accurately printable dimensions

Discussion in 'Technologies and Hardware' started by Monguse, Dec 22, 2011.

  1. Monguse
    Monguse New Member
    I'm a first-time designer on a steep learning curve with Rhino 3d 4.0 . Shapeways is in the offing for my prototype.

    The model I'm designing in Rhino has a few oddball dimensions i.e. 13.28 mm. or 7.09mm.

    Can the 3d printing process render these fractional dimensions accurately? What is the thickness of one deposited layer in the 3d printing process using the Ultra Detail materials option?

    How flexible is the Ultra Detail UV Curable Acrylic Plastic? Could it be used for an annular circular snap fit (like a child-proof aspirin bottle? Would it also be suitable as both the male and female bushing/bearing part of an occasionally slowly rotating cylinder? Or would other materials be better for either application?

    Some of the tolerances between the moving parts (bearing bushing) are fractions of a millimeter ( less than .2mm). I intend to have the parts printed separately without sprues.

    What is the best file format for 3d printing? Rhino offers many "save as" options.

    Thanks in advance for any help.

  2. stop4stuff
    stop4stuff Well-Known Member
    Hi Jay.

    Welcome to Shapeways! :)

    Frosted Detail (FD) & Frosted Ultra Detail (FUD) are printed using a Projet 3000 HD printer, the full technical spec can be found here (904k pdf), the accuracy is pretty fine.

    Being acrylic, FUD is fairly brittle so I wouldn't recomment it for parts that might need flexing as it may break the first or second time it was flexed. White Strong & Flexible (WSF) might be a better choice, but the print tolerances are nowhere near as fine as FUD.

    As a bushing lubricated with some PTFE/silicone oil I should think that FUD would be ok as long as the mesh making up the shapes has polys in the region of 0.05-0.1mm - my experience is that bigger polys leaves the printer to approximate the surface resulting in stepping.

    FUD can be printed as a multipart model, but depending on the geometry spacing between parts, the parts may need to be 0.15 to 0.2mm (or more) for the support wax to melt out.

    I've no experience with Rhino, perhaps someone else can jump in on that.

  3. Monguse
    Monguse New Member
    Thanks, Paul,
    I appreciate the information. Sounds like the more flexible material would be good for an annular snap fit and the FUD would be best for the bearing/bushing.