Manufacturing a part with .004" wall thickness
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    Default Manufacturing a part with .004" wall thickness

    I have a component required for a small stirling engine we are building that we are having difficulty manufacturing due to a 0.004" wall thickness. It's about 4" long and has a max diameter of around 0.630". There is a zip of the PDF drawing attached.

    We have not had much luck getting this part quoted so we have put some effort into trying to get it made ourselves. We found that we can get the part made with all the right outer dimensions easily with just a blind hole drilled in the middle. Then we take that part and try to put the inner bore in via EDM but whenever we do this the thin wall section just disintegrates.

    We have also thought about encasing the part in solder prior to the EDM to see if maybe supporting the wall outside would help but he needs the OD exposed to line up to. We have also considered about leaving the OD large, finishing the ID via EDM or whatever, filling the part with solder, then grinding the OD to the correct wall thickness.

    3D printing is an option since we have access to one however it leaves a poor surface finish and we can't quite print thin enough so we still need to do something to finish it afterwards which leaves in the same situation.

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    Default .004 wall tubing

    Quote Originally Posted by dgoodell View Post
    I have a component required for a small stirling engine we are building that we are having difficulty manufacturing due to a 0.004" wall thickness. It's about 4" long and has a max diameter of around 0.630". There is a zip of the PDF drawing attached.

    We have not had much luck getting this part quoted so we have put some effort into trying to get it made ourselves. We found that we can get the part made with all the right outer dimensions easily with just a blind hole drilled in the middle. Then we take that part and try to put the inner bore in via EDM but whenever we do this the thin wall section just disintegrates.

    We have also thought about encasing the part in solder prior to the EDM to see if maybe supporting the wall outside would help but he needs the OD exposed to line up to. We have also considered about leaving the OD large, finishing the ID via EDM or whatever, filling the part with solder, then grinding the OD to the correct wall thickness.

    3D printing is an option since we have access to one however it leaves a poor surface finish and we can't quite print thin enough so we still need to do something to finish it afterwards which leaves in the same situation.
    You might try a supplier making hypodermic needles. Or try doing this with a plating process to grow the part on a mandrel, then polish OD. while still on the mandrel. If you know a purchasing agent or buyer, they can lead you in a direction for sources. Also the local public library is a source.
    All the best.
    Roger

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    Thank you for providing a complete drawing.

    What is the material?

    In general, when making thin wall tubes like this, the usual approach is swaging, so you might want to contact a specialist in that area.

    I think that carbon fiber structures can get this thin and might be stronger and stiffer than steel, but it would require a specialized mold and layup process.

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    Please keep this in your original thread.

    Machining Thin Wall SS Component (0.004", 100 micron wall)

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    I have machined thin wall stainless parts by machining the ID, filling it with a low temperature metal (filler for tube bending) and machining the OD - though my parts were smaller.
    Your part can be made out of a separate tube joined to the end parts. One process I was using for joining was high temperature (900°C) 22K gold solder. An alternative is EB welding. "Electron Beam Engineering" in Anaheim, CA were mot helpful in welding those parts for me.

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    Have a look at thisProducing Extremely Thin Wall Parts ---Made Easy - YouTube video. Don’t know if it will work with walls as thin as yours, but it would be easy to try. A very clever technique.

    Jon

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    Well, my first step would be to slap the engineer and tell him to stop being an idiot. If he insisted the part had to be machined that way, and was totally worth the cost, then I would start designing a collapsable mandrel to hold the part from the inside, probably a multiple wedge design, supplying more force in the thicker areas and just support in along the thin body.

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    Quote Originally Posted by crazygoat View Post
    Please keep this in your original thread.

    Machining Thin Wall SS Component (0.004", 100 micron wall)
    I apologize. It looks like I somehow accidentally posted this twice but the second post showed up later.

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    Your PDF is hard to read, but I am assuming that the center, tubular area is the thin wall area.

    Have you considered making the two ends and the center tube separately and soldering or brazing them together? That tube could be constructed from shim stock with a soldered or brazed seam. But then, you didn't say what the material is. Brass might make this easier.

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    They make seal savers with thinner walls than that out of Stainless, although not that long. Beer cans are made by the millions. Oil filter cans too. It's call deep drawing.
    JR

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    That's the catch - does the part really need to be that thin? It sounds more like a shitty design problem than a manufacturing problem.

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    Machine the reasonable-dimension end pieces, vacuum braze to a tube from these folks Thin wall precision tubes in stainless steel — Sandvik Materials Technology or maybe these Thin Wall Tubes - Bellows and Convoluting Industry


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