → extension manager.
Once the window comes up then at the top type stl.
Select sketchup stl and install it.
This will add the functionality to import and export stl files.
Importing the stl , it will come in as a group and need to be exploded to modify.

So if you want to create simple model easily then sketchup may be worth trying.
Watch how easy- once you are used to it you can make a table

Autodesk Tinkercad

An awful lot of people are using tinkercad online cad program.
Once you get started withit you will see why.

Sign up and get through the new gdpr screens (what a pain) and you are offered training to get used to the system.
It is worth going through this to see how the system works.

Once you have had enough of that then going back to the home screen and clicking on start new design will take you to the design area.
It has a slightly weird view – when clicking on the front face of the view cube – you are left looking slightly up rather than directly onto – clicking the orthographic view ( button down at the bottom on the left ) takes you to the standard front view.
The basic shapes are as easy as building blocks to add and manipulate.

Don’t forget to look closely at cylinders for the number of sides or your print will not end up smooth. I would increase the number of surfaces after you have finished the model as a large number of surfaces will slow down your model.

Once you get used to the interface then I can see that it is a very easy to use 3d cad system.

If you haven’t already got a 3d printer but want to design and print it, then this cad system allows you to send your design to a number of maker places where you can have it made.
You can download the stl for your printer or post your latest creation on social media.

Would I use this – for a quick way to get a basic model and, I am sure if I stuck with it, I would find it is capable of a lot more than I think, but I prefer an offline cad system.

Blender

hmm… I wonder which side you will come down on with Blender? Maybe you have already tried it and are ready to pass this section by or you are waiting for my thoughts.
When you start blender you are shown a screen with a cube on it. A load of buttons a few tabs and …
Help… please…

The controls are not intuitive as has been in most of the above cad systems. The left mouse button in most cad systems will select things, not so in blender, this sets the 3d center position.

Moving objects selected usually is click and drag then drop when released. Do this in blender and you are still moving the object when you move the mouse – you need to right click to select and then left click to release.

And keyboard shortcuts or key shortcuts as they are known in the help file, there are hundreds – you won’t need to know most of them unless you are getting into making animations, but getting to some of the functions can be tricky using the menu structure.

With a relaxed mind and a willingness to learn you will be presented with a cad system which will far outperform any model you want to make. You will be constrained more by what your 3d printer can print.

Using the full capabilities of blender you will be not only creating a static model but animating it and creating a short movie, but maybe this is the way you will be advertising your hard work in the future.
Blender has a thriving online community, I know this is very important when learning something new like this, along with plenty of online tutorials, manuals and practical advice.

After installation, running Blender you will be presented with a cube on the screen, with 5 settable areas.
Clicking at the top left of each of the areas allows you to choose what information is shown in each area.
You probably won’t need the timeline or the plalyback ( the two at the bottom), so you can left click on the little hatched area just under the selection and drag it to the bottom of the screen.
If you want to put them back you can left click and drag it back.
Have a play at adding primitives to the screen and you will see the difference between this system and the other cad programs.

Move the primitives around – on axis by left clicking the axis you want to move on or right clicking and moving freely – don’t forget to left click to drop it after you place it in position.

One important addon for 3d printing is the 3d print toolbox.
You can add this via the file → user preferance menu
select addon tab.
Scroll the addons down and click on mesh- then tick the 3d print toolbox item.
This will allow the model to be checked for errors before passing the file onto your slicer.

You can save a stl file from this cad package.

After moving the areas around why not save it as your default config.
Press ‘a’ after clicking in the main screen to deselect everything then press ‘a’ again to now select everything.
Pressing delete will remove all of the objects from the drawing area after clicking on the confirmation box that appears.
Click view → left and you will have a screen that looks more like a standard cad package.
Click file → save startup file and this will then be what you see on starting blender.

Is it a powerful cad package – yes.
Is the user interface friendly – no.
Will I use it a lot – possibly, depending on how much time I can spend with it.

It looks like an extremely good package, with a lot of features that will make very good models. Even though I am more used to engineering cad it may have it’s place and time to allow for artistic license.

Which Operating systems will they run on?

