How to Generate a Good STL File

The .STL file format has become the standard data transmission method for the Rapid Prototyping industry, and is the preferred format required to build SLS parts.

This format approximates the surfaces of a solid model with triangles. For a simple model such as the box shown in figure 1, its surfaces can be approximated with twelve triangles, as shown in figure 2. The more complex the surface, the more triangles produced, as shown in figure 3.

 

Almost all of today's CAD systems are capable of producing an STL file. For the user the process is often as simple as selecting File, Save As, STL.

Below are steps for producing high quality STL files from a number of today's leading CAD systems. In all cases, export your STL file as a Binary file. This saves on time and file size.

(Please note: these are only general guidelines and may not work or produce the best possible STL file in some cases. Please consult your user guide or the software developer for more information or technical support. Should we determine that your STL file is not adequate for production, we will contact you for an updated file.)

 

I-DEAS

1. File > Export > Rapid Prototype File > OK
2. Select the Part to be Prototyped
3. Select Prototype Device > SLA500.dat > OK
4. Set absolute facet deviation to 0.01
5. Select Binary > OK

 

ProEngineer

1. File > Save a Copy
2. Change extension to STL
3. Click OK.
4. Set chord height to 0. The field will be replaced by minimum acceptable value.
5. Set Angle Control to 0.5.
6. OK. Triangles will appear in the part to show the tolerance.

 

SolidWorks

1. File > Save As
2. Select STL
3. Click the Options tab (Optional)
4. Make sure that these settings are ticked: Binary, Unit are mm, Angle is 10deg. You can change the deviation as required. Normal is 0.01mm. Increasing this setting will either improve or reduce the quality of the output STL file.
5. OK. A preview may appear (depending on your settings)
6. Save

 

Unigraphics

1. File > Export > Rapid Prototyping
2. Set Output type to Binary
3. Set Triangle Tolerance to 0.0025
4. Set Adjacency Tolerance to 0.12
5. Set Auto Normal Gen to On
6. Set Normal Display to Off
7. Set Triangle Display to On

 

SolidEdge

1. File > Save As
2. Set Save As Type to STL
3. Options
4. Set Conversion Tolerance to 0.001 inches or 0.0254mm
5. Set Surface Plane Angle to 45.00º