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ot FREAKING .010"-012" DRILLS 20XDIA

What are you using right now? I haven't gone quite that small, but I've had really good success with Mikron Crazy Drills
 
I used to use titex, they seemed less prone to wandering, the cheap drills never came out where they were supposed to, even then we had a sharpener with a microscope on, slight difference in land length was all that was needed to drill a curved hole, in 1/4” steel bar right through it was one shot, sub second per hole, thicker took peck drilling with flood on both, we had better luck when the stock was cool, outside in the sun bar stock was a drill killer, I put some in the freezer for a bit to chill, seemed like a mad enough idea, it worked, Hartley any burr on the backside, guessing ductile brittle transition myself.
Brass was the easiest, copper being a complete bsteward.
Main thing don’t cheap out on the drill and get the rep involved!, it’s free
Mark
 
We are using a little bit of variety, Kyocera, Hertel, and Harvey. Alum6061 and 1/2 hard brass materials, max rpm on machines is 10k. Normally run around 9500rpm with feeds from .0001"ipt to .0005" (larger .025-.035"). Like I said, we are managing, but every once in a while we seem to get a 'batch' of parts that we break multiple drills on. Not sure if bad material (we get mats from Alro), or faulty drills...?

Any tips? Can I feed them faster? I've just sort of stuck with what they were doing before me as I have never used tooling this small until this job.
 
Good morning Mike:
As you are no doubt aware from your experience as a toolbreaker, there are some things that are just a right royal PITA; no doubt about it.
This kind of problem will never be a doddle, you can always expect tool breakage, tool runout, work hardening and all the other shit we talk about regularly except with small holes even minor deviances from nominal have big consequences and you just can't control them all.

Harder batch of material...you're fucked.
Pick up a stray chip on a flute...you're fucked.
Coolant pump hesitates for a second...you're fucked.
Drill not perfect...you're fucked

Having said all that, I've drilled a fair number of small diameter long holes in my lifetime and I have found a few techniques that have helped me:

#1 is the quality of the spot drilled start.
I've always found that a spot that's just barely bigger than the drill is an absolute must, and it needs to be very clean or it will grab a flute and start the drilled hole off center.
So I use only brand new spot drills and chuck them always in a collet and check them for runout so they will make a cone shape that's as close to correct geometry as I can achieve.
The flat on the bottom of the cone needs to be smaller than the flat the drill will produce as it starts so the drill cannot walk sideways on the flat.

#2, is not to get greedy about the stickout of the first drill...make it short so it's stiff and gives you the best chance of a straight hole in the proper spot.

#3 is to program it so long drills will start in the hole at low RPM and then spin up to speed before they start actually cutting.
This is to avoid drill whip.
However I don't like to poke a drill down a hole without it turning...I've had munched up hole entrances that way if a flute catches on the way in.
Also I never pull the drill all the way out, I leave it in the hole 1X diameter and I try not to blast it with so much coolant that it deflects from the coolant pressure.
Sometimes I do better with my MQL system than with flood coolant, but it's a crap shoot.
Sometimes Rapidtap from a bottle, and a brush on the drill flutes to strip the chips is the only way through the job...if that is so, kiss your productivity goodbye and charge accordingly.

#4 is to keep the pecks modest.
This is controversial; many believe that a drill needs to be fed at least 1X diameter when pecking, but I have frequently pecked at 0.001" or even 0.0005" to get through a job that otherwise just would not drill.

#5 is to inspect every drill even brand new ones under the scope before you try using them.
Drill grinding technology is amazing, but every once in a while you get a dud, and if you start a hole with it, you are fucked for the rest of the hole.