I know there are loads of other packages around now – even for free – the likes of freecad, microsoft 3d builder, brl cad, sculptris – there would not be a person out there who would trawl through all of them – so I have chosen what I see as the top ones at the moment.

So a quick run down of what operating systems the packages will run on.

Operating System
Program Designspark Mechanical Fusion 360 Openscad Sketchup Tinkercad Blender
Windows
Mac X
Unix X X X

I hope you have enjoyed my brief look at the cad systems and will have a go at one or more of them. As I say choosing a cad system is personal and you need to really enjoy the way the package works or you will be struggling to create even the basic models.

Approach each cad system with a curious mind, asking how can I model this – watch a few training videos, which will teach you the basics and some techniques you may use in the future. But the main thing is to enjoy your time designing your model. The cad system should become a tool to be used to create your model.

Don’t forget to watch the training from the other cad programs – you may pick up a tip or two- I know I have!!

So let me know in the comments which 3d printing modeling software you have chosen or tried and whether you stuck with it.

Which Cad system are you using?

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Thanks for reading

Phil

Anet A8 fan- do you want to hear the silence?

One of the most frequently asked questions on the forums is how do Anet A8 fan upgrade I silence that Anet A8 fan noise?

Well this article will explore the options you have.

 

Which Anet A8 fan is installed?

You have two fans which can be installed when building.

Most people ditch the extruder cooling fan or modify it  and only replace it when they have issues with heat on the extruder motor melting the filament causing jams.

The other is a radiall fan which is used to cool the filament as it comes out.

The radiall fan is capable of moving 18 cfm (cubic feet per minute) at 7000 rpm (revs per minute).

Supplied with a voltage of 12v it draws 0.18A so consumes about 2watts of power.

The bearing type is a sleeve bearing.

So when you are printing you enable this fan to come on to cool your print.

It is not on constantly or fully on, this is the one you can control either from the gcode file or the menu screen.

It will not start below a certain percentage and ramps up to full speed.

After a few weeks of operation this fan may start to get noisier, and maybe even squeal a bit when starting up.

To start with lifting the label and placing a drop of oil on the spindle quietens it down, but very soon the noise is back.

What options do you have?

Essentially you have got three main options.

Replace like with like. So keep going with a sleeve bearing.

This is a plain bearing with a pin in a sleeve.

The lubrication is good at the start but quickly moves away from the area where it Is needed and wear starts, along with vibration and noise.

Increased temperature will increase the wear of the bearings.

As said above a drop of oil will increase the life of the bearing.

The fan starts out noisy and gets noisier throughout its lifetime.

These types of bearing will fail with no notice – so if you do go this way then keep a couple of spares in just in case.

They are the cheapest of the options.

Or look into a ball bearing fan- make sure you get the dual ball bearing as some of these are ball bearing on one side and sleeve bearing on the other.

The ball bearings or bb fans are more expensive but longer lasting.

They tend to be louder at the start than sleeved bearings, but will quieten down with run time.

The performance out of the box over time is good.

Again higher temperatures will prematurly wear the bearing due to loss of lubricant.

They have a more predictable failure mode by getting noisier before failing.

Or you can go with one of the newer hydrodynamic bearings.

Although these are essentailly a sleeved bearing they have been modified to allow the lubricant to circulate.

They are the most expensive, due mainly to licencing fees.

They are very clever in the fact that they use the fans own rotation to create a flow of fluid around the bearings.

These are extremely quiet bearings and fans – almost whisper quiet.

These bearings are sealed so should not lose lubrication over their lifetime. Even when runnig at elevated temperatures.

Failure of the seal is probably the major cause of fan failure

You do have to watch out for some inferior types which are not so good, but generally all of these types are extremely quiet.

Another modified veriation of this type of bearing is the sso bearing, where a magnet keeps the bearing centralised to further increase its lifetime and allow operation in any direction.

The sleeve bearing and bb fans are readily available in axial and radiall modes.

But the hydrodynamic fans tend to only come in axial fans.

The actual volume of air throughput is lower with the hydrodynamic fans, so you may need a larger one to compensate.

