Manual tool change problem

I’m just using the touch off option.

I cannot save my tool lengths because the spindle is similar to a router collet setup. So it’s impossible to get repeatable tool lengths.

There are ways of getting tool length compensation going in Axis following a manual tool change, but it is a little fiddly.

The way I've done it is to add a touchplate to my mill and remap the M6 command into a subroutine to make Axis measure the length of each tool every time a tool change is performed. Method is outlined here:

forum.linuxcnc.org/forum/10-advanced-con...h-off?start=30#48235

This works even if your collet/tools isn't designed to use preset-height cutters. It just measures the length of each tool and adds or subtracts that offset from the initial touch off.

stidrvr wrote: I’m just using the touch off option.

I cannot save my tool lengths because the spindle is similar to a router collet setup. So it’s impossible to get repeatable tool lengths.

Then you don't need to use TnM6 at all.

Here's what I do in that case.
After putting the tool in I jog down until I'm close to the top of the material and using a dowel I slowly move up until the dowel just clears under the tool.Then press the "Touch Off" button and enter the diameter of the dowel and your done with Z

Another "trick" I use to set the X0 of the material is to have a dowel in the spindle and with the material loose in the vise I jog up to the side and press the material against the dowel and tighten the vise. Now I Touch off the X axis (make sure X is selected) and enter 1/2 the dowel diameter. If the left side is X0 then do the above on the left side and enter -1/2 the diameter of the dowel.

The rear face of the vise is always my Y0 but that could change depending on the setup.

JT

BigJohnT wrote:

stidrvr wrote: I’m just using the touch off option.

I cannot save my tool lengths because the spindle is similar to a router collet setup. So it’s impossible to get repeatable tool lengths.

Then you don't need to use TnM6 at all.

Here's what I do in that case.
After putting the tool in I jog down until I'm close to the top of the material and using a dowel I slowly move up until the dowel just clears under the tool.Then press the "Touch Off" button and enter the diameter of the dowel and your done with Z

Another "trick" I use to set the X0 of the material is to have a dowel in the spindle and with the material loose in the vise I jog up to the side and press the material against the dowel and tighten the vise. Now I Touch off the X axis (make sure X is selected) and enter 1/2 the dowel diameter. If the left side is X0 then do the above on the left side and enter -1/2 the diameter of the dowel.

The rear face of the vise is always my Y0 but that could change depending on the setup.

JT

I actually have a simple touch off plate using the Z home switch input and a .25" piece of aluminum. I found a video showing how to setup a button in AXIS to auto touch off the Z from the work piece then deducting the thickness of the aluminum plate.

curtisa wrote: There are ways of getting tool length compensation going in Axis following a manual tool change, but it is a little fiddly.

The way I've done it is to add a touchplate to my mill and remap the M6 command into a subroutine to make Axis measure the length of each tool every time a tool change is performed. Method is outlined here:

forum.linuxcnc.org/forum/10-advanced-con...h-off?start=30#48235

This works even if your collet/tools isn't designed to use preset-height cutters. It just measures the length of each tool and adds or subtracts that offset from the initial touch off.

This is exactly what I have been looking for. Im currently setting up my jobs in fusion using multiple setup, therefor running a separate program for each tool change. I'll look over the thread to see If I can implement using my touch plate. Thank You!

Hello - thanks for all the replies.

I assume that the Z-axis DRO on the screen display is the actual tool tip position
If that is so, all intermediate positions of the display appear to be OK
impossible to measure or check as the tool keeps moving even with single step mode in operation
The first tool change always seems to occur at whatever level Z is set to at the start of the run
I can get around this by issuing a dummy tool change at the start of the program with the TLO set at around 2

Is it possible to set the AXIS GUI in some sort of pause mode during a run that will enable manual control (either by jogging or issuing MDI commands) and possibly using the touch-off command
I can only get it to do it by effectively killing the run - that leaves me with the problem of restarting it at the correct line - not good.

There is a definite bug in the M6 routines when different tool lengths are involved -
clicking on the tool change continue button instantly moves the display to the new tool position, but omits to move the actual mill Z-axis - the clue is in the "instantly".
It would be good to fix this, but where is the source code? I have found a load of code in github.com/LinuxCNC/linuxcnc/tree/master/docs/src/code but which is the relevant bit?
If I fix my own version, do I need to compile it? If so, how? Or do I just remap the M6?

The manual says about remapping the M6 code - "Note than when remapping an existing code, we completely disable this codes’ built in functionality of the interpreter".
Obviously if I am going to remap the M6 it would be good to see what the original version is doing so I can replicate it - another good reason to find the source code

Once that is fixed, I think there is a need for a new M6 that copes with different tool lengths.
If the headstock is moved to the new tool length (which is the case if the above bug were fixed) there is a risk of crashing the previous tool into the material (or other parts of the mill) if the new tool is shorter.

Tool change should be a 2 step operation where different tool lengths are involved -
first - move to the TLO position for current tool - remove tool
second - move to the TLO position for the new tool - fit new tool, save tool data for next tool change first stage

Parameters for the above operations appear to be -
#5400 - tool number
#5403 - Z tool offset
#5422 (also called #<_z>) - current Z position


My drills vary in length from 1.5" to 4.25", the drill chuck adapter adds a further 1.8" to that
I am doing a lot of drilling operations in the mill, hence the problem with the tool lengths

Jog & MDI appear to be inactive during M6 - this is explicitly stated for M0 & M1, but not mentioned for M6
So how do you jog (or do an MDI) in the middle of a program execution?