3D Printer Design Notes

I purchased a Tronxy P802ma 3D printer off Ebay mid-June this year. It is made with an acrylic frame that is complete junk. I can hardly print replacement parts as fast as they break. This has prompted me to design some new mechanics for the printer and recycle its guts.

I have been experimenting with using a bearing truck for the Y-axis of the printer. I have learned that "skate bearings" (608zz) that are being sold for $3.00/10 pieces are complete junk. I wouldn't even really classify them as bearings. 0.002" TIR. Complete garbage.

The belts that are typically used are 6mm wide "GT2" belts. I bought some generic ones for about $1/meter. I measured that the belts stretch about 0.006"/lb of applied force for a 31" long piece. This could significantly limit my maximum acceleration rates I think my current design will call for about 38" of belt in a loop. I am considering another design where I mount the motor vertically with a very short band of belt and an S-wrap around another singular pulley. This should allow me to get the total belt length down to about 10 inches. 0.003" of stretch per pound of force sounds a lot better than 0.012". Putting the carriage on a diet wouldn't hurt either. Maybe aluminum threaded rods are in my future.