My only concern with this rigid coupler is of course any radial alignment issues that would not be compensated for.
Idealy the Z axis components should be parrallel to the rails and perpendicular to the X Y surface.
Just need to play some with the mounting of the z components.
Motor mounted first, install coupling with support loose, ball nut loose / not attached to plate.Now tighten support. Check how
perpendicular the screw is to the X y. Rotate the screw by hand using the motors shaft (attached old coupling
to the motor shaft to make turning the screw easier). Check runout of of screw at the end. Move end of screw half of runout and tighten the screw nut. Loosen support and re tighten. Attach motor. Should be darn close to being alligned.
You can work top down or bottom up or even work out from the middle.
Writing this is like try to tell someone how to tie their shoes!
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How I do it for a short rather rigid axis alignnment:
I use torque indicators and they are very accurate.
1.Preload the support bearing. Check torque with nut finger tighting of nut.
Continue tightening to add preload and check torque. As preload increases the
torque required to turn the bearing increases. If the motor is say 100 in/oz
you don't want to use up 50% of you motor torque. You want to minimize the torque
and also have min axial play. Axial play results in backlash.
There is no such thing as no backlash.
Total backlash is the sum of each components backlash.
If you isolate a component you can measure it's backlash.
Note both the torque setting and the backlash at that setting.
2. Measure torque required to turn the nut. Note it and measure any backlash.
2.The support bearing is installed / mounted and rather closely alligned to other axes.
3.The nut is installed / mounted.
You will find the torque ( nut + support) is very close when the nut is located at the
end, middle, and close to the support if installed correctly. Note any increase in torque.
The increase will be due to axial misalignment and whatever attached load is being moved
due to friction and weight.
4.Install the end support when the nut is close to to the end support. If fixed type do step
#1 for it,but, usualy it is not.
5.Check total torque when axis is near fixed support, middle, and at end of longest travel
near the other support. All torques should add up to individual torques.
6. Re calibrate axis after motor is attached.
Now nothing is ideal, for instance, the screw may be not be straight. So you need to tweak
each component along the axis travel.In the case of a vertical installation it may just right
but the axis travel is not parrallel to another axis.ETC!
In the end one will have minimised backlash and the torque to move the axis having a
a positive affect relative to velocity, acceleration, and repeatability and component wear.
There are other way to do things.......and surely I missed something......
FWIW
RICH
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