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Best type milling cutter for maximum metal removal

cranny

Plastic
Joined
Aug 24, 2010
Location
GA
By that I mean we have a huge chunk of bronze(3,500lbs.) and our customer wants us to make chips out of it; that's it. Our customer melts the bronze down and their furnace lost power the other day. They were left with this big blob of bronze and they need it machined into shavings so they can start back melting it. Anyway, we're currently using a 6" face mill with positive geometry, .100" depth of cut at 48" IPM. We're just running a simple loop program that spirals in and then down again; rinse and repeat. The piece is in a Mori Seiki MV65 with 25hp at the spindle and a maximum spindle speed of 6,000. Any suggestions with another type cutter? I was thinking maybe something like a 2" milling cutter with radius inserts? Or maybe a 10" face mill? Though I'm not sure about the spindle load with that size cutter.
 
seeing how it might have slag or hard spots mixed in I would watch for sudden insert failures.
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many facemills with bigger inserts can take 0.2"DOC and ipt feeds of .010 to .020" ipt, if loadmeter near 100% than thats your machines limit obviously
 
Got a 3" indexable endmill? I'd spiral in with one of those, LOC maybe 1.5x to 2x D, using HEM/HSM/HFM cutting parameters. Maybe take all the cutters you're considering, plug them into HSMAdvisor, and see which gives you the highest MRR.
 
Ide just like to say that sounds like a hell of a fun time. Also it seems like you're in a better position then any of us to figure out which cutter works the best. I have zero actual input for you, other then have fun.
 
By that I mean we have a huge chunk of bronze(3,500lbs.) and our customer wants us to make chips out of it; that's it. [snip] The piece is in a Mori Seiki MV65 with 25hp at the spindle and a maximum spindle speed of 6,000.
How the hell are you holding this thing? Any chance we can get a picture or two?
 
I think 5axis has the right idea. Since Z is likely to be your stiffest axis. Plunge cut adjusting DOC and feed rate to max mrr.
As a aside someplace on the web is a video of a vmc plunge cutting Ti using thru the tool LN2 as coolant. Rather impressive.
 
I'll be the whipping boy with an alternate theory. Years ago I had a similar job... turning perfectly good metal into chips for the sake of the chips. Long story that involved a guy that checked himself out of a mental institution to pursue his dream of altering weather patterns with magnetics :)

I finally decided that the best tool was the biggest corn cob rougher we could chuck up, buried as deep as the flutes would allow. We ran it days and days on end, just chugging along. We tried the inserted method, but sooner or later, an insert went hen shit and wiped out a bunch of stuff. The corn cob cutter would get dull and give a bunch of warning. It seems like we had someone that would sharpen the cutters, so we kept a couple in rotation.
 
I would get a plunge cutter and use that toolpath strategy, probably the fastest way to remove material if your cam can program it decent.

Basically the dumbest CAM package on Earth will do it. Using basic point selection and a Drilling Toolpath, the user defines the cut parameters.

But I agree it's pretty quick. Drilling big ass holes is king, but you need the HP to push giant Drills.

R
 
Basically the dumbest CAM package on Earth will do it. Using basic point selection and a Drilling Toolpath, the user defines the cut parameters.

But I agree it's pretty quick. Drilling big ass holes is king, but you need the HP to push giant Drills.

R

Yes basically drilling holes but with not full engagement and the step matters a lot.
Once upon a time there were manual mills.
This step and plunge was how you made lots of stock go away fast and every machinist knew how to do it along with the step that worked for any given cutter.
Bob
 
the basics
1) you are limited by your machines hp. some cutters are more energy efficient that is remove more cubic inches per minute per hp but some cutters if you hit slag and destroy $1000 cutter within 10 seconds somebody saying they saved 1 hour but it cost a extra $1000. not sure how much they saved
.
2) cutting forces. when you put tons of force on a part you better make sure it wont move on you. sometimes small movement and there goes a $1000. cutter broken in pieces going flying
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3) tooling cost if you end up using a extra $500. in tooling to make chips sometimes spending only $100. on tooling but taking a couple hours longer is worth it.
 








 
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