But to get the silence I would go for a 40mm cooling fan and a 50mm duct fan.

axial
Amazon anet a8 40mm fan
standard 40mm fan – click to see the reviews

2 off dual ball bearing fans
Dual ball bearing fan X2 – click to see the reviews

40mm Gelid fan anet a8 fan
40mm Gelid fan- click to see what people think

bearing oil bearing ball bearing hydrodynamic
voltage 12v 12v 12v
current 0.12A 0.132A 0.05A
air flow 6.7 cfm 8.69 cfm 4.8 cfm
speed 7000 rpm 7500 rpm 4500 rpm
noise 25 dBA 31.5 dBA 17.9 dBA
guarantee ? 12 months 6 years

So there you have the main types of fans with their bearings.

Instead of that jet engine taking off why not treat yourself to a quiet print experience and change to a silent fan.

You will be amazed at the difference in noise, I know I was.

50mm gelid fan
50mm Gelid fan – click to see reviews

Here’s a link to the 50mm

The only difficulty is mounting it, being an axial fan you need to funnel the output flow down onto the hot extruded filament.

But there are mounts for this available to print and fit, so there you have another noise removed.

Bearing replacement is covered in the article on changing your bearings to igus bearings.

All you have left is the motor noise and this is dealt with by the addition of the trinamic drivers the TMC range.

These will be covered in another article.

Hopefully now you will be replacing that jet engine of an anet a8 fan to being one where you an hear yourself think.

Thanks for reading

Phil

Anet A8 mods : Adding an auxilliary socket to the Anet A8

anet a8 mods: 3d pen into auxilliary connectorAnet A8 mods are an ongoing process, here is another one to add to your printer.

This time it is something you may have not seen before: Adding an auxilliary socket to the Anet A8

I bought my Anet A8 a couple of years ago and built it up.

Having played with it for a while I found that I needed some tools which could all be powered from 12v.

This got me to thinking, what if I added an auxilliary socket to the Anet A8 to power these tools.

Instead of hunting for mains power block I could just plug and play.

I then got to thinking what could I use it for.

I came up with a short list – which I am sure will grow.

So I have:

  • Heat iron, to help with prints that come loose at the edges
  • 3d printing pen, to add more adhesion if necessary and fill in parts that partially fail to keep on printing – to repair supports that fail.
  • I am looking into a hot air pencil, the best I have seen are run from mains and are 1kw heaters!
  • led lighting to enable lights in places you don’t normally see them.

I am looking to keep the current drain from this socket down to 5A – so we have 60w to play with.

It maybe that I can design a hot air pencil as we only need up to 100C for ABS and abut 60C for PLA. So using a hotend heater and a 12v controled fan with a pair of thermistors – one on the heater to prevent overheating and the other in the air stream to control the fan speed to prevent cooling of the block too much – or even just a thermistor on the heat block to keep it up to temperature.

12v lighting to see under or around things to help with maintenance.

I may even be able to design a mini grinder to clean up the bed and maintain a clean surface to assist adhesion.

Under printer storage to keep all of these tools handy and tidy will be a necessity.

Fitting the Anet A8 mod auxilliary connector

So to start.

We need a connector.

I have been looking for a connector to fit the circular hole in the middle frame. This hole is about 10mm diameter.

I failed and found the din range of connectors, used for soldering irons and other tools already.step drill and din connector

Mine doesn’t come with screw locking but is just a push fit.

It also has a connector shell size of 13mm, this didn’t fit into the hole.

I have a set of step drills – very handy for jobs like this where you need to increase the hole size.

I selected the one which would give the right size hole and marked it with tape to prevent overdrilling.

As the frame is made from acrylic, known to be fairly brittle, I put the drill bit into a battery drill to keep the speed down.

Taking it slowly and hardly pushing the drill into the hole, it cut drill usedsurprisingly well for a bit.

You can tell when you are overheating the acrylic, this is when you stop getting swarf coming out.

At this point stop the drill, clean it off, get all of the melted plastic off and promise yourself that you won’t spin the drill that fast.

I found that the correct drill size was going to become one size up before cutting right through, so you will need access to both sides of the frame.

