Surface smoothness when making metal items

Discussion in 'Technologies and Hardware' started by Eldamino47, Mar 14, 2012.

  1. Eldamino47
    Eldamino47 New Member
    I recently had two ring prototypes made up in the smooth white/polished material. I wanted to check the size/proportions and get an idea of how they'd look in "real life", then make up versions of each in metal after any needed changes, probably in polished stainless. Once they arrived I painted them silver. With the paint on I began to wonder if they were actually polished before being sent out, as there was some "grain" surface texture all over, and on the top and bottom and some of the angled or curved detailing there are clear irregular stepped sections visible, and some of the text and fine detail lines I have on the fronts is a bit muddled. On one of the rings that appears to be caused by me not making the text stick out enough, and I will correct it. The models seemed to look pretty smooth in the preview window, one more than the other, once they were uploaded (created in 3ds Max). I took one of the rings and worked over the surface with a Dremel and various sanding blocks then primed and repainted it, and it looks decent. I am new to this process, and would like to find out how closely the metal versions would correspond to what I received in the "polished white" material. I don't really have the facility here to do the same kind of sanding and polishing on something as hard as stainless, so would appreciate some details on how the process might differ, or if it will look exactly like the plastic versions, and if there's any recommendations for editing the models to guarantee a very smooth surface on curves or tapers. Thanks for any information, it is appreciated. It is great to have a company like yours where these things are possible, and your pricing is reasonable, I look forward to making more items.
  2. GlenG
    GlenG New Member
    The production polishing methods used on SS parts can not get deep into crevices and deep concave details so print lines will remain in those areas. Otherwise, all convex surface will be bright and close to mirror polish. Inside surface of rings will be smooth but some print lines will remain. If you have a Dremel, you can definitely improve the surfaces, it just takes more time and patience than finishing plastic.
  3. Eldamino47
    Eldamino47 New Member
    Thank you for that information. Where the print lines showed up on my rings are primarily convex surfaces. In areas such as the inside, or pretty much anything straight up and down the finish showed no lines whatsoever, it just had the fine grainy appearance once I painted it.

    On the one ring where I have text that is freestanding and somewhat deep set the graininess in those inset areas is fine, as I plan to put black in there, or if the Stainless is deep in color the grain contrast against the polished face of the letters will be great. I'm mostly concerned about the lines on the top and bottom, on one ring they were pretty minimal, but on the other, the design of which I like better, they were pretty apparent and irregular. I am beginning to think based on your description that the polishing part of my order may not have happened, I might have gotten them straight out of the printer.

    I've revised the ring model where the text wasn't deep enough and re-sized it a tad, will be doing the same to the other as well as seeing what I can do to make the top surface appear perfectly smooth in the preview and will order another set in polished white.

    For reference I'm including a photo of the ring where the printing lines on the top and bottom were the less visible of the two. I sanded the entire ring with three different sanding blocks, going from coarser to fine then hit it with some primer and sanded it again before spraying the silver. the grain on the surface is still pretty visible as is the print lines top and bottom. It almost has the appearance of being made out of very fine sand up close.

    I like the lines appearance here after the work I did to smooth them, I think they add a bit of cool detail but am concerned if I order the polished stainless steel or similar metal the surface and lines will be as rough as when I started on this one. The other ring required much more sanding to smooth out, I took it down to the point where no lines are visible as it has a curved design on the top and edges and the print lines were pretty irregular. So I'm trying to determine if the polished plastic versions finished surface appearance will correspond pretty closely to the metal version, or if the fact that the final is made from metal, and you heavily polish it, that it will have a nice smooth, solid looking exterior surface. The metal versions, while priced very well, are expensive enough that I'd just like to be sure before ordering.

    Attached Files:

  4. GlenG
    GlenG New Member
    A few things to consider,
    All additive manufacturing processes (3DP) leave surface
    , ie. print lines. Parts are built up as vertically stacked layers, so how the computer model is oriented at the beginning of the print cycle effects how the final surface will look.
    Several different machine systems are used in printing SW parts. The print resolutions (thickness of print layers) vary so you can not rely on results of one system to totaly predict results on another. Also the post processing (finishing) methods vary depending on your choice of media.
    Best bet for seeing what polished SS looks like would be to hunt the forum boards for finished rings from other Shapies.