taper on plasma cuts using torchmate machine.

I would like some feedback from anyone . . . This problem is driving me nuts. I have been cutting flanges from 3/8 steel with my torchmate cnc plasma with a powermax 900 plasma machine. i have checked my amperage and voltage settings as well as my speed. everything seems to be about par. The problem is that i am getting a taper on 2 sides of the part, but the other side has almost no taper. I would assume that this would be the nozzle that the plasma comes out of. So i did a test. I cut 2 3 inch by 3 inch squares. one with my old nozzle and one with a brand new nozzle. I got the same result from both, 2 sides have a 1-2 degree taper and 2 sides have an 8-9 degree taper. my table is completely square with my torch also . . . . does anyone have any idea what could be?

This is what will cause the type of taper (varying) with a plasma cutter:

1. Damaged nozzle orifice. This is almost always caused by piecing too close to the plate. The Powermax900 should be using shielded consumables (check your operators manual for correct part numbers) and you should be piercing the 3/8" at about .15"....with and adequate pierce delay to allow full pierce befor any machine movement...then you should be cutting at .06". If you did one pierc too close on a new nozzle...the nozzle is likly damaged and will cut with varying angularity. Posting some focused, closeup pictures of your used nozzle will allow me to instantly determine if this is the case.

2. A missing or worn o-ring on the torch body will cause varying angularity.

3. A worn retaining cap will cause varying angularity

4. a worn swirl ring will cause varying angularity

5. Varying cut height will vay the angularity.

6. a worn out or leaky torch body will cause varying angularity.

Jim Colt Hypertherm

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Originally Posted by nauticwaterjet

I would like some feedback from anyone . . . This problem is driving me nuts. I have been cutting flanges from 3/8 steel with my torchmate cnc plasma with a powermax 900 plasma machine. i have checked my amperage and voltage settings as well as my speed. everything seems to be about par. The problem is that i am getting a taper on 2 sides of the part, but the other side has almost no taper. I would assume that this would be the nozzle that the plasma comes out of. So i did a test. I cut 2 3 inch by 3 inch squares. one with my old nozzle and one with a brand new nozzle. I got the same result from both, 2 sides have a 1-2 degree taper and 2 sides have an 8-9 degree taper. my table is completely square with my torch also . . . . does anyone have any idea what could be?

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I changed all my consumables on the torch and it helped. I still have a little taper, but not as much. My main problem now is the holes. I am cutting a 3/8 hole from 3/8 steel. I definately cannot get the holes to cut proper. They all look good on the top side of the material, but they taper in on the bottom. I spoke with the person who sells our consumables and he said the powermax 900 does not have the power to do small holes good. Is this true?

Your Powermax900 has adequate power to pierce up through 1/2", as long as you have a height control that can pierce at the proper pierce height, then index down to cut height.
Use the 55 amp shielded consumables in your torch...then the following procedure to get the best holes:

-Set the pierce height at .15"
-Set pierce delay time adequately so the arc fully penetrates the plate before any x or y movement.
-Set cut height at .06"
-Set the cut speed at 50 to 60% of the recommended book speed (from your powermax900 operatos manual.
-before piercing...spray a small amount of mig welding anto spatter spray on the top of the plate....this helps to eject the slag pile that distorts the arc...making the bottom of the hole out of round.

Keep in mind: This is an air plasma....and it is not the latest technology.(you can upgrade the torch with a Duramax torch from Hypertherm....will cut cleaner and squarer). Air plasma torches always produce some taper. Once you get it dialed in....a 3/8" hole will have a bottom dimension that is smaller than the top....by approximately .050" to .060". For bolt holes...either program the hole dimension that much larger...or drill the hole after cutting with a cobalt or carbide drill bit. Inspect the nozzle orifice before cutting...make sure there are no nicks, burns or out of roundness....damage to the noozle is caused by piercing too close...even one time. A damaged nozzle will cut with varying angularity.

The attached photo shows holes cut with a Powermax with the newer Duramax torch on 1/4" steel...the holes are 1/4", 5/16", 3/8" and 1/2" diameter...and are as cut using the above technique.

Jim Colt

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Originally Posted by nauticwaterjet

I changed all my consumables on the torch and it helped. I still have a little taper, but not as much. My main problem now is the holes. I am cutting a 3/8 hole from 3/8 steel. I definately cannot get the holes to cut proper. They all look good on the top side of the material, but they taper in on the bottom. I spoke with the person who sells our consumables and he said the powermax 900 does not have the power to do small holes good. Is this true?

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I have the RT60M cutting torch which i was told was an upgrade from the regular mecanized torch. Also, i have my pierce height at about 0.15, but my cutting height is about 0.18. The problem with a lower height is that right after the pierce the torch wants to dive lower than the pierce height an it usually hits the material, which moves my material and ruins my nozzle. I have to increase my cut height to avoid this. Also, i am having trouble with 3/8 and above. steel up to 1/4 does not have much of a problem.

On your Torchmate height control there is an arc voltage delay setting....that needs to be set to a long enough time so that the arc voltage control never becomes active on any hole under about 1-1/4" diameter.

Your Torchmate machine does not have the ability to get up to speed on holes under this diameter....and since it effectively is not up to speed...when the arc voltage control activates it moves the torch closer to the plate in an attempt to correct the voltage.

Find that delay....and set it to about 3.5 to 4.5 seconds. Now your AVHC will come down, torque sense the surface, retract to the pierce height (set by you), then once the pierce delay timer times out (different than the arc voltage delay) the torch should move down to the cut height (also set by you)....it will then start moving through the hole profile.....and the arc voltage feedback control will stay off.....which it should....no diving!. On outside profiles that take longer than the 3.5 to 4.5 seconds...your arc voltage control will activate after that time....if the torch then gets too close.....increase the voltag until the height remains at .06", if too high, decrease voltage until at .06".

