Rigidbot CoreXY v2

Rigidbot CoreXY v2.

This is a conversion of moving bed Rigidbod printer to CoreXY machine and using 10mm carbon rods and bushings for X axis.

Version 1 is published here. Please read the instructions and parts list. The differences in the two version include the option to replacing the X 8mm steel rod and bearings with 10mm roll wrapped carbon fiber rod and brass bushings. The steel rods can also be used with this version - use the 10->8 mm spacers to make up for the smaller rod.

Brass Bushings: The bushings are quite cheap and are copper plated steel, but have a thin graphite lining, which provides smooth gliding surface. The graphite will wears out over time, and doesn't damage or scar the carbon fiber rods. They have been working well for last 6 months of use and the intention is to periodically replace them (maybe after a year of use). The measured backlash in X axis is about 0.05 mm. I find that adding a drop of Superlube Precision Oil with PTFE helps reduce friction.

Carbon Fiber Rods: The CF rods should be roll wrapped and can be bought from ebay/aliexpress. Usually the rods diameter varies over the length of the rod and needs to be carefully wet sanded down to precise fit. This is the most tedious part of the build. See a helpful video from tech2c on how to do this - youtube watch?v=0Pg-L1pQ6qU (but sand them wet. Carbon dust is poisonous).

Igus Bushings: I tried 10mm Igus bushings on the CF rods, but the backlash on X axis was more than 0.15 mm. Polymer bushings work when the machine is quite stiff and perfectly aligned.

Idlers and Pulleys: Use only Gates. Minor eccentricity in cheap idlers add up and show as wobble in XY joiner and carriage. I found hardware bought at this store to be of good quality.