Are you troubled by poor print quality while 3D printing STL file? Are unmanageably large 3D files getting created when STL file is exported in high resolution? Don’t worry. This post would guide you step by step on ways to overcome these problems.

About STL Files

STL or Standard Triangle Language file is considered industry standard for printing on 3D printers. A sequence of triangles is used for representing the solid model’s surfaces in STL. Contemporary CAD (Computer Aided Design) programs permit export of their respective proprietary file formats in STL type for ease of 3D printing. Conversion of the 3D models into G-Code machine language is done through ‘slicing’ to render them print ready.

For accurately exporting 3D print ready models into STL files for convenience of 3D printing, you need to follow the steps mentioned below. Adhering to them would also lead to reduction in the 3D printing related expenses.

  • Get a clear view of STL resolution

    As stated earlier, a sequence of linked triangles is used by the STL format for recreating solid model’s surface geometry. As the resolution is increased, the number of triangles used would also go up in number. This would lead to better approximation of the 3D models’ surfaces. However, the STL file’s size also increases.

    When the model is exported in very low resolution, the triangles would be visible on the surface of the model after printing. This is something you won’t want on your model’s body. But, you can utilize the digital look for creating ‘low-poly’ models. It is not desirable that you increase the resolution after a certain degree. You would not get any new benefit. Extremely minute details cannot be captured in 3D prints. However, such an increase would lead to unnecessary enlargement in the file’s size. Consequently, large files would pose problems in handling and processing.

  • Select appropriate parameters for exporting

    By changing the tolerance within CAD program, the resolution of STL files can be modified. If you are not sure about the tolerance level, go for ‘high’ preset. This is the best bet when you want to generate STL file that can be conveniently 3D printed.

    STL resolution is specified in different CAD software in differing manners. However, 2 parameters are common to all packages i.e. angle and chord height.

    Chord height represents the maximum distance between original CAD 3D model’s surface and the STL file’s surface which is allowed by CAD software. The surface curvature can be represented in highly accurate manner by keeping the chord height smaller. Chord height should be ideally kept at 1/20th of the thickness of 3D printing layer. The value should never go under 1 micron or 0.001 mm. The resultant STL file would be very accurate for applications that can help in optimum 3D printing. The print quality would not suffer if the model is exported in smaller tolerance value. This is because 3D printers commonly available are not capable of reproducing extremely high detailing level.

    The angular tolerance is used to keep the value of angle within adjacent triangles’ normals. It is set at 15 degrees by default. In some CAD program, you may come across this tolerance as value ranging from 0 to 1. You should persist with the default 15 degrees’ value or 0 in some programs as it is the recommended option. If you want the surfaces to be smoother, you can go for higher values.

  • Always use CAD software for exporting STL files

    The process of exporting STL files is unique to respective CAD software. You must follow the specific method of exporting for a given CAD program.

    You can export STL file from different software by following below mentioned methods.

    • Solidworks

      Navigate to ‘Save As’ in ‘File’ menu. In ‘Set Save As’ box, select STL as the file type. Next, choose ‘Ok’ from ‘Options -> Resolution -> Fine (or Custom)’ menu.

    • 3DS Max

      Navigate to the 3DS Max Application Menu, choose ‘Export’ and then ‘Stereolitho (*.STL)’

    • AutoCAD

      Navigate to ‘Output -> Send Panel -> Export’. When the Command prompt appears, key in ‘Export’. After the ‘Export Data’ dialog box appears, key in a proper filename. Choose Lithography (*.stl) from ‘Files of Type’. Click Save. You can choose one or more than one solid objects.

    • Inventor

      Navigate to ‘File’ menu, choose ‘Print’ and then ‘3D Print Preview’. From top left of window, choose ‘Save Copy As’ and then ‘Save’

    • OnShape

      You would have ‘Part Name' here. Right click on it at bottom right. Choose ‘Export’ and from ‘Format’, choose ‘STL’. After specifying model units, choose export settings.

    • PTC Creo

      Navigate to ‘Save As..’ under File menu and then select ‘Save a Copy’. The Type is to be changed to ‘Stereolithography (*.stl)’. Once you click ‘OK’, a new ‘Export STL’ dialog box will show up. From under ‘Deviation Control’, change the export settings.

    • Rhino

      Navigate to ‘Save As’ under ‘File’ menu. Choose ‘Stereolithography [*.stl]’ from ‘Save As…Box’.

    • SketchUp

      Start SketchUp after downloading the version to STL or DXF plugin. From ‘Tools’ menu, choose ‘Export to DXF or STL’.

    • Solid Edge

      From File menu, choose ‘Save As..’. From ‘Set Save As..’, choose file type as STL. From ‘Options’, select ‘Export’ as option.

    • ZBrush

      You have to bring down the polygon count adequately by using ‘Decimation Master’. Choose ‘Export as STL’ from ‘3D Print Hub’ under ‘Zplugin’.

For exporting, you need to keep chord height to 0.001 mm. The angular tolerance should be 15 degrees. This would give optimum outcome while 3D printing. You should not export STL files which are very large in size.

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