Drilling aluminum

[67 Yankee]

Looking at making thousands of .593"+/-.001" X 1.00" deep through holes in 6061-T6. So far we've just drilled and mill bored which produces a great finish and allows us to use an off the shelf tool for this odd sized hole, but it looks like we're going to be making many many thousands of these hoes now. Anyone know of a drill that can one-shot these holes, or other way to speed up the process while still producing clean accurate holes?

[Guest]

quote:

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which produces a great finish

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You were working to as you say "great finish"

 

What IS the finish requirement?

 

That is going to really determine what needs doing.

[67 Yankee]

quote:

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What IS the finish requirement?

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There's no requirement on the drawing, but we would like to stay around 32 microinches since these parts will be handled and we want the end user to feel that they have bought quality.

 

Also just by the way, some of these parts have been produced in China and we've been able to bring the quality and price in line well enough to grab some decent work. Now if we can gain a bit more ground we'll be able to get a bigger bite =)

[Columbo™]

Have you tried the Kennametal Dynapoint drills.

They have straight flute carbide drills that can hold tolerances and finishes.

 

 

try here

[crazy^millman]

How about a double margin drill. You might look at a inserted drill and a form reamer from Komet. They can ream that all day long and hold +/-.0002.

 

HTH

 

[ 01-09-2009, 01:08 PM: Message edited by: Crazy^Millman ]

[67 Yankee]

The double margin may be good. The straight flute drill scares me a bit on this material since I don't have coolant through the spindle, but then again we're going less than 2 diameters deep. Maybe it would be ok?

 

I want to avoid a reamer if possible since we have only two holes this size per part. I'm really interested in cutting out the tool change if possible. Right now I use one endmill to finish the outside of the part as well as the holes, but if I can drill finished holes that will still save me some time.

 

I'll see if my carbide sales guy has a supplier that can provide a custom sized double margin drill for this.

 

Thanks for the input!

[Tim Simmermon]

Maybe consider eliminating the drill all together and use the end mill to Helical interpolate to rough mill, then use the same cutter to finish.

[MLS]

3 flute dreamers in aluminum will hit that kind of tolerance. A tighter tolerance than that is iffy though.

 

I do NOT know that it would produce a 32 finish. IF you could get it tested and get that kind of finish it would smoke through them. They cruise pretty fast with no chip break necessary at a 1 inch depth if your spindle can handle the load of that diameter.

[Tony35]

quote:

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3 flute dreamers

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what are 3 flute dreamers?

dream bout making that hole and its all good?

 

J/K

[MLS]

3 flute carbide combination drill/reamers. There are a few places that make them, but they are certainly not wildly popular because if you don't run them at the proper speeds and feeds they really suck.

[Tony35]

do you need spindle thru coolant with those?

[Justin Beebe at Folsom Tool]

I have held +/-.001 in 6061 using Ghuring and Kenametal 3 flute carbide drills. I forget what they are called but they have a real sharp self centering point on the end. These drills hold location, size, and they cut fast. Call either company and tell them what you are trying to accomplish and they will get you the correct drill.

[FP1]

Wasn't the Kennametal 3 flute drill originally a Hertel T15 drill? Those were great for Aluminum.

(edited) But if I remember speeds and feeds were critical to good performance. Fairly heavy feed rates to get a good chip evacuation I think.

[Thad]

I'm almost positive the "dreamer" was the idea of a local guy. His name slips my mind at the moment.

 

Thad

[FP1]

Well Thad, you know what they say. "The mind is the second thing to go" .................... For the life of me I can't remember what the first thing is.

[Jaz]

I have had no problems with kenametal's dynapoint drills in this type of application. Go to your Kenametal rep and tell him what you want to do. If you have the quantities you can afford to have a custom one shot drill made, and if you do get a custom drill, you might consider adding a little chamfer to the drill for debur.