Riddle/problem from a new guy

New to PlasmaSpider? Introduce yourself to the community and tell us a little about you.
Post Reply
Buckwild
1/2 Star Member
1/2 Star Member
Posts: 7
Joined: Sat Jan 11, 2025 2:22 pm
Location: TN

Riddle/problem from a new guy

Post by Buckwild »

Hey guys, I've only owned a plasma table for about 2 months now and I've basically learned everything I know about cnc plasma, sheetcam, and mach3 on this site. Cant tell ya how valuable its been. It seems every question that could possibly be asked, has been asked and answered on here, and can be found with a search, but I've got a problem I just cant figure out.

Im running a Premiere Plasma table, Hypertherm Powermax Sync 85, using sheetcam with the post processor from premiere, and mach 3. It has a floating head with machine torch and Proma THC. Once I stumbled through the learning curve, I have cut parts flawlessly for the last month.

This morning, I tried to cut one of the same parts (same file I've been using) and noticed the pierce height was incorrect. After watching the machine run, I turned off the plasma and ran the file over and over watching what was happening. The torch moves down to the plate and stops on its own without tripping the floating head limit switch, retracts to pierce height, (which is incorrect of course) and then starts the cut. Watching the digitize light on the diagnostics tab of mach3, it never comes on, so it is not somehow getting a false reading from the limit switch when the torch touches the plate.

The part I am cutting is a rectangle about 1.5" wide and 18" long with ten 1/4" holes ran all down the middle, so I stacked 3/8 thick pieces of wood like a stair case down the part from the second to the fourth hole. The torch will come down and touch the plate and stop on the first hole, proceed cutting motion, lift and travel to the second hole, come down and stop on the wood which is 3/8" higher now than the first hole, lift and proceed cutting motion, lift and travel to the third hole, another 3/8" higher, etc. then after running through the cutting motion on the last stack of wood (which is now 1.125" higher than the original place the torch started in it's Z axis), the torch will move to the next hole (where there is no wood) and of course move all the way down to make contact with the original plate, the torch stops when it makes contact with the metal, and proceeds with cutting motion. All of this is done without the limit switch being tripped, and the digitize light never coming on in Mach3.

The only way I can explain how it does this, is if Mach can see and abrupt change in amperage in the z axis motor, and know it needs to stop motion, but I didn't think Mach could do that, can it?? The other thing is...if it COULD actually do that, then I obviously just have some settings wrong that I would need to change...except for the fact that it doesn't always do it!!!! I probably ran this part with the torch off 40 times, and 90% of the time the torch stops moving down as soon as it comes in contact with something, but 10% of the time, it will actually make contact with whatever is below it, and continue moving down until the floating head limit switch is tripped, raise to the correct pierce height like it should.

My only explanation is I am hoping Mach can indeed see amperage changes and stop motion due to it. Being this particular motion is lowering a torch which is on a floating head, the load change in amperage would be extremely limited and hard to detect, therfore sometimes it would detect it and stop downward motion, and sometimes it wouldn't and therfore the limit switch would stop it. Well....I just had a thought, I can test that by holding the fixed frame on the motor shaft and take the floating head out of the equation....I'll do that now....

OK....scratch all that. Wish I would have thought of that before writing this all out, but whatever, maybe it will help with the diagnosis. Mach is not recognizing a change in amperage, I held some serious upward pressure on the z axis plate and it did not affect it.

My only other thought was maybe the limit switch was making continuity with the torch due to metal dust, and when the torch touched the plate it simulated the switch action, and maybe it did it so fast it never actuated the digitize light in Mach, but honestly I dont know if the switch is wired up as NO or NC, and I blew everything out with compressed air anyways, and it performed the same way on the wood, which would not have contact with the base metal, therfore I didn't investigate that any further.

