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starting pasma arc after a pause
« on: April 20, 2010, 06:08:52 PM »
So, today I cut out my first project with mach 3  ;D  Being me, I thought I could go right into a larger piece. I lost a good thc and had to pause the program. I then lowered the torch down and attemped to run the program again from the point I hit pause. the torch did not go on. my point is how do I get the torch to start again if I hit pause it this possible?  There are many times I will have to do this in the future. It would be nice to have a simple solution.  any help would be greatly appreciated
Greg
Re: starting pasma arc after a pause
« Reply #1 on: April 20, 2010, 08:35:44 PM »
Greg, are you meaning to start and stop the torch, as with m3,m5? or just if you hit pause because of a misfire and are attempting to ignite the torch again? i find that i need to rewind the file and scroll to the start that was missed and run from here.are you using a touch off macro for the initial starting height?
Re: starting pasma arc after a pause
« Reply #2 on: April 21, 2010, 08:56:28 AM »
I have only cut 2 peices since I got everything together. it uses a touch off at seemingly random points or if it does a long rapid move but not every time it  pierces the metal. The only reason I need to start and stop the torch mid file would be if I have a hang up i need to clear to keep from crashing or for some reason the torch faults and stops cutting (very common with my torch). What I need is some kind of macro or something to tell mach when I hit run after a pause is to do a touch off and restart the torch. is this possible.

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Re: starting pasma arc after a pause
« Reply #3 on: April 21, 2010, 09:59:24 AM »
What I need is some kind of macro or something to tell mach when I hit run after a pause is to do a touch off and restart the torch. is this possible.

 Yes, you coud change the Start button on the screen to a VB button, then the VB in the button would just look at the FeedHold LED and if active do your touch off routine, if not it would do the normal start.
 Hood
Re: starting pasma arc after a pause
« Reply #4 on: April 21, 2010, 01:39:56 PM »
Hood, what you said ???
You guys will have to patient with me as I am very new to mach. I have read the manual several times but it is all still very Greek to me. I have read the MP3000,DTCH and ESP 650 manual from CandCNC also several times (still pretty Greek). There are so many different screens, macros, brains, inputs and outputs and I have no idea how to edit anything as of yet.  Here is the basic function I need/want. When I hit the feed/hold button I want the torch to turn off and hold position. This would allow me to clear any obstructions or reset the torch if it happens to shut off. upon hitting run I would like to torch to do a touch off or at least start the arc and restart the g-code as if nothing has happened. Sometimes I will have to move  back to the start of a line if the torch faulted and restart from the point where I lost the arc. right now I am totally lost and confused. I knew there would be a learning curve to getting this software but I did not know I would need computer engineering and physics degree. I have the utmost respect for you guys that have figured it out and in time i am sure I will but right now I just want to cut things out. It would be helpful if there was Mach for idiots manual.
Recap:
How on earth do I put a stop/restart torch command in the middle of a line after pressing the hold/feed button?
I have no idea what I am doing and I am a complete idiot when it comes to Mach.  ???

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Re: starting pasma arc after a pause
« Reply #5 on: April 21, 2010, 04:13:03 PM »
Afraid I know nothing about plasma so you will have to educate me what you mean when you say Touch Off and Start Arc. Well actually I know what they mean but I am wondering how you do this at the moment. If its a button press or ???????

What I was saying above is you could do similar to what I have done on my machines, I have used Screen4 to change the standard Start buttons into VB buttons and then when opened again in Mach I have put some VB Script into the Start button. What mine do is look at the spindle drive to see if it has been manually disabled (external switch I use when loading the lathes chuck or changing tools on the mill) If the spindle drive is disable and I press Start a message will pop up informing me the drive is disabled and to enable it and press Start again. If the drive however is enabled then the Start button will act as a normal Start button.

So depending on how you do the Touch Off and Arc Start it may be possible to do a similar type of Start, kind of an intelligent Start button rather than just the normal dumb one :)

Hood
Re: starting pasma arc after a pause
« Reply #6 on: April 21, 2010, 05:38:42 PM »
In a touch off the tip of the torch comes down and touches the metal plate. the torch is set up on a floating head on the z axis. as the z comes down and the tip touches the plate the floating part starts to rise and hits a limit switch telling mach the tip has made contact with the material the z then lifts slightly so the tip is just above the plate. Once this is done a signal is sent to mach via the M03 command to turn the torch on. The torch has a 0.4 sec dwell time to ensure penetration then the height of the tip is taken over by the DTCH (digital torch height control) and the line is then cut by G-code coordinates.  The way this is done is all in the post processor for the start of each new section to be cut. There is a button to manually turn the torch on and off though. Is there a way to mate the torch on/off button to a restart button? Like the start from here button that way I could go back to the start of the line in the g-code where I lost arc and continue with the push of the start from here button.  Just a thought.
This is the advice I got from Tom at CandCNC
1. Never hit STOP unless you want to have to re-zero the XY axis. Stop
instantly stops the motion and may dump the contents of the run buffer.
2. Hit FEEDHOLD THEN hit STOP after motion stops
3. Note the G-code line where you stopped.
4. Back up the g-code from the stop line until the previous M03 (torch on). Roll
ONE Line forward after the M03
5. Hit the "NEXT LINE" button (that gets it ready to run from your highlighted
line
6. Lift the Z (jog) if it needs to clear for the move.
7. Jog XY to approx where the pierce point is and do a manual Z home to
reestablish the top of material.
4. Hit the RUN Button and immediately turn off the THC Button in MACH
5. Torch should drop to cut height (off) and movement should start along the
previous cut line.
6. When you get about 1" before the place you need to start cutting click on the
torch. As it hits the new metal click on the THC Button.

With all the capabilities of mach this seems like a lot of steps that could be avoided with a macro or brain or new fangled widgit

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Re: starting pasma arc after a pause
« Reply #7 on: April 21, 2010, 07:54:00 PM »
1 and 2 are definite s, not only for plasma but any machine run by Mach.

Ok so where you say
Quote
do a manual Z home to
reestablish the top of material.
are you meaning you press the Ref Z button?

Hood
Re: starting pasma arc after a pause
« Reply #8 on: April 23, 2010, 11:14:17 AM »
Hood,
 I found a macro that I think will work can you please take a look and tell me what you think. I have been watching the videos on artofcnc but am still pretty new to this whole thing. where would I install these and how would I place the buttons. here is a copy of the email that came with the files.
 

The code assumes that you ref the head using a G28.1 to set the top of the material.

I placed 2 buttons on the screen then assign the code to the buttons. Then I asssigned a hotkey to each button.

To use when running code press the M113 button . Mach will then feedhold then stop and assign all the relative positons to system vars.

NOW you can do what you need to do to the machine.

When ready to return to cutting press the M114 button. The machine will raise to the safeZ height, move to the position where the machine stopped. Next it will ref the head to the top of material, then set Z height. Next it will restart the torch and do a cycle start and resume cutting where you left off.

Please double check it with your  version of mach as some older version may not respond as indicated.

Thanks for all your help.
Greg

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Re: starting pasma arc after a pause
« Reply #9 on: April 23, 2010, 04:26:14 PM »
Looks like they should work :)

Hood