Monthly Spotlight: Top 5 Design Tips

1. File Resolution:

STL format has become the standard for rapid prototype manufacturing. This format approximates the surface of a design using triangles. The resolution of the STL file plays an important role in the quality of the prototype produced. Due to the limitations of most prototyping processes the recommended facet resolution is 0.002“ to 0.005“. If you set the resolution much lower than this it can result in a part that is faceted or blocky. On the other hand, setting it any higher will dramatically increase the size of your file without increasing the quality of the prototype.

2. Angle Tolerance:

Angle tolerance sets the facet resolution for radii. 5 to 10 degrees is the recommended range. Going outside of this range will result in the same resolution issues described above. Smaller than 5 degrees results in a large file with no quality increase, and higher than 10 degrees can turn a round hole into a polygon.

3. Feature Size:

A feature is any prominent part or characteristic of a design that originates from the nominal wall. The recommended feature size is highly dependent on the prototyping process being used. The table below shows the minimum feature size for each process:

Process             Minimum Feature Size
SLA               Hi-Res – 0.010″ / Standard – 0.020″
SLS                         0.035″
FDM                        0.020″
PolyJet                    0.010″

4. Wall Thickness:

Wall thickness is a crucial dimension to consider. The minimum wall thickness for each process follows the same guidelines as feature size. A design with walls thinner than the recommended measurement may not build at all, and if it does build, the resulting prototype will be very brittle and prone to warp or break.

5. Tolerance & Assembly Clearance:

Many parts are created as a component of an assembly of parts. Rapid Prototypes are ideal for validating the fit and function of assemblies; however, you must account for the tolerances of the specific prototyping process when considering the amount of clearance to add to the design. You can reference the Tolerance Calculator application in the Learning Center portion of our website to determine the tolerances you can expect for your project.

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