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The Rapid Prototyping Process uses .stl or
Stereolithography files to build physical 3D Cad Models. Stl files are created
using a mesh made from triangles to represent the physical part. Most CAD
programs allow an easy export of .stl files.
Tips on creating perfect .stl
files
Faceting, or flat spots on your part file are relative to the
resolution of the .stl file. A good .stl file size is between .5 meg for a
simple file to 10 megs for a large complicated part. Generally if your part is
outside of these parameters it should be resized.
Checking your .stl
file
Open the .stl file in your cad application and look at the
faceting to ensure the part appears as designed checking for excessive flat
spots on curves and contours. Also double check if your file is in inches or
millimeters, some programs such as SolidWorks export in millimeters even if the
drawing is in inches. Certain CAD applications do not open .stl files you can
download
Marcam
Viewer which will open .stl files for free.
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Resolution Too
Low
When the faceting is too coarse you can see flat spots on curved
surfaces. The flat spots in the .stl file will show up when the part is
produced.
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Resolution Too
High
while the parts will print when the resolution is too high, it
can cause delays in processing parts because of the large size. Increasing the
resolution excessively does not improve the quality of the produced part.
Please ensure your .stl files are under 10 megabytes.
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Perfect
Resolution
Good .stl files have faceting simular to the files
pictured on the left, and are manageable to work with and produce excellent
prototypes.
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Here are instructions to create .stl
files from Popular CAD applications.
Alibre
1. File
2.
Export
3. Save As > STL
4. Enter File Name
5. Save
Ashlar-Vellum
1. File > Export...
2. Select
STL Export Type
3. Set Export Options to Binary > OK
4. Enter
Filename
5. Save
AutoCAD
Your design must be a three-dimensional solid object to output an STL
file.
1. Make sure the model is in positive space
2. At the command
prompt type “FACETRES”
3. Set FACETRES BETWEEN 1 &10. (1
Being low resolution and 10 high resolution for STL Triangles).
4. Next, at
the command prompt type “STLOUT”
5. Select Objects
6.Choose
“Y” for Binary
7. Choose Filename
Autodesk
Inventor
1. Save Copy As
2. Select STL
3. Choose
Options > Set to High
4. Enter Filename
5. Save
CADKey
1. Choose Stereolithography from Export options
2. Enter Filename
3. Click OK
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 0.000395
5. Select Binary > OK
IronCAD
1. Right Click on the part
2. Part
Properties > Rendering
3. Set Facet Surface Smoothing to 150
4. File
> Export
5. Choose .STL
Mechanical
Desktop
1. Use the AMSTLOUT command to export your STL file.
2. 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.
A. setting of 1 would
mean the height of a facet is no greater than its width. The default setting is
0, ignored.
B. Aspect Ratio
- This setting controls the Height/Width ratio of the facets.
C. 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.
D. Vertex Spacing - This option controls
the length of the edge of a facet. The default setting is 0.0000, ignored.
ProE
1. File > Export > Model (or File > Save a Copy)
2. Set type to
STL
3. Set chord height to 0. The field will be replaced by minimum
acceptable value.
4. Set Angle Control to 1
5. Choose File Name
6. OK
ProE
Wildfire
1. File > Save a Copy > Model
2. Change type
to STL (*.stl)
3. Set Chord Height to 0. The field will be replaced by
minimum acceptable value.
4. Set Angle Control to 1 5. OK
Rhino
1. File > Save As Select File Type
> STL
3. Enter a name for the STL file.
4. Save
5. Select
Binary STL Files SolidDesigner
1. File > Save
2. Select File Type
> STL
3. Select Data
4. Click OK
ScanIP
1. File > Export > STL...
2. Select parts for export
and export settings
3. Export
4. Enter Filename
5. Save
SolidEdge
1. File >
Save As
2. Set Save As Type to STL
3. Options
4. Set Conversion
Tolerance to 0.001in or 0.0254mm
5. Set Surface Plane Angle to 45.00
6. Save
SolidWorks
1. File
> Save As
2. Set Save As Type to STL
3. Options > Resolution
> Fine > OK
4. Save
Think3
1. File >
Save As
2. Set Save As Type to STL
3. 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 |
