Pocket from inside out

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garv123
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Pocket from inside out

Post by garv123 »

Hi all,
As above, is there any way to set the start point of a pocket on the inside when using offset. I cant see any option for it. It was our default when using Artcam.
Using cut 2d pro now.
Basically when pocketing out plastic, a 40.4mm long pocket with a 20mm cutter, the cutter will run around the outside but the 0.4mm will wrap around the cutter and pull off before the cutter makes the final pass up the middle, if the first pass was up the middle this wouldn't be an issue.
This is just one example of the issue.

Any help appreciated.

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Rcnewcomb
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Re: Pocket from inside out

Post by Rcnewcomb »

Can you post your CRV file? When I do a pocket it starts in the middle.
- Randall Newcomb
10 fingers in, 10 fingers out
another good day in the shop

garv123
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Joined: Mon Nov 04, 2019 11:39 am
Model of CNC Machine: Maxicam m4

Re: Pocket from inside out

Post by garv123 »

Sample of a job attached
Attachments
10pe Shelves.crv
(145.5 KiB) Downloaded 34 times

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Adrian
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Re: Pocket from inside out

Post by Adrian »

I expect it's generating the toolpath like that as it's so close to being double the diameter of the bit the toolpath would be cutting air for the most part if it started in the middle. If you change it to a raster with the profile option set to last it should work the way you want it to.

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adze_cnc
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Re: Pocket from inside out

Post by adze_cnc »

Adrian wrote:I expect it's generating the toolpath like that as it's so close to being double the diameter of the bit the toolpath would be cutting air for the most part if it started in the middle.
Close. It's because the tool step-over is 60.2% (12mm) of the bit diameter (which is specified as 19.5mm not 20). Drop that step-over to less than 50% and all works as it should.

This is where having access to a test file makes debugging the problems so much easier.

Steven

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Adrian
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Re: Pocket from inside out

Post by Adrian »

The raster toolpath with the original settings will be faster though. Generally for long skinny pockets I tend to favour the raster over the offset.

garv123
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Joined: Mon Nov 04, 2019 11:39 am
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Re: Pocket from inside out

Post by garv123 »

adze_cnc wrote:
Adrian wrote:I expect it's generating the toolpath like that as it's so close to being double the diameter of the bit the toolpath would be cutting air for the most part if it started in the middle.
Close. It's because the tool step-over is 60.2% (12mm) of the bit diameter (which is specified as 19.5mm not 20). Drop that step-over to less than 50% and all works as it should.

This is where having access to a test file makes debugging the problems so much easier.

Steven
The stepover being less than 50% is a bit of a pain when theres more than just the skinny pocket in the job, it'll take a lot longer to do big jobs.

Same goes for using raster, if there is a L shape pocket it will be fast in one direction but slow to pocket in the other direction.

I'll start using raster for the long skinny pockets on their own for now. just need to try and keep these 3 CNC routers running as smoothly as possible all day.

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