G76 problem ( i think !! )

[swdiver]

Hi all
Hoping some one may be able to help,
I'm running a small lathe with a cs-labs IP-S controller and Mach 3 turn.
I've only had it running for a few months and until i have learnt to use CAD + CAM software, to make parts i have been generating bits of code with the mach3 turn wizards and then manually editing them to stitch the various operations together.

Below is some code to cut a thread generated with the mach3 simple threading wizard , this runs fine direct from the wizard but if i save it in note pad and then reload it after running another operation it always stops after the first G76 pass at the point where the tool should retract and just hangs there with the lathe spindle still running.

G0 G40 G18 G80 G50 G90 (thread)
G00 G53 X0 Z-183
T707M6
G00 X7.35
G00 Z5
G00 X6.35
M03 S750
M08
G76 X5.1 Z-6.2 Q2 P1.27 J0.006 L45 H0.2 I29 C1 B0.0001 T0
M9
M5

Its probably obvious but what am i missing that makes it work from the wizard but not from my saved file ?

Below is the code i am trying to run before the threading operation , i'm aware this is rough and needs tidying up :unconscious:

G18 G40 G49 G90 G94 G80 ( start)
g0x20
g0z70
s1500
t1010
m3
g0x20
g0z0
g0x10
g01x0 f30
g0z10
G18 G40 G49 G90 G94 G80 (rough)
G0 X11.3 Z1
F90
G0 X8.1
G1 Z-6.24
G0 X10.1 Z-5.3
G0 Z1
G0 X6.9
G1 Z-6.24
G0 X8.9 Z-5.3
G0 Z1
G0 X6.47
G0 Z1
G1 Z-6.24
G1 X11.3
G0 Z1
F90
G0 X6.35
G1 Z-6.3
G1 X11.3
G0 Z1
G18 G40 G49 G90 G94 G80 (end chamf)
M3
G0 X8.3 Z1
F150
G0 X4.6834
G1 X6.7619 Z-0.8
G1 X8.3
G0 Z1
G0 X4.2453
G1 X6.3238 Z-0.8
G1 X8.3
G0 Z1
F100
G1 X3.8453
G1 X6.1547 Z-1
G1 X8.3
G0 Z1
G18 G40 G49 G90 G94 G80 (mid chamf)
G0 X11.5 Z-5.3
F150
G0 X7.8834
G1 X9.9619 Z-7.1
G1 X11.5
G0 Z-5.3
G0 X7.4215
G1 X9.5 Z-7.1
G1 X11.5
G0 Z-5.3
G0 X7.2453
G1 X9.3238 Z-7.1
G1 X11.5
G0 Z-5.3
F50
G1 X6.8453
G1 X9.1547 Z-7.3
G1 X11.5
G0 Z-5.3
s750
G0 G40 G18 G80 G50 G90 (thread)
G00 G53 X0 Z-183
T707M6
G00 X7.35
G00 Z5
G00 X6.35
M03 S750
M08
G76 X5.1 Z-6.2 Q2 P1.27 J0.006 L45 H0.2 I29 C1 B0.0001 T0
M9
M5
M30

[Chaz]

Not sure but isnt it waiting for another cycle start or similar?

[swdiver]

Not sure but isnt it waiting for another cycle start or similar?

But it hasn't finished the G76 cycle , its only made one pass !
The strange thing is it works from the wizard but as soon as i perform another operation it will not work again unless i load it from the wizard again , as if the wizard changes some parameter i'm not aware of or can't see

[m_c]

Does it actually pause, or does it continue to retract very slowly?

There is a 'glitch' with turning, external motion controllers, and certain versions of Mach3, where at the end of the threading move when things should switch from mm/rev to mm/min, it changes mode but doesn't update the feedrate. So if you were doing say a 1mm pitch thread, it'll switch to 1mm/min and retract at that speed until the retract move is done, at which point the feedrate will update to the correct rate.

It's a known problem with later versions of Mach3 that CS-Labs can't do a tapered lead out, and you have to have a groove at the end of the thread. I've also witnessed it when using Mach 3 with my KFlop controlled lathe.

[magicniner]

Try different versions of Mach3, different bugs are present in different versions and the latest is not the best as the inadequate knobsocks who bought the company were balls deep in knackering the product when they stopped trying to fix their cock-ups and moved on to several years of advertising Vapourware and selling broken shit.

[swdiver]

Does it actually pause, or does it continue to retract very slowly?

There is a 'glitch' with turning, external motion controllers, and certain versions of Mach3, where at the end of the threading move when things should switch from mm/rev to mm/min, it changes mode but doesn't update the feedrate. So if you were doing say a 1mm pitch thread, it'll switch to 1mm/min and retract at that speed until the retract move is done, at which point the feedrate will update to the correct rate.

It's a known problem with later versions of Mach3 that CS-Labs can't do a tapered lead out, and you have to have a groove at the end of the thread. I've also witnessed it when using Mach 3 with my KFlop controlled lathe.


Thats brilliant thank you !!
I have just run the code direct from the wizard and from my saved files,
You where correct , it was in fact moving very slowly , i'm not sure how i didn't notice the DRO's changing.
I then ran them while watching the diagnostics screen.
Loading from the wizard automatically sets a G95 mode where as my saved code did not contain the G95 so was still in G94.
I added a G95 to the threading part of my saved code and it ran perfectly.

This has all been a very steep learning curve over the last few months and i must say that the idea of uninstalling and reinstalling another version of mach3 would fill me with dread !!
Can you recommend another Mach3 version that may work,
although I think for now i will just remember to manually add G95 + G94 commands into the code.

I had also spent some time trying to achieve a tapered lead out to a thread with no success so my failure there makes more sense now.

Thank you so much for your help i had been scratching my head for ages trying to figure this out.:courage: