Pierce start before Pierce height reached.

[Ribbedgiraffe]

Hello everyone, Its been a while since I've been on.

I thought I had solved my pierce height problem, but it turns out I had not. After destroying many consumables and being told I needed new software, I parked the machine for a while out of frustration.

Here's the problem. Cut height and pierce height measure out perfectly on cold runs, The second I power up the plasma and try to cut, the problem jumps right out. Mach 3 is starting the pierce while it is in contact with the metal and then raising up to the pierce height after a delay (This is filling my tip with molten steel), where it remains for X amount of time (Thickness dependent). Now, If I understand this properly Mach 3 should not Fire my torch until it is at a predetermined cut height, correct? Would it help if I posted Gcode from the last run?

I'm stumped - I'm still learning - sorry..

[radicalrescue]

ya post the file ill try it on mine an see what i come up with

[Ribbedgiraffe]

N0010 (Filename: 3.16.16 Star Rock Rings or Hummer 12 Bolt Rims.tap)
N0020 (Post processor: Mach3 plasma.scpost)
N0030 (Date: 14/11/2004)
N0040 G20 (Units: Inches)
N0050 G53 G90 G91.1 G40
N0060 F1
N0070 S500
N0080 (Part: Star Rock Rings or Hummer 12 Bolt Rims)
N0090 (Operation: No Offset, 2, T10: Plasma, 0.066 in kerf)
N0100 M06 T10 F45.0 (Plasma, 0.066 in kerf)
N0110 G00 Z1.2500
N0120 X8.2667 Y4.2523
N0130 Z0.1000
N0140 M03
N0150 G04 P0.6
N0160 G01 Z0.0600 F60.0
N0170 G02 X8.3947 Y4.1243 I-0.0000 J-0.1280 F45.0
N0180 G01 Y3.9243
N0190 G03 X10.2664 Y4.3349 I-0.0129 J4.5294
N0200 X11.7941 Y5.4914 I-1.8777 J4.0679
N0210 X12.6973 Y7.1812 I-3.4083 J2.9081
N0220 X12.8101 Y9.0941 I-4.3629 J1.2170
N0230 X12.2515 Y10.6553 I-4.4579 J-0.7145
N0240 X11.1624 Y11.9055 I-3.8609 J-2.2641
N0250 X9.6924 Y12.6727 I-2.7748 J-3.5243
N0260 X8.0440 Y12.8514 I-1.2991 J-4.2909
N0270 X6.4438 Y12.4170 I0.3542 J-4.4694
N0280 X5.1119 Y11.4293 I1.9601 J-4.0346
N0290 X4.2318 Y10.0241 I3.2874 J-3.0373
N0300 X3.9243 Y8.3947 I4.2076 J-1.6377
N0310 X4.2646 Y6.6839 I4.5188 J0.0095
N0320 X5.2336 Y5.2336 I4.1369 J1.7152
N0330 X6.6839 Y4.2646 I3.1655 J3.1679
N0340 X8.4747 Y3.9250 I1.7190 J4.1739
N0350 M05

[Ribbedgiraffe]

Sorry, Its a big one...

[exapprentice]

Hi Ribbedgiraffe

Any chance you can tell us the spec of your table is ie DIY, bought etc also what are you trying to cut and at what settings ie amps speed, make and model of plasma machine, hand torch or machine torch
What method are you using to set the initial cut height ohmic or touch off, have you set your switch offset if required
how is your Z axis set up, have you calibrated the travel of your axis
Do you have THC

Loads of questions and probably more to come but the answers would help people to try and help you

maybe even some pic's of your setup

[acourtjester]

I looked over the G-code and two things come up the pierce height is low (unless you cutting thin metal) 0.100"
The other thing is you do not have a way of finding the metal surface in the Initial start of the cut. If you zero the Z and then move away for that point the metal surface could be to close for a pierce where you start the cut. This also will continue anywhere if Z is not corrected by finding the metal surface at the start of each cut. Having a floating head assembly would help that greatly.
You also said that test runs look fine (as far as the torch height) but when the plasma unit is on the torch fires at the wrong time. Mach will only fire the torch when told to, so if it fires before the M3 command is sent. There is another problem.
short video for what a floating head assembly does no torch fire shown.
https://www.youtube.com/watch?v=irhDCCx9JCg

[Ribbedgiraffe]

