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G76 incorrect feed and rapid rates
« on: September 15, 2014, 08:03:16 PM »
When running the program that I've created using the Simple Threading Wizard.  The program created by the wizard using the G76 threading cycle creates bad threads.  The first pass feeds and returns at the pitch feed rate.  All subsequent passes the tool cuts at a higher feed rate and the returns to the start at the programmed pitch feed rate.    When I run the wizard creating a program using the G32 threading cycle with the same settings as the G76. The threads are good.  I've checked my config settings numerous times and sent the G76 program to someone to run.  They had no problem making the threads with my G76 program.  I'm running Mach3 version R3.043.066 on a Dell Optiplex 745 1.86GHz with 1.99 GB of ram operating system WinXP service pack 2.  

Does anyone know why the G76 cycle feeds and rapid rates would be reversed and the G32 cycle would be correct?  Both are using the M1076.M1S macro to create the moves.  

Re: G76 incorrect feed and rapid rates
« Reply #1 on: September 16, 2014, 02:47:46 PM »
hi
i think your problem is you are using 066 version this is not very good for thread cutting , use version 057 to 062 these are good for threading & are available on this site somewhere
i have found it easier to hand code threads rather than use the wizards
this is the code i use to produce a m12 x 1mm pitch internal thread
G0 G40 G18 G80 G50 G90 G95
M6 T1616
G0 X10.80 Z15.00
M3 S550
G76 X12.00 Z-11.50 Q1 P1.00 J0.080 L45 H0.250 I29 C0.250
hope this is of some help to you
all the best
robert
« Last Edit: September 16, 2014, 02:49:40 PM by ministeam »
Re: G76 incorrect feed and rapid rates
« Reply #2 on: November 19, 2014, 12:37:13 PM »
Did you ever get this problem fixed? I am having the same results. I've tried everything I can think of, including uninstalling the latest version, and re-installing .057.Any help is greatly appreciated. 
Re: G76 incorrect feed and rapid rates
« Reply #3 on: May 01, 2017, 12:21:48 AM »
Looking for solutions to this exact same problem.  Second cut pass and on till the end of cycle, feed and retract speeds are reversed.  My pitch was set to .040, and my 1st pass feed was .040 ipr, then the second pass feed was .065 ipr and the retract feed was .040 ipr. and so on till the end of the cycle.

I have read quite a few people with the same issue, but haven't come across any solid solutions yet, except to try earlier versions of the software, which most have tried with no resolve.

Anyway, if anyone reads this, and may know of a cause/cure, please let me know!  I'd love to get this friggin thing finally cutting threads after 4 years of owning it!! lol

Thanks!

Brian

Offline RICH

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Re: G76 incorrect feed and rapid rates
« Reply #4 on: May 01, 2017, 07:49:43 AM »
A write up called Threading On The Lathe Mach3 can be found in member's doc's.

I use version  062 and have the code output  set for G32. Don't use the G76 much and worked when tested.
The advantage of G32 output is that one can monitor the passes.

Since Mach3 is what it is and won't be updated just use what works.

RICH
Re: G76 incorrect feed and rapid rates
« Reply #5 on: May 01, 2017, 10:06:38 AM »
My old computer worked fine for a while, but then started doing this. I tried uninstalling and re-installing differant versions, but it didn't help. Unfortuneatly, my only way I could resolve this was to change compuer brands. Now, every thing works as it should again.