Tool height fluctuation during operation

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reanielaw
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Joined: Wed Jun 28, 2017 11:40 pm
Model of CNC Machine: Pacer 4010

Tool height fluctuation during operation

Post by reanielaw »

Hey everyone,

I'm running a CNC router (Pacer 4010). I have been noticing lately that my tool height has been increasing and decreasing in height as I'm running a program. I thought my waste board was uneven but when I go to tool tip my bit, I'll be getting a lower or higher measurement than when I first measured it in the start of running my sheet. I'm not sure what would cause this. I thought maybe my bit is slipping a little bit inside the collet but I checked that and it was nice and tight. Could the cone be slipping down a little bit in the spindle? Has anyone heard of this and would happen to know the possible cause?


Thank you

ger21
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Re: Tool height fluctuation during operation

Post by ger21 »

You mean the toolholder in an ATC? If it moved down, you'd know it immediately.
Are you sure the workpiece isn't moving?
Gerry - http://www.thecncwoodworker.com

4DThinker
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Re: Tool height fluctuation during operation

Post by 4DThinker »

Check the coupler between the Z axis stepper and the Z drive shaft. If it is just a little loose then it may be the cause of your Z height woes.

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martin54
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Re: Tool height fluctuation during operation

Post by martin54 »

While you are checking couplings you are as well checking the spindle is secure in the mount & the spindle mount isn't moving at all, how old is the machine ? have you checked for backlash or binding of the axis ?

garylmast
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Re: Tool height fluctuation during operation

Post by garylmast »

An old collet could be and probably is the culprit. If that's not it, the stepper motor for the Z axis could also be the problem. If you are not losing height when using different sizes of mills (different collets), the stepper motor would be the next thing I would check. If that is, a quick solution could be adding springs to help hold the weight of the spindle. If that don't work, replacing with a higher torque stepper motor would be suggested.
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