Damn I need to change my Z Axiz design. It’s been good and I thought I could fix the remaining vertical artifacts by going to 12mm bearings from 8mm but alas there seems to be more play in them and bushings drag too much. Any suggestions for something that would go in this frame.
Trapazoidal lead screws and solid couplers
What are/were the bushings made of and EXACTLY how much play did you allow?
Can we have a close up of the part you are talking about with any attachments viewable?
You actually might be over-constraining it. All 4 rods need to be perfectly parallel for this to work.
2-3 rods maximum. If you use 4, mount them very close together, or even on the same mount.
@Ed_Kramer I’ve used linear ball bearings and use the 45mm long ones on 8mm shafts. But the most recent machine I’ve tried to increase the shafts to 12mm, I built it with 12mm linear bearings which can twist about 1mm I’ve also built a carriage with 12mm graphite bushes but it’s too tight and doesn’t move well.
I’ve been using this design for years and it’s been good but it could be just a little better. @Stephanie_A I’ve been wondering if I should bring them closer together or further apart. I’ve also thought of doing a 3 point design with 3screws close to a bearing each and 3 stepper motors.
That’s one of the ways you can do auto bed levelling, but make sure you use self aligning bearings.
Then this, it reduces the vertical rods to 2 and 2 bearings are mounted on one shaft the two shafts are linked by 2 25mm aluminum tubes
Hi Micheal, maybe have a look at our youtube videos… we do it with Tslot aluminium and it works well. https://www.youtube.com/user/Motedis
Ok so Ive come up with this, it will have this on both ends of the bed. the motor is shifted to the inside and the bearing and threaded shaft are close together. The two are connected with 25mm aluminum tubes for added rigidity.
The shaft and rod don’t need to be uncomfortably close. I think your issue was more that you had too many rods.
@Stephanie_A Its probably going to be a snug fit. But the alternative is moving the shaft 25 mm to the other side of the frame. I’m printing the 1st parts now. The 1st side should be done in the next 3 hours. I have 3 machines doing a bit each, so it’s going to be a little rainbow of parts but once I know if it will work I can reprint to match as there will probably be a bee changes anyway.
Just assembled the 1st side and it’s looking and moving as expected. Just the last carriage to print and will assemble in the morning. However in need to go get some aluminium tubing to finish it. Will post pics when done and then when printing
There is no cooling fan on yet it’s printing now. But here’s the difference the new z axis made. Same gcode.
Bad news is I now have to print 2 more sets to retro got to two other machines. Atleast i have one more machine that can print some of the parts.
That’s a big difference, well worth the effort.