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Get a pierce but no axis move
« on: September 15, 2012, 02:20:14 PM »
On several occasions I get a pierce yet no axis movement. I shut the torch off then it will go to the next axis and resume the code movements.

An example: Today I was running a sign. The first sigh cut perfect. The second started running OK, then after cutting several parts, then it pierced and no axis movement. Part ruined.  I reloaded the code and cut another complete design.

On the next run, it pierced on the 1st cut and held.

I do not know why it does this nor what to do about it. I would like to do something to jog it to start it's movement and resume without ruining the material.

Any suggestions out there.
Only one way to Get-er-Done......Do-er-Right!
Re: Get a pierce but no axis move
« Reply #1 on: September 16, 2012, 12:07:32 AM »
Three things can cause that.  This assumes you are running a THC with Arc OK signal into Mach3.

(1) Consumables need replacing.  A worn electrode will cause poor arc transfer and with THC mode on, mach3 won't move unless it has an arc OK signal.

(2)  You are trying to pierce too far from the plate.

(3) You have too much pierce delay dialed in.  With too much pierce delay, you can blow a hole before the machine moves large enough that you lose arc transfer.

Re: Get a pierce but no axis move
« Reply #2 on: September 16, 2012, 05:57:35 AM »
Thanks for your response.

1. Consumables are new.

2.Pierce is set at .18, per the book. I will try it at .17 then .16 and see if this helps.

3.Pierce delay is set at .01, per the book. I will try .00 to see what this does.

Another inquire in another location brought up the question of my Arc OK light on the THC.  Brought up the question but did not say what to do.

I am learning and need these replys, thanks again.
Only one way to Get-er-Done......Do-er-Right!
Re: Get a pierce but no axis move
« Reply #3 on: September 16, 2012, 09:25:41 AM »
I rarely ever use a pierce delay, although .01 seconds wouldn't have any effect either way. Might as well be 0.  Make sure your pierce height is calibrated.  If you use a G31 or G28 to set pierce height, make sure when you set it at .25 it is actually .25.  

What plasma are you using and what thickness material are you cutting.
Re: Get a pierce but no axis move
« Reply #4 on: September 16, 2012, 11:49:51 AM »
Hey, thanks for the reply. I am way too new at this to know if it is G31 or G28. I am using BobCad and set it using a window for this feature.

Seems like every day it does something new. Yesterday was the pierce and not moving. Today I was cutting and it started perfectly, it was making a long cut, 1/2 way through it the torch went out raised to the rapid ht. completed the run, weht to the next pierce and started up again like normal.

I re-posted the design and it started by raising the torch to go past the stop.  This might be my error, I may have set the Rapid to 5. instead of .5.

I will have to find out what G it is to find out where the error is.

You asked what plasma I am using. I have a Thermal Dynamics  A40, cutting with air and cutting 14 ga. mild steel.

Any help is gratefully accepted.
Only one way to Get-er-Done......Do-er-Right!
Re: Get a pierce but no axis move
« Reply #5 on: September 16, 2012, 06:18:28 PM »
What are you using for a THC?  Did you build the machine.  If not, who did?  Who set up the post in BobCAD for your machine?

Post the first 25 lines or so of a program.  That will tell us how it's referencing.

The A series machines work very well.  We've been using them for 12 years and selling them for 4 years with no issues.
« Last Edit: September 16, 2012, 06:20:28 PM by rrc1962 »
Re: Get a pierce but no axis move
« Reply #6 on: September 16, 2012, 06:26:52 PM »
The THC is by Texas Micro Circuits and the machine was built by ProCut.  BobCad set up the post. Here is several lines of a program

