.0685mm to .0762mm I.D. hole 1

[Chancy07]

My company is considering a production job on a nozzel. The problem we are having is with the counter bore & the I.D. hole that is going through the counter bore. The material is with 303 ss. O.D. is 6.995mm. The conter bore is .250mm +/- .25mm , depth 2.25mm, with a circular runout of .025mm to the O.D. The I.D. is .0685mm to .0762mm, length is 1.250mm with a true position of .025mm to the O.D.
Any advice, suggestion, machine's capeable of doing this, or any names of companies that do this work would greatly be appreciated. Thank you in advance Brad

 

[MikeHalloran]

I'd guess you'll need a CNC Swiss-style automatic lathe to get the fine control to keep from breaking the drill.









Mike Halloran
Pembroke Pines, FL, USA

 

[Chancy07]

Thanks Mike,
Yes we already have a Swiss-style CNC and tried it on there, the problem is with the smaller I.D. hole wich is which is aprox .0025" to .003" in diameter. We have even tried sending the part outside to be lasered but they kept blowing the hole out on the top. Thank you for your input anyways.
Brad

 

[eromlignod]

How about carbon electrode EDM?

Don
Kansas City

 

[Chancy07]

Thanks Don will look into that today.
Brad

 

[MikeHalloran]

Hmmm ... yeah, that's a pretty small hole. I was kind of hoping that starting at the bottom of a (tiny) counterbore would allow the drill to flex a little with the spindle, but on reflection starting the drill is tricky and you probably just need a better spindle.

I had a male feature a little smaller than that made for a molded part once. I.e., a stepped pin, with the small part at .002" diameter. It had to be single pointed on a super- precision CNC machine kept in a temperature controlled room, and they had to let the spindle run for an hour to stabilize it, that sort of thing.



Mike Halloran
Pembroke Pines, FL, USA

 

[Chancy07]

Thanks Mike, I will mention that to our production manager.

 

[btrueblood]

Even EDM will be tricky at these diameters, you may end up with a tapered hole, with the result that holding tolerances will be trickier.

The counter bore is easy, just don't machine it at all, since the tolerance is 0.25mm +/- 0.25 mm (i.e. a 0mm hole is acceptable

National Jet Company, in Maryland, USA,

http://www.najet.com/

can do this job for you. They specialize in tiny, deep holes. Ask them for their business card, used to come with a hair taped to it, and the explanatory note that there was a wire threaded thru a hole drilled in the hair. You had to look under a scope to see the wire.

 

[Chancy07]

Sorry my mistake on the tolerance for the counter bore tolerance should have been .025mm. Thank you for catching that btrueblood. The problem we have with considering the edm is the life of the electrodes.
Thanks Brad

 

[MikeHalloran]

Yeah, those would be one-shot electrodes at best.

Try a different laser vendor. Some of them only have giant photon cannons, and can't do delicate work.



Mike Halloran
Pembroke Pines, FL, USA

 

[JimDavis]

what CNC swiss style machine do you have? adding an AIR or electric driven spindle (example NSK

http://www.nsk-nakanishi.co.jp/en/industrial/products/imf/ms_series.html

)

will hel;p with the small drill, as will making a "starter hole drill" to get the hole started straight, spinning the part the opposite direction of the drill whil spinning the drill will help "fool" the tool into not walking...

wither way it's one tough hole...

Electron beam hole drilling may be another option.

 

[unclesyd]

If you want mechanical drilling the afore mentioned NaJet is the route to go.

You may wnat to check out the following. I would give them a call.

http://www.smaltec.com/pathway.cfm