Just to add to the confusion...when I just did the test of trying to hold the z axis plate, afterward, I ran the program twice and it correctly used the floating head switch 90% of the time. It didn't use the switch on only one hole each time I ran the part. If anyone has any input on this, please help, because I am beyond stumped!!
Thanks
Buck Adams
Buckwild Innovations
5x10 Premiere Plasma Table
Hypertherm Powermax 85 Sync machine torch
Hypertherm Powermax 45 hand torch
User avatar
djreiswig
4.5 Star Elite Contributing Member
4.5 Star Elite Contributing Member
Posts: 2049
Joined: Thu Nov 19, 2015 10:02 pm
Location: SE Nebraska

Re: Riddle/problem from a new guy

Post by djreiswig »

It sounds like your z switch is intermittently closing before the torch has touched the material.
Are you positive that the digitize input is where the switch is connected? My system uses Z home for this purpose.
Can you get the input to light by moving the torch up by hand and triggering the switch?
2014 Bulltear (StarLab) 4x8
C&CNC EtherCut
Mach3, SheetCam, Draftsight
Hypertherm PM65
Oxy/Acetylene Flame Torch
Pneumatic Plate Marker, Ohmic, 10 inch Rotary Chuck (in progress)
Buckwild
1/2 Star Member
1/2 Star Member
Posts: 7
Joined: Sat Jan 11, 2025 2:22 pm
Location: TN

Re: Riddle/problem from a new guy

Post by Buckwild »

Yessir, its wired to the digitizer, it illuminates when moving it by hand. It's also what I referenced back when I calibrated the switch offset. Plus, when I watch the diagnostic screen while the program is running with the torch off, the digitize light comes on every time the z axis works the way it is supposed to and you can audibly hear the limit switch click.
Buck Adams
Buckwild Innovations
5x10 Premiere Plasma Table
Hypertherm Powermax 85 Sync machine torch
Hypertherm Powermax 45 hand torch
adbuch
6 Star Elite Contributing Member
6 Star Elite Contributing Member
Posts: 10827
Joined: Thu Sep 21, 2017 5:22 pm
Location: Tucson, Arizona
Contact:

Re: Riddle/problem from a new guy

Post by adbuch »

As you suggest, perhaps there is some contamination, or perhaps an intermittent connection from the switch to your digitizer. Perhaps check out the connections to the switch and digitizer to make sure the wire is not loose maybe oxidized. I doubt this has anything to do with your torch current (amperage). Have you serviced the table lately? This would typically involve cleaning, testing wiring, mechanical parts, etc. Let us know what you find out.

David
Dirtmotor
3 Star Elite Contributing Member
3 Star Elite Contributing Member
Posts: 327
Joined: Wed Aug 24, 2022 2:48 pm

Re: Riddle/problem from a new guy

Post by Dirtmotor »

I have a premier table also , this may not be your problem ,but on mine when I have this problem it is uasualy the UC 100 adapter at the control box end . Most of the time I can wiggle it and it fixes the probem .
Buckwild
1/2 Star Member
1/2 Star Member
Posts: 7
Joined: Sat Jan 11, 2025 2:22 pm
Location: TN

Re: Riddle/problem from a new guy

Post by Buckwild »

Adbuch - Yessir I've cleaned all connections just grasping for answers, but I doubt it has anything to do with it because if it thought the limit switch made contact, it should lit the digitize light. If this was a "real" light bulb in a control panel, I would expect this as a possibility, because it would take some time to heat the filament before it was visible to the human eye, and it may be performing this "short circuit" so fast that the bulb does not have time to light up, but since it is just a fake light on a screen, I'm assuming it would be visible even as a flash because its just the program that turns it on. Whether the trigger sequence happened in time measured in seconds (working correctly) or in milliseconds (short circuit) the program would light the digitizer.

