Getting Frustrated....Torch hitting material

[65coop]

I'm completely new to this however.. I have been able to cut some parts out, so this isn't the first time I've cut with it..

I have a Premier Plasma 4x4 table, w/ water table. with a Hypertherm 45xp w/ machine torch. and a Proma THC
The software I'm using is MACH3 / SheetCam

This started recently and nothing I do seems to help...

I load my g code (a tap file that I have used in the past with no issues), zero my machine and "start cycle", it cuts great for a few inches and then the torch starts dropping getting closer to the material and after a few inches it hits. I stop the machine and raise the torch.

I hit "go to zero" on MACH3, it moves to the zero location and proceeds to drop the torch 5.23" past what I just set at zero on the plate.....

So far I have:
Calibrated the floating head (per Premier Plasma video) ** several times
Adjusted the THC (per Premier Plasma video) ** several times
Cleaned the ground
changed out the consumables

I have NO idea what it could be..... Like I said, I'm new to this, but I do know enough to look at the g code to see if something is in there for Z to move down - nothing..

Why is drops 5.23" when I zero it to a location that I previously set, is way beyond my knowledge...

And why the torch gradually starts getting closer to the material as it cuts?

hopefully... it something simple, as I mentioned.. it has worked very well previously..

Help...?

[adbuch]

Does your machine cut fine if you disable the thc and manually set the cut height?
David

[weldguy]

Ya, i'm with David, sounds like your THC system is telling the torch to get lower. Disable it and do a simple straight line cut manually setting the torch .060" off the plate and see if you are successful. If so, turn the THC back on and if the torch drops again you know what it is. At that point try increasing your arc voltage 10v at a time with each test cut and at some point the torch should stay off the material and you can dial in the THC votage from there to achieve the desired .060" cut height with THC on. Here are some THC tips from Hypertherm viewtopic.php?f=202&t=30526

[65coop]

Last night, as I was shutting everything down, I noticed a button in the MACH3 screen for the THC, I clicked it and it lit up green?
I may have been cutting without it on? or is the green to show off?

I'll fire it up again later today and see. I'll try it both ways and respond.

Thanks guys!

[adbuch]

Last night, as I was shutting everything down, I noticed a button in the MACH3 screen for the THC, I clicked it and it lit up green?
I may have been cutting without it on? or is the green to show off?

I'll fire it up again later today and see. I'll try it both ways and respond.

Thanks guys!

That would probably do it. May have been an easy fix.
David

[65coop]

Well.. I tried the THC button in MACH3. It went to the pierce start, and stayed there... I switched it back and it did follow the cut, but didn't cut.

I decided to scuff a really clean spot on the material and reconnect my ground (I use twist lock style ground) -- AND IT CUT WITHOUT DROPPING....
Probably cleaner than it has in a while..

I'm assuming it was the ground the whole time?

Now... What does the THC button on the MACH3 screen do? Would the ground keep the torch from moving with the THC on?

[robertspark]

it waits for the arcok / transfer signal from the plasma cutter (some plasma cutters provide a signal, some do not) OR from the torch height controller.

what plasma cutter do you have?

what torch height controller do you have?

[adbuch]

It helps to read the entire post.
"I have a Premier Plasma 4x4 table, w/ water table. with a Hypertherm 45xp w/ machine torch. and a Proma THC
The software I'm using is MACH3 / SheetCam"
David

[robertspark]

It helps to read the entire post.
"I have a Premier Plasma 4x4 table, w/ water table. with a Hypertherm 45xp w/ machine torch. and a Proma THC
The software I'm using is MACH3 / SheetCam"
David

Can't be bothered, too verbose. Time is short, you obviously have more time, thanks for extrapolating the info

To the OP, which proma THC do you have?
there are two, a Proma THC150 and a Proma SD
The proma SD is a self contained (Step & Direction) Z-axis control
https://www.proma-elektronika.com/compa ... generator/

the proma 150 provides a UP and DN and ARCOK signal back to your motion controller.
https://www.proma-elektronika.com/compact-thc-150/

So, depending upon which THC variant you have you could have two sources of ARCOK / transfer signal available. Taking the signal from the hypertherm would be better than from the Proma 150 if you have that variant.

