Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: peterm on April 18, 2020, 10:37:48 AM

Title: Machine goes to Z zero at start of a program
Post by: peterm on April 18, 2020, 10:37:48 AM
Quick question guys. Just went to help a friend with his machine running Mach3. We cut a piece of acrilyc in a jig and when we started the cut the machine went to zero on the Z putting a whole right through the part. This happened every time.
The cuts after i jogged the machine to a location away from the part before starting. It zeroed on the Z but at least didn't damage the part. Later on the machine would do the same thing now instead of the z going to zero it would go about .5" below zero.
Any input would be greatly appreciated.
Title: Re: Machine goes to Z zero at start of a program
Post by: ZASto on April 18, 2020, 10:50:34 AM
Can you share first 10 to 15 lines of G-code of the program?
Title: Re: Machine goes to Z zero at start of a program
Post by: peterm on April 18, 2020, 11:07:34 AM
Absolutely! Thanks!

N140 ( MATERIAL - ACRYLIC )
N150 G20 G81
N160 G0 G17 G40 G49 G90  Z1
N170 (  1/8 FLAT ENDMILL  TOOL - 232  DIA. OFF. - 232  LEN. - 232  DIA - 0.125 )
N180 T232 M6
N190 A-0.
N200 G0 G90 S6000 M3  X.5 Y7.
N210 H232 Z.25 M8
N220 X.7867 Y.8091
N230 Z.2
N240 G1 Z-.14 F40.
N250 G2 X21.25 Y7. I21.9633 J-35.6822 F80.
N260 G1 Z.06 F50.
N270 G0 Z.11
N280 X21.5 Z.25
N290 X21.25 Y6.
N300 Z.2
N310 G1 Z-.14 F40.
N320 G3 X1.9509 Y.5 I1.5 J-41.8731 F80.
N330 G1 Z.06 F50.
Title: Re: Machine goes to Z zero at start of a program
Post by: ZASto on April 18, 2020, 11:22:43 AM
Might be something with your tool change macro (M6) called in line N180?
Title: Re: Machine goes to Z zero at start of a program
Post by: peterm on April 18, 2020, 11:32:48 AM
Might be something with your tool change macro (M6) called in line N180?
I doubt is that. It plunges before reaching that line...
Title: Re: Machine goes to Z zero at start of a program
Post by: ZASto on April 18, 2020, 11:44:56 AM
Well, Mach can not, on its own, do the things that are not in G-code program or macro or initialization string (in General Config).

But, closer look at your G-Code gives a possible error: N150 G20 G81

G81 stands for Canned Cycle - Drilling
Title: Re: Machine goes to Z zero at start of a program
Post by: peterm on April 18, 2020, 04:15:59 PM
Well, Mach can not, on its own, do the things that are not in G-code program or macro or initialization string (in General Config).

But, closer look at your G-Code gives a possible error: N150 G20 G81

G81 stands for Canned Cycle - Drilling


Thanks, not sure why G81 is there. I'll give it a try without it.