It is currently Tue Aug 21, 2018 6:42 am


Need need help understanding how to modify postprocessor

Post BobCAD related questions and tips in this topic.
Posts: 1
Joined: Fri Dec 18, 2015 3:00 pm

Need need help understanding how to modify postprocessor

Postby villageblacksmith » Fri Dec 18, 2015 11:01 pm

I understand how to edit g-code after it has been generated by a postprocessor. I am needing help understanding how to modify the mach2 post for bobcad v21express so that it will generate it right the first time. In the beginning(2006), I didn't understand the need to have all programs backed-up. Of course, the computer died when it reached the expiration date. After we installed v21express and mach2 on the "new" one, we discovered that all was not well. We got it to generate the code more or less correctly, but it still has its quirks. For example, the m03 command is always at the wrong place, but we can edit that. On projects with lots of g-code it becomes quite burdensome. If you can help with that issue, I will call you a wizard!! The second thing that has distressed us is with the oxy-fuel torch. Before, when we programmed for its use, after selecting the oxy torch from the menu, a small dialogue box would pop up where we would enter the pre-heat value. The pierce time was programmed the same as the plasma torch. We are using a 6x12 plasma table built by plascutter out of Alberta, Canada. They are out of business. To recap: bobcad v21express with mach2 using both oxy-fuel and plasma. If you can solve this I will say you are a genius!! Now, I realize that your time is valuable, as mine also is. The first person (or wizard or genius) to set me back on the road with both problems will find in their mailbox(after pm'ing me your address) a check for 100 u.s. dollars. THE FIRST PERSON!! :D Thanks I am not a superscientist, I 'm just the villageblacksmith!!

Elite Contributing Member
Elite Contributing Member
Posts: 49
Joined: Sat Feb 22, 2014 1:42 am
Location: Sask. Canada

Re: Need need help understanding how to modify postprocessor

Postby f_armer » Sat Dec 19, 2015 4:15 pm

I'm not sure if I can be of help, I use BobCad, but not as a post processor, I use Sheetcam.
If you lost your original post processor with your computer crash, I'm not sure if you are aware, but you can download different ones to try from the BobCad site,
There are 7 different choices under BobCad V21 express, Plasma, Mach.
You could possibly edit the processor you have, in your Bobcad folders there should be a folder called 'Posts', under posts one called 'Mill' In that folder you should be able to find the processor you are using, it will have a .MillPst file name, then right click and 'open with..' use notepad as your choice, and it will let you edit the processor.
I have no idea on how to edit the processor to fix your problem though.
From what I have seen with Bobcad, compared to Sheetcam for post processing, there is no comparison, Sheetcam is the way to go.
I just use Bobcad to do Cad, then save as dxf, run it through Sheetcam, and cut.
Hope this helps
4x8 bulltear
Hypertherm pm45
Miller 252
Miller syncrowave 210

User avatar
Elite Contributing Member
Elite Contributing Member
Posts: 648
Joined: Tue Mar 04, 2014 8:36 pm
Location: Cheyenne, Wyoming

Re: Need need help understanding how to modify postprocessor

Postby WyoGreen » Sun Dec 20, 2015 12:57 pm

I also use sheetcam and have modified posts to fit my needs. What helped me in figuring out how the posts work, was to compare the g code printout to the post printout. The Sheetcam posts are kinda like the old basic programming language. ( I think they are written in LUA programming) You can read down thru them and relate what is written in the post as to what happens in the g code. If you end up modifying a post, be sure to back up the original.
I don't know what language BobCad posts are written in, but if you're lucky, it might be something similar to the Sheetcam posts that are fairly easy to modify.

Good Luck, Steve
Precision Plasma gantry
CommandCNC Linux controller w/Feather Touch & PN200 hand controller
HT-45 plasma cutter
Plate Marker
CNC Router table

Return to “BobCAD”

Who is online

Users browsing this forum: No registered users and 2 guests

Easyscriber engrave attachment for Hypertherm torch's