Drilling 6061-T6 aluminum without coolant ?

[mike_f]

Hi,

Is anyone succesfully drilling 6061 aluminum without coolant and if so can I ask what type of drills you are using ? I have to drill and thread mill (2000) M4 x 0.7 holes with a thread depth of 8mm in 6061-T6 and I have to keep the parts dry. I'm not too concerned with the thread milling aspect but quite honestly, I've talked to tooling "experts" from OSG, Guhring, and SGS and I'm not very confident in the information I've recieved.

I was hoping someone with real world experience might offer some insight.

 

This operation will be in a horizontal with a 15000 RPM spindle, I do not have thru the spindle air. If anyone is tapping aluminum dry that would be good but I figured that's a no go, so I'm assuming thread milling is the only option.

 

As always, I would greatly appreciate any insight you could share, thanks ahead of time.

 

regards,

Mike

[DAN 1313]

I would look into Emuge tools.

[mike_f]

Hi Dan,

Thanks for the reply. I looked at Emuge for taps and thread mills but they don't make drills ( to my knoledge ).. They do make a "thriller" , drill and thread mill combination tool but I would need thru the spindle air to run it dry in aluminum, not to mention it's $410. ( list ) which is a bit pricey for (2000) holes.

 

Mike

[DAN 1313]

its not a large hole possibly an air line off to the side of the spindle. sometimes you gatta do what you gatta do. i really think the cost of the tool is small considering all it can do. just my opinion.

[Rotary Ninja]

What about a dab of WD-40 on the drill with a small brush after every hole? Any drill would do fine then doing a deep hole peck and a fast feed. If WD-40 is ok, use a tap.

 

If you can't use WD-40 do a short peck with full retract and a fast feed. I would try around 1000 RPM and 15 IPM with a .075" peck to start. But you may be able to crank the feed even more. Aluminum is cheap. Run a test block.

[The_kid]

powedered metal parabolic flute.

[mike_f]

Thanks for the quick replies guys, I appreciate the suggestions.

 

Hi Ninja, nope, can't use anything, no coolant, no oil, no kerosene, I'm thinking my best bet right now is an OSG EX-SUS drill ( OSG series 1100 ). I use them in stainless steels mostly. And yes, aluminum is cheap, the problem is machine time to run a test, every machine in my shop is 3 weeks behind and then there is the value of the job, not much $$ in this one and we didn't find out we couldn't use coolant until after we quoted it and the parts were on our dock ( arghhh ), Of course we will be altering our quote but the owner wants me to see what we can do to keep it cheap. These are pre-existing parts that we are just adding two tapped holes to. It's kind of a "favor" to a big customer, I'm sure you all know how that goes.

 

Thanks for the suggestion Kid. Why powdered metal ? have you had success with these in aluminum running dry ?

[Guyinthedesert]

What about spraying some Drylube on the drill?

[RaiderX]

Have had great luck with these http://www.guhring.com/ProductsServices/Tools/?Type=W. will get the chip out fast and reduce galling. 6061 is a little gummy. somewhat lower RPM as mentioned will help keep you from a melt down.

[The_kid]

it's also going to come down to the coating! if it is sticking at all so the speed. The powedered metal seems to last longer then HSS I think because it is harder then HSS and the parabolic flute is great for chip evacuation. Haven't had to run it dry but always had great sucess with deep holes in alum without pecking. G73 chip break might be we suited as well. only way to find out is try

[mike_f]

thanks again everyone.

Yeah Kid, that's what it will come down to, giving something a try, luckily it's not a very deep hole only being 3.5 x D should help, it's the (2000) holes that disturb me. I don't think I've ever used something like drylube on a cutting tool Guy, but even if it was acceptible, I don't think I can stop to spray a drill every hole or two. I've used a lot Guhring products lazyboy but the linky you have is broken so I'm not sure which one you're pointing at. I think at this point it's going to be the OSG SUS drill and like the Kid says, only way to find out is try.

 

I'll try to post the results when we get it in the machine. thanks again everyone.

[GoetzInd]

Can't even use water or alcohol?

 

Mike

[The_kid]

Ok mike I think we're all curious why you can't use coolant. My guess is it is a rework job and has already been coated with like a CARC?? Oh btw I was thinking about your topic. guhring GT100 622 I couldn't find a powdered metal one. So I was wrong about that part. alum starts to melt at 1080F so a drill with a large web is going to create a lot of heat.

[Rotary Ninja]

I ran a government part one time that you couldn't run any coolant on simply because the material could not be contaminated. No special coatings or anything. Was a lot of fun.

[mike_f]

Good morning everyone,

Well Kid, I think my customer is just a knucklehead. I have a thousand pieces of what I believe is like a mic 6 tooling plate pre cut into 5 x 4 inch rectangles. It is a Japanese product with protective sheeting on the faces with the name "Kobelco" on the sheeting. I think it's just tooling plate. From what I understand it is a setting plane of some sort for a digital photography sensor and the surface finish is "critical". We are told that any kind of liquid contamination will cause "blotches" and or stains on the surfaces after they are plated. If the sheeting becomes wet at all, we have to remove the paper, clean the material with a chemical they supply and re-wrap the parts with what looks like glad wrap. We don't want to have to go through all this, so we're going to try to run it dry.

The kicker is that we were originally asked to bead blast the parts but they wanted a uniformity in the blasted surfaces that we can't maintain with our equiptment, so I'm sure these are being bead balasted after we handle them and before they are plated. Probably going to be chemically etched or run through an acid bath also.

 

In my opinion, this customer is just being "anal"... but of course I can't tell them that. I've already spent more time than is logical for a $2.00 part, but as long as my paycheck gets signed every week I just do as I'm told.

 

For all I know, these parts could be for the government Ninja, in which case they wouldn't be happy if they didn't cost ten times as much as they should.

 

Hope you all have a good day. I've got a couple weeks before these go in. I'll let you guys know how it went when I run them. Thanks again for the suggestions.

[GuyW]

Being Mic6, you'll have an easier time cutting dry than if it were 6061

[Thoob]

Thanks for the quick replies guys, I appreciate the suggestions.

 

Hi Ninja, nope, can't use anything, no coolant, no oil, no kerosene, I'm thinking my best bet right now is an OSG EX-SUS drill ( OSG series 1100 ). I use them in stainless steels mostly. And yes, aluminum is cheap, the problem is machine time to run a test, every machine in my shop is 3 weeks behind and then there is the value of the job, not much $$ in this one and we didn't find out we couldn't use coolant until after we quoted it and the parts were on our dock ( arghhh ),

 

If this was me, and there was no word of "not using coolant" in the quote as you mention, I would be upping the price based on that alone. You don't like it? Take your parts back. I think its stupid to take a job that you will lose money on. Not even worth the time to talk to customers like that. To me that is a key factor and should have been mentioned up front first thing.

As for machining dry like that with such a small hole, I say good luck. That will not be an easy feat.

[mike_f]

Hi Guy, No, it's 6061-T6, I just mentioned that it reminds me of mic 6 in how it's packaged.

 

Yeah Thoob... I agree 100% ... that's why they don't let me talk to customers anymore Like I said earlier, this is a big customer and the owner wants to do him a favor with this one.