Cutting off 6061-T6 aluminum bar leaving an orange peel effect?

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bsmith

Plastic

Joined

Dec 23, 2011

Location

MA

• Apr 26, 2018

• #1

Just curious if any one else has experienced this? We've tried many types of inserts and it doesn't seem to help. We've verified the cut off blade is on center and have tried adjusting it a little below center too. I'm not sure this isn't an issue caused by the actual aluminum substrate. I think the quality of materials being sold today isn't what it was 20+ years ago. I could be wrong on this?
A light sanding and tumbling will generally remove it but I'd like to have a clean finish dropping the part off with no secondary process. It doesn't happen on 2024 or 7075 (or any other grades of steel).

It's funny, I don't get out on the shop floor too much anymore so I don't remember this was a problem when I was writing programs.

 

G

Gobo

Titanium

Joined

Jun 4, 2013

Location

Oregon, USA

• Apr 26, 2018

• #2

Share some info as to your process. Are you using a neutral insert, or a right or left handed insert? Solid cutoff blade, or adjustable? Interrupted cut?

 

D

dstryr

Diamond

Joined

Jan 22, 2010

Location

Nampa Idaho

• Apr 26, 2018

• #3

Rough part off as far as you can but still leaving support to hold onto the part, back out, take a .005 finish pass with the part off tool and cut the rest of the part off the bar.

 

M

Milland

Diamond

Joined

Jul 6, 2006

Location

Hillsboro, New Hampshire

• Apr 26, 2018

• #4

Try a PCD insert. Only for Al use, of course. Well, and copper too.

 

T

Tedger

Aluminum

Joined

Nov 29, 2012

Location

Phoenix,AZ.

• Apr 26, 2018

• #5

Do a little searching around on this site and you'll find a few threads about this problem with 6061. It's been narrowed down to material. You can do things to minimize it, but if you have bad material, your boned. I was getting a lot of orange peel with SAPA before specifying Kaiser. It's a lot better, but every once in a while, I still get bad stuff.

 

Finegrain

Diamond

Joined

Sep 6, 2007

Location

Seattle, Washington

• Apr 26, 2018

• #6

Even on a good day, with a new sharp AL-specific 7* RH insert and Kaiser bar, I never get a surface finish nice enough to consider skipping a 2nd op to clean it up. Yes, vibe can fix a lot of things, but I'd rather just run a P2, instead of vibing just to clean up the parted face.

Regards.

Mike

 

david n

Diamond

Joined

Apr 13, 2007

Location

Pillager, MN

• Apr 27, 2018

• #7

You can play with different inserts til the cows come home..............It's the material....................over the years Kaiser has been the least problematic for me..............and I said least. It still has it's moments when poor surface finish rears it's ugly head. Oh and stringy chips...........that's one place Sapa seems to shine, it breaks a chip........................

 

david n

Diamond

Joined

Apr 13, 2007

Location

Pillager, MN

• Apr 27, 2018

• #8

Dug up an old pic.......................Here's a classic example.........................top is Kaiser. Bottom is Sapa. The Kaiser would have been even better had I did a back facing pass.........................

.............................

 

B

bsmith

Plastic

Joined

Dec 23, 2011

Location

MA

• Apr 27, 2018

• #9

Thanks everyone!
I thought it might have been the material. We've tried neutral along with right and left hand inserts. We've tried different grades and geometries recommended by Kenemetal, Sandvik and Iscar but nothing helps. Starting out 30 years ago I don't ever remember having this issue. Material quality has degraded over the years, I agree. SpaceX has a list of approved mill and Sapa has been banned and as I understand it they bought Alcoa's extrusion plants. Seems like Alcoa and Kaiser are primarily interested in cold finish products which are more profitable.

 

B

BALNH

Cast Iron

Joined

Oct 27, 2006

Location

New Hampshire

• Apr 27, 2018

• #10

We have the same issue with some of the bars we cutoff. Its not you. Seeing your in mass probably came from the same place as us.

 

C

carbonbl

Cast Iron

Joined

Apr 15, 2016

• Apr 27, 2018

• #11

bsmith said:

Thanks everyone!
I thought it might have been the material. We've tried neutral along with right and left hand inserts. We've tried different grades and geometries recommended by Kenemetal, Sandvik and Iscar but nothing helps. Starting out 30 years ago I don't ever remember having this issue. Material quality has degraded over the years, I agree. SpaceX has a list of approved mill and Sapa has been banned and as I understand it they bought Alcoa's extrusion plants. Seems like Alcoa and Kaiser are primarily interested in cold finish products which are more profitable.

Click to expand...

The statement about SpaceX's suppliers made me curious, and with a couple minutes of googling I found the "acceptable mills list" from 2017. Newer versions seem to be password protected.

https://spacex.com/sites/spacex/files/spacex_acceptable_mills_list_11may17.pdf

 

M

metlcutr55

Cast Iron

Joined

Jan 6, 2007

Location

s w NH

• Apr 27, 2018

• #12

probably not practical on production, but a huge gain can be made shutting off the coolant and using a brush with wd40 or kerosene or the like.