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View Full Version : Endmill getting clogged up?????



Phil McCrackin
12-28-2008, 01:10 PM
When I try to mill Al, my end mill gets clogged up with Al very fast.

I have tried different speeds and feeds, but to no avail.

I am using the rule of cutting no more depth, than the cutter diameter.

I have tried the 2 flute and 4 flute designs. The Al actually gets welded onto the bit and I have to knock it off with an punch!

Would roughing end mills help with this, or is this just the nature of the beast.

I must be doing something wrong, because sometimes I can only mill 1 or 2 inches before it happens.

Do I have to use cutting fluid all the time? I have been trying to use compressed air to clean out the chips, and that works O.K., but not great.

Thanks

Davek0974
12-28-2008, 01:25 PM
Hi

I find coolant helps, lots of it.

Dave

Teenage_Machinist
12-28-2008, 01:25 PM
You will want to use oil or coolant. And a 2 flute end mill.

I would say try the speeds and feeds a bit more, or less depth.

lane
12-28-2008, 01:32 PM
Spray some WD40 on it while cutting. are brush on some kind of cutting oil. get you a 1 quart squirt bottle and mix up some coolant to spray on while cutting . just different ideas they all help.

Shuswap Pat
12-28-2008, 01:36 PM
There are a couple of things. First the type of aluminium. Some cast material is just palin crap to machine. Some of the sheet material - 6061, 7075 is much nicer to machine. Next is that your tools have to be razor sharp. If the endmill has any wear on it at all, it can rub, and pick up the aluminum.
Having said all of that, there is a special cutting fluid called A9, that works very well, especially for tapping. An alternate simple solution is to try a bit of Varsol, or WD-40 applied by spray, squirt or brush.

Good luck

Pat

Doozer
12-28-2008, 01:36 PM
Soft aluminum will gum up an end mill like crazy.
6061T6 is harder, and not bad at all.
And yes, lube helps a lot.
Coolant is good, but I too like WD40.

--Doozer

Carld
12-28-2008, 02:40 PM
As a lube, WD40 or kerosene. Kerosene is cheap and works very good. I use the highest reasonable speed I can and feed moderately. If machined dry the chips will bond to the cutter and are hard to remove plus, it seems to dull the endmill some. I think a mister would work but haven't tried it.

ckelloug
12-28-2008, 03:25 PM
I remember the heady smell of A9 as my dad tapped CB antenna brackets in the basement. It smells kind nice and works well. Don't know how well it works in comparison to all the other home remedies however.

Scishopguy
12-28-2008, 07:28 PM
If you have nothing else, Kerosene does the trick. I worked for a cheap a$$ outfit that would not buy frivilous items like cutting oils or a full set of drills for the prototype shop. One cold winter day, while milling a short run of aluminum parts, I sneaked out to the fuel oil tank, took the line loose, and snitched about a quart of kerosene. Worked like a champ on the parts but the air bubble I put in the line killed the heater in the front office. All the engineers, who hated to be out in the unheated shop got chills and had to go home.

BMSS
12-28-2008, 09:31 PM
I cast a lot of aluminum parts, and I get all kinds of aluminum scrap to reuse. The stuff I like best is old engine pistons, and engine heads. They seem to machine as well as 6061 alluminum. Sometimes you find that no matter what you try to help the machining, WD-40, kerosene or whatever, the quality of the aluminum is so poor that just won't cut cleanly, and the finish will be terrible. If you are trying to machine some of this low quality stuff, all I can tell you is good luck.
Bob;)

aboard_epsilon
12-28-2008, 09:52 PM
if you are cutting a channel/slot in aluminium use a blow gun to blow out chips as they happen..........back it out and blow, if they get too bad

take it in stages don't do the whole depth in one go.

cut with a smaller end mill than the finished slot size.........then graze up the sides for a perfect finish.

use cutting oil like rocal and squirt small quantities at the slotmill flutes with pump oil can every 20 secs or so.

all the best.markj

Spin Doctor
12-28-2008, 10:36 PM
And never, ever use solid carbide.

Uncle O
12-28-2008, 10:41 PM
And never, ever use solid carbide.


???????????

I use solid carbide all the time if I have right size for the job, with no issues.
What is your reason for not recomending ?

JoeFin
12-28-2008, 10:57 PM
Blow Guns seem like a good idea until you have a problem with your mill only to find out there is a bunch of Al. chip all galled up in the ways.

Vacuum is the newer tech but quite pricey as the typical shop vac ain’t going to deliver the cfm needed to make a good show of it.

