Talking with blokes in pubs – 3d Printing

OK, so one of my hobbies is “going to the pub”. As I happen to be on holiday, and living less than 100 yards from a pub (well, really a hotel bar) then it is natural that I have been in there a few times. It’s also natural that I should make the place my “last port of call” before going home to bed. Go out, visit a pub (or two) in the town, drop in at on the way home. As a result, I’ve become friendly with the owner, and a couple of the regulars.
I knew that one of these “regulars” knew something about software and engineering and was from the North-East of England, where I worked a long time ago. I thought that he was in Fife on business. It turns out that he lives there. He works nearby for a company that makes surgical devices among other things. He also makes a lot of use of 3d scanners, printers and CAD (Autocad, Solidworks and others).

He told me a number of things that I did not know about 3d printing. Here we go:

  • 3d printed ABS (I think that is what he said) are approximately 80% of the strength of injection moulded parts.
  • 3d objects can now be scanned accurately with hand-held scanners, rather than a turntable scanner. Presumably some clever software compensates for the operator not holding the scanner steady. 
  • The accuracy of scanning and printing is now about 0.1mm, which is adequate for surfaces which are not touching other things or are going to be machined. 
  • Shapes which would be unstable during construction (for example, large overhangs) can be made by constructing in two materials. One material (which he said was like “sugar glass”) is used as scaffolding to support the real material and then dissolved away. This is rather like “Lost wax” or “Investment casting”, except that the temporary material is around the shape being made, rather than part of it.
  • This technique can also be used for making parts which are going to interconnect, could be moving parts. You design them, then interconnect the 3d models, and then use the filler material to fill the gap between the interconnecting parts. Finally, when the parts are finished, you dissolve away the filler and, “hey presto” the two parts are connected or interconnected. No further assembly is required!
  • Finally he told me a little about commercial 3d printers.

I’m going to try and “bump into him” next week. I’d like to add him to my list of contacts.

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