Thermal Dynamics Cutmaster 151 Problems

Hi all,
I'm working with an EZRouter that has a Thermal Dynamics Cutmaster 151 plasma cutter. It has a floating torch head. I think thats what it is called. The torch head is about a foot long and mounts to the z axis.

The problem is getting consistent cuts.
Here is how a cut goes most of the time.
Settings from the book start at 1/4 inch steel and just go thicker. There are no settings for anything less than 1/4 inch.

3/16 carbon steel.
Volts: 104
Amps: 100
Pierce: .190
Standoff: .150 (I'm assuming this is cut height)
Cutting speed is 70 in the book. I'm not 100% sure on this because I don't have the book in front of me.
THC is on.
Consumables are for 100 amp

I hit the run button and the torch will move to the first pierce point. The torch will move down, find the plate, move up to .190 and come on. It will pierce and then drop to .150. The THC does its thing at this point and I can see the torch height moving quite a bit in the DRO read out in Mach3. The THC-1000 control volts will fluctuate greatly on the THC readout. Eventually the readings all settle down. The DRO readout for the z axis might stabilize at .232, a large difference between what is programmed and what happens during the cutting.
While the cut is going on, about 1/2 the time the cut will be going smooth and suddenly the torch stops cutting through the plate. It will make an ugly scar in the plate and not pierce completely. It isn't consistent either. I can cut the same part 3 times in a row and won't mess up at the spot. It will mess up in other spots. 70 is way too fast to cut 3/16. I need to slow the speed to about 40 and then the torch will cut through 90% of the time but the slag on the back of the plate is horrible.
Any thoughts or suggestions are appreciated.

A technician came out today and determined that the problem was moisture in the air line. There is no dryer/filter between the compressor and the plasma cutter. The moisture in the system caused the start cartridge to erode because of what he called double arcing. There is a water trap of sorts on the plasma cutter but it is largely ineffective.
I haven't been able to test the results yet. I still have to install a water trap/filter/dryer, whatever they are and then test it.
Hopefully this information might help someone else.

Moisture in the compressed air system is the the most common source of short consumable life and poor cut quality....especially during hot humid summer weather. Most plasma system manufacturers suggest filtration and water separation systems be put in place before using any air plasma system.

-Drain your air compressor tank daily....or install an automatic drain (best)
-A refrigerated air dryer with an auto drain is the best fix.....and should actually be used for almost all air tools to eliminate moisture and increase performance and life. These units chill the air as it exits the compressor, which condenses moisture, them separate the moisture. There are many second hand units available (craigslist, ebay) as these units are used in auto body shops, etc. As much as I hate to promote it....Harbor Freight has a unit that is reliable and works very well for under $400, and can handle up to 12 cfm of air flow..most air plasma systems draw between 4 and 8 cfm.
-There are coalescing type filters that work.....if you specify components for an air system that are compatible with automotive spray paint applications...they generally will work well for plasma.

Moisture in plasma air changes the physics that are ocurring inside the plasma torch, resulting in poor cut quality, rapid electrode erosion, and potential for torch failure.

Jim Colt Hypertherm

Quote:

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Originally Posted by Shanghyd

Hi all,
I'm working with an EZRouter that has a Thermal Dynamics Cutmaster 151 plasma cutter. It has a floating torch head. I think thats what it is called.
3/16 carbon steel.
Volts: 104
Amps: 100
Pierce: .190
Standoff: .150 (I'm assuming this is cut height)
Cutting speed is 70 in the book. I'm not 100% sure on this because I don't have the book in front of me.
THC is on.
Consumables are for 100 amp

I hit the run button and the torch will move to the first pierce point. The torch will move down, find the plate, move up to .190 and come on. It will pierce and then drop to .150. The THC does its thing at this point and I can see the torch height moving quite a bit in the DRO read out in Mach3. The THC-1000 control volts will fluctuate greatly on the THC readout. Eventually the readings all settle down. The DRO readout for the z axis might stabilize at .232, a large difference between what is programmed and what happens during the cutting.
While the cut is going on, about 1/2 the time the cut will be going smooth and suddenly the torch stops cutting through the plate. It will make an ugly scar in the plate and not pierce completely. It isn't consistent either. I can cut the same part 3 times in a row and won't mess up at the spot. It will mess up in other spots. 70 is way too fast to cut 3/16. I need to slow the speed to about 40 and then the torch will cut through 90% of the time but the slag on the back of the plate is horrible.
Any thoughts or suggestions are appreciated.

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You might try droping your voltage a couple of volts, the THC should respond by dropping the cut height closer to what you have programmed.
Is the torch not cutting through because it raised up to far or was it still at the .23 cut height. You can set Mach 3 ,the "THC Max" to say .25, the will hold the torch at that max distance and you can complete your cut anyway.
I use the Harbour frieght air dryer and a Ford toilet paper filter on my Cutmaster 52 and between the 2 it works well. I just cut some 3/16 Stainless for grill grates, 60 amps at 20ipm, it cut grate:D with very little slag.
You also could look on the Cutmaster web site in the literature area, they have manuals for other cutters that give speeds and voltages for thinner materials. You will want to drop to 40 or 60 amps but it will get you in the ballpark

Good luck
Mike

Here are some cut speeds and settings From my Cutmaster 52 for thinner materials. Change your amps, volts and tips to match, they should work

Mike