[lm6769]

I want to machine aluminum, I willbe making at least 1/4" deep pockets. I will be dry machining, (my machine is not set up for lub) So my questions are as follows

1) Which grade of alum. is best for dry machining?
2) Best please to buy alum stock? (I found this site https://www.onlinemetals.com/merchan...p=2&top_cat=60)
3) I will be using a 1/8" bit as well as a V point bit to be doing my pocketing. and I guess a 1/4" to do the remainder of the cuts. Which router bits have you found to be successful?

Thanks in advance. Mike

[LeeWay]

I haven't milled much without coolant. Stay away from 5000 series stuff.
Quite gummy.
I try to buy all 6000 series stuff. It is generally good and strong and quite machinable. 6061 and 6063 is what I have used the most.

Online metals is okay. A little pricey sometimes, but decent.
I get most of my stuff from Speedy metals or Yarde metals Drop zone.

[lm6769]

I haven't milled much without coolant. Stay away from 5000 series stuff.
Quite gummy.
I try to buy all 6000 series stuff. It is generally good and strong and quite machinable. 6061 and 6063 is what I have used the most.

Online metals is okay. A little pricey sometimes, but decent.
I get most of my stuff from Speedy metals or Yarde metals Drop zone.

actually for what Im looking for Online Metals seems to be 10 cheaper than the other sites.

what about 2024 I was reading how its slightly harder and may chip off betten than the 6061. but I guess for what Im doing I can use coolant. Ive read ATF transmission fluid is a good coolant to use. I wont be doing this often so I dont wanna buy expensive coolant. what type of router bits can I use. Ive been cutting a .025" aluminum using a 1/16" router bit and I get a decent finish out of it. Have yet to do pocketing with the bit though.

[lm6769]

2024 is way more expensive, I wont be going that route then

[neilw20]

Kerosene, Diesel, or JetA1 drainings - really low cost from your local airport, all work nice on AL.
Using a spray bottle limits the quantity to reasonably safe small amount.
Do keep a fire extinguisher handy - CO2 makes the least mess.
Only needs a small amount on the cutter to stop the AL sticking.
If you working in a cavity a little puddle will work for quite a long time.:devious:

[Bob La Londe]

Kerosene, Diesel, or JetA1 drainings - really low cost from your local airport, all work nice on AL.
Using a spray bottle limits the quantity to reasonably safe small amount.
Do keep a fire extinguisher handy - CO2 makes the least mess.
Only needs a small amount on the cutter to stop the AL sticking.
If you working in a cavity a little puddle will work for quite a long time.:devious:

I have much the same issues as the original poster, but I wonder about coolants. I have not setup a coolant / cutting fluid system yet, but plan to. The manufacturer of my mill says I can not use a water based coolant. This leads me to my questions. Kerosene, Diesel, WD40, or ATF are all over the counter easy to get locally. Diesel probably being the cheapest. (I have a tank out back for my tractor.)

Given your comments about fire extinguishers (I have 4 out in the shop) how would you suggest dealing with extremely long jobs? One job I have worked out with my CAM system and Mach 3 estimates out at about 30 hours to cut. Its a small part, but lots of detail. I do not want to set in front of the bench for 30 hours watching the machine make cuts almost to small to see.

I considered dry cutting the part, but I highly doubt the end mill would last that long without coolant. Not sure it will last that long with.

As far as my coolant system. I am building a low pressure air system so I can make the pressure tank and recovery tank any size I need to in order to manage coolant for reasonabley long time periods.

Basically I am at that stepping up stage. That stage where I need to be able to plug my system into a UPS and let it run for a day and a half. Lots of things to do before I can run some of those jobs.

I am also trying to figure out how to calculate speed and feed rates more efficiently. Might cut the time of some of those jobs down substantially, but that is a whole different topic, and I'll be posting it seperately. I've been figuring it out by guess and by SNAP so far.

[CMJacked]

Spray mister's They work for any medium and keep chips cleared as well.

[Bob La Londe]

Spray mister's They work for any medium and keep chips cleared as well.

And would create a more flash likely environement with any of the liquids mentioned.

[CMJacked]

Very good point, Personally I don't understand why you wouldn't use a good water soluble coolant in the first place. Spray misters work well for that if your in a situation where flood coolant is not possible. I've never ran across many CNC machines without it. Retrofitted machines not included in that statement. Solvents as mentioned above work well but not by design. If your setting up a CNC machine then set it up completely. Get coolant to your tools. Buy end mills designed specifically for aluminum, Smelling solvents all day long has got to have it's own hazards. So by all means don't use a spray mister with jet fuel..

[Bob La Londe]

Very good point, Personally I don't understand why you wouldn't use a good water soluble coolant in the first place. Spray misters work well for that if your in a situation where flood coolant is not possible. I've never ran across many CNC machines without it. Retrofitted machines not included in that statement. Solvents as mentioned above work well but not by design. If your setting up a CNC machine then set it up completely. Get coolant to your tools. Buy end mills designed specifically for aluminum, Smelling solvents all day long has got to have it's own hazards. So by all means don't use a spray mister with jet fuel..

The manufacturer of my mill says I can not use a water based coolant.

The machine is steel and hard anodized aluminum. Galvanic corrosion would be the result. I specifically said I planned to setup a low pressure coolant system. Unless I let the pressure tank run low it will always be a fluid, not mist based delivery.

[lm6769]

ok so we have established coolant is good to have, but what about tooling???

[leggazoid]

2024 best to machine
2011 good
6061 ok, but a little gummy.

I have heard mineral oil or minerial spirits make a good cutting oil for aluminum. Never tried it.

There are a lot of very near dry, coolant dispensers that use air coolant mixture. Check these sites...
http://travers.com
http://use-enco.com
http://mscdirect.com
http://shoprutlandtool.com


Micro100 makes some single flute cutters for aluminum.

Type of spindle you use makes a big difference. People prefer Sherline or Taig spindle instead of router motor.