I need to determine a machine cycle rate for a proposal we are giving a customer. It involves drilling lots of holes into thin gauge aluminum (nope not your project Brian). I need to determine the approximate time to drill each of these holes.

I'm sure it's based on diameter, speeds, thickness etc but could not find any formulas online.


Any suggestions?

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Sean Dotson, PE
RND Automation & Engineering
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How thin is the aluminum? You don't want to laser cut it instead of drilling?

What is the thickness of the aluminum, size of the holes and how many on what sort of pitch/spacing? Sounds like laser, water jet or a turret press might be the way to go.

Regards,

Anna Wood
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I Googled " drill feeds and speeds aluminum" and found this: http://www.chipblaster.com/Tech/SmallDr ... inumSM.htm

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Nick Hahn
Lornic Design

Specializing in pork harvesting equipment.

"The Standard Deviation of the Sampling Distribution of the Sample Mean ! " ( My wife's favorite statistics phrase! )

If there are to many hole, laser and waterjet will be too slow. The jet need to be turn on and off too many time.
I'll guess most of the cycle time is in positioning the drill. I'll punch the hole if possible. Drilling will leave big burr and need second operation to clean them.
A Trumph punch can do that fast without curling up the material.

The aluminum is a complex extrusion and cannot be laser or waterjetted. Furthermore we are drilling on three sides of the extrusion at the same time. Water jet or laser would be much slower.

Burrs are not an issue (it's a long story but they are not)

After posting I thoguht that perhaps the feed speed calcs and chip load forumlas in the Machinist handbook might be the answer.

Thanks for the input and links.

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Sean Dotson, PE
RND Automation & Engineering
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in aluminum if using carbide tipped drills you can get up into the rpm range
and it would take longer to get the drill to the surface of the part than it tould to drill thru it ,

give me your rpm , drill diameter and thickness as well as material spec
and i can give you some pretty accurate numbers .

you might also want to contact Joe at Autodrill.com he is a boundless source of multiheaded drill info .

basically it comes down to the drill bit and the speed you can run , aluminum is real gummy and tries to stick to the cutting edges , this is solved by using the right coated drill and sometimes pvd or cbn drill bits.

You do know Trumpf has rotary cutting laser design for pipe and tube cutting?

What it can do:

wont touch a multi sided drill set up for time though , with a laser your still popping them in one at a time

just a suggestion, but how about looking at actual drilling rigs and what performance they have.
each machine surely has a specific setting for each metal + thickness.

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Frans X LIebenberg
Structural Engineer
Cape Town, South Africa

Interesting. I had no idea. Thanks...

However I know this will be ou of their price range.

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Sean Dotson, PE
RND Automation & Engineering
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Funny,

Autodrill is who we were planning on using for the drill heads.

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Sean Dotson, PE
RND Automation & Engineering
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joe is the man


three biggest problems you will have are

chip/ cuttings , getting them out of the drilling are so the dont interfere with the drill heads or the next operation , clogging up the works so to speak

drilling the holes accurately , i.e drill walk off , this can be dealt with in many ways , really stubby drill bits , sharpened to a really thin web , guide bushings, and so on so forth , it would be foolish to make a reccomendation without knowing thickness , rpm and actual material spec , but i reckon your going to end up with a coated carbide high helix drill bit , maybe even three flute , to up the allowable feed per tooth .

and again material welding to the cutting edge will be a huge problem if not addressed up front , some aluminums are quite gummy .

let us know how it works out

Another source for speeds and feeds:

http://img401.imageshack.us/my.php?imag ... 001wx1.jpg

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-Russ