Hello Guest it is September 19, 2019, 04:26:20 PM

Author Topic: Anyone Here Have Experience Milling 6061-T651 Wrought Plate?  (Read 28783 times)

0 Members and 1 Guest are viewing this topic.

Anyone Here Have Experience Milling 6061-T651 Wrought Plate?
« on: January 17, 2010, 12:21:17 AM »
I tried to machine some 6061-T651 wrought plate today, with rather disastrous results - four broken/dulled endmills later, I'm stumped.  If I go fast, the tools load up and break in seconds.  If I slow down enough to not get chip welding, the tool edges get destroyed VERY quickly - I ruined two brand-new high-quality HSS endmills in less than 24" of cutting each.  All the cutting edges were absolutely destroyed.  How the heck do you machine this cr@p?

Regards,
Ray L.
Regards,
Ray L.

Online Chaoticone

*
  • *
  •  5,589 5,589
  • Precision Chaos
    • View Profile
Re: Anyone Here Have Experience Milling 6061-T651 Wrought Plate?
« Reply #1 on: January 17, 2010, 01:43:50 AM »
Ray, I've used 2 flute Carbide with flood coolant and gotten pretty good results. Coated carbide does a little better. Can't remember using an HSS. What kind of feeds and speeds are you running? Cutter type, diam. and number of flutes? Make sure nothing is vibrating.

Brett 
;D If you could see the things I have in my head, you would be laughing too. ;D

My guard dog is not what you need to worry about!
Re: Anyone Here Have Experience Milling 6061-T651 Wrought Plate?
« Reply #2 on: January 17, 2010, 01:49:19 AM »
Ray, I've used 2 flute Carbide with flood coolant and gotten pretty good results. Coated carbide does a little better. Can't remember using an HSS. What kind of feeds and speeds are you running? Cutter type, diam. and number of flutes? Make sure nothing is vibrating.

Brett 

Brett,

I started with a 1/2" 3-flute carbide, 5000 RPM, 0.325" DOC 30 IPM, heavy mist coolant.  It loaded up and broke almost instantly.  I then went to a 1/2" HSS uncoated 2-flute, 3100 RPM, 0.175" DOC, 10IPM, very heavy mist coolant.  It didn't load up, but the cut quality was awful, and after cutting about 24", the tool was destroyed.

Regards,
Ray L.
Regards,
Ray L.
Re: Anyone Here Have Experience Milling 6061-T651 Wrought Plate?
« Reply #3 on: January 17, 2010, 01:50:47 AM »
What's odd is, I cut some smaller features, using 1/8" and 3/6" uncoated HSS 2-flutes, 8K RPM, 10 IPM, and they came out OK - Not great, but OK, and the cutters didn't seem to be damaged.

Regards,
Ray L.
Regards,
Ray L.

Online Chaoticone

*
  • *
  •  5,589 5,589
  • Precision Chaos
    • View Profile
Re: Anyone Here Have Experience Milling 6061-T651 Wrought Plate?
« Reply #4 on: January 17, 2010, 02:03:36 AM »
Hey Ray, I get 4584 RPM for the 1/2 HSS 3 flute at 41.26 IPM.

See if this link helps you any.

http://precisionchaos1.com/support.htm

Brett
;D If you could see the things I have in my head, you would be laughing too. ;D

My guard dog is not what you need to worry about!
Re: Anyone Here Have Experience Milling 6061-T651 Wrought Plate?
« Reply #5 on: January 17, 2010, 02:13:07 AM »
Hey Ray, I get 4584 RPM for the 1/2 HSS 3 flute at 41.26 IPM.

See if this link helps you any.

http://precisionchaos1.com/support.htm

Brett

Brett,

The HSS tool is a 2-flute.

Regards,
Ray L.
Regards,
Ray L.
Re: Anyone Here Have Experience Milling 6061-T651 Wrought Plate?
« Reply #6 on: January 17, 2010, 03:20:28 AM »
Wasn't the titanic made of that? 5140???
Re: Anyone Here Have Experience Milling 6061-T651 Wrought Plate?
« Reply #7 on: January 17, 2010, 03:30:32 AM »
 :o 5000 Rpm? O>MG

Offline Sam

*
  • *
  •  988 988
    • View Profile
    • hillbillyhilton.com
Re: Anyone Here Have Experience Milling 6061-T651 Wrought Plate?
« Reply #8 on: January 17, 2010, 03:49:33 AM »
Might be the type of coolant your using. I have NEVER gotten satisfactory results using anything other than an oil soluble coolant with aluminum. Looks like motor oil, then milk when mixed. Usually, I can get pretty aggressive with the cut, too. Coolant like koolmist or similar water based coolant is pretty much horrendous. Maybe I've always went about it all wrong, but that's my limited experience with cutting aluminum. I've never tried 5K. Might need more of a flood than a mist, additionally. I'm no expert with aluminum, so take all above with a grain of salt.
"CONFIDENCE: it's the feeling you experience before you fully understand the situation."

Offline simpson36

*
  •  1,374 1,374
    • View Profile
Re: Anyone Here Have Experience Milling 6061-T651 Wrought Plate?
« Reply #9 on: January 17, 2010, 05:05:35 AM »
Kool Mist is not good in my experience. I have tried a couple of lubes, but keep coming back to tapmatic tapping fluid. They now have an aqueous version that is not specd to be diluted, but I cut it about 3:1 with water and put it in a spray bottle with very good results, but for anything heavy, I still have to fall back to the tapping fluid.

Cutting tools . . . think in terms of chip load and not IPM. I have just completed my new mill and have not cut anything with it yet, but with my previous mill, all I could get was .001 per tooth before trouble started.

HSS if fine is the tools are excellent quality and have a smooth bright finish and are razor sharp. My experience with el-cheapo import cutters (Grizzly, etc) is exactly as you describe. Using a brand name cutter makes a huge difference.

There are some cutters that are made especially for aluminum with a higher helix and special coatings that prevent the dreaded build up on the tool. Once the aluminum melts and attached to the cutter you have only seconds before the tool snaps, so you usually wont get the chance to stop and clean the cutter.

Bottom line is you have to have sharp tools and keep them cool. Blow air on the cutter constantly to keep it cool, with or without mist. The MOST important thing is chip load. If you get that right, then the vast majority of the heat will go overboard with the chip. If you get it wrong, the heat goes into the workpiece and the cutter.  

Oh yeah and the two most important words in aluminum cutting: climb mill.


« Last Edit: January 17, 2010, 05:08:14 AM by simpson36 »