Plasma machine problem

Hi,

I have a CNC plasma machine that I was very happy with but now I have a problem with it.
Plasma source: Hypertherm Powermax 45xp
Torch: T45m
Control: XPTHC-4H
Software: NcEditor v12 from Weihong
CNC table: downdraft, Chinese made.

PROBLEM:
Normally when I run a program the cutting head makes the IHS (touches the metal sheet and sets the cutting height)
But now the cutting head goes down, touches the metal sheet and tries to keep going down, not sensing the metal sheet.
This problem is not permanent. Sometimes it works.

I have changed the consumables SHIELD, Cutting head, Electrode, Gas ring. (everything is from my local Hypertherm distributor)
My local Hypertherm distributor said that T45m torch is an old torch for Hypertherm powermax 45.
I tried to contact the Chinese manufacturer but they first said I should change the consumable (what I already did) and then they said they don't understand the problem etc.

Can anyone give me a hint what to try and do?

Thanks Dan

>>>>But now the cutting head goes down, touches the metal sheet and tries to keep going down, not sensing the metal sheet.
This problem is not permanent. Sometimes it works.

Your machine likely has a SWITCH somewhere that is failing to detect when it touches the metal. Some machines have the torch on a slide, and on the slide is a switch. When the machine moves down, it touches metal, then the slide moves up and triggers the switch.

It's also possible that they designed the machine so the torch head itself acts as a switch when the copper head touches the steel. Not the best setup, but If this is the case, you need really clean metal and torch tip for it to work.

If you find an actual dry contact switch somewhere, it could be the contacts have eroded enough to no longer be reliable. I've seen this with practically every style of switch used. Test the switch for reliability.

Lastly, they may have used some sort of non-contact proximity switch. Just because an LED light comes on indicating a switched state does not mean the switched status has been recognized by the controller. In this case you need to follow the trigger wire back to the control and make sure it is tripping correctly. Most controls will have a dialog window to display when an input is activated or not, so check that.

If either dry contact or non-contact switch methods do make it to the control, you will need to dig thru your control settings to make sure nothing has changed in the software.

Thank you very much for the help. I will check the machine today. Have a great day!

Hi,

I am sorry for my late update.
I found a way to make it work for now but I should repair it.
I found out I have a proximity sensor with a floating head.
I am not sure if the sensor is broken or the control unit.
What I do for now is:
1. I turn on the machine (everything)
2. I do my IHS,
3. it fails,
4. then I unplug the sensor from my control box,
5. the control box shows a E5 Error (collision error)
6. I plug the sensor back in
7. I manual cancel the error
8. I do IHS
9. it works, I can normally use the machine, sometimes it stops and I repeat the process

If I turn off the machine and start it back again I need to repeat the process.
I need to find out witch one is broken. The control box is very easy to replace but is more expensive than the sensor. The sensor is a pain in the back to take it out.
I so far checked the voltages with a multi-meter and everything seams OK

If anybody has any advice please let me know.

Thank you a lot!