Chip removal for deep cuts?

Chip removal for deep cuts?

Postby ctbjdm » Mon Sep 04, 2017 12:28 am

Hi all,

Was asked to build a large letter for an upcoming wedding - roughly 2' x 3', and 4" thick. (apparently that's an 'in thing' for weddings now - guests sign this big letter).

Used a 1/2" end mill to carve out the letter. I hadn't cut anything that deep before, and my chip removal would not remove the chips from the 1/2" 'channel' as it cut deeper. I ended up having to pause the cut, use a screwdriver to pry up the chips, vacuum them up with a shop vac, then keep going.

This took approximately forever (turning a ~25 min cut into several hours of cleaning and vacuuming).

What do others do for these deep cuts for chip removal? There must be a better way.

Things I considered after the fact:

1) Air compressor to blow out the chips - will make a big mess but would probably work pretty quickly
2) Cutting the project 2 sided, so it's not so deep. Not crazy about the extra work to flip it, but might work.

Other ideas?
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Re: Chip removal for deep cuts?

Postby Leo » Mon Sep 04, 2017 12:50 am

What was your Depth of cut and RPM and feedrate on your 1/2 end mill cutout. Also what kind of cutter and how many flutes on the end mill?


Without know the above, it's really near impossible to help determine the issues.
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Re: Chip removal for deep cuts?

Postby ctbjdm » Mon Sep 04, 2017 1:32 am

Thanks Leo - should have included that.

Depth of cut was 0.25", 12000 rpm, 100 ipm. This is the bit I was using: https://www.amanatool.com/46593-extra-long-cnc-2d-and-3d-carving-flat-bottom-x-0-10-deg-straight-angle-x-1-2-dia-x-1-x-1-2-shank-x-6-inch-long-x-3-flute-solid-carbide-zrn-coated-reduced-shank-router-bit.html

It was making chips (vs sawdust), and seemed to be cutting fine. The problem seemed to be that the chips were remaining in the channel as it cut, and it was such a long bit that the dust collector was a ways away from the channel it was cutting. (hopefully that makes sense).
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Re: Chip removal for deep cuts?

Postby Leo » Mon Sep 04, 2017 2:07 am

Sounds OK.

What happened if you didn't clean out the chips?

The flute length is pretty short at 1".

Up to 1" the chips should just clear away.

Deeper than 1" there is no flute to evacuate the chips - they have no place to go.

I have never cut anything that deep before. I wonder if a 1/4 inch end mill and making a pocket around the perifery about .275 or .325 would have worked.

Even using the 1/2 cutter but a groove .625 wide - some place for the chips to go.

I'm really not sure.
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Re: Chip removal for deep cuts?

Postby ger21 » Mon Sep 04, 2017 12:55 pm

I agree with Leo. A different tool, or a wider kerf is required. What I'd do, is for each pass, make a second pass 1/8" away from the part, giving you a 5/8" slot. If you have good dust collection, the second pass should remove most of the chips and dust.
If you don't have good dust collection, all bets are off.
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Re: Chip removal for deep cuts?

Postby 4DThinker » Mon Sep 04, 2017 2:43 pm

There is an option with the profile toolpath to do a last pass that steps over to the actual vector. You could use this with a 1/8" value or so, and break the profile into 4 separate tool paths each only as deep as your flutes are on that bit. You still would have chips in the slot when you get deep, but they should not jam in there as they do now. Sucking them out as you go may be all you need to do.

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Re: Chip removal for deep cuts?

Postby martin54 » Fri Sep 08, 2017 1:15 am

I've not machined anything near that deep as my gantry clearance is only 65mm but where I have a profile cut to do that is deeper than the length of the flutes on the endmill I just do as 4DThinker has suggested & just follow the bit round with the hoover hose, seems to work OK for me & no reason to think it wouldn't work if I was cutting deeper :lol: :lol:
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