Setting the height higher than .06" to stop the torch from diving is making the angularity worse. Too high equals increased edge angularity.....the height control is there to maintain correct height just for that reason.

The RT60M (machine torch) is newer than the original PAC123 that came with your 900, but is about 12 years older in design as compared to the Duramax torch. The RT60 is a great torch....and once you get the height control maintaining the correct height....you will be happy with the cut.

Unfortunately...the Torchmate systems don't have the ability to automatically freeze height during cornering or slowdown....and cannot do it through the Machine code files either. Most other machines auto freeze whenever the cut speed is less than about 80% of the programmed speed....this eliminates the dive. With your...the arc voltage delay is the only way to solve it.


Jim Colt

Quote:

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Originally Posted by nauticwaterjet

I have the RT60M cutting torch which i was told was an upgrade from the regular mecanized torch. Also, i have my pierce height at about 0.15, but my cutting height is about 0.18. The problem with a lower height is that right after the pierce the torch wants to dive lower than the pierce height an it usually hits the material, which moves my material and ruins my nozzle. I have to increase my cut height to avoid this. Also, i am having trouble with 3/8 and above. steel up to 1/4 does not have much of a problem.

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I called torchmate and they told me there is no way to set the voltage delay setting. I am going to do a few test cuts at a lower voltage (which lowers the cut height) to see if i get better results.

Thats funny...you can set the arc voltage delay on mine....maybe you have an older software version? Can you set the avhc in manual mode...just use the pierce height an cut height.....but in manual it should not go into arc voltage control at all. See how the cuts look in this mode.

Jim

Quote:

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Originally Posted by nauticwaterjet

I called torchmate and they told me there is no way to set the voltage delay setting. I am going to do a few test cuts at a lower voltage (which lowers the cut height) to see if i get better results.

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I just did a test. In 3/8 steel, I did a 3 by 3 inch circle with a 3/8 hole, a 1/2 hole, and a 1 inch hole. I set the height control in manual mode and i turned the speed down. I had my amperage set to 55. The holes cut about 10 inches a minute while the square did about 15 IPM. I measured the height while it was cutting and the tip was about 0.060 to 0.080 above the material. Here are my results. Is this normal? or can i get it even better? Also, my automatic height control is from 2007 so maybe that explains why i can't change my voltage delay setting. By the way thanks for taking your time to help me out. . .

Looks pretty good....I'm assuming you are using the machine shield, and 55 amp consumables? The .080" height will cause more taper than .060". Considering you are using an older generation plasma (over 14 years old) and an older generation torch (design is about 12 years old)....and basically no hight control functionality...you are doing pretty good.

Here is my edge angularity on 3/8" with the Powermax 45 torch at 45 amps, these were cut on my PlasmaCam with the height control on....at exactly .06" off the material:

Quote:

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Originally Posted by nauticwaterjet

I just did a test. In 3/8 steel, I did a 3 by 3 inch circle with a 3/8 hole, a 1/2 hole, and a 1 inch hole. I set the height control in manual mode and i turned the speed down. I had my amperage set to 55. The holes cut about 10 inches a minute while the square did about 15 IPM. I measured the height while it was cutting and the tip was about 0.060 to 0.080 above the material. Here are my results. Is this normal? or can i get it even better? Also, my automatic height control is from 2007 so maybe that explains why i can't change my voltage delay setting. By the way thanks for taking your time to help me out. . .

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Jim,
My shop is about to buy a powermax 85, and we have a shop nearby that wants to take our rt60 torch off our hands. will the rt60 fit on his powermax 800 so we can get a few bucks back twards our new machine?

There are a few different versions of the RT60 torch with different connectors to fit different power supplies. If the connectors at the power supply end are the same...then it will work on the Powermax800. Some of the early systems used a quick disconnect and some used hard connections.


Jim Colt

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Originally Posted by nauticwaterjet

Jim,
My shop is about to buy a powermax 85, and we have a shop nearby that wants to take our rt60 torch off our hands. will the rt60 fit on his powermax 800 so we can get a few bucks back twards our new machine?

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We are now using our new powermax 85 which cuts soo much better than the old 900. My taper is about 2 degrees on all sides accept for one side which stays constant every time at about 5 degrees. The height seems good . . . Any possible thought on what the problem could be?

Have you put a square from torch to plate on both axis? If you are 100% sure it is perfectly square to the plate in all directions....then rotate the torch 90 degrees in its holder and do a test cut before and after. If the issue travels with the torch...then you need to change the consumables one at a time....and do the test cut again. Nozzle first, electrode second, shield third, swirl ring fourth and lastly the retaining cap. If the angle stays in the same quadrant after rotating the torch....then the torch is out of square to the plate.


Jim colt

Quote:

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Originally Posted by nauticwaterjet

We are now using our new powermax 85 which cuts soo much better than the old 900. My taper is about 2 degrees on all sides accept for one side which stays constant every time at about 5 degrees. The height seems good . . . Any possible thought on what the problem could be?

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Jim,

Previously you stated that the bolt holes have to be a cut a good amount larger than the bolt size. What sizes were cut on the sample that is displayed in the picture with the bolts sliding through your holes. I am cutting with a Powermax 125 on 3/8'' plate creating 1/2'' bolt holes and would like to know what kind of over sizing I should expect to have to implement. Additionally, should I expect to see better cuts while using the higher (125A) amperage settings on the power supply or with the lower (45/65/105A) settings?

Thanks.