RunRyder - Excessive wear on carbine end mill bits

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CAD - Engineering - Technical > Excessive wear on carbine end mill bits

helicopter34
Veteran
Location: New Jersey, exit 82

I don't know what I am doing wrong, but I seem to be wearing out rather quickly the end mill bits. They are carbide bits and I'm only cutting aluminum. There seems to be some small roughness forming on the cutting edges. I cut at around 500-800 rpm on a 1/2 inch bit.

Make it idiot-proof, and someone will make a better idiot

07-03-2004 Over year old.

HOMEPAGE

Peefor
Veteran
Location: St Albans UK

H34

Try some coolant on the bit, preferably a gentle spray, as opposed to the occasional slosh with a brush.

What seems to happen is that the aluminium welds itself to the cutting edge, and prevents it cutting cleanly. The coolant helps prevent this.

Experiment with the feed speed as well, as well as the rotational speed. What is important is the overall amount of metal removed / per minute.

Pete

07-03-2004 Over year old.

goof2
Heliman
Location: Bristol,CT

kerosene is a great coolant on aluminium
it prevents the build up on the bit

07-03-2004 Over year old.

Dazzler
Elite Veteran
Location: Ohio

Not sure what type of bit it is, but if it is a TIN coated bit, most likely that is your problem, Aluminum prefers to be cut with an uncoated grade of carbide, their are some coated grades that work well on Aluminum which is PVD type coatings. If you are using a bit, and it is gold coated then that is likely your problem.

If you are using a non coated bit, and experiencing excessive wear, then your speed is likely to slow, there is nothing worse on carbide than running it too slow, also use bit with a high positive shear to the cutting edge.

Daz...

07-03-2004 Over year old.

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TMoore
rrProfessor
Location: Cookeville, TN

helicopter34,

Dude, 500-800 rpm on a carbide endmill in aluminum is just plain wrong. A .5 OD cutter at 800 rpm is only running 100 SFM. This is the speed that you could run in steel with a lousy machine and a poor setup. Are you using a real machine tool or a toy? It makes a difference. How much horsepower do you have available and how tight can you hold the workpiece? 2,3 or 4 flute cutter?

Once I know a little bit more I can help you.

Terry

07-03-2004 Over year old.

HOMEPAGE

helicopter34
Veteran
Location: New Jersey, exit 82

Large machine

Yeah its a large machine in a University machine shop. I don't remember the horsepower off hand, but its probably not the problem. Its a 4 flute bit, with a silvery powdery coating, it think I might have heard someone say it was titanium something coated, but I'm not sure.

What rpm should I be using, I guess for 300-500 SFM it should be like approx 1200-2200 rpm.

Make it idiot-proof, and someone will make a better idiot

07-03-2004 Over year old.

HOMEPAGE

TMoore
rrProfessor
Location: Cookeville, TN

From the sound of it you have an uncoated 4 fluted carbide endmill. 4 flute end mills don't work especially well in aluminum. If it is an enclosed CNC vertical machining center a 2 or 3 fluted is better but you could run at 8,000 rpm and .25 DOC at full WOC at anywhere from 50 -100 ipm. If you do this flood the cutting area with coolant and let her rip. Just as precaution program the desired cutting speed and then back off on the speed and feed overrides, once you hear what is going on with the cutter sneak up on the feeds and speeds based on the load meter and sound. Actually 10,000 rpm isn't too fast but once you are at that speed you need balanced holders and I don't know what university you are in or what their capabilities might be.

HSS steel actuall roughs aluminum better than carbide.

If we are talking about a Bridgeport type knee mill 3600 is all you got and you will have to work accordingly. Use mist coolant if you have it. From the sounds of things before you might have been running so slow that you were actually getting aluminum build up on the cutter.

Terry

07-04-2004 Over year old.

HOMEPAGE

Torkroll
Senior Heliman
Location: Bakersfield Ca

Use a 2 flute, 6000 rpm 20 inches per minute, only cut .150" inch deep and keep stepping down .150" and use coolant.

This is a conservative starting point. @ 6K you could go to 80 ipm, later.

It'll cut way better !!
Notice the sound difference.

(ps: having the workpiece mounted real ridgid is important)

07-07-2004 Over year old.

jerrythercpilot
Veteran
Location: --South Florida --

Quote
Its a 4 flute bit, with a silvery powdery coating, it think I might have heard someone say it was titanium something coated,

Titanium Carbo-Nitride

Light travels faster than sound, thats why some people appear so bright UNTIL you hear them speak.

07-15-2004 Over year old.

TMoore
rrProfessor
Location: Cookeville, TN

There are only a few coatings in common use to day:

TIN: titanium nitride Yellow in color
TiALN Titanium aluminum nitride Purplish in color

PCD via particle vapor deposition prohibitively expensive, you won't see this one too often.

TM

07-15-2004 Over year old.

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jerrythercpilot
Veteran
Location: --South Florida --

TMoore,
PVD=Physical Vapor Deposition, more specifically its done by Cathodic Arc (Cat Arc).

You are correct the TiAlN is used (I forgot about this one) as it is more oxidation resistant than TiN. TiN is capable up to 1000-1100F and the TiAlN is capable up to 1400F. So it is used for tool bits where high speed and possibly high heat and oxidation conditions.

Light travels faster than sound, thats why some people appear so bright UNTIL you hear them speak.

07-15-2004 Over year old.

NEBULA
Heliman
Location: Greensboro,NC-USA

TMoor is correct

Actually if your going to mass produce these parts and if it will fit the profile of your part, and your wallet. A cutter with DIAMOND inserts will last weeks if not months if flooded properly.

P.S. Probably will have to bump up the SFM also buy another 15 to 30% aluminum and diamonds go good together on machine tools you can just about run the machine wide open!!!!!$$$$ Hope you can deburr fast hehe

Life is a freek show

08-12-2004 Over year old.

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CAD - Engineering - Technical > Excessive wear on carbine end mill bits

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