My Z axis has gone crazy.

I am working on a part for my next CNC machine (Joe's 2006 r2) and for the most part, posting code from bobcad/cam v26 seems to work fine. Simulations are spot on and all looks ok. However, when I execute the job (LinuxCNC controlled Gecko G540) I seem to be losing the Z reference between features. That is to say, the first "feature" works well, then I get asked for a tool change. I am not changing tools, so I just click OK. This is when it gets weird. The second feature seems to get Z movement doubled in distance. The third feature, then goes back to normal in the Z travel but it's too high and doesn't even touch the stock.

Am I supposed to be "zerioing" the Z axis during a tool change sequence even id I don't change tools?

Sorry if this is obvious, but I am very confused as to why this might be happening.

Any ideas?

Corey

corey..

if you set toolchangeing.. and you say the T1 and T2 and Txxx same, then still you have to set zero.. even you don't change tool
you have to say the control heres the zero.. otherwise the last settings will come back..

in mach3 the tool length offset as much I remember the G53 is the zero and from G54- to G59 the work cordinata offset..

also theres the G43-G44 and for canceling the G49 code..

these are standard codes and I believe what youre using the Linux emc working same way..
that controlprogram also partially art fenertys program, so im very confident its close to all standard..


you also can save two program and each with one tool... it might saves a lot headache you...

Victor,

Thanks for the info and ideas. I am clearly a newbie with regards to g-code and how things reference each other. I don't mind setting zero, it's easy enough but it's I am not sure how to go about doing that using LinuxCNC (EMC2). The dialog asking for a tool change is modal and doesn't allow for setting zero. At least it doesn't appear to. I'll take a look around for that capability,

Thanks again!

Corey

Corey,

Check on setting for me and let me know if it helps you out.

Right Click on Milling Job inside your CAM Tree in BobCAD. Then go to Current Settings. Go to the Tab on the Left that says Multiaxis Posting.

In the bottom Right-Hand Corner, you will see Move List Coordinates. Below that is a Drop Down menu. In the drop down make sure it is set to Machine Compensation in Z only. If it is already set to that, then it could be something in your Post Processor not outputting correctly.

Let us know how that works.

I suspect you may have a stray G91 in there somewhere. Does your post happen to output this line before the tool change?

G91 G28 Z0.

If it does, make sure there is a G90 after the tool change.

Quote:

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Originally Posted by bloodbath500

Corey,

Check on setting for me and let me know if it helps you out.

Right Click on Milling Job inside your CAM Tree in BobCAD. Then go to Current Settings. Go to the Tab on the Left that says Multiaxis Posting.

In the bottom Right-Hand Corner, you will see Move List Coordinates. Below that is a Drop Down menu. In the drop down make sure it is set to Machine Compensation in Z only. If it is already set to that, then it could be something in your Post Processor not outputting correctly.

Let us know how that works.

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Just checked this and it is indeed set to "Machine Compensation in Z only"

Thanks for the tip.

-C