Hi Ribbedgiraffe

Any chance you can tell us the spec of your table is ie DIY, bought etc also what are you trying to cut and at what settings ie amps speed, make and model of plasma machine, hand torch or machine torch
What method are you using to set the initial cut height ohmic or touch off, have you set your switch offset if required
how is your Z axis set up, have you calibrated the travel of your axis
Do you have THC

Loads of questions and probably more to come but the answers would help people to try and help you

maybe even some pic's of your setup

Sorry - I suppose details are Important
I'm running a homebuilt 4x8 table with a Gecko 540 controller
Plasma Machine is a Hypertherm Powermax 45 with Machine torch - cutting 1/4" steel Im running 45 amps and only able to cut around 40ipm
Initial cut height is set with touch off, and I have added the offset for the switch in the M3 macro
Z axis is floating
I have a THC but I have not installed it, I need to add a parallel port to the tables dedicated PC.

I purchased the Table running from another gentleman who was only cutting 3/8 steel with it (And demonstrated its function), The only thing I'm doing different than him is running a machine torch vs a hand torch. I assumed this could be causing my pierce issues and changed the M3 macro. Literally his scrap 3/8 cuts look better than my "good" 1/4" cuts.. Beyond frustrating.

[Ribbedgiraffe]

I looked over the G-code and two things come up the pierce height is low (unless you cutting thin metal) 0.100"
The other thing is you do not have a way of finding the metal surface in the Initial start of the cut. If you zero the Z and then move away for that point the metal surface could be to close for a pierce where you start the cut. This also will continue anywhere if Z is not corrected by finding the metal surface at the start of each cut. Having a floating head assembly would help that greatly.
You also said that test runs look fine (as far as the torch height) but when the plasma unit is on the torch fires at the wrong time. Mach will only fire the torch when told to, so if it fires before the M3 command is sent. There is another problem.
short video for what a floating head assembly does no torch fire shown.
https://www.youtube.com/watch?v=irhDCCx9JCg

I do have a floating Z axis, and when I run this G code it does check material height (Now I'm even more confused). I'm glad I took the next couple days off of work to get some time in on this thing.

Here is something I thought was strange. I can not change my Pierce height in sheetcam, I ran over 60 tests and it would not move. I contacted the person whom built it and he directed me to change the M3 macro to get the correct pierce height. Could this be part of the problem?

[BTA Plasma]

There is no G28 in your Z touch off sequence. It will not look for a home switch and there is no switch offset. Your post processor will not generate code for referencing off the top of the plate. Use the MP1000-thc post processor and youll have much better luck.

[Ribbedgiraffe]

There is no G28 in your Z touch off sequence. It will not look for a home switch and there is no switch offset. Your post processor will not generate code for referencing off the top of the plate. Use the MP1000-thc post processor and youll have much better luck.

This may be a really dumb question - but how do I do that?

[sphurley]

SheetCam, top menus, "OPTIONS" then MACHINE then POST PROCESSOR and change your default processor to MP1000THC

[Ribbedgiraffe]

ok - So I've changed it. This actually made it far worse. When loaded into Mach3 under the profile I was taught to use it does not display the part, it has a bunch of circles on top of themselves, as if you were doodling a tornado, not a gusset tab. (Sorry, This is a poor description)
Now - I do not know if this matters, but I use the 540BVFD profile (Maybe this is a made up name) If I switch to the Plasma profile during Mach startup, the part shows properly in the display, but the table goes nuts and tries to jump off the rail.
I'm wondering if I should start over and create a new profile, but I wouldn't even know where to start.

[Ribbedgiraffe]

Here is a quick link to a video I made, just to demonstrate the issue. You can't hear the relay fire the torch, so I say "torch fired" shortly after the relay makes contact.
https://youtu.be/rcNhwK-gaH8

[acourtjester]

Just so you know if you switch profiles it could change the whole setup for the table.
There are XML files that have the setup for the table in the Mach folder if you look in the Mach3/XMLbackup folder you will see files that have the header (540BVD) and then dates after them. The one with the last date is a backup is the one you using. see attached images. Any time you make any changes it generates another current backup XML file.
now if you change profiles you need to rename your current XML file and copy it to the mach folder with the new profile name so all your setting are change for the new profile. Changing profiles can be helpful or do things you don't want.
From the video you attached is looks like there are setting in your 540BVD setup that is causing the problem. Some one may have edited the post processor you are using, some where the software is telling mach to fire the torch before it goes to pierce height.