If you have the Proma SD then it will do whatever it wants to do without any means for you to control it (unless you do other things circuit wise as an additional circuit [there are posts on plasmaspider where others have tried various things if you search for them]

Your "go to zero" is a problem with using THC (it cannot be fixed!) because of the way THC works within Mach3 or with the Proma SD / Proma 150
The proma SD will move the Z axis with no feedback to mach3 as to where it has moved
the proma 150 with THCUP and THCDN output controls the z-axis as an (sort of) "out of bounds" axis (i.e. its position is not tracked and it just shunts the z-axis up and down) so you cannot use "go to zero" you have to re-zero / home the axis again (either via G31 + G92 Zxxx to set a temporary offset for the Z OR via G28 Zxxx to rehome the zaxis) ..... that is why the torch is re-zero'd before refiring the torch at the start of the next cut.

[adbuch]

Can't be bothered, too verbose. Time is short, you obviously have more time, thanks for extrapolating the info

I've got a J.O.B. But still have time to read the complete post. I find it helps to know all the facts in order to make informed decisions.
David

[robertspark]

Can't be bothered, too verbose. Time is short, you obviously have more time, thanks for extrapolating the info

I've got a J.O.B. But still have time to read the complete post. I find it helps to know all the facts in order to make informed decisions.
David

keep up the good work

[65coop]

To the OP, which proma THC do you have?
there are two, a Proma THC150 and a Proma SD
The proma SD is a self contained (Step & Direction) Z-axis control
https://www.proma-elektronika.com/compa ... generator/

the proma 150 provides a UP and DN and ARCOK signal back to your motion controller.
https://www.proma-elektronika.com/compact-thc-150/

So, depending upon which THC variant you have you could have two sources of ARCOK / transfer signal available. Taking the signal from the hypertherm would be better than from the Proma 150 if you have that variant.

If you have the Proma SD then it will do whatever it wants to do without any means for you to control it (unless you do other things circuit wise as an additional circuit [there are posts on plasmaspider where others have tried various things if you search for them]

Your "go to zero" is a problem with using THC (it cannot be fixed!) because of the way THC works within Mach3 or with the Proma SD / Proma 150
The proma SD will move the Z axis with no feedback to mach3 as to where it has moved
the proma 150 with THCUP and THCDN output controls the z-axis as an (sort of) "out of bounds" axis (i.e. its position is not tracked and it just shunts the z-axis up and down) so you cannot use "go to zero" you have to re-zero / home the axis again (either via G31 + G92 Zxxx to set a temporary offset for the Z OR via G28 Zxxx to rehome the zaxis) ..... that is why the torch is re-zero'd before refiring the torch at the start of the next cut.

I have the Proma SD

So I assume the "THC" button in MACH3 is useless?

I did cut several parts last night, probably the best cuts and no issues I've done since I bought this setup a little over a year ago! I feel pretty dumb now that I figured out it was the ground all this time.....

[robertspark]

yes the thc button in mach3 is of no purpose with the proma SD as it is a self contained THC

[adbuch]

I did cut several parts last night, probably the best cuts and no issues I've done since I bought this setup a little over a year ago! I feel pretty dumb now that I figured out it was the ground all this time.....

That's good news! Glad to hear you've got it going. Maybe share some photos of the parts you are cutting.
David

[65coop]

Thank you all for your support! As I mentioned, plasma is cutting great again..... But now I have an issue with my compressor....

I was sandblasting over the weekend and apparently it got hot in the compressor shed (Texas), so the thermal overload switch on the motor tripped. I let it cool, but the switch is not resetting...... Now I'm on the hunt for a Klixon thermal switch... and a cooling fan for the shed.

Regardless, the Plasma is sorted and I now know there is no use for the THC button in MACH3 LOL

Thank again guys!

[Larry83301]

Not sure which switch you have, but here's some
https://www.google.com/search?q=Klixon+ ... e&ie=UTF-8


Larry

[65coop]

Thanks for the link Larry! I ended up pulling it off the compressor, to find the actual PN.
When I had it in my hand, I was able to reset it, it took a lot more pressure than I was applying while it was on the motor. Works great now!

[65coop]

I do have one more slight issue that I could use some input on..

I've been cutting 12g material and just switch to some 10g, to cut some gussets for a project. The material was setup correctly in my SheetCam with no breaks in the lines, but when I cut, the cuts don't complete - its leaving 2mm from completely cutting the shapes out.
I assume this would be a setting on the THC? I also have a slight bevel and slightly jagged. Could this also be a setting in the THC?

Seems like i had the problem before and adjusting the voltage helped?