Hello Guest it is August 20, 2019, 07:24:06 PM

Author Topic: help please. destruction next step.  (Read 4114 times)

0 Members and 1 Guest are viewing this topic.

help please. destruction next step.
« on: August 25, 2006, 10:51:23 PM »
probably a dumb question but here goes.  we have a dynacnc plasma router table.  we are just using plasma.  bobcad is our design program, sheetcam, and mach 3 runs our machine.  if we set a cut height at lets say .06 in sheetcam, when the g code starts running we can watch our z axis and it will zero out when torch touches metal and then go to pierce height and then pierce delay, but then start running and z will move to as high as .400 and never go lower.  we will let it run for a sec and then stop it to measure to see and it is way above .06.  thc is on while running.  now, we can go to sheetcam, put .180 as a cut height and load g code in mach, leave thc off and machine runs at .06.  we are cutting 1/8" steel.  what is the deal.  is this normal.  why will machine not run at desired cut height.  help please.  we have had nothing but problems from this machine.  next step is to throw machine off cliff ???  any help will be greatly appreciated.
thanks
Re: help please. destruction next step.
« Reply #1 on: August 26, 2006, 04:45:19 AM »
Hello,
Hope i'm not boring you with thisone, but could it probably be that the up/down signals are inverted and-or switched?
I'm not really shure about THC sequence, because i've no experience with it (but similar capacitive height control on laser machining), but this is what i think.
As long as your tHC-unit does not report stable arc with THC on signal, your height control is inactiv. If this signal goes active, THC is enabled. If your thc-signals are crossed, and the active state is inverted(input signals tab, 'active low' setting enabled or disabled), then your system might correctly detect sheet contact, but the control would do the opposite of what is needed.
Hope this helps...
Kris.
Logic takes you from A to B, imagination takes you anywhere
Re: help please. destruction next step.
« Reply #2 on: August 26, 2006, 07:54:05 AM »
That are you using for a THC ?
Fixing problems one post at a time ;)

www.newfangledsolutions.com
www.machsupport.com
Re: help please. destruction next step.
« Reply #3 on: August 26, 2006, 07:57:17 AM »
i am not sure.  it is a dynacnc machine.  how do i find out.
Re: help please. destruction next step.
« Reply #4 on: August 26, 2006, 07:58:35 AM »
Hello,
Hope i'm not boring you with thisone, but could it probably be that the up/down signals are inverted and-or switched?
I'm not really shure about THC sequence, because i've no experience with it (but similar capacitive height control on laser machining), but this is what i think.
As long as your tHC-unit does not report stable arc with THC on signal, your height control is inactiv. If this signal goes active, THC is enabled. If your thc-signals are crossed, and the active state is inverted(input signals tab, 'active low' setting enabled or disabled), then your system might correctly detect sheet contact, but the control would do the opposite of what is needed.
Hope this helps...
Kris.

how do i figure out  if this is switched.  it was working fine a week ago. 
Re: help please. destruction next step.
« Reply #5 on: August 28, 2006, 03:30:13 AM »
Hello,
If it was working fine a week ago, then the signals will probably not be mixed.
Did you change the computer or installed or upgraded to a new mach version or something?
are you using a breakout-board that's optically isolated?
If none of the above, i think there might be something wrong with the THC itself.
Can you contact it's maker?
Good luck,
Kris.
Logic takes you from A to B, imagination takes you anywhere
Re: help please. destruction next step.
« Reply #6 on: August 28, 2006, 07:05:45 AM »
that is what we were thinking also is the thc has a prob.  going to contact the maker today.  thanks for your response.  what is weird also is if we turn thc off, the torch still may not be exactly .06 off the material if that is what we set as a cut height.  i don't know if it is in mach3 or something else.  like i said, we have had numerous problems with this thing since we have owned it.  just trying to eliminate one thing at a time.
Re: help please. destruction next step.
« Reply #7 on: August 28, 2006, 07:18:02 AM »
Hello,
If you say you've had numerous problems with your THC, then there's also the possibility that you have grounding problems, or maybe some interfacing problems. maybe a voltage issue?
Kris.
Logic takes you from A to B, imagination takes you anywhere