[DroopyPawn]

Greetings.

I need to know what spindle rate and feed rate to use on a cut I'm about to try.

This is my first try at milling aluminum. I'm on a Taig 2019 which has spindle RPM rates from 1k to 10k. My aluminum is 6061 and is 0.25 thick. I'll be going in 0.08" passes on this first try - I think my machine can handle that.

The perimeter of the contour for the part is about 6 or 7 inches long. My carbide end mill is 1/8" diameter and has 4 flutes that are about 0.75" long.

So now that I've written the G-Code, what F speed should I add and what speed should I set my spindle to?

Thanks, gs

[DroopyPawn]

I tried it at 1k RPM and then about 2500 RPM and then 10K RPM. Each time, my end mill bogged down around the 3rd or 4th pass. I guess the 1/4 HP motor on my Taig is not strong enough. I started at 5 IPM which I guess was too slow. Then I tried 2 and 1 IPM. End mill still bogged down.

So is it the lack of motor power or what? I wouldn't think that 5 IPM would be too much at 0.1" depth cuts. Of course, I'm totally new at this.

[Ken_Shea]

gs,
RPM in aluminum if you keep the chips out of the way is usually not an issue, Definitely back off on the .1 DOC, try .030

Ken

EDIT:
If your mill uses a step pully for RPM changes try it at about 4K.

[DroopyPawn]

Thanks

Keep the chips out of the way.... Yeah, they seem to have welded to my endmill. It's round and smooth on the bottom now. Can I get them off?

What about the feed rate? How fast should I be trying to go, say at 0.030 DOC?

[CarbideBob]

Soak the endmill in muritiac or phosphoric acid (outdoors!).
The acid will dissolve the aluminum but not hurt the carbide.
Some toilet bowl cleaners also work.

Are you climb milling around the profile or slotting it out?

Bob

[LeeWay]

Consider spraying a little WD-40 on the part at various intervals. This will also help prevent the the aluminum Q-tip. I think depth of cut was your biggest hurdle.
When I work with a grade I haven't milled before or use a different type cutter, I like to start shallow. It is fairly easy to increase depth of cut later on if needed.

[DroopyPawn]

I'll try the acid. I'm climb milling around the shape but it has slots. It's sort of an "F" shape but with more than two arms. Flat/smooth on one side with arms/slots on the other side. Each slot is 1/8" wide. There's also one 3/8" hole in the middle.

Will WD-40 not gunk things up? Guess I'll try it again with the shallower cuts. Can I speed up the feed rate to around 12 for the shallow cuts with no problems?

[LeeWay]

WD will make some of the chips stay around, but a little more pray shoots them out of the tool path. It both lubes and slightly cools the mill, which is crucial if you are having sticking problems. WD is actually pretty clean and cleans as well as helps prevent rust. I use it on my router to mill aluminum often. I use stuff called cool tool on my manual mill. I will be adding flood coolant to my cnc mill project.
I little lube can really increase cut quality and tool longevity and stresses on your machine.

[Ken_Shea]

Can I speed up the feed rate to around 12

That should be a workable start Gary, it is most always a combination of what a particular mill can handle, this is even more evident the smaller they are. These seem to be a great little machine, one just has to operate them within their limits. This is true no matter what the size.

WD seems to be a very popular lube.
I do not know where you operate your mill but if you have a small air compressor, using a small low pressure air blast works well also to keep the chips out of the way.

Have you ordered those 3 flute carbide yet

[DroopyPawn]

I haven't ordered any 3-flute mills yet but I might. Looks like 4 flues makes it too hard to clear the chips. I am planning to add an air compressor to blow chips away. What about a couple of 2-flute 1/8" mills for this small stuff?

[Ken_Shea]

Absolutely, 1/8 2 flute will work just fine, the aluminum cutting 3 flute will just work better, you can cut faster and smoother, they are a win win situation, you can take that to the bank.

You can use 4 flute for profile milling just fine but they can and do, as you infer, clog easier when used for plunging, pockets or slots.

You will be amazed at the difference carbide has over even the hi-quality HSS cutters for general purpose machining.

Today there is less of a price difference then there used to be, especially in smaller size cutters.

Send me a PM with your address and I will send you a couple of the 2 flute 1/8" carbide, they will be better then the cheaper HSS that we all seem to own.

[DroopyPawn]

Wow, Ken. That seems extremely generous of you. I sent you a PM with my address. I'll go look for some 3-flute ones now. Got a few new end mills in the mail today.

A couple of 1/2" 4 flutes. Got one 1/4" with 6 flutes. And a few 1/4" with 4 flutes. Just trying to get my end mill collection up to par right now.

I guess I'll be using that 6-fluter on my CNC wood router project. It should cut the crap out of some maple shouldn't it?

[DroopyPawn]

Ok I found some 1/8" carbide with 3 flutes. Does this look right?
http://cgi.ebay.co.uk/1-8-2-3-4-FL-K...QQcmdZViewItem
$20 for 10 of them.

[Ken_Shea]

Well I was thinking more along these lines :;
http://www.lakeshorecarbide.com/inde...TS&Category=56

If you get the others check what you will be getting, they say abrasive carbide, may be burrs.

Afraid I cannot offer any advice on what may be best for wood.

[DroopyPawn]

That muriatic acid tip was certainly worth the cost. I figured it would take all night. My end mill was like new in 20 seconds. Thanks.

[CarbideBob]

One thing I should have mentioned. Store the muriatic acid far away from the machine and rinse the tool well with water before using.
The fumes make things rust real fast.
Bob

[DroopyPawn]

Those fumes are not very nice on the nose either, are they?!

[CarbideBob]

Those fumes are not very nice on the nose either, are they?!

Yea, I should of put this in caps. DO THIS OUTDOORS !
Even if there is 2 feet of snow on the ground and a snowstorm coming through I do this outside.
I use phosphoric acid which takes longer but its not so nasty.
Of course, store this stuff where no little ones can get into it.

Bob

[DroopyPawn]

Thanks for the useful tips. I actually got all the way through a small part today.

http://bb.steelguitarforum.com/userp...crank_12_1.jpg

Someone suggested using occasional squirts of WD-40 as a coolant so I tried it. Worked pretty well. I guess I'll be getting a little squirt bottle to keep some kind of coolant in. Will that stuff mess up my Taig's milling table?

What's the best way to dispose of the acid once I've removed the aluminum from my endmill? Should it go down the sink, onto the ground, into the neighbor's dog water bowl, into a jar, back into the 1 gallon plastic bottle?

[DroopyPawn]

While we're on the subject of acids, should I be concerned about getting this stuff on my hands? Or will it be okay if I wash it of with water a few seconds later?

Also, I melted some plastic onto an endmill the other day. Whats a good way to get THAT off? I ended up breaking it off with some pliers but I'm a little concerned for the health of my cutters using that method.