XML files.jpg (45.34 KiB) Viewed 2119 times

xml files 2.jpg (23.43 KiB) Viewed 2119 times

xml files 3.jpg (27.41 KiB) Viewed 2119 times

[acourtjester]

If you decide to go through setting up your table some of the things you will need to write down would be.
Info from Motor tune, ports and pins under input, (limit switches) outputs, pin for torch fire (output # 1), (motor step and dir pins) under motor outputs.
And also use a generic post processor to start, to get the table functioning basically. The looking for a better post processor to have the floating head option added.
It is not hard just take a little time. You would start by generating a new profile from the mach3 loader and give is a name like "new plasma" and add the info you have written down from the old settings.

[BTA Plasma]

Go to Mach/config/General config and toggle your Distance mode or your IJ mode. I believe your IJ mode is set wrong.

[Ribbedgiraffe]

Go to Mach/config/General config and toggle your Distance mode or your IJ mode. I believe your IJ mode is set wrong.

IJ and distance mode are both set on absolute. Is this wrong?

[Ribbedgiraffe]

If you decide to go through setting up your table some of the things you will need to write down would be.
Info from Motor tune, ports and pins under input, (limit switches) outputs, pin for torch fire (output # 1), (motor step and dir pins) under motor outputs.
And also use a generic post processor to start, to get the table functioning basically. The looking for a better post processor to have the floating head option added.
It is not hard just take a little time. You would start by generating a new profile from the mach3 loader and give is a name like "new plasma" and add the info you have written down from the old settings.

If I create a new one, the old ones will still remain correct?

[Ribbedgiraffe]

ok.. Lets step back to the original problem before I start trying to rewrite the universe.. My head is spinning just from writing down settings.

Now that I've uploaded a video, where would one look to determine what is triggering the torch? is this an issue in the Macro's? Is there a screenshot of something that would help you, help me.

[WyoGreen]

Just looking at your posted g-code, line N0140 fires your torch with the M03 command, line N0160 moves the Z axis to pierce height. So the g-code appears to be the culprit in the torch firing early. It would help you a lot if you learned a little g-code. I seem to remember the manual on Mach3 having a section on g-code that explained things a bit. At any rate, it looks like a change of the Sheetcam post processor is in order. Just remember there may be options in the post processor that will need changed also.

Steve

[Ribbedgiraffe]

Thanks Steve, I need to track down a Mach3 manual, I didn't get one with the machine, and I've been trying to learn everything on various forums.

Correct me if Im wrong here, The M03 command is a Macro correct? Is it possible I goofed something up when changing the M03 Macro?

Here is the M3 Macro

Message( "Setting Torch Height" )
If IsSuchSignal (22) Then
code "G31 Z-3 F20"
While IsMoving()
Wend
code "G92 Z0"
code "G0 Z.25"
code "G92 Z0"
code "G0 Z.215"

End If
code "G4P1"

DoSpinCW()

[acourtjester]

I may be wrong but but mach's list of "M" commands states the M3 is clockwise spindle control but for plasma can be used to send a signal to trigger the torch on. See attached in port and pins under spindle setup M3 can be sent to output #1 and this turns on the torch relay on the table I have worked on.
Not a macro. That is what should happen on line 140 after it had gone to the pierce height of 0.100"
When I run the first 300 line of you g-code that is what happens

[acourtjester]

Here is what is in my post processor for M3 and M5
your post processor may have a macro with a different command to be use M3 differently.

[Ribbedgiraffe]

That is what should happen on line 140 after it had gone to the pierce height of 0.100"
When I run the first 300 line of you g-code that is what happens

m3.jpg

So - When you run the code I generated, it fires the torch at the correct time (Once pierce height is reached)?

The previous owner had me change the M3 macro to raise pierce height, and after changing the M3 macro, it did in fact raise the z axis during pierce. The reason he had me do this was because I could not raise the pierce height in sheetcam any higher, and according to hypertherm spec, I was far too low.

[Ribbedgiraffe]

if G-code is set to fire the torch properly is it possible I've got a wiring issue?
I ran a couple more tests and it appears the torch is being fired at the exact moment the Z axis finds the plate height.