Yo HELP with the plasma cutter (brady!) or ANYONE!

[james6789]

ok, first. every time we go to cut something, it wants to do the different parts twice, and when you look at the page with all the numbers and stuff, all the movements are listed twice so i have to delete the stuff that shouldnt be there.
2nd-most of the time when i go to cut the plasma tip comes down, touches(like its supposed to) comes back up about 1/4-1/2", then the plasma starts going down, but right before the plasma actually strikes the metal, it goes dead. it can take 5 times to make it actually strike, and its not very productive on a big project when it has to stop and start 20 times. HELP OUT!

[john_david]

Cant help with the Start Stop issue but did you check to make sure you dont have 2 copies of the vectors on top of each other for the cutting twice issue ?

JD

[james6789]

well i make what i want to cut, say a square, then i make the toolpaths for it, save the tool paths for it, then go to cut and its there twice

[Brady Watson]

Thomas,
It is cutting twice because the stepdown you have listed for the tool is smaller than the thickness of the material. While this is valid for cutting wood, you need to enter a material thickness of .001 on the startup screen when using plasma. I cover this on my PW Video ~ www.cncvideos.com (http://www.cncvideos.com)

In regards to Q2, take the torch apart and make absolutely certain that it is surgically clean. Even a little miniscule glob will ground/short the torch and keep it from firing properly. Check all wiring and listen for the control box to kick on the relay (output 2 I believe) to click on when the torch is supposed to fire.

I am on the road training at the moment, but will check in here Fri night to see how you are doing.

-Sparky

[james6789]

ok, ill do that, thanks, one more thing, it just seems like the torch comes up too much before it turns on. and from what i hear from my teacher youre the guy that came to vegas to put our shopbot together last summer, at Votech high school. ill post up tomorrow to let you know how its doing, Thanks

Thomas

[james6789]

first problem is fixed no more doubles, thanks, but i cleaned and recleaned and recleaned the torch and its still not firing everytime, it can take 5 trys to make it want to fire. i think it comes too high off the plate before it turns on, how high (if any) should it come up? thanks again,

Thomas

[Brady Watson]

Thomas,
Tell Mr. Boyer I said hello!

Take a look at this file generated in PW2:

'SHOPBOT PLASMA TORCH PART FILE
'GENERATED BY PART WIZARD
' UNITS = INCHES
'----------------------------------------------------------------
&PDelay = .5 'Pierce delay - Set by torch charts, use tenths or full seconds
&ZBOT = .25 'Set to ideal pierce height - adjust for thickness and amperage
SA 'Set to absolute coordinate mode
SW,0 'Cut off the warning (necessary for proper dwelling time)
'VD,,,0 'Set ShopBot to inch mode
SO,1,0 'Make sure that torch is off before beginning
'----------------------------------------------------------------
MS,1.6
JZ,1.000000
J2,0.000000,0.000000
J3,4.182900,3.489600,1.000000
C4, 'Torch On
M2,4.557900,3.489600
CG, ,4.597900,3.449600,0.040000,0.000000,,-1
M2,21.604700,3.449600
CG, ,21.644700,3.489600,-0.000000,0.040000,,-1
M2,21.644700,13.331400
CG, ,21.604700,13.371400,-0.040000,-0.000000,,-1
M2,4.597900,13.371400
CG, ,4.557900,13.331400,-0.000000,-0.040000,,-1
M2,4.557900,3.489600
C5, 'Torch Off
J3,0.000000,0.000000,1.000000
JZ,1.000000
J2,0.000000,0.000000
'----------------------------------------------------------------


The &ZBot variable value (in this case .25") is the height at which the torch fires. If it is too high, it will not fire the torch because it is not completing the circuit (gap too big, just like a spark plug), so check that value and make sure that it isn't too high. .25" is a pretty good value to begin with, but you may want to try a smaller value to see if it fixes the problem if it is already @ .25". Not to state the obvious, but make sure that the HT ground clamp is as close as you can safely get it to the workpiece.

Be sure to read thru the Hypertherm manual for recommended settings for the material you are cutting. Depending on material thickness, the ideal pierce height will change in order to prevent back splashing liquid metal into the torch. So if you are cutting 1/2" the pierce height should be higher than if you are cutting 1/16" thick material. The Hypertherm manual has these values in it, so .25" is not the ideal height for every material.

Once you get the right settings for a given material WRITE THEM DOWN!!! AND edit the settings in PartWizard for that material so that you don't have to spend time finding the ideal settings down the road.

If this does not help, call ShopBot and talk to Chris. He is very good at troubleshooting plasma issues.

Hope that helps!
-Brady

[james6789]

ok, thanks a lot, youve been a really big help. Thanks again

Thomas