Centroid Community CNC Support Forum

Hello again great folks of this forum!
I've been having an issue and it's getting annoying. I've set all tool offsets and they save and operate great until I turn off the machine for the day and come back in the morning. I start up the machine and use tool 1 to set 0 for x and z. My other various tools will be off by 0.01" to 0.03" and I have to re measure all the tools. It's a real pain for drills and boring bars...
I've checked steps per rev and I'm 0.0001 accurate as well as set my backlash and those are, what I feel, within tolerance. The table itself is sold and all the tool holders are very ridged and don't move.
I've searched the forum a little and haven't found anyone with my exact issue so I'm assuming it's user error or machine error.
What else can I check? I don't have much hair left to pull out!
Thanks

Do you have info/links on the tool holders you are using? They are exactly what I'm looking for my lathe.

No immediate ideas.

If you double-check tool positioning (e.g. with an MDI Tnnnn / G0X0Z0.1) after running for a while, but before shutting down, are they all still on position?

If you make note of the numeric values for your tool offsets (both geometry offsets and wear offsets) before shutting down, then check them when you start back up, have they changed?

When tools are off, are all of them off by roughly the same amount and direction? Or is it scattershot?

I know nothing about Lathes. What is your Parameter 3 set to?

12.3.5 Parameter 3 – Modal Tool and Height Offset Control
Bit Meaning Parameter Value
0 Tool and Height Offset numbers, T and H, will be reset upon job Reset upon job completion = 1,
completion (and not remain modal and active between jobs). Remain modal between jobs = 0
1 Unused for Lathe. This bit should be set to 0. Should always be = 0.
2 Tool Height Offset Retention option. This option prevents the Turn on Tool Height Offset
current tool height offset from being turned off when the user enters Retention option = 4, No = 0
the Tool Height Offset menu. Additionally, this option will cause
the H height offset to be set to match the tool number when an Auto
Tool Change is performed (via F7 ATC) in the Offset Library.

slodat wrote: ↑Thu Dec 03, 2020 9:15 pm Do you have info/links on the tool holders you are using? They are exactly what I'm looking for my lathe.

I’ve found tormach has the better prices on the basic holders but if you search for ECI gang tool holders, there are plenty of options. Posi locks are solid and you can set up gang plates for different runs.

cncsnw wrote: ↑Thu Dec 03, 2020 9:55 pm No immediate ideas.

If you double-check tool positioning (e.g. with an MDI Tnnnn / G0X0Z0.1) after running for a while, but before shutting down, are they all still on position?

If you make note of the numeric values for your tool offsets (both geometry offsets and wear offsets) before shutting down, then check them when you start back up, have they changed?

When tools are off, are all of them off by roughly the same amount and direction? Or is it scattershot?

I’ll run these down and see what turns up. Thanks for more ideas!!

Ok, after measuring and testing and restarting it multiple times I'm still at a loss. After restarting Acorn, Each tool is off by a different measurement, each restart cycle does not produce the same error. We are only talking .005-.012" difference but if I don't re measure and set the offsets, it's off by some amount after it's restarted again compounding the offset error.
Could this be due to cheap home switches? What about interference in wiring? All of my wires are insulated.
I checked and re measured my turns calculation.
Once it's dialed in and running it will reproduce .0002 accuracy according to my DRO. I called it good at .0002 with the Lash Comp.
I've verified this with my DRO and a Mits. .0001 Dial indicator.
Anyone have gremlin bait? How big does my gremlin trap need to be?

Dbean wrote: ↑Sat Dec 12, 2020 8:06 pm Ok, after measuring and testing and restarting it multiple times I'm still at a loss. After restarting Acorn, Each tool is off by a different measurement, each restart cycle does not produce the same error. We are only talking .005-.012" difference but if I don't re measure and set the offsets, it's off by some amount after it's restarted again compounding the offset error.
Could this be due to cheap home switches? What about interference in wiring? All of my wires are insulated.
I checked and re measured my turns calculation.
Once it's dialed in and running it will reproduce .0002 accuracy according to my DRO. I called it good at .0002 with the Lash Comp.
I've verified this with my DRO and a Mits. .0001 Dial indicator.
Anyone have gremlin bait? How big does my gremlin trap need to be?

Switches is what I was going to suggest as I was reading through this thread.
On a lathe you really need good switches. Proximity switches, hall effect sensors so the machine will home repeatably.
Prove it to yourself. Put an indicator on an axis and test homing repeatability.

On Emcoturns, there is a proximity sensor on the ballscrew pulley. You can rough home to switches and then have the control hunt for the sensor on the ballscrew pulley and then set home. You would have to write a custom Homing Macro similar to this:

M92 /X L1 ;Move to X+ home switch, back off until it clears.
M105 /X P-4 F3 ;Move X minus at 3ipm until input 4 closes
M26 /X ;Set X home here

M92 /Z L1 ;Move to Z+ home switch, back off until it clears.
M105 /Z P-3 F3 ;Move Z minus at 3ipm until input 3 closes
M26 /Z ;Set Z home here


Tell us about your machine, what make and model home sensors you are using and post some pictures of them.

Thanks again Marty, I don't think I'll embarrass myself and post pictures of the limit switches... I was thinking that the tool offsets were based off the #1 tool being set after start up, ALONE. I was thinking the Home switches were just to limit the table from crashing into the spindle or something else. I assumed and you know the rest...
I'll get some proximity switches on the way. Found some close to the ones recommended on the Centroid Site "Gear we use but don't sell"
I'll follow up and also planning on a walk around video with this machine. To me it's really awesome to have a collet closer, bar puller, parts catcher, and gang tool set up that, aside from the tool offsets being messed up, is awesome and very dependable. The simplicity and short learning curve was what sold me in the beginning.
Thanks again

Dbean wrote: ↑Sun Dec 13, 2020 10:08 am Thanks again Marty, I don't think I'll embarrass myself and post pictures of the limit switches... I was thinking that the tool offsets were based off the #1 tool being set after start up, ALONE. I was thinking the Home switches were just to limit the table from crashing into the spindle or something else. I assumed and you know the rest...
I'll get some proximity switches on the way. Found some close to the ones recommended on the Centroid Site "Gear we use but don't sell"
I'll follow up and also planning on a walk around video with this machine. To me it's really awesome to have a collet closer, bar puller, parts catcher, and gang tool set up that, aside from the tool offsets being messed up, is awesome and very dependable. The simplicity and short learning curve was what sold me in the beginning.
Thanks again

You wouldn't embarrass yourself. You would show us what you have and if not optimal we could suggest why and others can learn from it. Keep it to yourself and others having similar issues may not be able to learn.

Visuals are very helpful, good AND not so good!

Good luck!
Marty