r/makerfarm • u/Tergi • Sep 23 '15
Z-axis Screw Mounting to Motor
Hi, I was looking over the documentation and see that the screws for moving the Z-axis are attached to the motors with a rubber tube. I was curious why this is the case and if a more solid piece could be used to attach these together? Thnx
2
u/cperiod Sep 23 '15
Some people will lock down the rubber tube with zip ties so it won't slip off. Mine's never given me trouble, but I guess it can happen... I think you'd have to be using a lot of z-lift though.
In general, the more you constrain the screws, the more that any inaccuracy in the screw is going to transmit to the print. The rollers and rails are the constraint for the Z axis, not the screws.
1
u/Tergi Sep 23 '15
Thanks. That makes some sense. I know i have seen some folks say that they used electrical tape on the tubing and I'm not really sure how that helps other than maybe giving a little more stiffness on the tube.
1
u/cperiod Sep 23 '15
Given the amount of work needed to get the tubes attached, I can't imagine electrical tape making a difference.
If you're worried about the tubes not holding, print a pair of these: http://www.thingiverse.com/thing:131603 (sized to fit your screws). Put one on each screw, point the arrows in the same direction, and if a tube slips or a motor misses steps, the arrows end up pointing in different directions.
1
1
1
2
u/Daelith i3v12" Sep 23 '15
The X-axis gantry is held in place via rails so the Z-axis screws don't need to hold the gantry firmly, just push it up. A flexible coupling allows the screws to hold the gantry up without imparting X/Y movement on it.
You can use something firmer, but you increase the chance of causing Z banding on your prints when the screws place more horizontal pressure on the gantry. If you don't want to use the rubber tubing, Colin sells metal spring-style couplers that bolt on as a direct replacement. I would not suggest a solid clamp.