Introduction
HP Multi Jet Fusion (MJF) technology stands at the forefront of 3D printing innovation, offering exceptional precision and versatility. However, maximizing the accuracy of MJF prints requires a thorough understanding of various factors. This guide outlines key practices and recommendations to optimize dimensional accuracy in MJF printing.
Optimizing Dimensional Accuracy:
Dimensional accuracy in MJF printing is influenced by the system’s operation at the voxel level, where adequate energy is crucial for properly fusing the intended sections layer by layer.
Printing Profiles and Materials:
- Balanced Print Profiles: Recommended for optimizing dimensional accuracy, especially for materials like HP 3D HR PA 11 (HP PA 11) and HP 3D HR PA 12 (HP PA 12).
- Material Considerations: HP PA 11 is better used with a Balanced print profile due to its dimensional similarity to HP PA 12 in the XY-plane but has a higher trade-off in the Z-axis.
Build Platform Placement and Printing Process:
- Critical Feature Orientation: Place small features like pins, holes, and raised texts upside-down on the XY plane for improved strength and appearance.
- Embossed Text: For increased clarity, print embossed text facing upwards.
- Part Spacing: Maintain a minimum distance of 5 mm between parts and 10 mm to 20 mm from the build volume margins for optimal results.
Warpage Concerns:
- Orientation for Large, Thin Parts: Place such parts parallel to the XY-plane and along the Y-axis to reduce thermal gradients.
- Central and Low Placement: For parts prone to warpage, position them centrally and as low on the platform as possible.
- Job Length: Shorter jobs minimize the Z-height and layers, allowing for faster printing and cooling stages.
Dense Parts Management:
- Part Orientation: For parts with uneven mass distribution, print them at an angle and not along clear array patterns to facilitate heat distribution.
- Separation and Packing Density: Ensure parts are well-separated (more than 10-15 mm) and maintain a packing density between 8% and 12%.
Dimensional Accuracy Examples:
- Honeycomb Plate Printing: Position the part so that critical features like positioning holes are on the XY plane. Use Slow Cooling for flat parts to preserve flatness.
- Phone Case Scenario: For cases that don’t require high accuracy but are prone to warpage, orient them perpendicularly to the XY-plane and parallel to the Y-axis.
Conclusion
Accurate MJF printing is a balancing act involving careful consideration of printing profiles, material selection, part orientation, and managing warpage. Adhering to these best practices can significantly enhance the dimensional accuracy of printed parts, making HP MJF an invaluable tool in various industrial applications.
