exporting 3d files for molding and 3d printing
Overview
Properly preparing a 3D CAD file is an important step in order to ensure your design data is the best it can be before sending to an injection molder or 3D printer.
3D CAD part files are created using design software such as SolidWorks, CATIA or Autodesk. The “native” design files are proprietary to the particular software maker and can’t be easily read by other software packages used to design molds or print parts. Therefore, “neutral” files must be created and exported for your injection molder.
3D Files for Molding
The most common neutral file format typically used for injection mold tool design is STEP (.stp). It is our top preference as well, but we can also use IGES (.igs) if necessary. Make sure to export as a solid and not surfaces.
3D Files for Printing
The defacto standard neutral file format for 3D printing is Stereolithography (.stl). 3D printer prep (slicer) software typically imports an STL file, applies printer and slicer settings as specified by the user, and then exports a GCODE file which is loaded into the printer in order to create the part with your injection molder.
This STL format basically approximates the surfaces of a solid model with triangles. The more complex a part becomes, the more triangles are required to duplicate the part model. And as a result, the more triangles, the larger the STL file. For most parts, STL files larger than 5MB are not necessary. Therefore, it is important to ensure the export options in your design software are properly tuned in order to get an accurate file without creating an enormous file. Below are general guidelines and suggestions for creating STL files depending on which design software is being used:
(Credit for STL saving instructions goes to 3D Systems)AutoCAD
Your design must be a three-dimensional solid object to output an STL file.
Make sure the model is in positive space
Set Facetres to 10
At the command prompt type STLOUT
Select Objects
Choose Y for Binary
Choose Filename
CadKey / KeyCreator
Choose Stereolithography from Export options
Enter the filename
Click OK
Geomagic Design (former Alibre)
File
Export
Save As >STL
Enter File Name
Save
I-DEAS
File >Export >Rapid Prototype File >OK
Select the Part to be Prototyped
Select Prototype Device >SLA500.dat >OK
Set absolute facet deviation to 0.000395
Select Binary >OK
Inventor
Save Copy As
Select STL
Choose Options >Set to High
Enter File Name
Save
IronCAD
Right Click on the part
Part Properties >Rendering
Set Facet Surface Smoothing to 150
File >Export
Choose .STL
Mechanical Desktop
Use the AMSTLOUT command to export your STL file.
The following command line options affect the quality of the STL and should be adjusted to produce an acceptable file.
Angular Tolerance – This command limits the angle between the normals of adjacent triangles.
The default setting is 15 degrees. Reducing the angle will increase the resolution of the STL file.
Aspect Ratio – This setting controls the Height/Width ratio of the facets. A setting of 1 would mean the height of a facet is no greater than its width. The default setting is 0, ignored.
Surface Tolerance – This setting controls the greatest distance between the edge of a facet and the actual geometry. A setting of 0.0000 causes this option to be ignored.
Vertex Spacing – This option controls the length of the edge of a facet. The default setting is 0.0000, ignored.
ProE
File >Save a Copy
Set type to STL
Set chord height to 0. The field will be replaced by minimum acceptable value.
Set Angle Control to 1
Choose File Name
OK
Rhino
File >Save As
Select File Type >STL
Enter a name for the STL file.
Save
Select Binary STL Files
SolidDesigner
File >External >Save STL
Select Binary mode
Select Part
Enter 0.001mm for Max Deviation Distance
Click OK
SolidEdge
File >Save As
Set Save As Type to STL
Options
Set Conversion Tolerance to 0.001in or 0.0254mm.
Set Surface Plane Angle to 45.00
Save
SolidWorks
File >Save As
Set Save As Type to STL
Options >Output As=Binary, Unit = Inches
Resolution > Custom, Deviation Tolerance = Minimum (Slide bar to right), Angle Tolerance = 5 degrees
OK
Save
Think3
File >Save As
Set Save As Type to STL
Save
Unigraphics
File >Export >Rapid Prototyping
Set Output type to Binary
Set Triangle Tolerance to 0.0025
Set Adjacency Tolerance to 0.12
Set Auto Normal Gen to On
Set Normal Display to Off
Set Triangle Display to On
