[virx1]

Greetings from Estonia, and I'm sorry in poor English language.

Building a new CNC Plasma. YouTube is a video where the torch goes against the material, and then rises up and will arson.
Home built CNC plasma table Mach3 - YouTube
How can this be done or what the program can do it.
Can this be done without electronic height adjustments (THC)? I do not believe that all self-builders have have bought it at the beginning.
Can anyone give a hint where this disscussed. There is still one problem. where I restart computer then engine will not start. Settings pin and port fain and led in my controller work rightly. I use Vista and Mach3.

Please help.

[urbnsr]

Hello virx1,

Not a stupid question. Search the internet for a "floating torch head". The link below is one of the many results from that search. Basically you need a linear slide of some kind and a switch that will tell Mach3 that the torch has touched the top of the metal.


http://www.cnczone.com/forums/plasma...orch_head.html

HTH
Paul

[LeeWay]

Right. Mach 3 handles it okay. I use a CandCNC THC control on mine and it handles it as well.
Here is a video of how mine was setup. It was new then, so the cutting was not dialed in correctly, but it might better illustrate how the switch works.

Plasma cutter with Die Grinder scribe - YouTube

[virx1]

Greetings to all.
Thanks for the hints.
I have researched the Internet 1.5 days, and I have become aware that an error has
My G-code. G20.1 is a particular need to add a value of the Z axis.
Lazycam do not do it just puts G28.1 (Probe for stock) and nothing happens. If, for example, put G28.1 Z52 (Probe for Stock) will employ the command line, and Z homeswiths applied. The error can be Lazycami program or what. Add an image to your Z switch Attachment 213428

[LeeWay]

I'm not sure what you are asking, but this may help.
I use Sheetcam exclusively on the plasma. I use it for other machines too, but that is all I use on plasma.
It has a Z switch offset setting in it. What it is is the distance it travels back up once the switch is tripped to get back to the top of the plate.

Mine is something like .48" I think. Every machine will vary, but the plate thickness doesn't matter. Once back at the top of the plate, the Gcode will add pierce height and then go to cutting height.

That floating head switch is the only switch I have on the Z axis.

[virx1]

Hello

Ordered a new Proma THC controller. When the torch goes out then the the voltage for a while, to controller and Mach3 adjusts the height.
Does anyone have a problem with that?
Another problem is that the cuts crookedly. which could be the cause?

[virx1]

[LeeWay]

Crooked cuts could be any number of things. Cutting volts, amps set on machine, air quality, cut height, total plate piercing initially, speed to fast, consumable condition etc.
I don't cut thick plate yet, but do tend to see beveled edges occasionally. Generally replacing the consumables fixes that issue for me.

I never get that kind of severe bevel though.

[virx1]

how fast and what amp you are cutting 3mm iron. ja Do you can see what you are cutting volts ?

[urbnsr]

Yes - All the above. If you believe everything else is right, I would slow down the feed quite a bit while running at the proper amperage for the material thickness to see if that helps. Consider your ground connection, also. You may get slow-speed dross after slowing down, but if the cut is better, you can speed it up from there. Slow-speed dross and no improvement would lead me to believe I have another problem.

On the Proma THC: Do you mean that after the torch is commanded off, that there is voltage leaking down and the Proma is trying to move the torch height to compensate? If so, and I don't know Mach3, but there should be a config setting that "freezes" the torch height if there is no ARC-OK signal. Torch goes out - ARC-OK signal goes down - Mach3 should see this and not accept Proma commands.

HTH
Paul

[LeeWay]

I cut 304 3mm stainless steel at 75 IPM which translates to about 1500 mm/min. I use 85 to 90 volts on the THC. Pierce height is .1" or 2.5mm and cut height is one 5th of that.

I am using PM30 consumables on a Hypertherm PM45 machine.

I use basically the same settings for mild steel, but speed it up a little bit. Maybe 80 IPM.

The volts are in the THC package and may differ with different brands of cutters and THC's. The THC I have uses the volts to regulate the cut height.

[virx1]

If I turn off the torch then the ARC OK signal will lasts until the fall 20v
Mach3 thinks that the torch burns, although I'm turned off thorch.
Do you disappears immediately voltage in the thc controller if you are turned off the torch?

[LeeWay]

My Arc okay and torch quits at the same time. That is when the Gcode calls for M5.

[urbnsr]

OK - I think your setup is getting it's ARC-OK signal from the Proma? I have my ARC-OK coming direct from the cutter and that signal will drop as soon (or very quickly after) the torch is turned off. My Proma's voltage reading does take some time while the voltage is bled off after the torch is turned off. Can you wire the ARC-OK signal direct from the cutter?

[urbnsr]

Also - The axis velocity might be able to be used to accept input from the THC. With LinuxCNC, I can program of minimum actual velocity, say 80%, of programmed velocity as a threshold. If the the machine's velocity slows down below 80% (like when programmed for cutting a smaller hole), LinuxCNC will ignore input from the Proma until the velocity returns to a speed greater than 80%.

I think the Proma's ARC-OK signal is sort of a pseudo signal based on measured voltage. Not 100% sure about that as I haven't used it.

[virx1]

It is a good idea. I have somehow take signal arc ok in torch relay.
if the arc ok is not active whether THC stops working?

[Torchhead]

Arc OK should not be based on voltage. It senses CURRENT (Amps) and shuts off instantly as soon as the arc stops. Your plasma does not have an ARC OK signal so you need to rig up something the measures the CURRENT on the work clamp. Either that or a Current Transformer in the AC side of the plasma to sense AC current IN. Either method works. MACH3 is not supposed to keep the THC logic enabled if the torch ON signal goes away. While the external THC may send signals MACH3 should ignore them and refuse to move the Z unless it gets a move commend from G-Code.

[virx1]

This arc ok I'll have to look into the inside of the plasma cutter maybe I can take a signal from somewhere.
Today I tried to do a test to find the cutting speed and amps.
What might be wrong? Cutting the x-axis is cut straight but the y axis is tilted right side.
Can anybody give adviceAttachment 224438

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[urbnsr]

My first look would be at the torch tip - Is the hole worn in a way to consistantly give you those results? If the torch was not plumb, both Y-axis "walls" would be angled. If it was a torch height issue, the X-axis would also look similar. Can you reverse the cut path direction and would that flip-flop the angled portion?

ARC-OK signal - What cutter do you have? Your earlier comment about torch relay, might you want to break the ARC-OK signal with that relay? That might work, but you should not have to do that.

[virx1]

I changed the tip torches still the same.
It does not matter whether you cut from the top down or the bottom up. y axis is always tilted right side. The left edge almost straight. x axis cutting the sides practically parallel to the line. I am happy with the x axis. the y axis is the headache. Did you cut both axes identically?
the machines are:
S-PLASMA 85CNC 2079