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Author Topic: G76 threading problem  (Read 2493 times)

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Offline Rimmel

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G76 threading problem
« on: March 11, 2014, 03:33:33 PM »
Got a problem with G76

Quote
G0 G90 Z5 X9.84
G76 X8.95 Z-21 Q2 P0.75 J0.03 L45 H0.05 I29 C0.3 B0.01 T0
G80

This code works 90% of the time but then will suddenly stick on 0.75 feed, whereas when it runs properly it goes to 0.75 feed when at the point of starting the thread and then changes to 600 feed when cutting the thread.

thanks
Rim

Offline DaBase

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Re: G76 threading problem
« Reply #1 on: January 04, 2017, 06:44:27 AM »
G76 did not worked because of rapid infeed at crazy rates, for example, in metric threads at 1000RPM and pitch 1.5mm machine started operating at F1.5/rev ignoring Mach3 Motor Tuning settings and tried to do rapid feed on X axis in very small distances at 1500mm/min momentary which causes missing steps for steppers and PID error for Servo systems. We have found that on Mach3 Turn G76 doesn't work well ignoring acceleration settings comparing to G32.
On our new screenset, we have fixed this issue by using G32.

http://www.machsupport.com/forum/index.php/topic,33852.msg234743.html#msg234743
We <3 to Code();

Offline RICH

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Re: G76 threading problem
« Reply #2 on: January 04, 2017, 07:26:35 AM »
Have not used  G76 for threading in a long time, but back in time it worked fine for me.
Could it be Mach version related?

BTW,
Preference here is to have  the threading macro set for G32 code generation since  it has never given me a problem.

RICH

Offline Rimmel

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Re: G76 threading problem
« Reply #3 on: January 04, 2017, 07:32:41 AM »
Preference here is to have  the threading macro set for G32 code generation since  it has never given me a problem.

RICH

How do you set that it to G32?

thanks

Offline RICH

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Re: G76 threading problem
« Reply #4 on: January 04, 2017, 07:06:57 PM »
Rimmel,
See page 47 in my write up called "Threading On The Lathe - Mach3 Turn".
Should be in Members Docs.

RICH
Re: G76 threading problem
« Reply #5 on: May 31, 2018, 10:45:27 PM »
Wow, I thought I was going crazy with G76.

Thanks for the info