(BEAR HEAD WELCOME.NC)
(Post processor: Plasma THC300.millpst)
(FRI. 09/07/2012)
G20 (Units:Inches )
G53 G90 G40
G0 Z0.1
X1.1516 Y-0.0901
(FEATURE PROFILE)
M06 T1
G00 Z0.5
G28.1 Z0.12
G92 Z0.0
G00 Z0.1014
G92 Z0.0
G00 Z.375
G00 Z0.25
M03
G04 P0.2
G2 X0.3847 Y0.4812 I0.0954 J0.9286
G2 X0.3657 Y0.577 I0.231 J0.0957
G1 X0.3728 Y13.6265
G2 X0.3801 Y13.6861 I0.25 J-0.0001
G2 X1.0622 Y14.2134 I0.6729 J-0.1656
G1 X1.6956 Y14.2111
X1.3067 Y15.9669
X2.3775
X2.3953
X3.288
X3.3034
X4.2753
X4.3761
X6.2185
Y15.0904
X6.1558
Y14.5865
X6.2185
Y14.21
X6.2274
Y15.9669
X7.2922
Y14.6492
X7.9874
G2 X7.9772 Y14.8389 I1.2912 J0.1646
G2 X8.2082 Y15.5928 I1.1682 J0.0545
G2 X8.2153 Y15.6019 I0.2004 J-0.1495
G2 X8.622 Y15.8897 I0.7286 J-0.5982
G2 X9.0803 Y15.967 I0.4396 J-1.2099
G2 X9.6647 Y15.8351 I0.0442 J-1.1651
G2 X9.6826 Y15.8248 I-0.1158 J-0.2216
G2 X10.0993 Y15.2664 I-0.5222 J-0.8243
G2 X10.1086 Y15.1881 I-0.2405 J-0.0681
G2 X10.3085 Y15.5897 I1.1146 J-0.3045
G2 X10.3143 Y15.5969 I0.1979 J-0.1528
G2 X10.7308 Y15.8893 I0.7488 J-0.6237
G2 X11.1901 Y15.967 I0.4424 J-1.22
G2 X11.9501 Y15.7315 I0.0546 J-1.1678
G2 X11.9589 Y15.7245 I-0.1508 J-0.1994
G2 X12.2485 Y15.313 I-0.6133 J-0.7393
G2 X12.3258 Y14.8506 I-1.2138 J-0.4406
G2 X12.2782 Y14.4567 I-1.499 J-0.0184
G2 X12.1974 Y14.2468 I-0.9562 J0.2473
G2 X12.1773 Y14.2096 I-1.0506 J0.5455
G1 X12.3626 Y14.2098
Y15.9669
X13.5253
X13.5848 Y15.7198
X13.6436 Y15.9669
X14.8077
Y14.21

Only one way to Get-er-Done......Do-er-Right!
Re: Get a pierce but no axis move
« Reply #7 on: September 16, 2012, 06:31:38 PM »
Where can I get info on reading a g-code.  I am quite new and would like to understand more.  I sure over the years I will pick it up so I would like to start. 

This will also help me understand some of the language used in the forums.
Only one way to Get-er-Done......Do-er-Right!
Re: Get a pierce but no axis move
« Reply #8 on: September 17, 2012, 12:08:53 AM »
This is a good reference....

http://en.wikipedia.org/wiki/G-code

You're using G28 to reference.  I've always used G31.  Never had much luck with G28.
Re: Get a pierce but no axis move
« Reply #9 on: September 17, 2012, 04:19:45 PM »
I looked this up. I can see the parallel between what my codes look like.

You mention my using G28 instead of G31. This is set in BobCad, nothing I do.  What would happen if I went and edited all the G28 and changed to G31?  What did you find that G28 did and what was the change with G31?

This forum post started  with my getting a pierce and no axis movements.  Let me tell you of today:

I ran a design 7 times with a little dross and some angular from the right side of the torch.

I loaded another design and it would not move after the pierce.  I reloaded the first design and got the same reaction.  I am dumbfounded.

The only difference between the post above is the GOO Z0.16 instead of GOO Z0.25 above.

When I shut off the torch I measure the torch ht. as 1/8".

Id get one person suggesting I ground my table and I did this between the successful runs and the 2nd design.

Well thanks for hearing me out.....Any thoughts you might have are greatly accepted.
Only one way to Get-er-Done......Do-er-Right!