Making it easier to print 3D objects

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Ultimaker snowflake being printed

Hannah Wray recently hosted a workshop at our ‘Science of 3D Printing’ event at Google campus in London, May 2014. This post has been kindly written by Hannah to explain a little bit more about her work. Hannah is undertaking a Masters at Cambridge’s Institute for Manufacturing, studying how people learn about 3D printing.

The problem my research is trying to tackle is that people start out enthusiastic about 3D printing but then struggle with printing an object for the first time and get disappointed. 3D printing has a set of rules to follow to design the best objects, things that are easy to print. These are not obvious to people without experience. So beginners are stuck printing things that other people have designed, or repeatedly failing before they can work out the rules on their own. These rules include things like the 45° rule for overhanging surfaces. This rule states any surface tilted at less than 45° to the horizontal will get rougher and eventually need support material to hold it in place while it prints. This support material can be broken away once the print is finished, but it leaves behind a rough surface. So if possible when designing objects to print, smart designers make sure there aren’t any surfaces tilted like this.


Series of pyramids printed to demonstrate the 45° rule.

By talking to experts at 3D printing and looking at a lot of articles written about the rules, I put together a set of benefits and constraints of 3D printing. People need to think about these before they design objects to be 3D printed, to make sure the objects are well-designed.

Constraints

  • The different 3D printing options
  • Post processing and surface finish
  • Time taken to print
  • Making detail stand out
  • Need for support material
  • Wall thicknesses
  • Clearances
  • Stopping warping

Benefits

  • Complex shapes
  • Nested parts
  • Moving parts
  • Material complexity
  • Personalisation

My project involved interviewing a lot of people about their experiences to find out how they learned the rules and what they struggled with most. I spoke with a lot of Makers and teachers, visitors to Maker Faire UK, and people from my own local hackerspace, makespace. Through the interviews, I found out some interesting things.

“I think 3D printing is a valid thing in and of itself, but in our community – the maker community and hackspace community – 3D printing isn’t about 3D printing, it’s about building a 3D printer.” maker Dominic Morrow.

“I do spend more time trying to fix the printer than printing things.” Colin, Newcastle Maker Space

“Maybe the point of 3D printing as it stands is not that it makes lovely parts (mostly it doesn’t). The point is that it is a medium which satisfies the urge to make, and it is one which has a very low first step, so it is a very accessible way to start making.” maker Richard Sewell

I also reviewed a set of 3D printed projects by younger students from my own university course, to see which of the rules they found hardest to use. Then I put together a workshop session based on the rules that were understood least, to help teach people to improve their designs. I held a version of this workshop at the Science Rewired event. First, I asked participants to design an object to be 3D printed, giving the example of a phone case for inspiration.


Phone case example drawing shown to students

Then I gave them a half hour talk about the different rules I’d found, with lots of pictures and example models that were passed around (including the pyramids above).


Example slide from the talk, on personalisation (one of the 5 benefits of 3D printing) – a family tree personalised by Rich Moir

After the talk I had the participants fill in a questionnaire about how well they thought their designs would work to be 3D printed, and asked them to try making new drawings to improve their work. Other academics have already tried some similar things, but with professional designers. One paper I found talks about how showing designers a ‘Design for Additive Manufacture’ database with examples of well thought out 3D printed objects helped them to design better.


A salt shaker designed before and after viewing the Maidin et al (2012) design feature database

So, how well did the workshop succeed? Sadly I can’t display any of the ScienceRewired ‘before and after’ drawings here, because I don’t have the permission of the participants. But it seemed to go well. I analysed the drawings and the questionnaires, working out where participants had understood the message of the talk and where they still were uncertain. Some participants added notes to their drawings, showing they had taken the messages of the talk. Others talked to me afterwards and discussed how they would change their designs to make sure they would be printable. Some rules are still misunderstood – especially the ones about post-processing (painting etc). This seems to require a more hands-on approach, perhaps a session where participants can sand and paint 3D printed objects to get an idea of what the effects are and what it’s suited for.

The interactive workshop format seems to be good way to teach the rules, but it needs more testing on different groups of learners to be sure. The slides and lesson plan of how to give the talk should be going up on Ultimaker’s CREATE Education Project soon. Hopefully if the workshop is used by more teachers they can tell me what’s good about it and what needs to change, to make it a better learning tool.

I was pleased to have so many enthusiastic participants in the workshop, and want to thank Science Rewired again for inviting me. There’s a lot more interesting research in this area to be done, and I hope my work can contribute. If you’re interested to find out more or have some comments to make on the project, feel free to get in touch with me at hw364@cam.ac.uk

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