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How can I open up these holes they're too small

skoobiz

Aluminum
Joined
Jan 8, 2007
Location
Hagerstown MD
Okay so I received these parts from an old customer of mine. They had gotten a company to laser cut these to there specifications. When they received them some months later they were incorrect. The holes were undersized and tapered. They asked my brother if we could fix them and him being a salesman said sure we can do that we have a machine made for micro machining. Now these parts are extremely small 4mm X 1.8mm with a hole size of .15mm (see attached). There are about 50 of them to do and each one has 36 holes. Anybody have any tips on how to open them up. Oh I almost forgot one very important thing they are made out of Alumina (a type of ceramic).
 

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Hi skoobiz:
These are going to be a nightmare from hell to re-work on a number of fronts:
First, you're going to have to fixture them and locate the existing features.
Then you're going to have to find the ones that are too small...the photo's not very good, but they look all over the place to me, in size, in geometry and in location.
Next you're going to have to figure out how to interpolate them bigger with an 0.005" diamond pin...plan to spend a lot of money on pins and good luck sourcing them; the smallest I could find with a quick Google search is 0.015"
I don't think you're going to mill them with carbide...sintered alumina is harder than a woodpecker's lips.
If, by chance, you think they can be re-worked with laser, your problem is all about fixturing.

I'd dope slap my brother for blithely getting you into this mess, then I'd sit down with the customer and have a realistic conversation about reworking them vs tossing them in the scrapper and beginning again.
If these are cut with a laser from a large sheet, they can just lay the sheet down and put in all the holes, then walk around the outline faster than you can even handle the tiny bits to get them in the jig.

Sometimes, painful as it is, you just have to recognize when to run away screaming!

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining

On edit: You just might, with a LOT of patience, be able to hand lap them out with diamond coated wire like the kind used for precision wire sawing.
It goes down to 0.1mm.
However, you have 1800 holes to do under the microscope.
You'll be a gibbering loon long before the job is done, so if you commit to trying this CHARGE LOTS!
MC
 
Sounds like this one is your Brother's problem.

x2...................................

How much to just have them remade? Since every single part I send to customers is perfect:D...................I sometimes get asked to fix the other guys parts................doin' rework on someone else's parts?:wrong:.............................I make sure my price to do rework is very lucrative.....................or at least high enough where the customer says to just start over.
 
x2...................................

How much to just have them remade? Since every single part I send to customers is perfect:D...................I sometimes get asked to fix the other guys parts................doin' rework on someone else's parts?:wrong:.............................I make sure my price to do rework is very lucrative.....................or at least high enough where the customer says to just start over.

I had to rework a batch of 50 or so parts that wee done by another vendor. What a PITA! They were all over the place! In the mean time, we had taken over the job internally and my parts were always (we had internal cmm/QA that made sure of that) well within tolerance. And when I had a part go out a few thou it was always "nope! out of tolerance, no good", but theirs meh +/-.015" even tho print is +/-.005"... it's ok. :rolleyes5:

Anyways, had to build a little jig (not little like you have!), and probe every single part because they were so randomly out of spec there wasn't a reliable way to pick one part up and go... sorry nothing to offer, except what others said about scrapping them and making new, probably cheaper and faster.

Sounds like a job I wasked to do where it was a piece of clear tube? crystal? fiber optics of osme sorts? Anyways, material I had never cut, they wanted to cut little slivers off about 1/8" long and then put a 45deg bevel on one end, and polish it so it would show light thru it. Sure, I'll just stick that in my big ass UMC750 and have at it! :crazy:
 
We should at least be getting our money back on them. I'm pretty sure he told them time and materials instead of giving him a flat rate. The customer has been informed of the problems we are having and is supposed to be getting us some new material to try to do them from scratch. Which is pretty much what I expected. They are great people to work with, and we have known them for close to 40 years. So I'd really like to solve the problem they are having. Maybe it's time for me to get a laser so I can work with stuff like this. It makes for a good excuse for the bean counters anyway
 
I had to rework a batch of 50 or so parts that wee done by another vendor. What a PITA! They were all over the place! In the mean time, we had taken over the job internally and my parts were always (we had internal cmm/QA that made sure of that) well within tolerance. And when I had a part go out a few thou it was always "nope! out of tolerance, no good", but theirs meh +/-.015" even tho print is +/-.005"... it's ok. :rolleyes5:

Anyways, had to build a little jig (not little like you have!), and probe every single part because they were so randomly out of spec there wasn't a reliable way to pick one part up and go... sorry nothing to offer, except what others said about scrapping them and making new, probably cheaper and faster.

