Notes on 3D printing

As you may know, I am using 3D printing for my cBAM project to create some impossibly complex shapes that can be easily reproduced with very high tolerance on angles etc. My little microscope has now gone through about 7 re-designs since I started, and with each one I’ve learnt more and more about 3D printing and what it is and isn’t capable of.

As I type this, I am waiting for feedback from the very helpful people at 3D Creation Labs on my latest design but while I wait, I thought it might interest people to know what I’ve learnt so far…

  • With only a few hours practice you too can 3D model a flat piece of plastic
    With only a few hours practice you too can 3D model a flat piece of plastic

    3D design is easy – Prior to this project, I had some experience doing 3D drawings for simple medical devices, but compared to most designers I was a massive n00b. But once you understand the software, building 3D shapes and structures is relatively simple and you can create almost anything you can imagine without needing to be a graphic designer

  • 3D design is hard – Unfortunately, as pretty as things might look, making them ‘structurally’ feasible is another matter and designing a shape that won’t immediately break/bend can be a headache. My advice is “when in doubt – add more plastic” which seems to work (pro tip)
  • You can download 3D designs from a repository – People love open source, and 3D printing is no exception – loads of designs are freely available online for you to send to a printer. If you don’t have a 3D drawing program (Google SketchUp is free so you have no excuse) then this is a great place to get and even customise cool designs. Of course, alongside the altruistic open source community there are also places to buy amazing models and inevitably places to ‘share’ models via a pirate bay like index.
  • Support material is a thing you need to pay for – I assumed that in 3D printing you were essentially paying for the volume of plastic useless and the time on a 3D printer – actually you are also paying for a second support material. This is the stuff that holds the plastic in place during the printing process, otherwise the model might move or distort before the process is complete. The quote I got for this was that the support material costs about 50% less than the actual plastic< (which is pretty pricey).
Image is originally from Tech Life click to go read
This shows the support material required to make a small model of a mongoose dog robot dog [image from Tech Life]
  • Direction matters – It never occurred to me, but the orientation of the object during printing makes a big difference to its strength in 3D printing because 3D printed objects have ‘grain’. As each design is built one layer at a time, this grain can create fault lines along important joints – and that weakens the model. This is where using a good 3D printing company comes in – they will look at the design and choose the best orientation.
You can see each line/layer of plastic as it has been deposited
You can see each line/layer of plastic as it has been deposited
  • There are lots of options – When I started, my idea was to get a thing printed in plastic – which is adorably naive. When designing a 3D model you need to think about what printer you might want to use to print it as they all have different resolution, tolerances and even more importantly – cost. Then you need to think about what strength of plastic you need and even what kind of properties it needs to have (thermal stability etc). Essentially, within reason if you want it and can afford it, there is likely a 3D printing solution out there. Of course if you don’t know much about these choices then you can use my method which is…..
  • Dave at 3D creation labs is very patient – My entire learning experience with 3D printing is the result of me e-mailing designs to Dave who then looks at them and sends back a long list of reasons why my clever features will break/fall off. At this point I assume when he sees an e-mail from me he opens up his text book on ‘101 mistakes in 3D printing’ and starts ticking them off as he finds them…

I’ve still got some ways to go with the design – even if (and that is a big if) my current version works, I will still need to round some edges and make it look nice and I’m sure in doing that I will introduce plenty of new problems. But all this has made me seriously consider getting a Maker Bot (~£1,500) and trying it myself – although I think my friends/relatives might get annoyed when all their presents are made of plastic.

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