intermittent cut and inconsistent torch misfire

[elvenhome21]

I am having a couple random issues that im not sure where to start looking for the issue.
the first time I cut this duck I had a torch misfire on the first pierce, I dont believe its the THC becasue it was for sure less then .200 off the plate visually. If I hit the torch button off and on it will refire and hit go and will continue to run fine. Until it gets to a random inside cut where the torch will blow out and re fire a second or so later.

I ran 2 of these pieces and it blew out in 2 different spots and at different speeds.
in the video it blows out at :57
http://youtu.be/Km56FPcC4vM



Machine:
Precision plasma
bladrunner
mach3
sheetcam using mp1000 THC scriber post
HT Powermax 45 w/MT almost new consumables
.12 pierce .06 cut height

[elvenhome21]

Another issue im having is when I try to start mid program and have the head lifted above the plate when i click run it gives me the start position values and i click run and the z will raise up another 1/4 inch or so and that will act like its zero point, and wont do a touch off zero. So it will try and cut a inch off the plate.

Any suggestion on how to fix this

[elvenhome21]

anybody?

[Stout]

Strange how the arc goes out and then just comes back on. I don't even see a pilot arc in the video.

Does your machine typically stop on a loss of arc? If it does then your not getting that signal from the plasma unit, so that looks like the culprit. Does the PM45 have that switch on the front for expanded and regular cutting? Might check the position also.

[sodfarmer]

Try this link for restarting. Arclight uses CandCNC. Also some good videos for using Mach 3 and plasma cutting.

http://arclightcnc.com/training.html

[elvenhome21]

i turned the settings off for stop on fault and arc loss because I was having some weird issues with the torch not firing automatically at the first pierce, but when I hit run again and click torch on it will work normally for the rest of the program. Im thinking that might of had to do with using the wrong post in sheetcam.

The arclight videos ive watched numerous times but they dont go into a lot of specific detail for plasma issues.

[Cbrbarnes]

I had a similar problem with my arc going out and it took a long time and research to figure it out. I had a bad spring in the air solenoid. Until I get a better solenoid, I took the spring out and stretched it a bit and all has been well. I wouldn't trust this fix for a big project or an expensive piece of material but worth a shot. Hope this helps.

[elvenhome21]

Your on to something there. I looked at the video again and the air actually stops when it blows out. Definitely worth looking into.

Thanks for the advice

[BTA Plasma]

It is most likely PC related. Get a Dell Optiplex 620 with a "D" dual pentium 4 and you will not have that issue.

[elvenhome21]

thats pretty much what i have. Dell Optiplex GX280

[BTA Plasma]

thats pretty much what i have. Dell Optiplex GX280

280 is not a 620, the 620 has a much better motherboard. We have had intermittant issues with 280s and you should really upgrade as soon as possible. The motherboard doesnt allow enough resources for operation with Mach 3 flawlessly on that 280. They are known for some really bad issues and are what we found to be the sole problem with intermittant torch stops and starts. We use the D core pentium 4 chipsets on mini towers and full towers and it operated Mach perfectly.

[The Hack House]

Might be nothing but worth saying, make sure the ground from the plasma tourch is good.

[plasmapros]

It is a good idea to have a pressure gauge on the inlet side of your plasma cutter so you can be sure your pressure is not dropping below 80psi which is common if you have a restrictive filter that cannot flow more air than the plasma cutter is using.

[abmagrum]

I had the same problem. you have to put a gauge at the back of the cutter . A MUST.

what I did was get a piece of scrap ON . THEN cut some thing small out.

but as soon as you hit run . run to the back of youre plasma cutter. watch the gauge the whole time not the part.

you will start out 110-130 psi then each line you watch how far the pressure drops .you really want to be in the 90's psi 80 will cut pretty good low 80's or high 70's you will have problems . trust me I know.

check out my post hypertherm miss fire. jim put a picture of the air gauge set up. up. low pressure makes it do all

kinds of bad things. I had 120- 130 psi but I dropped to the 70's cutting a 4 inch butterfly beefed up the air cuts perfect. read all jims replys there is tips to check for other problems

[elvenhome21]

Ground should be good. Im clamped directly to clean steel.

air pressure shouldn't be an issue. Im running a 3/8 id air hose to the cutter, along with a 8 gallon air tank tee'd into the plasma cutter to handle the air surges. pressure gauge on the tank never gets below 100 psi.

As for the computer I just bought it as a refurbished unit with a clean win xp install. The only thing it has a problem handling is running inkscape when doing a simplify nodes on a very detailed part.

[elvenhome21]

only thing I noticed lately is when I turn the plasma cutter on it makes a high pitch electronic squeal/krackle, kinda like a CRT TV

[jimcolt]

That is a normal sound for the Powermax45.

If your pressure gauge back at the compressor is reading 100 psi.....it is highly likely that the pressure at the inlet of the plasma is substantially lower than that while air is flowing at the torch. As suggested above....it is always recommended to install a pressure guage right at the inlet to the plasma and monitor it while the torch is cutting or in the test flow mode. If the Powermax45 see's less than about 90 psi at the inlet...it will shut off the torch. When the torch shuts off....after postflow at the torch stops, the pressure at the inlet will rise and shut off any error indicator.

Jim Colt

only thing I noticed lately is when I turn the plasma cutter on it makes a high pitch electronic squeal/krackle, kinda like a CRT TV