As it was I had to remove the screws from the power supply before I started, as the drill was going to be drilling into this.

Once the center hole is big enough for the connector to fit, I held it in position to drill one of the securing holes.

A 3mm drill bit went through the hole – so was used to start the hole.

Removing the connector, I upped the drill bit to 3.5mm, allowing for tolerance on a m3 screw and slop for hand drilling.

Don’t do what I did on the first hole, which is to drill all the way through with the 3mm bit and then try the 3.5mm – I could feel it trying to catch and chip, almost breaking the acrylic frame piece.

Fit the connector back and push a screw through the first hole to locate where the second hole should be drilled, and using the same technique of starting with a 3mm nd moving up to a 3.5mm , drill the second hole.

With hind sight – you maybe able to fit the connector behind the acrylic frame, only drilling two mounting holes to secure it. This will need to be tested for connector security as you may not be able to push the tool connector home fully.

Wiring up the connector

I chose a 5 way din connector.

This gives us options for interconnects.

We can add intelligence behind the frame or we can design tools with intelligence.

With a 5 way connector you also get the outer shell of the connector, so you do have 6 ways to connect.

The first connection was the 12v.

We need two wires and I chose the outer two pins as the 12v feed and 12v return.

This will be connected straight to the power supply and will always be on.

A future mod may be a switch to isolate this connector.

A thought for the other wires is to use a pair as temperature feedback, with the last pin as a digital input.

So all of the pins were wired up prior to final fitting.

A heavy ish pair of wires for the 12v fee and return, terminated the other end in fork crimps to be fitted to the power supply.

Lighter wires have been used for the other four wires , including the shell of the connector.

These have been tucked away behind the frame and taped so that they will not interfere with the power supply.

Fit the wires to the power supply terminals before refitting the power supply to the frame.

Then fit the auxilliary socket, bending the wires and making sure nothing is going to short out- it is probably preferable to cover the soldered connections with heatshrink to prevent shorting, but make sure they are not too long so as to interfere with the fitting of the power supply.

As I said before, tape up the unused wires and tuck them out of the way.

Make sure you create a diagram of the wiring, in 6 months when you design a superb new bit of kit, which blows up if connected the wrong way round, you will be fiddling about checking which pins the voltage is on.

When creating a diagram, make sure to show whether it is from the front or rear of the connector.

At present, all I have to connect to the aux socket is a 3d pen and this works well.

I am trying a 12v soldering iron to see if I can connect it to the socket, but have not tried this yet.

A 12v light can be made easily from an empty pen – or even printed, with a clip to secure it onto the frame and position it where you want light for maintenance or other tasks.

I am limiting the power drawn to 60w as I am still using the original power supply – with a 350w as a backup still in its box!

So there you go, now you have an auxilliary socket on your Anet A8, what are you going to plug into yours?

If you have a tool that you know will be useful to plug into your new anet a8 mods: aux conn fitted auxilliary socket for the AnetA8 why not leave a comment in the box below to share with us all.

So here’s a picture of the Anet A8 mods, the auxilliary connector fitted.

Thanks for reading

Phil

Ramps 1.4 connections : making them safe for the Anet A8

Make your Ramps 1 4 connections safe for upgrading your Anet A8 3d printer.

Ramps 1 4 connections upgradeRamps 1 4 connections : board

The ramps 1.4 board combined with the mega2560 is a common upgrade when the main board blows up on your Anet a8 3d printer.

It is not that you cannot get the original boards , but that the ramps, when programmed with marlin, gives you a lot more opportunity to upgrade your printer.

This is not without problems, one of the main ones I keep seeing on forums is the overheating of the connectors.

For the Anet A8, with it’s high current demand, the standard connectors are not good enough for the long term.

Yes they might work in the short term, but they will overheat and possibly catch the insulation on fire.

Can you safely use the ramps 1.4 on an anet a8?

You can replace the input connector, along with the bed, nozzle and fan connectors with ones suitable for the job.

I have looked into this and found a connector suitable for 20A camdenboss connectorscontinuous use.

It is a screw connector again, so you will need to check the tightness on a regular basis, but with this simple maintenance it will serve you well.

