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Finish allowance on spiral pocket over cut

Posted: Sun Jun 03, 2018 6:17 am
by mariusl
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.

Re: Finish allowance on spiral pocket over cut

Posted: Thu Jun 07, 2018 11:27 am
by Les Newell
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.

Re: Finish allowance on spiral pocket over cut

Posted: Thu Jun 14, 2018 10:31 am
by mariusl
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

Re: Finish allowance on spiral pocket over cut

Posted: Sun Jun 17, 2018 9:22 am
by mariusl
I forgot to mention that it is the development release

Re: Finish allowance on spiral pocket over cut

Posted: Mon Jun 18, 2018 3:49 pm
by Les Newell
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.