Toolpath order

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Robert L
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Toolpath order

Post by Robert L »

Hi gang,

I never miss a day reading this forum. Amazing info that I have absorbed over the years thanks to you all.
I make frames (12" x 18" x 1" thick) that need a .5" btm inside rabbet. Having trouble with tear out with the inside cut.
Using a pocket toolpath .3825 wide by .53 deep. Outside cut is great but that leaves .0625 of material left to remove with
inside cut.

Is there an option to do the inside cut first?
running VCP 8.5

Robert
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highpockets
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Re: Toolpath order

Post by highpockets »

A down cut spiral bit should help.
John
Maker of Chips

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Adrian
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Re: Toolpath order

Post by Adrian »

Not 100% sure what you mean but if you switch the pocket toolpath from offset to raster you get the option to do the outside cut first or last.

bravesoul
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Re: Toolpath order

Post by bravesoul »

Another possible fix, you show 9 passes for the cut. You might want to try 8 to a depth of 0.4711, and with a new pocket in reverse direction single pass to 0.53. See attached, only issue you may have is I am using ver9.
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Frame rabbet.crv
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Robert L
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Re: Toolpath order

Post by Robert L »

John, I am using a down spiral bit, always a new one as I do 60 of these each run.

Adrian, when I switch to raster the time is double and I don't see where the option is to do the outside cut last.

Bravesoul, don't see how that would help but will try it.

tomgardiner
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Re: Toolpath order

Post by tomgardiner »

Seeing as this is a repeating job, you might take the time to make a profile toolpath separate from the pocket that will give you a clean initial cut. I don't know the capability of your machine but you can test to see how little has to be removed to eliminate the tearout. You can merge the toolpaths so that each pocket and profile pass happen sequentially per part if more than one are done on the table.

Robert L
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Re: Toolpath order

Post by Robert L »

tomgardiner, A good thought. I considered that a few months back, maybe it's time to try it now.
The odd part is the the tear out gets milled away in another toolpath. Was just looking at other options
to reverse mill a pocket toolpath.

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Adrian
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Re: Toolpath order

Post by Adrian »

Robert L wrote: Adrian, when I switch to raster the time is double and I don't see where the option is to do the outside cut last.
Shouldn't be doubling the time just by switching to raster unless it's a very narrow pocket and you've got the raster running the wrong way. I always use raster as I can control the cut direction which speeds up most pockets for me.

Look at the preview and see which way the cut is running. If it's lots of short movements set the raster angle to 90 degrees and recalculate. The Profile Pass option is just under the Raster Angle setting and can be changed via the dropdown choices.

Robert L
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Re: Toolpath order

Post by Robert L »

Adrian,
Yes, the pocket is a hair over 3/8 wide. I have used the raster settings many times, very useful. Thanks.

tomgardiner
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Re: Toolpath order

Post by tomgardiner »

One machining technique I have seen on "big iron" machines is to take full depth cuts in successive passes from outside in, climb cutting. Reverse the cut for final pass. You can accomplish this with copies of the profile with reducing amount of machining allowance. This may prove to be faster for you and give a better finish than multiple depth of cut.

Tom

Robert L
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Re: Toolpath order

Post by Robert L »

Tom, I like the sound of that, will give it a go. Thanks.

Robert

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