[John Roberts]

Hi I have a problem in PathPilot regarding tool offsets and need help!

I am new to Pathpilot and Tormach. After some time setting up my new Machine (770) I created my tool table to apply tool offsets as per below.

1. Lowered spindle nose to Z height setter to apply 0 offset to T0.
2. Measured each tool on Z height setter and added each value into the tool table as per Tormach's instructions.

Set up before machining.

3. Fixed work piece to table.
4. Called T50 (Haimer), pressed M6 G43 button and lowered on to job until it showed 0
5. Zeroed Z DRO
6. Removed T50 and replaced with required tool (T6)
7. Typed T6, pressed M6 G43 to apply tool length ( in my case 76.97mm.) This value is
displayed next to M6 G43 button.
8. I lower Z axis so that T6 is 10mm above the work piece and the value in the work DRO is
10mm which is what I would expect. All good so far so I thought.

9. As soon as I pressed Cycle Start to start machining the displayed tool length (next to M6
G43 button) lights up red and shows 0.000 offset. The work Z DRO changes value and
the cutter crashed in to job!

I have watched all the videos on this subject but am still at a loss.
I am using Visualmill to create the G code with mach3 post processer. PathPilot does not like G40.1 or G50 so this was changed to G40 and G50 was deleted.

Any help will be appreciated.

John.

[cncbasher]

John,
Pathpilot has Linuxcnc in the background , their are many differences between Mach3 also , the posts are not the same , although both are close decendants of Fanuc compatability .

i feel you may have not cleared previous tool offsets first , amongst a few other possibilites , take a look on Linuxcnc.org for other tool offset problems , i'm on at the moment with modifying linuxcnc and also pathpilot , so i'll look a bit closer

send me your gcode offending file and your post processor , and i'll check it out and get back to you .

i must admit at times tool offset problems come and bite me too , lol .
be wary of tool offsets in any cam programs , and tool offsets saved in the tooltable , they can cause never ending crashes .
i tend to use the cam tooltables more than anything , and set the tool table in linuxcnc to 0 ,and really only use the linuxcnc tooltable for wear offsets

i'll stick my neck out and say it will be a combination of a few things that caused your problem .
anyhow send me your files and lets see if we can hunt it down

[John Roberts]

Thanks for your input. Here is the first few lines of code.
G00 G49 G40 G17 G80 G90
G21
(MOp Set)
( Profiling counterbore)
M6 T6
M03 S5000
G00 Z6.0000
X-40.3989 Y-0.0196
G01 Z0.2700 F500.0
X-40.3865 Y-0.2487 Z0.2295 F300.0

With regard the post Mach 3 post processer I am not sure how to sent that to you.

Looking at the mach 3 processer within Visualmill. In the start/end tab the following is displayed.

(START_CHAR)
(SEQ PRECHAR)(SEQNUM)(DELIMITER) G00 G49 G40 G80(OUTPUT_MODE_CODE)
(SEQ_PRECHAR)(SEQNUM)(DELIMITER)(OUTPUT_UNITS_CODE )

Not sure if this info is what you need.
The latest Version of Visualmill 2015 has a post for PathPilot. and will upgrade if needed if this is found to be the problem.

[cncbasher]

you can download new post processors here MecSoft Corporation: Download Posts

also G49 needs to be called immediately before a toolchange

i.e
G49
M6T6 G43
if G43 is not called after toolchange then the tool table will not take effect

[cncoperator]

This should answer your question starting at minute 2:25 https://youtu.be/0cM32grBMvo?t=147

[John Roberts]

Many thanks to CNCbasher and cncoperater for your reply's.
On my previous hobby CNC mill I never used tool offsets. Each time I changed a tool I zero'ed on part. I was lead to believe that Mach3 post would work on Pathpilot. but I suppose could be altered to do so.
The simplest option for me is to upgrade Visualmill to 2015. Which is what Mecsoft recommended I did in the first place! I have already had an expensive upgrade with them earlier in the year and was reluctant to give them more money.
One on said that CNC hobby was going to be cheap!
I recognise the importance for learning G code and understanding Linux and will start to learn at least the basics. I love this forum because there are so many out there willing to help others.

[JohnToner]

Do take a few minutes to learn at least the most basic G Code commands. With just G0, G1, G2, and G3 you should be fine with pockets and profiles. Practice on some scrap or even a piece of 2x4. After you're comfortable with those basic translations, give cutter radius compensation a shot. Even if you plan never to manually code, a basic knowledge of G Code will prove to be useful.

[pickled]

Do take a few minutes to learn at least the most basic G Code commands. With just G0, G1, G2, and G3 you should be fine with pockets and profiles. Practice on some scrap or even a piece of 2x4. After you're comfortable with those basic translations, give cutter radius compensation a shot. Even if you plan never to manually code, a basic knowledge of G Code will prove to be useful.

This is sage advise here and can help you troubleshoot why your CAM software isn't doing what you told it to do! Developing an understanding of work offsets is a great advantage too.

[John Roberts]

I have bought Peter Smid book (CNC programing Handbook) for some light reading!

[JohnToner]

That book and a few scraps of metal, wax, or wood will take you a long way. Remember, there are only three basic moves possible: +/-X,+/-Y, and +/-Z and they will do a lot for you.

[mountaindew]

I have bought Peter Smid book (CNC programing Handbook) for some light reading!

hehe
Couple chapters in there worthy of a 4 credit our college course!