Editing post processor G90 to G91

[Anonymous]

I would like to change grbl turning (from Fusion CAM site) post processor. 

I need a G-code incremental (G91) not absolute (G90).

I am trying to edit it, but I dont understand why dont work

I have a Post Processor Training Guide (from AUTODESK site).

-a variable to switch between g90 and g91,  g90 works, g91 not

screenshot in the attachment

Thanks!

[HughesTooling]

It would be a lot of work to change a post from absolute to incremental. You'd need to edit all the functions that output coordinates so they calculate the incremental move. Why do you want to use incremental anyway as it will be less accurate and accumulate errors.

Mark

[seth.madore]

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@HughesTooling wrote:

 Why do you want to use incremental anyway as it will be less accurate and accumulate errors.

Mark

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^THIS^

[Anonymous]

I have access to old lathe machine with NC control, only incremental.

[Anonymous]

The question is: If it is so complicated and lot of work, maybe take it to a specialist?

[seth.madore]

A Post Processor specialist would be your best bet, but I'm just going to caution you: While their services are worth their weight in gold, it does not come cheap. If this was a "free-to-you" lathe, be prepared to spend a fair bit of coin to get a post that is custom built for your needs.