tumble polishing option?

Discussion in 'Finishing Techniques' started by LincolnK, Jul 18, 2010.

  1. LincolnK
    LincolnK New Member
    A local jewelry store that has cast some pieces of mine in silver (from traditional methods, not printed) has a machine that polishes pieces by vibrating in a bath of liquid and some small abrasive beads. Kind of like a rock tumbler but a bit different.

    It may take 12 or more hours for a piece to be polished using one of these, but it other than putting the pieces in and taking them out, there isn't much labor involved.

    I was wondering if SW has looked into getting one of these. I want to make small toys and jewelry, and would really like to see less pitting and stair stepping in the steel pieces. But, don't think it would be worth investing in a piece of equipment like that for just my own use.

    I would be willing to pay a bit extra for a piece that has gone through the process though. :)

    Although, rock tumblers can be purchased for under $50. Anyone ever try putting a printed SW piece in one of those?

  2. TomZ
    TomZ New Member
    I have some SLS parts that were tumble polished by another 3D printing supplier. It helps the surface finish a lot and it has even added a very slight shine to some areas.
    A problem with tumble polishing is that flimsy objects (as Shapeway's pricing encourages us to make) don't hold up very well. I would like for Shapeways to offer tumbling (for puzzle pieces) but it would need it to go hand in hand with a pricing model that makes thicker walls affordable.
  3. woody64
    woody64 Well-Known Member
    @TomZ & novaking

    Interesting, can you apply a picture to see what's possible.

  4. TomZ
    TomZ New Member
    I have my camera at hand but unfortunately 1000km of highway is separating me from the parts. So no, I can't give you any pictures at the moment.
  5. LincolnK
    LincolnK New Member
  6. GlenG
    GlenG New Member
    All Shapeways parts supplied with a shiny finish are finished by a "tumbling" process. The machine is known as a hi energy barrel finisher. Built something like a ferris wheel, this machine has several barrels that that rotate independently, as the central wheel rotates in the opposite direction. This dual action rotation creates an enormous amount of kinetic energy in the form of friction, and allows rapid processing of parts. Each barrel contains a different abrasive media. These media are graded to provide a range of effects from a coarse cut down to a very high final polish. Parts are cycled through each barrel until the desired effect is obtained. These machines are BIG noisy and expensive but can process hundreds of small parts at one time.

    The energy produced by these machines can destroy fine detail or even break some parts.
    This depends on your overall design. The forces at work in the barrel effect the high points and edges of a design most aggressively so these surfaces wear down more quickly than flat surfaces or depressions. Small thin projections, (like a tail on a mouse) are not likely to survive intact.

    Finishing any small part is tricky business. The SS print media is particularly tricky because when compared to other metals like bronze, aluminum or even simple steel it has an extremely hard surface and is also somewhat brittle. In truth, some parts will always need to be hand finished to achieve desired results.

    Last edited: Jul 23, 2010