Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: plasmacutting on October 31, 2011, 05:02:34 PM
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I am using Mach3 for plasmacutting. How to set X, Y offset for scribe?
Thanks!
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Not really sure what you are asking, can you try and explain a bit clearer?
Hood
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Not really sure what you are asking, can you try and explain a bit clearer?
Hood
I have gantry type plasma machine with one plasma torch and one comp air scribe head. Scribe unit is moving together with plasma torch, but is offset on X and Y axis (compared to plasma torch). When Mach is swiching from plasmacutting to scribe process, G-code says: "start scribe offset - G54", then where Mach should get these offset parameters?
thanks
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There are 254 possible offsets in Mach and you can easily set them up, if just needing 2 you would be best to keep G54 for the scribe and use G55 for the torch or vice versa depending on which is the one used first or most.
How you would set things up is move the scribe to a point and set the axis zero then move so the torch is over the same point and then in MDI type G55 and hit the enter key then you can zero the axis again and that is you just set up the G55 offset.
You can then change back to G54 and you will see how far away the scribe is from where you set zero.
All that then remains is to call the offset from G code when required, ie when scribe make sure you are in the default G54 offset and when you want to use the torch call a G55 from your code to change to that offset.
Hood
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Hood has shown you one way the other would be to use a G92 or G52 offset just before the scribe is used. It will offset the table so the scribe willl be aligned to the work correctly.
Hope that helps, (;-) TP
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There are 254 possible offsets in Mach and you can easily set them up, if just needing 2 you would be best to keep G54 for the scribe and use G55 for the torch or vice versa depending on which is the one used first or most.
How you would set things up is move the scribe to a point and set the axis zero then move so the torch is over the same point and then in MDI type G55 and hit the enter key then you can zero the axis again and that is you just set up the G55 offset.
You can then change back to G54 and you will see how far away the scribe is from where you set zero.
All that then remains is to call the offset from G code when required, ie when scribe make sure you are in the default G54 offset and when you want to use the torch call a G55 from your code to change to that offset.
Hood
Thank you for your help. I am quite new in this and I could not manage. I did exactly as described. When I run G code, sribe makes its shape first, but when it shifts to plasma, it runs far away from the correct position. Please give some notes what should I check or do?
Thank you in advance!
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Does your torch follow the same code as the scribe?
Hood
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Does your torch follow the same code as the scribe?
Hood
G code is following:
%
g00 x0 y0
G54
m08
g01 F700
x50
y50
x0
y0
m09
G55
g00 x0 y0
g01 F700
x50
y50
x0
y0
m30
%
Torch follows the same path but offset is totally different from one I have set.
I have moved torch to the suitable position then set the axis zero. Then I moved scribe to the same positon (ca x36;y-120). Then MDI G54 + enter - X value changes to 812 and Y value changes to -87,42.
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That should work perfectly if you have the G55 offset set correctly.
Easiest way would be if you could touch off something with the scribe head and make sure you are in G54 offset by typing that in MDI and pressing enter then zero the X and Y DROs. You would then type G55 in MDI and hit enter key then touch off the torch to the same thing you previously touched off the scribe at then zero the DROs again.
If that is not working for you then attach your xml and I will have a look. Also attach the fixtures.dat file which is located in the macro folder of the profile you use.
Hood
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Just to make clear, the bit you touch off would need to be where you want the code zero to be.
Alternatively a G52 like Terry mentioned could be used in code instead of fixtures.
Hood
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Just thinking a bit more, do you have home switches?
Hood
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Sorry! I hope that helps!
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OK just had a quick look at the xml and you dont have home switches so you can use that to your advantage.
If you make sure you are in G54 then jog and touch off a point with the scribe, press RefAll then Zero the DROs, next change to G55 and move the torch to the same point then zero the DROs and thats you set. Each time you want to start a new file from a different location just jog to where you want, make sure you are in G54 and then press RefAll and then Zero DROs. That will set the G54 and machine coords zero and your G55 will have already been set by the first time you did that so no need to re set the G55 offset.
Hood
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OK just had a quick look at the xml and you dont have home switches so you can use that to your advantage.
If you make sure you are in G54 then jog and touch off a point with the scribe, press RefAll then Zero the DROs, next change to G55 and move the torch to the same point then zero the DROs and thats you set. Each time you want to start a new file from a different location just jog to where you want, make sure you are in G54 and then press RefAll and then Zero DROs. That will set the G54 and machine coords zero and your G55 will have already been set by the first time you did that so no need to re set the G55 offset.
Hood
Finally I have time to concentrate on my tool offset issue. There is probably something I have missed. I am in G54, choosing the point with the torch, then RefAll and Zero Dros. Then G55 and scribe to the same point, then Zero Dros. If I swich to G54 and press Go To zero, then Torch moves to the correct offset position. If I choose some other location with torch, press RefAll and Zero the Dros, then if I swich to G55 and press Go to Zero then scribe moves to the point I originally set the offset. So G55 offset is not fixed to the G54 location. Where did I go wrong?
Thanks!
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Offsets are fixed to the point your RefAll to or in other words Machine Coordinates or G53. Because you dont have home switches what will happen when you press RefAll is it will zero the Machine Coordinates at the position you press RefAll.
Hood
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Offsets are fixed to the point your RefAll to or in other words Machine Coordinates or G53. Because you dont have home switches what will happen when you press RefAll is it will zero the Machine Coordinates at the position you press RefAll.
Hood
No Ref All will not Zero Machine Coordinates!
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It will and does if you have AutoZero chosen.
Hood
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It will and does if you have AutoZero chosen.
Hood
Yes, now scribe offset works fine - thanks a lot! Would it change a whole offseting concept if I would use home switches?
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If you fit home switches then G52 like Terry mentioned may be your easiest option.
Hood
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If you fit home switches then G52 like Terry mentioned may be your easiest option.
Hood
OK, but is the procedure for setting up offset coordinates for G52 similar to G54/G55?