Introduction:
Navigating the world of 3D printing involves understanding the nuances of CAD file formats and resolutions, especially when using HP Multi Jet Fusion (MJF) technology. The choice of file extension and resolution plays a pivotal role in the quality, accuracy, and efficiency of the printed model. This article discusses the recommended CAD file formats and resolutions for MJF 3D printing.
Preferred File Extensions: STL and 3MF
- STL Format: Despite its limitations in conveying detailed model information like color or distance units, STL remains the most commonly used file extension in 3D printing.
- 3MF Format: Developed by the 3MF Consortium to meet the evolving needs of the 3D printing industry, the 3MF file format supports advanced features like color, texture, and material definition. It’s typically lighter in file size compared to an STL file for the same model and resolution.
Tessellation or Faceting Process
- Tessellating a 3D model involves converting its geometry into linked triangles to represent its surface accurately. This step is crucial; incorrect tessellation can lead to geometric inaccuracies or slow processing.
Exporting Models from CAD Software
- Each CAD software has its method for exporting a model to an STL or 3MF file. Key parameters during this process include deviation chord height and angle tolerance, which define the resolution and size of the file.
Deviation Chord Height and Angle Tolerance
- Deviation Chord Height: This is the maximum distance between the geometry of the 3D model and the surface of the STL or 3MF file. A recommended value is 0.05 mm for higher accuracy.
- Angle Tolerance: This defines the maximum angle between the normal vectors of adjacent triangles. A recommended value is 1 degree for preserving surface details.
Managing Exporting Errors
- Common exporting errors include surface inaccuracies, like unexpected holes or unjoined triangles, and poor resolution. These issues can arise from incorrect file exporting and can be mitigated by adjusting parameters in CAD software.
Optimizing Triangle Count
- A balance between triangle count and model accuracy is essential. Excessive triangles increase processing time without improving accuracy, while too few can result in poor resolution.
Repairing STL and 3MF Files
- Repairing common errors in exported files can be achieved using software like Materialise Magics, Autodesk® Netfabb® Engine, or HP SmartStream 3D Build Manager.
Printer Resolution Considerations
- HP MJF technology has a voxel resolution in the Z axis of 80 microns, making it important to align critical dimensions to an integral number of voxels for precise manufacturing.
Conclusion:
Choosing the right file format and optimizing resolution parameters are key steps in preparing a 3D model for MJF printing. By understanding the intricacies of STL and 3MF formats, tessellation, and resolution settings, designers can significantly enhance the quality and efficiency of their 3D printed models, ensuring that they meet the desired specifications and quality standards.
