Torch raises during cuts. FRUSTRATING

CandCNC plasma table components discussion forum
Post Reply
ajk2004
1.5 Star Member
1.5 Star Member
Posts: 42
Joined: Sun Jan 24, 2016 2:22 pm

Torch raises during cuts. FRUSTRATING

Post by ajk2004 »

Hey guys,
I've had a c and cnc system for about 3-4 years. I am running mach3 and sheetcam. I have a weird problem that has been happening ever since I got the machine up and running. I know the problem will happen so I have to babysit the machine knowing not if it will happen but when. Randomly during cuts (usually during long cuts) the torch will start to raise off of the metal. The down light is on, meaning the system is trying to lower the torch, but it keeps raising. I quickly kill the cut. Otherwise it will screw up the piece. I have to then go to the previous M05, restart the cut, turn torch off until I get to the spot where I stopped it and manually turn the torch back on. Does anyone know how to fix this or what is going on? Thanks
Andy
whiskeymike
3 Star Member
3 Star Member
Posts: 345
Joined: Mon Feb 23, 2015 5:23 pm
Location: Austin, TX

Re: Torch raises during cuts. FRUSTRATING

Post by whiskeymike »

Sorry, I don't have an idea for you. That seems really odd. I run Mach3 and sheetcam and don't experience it. Do the volts jump/drop at that point? Is the cut on top of/adjacent to another cut line? When it happens, does the arc break and the torch go out, or does it come back down, but boogers up the piece?

The fact that you rewind and replay and it doesn't repeat is really odd. I was wondering if you had rules on speed (like lower speed if corner is steeper than x). How often does it happen? Out of 10 or a 100 pieces, how many times? Have you turned off rules? If it's frequent, what happens if you turn off torch height control? What kind of table/gantry do you have?
User avatar
djreiswig
4.5 Star Elite Contributing Member
4.5 Star Elite Contributing Member
Posts: 1929
Joined: Thu Nov 19, 2015 10:02 pm
Location: SE Nebraska

Re: Torch raises during cuts. FRUSTRATING

Post by djreiswig »

Is your work clamp connected directly to the material?
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
WyoGreen
4 Star Member
4 Star Member
Posts: 897
Joined: Tue Mar 04, 2014 8:36 pm
Location: Cheyenne, Wyoming

Re: Torch raises during cuts. FRUSTRATING

Post by WyoGreen »

I'm guessing that this is a Mach3 system. So Mach3 is telling the torch to lower, but this is a CandCNC system, so the torch raising and lowering is under control of the DTHC system. So what is the voltage display showing while the torch is raising? If you are cutting a thicker piece of material that doesn't warp, you could try turning off the DTHC and see what happens then.

That's all I have for now, Steve
Precision Plasma gantry
CommandCNC Linux controller w/Feather Touch & PN200 hand controller
HT-45 plasma cutter
Plate Marker
Router
Laser
robertspark
4.5 Star Elite Contributing Member
4.5 Star Elite Contributing Member
Posts: 1806
Joined: Mon Jun 12, 2017 6:43 pm

Re: Torch raises during cuts. FRUSTRATING

Post by robertspark »

what version of mach3 are you running?

can you post your mach3 profile?
User avatar
SeanP
4 Star Member
4 Star Member
Posts: 950
Joined: Thu Aug 01, 2013 11:50 am
Location: Co Kerry, Ireland

Re: Torch raises during cuts. FRUSTRATING

Post by SeanP »

Try lowering thc rate in mach, I think it's in relation to your z motor settings, default is 30, I'm down to 12 on mine, seems to be a good balance between thick a d thin on mine.
Powermax XP45
Home built table, Candcnc DTHC 2, Dragoncut 620-4
R-Tech 210 Tig, Jasic 250 mig
Sheetcam, Scanything, Coreldraw
Table build gallery
tcaudle
4 Star Elite Contributing Member
4 Star Elite Contributing Member
Posts: 1353
Joined: Tue Feb 28, 2012 6:47 pm

Re: Torch raises during cuts. FRUSTRATING

Post by tcaudle »

ajk2004 wrote: Fri Aug 30, 2019 12:24 pm Hey guys,
I've had a c and cnc system for about 3-4 years. I am running mach3 and sheetcam. I have a weird problem that has been happening ever since I got the machine up and running. I know the problem will happen so I have to babysit the machine knowing not if it will happen but when. Randomly during cuts (usually during long cuts) the torch will start to raise off of the metal. The down light is on, meaning the system is trying to lower the torch, but it keeps raising. I quickly kill the cut. Otherwise it will screw up the piece. I have to then go to the previous M05, restart the cut, turn torch off until I get to the spot where I stopped it and manually turn the torch back on. Does anyone know how to fix this or what is going on? Thanks
Andy
If the down indicator is ON in MACH then its MACH that moving it the wrong way or the motor tuning is such its stalling th emotor and making it move the wrong way. All the THC can do is "suggest" to MACH to jog the motor a certain direction . YOu need to confirm that when you jog the Z the readout increases and taht if you fast jog back and forth it never misses going the right direction . The DTHC has a seperaate feedrate speed and direction setting . Once it takes over the Z it uses ITS setting to control the speed/diraction etc. On DTHC IV machines the THC rate means nothing
Post Reply

Return to “CandCNC Forum”