Wrong tool-offset calculation with Emcoturn 120 ( Rear Tool-Turret)

[suntravel]

Hi Michael,

here the video:



I hope you can understand my broken English '

If this issue is fixed, no problem for me to set up my lathe to rear approach and test if tool setup with probe or skim cut works also ok.

I really want that this tool setup on a lathe is working perfectly for all configurations.

And If you want to do me a favor, make G28 work for Y also

Not to speak of second independent spindle and G2/3 in XY plane

[Allin1Chris]

Uwe,

P281 (Tool Touch Off Stylus Diameter) is set to 10.

So when you changed the tool from Front to Rear, you are now touching the "rear side" of the TT and not the "front side", so the diameter of the TT is added to the Reference Location. In addition, where we "expected" you to be was on the "rear side" of the TT but you are on the "front" side, so it has to add the difference between expected reference and where you are at (In this case the diameter again), resulting in the 20 difference you see.

If measuring from Rear or Front facing tool is the same "surface" of the TT, then the Tool TouchOff Stylus Diameter would be 0.

[suntravel]

Sure, but with a manual measure and X Diam set to 0, like you do to set drill holders with an indicator there is nothing to calculate with the stylus diameter. It must be the same regardless of the approach direction. No stylus in use and no X Diam from the Tool Lib to calculate, because both are 0 in this case. If I change P281 it has no influence in this case with front approach, that is ok and must be the same with rear approach.

Uwe

[Allin1Chris]

X-Diam is really just a reference location in 3D space. Just the starting point of where the tool offsets are calculated from (and for tools that would hit the "other side" of the TT have the diameter of the TT factored in).

I suppose we could eliminate the TT calculation entirely for manual measurements and only take the difference between reference position and the current tool position into consideration. The point in which the tool is being measured from must be the same surface regardless of tool vector.

I think this is what your suggesting?

[suntravel]

Hi Chris,

yes that would be a solution, because with manual measurement normally no TT is in use.

It is done with a dial indicator for X Diam =0 or with a skim cut dialing X Diam to the value from the skim cut.

And of course, this way if Skim Cut is 10mm and manual measure rear tooling in a gang tooling setup X Diam had to be set to -10 in this case

So a complete test would be with P161 = 1

Auto Front / Rear
Manual Front / Rear with Dial Indicator / Skim Cut

With the lathe set up with P1=0 and P1=1

Uwe

[suntravel]

I have set up my lathe with the last 5.19 to rear mount

First Set Part X with skim cut
Seconds Set X Diam with the Probe in tool lib
Thrid measure OD T0101 with TTO
Forth measure ID T0202 with TTO

X Diam is 30 with a 10mm TTO
OD T0101 is measured right
ID T0202 is at nearly X50 on the DRO if I drive it physically to ~X10 mm

IMHO Auto Tool Measure with a rear mount configuration is NOK

Uwe

[suntravel]

Here a Video how easy it works perfectly with a front set up lathe, should be same for rear mount, especial if most retrofitted CNC slant bed lathes are rear mount, front mount is mostly on DIY conversions of manual lathes



Uwe

[suntravel]

Since auto measure is supposed to work with an offset TTO also, I made a quick and dirty setup to test this out.

On a front mount configuration, it works perfectly for ID and OD tools.

Uwe

[RTech]

Is there a way to tell the machine the actual location of the TTO probe when it is not on spindle centerline?

Or, do you have to manually jog the tool so it is near the centerline of the probe each time?

[suntravel]

Is there a way to tell the machine the actual location of the TTO probe when it is not on spindle centerline?

Or, do you have to manually jog the tool so it is near the centerline of the probe each time?

No and not necessary, because you always have to jog the tool near the probe in a position ok for auto measure.

With new tools the CNC will not know where the tool tip is.

With an automatic tool arm it is possible on some industrial CNCs to use the probe for auto tool wear measurement, but for new tools you have to jog first.

Uwe