Creating a good StereoLithography (STL) file with Pro/ENGINEER

• Good STL file creation is related to part accuracy and the overall physical size of the part.
• Default accuracy (0.0012) is usually satisfactory for parts that can be contained in a cube 100mm x 100mm x 100mm and which possess a smallest radii feature of R0.5 (ø1.0).
• If the part is physically larger in one dimension than 100mm and possesses small radii features, the part accuracy may have to be increased to produce a satisfactory STL file.
• It is best to do this prior or near to the start of the modelling process, when there are fewer features to regenerate.
• If this is not possible, a good STL file can still be produced but it is often a matter of trial and error, combined with experience.

Creating an STL file with Pro/ENGINEER

1. Select the FILE/EXPORT/MODEL/STL menu.
2. Use the defaults on the pop-up menu for Coordinate system, Binary format and allow negative values (ticked).
3. At the Chord Height prompt type 0.01 and press Enter.
4. If the Chord Height changes to a value of between:
            0.01 & 0.02, enter 0 as the Angle Control.
            0.02 & 0.04, enter 0.5 as the Angle Control.
            0.04 & 0.05, enter 1 as the Angle Control.
   
5. Click on OK.

Recommended Tolerance:
Ideally the Chord Height should be between 0.01mm and 0.02mm and the Angle Control set to 0. If the Chord Height cannot be set as low as this, a value of up to 0.05mm should be acceptable using the Angle Control values stated above. A Chord Height of more than 0.05 should be avoided as this would be outside of ARRK's tolerance.

Additional Information

Further information can be obtained from the Pro/ENGINEER Modelling User's Guide and the Interface Guide.

When transferring data to ARRK, include a copy of the .prt file with the STL file as the STL file may have to be recreated if the geometry is complex and cannot be produced in one piece, or if the part is larger than the vat on the StereoLithography machine.

This information has been compiled using ARRK's experience of StereoLithography and Pro/ENGINEER.

If you have any further questions please contact ARRK for advice on STL file creation using Pro/ENGINEER

Copyright © 2003 ARRK Product Development Group Ltd.