It takes away the pluggable input, but for the safety you get with this connector then to me that if justified.

It is a pcb screw terminal connector from camdenboss cbt0158/2

(ebay link)- it is a 2 pole stackable connector able to handle 20A continuous.

So this means you can make any length of connector you want as long as it is in multiples of 2 – so 2,4,6,8 etc.

We are looking for a 4 way and a 6 way, so it is ideal for this.

How do you replace the connectors?

You will need to de-solder the input connector and the output connector along the one side of the board.

I started with the input four pin connector.

You will need a soldering iron, solder, pliers, solder wick or solder sucker and flux cleaner.

 

 

Start by clearing your workspace, and if you have a helping hands then secure the board in this upside down, with the connector pointing towards you.

Dependant on how the board has been designed, with or without a lot of clearance for the pins, for me determines how the connector is removed.board towards you

If there is a lot of clearance on the connector pins with the plated through hole then you can heat each pin up and clear the solder from around the pin with the solder sucker. If it is tight then I tend to add solder to each of the pins and heat along the row so that the whole connector can be slid out with the molten solder allowing the pins to slide out, then you clear up the solder.

Normally I tend to use the latter technique on pins that are closer together, but I tried to clear one pin to see that it was quite a tight fit, so went ahead with the flood removal technique.

I will probably get shouted down for this technique, but I have used it in my last job with no problems.

What I do is to heat each pin of the connector and feed more solder onto them.

You then go along the row heating each pin up until the solder melts again.

You will need to keep doing this until you see all of the solder around the pins becomes molten at the same time- I will lay the soldering iron down to touch as many pins as possible at one time to help this technique, feeding solder on as necessary to keep good thermal contact without oxidisation.

You can hold the connector in your hand and put downwards pressure on it to see when it comes loose, don’t pull too hard as this can damage the plated through holes – even rip them out.

You might find that it takes a couple of minutes to carry this out, depending on the wattage of the iron you have.

Mine took 30 seconds of going between the pins to get them all hot enough to remove it easily.

After the connector is out you will need t remove the excess solder with a solder sucker and solder wick.

Make sure you clean off all of the flux before you fit the new connectors.

The new connector is a modular one and fits together making up connectors in multiples of two.

So we will need two pairs for the four way connector.

They slide in with the dovetails keeping them tight together.

Once you have made up the four stack and cleaned out the holes for the connector you are ready to fit it.

two almost together
sliding two together
two fully home
two fully home to make a 4way conn

What I tend to do is to push the connector in – noting how tight or loose it is, ensure you fit it the right way round so you can fit the wires into the connector.

Push it all the way home – if it is really tight then stop – remove it and examine the holes – you may find a little bit of solder left down one of the holes. Clear this out and try again – never really force it in as again you have the chance of damaging the plated through holes and causing a problem of no connection on some pins.

Once it is all the way home, solder one end pin and stop.

Now look at the connector and see if it is still in the right place or has it moved – it is normally trying to fall out at this time as it is underneath the board with no support.

To readjust the connector heat the solder up and once it is molten readjust the connector to its right place. Stop heating the solder.

Check it again and once happy solder the other end pin, and check once more before soldering the rest of the pins.

Make sure you refresh the solder a little on the first pin to ensure that there isn’t a dry joint trying to form due to overheating the solder while adjusting.

Now clean off the flux with flux cleaner, IPA or acetone.

You have successfully replaced the input connector with a 20a one, congratulations.one connector done

All you have to do is to remove the 6 pin one for the heated bed, nozzle and fan.

This one you can try the same, but I found that with the pin pitch and the number of pins I couldn’t get all off the pins molten at the same time, so resorted to the solder sucker and once all of the visible solder had gone removed the connector.

I constructed a 6 way connector out of three pairs and dry fitted it into the holes.

I found that the locking parts on the connector next to the power connector were interfering with the fit, so took a scalpel to them and removed them.

The connector now slid into the holes and was fitted tight to the board.

Turning it over I soldered one pin and checked the connector, this time it hadn’t moved so I soldered all of the pins and cleaned off the residual flux.

