threads thread

[shortbus]

I'm planning on making an rc car, engine and all. I'm curious about how well printers print threads on a small scale. Should I print the threads or tap drill them myself?

[Geoff]

I'm planning on making an rc car, engine and all. I'm curious about how well printers print threads on a small scale. Should I print the threads or tap drill them myself?

No, tap them yourself.

If you are printing at an 0.1mm layer height which is about the best you will get with these machines.. then if you print for example, an M3 screw and threading, lets say M3x10 for a stock size.

Your 10mm of heigt will be made up of 0.1mm layers, so that would be 100 layers to make the screw (taking ages) and probably the same if the thread is the same height.

Now,look at your thread width - 3mm.. to get a printer to print a nice round thread at 3mm wide, even at 0.10 layer height is hard. Too fast and the circle shape doesnt form, too slow and the thing melts under the nozzle.

so... while it is doing these 100 layers of 0.1mm to make the long section of the screw it also needs to shoot around a 3mm wide circular shape all the way, which is pretty tricky. I can't say I have ever printed any threading thinner than 5mm successfully that I would actually use in a practical sense.

[jfkansas]

Actually most RC cars with molded parts don't have any threads at all. The screws used make their own threads and they stay in better like that.

Pay attention to your print direction. If possible you want your screws going in perpendicular to the layers. If you go in parallel to the layers the parts can split.

[shortbus]

Thanks Geoff that was very helpful. It will save me a lot of time in cad.

Thanks for the tip jfkansas. I'm actually planning on making the engine (I'm going for a v8 if its possible) and yhe frame (if I can do it cheaply) out of metal and the rest will be plastic.