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I am trying to fabricate a very small elliptical nozzle; if possible, 10um x 20um. I am almost certain that this cannot be achieved with regular machining. Ideally, the material would be corrosion resistant (e.g. stainless, brass) although that is not absolutely necessary.

The depth of the hole would depend on the material. I need to have small deflection with a pressure differential of 80kPa. Therefore, a stronger material like SS would maybe have 1-2mm of depth.

The tolerance is less important than the smoothness of the edges. A hole that is a couple of microns off spec is better than one that has edges with roughness of 1-2um.

Could it be done with laser cutting? Are there any other methods that could achieve such feature size? Thanks.

Edit: added material and tolerance requirements.

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  • $\begingroup$ Your question is missing details such as material, thickness, hardness, tolerance, etc. Hit the edit link or it's likely to be closed for lack of detail. $\endgroup$ – Transistor Apr 15 '20 at 10:49
  • $\begingroup$ The highest aspect ratio that I am aware of for laser-drilled holes is 25 µm in a 250 µm thick plate $\endgroup$ – OpticalResonator Apr 15 '20 at 13:46
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Do you need that for production at scale? If no, a focused ion beam could easily give you the accuracy you seem to need, but 2mm in depth maybe borderline...

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It's unlikely you'll be able to accomplish your goal. Lasers and high pressure water jets are not the tools for the smallest possible features.

Electrical Discharge Machining (EDM) is capable of fairly impressive performance, but even then, your objective is smaller than the "world's record:"

Engineers and scientists at Cardiff University are appearing in this year's edition of the Guinness World Records book for the smallest hole ever drilled -- at least with human-made tools. By using a process named 'electro-discharge machining' (EDM), they've drilled holes just 22 microns wide.

The above information is from 2006 and may be out of date.

Another option that has to be rejected would be photo chemical etching. From the linked site:

Chemical etching, or photo chemical machining, offers many advantages over other milling techniques may not be as accurate or economical. It:

Doesn’t introduce any sources of mechanical stress: Each part maintains the mechanical properties of the customer’s selected metal (or metal alloy).

Dissolves the unwanted metal via chemical reaction: burring, shearing deformation, and ablative deformation typically associated with other machining processes are avoidable.

Improves precision: Chemical etching can be used with materials as thin as .0003 inches. Holes can be as small as .004 inches, while edge dimensions can be within ±10% of a part’s thickness

I think one aspect of the above advantages to approach carefully is the plus or minus ten percent. A piece of stainless steel one to two millimeters thick could have a hole with 100 micron variation over its depth. A hole "as small as 0.004 inches" is 100 microns, far from your desired figure.

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  • $\begingroup$ In your experience, what would you say is the minimum size that could be achieved using readily available tools and processes? $\endgroup$ – supvato Apr 15 '20 at 14:52
  • $\begingroup$ Based on the research I've done, you will be limited to the smallest drill one can purchase. I was able to find a 100 micron carbide bit: eternaltools.com/carbide-micro-drills but the warning is valid. Careless handling will break the bit, as carbide is quite brittle. I would not use such a tool bit unless it was in a high precision CNC mill. $\endgroup$ – fred_dot_u Apr 15 '20 at 15:35

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