Sounds like a job I wasked to do where it was a piece of clear tube? crystal? fiber optics of osme sorts? Anyways, material I had never cut, they wanted to cut little slivers off about 1/8" long and then put a 45deg bevel on one end, and polish it so it would show light thru it. Sure, I'll just stick that in my big ass UMC750 and have at it! :crazy:

I'm pretty sure I have them convinced on remaking them from scratch. Now I just have to find a grinding pin small enough to do the job. Or like I said above use it for an excuse to get a laser. always wanted one anyway. Any suggestions on where to get the pins? or better yet who makes a really good femtosecond laser.
 
To open the holes at the present locations, a diamond charged thread could be pulled thru.

There would be a learning curve to arrive at the desired hole dimensions.
 
If you get a laser isn't it likely that you will have the same problem as the originals?

You mentioned the type of laser you want to buy, is it significantly better than the laser that was used for these parts? (which you didn't mention)
 
To open the holes at the present locations, a diamond charged thread could be pulled thru.

There would be a learning curve to arrive at the desired hole dimensions.

Almost my thought too, but I would use a .005" or so piano wire (if such a thing exists, hard stainless otherwise) and a diamond paste to suite (~8 or 10 micron). Put a short (1") section of wire in a sensitive drill chuck on a Bridgeport or good drill press.

After fitting wire into hole part way (to prevent whipping), spin at ~3K, tab diamond paste onto wire at junction with part, then pulse sensitive chuck up and down to lap the hole. Change wire as needed, adjust micron size of diamond ditto, blah blah. Bob's your uncle (or was before the realignment surgery).

Nice thing about this is that eye alignment by anyone with a bit of experience will be enough to keep the wire straight enough.
 
I don't have any suggestions, but I feel your pain. We've been working with a bunch of AlO PCBs, which need a fairly precise hole in them, and we're having them laser cut and they come out looking like garbage. But it's good enough for what we're doing. So far.
 
Almost my thought too, but I would use a .005" or so piano wire (if such a thing exists, hard stainless otherwise) and a diamond paste to suite (~8 or 10 micron). Put a short (1") section of wire in a sensitive drill chuck on a Bridgeport or good drill press.
Bridgeport ? Milland, shame shame ! You wrote '.005" wire' in that same sentence as Bridgeport ! That's the worst advice I've ever seen from you !

One of those little Electro-Mechano high speed benchtop precision drill presses might make the job tolerable. Might even work. Otherwise I'll go Milland one better and suggest a 4" Lucas boring mill :D
 
Bridgeport ? Milland, shame shame ! You wrote '.005" wire' in that same sentence as Bridgeport ! That's the worst advice I've ever seen from you !

One of those little Electro-Mechano high speed benchtop precision drill presses might make the job tolerable. Might even work. Otherwise I'll go Milland one better and suggest a 4" Lucas boring mill :D

I find your lack of faith disturbing...

But then, I find puppies and daffodils disturbing. In fact, now that I think of it, everything disturbs me! But no matter...

You don't want super speed here, you want fast enough to work, not so fast that the wire whips around out of control. 3K is a good starting point, may have to go up or down as needed but not to crazy levels.

I've drilled small holes (at an angle) in sheet sapphire in this manner, so take your pale retort and slink off!
 
How thick are the wafers? I see you can get Alumina down to .1mm. I'd be trying to convince the customer to go Macor so they could be made with regular drills, but it only goes to .5mm (from Goodfellow via brief googling). More fun to get the fancy laser and make Marcus jealous though.
 
I find puppies and daffodils disturbing.

Your wish is my command ...

View attachment 275943

Oops, those aren't daffodils ... what's that little white flower called ?

so take your pale retort and slink off!
Sigh. Another hard night's work in the reanimatorium ahead, then :(

260px-Re-Animator.jpg


p.s., just to be serious for a sec, I do think small machines for small stuff is a lot easier. I've done the 1" part in the 15" chuck before and it warn't much fun.
 
p.s., just to be serious for a sec, I do think small machines for small stuff is a lot easier. I've done the 1" part in the 15" chuck before and it warn't much fun.

Piffle. Bridgeports ARE small machines. Anything I can pick up and put in my pocket is small, and a BP qualifies. And I did mention using a sensitive chuck for the actual drive, did you not notice that? It has even more feel and less inertia than any small high speed drill press.
 








 
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