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Tuning THC

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02RedWS6TA
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Joined: Wed Jan 22, 2014 6:44 pm

Tuning THC

Postby 02RedWS6TA » Fri Apr 18, 2014 5:16 pm

Hi,

I'm having some problems tuning my THC on my Precistion Plasma/CandCNC table. Cutter is a PM45 using a hand torch, changed consumables today to rule that out.

Just doing straight line cuts to get a base volt it bounces between 107-120 volts but holds 108 for most of it. I can cut decent with THC turned off as long as the sheet doesn't warp. Although much slower than the stated speed in the HT manual.

On 11ga I have to cut around 35IPM to get it to cut all the way through the entire time which ends up warping the piece pretty quick. I'm not sure if the slow cut speed is contributing to the THC going crazy when it turns on or not. Plunge rate is set to 40, pierce delay to .4, and THCD is set to 1.5 to give it plenty of time to start the cut. Pierce height is .15 and cut height is .065. Once it starts the cut it's fine but as soon as THC takes over it slams down or shoots off the table and never corrects.

I've posted on CandCNC support boards and he was replying at first but hasn't replied it a few weeks. I work during their business hours so not really sure where else to go for ideas or what to try. New to CNC so any ideas to get it cutting would be great.

Thanks.

jimcolt
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Re: Tuning THC

Postby jimcolt » Sat Apr 19, 2014 9:47 am

If you cannot achieve the speeds stated in the Powermax45 operators manual....then you should probably solve that problem first. The Powermax45 will easily cut at the optimum speeds listed if you are using the correct consumables, air pressure, amperage and torch to work distance.

- Make sure the physical cut height is .06" during steady state cutting.....arc voltage does not matter...the physical cut height does. Too high and you will not cut through.

-Make sure you are following the specs in the mechanized cut charts (even though you are using a hand torch)

-Make sure you are using the machine torch shield, not the hand torch shield (designed for drag cutting....if used with a standoff the torch will be way too high off the plate, and you may not cut through).

- Ensure that you are setting the cut air pressure correctly. It will help idf you install a pressure gauge right at the air inlet, then turn the amperage knob fully counterclockwise (this makes the air flow) and adjust the regulator so that the front panel LED's are satisfied. Make sure inlet pressure (measured at the rear inlet, not back at your compressor) stays above 85 psi while air is flowing.

-Make sure your front panel mode switch is in the "cut" position. If in expanded metal or gouging mode you may not cut through the material at book specs.

Once the plasma is sorted out (do test cuts with THC off and a fixed torch height) and it is cutting as designed....then you should work with CandCNC to determine proper settings with the THC.....I suspect it may just be some background settings....but I am not familiar with this particular system.

Jim Colt Hypertherm


02RedWS6TA wrote:Hi,

I'm having some problems tuning my THC on my Precistion Plasma/CandCNC table. Cutter is a PM45 using a hand torch, changed consumables today to rule that out.

Just doing straight line cuts to get a base volt it bounces between 107-120 volts but holds 108 for most of it. I can cut decent with THC turned off as long as the sheet doesn't warp. Although much slower than the stated speed in the HT manual.

On 11ga I have to cut around 35IPM to get it to cut all the way through the entire time which ends up warping the piece pretty quick. I'm not sure if the slow cut speed is contributing to the THC going crazy when it turns on or not. Plunge rate is set to 40, pierce delay to .4, and THCD is set to 1.5 to give it plenty of time to start the cut. Pierce height is .15 and cut height is .065. Once it starts the cut it's fine but as soon as THC takes over it slams down or shoots off the table and never corrects.

I've posted on CandCNC support boards and he was replying at first but hasn't replied it a few weeks. I work during their business hours so not really sure where else to go for ideas or what to try. New to CNC so any ideas to get it cutting would be great.

Thanks.

02RedWS6TA
Posts: 29
Joined: Wed Jan 22, 2014 6:44 pm

Re: Tuning THC

Postby 02RedWS6TA » Sat Apr 19, 2014 10:53 am

I did not know about switching the shield. I will try that today and report back. Thanks for the quick reply.

02RedWS6TA
Posts: 29
Joined: Wed Jan 22, 2014 6:44 pm

Re: Tuning THC

Postby 02RedWS6TA » Sat Apr 19, 2014 1:46 pm

Sanded down my hand torch shield and ordered a new machine torch one. Ran some cuts today, cuts great with the THC off now where as before it cut like crap. Still can't dial in the THC.

Cut 14ga at 120IPM and will speed it up on my next cuts.

Once I get the new shield and get it a little more dialed in on speed I'll start tying to tune in the THC. Just glad I can cut parts now.

Thanks Jim.

02RedWS6TA
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Re: Tuning THC

Postby 02RedWS6TA » Tue Apr 22, 2014 9:54 pm

I went out to do some more cutting today and the plasma was having problems cutting even with the THC off. It ran great all weekend cut a couple 4x8 sheets out and didn't really have any problems as long as I didn't go thicker than 14 gauge. I tried on 11 gauge and it just wouldn't cut at all and would eat the nozzles pretty much instantly.

Now today when I went out I tried cutting on 14 gauge and it would cut for a bit then wouldn't cut all the way through but leave a wet line where it traveled. I was only running at 120ipm and I believe it's rated for 280 on this thickness. I am not running a regulator on my compressor so I have to regulate the air with the plasma, could this be causing me issues? I ordered a regulator today. I didn't run one all weekend so I don't see how this could be the problem.

