Mach 3 and Sheetcam THC on/off Rules

Mach3 and Mach4 questions, tips and topics can be posted here
Post Reply
TrinityFabworks
2.5 Star Member
2.5 Star Member
Posts: 186
Joined: Tue Apr 17, 2018 2:36 pm

Mach 3 and Sheetcam THC on/off Rules

Post by TrinityFabworks »

I am trying to edit my post processor in sheetcam to turn on or off the thc depending on different things like tight corners, small shapes, etc. I know how to set it all up in sheetcam. I need an M command (I think) for mach 3 that turns the THC on and off. My post processor gives M666 and M667 as suggestions of THC on and off, but I've read other posts that suggest that its not possible. Any suggestions appreciated.
AdrianH
2 Star Member
2 Star Member
Posts: 87
Joined: Tue Dec 27, 2016 1:08 pm

Re: Mach 3 and Sheetcam THC on/off Rules

Post by AdrianH »

Sorry of I get it wrong about what you are asking,

I assume this is the mach3 THC with scriber post? If you make the two macros up and place them in the C:/Mach3/macros/Pasma location, if I read correctly
M666.m1s is StartTHC()
M667.m1s is EndTHC()
Then apart from changing the variables in the post to suite your machine, that is all one would do to to the post processor.
The cut rules are generated and saved in Sheetcam and become part of the plasma cutting tools.

In Sheetcam go to "Tools" section left hand side and click on the create new code snippet
Name 'THC ON'
In the text box add:-
M666 (THC On)

and save.
Repeat again for another code snippet
Name 'THC OFF'
In the box M667 (THC Off) and save.

Next open the cutting rules editor and start to generate your cut rules, the two new code snippets you have just entered can now be part of your cut rules as in the start code and end code.

So you can build up a selection of cut ting rules that you are likly to need, when it comes tp actually cutting metal you can select what cut rules should be in use or not before generating the Gcode.

I hope that helps, sorry if I picked up the wrong idea let me know.

Adrian
TrinityFabworks
2.5 Star Member
2.5 Star Member
Posts: 186
Joined: Tue Apr 17, 2018 2:36 pm

Re: Mach 3 and Sheetcam THC on/off Rules

Post by TrinityFabworks »

Hey, thanks for the reply! I know how to set up sheetcam for cut rules, but I'm not sure if the m commands are correct for mach 3 thc on and off. How do I find this out? I've read that you have to have a macro for mach to turn it on and off but then there are glitches. Is there really no m command that turns the thc on or off in mach that can be created in the post?
AdrianH
2 Star Member
2 Star Member
Posts: 87
Joined: Tue Dec 27, 2016 1:08 pm

Re: Mach 3 and Sheetcam THC on/off Rules

Post by AdrianH »

Mach3 can be glitchy yes, but I will be honest and say that the THC On/Off has tended to be OK on mine but I tend to switch off THC when a small shape so it is off for the duration of a small cut rather than switch on and off during the cut, But! I would suspect it is also down to processor speed, RAM etc and what else the computer is trying to do at the same time. I have a rather old Dell Optimax GX 260 at this end so not the most powerful or quickest one going.

To manually test you macros work turning on and off THC you could always try the MDI screen and just enter the commands on the input line to check it is switching THC.

I think the post processor does not know or care what metal you have to cut what, thickness speed etc as it is the machine controller type physical interface to get things to work with your controller, such as a fanuc post for a fanuc type controller etc. All I can suggest is try it out start with basic shapes and see if you have issues.

If you have then look at going across to a Linux based PC controller with a real time clock kernel, or even ask on the Artsoft forum about performance of Mach4
Or the CandCNC controller etc. Mach3 is old now, so really for commercial production I would think something with future support would be better.

One last comment thinking about it, I think it was the speed changes that caused many of the glitches for me, a bit like a definite stop when it tried to change speed when approaching corners.

Sorry I can not be of more help.

Adrian
Last edited by AdrianH on Thu Sep 13, 2018 4:18 pm, edited 1 time in total.
TrinityFabworks
2.5 Star Member
2.5 Star Member
Posts: 186
Joined: Tue Apr 17, 2018 2:36 pm

Re: Mach 3 and Sheetcam THC on/off Rules

Post by TrinityFabworks »

Thanks for the reply! I'll do some testing with it. Thanks again!
Post Reply

Return to “Mach3 & Mach4 CNC”