Printing and Reviewing the Results

Step 8: Printing and Reviewing the Results

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After you have tinkered, tested and refined your design, it’s time to export it to a format that most 3D Printing systems can work with.   OpenSCAD can produce the STL (stereolithography) format of your design, but you first have to use the Compile and Render (F6) command.

Normal design compiling is done with the Compile (F5) command and takes additional time with each program code change that you make. The F6 command takes even longer, but it generates the data that OpenSCAD requires to export the design as an STL formatted file.

Remember the $fn variable? During design, we set $fn to a low value (about 15 to 20) to speed up design rendering cycles.

But now that we want output that is as smooth as possible, we have to increase $fn to a higher number. If you don’t, the printed part might have big, chunky facets that not only look awful, but might even freeze or bind your sliding and rolling parts in place because of unplanned intersections in the geometry.

My computer rarely lets me use anything above $fn=89; on this particular design.

After Compiling and Rendering with F6 create the STL file by choosing   Menu > Design > Export as STL

After you export to an STL file its time to load it into a viewer to see how it looks.

Before you email or upload your STL file to have it printed, you should load it in a program like MiniMAGICS for analysis. What you are looking for is a property called water-tightness.

If your design has poorly aligned geometry that leaves gaps in what should be solid surfaces, it won’t be water-tight and the 3D Printer will usually refuse to attempt to print it. It’s easy to test if a model is water-tight with a program like MiniMAGICS, and it’s a time-saver if you can fix any problems before you send your design out for printing.

The Big Reveal. How did the 3D Printed Fingers turn out?

The thing that impressed me the most is that these fingers came out of the printer fully functional in one piece with no assembly required. No extra fasteners, no press fittings, no snap fittings. They rotated exactly as planned and all the wire vias were clean and clear of any support material.

Nice.