Having a problem with our plasmacam

[oldetown]

I have a plasmacam and it gets quite a bit of use and we haven't had
too many problems up until now. A little while ago the machine
started acting funny and the torch height didn't stay consistant and
our cut quality suffered along with consumable life, we were running
Lincoln power sources. I called Plasmacam with my problem and they
asked a lot of questions with settings in the software, grounding,
machine and grate conditions. We verified all settings, had an
industrial electrician check and verify power coming in and table
grounding, we took the plasmacam all apart and cleaned it very
throughly (and checked for worn parts and z axis motor), and finally
bought another set of grates. The problem didn't seem to get fixed
and we kept on cutting and just kind of figured maybe our Lincoln had
had it. We went down to Eastec and talked with Hypertherm and ended
up with a Powermax 1000 for that machine. Had it wired up, grounded,
switched over to finecut consumables, read all the post on the forums
for hints in cut heights and arc voltage (along with the manual from
Hypertherm!), and started cutting. Our current problem is we are
cutting roughly .250 squares in a sheet metal part and we select
anywhere from 6 to 30 of these to cut at a time and it will cut a few
and then move to the next cut posistion and the torch won't fire but
the table still moves, then it will go along cut a couple, miss a
couple. I talked to hypertherm they didn't believe it was their
machine, and I have to agree with them because of the problems we
were having with our Lincoln power source. I forgot to mention our
pierce height is .100 and cut height is .077 and arc shift is .65 on
18 gauge CR. So if anybody has any ideas that would be greatly
appreciated.

[rcracer]

Sounds like you have all of the electro-mechanical stuff covered pretty well. The only other thing that I could think of that would affect both the Lincoln and the Hypertherm is the air supply. How dry is your air? Do you have sufficient volumn?
I have a DHC Plasmacam with a Hypertherm Powermax 1000 and when I have problems, it's usually a ground or my UPS. I have my Computer, monitor, pcam controller on a UPS with power filters on a seperate circuit. Sometimes the UPS needs to be cycled or I get some wierd symptoms. Time to get a better UPS

[samakthachai]

How much prices of plasma cam? what table?

[Allen123]

ok, I know what you are talking about. I have having the same problem. I can't get the height control to work right. I know arc volt setting and things like that, and have gone through and made many adjustments but still I can't get a consistan cut with out the tourch moving up and cutting air?

So you think it is the UPS ?

[rcracer]

Originally Posted by Allen123 ok, I know what you are talking about. I have having the same problem. I can't get the height control to work right. I know arc volt setting and things like that, and have gone through and made many adjustments but still I can't get a consistant cut with out the tourch moving up and cutting air? So you think it is the UPS ?

Assuming that you have all of your settings correct and your nozzle / torch are clear and in good condition, then in my opinion the biggest culprit of DHC problems is poor wiring and grounds.
My setup is as follows:
I have a 120v line that feeds the UPS ( CPU, PCAM controller, monitor ), a 220v line to the Hypertherm Pmax 1000. The Hypertherm work clamp is clipped to the Plasmacam frame. I also have a heavy cable that I clamp to the frame work piece. I never trust the work to have good continuity to the grates. The frame is grounded to it's own ground rod just outside the shop less than 10 ft away.
Other than a couple of times were I had entered an bad number in the setup ( ie. moved a decimal place in material thickness ), the DHC lost control mainly because the additional ground cable was not making good conatct with the work. The times that I lost communications to the torch, the UPS was acting up. ( I suspect the UPS is marginal in capacity ).
When I have a good ground, a correct setup and good consumables, I can cut 16ga. forever and the DHC follows the warps perfectly.
The bottom line is that, electrically, the Plasmacam needs to have good wiring, a clean power source and ground integrity. That sensitivity along with the parallel port requirement is my only complaint with the system. Otherwise it does exactly what I tell it to do and it serves me well.

[Allen123]

Grounding is what you think it is. Humm, I guess I can check that out. I am not sure if there is a cable comming off the machine that is grounded. Also when we set up the hyper it is connected right to the material.

You are saying to connect it to the table first then go from the table to the matrial.

Also to run a ground cable from the machine's let say leg of the table out to a gournd in the building or in the ground itself?

I know this is an electrical setup and needs to " flow" right and you make it sound like these are simple things to fix. Isn't there some way to see that the machine is not grounded right?

It's just been a real mess, I know the settings need to be dialed in and test runs will get me there. So I get that.

It's just when the height sensor doesn't seem to be working right whent he tool touches off starts to burn then goes up in the air way off the work piece and continues to cut...

So the ground setup and power in on the controller and on the hyper therm.

Is there anything else that I could be missing.

1 settings in the software for the voltage Z shift and so on.

2 Machine ground, material ground and special gold cables to make sure no feedback.

3 Wire the controller to a UPS on a differnt ciurcuit then the hypertherm

4? Anything else that I could be missing.


It's not the Air becuase we are running gas with 3 filters. The settings we have worked back and forth and those I can work with more.

Check the gound and wire setup Ok I think I got it. If you can think of anything else let me know.

Thanks for the help.

[rcracer]

Originally Posted by Allen123 Also to run a ground cable from the machine's let say leg of the table out to a gournd in the building or in the ground itself?

If you look at the Plasmacam manual on page 4-10, there is a diagram that shows the electrical configuration and grouding recommended.
They also recommend that the work clamp be connected to the grate and the grate to a good EARTH ground. They also say that the earth ground should not be closely tied to the ground for the circuit supplying the computer and the controller.

Not only is the above important for electrical integrity and operational integrity, it is for safety. If the circuit electrical ground were to fail. the earth ground will provide a safe path.

[Alex S.A]

I got a likely problem using Hypertherm machine. It didn't start the arc between two part. I meant to say the torch cut one part and then when try to start a new part it doesn't start the arc. The problem was solved when I increased the time at CNC for start arc. Increase this time to above 6 seconds and then you 'll get the arc. I am taking in consideration that the program is okay.
Alex S.A

[Allen123]

We the more I work with the machine the better it gets. After a few setting watching and stuff I have got the machine working well. Every once in awhile some stuff gets stuck on the plasma head and I need to clean it out and then the machine runs fine.

Have not ground the machine yet, but we are building a room for the machine to suck all the air out.

I will keep you posted on progress.

[BIGCNC]

Sounds like electrical noise problem you might have check the servo cable sheilding with a ohm meter and make shure your ground passes a light bulb test .

[alliance_metal]

sounds like your DHC/Z-axis is a little loose. might want to tighten up those screws...design flaw imho... ..especially if you've had collisions.

also when it comes to piercing, I pierce @ .16x and cut @ .13x ..always think of it as "stabbing" the material... that way you don't get as much blowback into your nozzle.