It also melted a nozzle in about 30 seconds worth of cutting. I have it set to .060 but with no THC it obviously will vary on it's distance above the sheet. I don't know if it's getting too close or what but this didn't seem to be an issue over the weekend. After trying to cut for about 30 seconds on a brand new nozzle there was no tip left on it at all. It didn't appear to be pressing into the sheet at all but obviously it's very close. I'm not sure if I took too much off the shield when I ground it down but the machine one comes tomorrow.

I'm running a motor guard M60 filter on the compressor and just a throw away filter on the pack of the plasma trying to get dry air to it.

Largemouthlou
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Re: Tuning THC

Postby Largemouthlou » Wed Apr 23, 2014 10:36 am

Wait for the proper parts for the torch to come in. What post processor are you using in SC if your using SC and have you set your switch offset yet? Only thing that gets calibrated on my older DTHC is the rate which I have srt to 22%.. Are you using a floating head or feather touch?
1250 hypertherm
4 X 8 Precision Plasma
CandCnC electronics

02RedWS6TA
Posts: 29
Joined: Wed Jan 22, 2014 6:44 pm

Re: Tuning THC

Postby 02RedWS6TA » Wed Apr 23, 2014 12:08 pm

Yes I set the offset. It was like .0812 or something. I'm using the post that candcnc sends with their package. The tip should be here today. If I can't tune it today or get it to cut I'll call them tomorrow.

I have the stuff to set up the feather touch but right now I'm using the floating torch and a limit switch.

02RedWS6TA
Posts: 29
Joined: Wed Jan 22, 2014 6:44 pm

Re: Tuning THC

Postby 02RedWS6TA » Wed Apr 23, 2014 8:35 pm

The machine torch tip solved the cutting speed/issues but the THC is still not working but I'll do some more tuning now that it's running better.

Thanks for the help so far. Start of solving my problems.

jimcolt
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Re: Tuning THC

Postby jimcolt » Thu Apr 24, 2014 8:04 am

I believe it is the machine torch shield that you changed.....as there is no part on a Hypertherm torch called a "tip". The hand torch shield is designed to maintain the correct distance betwen the nozzle and the material being cut when drag cutting. So, if you use the hand cutting shield on a cnc machine with a standoff (the manual says the standoff should be .060" for best cut quality) then you are running the torch to work at a distance that is .060" too high....which affects cut edge angularity as well as forcing you to slow down (because the arc may not fully penetrate)....which produces warpage and dross.

Using the hand shield is a common mistake when using a Hypertherm hand torch on CNC machines because all hand torches come with the hand (drag) shield. If using a hand torch on a machine always follow the machine cutting specs in the operators manual and be sure to use the consumable parts specified for a machine torch.

Get that height control sorted out with the guys at CandCNC.com and you will be well on your way to nice plasma cuts!


Jim Colt Hypertherm

02RedWS6TA
Posts: 29
Joined: Wed Jan 22, 2014 6:44 pm

Re: Tuning THC

Postby 02RedWS6TA » Thu Apr 24, 2014 11:34 am

Thanks again Jim. It's at least cutting now. I have a backlog to get out then it'll be onto getting the THC. Here's a pic I cut last high.
Image

Brand X
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Re: Tuning THC

Postby Brand X » Thu Apr 24, 2014 12:23 pm

I would make sure your post offset is set correctly. Meaning using a thick steel plate to check it. Run a file, with the torch/THC off, and measure real cutting height. Just hit feed hold. Might have to hit the torch switch to get it that far in the code. Then you will have the correct offset, and that can be different manually jogging the offset to find the # you need. Open up SheetCam, and look at the post processor you are using.It probably will have the offset in MM. Needs to your # in MM.. You must have the same # in your Profile screen but that will be in inches. Add some more delay to your THC also. Lower your THC rate if you still have problems..Click the Anti dive on too.. Generally the default at 60% is fine..

Largemouthlou
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Re: Tuning THC

Postby Largemouthlou » Fri Apr 25, 2014 6:46 am

02RedWS6TA wrote:Yes I set the offset. It was like .0812 or something. I'm using the post that candcnc sends with their package. The tip should be here today. If I can't tune it today or get it to cut I'll call them tomorrow.

I have the stuff to set up the feather touch but right now I'm using the floating torch and a limit switch.


May want to recheck the offset.. mine is in the area of .4168 or something like that, yours seems way too tight. Did you use the piece of paper method and have z dro zeroed out before checking?
1250 hypertherm
4 X 8 Precision Plasma
CandCnC electronics

Brand X
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Re: Tuning THC

Postby Brand X » Fri Apr 25, 2014 12:40 pm

Depending on manual jog speed of the Z, the offset # can be different. Just make sure you jog at the same speed the machine uses in Mach (Motor /home soft limit speeds at 20 %) If your Manual jog speed is different then getting the Offset # to match can be a challenge. If you test the cut height (lets say you machine is set for .060) then running a test without Plasma, and THC on will make sure your offset is exactly correct. Thick plate that does not flex will give you the exact number you should be at. I fought that one when I upgraded my z switch and floating head slide. Along with the New DTHC1V. Once the offset was correct, and the MM setting in the post processor. it was good to go. If I punch in .060 for cut height in my parameters . it now comes in at .060. Meaning the offset is exactly correct.

02RedWS6TA
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Joined: Wed Jan 22, 2014 6:44 pm

Re: Tuning THC

Postby 02RedWS6TA » Fri Apr 25, 2014 7:42 pm

I got it working tonight. I called candcnc. I'm dumb is about what it equals. Had to switch up/down direction in the hub controller... ugh I'm not sure how I missed that.


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