Aluminum Fun :-(

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atrueresistance
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Aluminum Fun :-(

Post by atrueresistance » Wed Mar 16, 2016 2:09 am

Well I was trying to mill some aluminum for the feet on some speakers. Simple enough right?

Image

I chose to do this in 2 toolpaths. Since I'm using an 1/8" bit for all this, one to rough out so only 1/4" is left for the contour. My personal thought on this was then the chip evacuation would be easier since the pocket was milled and there was a very small amount of material left to cut on the final shape.

1.5 to 2 hours in looking good.
Image

I used a fairly moderate setting in GWizard. https://goo.gl/photos/bdA5rraKTP9zFL7w5

But alas not great results. I stopped this before it went catastrophic.
Image


What else has everyone been running aluminum at? I can't see the carbide create settings since I get a blank screen when loading into it.

Edit:
It did make it .24 inches down before failure. Actually quite well up to that point.
Image

Code with failure
Cutting Feedrate 51in/min
10 in/min lead in lead out
8 in/min plunge
Max Roughing Stepdown .015 inch
Optimal Load .04 in
dewalt maxed out
Last edited by atrueresistance on Thu Mar 17, 2016 1:36 am, edited 2 times in total.
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WillAdams
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Re: Aluminum Fun :-(

Post by WillAdams » Wed Mar 16, 2016 2:16 am

Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

atrueresistance
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Re: Aluminum Fun :-(

Post by atrueresistance » Wed Mar 16, 2016 2:57 am

I know it is easy to paste a link. I've already read over that a few times. Not a lot of 1/8" bit references. How about we provide some valuable input?
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WillAdams
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Re: Aluminum Fun :-(

Post by WillAdams » Wed Mar 16, 2016 3:37 am

Unfortunately, what's at the link seems to be everything that everyone has shared thus far --- if there's anything else, I'd be glad to know of it.

I think it's great that you are trying to elicit more information, but your post didn't mention that you'd referred to the wiki, so my assumption was that you hadn't consulted it, hence the link. My own cutting results were w/ a 1/8" endmill, so there's at least one exemplar there, hence the assumption. Last I checked, the settings from Carbide Create weren't optimized.

Strange that G-Wizard is yielding such poor results --- have you contacted the CNC Cookbook folks?
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RobCee
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Re: Aluminum Fun :-(

Post by RobCee » Wed Mar 16, 2016 10:44 am

Looking at the video in your link (other pics don't seem to be showing) I would suggest that your feed rates are way too fast.

Cutting aluminium is hard on these machines and you need to be conservative with your speeds and feeds, particularly at the beginning. A tool like G-Wizard is very helpful, but I have found it to be overly optimistic about achievable rigidity in practice. I only have an SO2, so my rigidity is lower than the newer SO3.

Cutting deep is very difficult with a hard material like aluminium, as the chips need to be evacuated to help reduce the shocks on the cutter.
Deep cuts are where the depth of cut is more than twice the diameter of the cutter, so you need to be much more careful when you go past this sort of depth.

You are correct that making two cuts is helpful, as the chips have somewhere to go, which is outside the direct cutting path. I have found that sometimes you need to go down level by level as shown here on the right. This minimises the stresses on the cutter in such a deep cut and keeps the cutter free to evacuate the chips.
CutStyle.jpg
CutStyle.jpg (47.01 KiB) Viewed 1292 times
I don't know what CAM you are using, but I have found that CamBam allows you to specify a cut width greater than the tool diameter, which forces it to behave like the cuts on the right (B) in the above image.

If you can, a 1/4" shank cutter with 1/8" cut diameter will be much more successful, due to its rigidity.

Good luck with your project!
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DRobs86
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Re: Aluminum Fun :-(

Post by DRobs86 » Wed Mar 16, 2016 11:25 am

Non SO machine

3.175mm endmill 2 flute
DW660 tool stuck at 30k rpm
400mm min cutting feed
Long ramps into cut
0.5mm depth of cut
Those settings made a nice piece for me in quarter inch 6061 plate.

cvoinescu
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Re: Aluminum Fun :-(

Post by cvoinescu » Wed Mar 16, 2016 2:21 pm

Don't forget, the alloy matters a lot. Harder alloys with a fine grain structure (6082, 6005, 6061, 6060) will cut well. Softer (6063) or larger-grained (5083) will not cut as well. Really soft stuff is very hard to machine (1050, which is what cheap plate is made of, and the 1000 series in general).

For deep cuts, I hear trochoidal milling works nicely, if your CAM program supports it.
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JeromyReno
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Re: Aluminum Fun :-(

Post by JeromyReno » Wed Mar 16, 2016 4:09 pm

the pictures dont show up on my computer can you describe what its doing.

cvoinescu
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Re: Aluminum Fun :-(

Post by cvoinescu » Wed Mar 16, 2016 5:57 pm

They don't show on mine either.
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twforeman
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Re: Aluminum Fun :-(

Post by twforeman » Wed Mar 16, 2016 6:04 pm

It looks like the images are hosted at Google. They are not visible to people other than the owner.

You need to make them publicly available or host them at Imgur like the first one.
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