Hi everyone,
I've recently purchased a new PM 85 with machine torch to replace on older TD unit on my table. I ran a few cuts on 1/4" A36 and was quite impressed with the cut quality. Then I had a small part in 3/4" A36 to cut and thought that I may as well try this machine on that instead of cutting with oxy/fuel. I drew up my trusty test block in sheetcam and tried it out.The first 2x3 inch rectangle with two 3/4" holes was also quite encouraging even though I cut the holes at 24 ipm feedrate. I went ahead and cut the actual part and this is when the trouble started. The part ended up with about 7 degrees of bevel that gave the part a parallelogram shape from the end. I could actually see the arc being deflected towards one side of the table.
For the 3/4 I used genuine 85A consumables with all numbers on the parts matching the owner's manual numbers for the consumables. Pierce height .24", cut height .060". and 24 IPM. I never even bothered with THC on these small test parts since they are only a few inches long.
I assumed that I picked up a bit of piercing slag on the nozzle and changed it. Still have arc deflection. I decided to try 3/8" A36 with the 65A nozzle and book settings. Still have parallelogram problem. Tried 1/2" at both 65 and 85 amps with appropriate consumables and it still does it.
To make a long story somewhat shorter, this machine refuses to send an arc straight down through the plate. It's always pointing off in the same direction (usually towards the back of the table but it varies somewhat).
It does this at 45, 65 and 85 amp settings. At each power level I am using the proper mechanized shielded consumables although only the nozzle differs from one amperage level to the next. I have replaced everything including nozzle, electrode, retainer, swirl ring, and shield cap multiple times. Inspection of nozzles at 30x magnification reveals no reason for this behavior.
Pierce height and cut height are bang on verified by feeler gauge. When THC is on height is perfect as well, usually only 2 or 3 volts off of book specs. I have been using book specs for best quality through all this testing. Pierce delay is also by the book and is adequate to complete the pierce.
Air pressure never drops below 100 at machine inlet while cutting or doing a test flow from service screen even for several minutes. 1/2" ID line from compressor to coalescing filter and then a large desiccant dryer.
70 amp breaker and then 65 feet of #6 copper feeding this machine. Volts at 240 to 245 when idle and drop to 220 to 225 on service screen when cutting at 85 Amps.
Work cable is bolted directly to slat frame. Additional #2 cable and clamp from this point directly to workpiece. Amp clamp on work lead shows 80 amps when cutting at a setting of 85, but my meter could be off a bit.
Torch is square to the work of course.
Tried manually adjusting the air pressure both up and down several psi and it only gets worse.
A call to Hypertherm's tech line got someone who thought it might be a problem with the pilot arc IGBT and suggested I return it to the place I bought it from for service. Place i bought it from suggests I call a repair shop about an hour away. Repair guy agrees it might be pilot arc related but of course has no parts in stock. He is certainly willing to check it out and repair it though. I guess I'm irritated at the attitude I received even though this thing is brand new with 1.7 arc hours on the clock. I would consider it pretty much DOA and yet I get to wait a couple weeks or more for someone to try and fix it.
Further experimenting today and it won't even fully cut through 3/4 A36 at 24 IPM and .060 cut height when travelling in the opposite direction to the angled arc. Again, this is with NEW consumables.
I have since talked to a different guy at the the shop I purchased it from. He is going to call Hypertherm in the morning. Hopefully someone can make this right in a hurry since it is a new machine.
Thanks for listening.
Marv
I've recently purchased a new PM 85 with machine torch to replace on older TD unit on my table. I ran a few cuts on 1/4" A36 and was quite impressed with the cut quality. Then I had a small part in 3/4" A36 to cut and thought that I may as well try this machine on that instead of cutting with oxy/fuel. I drew up my trusty test block in sheetcam and tried it out.The first 2x3 inch rectangle with two 3/4" holes was also quite encouraging even though I cut the holes at 24 ipm feedrate. I went ahead and cut the actual part and this is when the trouble started. The part ended up with about 7 degrees of bevel that gave the part a parallelogram shape from the end. I could actually see the arc being deflected towards one side of the table.
For the 3/4 I used genuine 85A consumables with all numbers on the parts matching the owner's manual numbers for the consumables. Pierce height .24", cut height .060". and 24 IPM. I never even bothered with THC on these small test parts since they are only a few inches long.
I assumed that I picked up a bit of piercing slag on the nozzle and changed it. Still have arc deflection. I decided to try 3/8" A36 with the 65A nozzle and book settings. Still have parallelogram problem. Tried 1/2" at both 65 and 85 amps with appropriate consumables and it still does it.
To make a long story somewhat shorter, this machine refuses to send an arc straight down through the plate. It's always pointing off in the same direction (usually towards the back of the table but it varies somewhat).
It does this at 45, 65 and 85 amp settings. At each power level I am using the proper mechanized shielded consumables although only the nozzle differs from one amperage level to the next. I have replaced everything including nozzle, electrode, retainer, swirl ring, and shield cap multiple times. Inspection of nozzles at 30x magnification reveals no reason for this behavior.
Pierce height and cut height are bang on verified by feeler gauge. When THC is on height is perfect as well, usually only 2 or 3 volts off of book specs. I have been using book specs for best quality through all this testing. Pierce delay is also by the book and is adequate to complete the pierce.
Air pressure never drops below 100 at machine inlet while cutting or doing a test flow from service screen even for several minutes. 1/2" ID line from compressor to coalescing filter and then a large desiccant dryer.
70 amp breaker and then 65 feet of #6 copper feeding this machine. Volts at 240 to 245 when idle and drop to 220 to 225 on service screen when cutting at 85 Amps.
Work cable is bolted directly to slat frame. Additional #2 cable and clamp from this point directly to workpiece. Amp clamp on work lead shows 80 amps when cutting at a setting of 85, but my meter could be off a bit.
Torch is square to the work of course.
Tried manually adjusting the air pressure both up and down several psi and it only gets worse.
A call to Hypertherm's tech line got someone who thought it might be a problem with the pilot arc IGBT and suggested I return it to the place I bought it from for service. Place i bought it from suggests I call a repair shop about an hour away. Repair guy agrees it might be pilot arc related but of course has no parts in stock. He is certainly willing to check it out and repair it though. I guess I'm irritated at the attitude I received even though this thing is brand new with 1.7 arc hours on the clock. I would consider it pretty much DOA and yet I get to wait a couple weeks or more for someone to try and fix it.
Further experimenting today and it won't even fully cut through 3/4 A36 at 24 IPM and .060 cut height when travelling in the opposite direction to the angled arc. Again, this is with NEW consumables.
I have since talked to a different guy at the the shop I purchased it from. He is going to call Hypertherm in the morning. Hopefully someone can make this right in a hurry since it is a new machine.
Thanks for listening.
Marv