[kostas1]

Hi, I mounted the coupling on the ballscrew and motor and as you can notice in the videos, there is some noise from coupling not (maybe) being properly mounted on both ends but it is quite difficult for me to mount it without stretching the spirals of coupling.

Do you have any idea/trick for doing this?

Also, does the coupling needs to be sliding easily to the ballscrew and motor shafts? I needed to hit with a elastic-head hammer in order to insert the motor shaft into the coupling and then screwed the bolts of coupling to each shaft respectively.

??????0002 - YouTube
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Thanks.

[Al_The_Man]

Appears to be excessive misalignment of motor and driven shaft?
Al.

[kostas1]

Appears to be excessive misalignment of motor and driven shaft?
Al.

Hi, you mean that motor is not aligned correctly with ballscrew?

Actually this the type of coupling I use:

http://t0.gstatic.com/images?q=tbn:A...yWwN8vhRUYm5XA

Also, another important note is that when I try to insert the motor shaft and the ballscrew shaft into the coupler, I meet some difficulty and i need to hit it with elastic hammer or push it very very much....is this normal?

[Al_The_Man]

Excessive force should not normally be needed, Is this an aluminum you are using?
For motor to B.S. a Stainless version should be used.
An aluminum type, especially with that apparent misalignment is not going to last long.
Al.

[keebler303]

Looks to me like the motor shaft is bent and the motor is poorly aligned to the screw.

[kostas1]

Excessive force should not normally be needed, Is this an aluminum you are using?
For motor to B.S. a Stainless version should be used.
An aluminum type, especially with that apparent misalignment is not going to last long.
Al.

Yes this is an aluminum coupling.
The fact is that even if I align it correctly (having the spirals being equally distanced each other), when I move the Y axis, it is slowly misaligned and make this noise.

[kostas1]

Looks to me like the motor shaft is bent and the motor is poorly aligned to the screw.

Maybe this is because my video was taken with mobile. However, I cannot see some bending or misalignement.
Thanks.

[keebler303]

The top half of the coupling, in your second video, seems to gyrate. If it was simply misaligned, it should spin true. That gyration makes it look the like the motor shaft is bent. It's hard to tell from your video.

If you get it aligned and then tighten everything down, how does it slowly misalign? This doesn't make sense.

[kostas1]

Hi,
I think that I fixed this issue:

Please see below.

CNC 1m X 2m - Part 4 - YouTube

[keebler303]

Looks much better!

[kostas1]

Hi,
I am dealing with another problem right now in Z axis. When I screw the bolts (please see yellow circle in the first picture), then the ballscrew can hardly turn, but when I unscrew them a little bit, then the ballscrew turns ok.
These two bolts are screwed on the small aluminum piece(please see the 2nd picture in red circle). Notice that when I insert the system(in green circled) on the rails, the small aluminum piece(in red circle) is smoothly osculates(touch) the aluminum plate(in green circle)


Attachment 208408
Attachment 208410


Do you know what might be wrong when I screw these 2 bolts?
Thanks again.

[wendtmk]

Sounds like your screw bearing block holes are not concentric. When you tighten those two bolts, you are pulling that block out of alignment with the blocks that are holding the screw. You might want to try shimming that bearing block out from the plate.

Mark

[RICHARD ZASTROW]

Or (1) the surface of the block holding the ballnut to the Z-axis is not parallel with the bore locating the ballnut. (2) The distance from the mounting surface of the block holding the ballnut to the bore does not match to the ballscrew. This would cause the ballnut to interfere with the ballscrew. This would be more easily noticed with the ballnut closer to the motor end of the ballscrew.

Dick Z

[kostas1]

Or (1) the surface of the block holding the ballnut to the Z-axis is not parallel with the bore locating the ballnut. (2) The distance from the mounting surface of the block holding the ballnut to the bore does not match to the ballscrew. This would cause the ballnut to interfere with the ballscrew. This would be more easily noticed with the ballnut closer to the motor end of the ballscrew.
Dick Z

So, do you suggest that I could try shimming between the block holding the ballnut and the aluminum sheet?
Thanks...

[RICHARD ZASTROW]

I would suggest making sure the plate you attach the ball nut mounting block to is parallel to the ball screw. Then I would determine the actual dimension from that plate to the centerline of the ball screw. Next, I would determine that the ball nut bore is parallel with mounting surface of the mounting block and the exact dimension from that mounting surface to the bore. Then if the dimension needs adjusting by removing surface material it could be milled or if it needs shimming to bring it in position that could be done. If shimming, make sure the shim is parallel so you do not create another problem.

Dick Z