WD-40 seems like a winner too, but you need volume to wash the chips away to accomplish what you want

Hate to say it, but good Ol’ Flood Coolant has worked the best for me. My old Griz had the sump and pump in the base and was set up for Flood, but didn’t have the shields you find on most newer CNCs. I used to use card board, scraps of plexi-glass, what ever I could find to keep the stuff from flying all over me and the rest of the shop

You might as well get used to it now. Sooner or later you are going to need to cut some Cromemolly or other hardened steel and there ain’t no way your going to cut it without coolant

Spin Doctor
12-28-2008, 11:07 PM
???????????

I use solid carbide all the time if I have right size for the job, with no issues.
What is your reason for not recomending ?

As long as the coolant is flowing its fine, but aluminum will weld itself to carbide a lot faster than HSS. Been there, done that.

Your Old Dog
12-28-2008, 11:28 PM
I use WD40 and a 1" wide paint brush to clear the chips away. If I don't do the WD40 often enough the chips melt on the bit. Also, deeper cuts create more heat and chips which screws up the bits with weldment.

MickeyD
12-29-2008, 12:44 AM
I use carbide on aluminum a lot and normally run coolant, but I got some of the new variable helix 3 flute hyperlite carbide mills from exkenna/Curtis at latheinserts.com and they cut fine with no coolant. I was running them at 8000RPM and pretty aggressive feed rates and I got no chip welding at all on 6061, only turned on the coolant at the end of the part to clear some of the chips off to switch parts (it has been in the machine for 18 months and is foaming like crazy and needs to be changed). I am not sure what the hyperlite coating is, but they feel oily even when they are clean and dry, it is the slickest coating that I have seen. Most of the chip welding problems that I have had in the past have been with cheap chinese endmills, good name brand HSS and carbide (coated or not) seem to have a better finish that resists chip welding. There are some things that you can go cheap on, but endmills are not one of them.

macona
12-29-2008, 01:09 AM
I have had aluminum plug up a 1/2" variable flute from Lake Shore Carbide. Main reason I was moving faster than the chips could get out of the way. Got some air mist on it with a new end mill and never had another problem. I had to soak the other end mill in Zep purple for a week to get the aluminum off. Funny, the zep turns blue after a week.

Carld
12-29-2008, 10:51 AM
house hold lye in water will remove aluminum from steel over night. At least it does for me.

Oldbrock
12-29-2008, 01:52 PM
That A9 is made by Relton just for everyone's info and it is the very best cutting oil I have found for Al. No connection to the company by the way, just have found it to be the best. No need to flood, just apply with brush. :D Peter

bobw53
12-29-2008, 04:39 PM
I use carbide on aluminum a lot and normally run coolant, but I got some of the new variable helix 3 flute hyperlite carbide mills from exkenna/Curtis at latheinserts.com and they cut fine with no coolant...... I am not sure what the hyperlite coating is, but they feel oily even when they are clean and dry, it is the slickest coating that I have seen.

I got some of those, never tried running them dry though, but they sure are the prettiest coating I've ever seen on a tool, it was almost a shame to use them.

ExKenna (curtis) had video on the other board running dry in Al with an indexable cutter, absolutely hauling ass, very impressive.

Back to the sticking on the endmill. Are you taking a big enough chip, or just babying it along and rubbing more than cutting. I would slow the spindle speed down (which keeps the heat down) and keep feeding how you where. You can take an absolutely massive chipload in Al.

Just for fun a few years ago, seeing how fast I could eat aluminum on a Mazak. 708 ipm max feed of the machine, .375 wide, .375 deep, started at 12000 rpms, max feed, .015 per tooth(4 flt rougher, I know not supposed to do that, but I was just playing). Kept backing off the spindle speed and got to 7000 rpms(before I didn't like the sound) and the same 708ipm, just to see what kind of chipload it could take, a little over .025 per tooth with little flute clearance(really good coolant pressure). I've read in some trade rags of 1/2" single flutes, taking .060 per rev/flute.

derekm
12-29-2008, 05:38 PM
....

Hate to say it, but good Olí Flood Coolant has worked the best for me. My old Griz had the sump and pump in the base and was set up for Flood, but didnít have the shields you find on most newer CNCs. I used to use card board, scraps of plexi-glass, what ever I could find to keep the stuff from flying all over me and the rest of the shop

You might as well get used to it now. Sooner or later you are going to need to cut some Cromemolly or other hardened steel and there ainít no way your going to cut it without coolant

I endorse this message

Derek - A flood coolant sort of guy

Rich Carlstedt
12-29-2008, 06:07 PM
Having the right cutter helps, and so does good Aluminum like 7075.
But now is the time to grab those old Christmas candles and get some good use out of them.
Take a candle and let the cutter rub on it to pick up some pariffin.
And also rub some in the groove you are cutting.
the chips will not stick to the cutter, and you have sort of a solid cutting fluid, so no mess is created. the chips lump together.

