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Opine on facemilling 7075

88Matt

By 88Matt,
in Industrial Forum

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Posted
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AB Tools Shear hog...use the honed inserts..I would recommend the use of a smaller, as opposed to larger diameter tool.

 

Those damn things are so free cutting....

 

But it will likely have to flipped a couple times to keep it flat

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Colin Gilchrist Proficient

Colin Gilchrist

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I have some 7075-T6 half inch sheets two foot square I am holding close to free state and need to flatten within .001in. Looking for the best facemill and inserts for cutting it.

 

Please opine.

 

Thanks

 

Why not get ground tooling plate, and have the flatness already dialed in before you get the material? (I know, sometimes you've got to use what is already on hand, rather than spending money on new material...)

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Newbeeee™ Community Regular

Newbeeee™

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Over here, tooling plate is 5000 series ally - so not as strong as 7075. But that may not be a problem depending on the application?

 

You could have bought T651 which is 2% controlled stretched. This straightens and also mechanically stress relieves the material which would be a big help in what you are about to try to achieve.

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88Matt Newbie

88Matt

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The material is speced by the customer for reasons I can't discuss here. I requested it to come in ground but obviously I didn't get it. So like always, "just make it work...yesterday."

 

The first batch was .75 thick and I used Mitee Bite step clamps for holding with a 2 inch seco octomill and f15m inserts to cut, it's what is currently available in the shop. Some of the plates required flipping a few times, other didn't.  Vibration has really been the enemy I've been fighting and keeping it in a reasonable cycle time.  Only shaving what is needed to flatten one side in a free state before flipping and bolting down.

 

Kind of been looking at the Mitsubishi's AXD series.  Anyone use them or like it?  I'll look at the AB Tool shear hog.

Thanks for the input.

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Newbeeee™ Community Regular

Newbeeee™

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I hate it when the material gets ordered before any process engineering happens.

Customer over the road from us makes their own commercial product.

Drawings say Aluminium or Stainless Steel - no specs, so the buyer just buys what the suppliers offer her - quite often the boys in the shop get some 316 where 303 would do nicely...

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Mjölnir Newbie

Mjölnir

Posted
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An ice vice is pretty good for this, it holds the first op in "free state"

 

today i learned ice vises are a thing after a couple minutes of web searching.

 

water expands when frozen. are commercial ice vises made to handle that expansion? if they didn't, seems to me it'd be easy to warp a thin plate.

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mkd Newbie

mkd

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today i learned ice vises are a thing after a couple minutes of web searching.

 

water expands when frozen. are commercial ice vises made to handle that expansion? if they didn't, seems to me it'd be easy to warp a thin plate.

well it expands evenly / upward but flood coolant really helps with free-state. :laughing:

 

 

edit; but if the OP is battling chatter, the key is to have fewer inserts touching the part. Years ago i used a face"mill" that someone cobbled together with a welder. Used a 35° turning tool. almost no cutting force and a really long cycle time. swinging a 1 FOOT circle, it was scary being in the same building with that ugly pile.

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civiceg Newbie

civiceg

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I would endmill it, low DOC and lowish SFM so you don't heat it up. When you are talking flat within .001 and that size its a pain, is it just a sheet or are there features? 

 

I  had to get an oval that size flat within .0007 and parallel with in .001. Was thin around the edges with no support, 3/4 endmill and flipping from low torqued mittebites to vac fixture and repeating 3 times. Establish one side in free state and suck that side down, cut on vac curls slightly and repeat process. The dimensions could have been achieved in two go arounds in all reality.

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mkd Newbie

mkd

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Over here, tooling plate is 5000 series ally - so not as strong as 7075. But that may not be a problem depending on the application?

 

You could have bought T651 which is 2% controlled stretched. This straightens and also mechanically stress relieves the material which would be a big help in what you are about to try to achieve.

man, i gotta study-up on materiel specs. I was doing battling a 7075 space part a few months ago. First part was perfect outta the gate. I even returned the extra piece of material.

 On re-order something changed with the material and i couldn't get it flat for sh1t.

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daryl_y Newbie

daryl_y

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I would not use a large face mill.  The Aluminum face mills we have here (Kennametal Fix Perfect) cut too free and do not do a very good job of getting a thin part flat. I would use a smaller 90 deg inserted end mill 2.00 Dia or less with a .12R or so on the inserts, something that might put a little stress back in the part.  I have had better luck getting parts flat when you face from the inside out like a pocket.

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jeff Newbie

jeff

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Kind of been looking at the Mitsubishi's AXD series.  Anyone use them or like it?  I'll look at the AB Tool shear hog.

 

Thanks for the input.

When it comes to facing aluminum, I've found Mitsubishi to be the best.  Unfortunately the facemill that NEVER chattered for me is discontinued, but the AXD are fantastic too.

We recently got a 4" Sandvik Century RA590 facemill (not cheap) and that thing is amazing for surface finish if you ever need a part smooth as a baby's a$$. You can dial each insert in.

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kunfuzed Rookie

kunfuzed

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Double stick tape, if it's practical in your situation.  Essentially free state, and should take care of the chatter since its "supported" over the entire part.  To get rid of chatter and get a better finish out of a facemill for stuff like this, I've also taken out all but one of the inserts... basically making it a flycutter.

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