Dirtmotor - So you are saying that you have had this exact same problem? The torch somehow "knowing" when it touches down on an object? Even objects that do not conduct, like wood?
Buck Adams
Buckwild Innovations
5x10 Premiere Plasma Table
Hypertherm Powermax 85 Sync machine torch
Hypertherm Powermax 45 hand torch
Buckwild
1/2 Star Member
1/2 Star Member
Posts: 7
Joined: Sat Jan 11, 2025 2:22 pm
Location: TN

Re: Riddle/problem from a new guy

Post by Buckwild »

Dirt motor - The reason I asked the previous, is if I can clean that connector and it solves the problem, wonderful! But to be honest, I'm so intrigued on HOW it is doing this, I'm basically more invested on wanting to understand how this is happening than I am concerned with getting the table back in operation lol. If it only happened on metal, I would be chasing wires and connections everywhere to see where a chaff or dust buildup could be causing a intermittent short when the torch tip contacts the plate, but beings this happens on wood too.....mind blown.
Buck Adams
Buckwild Innovations
5x10 Premiere Plasma Table
Hypertherm Powermax 85 Sync machine torch
Hypertherm Powermax 45 hand torch
Dirtmotor
3 Star Elite Contributing Member
3 Star Elite Contributing Member
Posts: 327
Joined: Wed Aug 24, 2022 2:48 pm

Re: Riddle/problem from a new guy

Post by Dirtmotor »

Are you sure your THC is on and working ?
Dirtmotor
3 Star Elite Contributing Member
3 Star Elite Contributing Member
Posts: 327
Joined: Wed Aug 24, 2022 2:48 pm

Re: Riddle/problem from a new guy

Post by Dirtmotor »

Just tried three holes on three levels of 1x cedar , with thc off, torch does what you described .
Buckwild
1/2 Star Member
1/2 Star Member
Posts: 7
Joined: Sat Jan 11, 2025 2:22 pm
Location: TN

Re: Riddle/problem from a new guy

Post by Buckwild »

Yes THC is on and working.
OK, so all you did was cut your THC off, and now the machine knows how to "sense" the top of material without using the limit switch on the float head?? How is it doing that?
Buck Adams
Buckwild Innovations
5x10 Premiere Plasma Table
Hypertherm Powermax 85 Sync machine torch
Hypertherm Powermax 45 hand torch
Dirtmotor
3 Star Elite Contributing Member
3 Star Elite Contributing Member
Posts: 327
Joined: Wed Aug 24, 2022 2:48 pm

Re: Riddle/problem from a new guy

Post by Dirtmotor »

Sorry , I did not unhook the switch it is still calabrated per premiers video . I think thats the only way it can work . Torch touches down,trips limit then raises up to cut height .
Buckwild
1/2 Star Member
1/2 Star Member
Posts: 7
Joined: Sat Jan 11, 2025 2:22 pm
Location: TN

Re: Riddle/problem from a new guy

Post by Buckwild »

Right, if the limit switch is working, it will walk a flight of stairs and always retract to correct pierce height. WITHOUT the limit switch, it should not be able to do that, it would just try to bury the torch into any material that was higher than the original start point. I have no idea how the machine is sensing the top of the material.
Buck Adams
Buckwild Innovations
5x10 Premiere Plasma Table
Hypertherm Powermax 85 Sync machine torch
Hypertherm Powermax 45 hand torch
User avatar
acourtjester
6 Star Elite Contributing Member
6 Star Elite Contributing Member
Posts: 8430
Joined: Sat Jun 02, 2012 6:04 pm
Location: Pensacola, Fla

Re: Riddle/problem from a new guy

Post by acourtjester »

After reading part of your original post I would like to point out a few things. the THC and the floating head switch are 2 completely separate operation or functions. The floating head switch is only to find the metals surface (this is the same if you had an Ohmic sensor) some software will have a travel distance for each axis and this is part of the setup. The software will look at 2 different positioning methods (DROs) one is machine and the other is work positions. We normally use the work Coordinate when running a G-code, meaning we move to a start position and zero out the DROs.
The machine coordinates are setup when the table is homes (normally at the power up). Now some software have stored the travel limits for each axis. It seems your Z is seeing the down limit before the floating head touches the metal surface. Since you table was working you have seen this happen. It could be the setting for the bottom limit or travel distance has changed. The down limit is over ridding the floating head so it is not allowed to travel to the metal surface. The retract height shown in the DRO is just following the G-code to a height, but since the floating head did not find the metal that is now off. The digitize light is showing the Probe circuit and this is different from the floating head switch.
If you are using Mach a floating head switch will light the Z home light and if you have a Ohmic sensor it shows on the digitize light.
The G-code for these are different G28 for floating head and G31 is for digitize light.
The THC only comes into play after the pierce and the torch starts to move in the cutting operation. Nothing to do with the finding of the metal surface operation.
DIY 4X4 Plasma/Router Table
Hypertherm PM65 Machine Torch
Drag Knife and Scribe
Miller Mig welder
13" metal lathe
Small Mill
Everlast PowerTig 255 EXT
Buckwild
1/2 Star Member
1/2 Star Member
Posts: 7
Joined: Sat Jan 11, 2025 2:22 pm
Location: TN

