I’ve had an issue with my cut failing during the first step, multiple times over the last year. Yesterday, however, I noticed if I ran a program, the machine would move to the first cut location, fire for about 5-6 seconds and then stop. After a few times of trying to get it run with changes in the pierce cut times, pierce height, and even changing all consumables, without any luck, I paused the operation and then resumed it. When the cutter moved to the next location, it fired, made the pierce and then ran the rest of the program without any issues. I tried to run the program again on the same material and had the same result of not cutting the first feature. I put a new piece of material on the machine, ran the program and had the exact same result. The cut failed on the first feature but after pausing and resuming, the rest of the features cut perfectly. Does anyone have any idea why the cut fails on the first feature only?
What plasma cutter are you using?
Can you open your g-code file with notepad and copy and paste the first 20 lines here?
How many times does this particular program require the torch to be turned off, travel to a new spot and then begin cutting again? Is there just the first and second contour or are there more in this one program?
What is that first feature? Is is a single line, small circle, tiny detail?
Sure enough, this happened again today on a completely different part. Here are the first lines of the G-code (from sheetcam)
(v1.6-sc)
G90 G94
G17
G20 (Units: Inches)
H0
G0 X1.564 Y0.7394
G92 Z0.
G38.2 Z-5.0 F100.0
G38.4 Z0.5 F20.0
G92 Z0.0
G0 Z0.02 (IHS Backlash)
G92 Z0.0
G0 Z0.15 (Pierce Height)
M3
G4 P2.75
G1 Z0.06 F5.0 (Cut Height)
H1
G2 X1.5534 Y0.735 I-0.0106 J0.0106 F80.0
G2 X1.5384 Y0.75 I0.0 J0.015
G2 X1.5428 Y0.7606 I0.015 J0.0
H0
M5
G4 P0.5
G0 Z2.0
G0 X1.7792 Y0.7076
That is an extremely long pierce delay!
That was an attempt to keep the torch from cutting out.
More likely to cause it to cut out. If it pierces too long it will run out of metal to cut and stop.
Pierce delay should be around 0.150 seconds.
Feed rate on plunges looks slow also.
I was going to suggest this but I wasn’t sure I was reading it right. Looks like it’s set for 5 ipm?
That is how I took it as well. I run mine at 100 IPM.
That looks like you are using the Thermal Dynamics modification of the Firecontrol post processor in Sheetcam. That is the only Firecontrol Post Processor that has a 2" retract height. It is named “Fireecontrol v1.6 TD mod retract”. Don’t use that unless you are using a Thermal Dynamics plasma cutter that requires an extra 1.5 seconds of delay on the first pierce.
As noted above, change your plunge rate to at least 50 IPM.
The super long pierce delay and the slow plunge rate will both have the effect of the torch running out of metal to cut and shutting off before it can move.
Thank you all for the suggestions, I will adjust the settings and report back.
The thing is, it never makes it through the metal, it burns the top for a few seconds and then just cuts out.
You are correct, it was on the TD mod retract, good catch!!
Your plasma will not pierce the material?
Have you tried to cut by hand? Your issue may be your plasma cutter.
Yes, but it is very sporadic and usually on the very first pierce. If I skip the first feature, it pierces and cuts all of the rest of the part without any issues.
Got ya I remember you saying that now. It could be the slow plunge rate. I was just curious. I do remember you saying it works after the first.
Try using the standard Firecontrol v1.6 post processor and that should fix your first pierce issues. That TD mod retract PP adds 1.5 seconds to the first pierce to bypass a safety feature on the Thermal Dynamics machines.
Wow…Déjà vu
Ok, I changed the post processor, pierce delay and plunge rate. Now the Plasma will not fire at all when I run the program. (I am using the Razorweld 45 plasma)
I manually fired the plasma and it works fine, it is something in g-code.
Here is what I’m using now:
(v1.6-sc)
G90 G94
G17
G20 (Units: Inches)
H0
G0 X1.564 Y0.7394
G92 Z0.
G38.2 Z-5.0 F100.0
G38.4 Z0.5 F20.0
G92 Z0.0
G0 Z0.02 (IHS Backlash)
G92 Z0.0
G0 Z0.15 (Pierce Height)
M3
G4 P0.15
G1 Z0.06 F50.0 (Cut Height)
H1
G2 X1.5534 Y0.735 I-0.0106 J0.0106 F80.0
G2 X1.5384 Y0.75 I0.0 J0.015
G2 X1.5534 Y0.765 I0.015 J0.0
G2 X1.5684 Y0.75 I0.0 J-0.015
G2 X1.564 Y0.7394 I-0.015 J0.0
G2 X1.5534 Y0.735 I-0.0106 J0.0106
G2 X1.5384 Y0.75 I0.0 J0.015
G2 X1.5428 Y0.7606 I0.015 J0.0
H0
M5
G4 P0.5
G0 Z1.0
G0 X1.7826 Y0.7251