Design Help

Design Help

File Resolution

STL format has become the standard for rapid prototyping, manufacturing, 3D Printing and even traditional processes. 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 part produced. The recommended facet resolution is 0.002” to 0.005”. Resolution set lower may lead to a part that is facetted or blocky and higher resolution may increase the size of the file without increasing the quality of the part.

Angle Tolerance

Angle tolerance sets the facet resolution for radii. 5 to 10 degrees is the recommended range. Going outside of this range may affect part quality or result in issues similar to the ones describes under file resolution.

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 rapid prototyping or manufacturing process. If you think there is a weak spot in your geometry, chances are it is vulnerable. The table below shows the minimum feature size for each process:

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, or build a part that is very brittle and prone to warp or break.

Tolerance & Assembly Clearance

Many parts are created as a component of an assembly of parts. Rapid Technologies build parts that are ideal for validating the form, fit and function of assemblies. It is critical, however, to account for the tolerances of the specific process when considering the amount of clearance to add to the design.

Special Features - Floating Components

Creating designs with “floating” features can be tricky. Make sure everything that should be connected is securely attached; otherwise it may build separately or break during cleaning. Try reducing your STL models to one shell, as multiple shells typically indicate “floating” or separated surfaces.

Material Properties

When choosing a rapid or traditional manufacturing process for your part, keep the material properties in mind. In some instances you may be able to produce your part with various technologies but significantly reduce weight or improve surface finish. In other instances you may only be able to get a particular material property with a specific material or technology. For example, if you require clarity, SLS can not provide this property.

Build volume & size limitations

After you determine your ideal technology or material for your application, review build volume and size limitations of the System. If your part requirement exceeds the build volume, you may need to cut or split your file and assemble it after production.

STL file quality

The quality of your stl file will determine the quality of the part produced. Make sure your stl file is complete and tight. Some stl files that are of low quality may not even be buildable. See our stl file guide for best stil file results.

Trapped raw material

If you design a part that has a closed component, consider that rapid technologies build layer by layer and will therefore trap powder, resin or other material inside. This will not only add to your part weight but may also impact the performance and usability of your part. In some instances you may need to drill a hole to drain the material. If possible, consider designing a hole into your closed component for easy raw material removal.

Finishing

If you require a secondary process to your part, such as painting, plating, and so on, you should evaluate the technology and material specifications to ensure best part quality for your chosen after production finish. SLA for example, produces accurate parts with very smooth surface finishes, ideal for numerous finishing processes.