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Chopped Up Finish - Indexable End Mill on AL

sdinzy

Aluminum
Joined
Dec 21, 2019
Bought this end mill and these inserts to face a 1" wide surface, 6061. 1400SFM & IPT of 0.004" for an RPM of 4278 and a feed rate of 34ipm, DOC of only 0.01". Needless to say, the results were not as anticipated. I'm fairly new to machining, so it wouldn't surprise me if I had the inserts backwards or something ridiculous (I don't really think I have the inserts backwards :drool5:). WTF!

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Bought this end mill and these inserts to face a 1" wide surface, 6061. 1400SFM & IPT of 0.004" for an RPM of 4278 and a feed rate of 34ipm, DOC of only 0.01". Needless to say, the results were not as anticipated. I'm fairly new to machining, so it wouldn't surprise me if I had the inserts backwards or something ridiculous (I don't really think I have the inserts backwards :drool5:). WTF!

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Aside from the tool being a POS your set up is the main problem. its not rigid
 
I thought it might be the workholding. I would agree the tool was cheap. Ok so final verdict is workholding?
 
So I am no machinist either, but I can tell you that a flat faced insert like that is going to push off like crazy and if the part isn't absolutely ridid you'll get what you gotten. Use a nice new dead sharp end mill and you'll get much better results. It's aluminum and you will likely break it from stupid long before you wear it out. A smaller tool won't push as hard either so it will reduce the rigidity problem.
 
Honestly I don't know anything about inserts. Please educate me.

If its a TPG.. DO NOT buy it. Quite honestly, they should be outlawed. 1960's left over
garbage that even most home shop harry's won't even use anymore. Flat top, no geometry,
just garbage.

And if you paid anywhere near those prices, you got gang raped. But.. That is MSC's standard
operating procedure.

Even a standard APKT (80's technology) will work far better.

1 INCH APKT END MILL

And I'll agree, to get that kind of chatter, your work holding had to be sketchy.


Learning experiences. Aren't they great?
 
That style of insert cutter is essentially the worst thing you can use aside from bolting rocks (well, pebbles) to holder and trying them.

But forget that for a moment, you need to show us (in the machine) how you were holding the part.
 
shear hogs from ABtools.com or Ripper mills from Latheinserts.com

I run both and have for years on alum with great luck ,, but I well say with the finish your getting it has to be a bad setup as much as wrong tooling for the material.

I have also had good luck with the cheap-O face mills from Latheinserts.com ,, he has some alum inserts that seem to hold up for months and you cant go wrong on them for like $7 each ,,, I have one mill setup on a nonstop production part and its been a year on the same inserts and the finish it still holding ...
 
Like others said, post a picture of your set-up. It looks like you had something that would flex and vibrate like crazy, even with the proper tool. I could not image the noise it was making.
 
Hi Guys, Thank you for all the responses. The workholding itself is actually fine (5th Axis dovetail fixture), it’s just that due to the order of operations, the remaining extrusion supporting the part being faced provides very little rigidity; I can easily change the facing operation to occur much earlier in the process. *The sound actually wasn’t bad, relatively*

In regards to the inserts, thank you all for the wisdom. I tried researching inserts to the Nth degree prior to purchasing, but it just doesn’t seem to be a topic you can read about online. If any of you can recommend a product or type of product in order to point me in the right direction, I would greatly appreciate it! I don’t necessarily need a mirror finish, but the current finish won’t work ;-)
 
+1 to throw that tool away, they weren't very good when they were young, and now they are antiques.
No one has mentioned edge prep. Since the grade is listed as C5/C6 whatever that really means, it's probably a generic grade intended for steel, so it probably has a honed edge. Search here for edge prep for more explanation. An aluminum insert usually has a dead sharp edge with no honing, honing will make aluminum smear and will make an otherwise good cut very ugly, and make the part push away, and cause build up on the edge of the insert which makes even more trouble.
+1 on the ripper mills from latheinserts.com, they are more than worth the investment.
 
You are better off with a Chinese $40 apkt insert mill. I have never used anything with those old school inserts and I’m pretty impressed that you were able to buy them. You own a modern looking 5 axis machine. Sounds like you have some decent $$$ try calling a tooling rep for whatever brand you want.
 
If you don't feel like throwing it away, get a box of cheap inserts that have a normal nose radius, instead of those wide flats. Standard old TPG-322 or something. Uncoated.

Yeah, it's not a great tool but if you hold the part so it doesn't shake rattle and roll, and use an insert with a standard nose radius so the contact patch is small, you should be able to make it work.
 
Looks like you have a 4 maybe 5 axis mill? I'd try machining that surface with the side of an endmill.
You might get a little funkiness at the beginning and end of the cut, but once the tool is into the cut it stays engaged. Not like the constant pounding it's getting from that inserted tool.
 
Try Ingersoll's HiPos Alu line. They have a crowned back to keep the inserts seated at high speeds and a sharp polished cutting edge. They will make that TPG tool look like Stone Age technology.
 
Thank you Chip! It sucks buying stone age $hit not even knowing it was stone age $hit, but all part of the process I guess.
 
In regards to the inserts, thank you all for the wisdom. I tried researching inserts to the Nth degree prior to purchasing, but it just doesn’t seem to be a topic you can read about online. If any of you can recommend a product or type of product in order to point me in the right direction, I would greatly appreciate it! I don’t necessarily need a mirror finish, but the current finish won’t work ;-)

Go to all of the big name websites and download their literature or have them ship you a physical copy of their books.
Sandvik,Iscar, Kennametal, Mitsubishi Carbide, Seco,Garr, etc... they all have info on their tooling and their recommendations.
 
Despite the tool being a far less than optimal geometry it is capable of producing a far better finish than that. Something is loosey goosey. Likely the part but maybe something else. Hard to tell without more pics.
 
how about showing how the part was held down? that end mill, even with "no geometry", cannot be solely responsible for that result
 








 
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