It also helps to keep some candles by the cutoff saw.
They work great keeping the teeth from clogging as well

Rich

Watch the fingers !....use long candles

Phil McCrackin
12-30-2008, 09:57 AM
Thanks for all the replies fellas.


I use WD40 and a 1" wide paint brush to clear the chips away. If I don't do the WD40 often enough the chips melt on the bit. Also, deeper cuts create more heat and chips which screws up the bits with weldment.

This seems to work the best for me too. Although I am considering a flood coolant system, just because I a am lazy:)

Will using roughing bits at first, work any better?

Evan
12-30-2008, 10:23 AM
I use a generic version of WD40 that is sold by Canadian Tire stores. It works just as well as WD40 but doesn't have any perfume added. It's very nearly odorless and colorless. It's also cheaper.

BTW, I use solid carbide all the time on the lathe and don't have chip welding problems, even when dry.

jkilroy
12-30-2008, 10:31 AM
Kero works as well as WD-40 and is a lot cheaper, doesn't come in the handy spray bottle nor does it smell as nice but I don't feel bad about soaking down the cut with it.

Phil McCrackin
12-30-2008, 11:10 AM
The only problem I have with kerosene is that my shop is in my basement, so odor is a concern.

Evan, what is the name of the coolant you use. I live near Detroit and have fairly easy access to Canada (at least until the new passport regulations come into effect)

Also does anyone know of other brands that I can get in the U.S.?

derekm
12-30-2008, 12:00 PM
Heptane C7H16 is a relatively odourless cleaning alternative to kerosene, however it is much more flammable. Its the same stuff as Coleman fuel sold in Europe as L'Essence a nettoyer or Wasbenzine can be bought in small 1 L quantities (in Supermarkets) to 200L barrels. It can have less aromatic crap in it compared to white spirit /Stoddard solvent.
Works well in your SVEA 123 campstove.

Evan
12-30-2008, 05:51 PM
The product I use is MotoMaster Multi-Purpose Lube SKU 38-1525-8

It's $3.25 per can CAD as compared to $3.95 for WD40. Even the smoke on really hot turnings doesn't stink and it hasn't burst into flame yet either even on red hot swarf. It works well for turning ferrous also. It also keeps my wife happy as she can't stand the odor of WD40 any more.



Heptane C7H16 is a relatively odourless cleaning alternative to kerosene, however it is much more flammable.

That qualifies for an understatement award. That is much to flammable to use in a shop situation. The flash point is 25 F which means it will produce explosive vapours even at freezing. WD40 and the C Tire product are mainly composed of Stoddard solvent and light mineral oil with a flash point well over 100 degrees F. That means they cannot form an explosive mixture in air in any reasonable shop conditions.

derekm
12-30-2008, 06:50 PM
The product I use is MotoMaster Multi-Purpose Lube SKU 38-1525-8

It's $3.25 per can CAD as compared to $3.95 for WD40. Even the smoke on really hot turnings doesn't stink and it hasn't burst into flame yet either even on red hot swarf. It works well for turning ferrous also. It also keeps my wife happy as she can't stand the odor of WD40 any more.

....


That qualifies for an understatement award. That is much to flammable to use in a shop situation. The flash point is 25 F which means it will produce explosive vapours even at freezing. WD40 and the C Tire product are mainly composed of Stoddard solvent and light mineral oil with a flash point well over 100 degrees F. That means they cannot form an explosive mixture in air in any reasonable shop conditions.


I dont think its that different given the circumstances of the application...

heptane has Flash point: -1 C
Explosion limits: 1.1 - 7%
Autoignition temperature: 222 C

sold in supermarkets as a stain remover.

Stoddard solvent has various flash points from 21-55C
but it has an autoigntion temperature 240C. Stoddard solvent is mainly C7 to C12 hydrocarbons... and so it has heptanes in it

As a cutting fluid it is involved with temperatures well in excess of 100C which can be easily generated as you have said.

There are odourless kerosenes available which have higher flashpoints but
similar ignition temperatures.

Me? I use a water based flood coolant that is suiltable for Alu, Fe and Cu alloys and its very, very, very hard to set light. I dont like using wd40 and if I do I make sure there is enough to keep the cutter cool.

see

http://en.wikipedia.org/wiki/White_spirit

http://en.wikipedia.org/wiki/Flash_point

http://msds.chem.ox.ac.uk/HE/heptane.html

http://msds.chem.ox.ac.uk/WH/white_spirits.html

http://www.wd40.co.uk/media/adobe/2/0/WD-40_aerosol_MSDS.pdf

http://www.wd40.co.uk/media/adobe/a/t/WD-40_bulk_MSDS.pdf
...