[will_eng]

I have a Hypertherm 1250 with a custom built table. I am running air in at 90 to 100 psi through a deliquescent air dryer. Which in itself is a bit of an experiment. I know one other person on here is or was using the same dryer. I would like to know if anyone else has had experience with deliquescent being different than "dissicant".
I am running the recommended cut parameters set out by hyperthem through sheetcam. And minding the direction I am cutting for the "good" side. However my cuts are angled line this // .

I probably had some bad starts and have tryed new electrode/nozzel for a given cut setting thematerial zero carefully so that my pierce height of .150 and cit height of .063 would be right. But I still don't get a a cut that is straight on all sides of the male or female part. The torch is straight in its holder and the angle changes when I rotate the torch or change the consumables.

Here are some cuts in 1/2" steel using 60amp consumables, cutting at 27ipm. Nozzel still looks round and no nicks, electrode is hard to measure bit does not look like the pit is even close to .040" deep.

Any thoughts, I appreciate it.

[will_eng]

Note: it's hard to tell from the pictures but I can get one side of the hex straight. The others are beveled in the same direction, on an inside or
outside cut.

[WSS]

Try a new swirl ring and a new shield. To find the problem, do one at a time. Around here when that starts, we usually change everything and get back to work. If you have the time and material, you can pinpoint the problem and save $$ on consumables. I have also had problems with over tightening the retainer and causing similar problems, I think it squeezes the swirly too much and binds the electrode. Oh, ya, recently I had some strange rubber oring looking material find it's way to the exhaust holes and causing variable angles.

Good Luck!
WSS

[C.Michael]

I have the same 1250..using Mach 3 and THC 300 from Campbell..I had the same problem with high taper..Your torch is too high creating the taper as it runs..try this..during the middle of the cut, hit the stop button on mach and this should stop movement and cut the torch off..Then measure your torch height off the table with a stack of feeler gauges..is it .063 like it should be? I bet it is closer to.1 of an inch..turn your torch height voltage setting down to lower the torch down maybe 2 volts at a time with each new test run..
With the thc 300 that I have, it only takes just a touch of a rotation of the knob to make the difference in voltage reading..You should be able to make a cut, where the piece fall through to the floor after it is done. just adjustments of 1 or 2 volts..And you will know when you hit it because it will be a beautiful cut..

Then what I do to capture the exact location of the knobs is take a digital photo of the THC panel for future reference..showing the exact position of the knobs..Because different steel thicknesses require different knob settings and the photos will keep the record of it..

[WSS]

I have the same 1250..using Mach 3 and THC 300 from Campbell..I had the same problem with high taper..Your torch is too high creating the taper as it runs..try this..during the middle of the cut, hit the stop button on mach and this should stop movement and cut the torch off..Then measure your torch height off the table with a stack of feeler gauges..is it .063 like it should be? I bet it is closer to.1 of an inch..turn your torch height voltage setting down to lower the torch down maybe 2 volts at a time with each new test run..
With the thc 300 that I have, it only takes just a touch of a rotation of the knob to make the difference in voltage reading..You should be able to make a cut, where the piece fall through to the floor after it is done. just adjustments of 1 or 2 volts..And you will know when you hit it because it will be a beautiful cut..

Then what I do to capture the exact location of the knobs is take a digital photo of the THC panel for future reference..showing the exact position of the knobs..Because different steel thicknesses require different knob settings and the photos will keep the record of it..

When the torch is too high the taper is usually equal on all sides, his leans which indicates a physical problem with the arc.

[will_eng]

I have been very careful about setting my height for each cut. However I have a THC on the way. I will try stopping the cut and checking the height mid cycle though.

What i did do though is adjust the torch angle based on the arc not the torch body. Along with using corner loops on sharp corners I can get a part that has close to equal draft on all sides (2-5 deg). However I worry I will be in trouble if i rotate the torch or change consumables. Note I was using new consumables almost after every test (my swirl ring is also a new item and looks good).

for cutting parts with rounded corners my cut still really lags behind on the corners and I get a bevel that is over 5 deg. I tried a post that slows down the feed in the corners but did not show a lot of improvement.

In general I can adjust my feed rate to get lag lines that are close to vertical and little slag, but I can get away from the whole cut lagging behind on the first corner unless I use corner loops.

I know 3 deg is the standard for draft but is this supposed to be a worst case like in the corners? My best cut is around 3 deg on a straight.

[WSS]

I have been very careful about setting my height for each cut. However I have a THC on the way. I will try stopping the cut and checking the height mid cycle though.

What i did do though is adjust the torch angle based on the arc not the torch body. Along with using corner loops on sharp corners I can get a part that has close to equal draft on all sides (2-5 deg). However I worry I will be in trouble if i rotate the torch or change consumables. Note I was using new consumables almost after every test (my swirl ring is also a new item and looks good).

for cutting parts with rounded corners my cut still really lags behind on the corners and I get a bevel that is over 5 deg. I tried a post that slows down the feed in the corners but did not show a lot of improvement.

In general I can adjust my feed rate to get lag lines that are close to vertical and little slag, but I can get away from the whole cut lagging behind on the first corner unless I use corner loops.

I know 3 deg is the standard for draft but is this supposed to be a worst case like in the corners? My best cut is around 3 deg on a straight.

Even a new swirl ring that has a nick internally or has been over tightened can cause trouble. THe shield can also be a leaning arc source. Your electrode does not look like water is a problem but try the white paper trick and turn the amp dial all the way down and let it blow on a piece of paper to see if it gets wet. We also change out the retainer fairly often, every 30 nozzles or so.

My LWS rep just dropped off a new 100amp duramax torch for me to try! It is 25' so I will have to hang it over the table to test it, but looking forward to it.

[jimcolt]

On small features it is important that there is adequate pierce delay time....and that the lead in is as long as possible. This allows for the plasma arc to stabilize...and allows for the height to index from pierce height to cut height. Cut height must be at .060" with the shielded Hypertherm consumables....and pierce height must be at the book setting for the material thickness. It is also a good rule to cut small features (under 1-1/4" holes as an example) at 60% of the suggested cut speed...this will help to square the edges.

Also....you are using an air plasma. These units (as compared to high powered C02 lasers, abrasive water jet, and high definition plasma....will cut with more edge angularity and edge angularity variation. With perfect height control (in my opinion necessary)...and following my recommendations above...you will achieve edge angularity (on 3/8" and 1/2" steel) in the 2.5 to 3.5 degree range. Angularity will be more severe on thinner materials...and less severe on thicker materials on a properly set up/properly running system. Air plasma systems are limited to the use of air as the plasma gas...and are designed to be affordable....at the expense of shorter consumable life and lesser cut quality as compared to industrial high definition plasma systems....and cost about 1/10ththe purchase price of a high definition system.

The newer Hypertherm Duramax torch (available for the older Hypertherm machines, and standard on the newer Powermax 65, 85 and 105) will improve edge angularity and consistency due to some new technology that increases energy density.

Best regards, Jim Colt Hypertherm