You could cut the original connector into a 4 way and refit that, but I felt it was too much hassle and just used all 6 of the new connector.

The wires to fit into the holes are stripped a maximum of 8mm – so I would pick 5mm as a good length.both upgraded

The connector can take a wire size of 0.2 to 2.5mm stranded and 4mm solid, or 30-12AWG.

So you now have a modified ramps 1.4 board with connectors suitable for the job, they can handle 24A IEC or 14A UL – so dependant on what spec you want to use depends on what maximum current it can handle.

Why is this – well it is to do with the allowable temperature rise of the connector, UL allow a 30C rise in the temperature whereas IEC ( vde and imq) allow a de-rating curve of temperature against current and the specs are a little different.

If you have a different way or any comment on this article please leave it in the comments box and I will get back to you.

This has been an article about upgrading the Ramps 1 4 connections, replacing the connectors to suit the Anet A8 3d printer current, preventing melting or fire hazard.

Many thanks for reading

Phil

Solution for Blown Anet A8 Bed Mosfet on Main Board

anet a8 bed mosfetMy Anet A8 bed mosfet has blown up  – what now?

I have been asked about this question about the anet a8 bed mosfet a few times now.

So my advice was to add an external mosfet and use the output of the controller to switch it on and off.

Thanks to GearBest my order of spare main boards was delayed until a few days ago, and my printer is normally on the go – so I didn’t want to strip it down.

So the first thing I did was to run a new main board up with a power supply – to test it.

I was under the impression that you could run the whole board off the usb, same as the mega. But this is not the case you need power to the board from the 12v dc input.

Now getting the computer to recognise the board was easy – with the ch340 driver installed.

Connecting through the serial port at 115k baud the computer recognised the board in pronterface , but the ‘printer’ was not working – it had errors.

You need to connect the two thermisters, one for the bed and the other for the hotend before you can fool the board into thinking it is a working printer.

So with these now connected, I was able to switch on and off the bed with pronterface.

Switching it all off and now connecting the external mosfet as I had described in an earlier post.

Connect the control wires across r42, the gate resistor for Q1 the bed mosfet.

First thing I had to do was find r42, the second was to solder wires wires across r42either side of it.

Being an 0805 surface mount resistor you don’t have much space between the pads of the resistor, but it is possible to solder either side of it.

Note: an easier place to connect the wires is across the bed mosfet – the two legs are the same terminals as the resistor and wider easier method of wiringspaced.

Wiring in the supply to the mosfet board and putting a load on it of a car led indicator lamp – closest thing I had to hand which worked at 12v easily!, I switched it all back on.

Reconnecting the computer I switched the bed on and … nothing- no light – the onboard mosefet switched on but not the external one.

Ok so what is wrong.

Looking at the circuit, the control voltage goes through a full bridge – to make it polarity independent.

This will take 0.6v off either pin – so from the 5v controller output you need to subtract 1.2v – we are left with 3.6v.

This is fed through a 10k resistor (R5) to the opto device to pass current through a led – this in turn switches on the opto transistor, eventually switching on the output mosfet.

The point of this is, that with 12v on the control input there is enough current through the led to activate the device, but with 5v there isn’t.

Damn – what now!

Calculating the current through the 10k resistor with 12v ( (12-1.2- 1)/10k= 1mA) and with the 5v input ((5-1.2-1)/10k= 0.3mA) we can see why the opto switch is not working.

Note the extra 1v drop in the above equation is for the led internal to the opto device.

So working it the other way round – we need a minimum of 1mA to operate the opto device we can use the voltage to calculate the resistor value.

5-1.2-1 = 2.8v

To have 1mA flowing and calculate the resistor value we divide the voltage by the current.

2.8/0.001 = 2800 or 2k7

I am very lucky to have an 0805 resistor kit, so I looked through this and found the closest value was 2k7 (preferred value). Removing the fitted one and replacing it with the 2k7, reconnecting and switchingreplace 0805 resistor the bed on and off it worked.

So if your anet a8 main board has blown its bed mosfet you have three choices.

  1. buy a new main board – be it ramps and mega or standard replacement.

