Well, I don’t feel so special now. I was so happy with my little 3D printer and then Monash University go and print something close to my heart – a working jet engine! (link here) Damn – that makes my printer look like a dinky toy. Oh that’s right – it is!
I have been pretty sceptical that cheap 3D printers are even slightly useful. That is until I ordered one out of frustration.
A while ago I decided it would be a good idea to modernise my mighty Lycoming 540 engine for the aerobatic plane to give it a bit more vertical penetration. That included Motec M1 engine management, tuned length manifolds and exhaust, custom pistons and cam etc. To really complicate the project – I thought it would be a good idea to totally redesign the valvetrain. Just because I can doesn’t mean I should!
The CAD design was obviously the easy part and a lot of fun trying to optimise such an archaic design. It didn’t take long to draw up some roller rockers, solid lifters, tapered pushrods, valves and guides etc. The problems started when it came to validating the design. There is no substitute for a working prototype to test the geometry but trying to find a spare moment to fire up the CNC to make a test rocker pushed the project onto the backburner for way, way too long. Heck – I was getting worried that the earth was going to run out of fuel before I found the time.
Enter the 3D printer…
I am really flabbergasted how much time it has saved. Quite frankly, I feel a bit silly that I didn’t already have one! Within fifteen minutes of it arriving, it was printing prototype number one. Within that first day it had printed the prototype number five, the final rocker which allowed me to get the valves and guides ordered. No wasted time trying to work out how to hold a billet of aluminium in the CNC, no swarf, no mess, and no time wasted when I could be working on customer cars. 
It also saved me from ordering the wrong length valve due to a measurement probe offset error that I probably wouldn’t have picked up if I didn’t have a little plastic printed valve to compare to a Lycoming factory one. That error would have cost me more than the printer and put me in a really bad mood for a really long time.
I think this printer and I are going to get along just fine. I needed a 90 degree backshell for a wiring loom I was making yesterday. I couldn’t find one commercially available. No problem. It didn’t take long to whip up a drawing and send it to the printer. The result was printed in ABS plastic which is the same material as the one that came with the plug.
Now I just need a 3D scanner so I can make a bobble head to stick on the dash of my car…
Oh, and now I need to find the time to go and make the optimised roller rockers on the CNC.