Finish allowance on spiral pocket over cut

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mariusl
Posts: 25
Joined: Wed Jul 27, 2011 2:56 pm

Finish allowance on spiral pocket over cut

Post by mariusl » Sun Jun 03, 2018 6:17 am

Hi Les
I used the finish allowance feature on a spiral pocket cut and found that the allowance caused the an over cut of the same size. It does show correctly on screen but the on the part it comes out wrong. I tried a negative number and that shows up as over cut on the screen but I did not cut a part with that setting as I know it works. I use it a lot to over cut a tight fitting part.

Look at the first part in the job.
Attachments
rotary motor mount LH.job
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Les Newell
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Posts: 2005
Joined: Thu May 11, 2006 8:12 pm

Re: Finish allowance on spiral pocket over cut

Post by Les Newell » Thu Jun 07, 2018 11:27 am

Sorry for the delay in replying. If you see the tool path change on the screen it will change when you run the post processor. The screen is just a specialized post processor so you will get the same geometry when you run the post.

mariusl
Posts: 25
Joined: Wed Jul 27, 2011 2:56 pm

Re: Finish allowance on spiral pocket over cut

Post by mariusl » Thu Jun 14, 2018 10:31 am

That was my understanding always but in this case the result is not correct. It is fine for all other operations but not spiral pocket. I re cut the same parts but used contour operation and the result is correct. There seem to be an issue with spiral pockets

mariusl
Posts: 25
Joined: Wed Jul 27, 2011 2:56 pm

Re: Finish allowance on spiral pocket over cut

Post by mariusl » Sun Jun 17, 2018 9:22 am

I forgot to mention that it is the development release

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Les Newell
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Posts: 2005
Joined: Thu May 11, 2006 8:12 pm

Re: Finish allowance on spiral pocket over cut

Post by Les Newell » Mon Jun 18, 2018 3:49 pm

SheetCam works out the cut offset amount by taking the tool radius then adding the finish allowance. It uses exactly the same maths for positive and negative finish allowance so if negative finish works, positive has to also work.

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