  2. Replace the Bed mosfet(ebay link)– see below for directions on how to do this easily.

  3. Use the controller voltage but change the resistor value on the external mosfet board. resistor kit

Replacing the onboard mosfet easily.

Note: remember these devices are static sensitive – pick up the device and then touch the board with a finger to get both the board and device to te same potential- reducing the chance of it blowing up!

I have just been reminded that you need to know the device number to replace it!
The device is an IRLR7843 mosfet.

Can be obtained  ebay sources in the UK or elsewhere dependant on time scales.

The onboard bed mosfet is located where the designator says Q1. It is under the silver heatsink.

This heatsink is held in place with thermal silicon adhesive.

To remove this heatsink, take a flat screwdriver and carefully lever the heatsink away from the device. This may pop off easily or be very difficult. If you use the board as a lever by the green connectors it is controllable – but be careful you don’t damage the board.

Once this is off you can see the device is held down to the board with two legs and the back pad.bed mosfet exposed

To remove this device easily – carefully cut the legs of the device close to the package.

Use a soldering iron to remove the cut legs- don’t damage the pads on the board.

To remove the main body, hold the tip of the soldering iron against the metal tab at the top of the device and feed a bit of solder onto the iron.

You will see the solder flow onto the tab of the device – when this happens it is ready to be removed.

Use a pair of tweezers to lift the device off the large rear pad and you have done it – congratulations.

All you have to do is to clean up the large pad – make the solder flat – and replace the device with a new one.

To remove the solder from the pad I use solder wick.

To use this lay the solder wick over the solder you want to remove and press on top of this with the soldering iron, you will see the solder melt and flow into the solder wick.

Remove the solder wick from the area before the solder solidifies.

If the solder solidifies then remelt the solder with the soldering iron and remove it quicker.

Remember that this wick is copper and it will conduct heat – so keep your fingers a little away from where you are going to remove the solder. Or get asbestos fingers!

To replace the device

Melt a little solder onto the large pad. And I mean a little.

Place the device onto the pad and heat the tab.

Feed a little solder onto the iron while it is in contact with the tab and the large pad to assist reflow.

When the solder melts then position the device carefully with tweezers – making sure the two legs are on the correct pads, remove the iron.

Solder the two remaiming legs to their respective pads.

Now all you have to do is to glue the heatsink back on with this thermal compound.

And you are done.

Now test the board – without loading it with the bed to start with.

So there you have it – how to replace your bed mosfet and how to wire in an external mosfet if your anet a8 bed mosfet blows!

It sounds complicated but really isn’t.

If you have a go at replacing your Anet A8 bed mosfet and have problems then why not comment in the box below and we can try to sort the problem out.

Thanks for reading

Phil

3d print journal : Polymer Igus bearings

Update to SB1 : replacing your bearings, Igus Bearings

A while ago I wrote a post about replacing your bearings. SB1Anet A8 upgrades : Anet A8 3d printer

In that post I had bought a set of bearings from China, they turned out to be very poor quality.

Even just running them up and down the rod I could feel that they would make the prints even worse than what was already on there. They were lumpy and grinding, I cleaned and oiled them to no avail.

So what to do. Continue reading 3d print journal : Polymer Igus bearings

3d print Journal 10-01-18 : Slicer Vase Mode

Happy new year to you all.Anet A8 upgrades : Anet A8 3d printer

Prior to the Christmas break I was printing with my Anet A8 3d printer.

I had the slicer vase mode set– if you haven’t tried it you must.

Vase mode produces, in some slicers, a continuous spiral – no steps in layers and only one shell thick no infill.

Great for vases!

But people have found that you can print other items, which follow the rules – continuous circuit on each level.

So a mathematical christmas tree and other objects have appeared.

The first slicer I tried with vase mode was KISSlicer.kisslicer logo

You have a lot more control over most things with this slicer and it can be very confusing to start with – it is really frustrating that most of these slicers call the same thing by a different name – just trying to be clever I think but to the end user it is very confusing.

Anyway, I had gone through a certain number of calibrations with KISSlicer and thought I was getting somewhere.