Re: Riddle/problem from a new guy

Post by Buckwild »

acourtjester, Yessir I understand the THC is not related to the floating head switch, sorry I'm not sure what I said that might have suggested that, but Im glad you mentioned ohmic sensing. I should have stated this in the very beginning to describe what is going on because its the perfect description...the machine acts like it has an ohmic sensor that will pick up ANYTHING, even non conducting wood. It has never stopped short of the material, as you described with the down limit being reached. It always makes it down and contacts the material, no matter how far away or how close the material is. As I mentioned, it will stair step up a stack of wood, then at the end of the stairs, plunge all the way back down to the original plate, making contact with the material every time. As for the digitize or probe light, the limit switch for the floating head is wired to light the digitize light. The calibration video from the manufacture specifically shows using the digitize light in mach to see the distance traveled to set the switch offset distance in the post processor. Is this something I should change, or better to just leave it alone? I would assume if the post processor is coded correctly then it wouldn't matter...but then again I have this crazy problem on my hands. Its ran perfect until now though. I did reach out to the manufacturer and he tried to help but he needs to log into my computer and I dont have internet out in that shop, so I'm going to run an ethernet or get a signal booster or something and then contact him again when I have internet out there.
Buck Adams
Buckwild Innovations
5x10 Premiere Plasma Table
Hypertherm Powermax 85 Sync machine torch
Hypertherm Powermax 45 hand torch
User avatar
djreiswig
4.5 Star Elite Contributing Member
4.5 Star Elite Contributing Member
Posts: 2049
Joined: Thu Nov 19, 2015 10:02 pm
Location: SE Nebraska

Re: Riddle/problem from a new guy

Post by djreiswig »

Can you use your phone as a hotspot to get WiFi to your shop?
2014 Bulltear (StarLab) 4x8
C&CNC EtherCut
Mach3, SheetCam, Draftsight
Hypertherm PM65
Oxy/Acetylene Flame Torch
Pneumatic Plate Marker, Ohmic, 10 inch Rotary Chuck (in progress)
User avatar
acourtjester
6 Star Elite Contributing Member
6 Star Elite Contributing Member
Posts: 8430
Joined: Sat Jun 02, 2012 6:04 pm
Location: Pensacola, Fla

Re: Riddle/problem from a new guy

Post by acourtjester »

I had a similar problem with the internet in the shop. I got a 50' cable and put my wifi modem in a window closer to my shop and them helped.
As I stated if you are using a floating head switch that used a homing command G28 and Z as the axis. The offset is for the dead space of the switch action (mechanical switch) between when in trip and when it releases (upward motion). This can be a few thousands and is in the G-code for correction the position for the pierce height. this should be wired to the Z home input. If you use a ohmic sensor it is G31 Z axis and is wired to the Probe input (digitizer light on the diagnostic page) when tripped. video shows a floating head operation, the torch hits a Z moves slightly more before retracting.
Z home.JPG
new torch holder AA.jpg
new torch holder AA.jpg (90.98 KiB) Viewed 800 times
new torch holder AA.jpg
new torch holder AA.jpg (90.98 KiB) Viewed 800 times
Here are 2 G-codes on with a g28 and the other a g31
g28 action.JPG
g 31 action.JPG
DIY 4X4 Plasma/Router Table
Hypertherm PM65 Machine Torch
Drag Knife and Scribe
Miller Mig welder
13" metal lathe
Small Mill
Everlast PowerTig 255 EXT
Post Reply

Return to “Introduce Yourself”