In the original design a joint that allowed the delta arms to pivot along two axes was purely a bush fitting, which would eventually loosen and create backlash. I decided to make a version that incorporated small bearings to increase the smoothness and prevent backlash.
These parts that I call “bearing joints” were going to be a real trouble to make on my CNC router and by trouble I mean I couldn’t have made them. The shape was too complex and would have required 4 sided machining.
I went in search on the reprap forums for a fellow New Zealander who could help me out. I ended up meeting Bert from Protoneer.co.nz. He was able to use his new UP 3D printer to print me out 16 of the final design of the bearing joint.
Bert also helped me to evolve the design and make the end printed result much stronger and viable for the role it would need to fill. If you’re in NZ then be sure to check out his website linked above. He has great products and is a thoroughly nice guy and a pleasure to deal with.
After press fitting the four 3x6x2.5 bearings into the bearing joint I installed it on the carriage. The joint is squeezed between two M3 washers to tighten up any slack and hopefully prevent the system from developing any backlash.
I cut out a test delta arm on the CNC from 10mm white HDPE and attached it to the bearing joint with an M3x20 button head bolt.
The movement was tight and free of backlash while the bearings supported very smooth movement even when I applied heavy force while moving the arm around.
In conclusion I am very happy with these bearing joints. I think they will give my delta 3D printer very smooth movement and will (fingers crossed) give me a no backlash delta system that rarely requires maintenance.
So next up will be some photos of my Makergear hot end and my completed top bearing blocks with limit switches mounted.
In other news… After realising some errors with my dimensions and issues with my CNC router I had to redo all the delta components (the platform and the three carriages). Thankfully I’m all finished with the machining and now in the process of epoxying the parts together.