After all that...I want a hole popper for my birthday.
0.012" holes 20 X diameter deep just cries out for this tech, and if you're doing any volume of these in conductive materials (that don't oxidize badly during hole popping like aluminum and titanium), the problems you will have to sort out will be much smaller and much more predictable.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining
 
Marcus, we do have a hole popper, but it is an "extra step" that they don't want if possible. Again, we are managing, just wondering about something I may not know about. We do peck .001-.002" depending on depth and diameter of drill. Nothing high volume, so if drilling takes 2-3 minutes or whatever not a deal breaker, just inquiring if there was something different I could try. :)

Plus one on inspecting every drill. Not thought of that, even though we have found 'new' endmills to have a chipped corner now and again...
 
Everything Marcus said.

It also really helps if you have an NSK with 40-80K RPM available.

I'm spoiled :D
 
Everything Marcus said.

It also really helps if you have an NSK with 40-80K RPM available.

I'm spoiled :D

I can't even imagine 40K rpm! :eek:

Also, for the record, .010-.012-.015 is about average for our small drilling. We do a few jobs with .005"x10dia. with only 10k rpm it's like watching paint dry LoL. Amazingly, those drills can be touched off on the Renishaw OTS on our older machines, but the newer machines break them. :confused:
 
I used to work for a machine building company doing exactly this. 0.008 to 0.125 EDM holes were our specialty. 20X depth no problem. Hardened alloy steel? No problem. Nickel-based superalloys entering at a near-tangent? No problem. Tolerance ±0.005 with Cpk > 1.67? We had to stay late a few weeks to get that one signed off, just cause that tolerance was in millimeters.

Ol' George hated when people called his machines "hole poppers" though, since they were all 5-axis microhole EDM drillers. Some even had an additional axis with a double living-hinge wire support to carve out a reverse taper hole; .010 on the inside, .008 on the outside (for example). Spent a long time calibrating those when they came in for rebuild. Pretty cool stuff, but a little too expensive for a birthday present, sorry Marcus.
 
I can't even imagine 40K rpm! :eek:

Also, for the record, .010-.012-.015 is about average for our small drilling. We do a few jobs with .005"x10dia. with only 10k rpm it's like watching paint dry LoL. Amazingly, those drills can be touched off on the Renishaw OTS on our older machines, but the newer machines break them. :confused:


Dude, if you're really doing holes that small regularly, your company is losing money by not purchasing an NSK or similar spindle.

You can get electric ones like this: http://www.nskamericacorp.com/product/category/HES510/14

Or the air driven ones, which can go through the tool changer: http://www.nskamericacorp.com/product/category/HPS/16

Note: I have no experience with either of these spindles, but I run A LOT of these: BM-319 | NSK America Corporation : Nakanishi Industrial and they make micromachining so much easier and faster.
 
Dude, if you're really doing holes that small regularly, your company is losing money by not purchasing an NSK or similar spindle.

You can get electric ones like this: http://www.nskamericacorp.com/product/category/HES510/14

Or the air driven ones, which can go through the tool changer: http://www.nskamericacorp.com/product/category/HPS/16

Note: I have no experience with either of these spindles, but I run A LOT of these: BM-319 | NSK America Corporation : Nakanishi Industrial and they make micromachining so much easier and faster.

Or, you can even get coolant driven ones, too.........

:soapbox:
 
Look up National Jet company: Tooling – National Jet Company

They can make you extra length specials - these guys figured out small hole drilling long ago.

Below is the machine that can allow anyone to drill a 0.001" hole with 5 minutes of training. It is a very clever machine that makes the drill bit the spindle, and is so sensitive that you can feel the flutes cutting. It also has a rapid acting pecking cycle that pecks at 0.0001" per peck. The machine below actually runs at 3000 rpm not 30,000 rpm. Run-out is the killer so you can not have any, then the speed makes way less difference.

Rare NAJET VEE DRILL 7M Ultra-Sensitive Precision MicroDrilling Machine 30K RPM | eBay
 
I couldn't resist this ebay buy, 10 carbide drills from .039" down to .0039" for $2.50, free shipping. The .0039" has a .120 length of cut, making it technically a 'deep hole' drill I guess. I looked at the tip of the smallest one under a microscope and it actually looked good. drills.jpg
 








 
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