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Milling the best possible finish on this aluminum surface

Peroni

Cast Iron
Joined
May 18, 2007
Location
Yadkinville, NC
I've been tasked with trying to find some sort of cutter to mill the red surface pictured. I have about .175 square between the outer islands. Material is 7075 aluminum. This is all about surface finish, customer would like something around a 2ra. Thoughts?

DWG-017686 REV C TOP SURFACE REF v1.jpg
 

Finegrain

Diamond
Joined
Sep 6, 2007
Location
Seattle, Washington
I've been tasked with trying to find some sort of cutter to mill the red surface pictured. I have about .175 square between the outer islands. Material is 7075 aluminum. This is all about surface finish, customer would like something around a 2ra. Thoughts?

View attachment 330511

2ra what units? If μin, then this is at the limits of lapping, so I think milling is not possible. If μm, then no problem, any good new sharp endmill should work.

Regards.

Mike
 

Ianagos

Stainless
Joined
Sep 23, 2014
Location
Atlanta
2 ra sounds to me very very smooth.

If you want to do it on the mill mcd inserts are probably going to achieve about the best finish possible. Surface will look like a mirror but like above poster said may still not be that smooth. Pcd will also look good but I believe mcd(never used it myself) will be even better
 

Conrad Hoffman

Titanium
Joined
May 10, 2009
Location
Canandaigua, NY, USA
The geometry of the part makes it very difficult. You can't use anything like a fly cutter. I don't think you can chuck it up and turn it. If you could, diamond turning would get you anything you needed. I'm assuming 2 microinch Ra because 2 micrometer Ra would be cake.
 

Ianagos

Stainless
Joined
Sep 23, 2014
Location
Atlanta
The geometry of the part makes it very difficult. You can't use anything like a fly cutter. I don't think you can chuck it up and turn it. If you could, diamond turning would get you anything you needed. I'm assuming 2 microinch Ra because 2 micrometer Ra would be cake.

Not sure on part size but he could use a small fly cutter or insert mill and go diagonal corner to corner
 

Mark P.

Aluminum
Joined
Sep 1, 2021
I used to machine torpedo vanes. I got great results when I used mist coolant system. Machine had a 900 rpm max on the 50 taper side but the finishes were close to spec. It was just a small 2 1/2 Seco cutter with APKT inserts too.
 

Houndogforever

Hot Rolled
Joined
Oct 20, 2015
Location
Boring
I've been tasked with trying to find some sort of cutter to mill the red surface pictured. I have about .175 square between the outer islands. Material is 7075 aluminum. This is all about surface finish, customer would like something around a 2ra. Thoughts?

View attachment 330511

Well, I'd like to be about 100lbs smaller and have a better memory, but what are the functional requirements for that surface?
 

Milland

Diamond
Joined
Jul 6, 2006
Location
Hillsboro, New Hampshire
Any process is going to be compromised unless the spindle and axis control is in top shape. If the customer really wants/needs such a surface finish, it may require an air bearing spindle and linear travel machine to take advantage of even the best diamond cutter.
 

Bogie83

Plastic
Joined
Mar 22, 2020
Location
Portland Metro
Houndogforever

Hey there. So I tried responding to you the following 3 days or so after you messaged me. But it kept saying your inbox was full. Just tried again, and still says the same thing
 

Mechanola

Stainless
Joined
Mar 21, 2011
Location
Äsch
What a stupid design! Typical CNC trap. The four outer studs should be made separately and added. That way you had free access to the central plane. Then, of course, you’d put the part(s) on a lapping plate and have any desired smoothness.
 

trochoidalpath

Cast Iron
Joined
Jan 17, 2016
I've been tasked with trying to find some sort of cutter to mill the red surface pictured. I have about .175 square between the outer islands. Material is 7075 aluminum. This is all about surface finish, customer would like something around a 2ra. Thoughts?

Try a Fraisa NX. I believe they can produce 0.1um Ra and come in tiny (3mm?) sizes. For sure when I tried them for floor finishing I was astonished.
 

PHANG

Plastic
Joined
Oct 13, 2021
You can try to use a carbide bullnose endmill to facing it. if possible going to higher rpm with low feed rate.
after out from machine, direct use dish wash liquid to wash your part and blow it dry and keep it in close container with put in the silica gel pack together.
it to make sure the container inside low humidity. it prevent the part surface oxidation. cause the material aluminium 7075 easy to oxidized.
 








 
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