In May, Instructables user DesktopWorkshop released the design for a 3D printed pneumatic actuator. S/he has followed up this month with the unveiling of a much more complex creation: a complete pneumatic motor. Unfortunately, the printed pieces have not yet arrived and so there are no photographs of the prints nor a fancy YouTube video showing it in action. However, given the nature of the 3D print world, I wouldn’t be at all surprised if that’s remedied rapidly either by DesktopWorkshop or the army of print warriors at large.
A pneumatic motor generates mechanical power by expanding compressed air. Experiments with compressed air engines have ranged from powering handheld devices to the movement of trains across countries. In 1863, the first mechanically powered submarine was driven through the waters off the coast of France using a compressed air engine. Keeping true to the French affinity for pneumatics, the Tramway de Nantes became the first fleet of trains to be powered by a compressed air Mekerski engine in 1879.
To date, the use of compressed air in planes, buses, and automobiles has remained limited to amateur explorations or back room speculation. The primary applications for pneumatic motors have been in the powering of handheld tools and for use in situations such as supplying power for use in coal mines where the traditional combustion engine would present a much higher hazard risk. But just because you’re not trying to develop the next great flying machine doesn’t mean that you can’t enjoy a little compressed air mechanization.
DesktopWorkshop introduces the creation on Instructables:
“I’ve been working on creating a 3D printable engine for a few months now and this project combines the best of all my attempts. The upper section contains a valve system which allows the piston to extend, only after being depressed (ie on the ‘upstroke’), letting the engine run both forwards and backwards and reducing the amount of tubing to a minimum.”
A single cylinder version is available for print as well as the full V2 engine, the primary difference being that the V2 requires printing two cylinders and the structure within which they can work together. The rubber seals are created using the dramatically named Oogoo, from Instructables member mikey77, created by combining universal sealant and cornflour (something that I am convinced was invented in some horrified parent’s kitchen, but that’s another story), although conceivably they could be addressed using o-rings as well.
“The seal mould will produce a thick 0-ring and the actual piston piece is pushed into the piston mould, containing the rubber mix, to produce a ‘rubber cap’ that will form an airtight seal once assembled,” DesktopWorkshop explains.
The tutorial guides the user through the steps from print to assembly and promises nothing less magical than a working pneumatic motor. Learning from the errors of hubris committed by many inventors, DesktopWorkshop remains humble and recognizes that there will always be improvements to be made:
“I’m still waiting on my prints so no pictures of a working model yet, but I should have them in the near future. It is recommended you either print a flywheel or add a small, offset weight to the end of the crankshaft for smoother motion.”
Have you considered printing out and assembling this motor? Let us know in the 3D Printed Pneumatic Motor forum thread on 3DPB.com.