Engraving small font - the bit digs deeper and deeper as the job goes on. 6040z

[magicniner]

If it's a clamp which holds the motor cylinder cut a strip of beer can to line the clamp and "shim" it tighter,

- Nick

[xoneeleven]

Here is a YouTube video of the issue, and I have attached a photo.


http://www.youtube.com/watch?v=vKDzOAWZZvk&feature=youtu.be

[xoneeleven]

We will certainly try that route.

Thanks

[cropwell]

It looks to me that the leadscrew for the Z axis is not clamped at one end (it should be floating in one bearing and fixed in the other)
Here's a a couple of photos to show what I mean.



It looks as though your machine is using the stepper motor to 'fix' the Z screw. However the type of coupling you are using negates this option.
It is bad design to use the thrust bearings in a stepper and you should post some pictures of the leadscrew bearings at each end for us to check this out.
The 'Oldham' coupler you have is not designed to resist being pulled apart, which is what is happening and the whole leadscrew is slipping downwards.

[cropwell]

If it's a clamp which holds the motor cylinder cut a strip of beer can to line the clamp and "shim" it tighter,

- Nick

Nick, I think it is the leadscrew bearings that are design deficient.

Rob

[Clive S]

Here is a YouTube video of the issue, and I have attached a photo.

As Rob suggests I think you have a problem with the bearing holding the screw in position the motor should certainly not be doing that job. It will further damage your machine without sorting this problem out.
Take the motor off and see if you can check for end float in the screw

[cropwell]

Take the motor off and see if you can check for end float in the screw

It isn't end float. More like end sink. That has got more slop in it than an old Beetle crankshaft. I would bet that there is no fixed bearing at all.

Nick - I agree with you the OP was confusing us talking about the Z Motor.

Happy Days !

Rob

[magicniner]

Rob,
Re-reading I should have worked out that it wasn't the spindle motor but it was the only thing I could imagine moving on a halfway logically assembled machine :-(
I suppose all the vendors of ball screws should have a recommended shopping list of Ball Screw, Ball Screw Supports, Ball Nut and optionally Motor Mount, Motor Coupling and Motor, with a brief explanation of how and why, the market has clearly moved to a point where there is no research prior to shopping,

- Nick

[xoneeleven]

The Chinese vendor sent me a reply to an email that I sent them telling them about the issue.
Their response was:
"Dear friend.
Please can you buy such a coupling to change it. The problem will be solved then. This coupling is cheap only about 3usd. Can you get it in USA local? If yes. We can refund you 10usd. Then you can buy it. If you can not get it local. We can ship you 1pcs. It will cost about 12days. Please check if ok for you.
Waiting for your confirmation. Thanks a lot.
Nice day."
___________

I am unsure about what coupling I can buy in a hardware store to fix the issue.
Does anyone else have any recommendations on where to get similar couplings?

Thanks...

Mark

[sinnsvak]

You didnt take a look at the fixed end of that ballscrew, which is on the bottom. There are two bearings on either side of the bottom plate, secured with a 17mm locknut on the ballscrew. The top bearing near the stepper motor is the floating end.