They have model which does not slow your printer down as a calibration piece. Download it here.kisslicer vase mode

So I was getting on with the vase mode ( found by sliding the infill slider to the right in the style tab) and not really being happy with the fact tat it would print like a normal print – with the z axis going up a full level each layer, but with no experience in vase mode how do you know different.

I started printing out the Christmas trees, and found a few problems -like minimum layer time – the printer would, at the top of the tree, raise the print head and wait then resume. The top would then not print properly.

Another reason to look at the sliced file before printing, so I did next time and thought I had cracked it – it was ok until about 1cm from the top where it did the same again, even with the min time per layer set to 0.

so enough of this I changed slicers, I went back to the one I think most people have used Cura.cura logo

Reading through some of the older posts on forums I came across the fact that in cura vase mode was called ‘spiralize the outer contour’ – vase mode is shorter and more descriptive!

Activate it by going into expert settings and click the selection.

old cura vase mode

So I tried a print in this and wow – I sat there for a fair few rotations of the christmas tree, watching the z axis continuously turning ever so slowly the print nozzle never stopping and the filament continuoulsy being fed.

What a joy!

The print – well there was no seam to start with, it was as people had described vase mode – a very thin single layer structure.

And it printed to the very tip with no problems!

I like the idea of KISSlicer and will go back to it in the future, but at the moment I am back with Cura, version 15.04.6 at least.

With the success of this I looked on thingiverse and downloaded a few more vase patterns – I can recommend the vases by  Ferjerez Mathematical creations which if you have scad you can play with.

Some of the vases and bowls absolutely stunning – thank you Ferjerez.

Printing some of the vases I noticed that in the overhangs there were gaps, looking for the answer online I read that this was due to poor machine setup, hmm what had I done wrong?

I had printed a few more things in ‘normal’ mode and came back to this.

Setting the slicer up and saving the gcode I printed another vase and waited.

This time the walls were thicker and it had all worked, even the overhangs had printed properly.blue vase worked ok

Looking at the settings in Cura I had left the wall thickness at 0.8, printed with a 0.4mm nozzle. I didn’t think this was possible, but it did it, over extrusion maybe? But I don’t care it worked.

So I went ahead and printed a bowl from the same pack and again it came out with a thicker wall thickness sslicer vase mode green bowland was able to hold its shape well.

I downloaded the later version of Cura – 3.0.2 at that time and had sliced the same model, I need to sort out the start gcode so it acts the same as the old version and not drag the nozzle across the bed.find it here in later versions

I hadn’t really explored it with this program and updated to version 3.1.0, it loads so slooowly on my PC.

I downloaded another ‘ test your printer’ file by majda107 and h

ad sliced that in the latest Cura, saved it – had a quick look at the layers and copied it across to my sd card.

On printing it I thought something was wrong with my printer – the first layer would not stick and the further the machine got into the print the worse it was.

Using a screwdriver I was constantly adjusting the height of the bed – flashbacks of the old days when my Z axis endstop was loose – nope it still wouldn’t stick.

I happened to glance up at the display and saw the Z height at 0.8mm and thought – that’s strange it should be on the first layer, how come.

Then it dawned on me, my hand slid slowly around to the reset switch on the main board and pressed it.

The print head was slid across to the left and the mess on the bed was cleaned up.

Back to the PC to slice it again – this time untick the ‘spiralize the outer contour’ and slice it again.

Yes I did laugh and wonder at the software engineer who could have added something to the display to say that you are in a ‘special’ mode rather than standard mode. But no they leave you in the dark with most of this. And people wonder why 3d printing does not take off with the masses!!

yes I did check the layer mode more carefully this time and yes it did print more than just an outer shell. I do wonder what it really would have printed if I had left it and the layers had stuck together- would It be a ghost outline of the model which it was going to print?

So if you take nothing else from this – make sure you check that you are not going to print in vase mode when you expect something else!

And increase the wall thickness of vase mode to make your models a lot thicker and stronger.

I did notice when playing around with the later Cura 3.x.x you will need to exit the program and restart it to get the model to slice correctly.

Good luck with your printing. so go and have fun with your slicer vase mode.

Thanks for reading

Phil