[NorthridgeFab]

Well we are still fighting the divots and the main issue of having to cut at reduced feedrate to avoid it from just gouging the plate. Here is what we have tried to far:

Add a large air condenser
Motorgaurd's top of the line filter/sep system
Gauge at the back of the cutter to monitor psi
New Powermax85 cutter
Some torch, but we did try a new torch briefly with the same results
All new torch end parts (retainer, o-ring, electrode, etc...)

Anymore advise is appreciated.

[NorthridgeFab]

Here is a quick video of it https://picasaweb.google.com/lh/phot...eat=directlink

[jimcolt]

When I go to the link it is a picture, not a video.

Jim Colt

Here is a quick video of it https://picasaweb.google.com/lh/phot...eat=directlink

[jimcolt]

So....you have replaced the plasma, and tried a new torch, you are certain that the inlet pressure never gets below 105psi (when torch is flowing). I will 100% stand behing the speeds, heights, etc listed in the Hypertherm charts. They are correct.

So...this would lead me to believe that the speeds on your machine may be higher than the set speed.....or the height control is not maintaining the correct cut height (.06"). There is not much else to look at.

You could send me a piece of the material you are cutting...and a .dxf file....and I'll cut one or two of your parts on my Powermax85 at book specs to see what happens.

Jim Colt

[NorthridgeFab]

So....you have replaced the plasma, and tried a new torch, you are certain that the inlet pressure never gets below 105psi (when torch is flowing). I will 100% stand behing the speeds, heights, etc listed in the Hypertherm charts. They are correct.

So...this would lead me to believe that the speeds on your machine may be higher than the set speed.....or the height control is not maintaining the correct cut height (.06"). There is not much else to look at.

You could send me a piece of the material you are cutting...and a .dxf file....and I'll cut one or two of your parts on my Powermax85 at book specs to see what happens.

Jim Colt

I'll try uploading the video to another website. The only thing I can think of is some how there's moisture getting through the filter system. I'm thinking about buying a refrigerant cooler to cool the air. I'm just tired of throwing money at the problem, I'd rather know what the problem is and then spend the money to fix it.

I agree with you that the settings in the manual are accurate. The inlet pressure never drops below 100 while cutting. It does drop to 90-95 when it first fires, but it pierces and cuts fine at first.

The control system is CandCNC and I talked to Tom about the chance of it some how running faster than what sheetcam is putting in the gcode. He said he didnt see how that could happen. I'm positive the THC is maintaining the .06 cut height.

Thanks for the offer on cutting a test piece. Unfortunately we are under a deadline on these parts so I need to figure something out asap. Plus the parts are 72"x8", so kind of big piece of material to ship; but appreciate the offer.

[jimcolt]

The gear reduction ratio could be off......which would affect the programmed speed. You could do an 8' cut at a programmed speed and time it...just to be sure.

Also...the fact that pressure is dropping so much at the start concerns me. Try a direct short 3/8" id hose directly from the compressor....no filters or moisture traps. If the cut gets better...then you have an air restriction.

Jim Colt

I'll try uploading the video to another website. The only thing I can think of is some how there's moisture getting through the filter system. I'm thinking about buying a refrigerant cooler to cool the air. I'm just tired of throwing money at the problem, I'd rather know what the problem is and then spend the money to fix it.

I agree with you that the settings in the manual are accurate. The inlet pressure never drops below 100 while cutting. It does drop to 90-95 when it first fires, but it pierces and cuts fine at first.

The control system is CandCNC and I talked to Tom about the chance of it some how running faster than what sheetcam is putting in the gcode. He said he didnt see how that could happen. I'm positive the THC is maintaining the .06 cut height.

Thanks for the offer on cutting a test piece. Unfortunately we are under a deadline on these parts so I need to figure something out asap. Plus the parts are 72"x8", so kind of big piece of material to ship; but appreciate the offer.

[NorthridgeFab]

One of the reasons I'm thinking moisture is some how making it by the filter system is every once in awhile the consumables will short. Also, the arc seems very unstable and inconsistent. We have a large cyclinder to let the air condense in then is goes into a motorgaurd M-1000 filter system. All that is after the air travels through 75' of 1" piping.

I am thinking moisture is the problem but not sure how. Thats a long run of piping where the air is cooling the entire way. And this problem happens on the first cut, so all the air in the lines is room temp, not hot.

[NorthridgeFab]

The gear reduction ratio could be off......which would affect the programmed speed. You could do an 8' cut at a programmed speed and time it...just to be sure.

Also...the fact that pressure is dropping so much at the start concerns me. Try a direct short 3/8" id hose directly from the compressor....no filters or moisture traps. If the cut gets better...then you have an air restriction.

Jim Colt

Didnt think about the steps being off, I'll check that.

I think the pressure drop is because of the filter system. When this problem started we were using a 1/2" hose right from the compressor with a single water/oil trap and have virtually no pressure drop.

[jimcolt]

The electrode in your picture could be overheated from low air flow.

Jim

Didnt think about the steps being off, I'll check that.

I think the pressure drop is because of the filter system. When this problem started we were using a 1/2" hose right from the compressor with a single water/oil trap and have virtually no pressure drop.

[NorthridgeFab]

Ok did some tests and here are the pictures. I also uninstalled and reinstalled sheetcam and mach, also checked the steps and the motors are tuned dead on.

No filters, 25' 3/8" air hose right from compressor, 85A @ 40 ipm

[NorthridgeFab]

Filter system, 85A @ 40ipm. Also confirmed, there is 120psi going to the cutter. Drops to 112 when it first fires and when flowing is around 118-120.

[NorthridgeFab]

Filter system, 65A @ 30ipm. On all 3 pieces it never gouged the plate, but tried to a number of times. Kind of just spits back.

[NorthridgeFab]

Forgot, the torch is modified so I do not have to turn the machine on/off every time I change consumables. Just tied the wires together to keep to circuit closed. Yes, I understand the risks with this. I do not see how this would affect the cut. Also, the other torch we tested was not modified and it still messed up.

[NorthridgeFab]

Running out of ideas I mocked up my hand torch on the table. Seems like its cutting fine with it. I need to figure out to get the hand torch to fire off the CPC to run a better test, but sure seems like it's cutting good. I can't explain what the other machine torch we tried cut just as bad as the current one, but it did. Once I figure out how to get it to cut one it's own with the hand torch I'll confirm it is in fact cutting right then I guess the next step it to buy another machine torch. At this point I'll have enough in this fiasco I should have broke down and bought a HSD130!

[Torchhead]

Plasma flame "swirls" (rotates) as it comes out of the tip and behaves somewhat like a floppy rotating tool. Because of that the leading edge cuts different. It more pronounced on thicker material.