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View Full Version : what should i know about plasma cutters?



canadian_driver
10-29-2006, 04:32 PM
i have an opertunity to buy one cheap, i think, its a pak-master-25. is this a good one i have no idea what these go for normally, this one is being sold for $500 the guy says it can cut up to 1/4 inch plate

rsl
10-29-2006, 08:38 PM
No idea about the Pakmaster plasma but I have run a 200 amp Hypertherm/Koike plasma & oxy acetylene combo cutting table for the last 6 years.
Important things about plasma cutters is:

1.Clean dry air - the drier the better & cleaner the better.

2.NEVER fire it when it is not in contact with the plate-this is very hard on nozzles and electrodes as the arc attachs itself to the nearest metal, if it is the nozzle and not the plate you are cutting it will wear the electrode and nozzle prematurely.

3.Always attach the ground to the material being cut or as in #2 it will prematurely wear the consumables-ie nozzle and electrode.

4.Don't run more power than you have to for a given thickness.

5.Maintain an even cutting speed that is correct for whatever thickness you are cutting.

6.Always finish your cut with the tip still contacting the plate so #2 doesn't happen.

AprilzWarrior
10-29-2006, 09:10 PM
No idea about the Pakmaster plasma but I have run a 200 amp Hypertherm/Koike plasma & oxy acetylene combo cutting table for the last 6 years.
Important things about plasma cutters is:

1.Clean dry air - the drier the better & cleaner the better.

2.NEVER fire it when it is not in contact with the plate-this is very hard on nozzles and electrodes as the arc attachs itself to the nearest metal, if it is the nozzle and not the plate you are cutting it will wear the electrode and nozzle prematurely.

3.Always attach the ground to the material being cut or as in #2 it will prematurely wear the consumables-ie nozzle and electrode.

4.Don't run more power than you have to for a given thickness.

5.Maintain an even cutting speed that is correct for whatever thickness you are cutting.

6.Always finish your cut with the tip still contacting the plate so #2 doesn't happen.

Well said.

chopshop
10-30-2006, 12:45 AM
#2 and #6 - some newer plasma's have a pilot arc that doesn't eat up nozzles when powered up, but not touching metal. still not good for them, but not so bad.

i have a hypertherm 380 that has this feature.

"#6 Always finish your cut with the tip still contacting the plate so #2 doesn't happen"

my plasma needs a 1/16-1/8" standoff, the tip never touches the work. the tip will stick to the metal if it touches.

rsl
10-30-2006, 08:35 AM
#2 and #6 - some newer plasma's have a pilot arc that doesn't eat up nozzles when powered up, but not touching metal. still not good for them, but not so bad.

i have a hypertherm 380 that has this feature.

"#6 Always finish your cut with the tip still contacting the plate so #2 doesn't happen"

my plasma needs a 1/16-1/8" standoff, the tip never touches the work. the tip will stick to the metal if it touches.

A lot of the hand held plasmas have a porcelain cup on the end to maintain the standoff amount, but you are correct that the tip shouldn't contact the plate.
The 200 amp hypertherm has the pilot arc feature also but it is still very hard on consumables when they fire when away from the plate(the auto height control screws up now and then on this one) or if you run off the sheet under full power.
The hypertherms ramp up the power as you start the cut and down again as you finish the cut so it is best to have the plate within arc distance at both times as the arc will attach itself to whichever is closest, either plate or consumables.