Shapeways - low cost 3D printing site

[frank2056]

I have an account at Shapeways and I get a few free invites. They'll print from a 3D stl file into a variety of materials and they ship worldwide.

Their prices are pretty good, although they have a limitation on fine details (the smallest has to be 0.5mm or larger) and they're not the quickest shippers (7 - 10 days) but they have a really good selection of printers and it's a good place to start if you want to get into 3D printers.

I have a few invites (don't know how many) so email me if you want one.

Frank

[Jeffry Fontaine]

Hi Frank,

This is great news but I have to ask the question so you can clarify it for the rest of us.  What kind of data file is required to generate the 3D product?  This is critical to the process. 

[Hobbes]

The file format is called STL, this can be generated from many 3D CAD and modeling applications. The Shapeways site has more information on what's involved.

[frank2056]

Converting a 3D object into an STL file isn't too difficult; some 3D printing places will do the conversion for you. The hard part - the really hard part is getting the original mesh to pass muster. The Shapeways FAQ lists the requirements pretty well - basically, the object has to be "water tight" and have a thickness. Sometimes, your meshes may be missing a polygon or two, or form physically impossible objects (a stray polygon hanging off the model hay have a height and width, but no thickness).

There is software to check your meshes. Rhino3D has a built-in mesh checker that catches most (but not all) of the problems, and it has tools to fix them. What I do is use two separate programs to read in the .stl file and look for problems. The first is MiniMagics a free stl file viewer. It'll tell you that your mesh has problems (and color the problem bright red) but won't help you in fixing it - for that they want a lot of money.

I also use Meshlab, a free program that can be used to convert from the more common 3D file formats into STL and back. It will also allow you to fix the meshes (to a degree).

A third, non-free (but inexpensive) program that I like to use is AC3D. It's a pretty good 3D editor and can export as .stl (ascii only). It's handy for finding and fixing really recalcitrant polygons.

Even after you have your stl file clean and ready to go, you have to read the fine print for the 3D printer you choose - make sure that you don't have any details that are below the minimum resolution of the printer, or they just won't print properly, and make sure that your object isn't too big for the printer. Some printers have a surprisingly small work area - I was trying to print a model that was only 145mm across (5.75") and it was far too big for one of the printers.
Also, you have to keep the part thickness in mind. Since the price is based on volume, you want to avoid big solid parts. OTOH, you don't want a paper thin part; not only will it be very delicate, it may collapse or deform while in the printer!

Finally, depending on the printer resolution and material, your part - even if perfectly printed - will have lines in it from the printing process. Removing them can be either very simple (for the higher resolution printers) or very tedious.

Frank