Tool Change X Shift

I use a 1000mm XCarve with the Dewalt 611 and precision 1/8" collet sold here on inventables. When I go to switch out the bit with the red handled tool provided, the X carriage has a tendency to shift as I overcome the static friction of the tightened collet. The steppers are locked but the abrupt loosening of the tool overcomes the holding torque. This causes problems with 2+ tool carves as I have to find XYZ home again, every time there’s a tool change.

How do you all do tool changes? Do you have this same issue? What can be done to address this issue?

Here are some things I’ve tried to address this issue:
Carving a hole with the first tool so it’s easier to find home again isn’t as accurate as I’d like.
Home the machine on the end stops, move a specified distance to the work-piece home, record said distance, then repeat the process when a tool change happens. This method is reasonably accurate, but sometimes recording work-piece home can be difficult as fine adjustments are needed during the first setup.
Overall, these methods can work but takes too much time in my workflow.

Any and all advice is welcome! Thanks!

What about installing homing switches?

I should have mentioned, I do have homing switches and they take just as long to use as rehoming off the end/hard stops and give potentially less accuracy.

Maybe could one adjust the position homing switches for each work piece?

Invest in better, higher precision switches, and increase your seek and feed rate :slight_smile:

My work flow, power CNC up, initiate a homing cycle while I prepare the other stuff. Done.
(At max my machine home in less than 30s)

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That sounds like what I do except I record what movements/distances I make from the homing switches to get to my work-piece home. This allows me to repeat the homing cycle to work-piece home when I tool change.

Any tips on what “seek” rate you’re running at?

I make the xc home location my 0,0,0 location on my drawings. After a tool change I home the XC and then reset the Z axis to the top of the material I’m cutting. I have been told ,and read here many times, that the 4th dip switch can be turned off on each axis on the controller to provide a more secure motor hold. I haven’t been inclined to disassemble the controller that far to get to the board to do that, so I just compensate on the drawings. You can adjust the homing speed in the $$ parameters I think if you are going too slow. You can also jog close to home and then hit home, which is faster. $25 is the homing see rate in mm/min. You have to be carefully you don’t break the switch by going so fast though.

No need, work zero is stored and preserved (untill changed) :slight_smile:

For instance, in Easel, click “Use Previous Home” for the 2nd stage instead of “Confirm Home Position”.
(Z need to be reset prior to the 2nd stage)

So whenever you think you have bumped your machine out of sync, re-home and click “Use Previous…”

Edit - My feed/seek rate is set to 2000 and 250mm/min.

Did you change your gcode and flip the switches in your controller to lock your motors?

My 2 cents - if you are truly locked but still managing to move it during bit changes, perhaps you are over-tightening. You really don’t have to crank it down hard to securely hold the bit. Just firm. I know this is subjective but other than trying to rig up a torque wrench I am not sure how else to describe it. Just lighten up some and see if it helps.