Tag Archives: 3d cad

 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.

Finally…

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…..you 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

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.

[poll id=”2″]

Thanks for reading

Phil