Introduction
In HP Multi Jet Fusion (MJF) 3D printing, creating large or complex parts often requires splitting them into multiple pieces and bonding them post-printing. This approach is essential in cases where parts exceed the build chamber size or when optimizing packing density. Understanding how to effectively design split and bonded parts is crucial for maintaining structural integrity and achieving desired aesthetics.
Splitting Big Parts for Efficient Printing:
Splitting parts becomes necessary when dealing with oversized designs or when seeking to optimize the packing density for cost and productivity efficiency. In industries like automotive or for applications such as jigs and fixtures, this method allows for the production of large components that maintain strength and functionality.
Design Considerations for Splitting Parts:
- Bonding Robustness: The design of the union between split parts is key to ensuring robust bonding. The choice of union design should be influenced by the final use of the parts, ranging from simple unions for visual prototypes to complex ones for load-bearing automotive components.
- Union Design Options: Depending on the thickness of the bonded parts and the possibility of modifying the geometry, various designs can be employed. For thicknesses less than 1.7 mm, dove or jigsaw features are recommended to increase the bonding area and ensure proper alignment.
Enhancing Bonding Performance:
- Multiple Union Features: When dealing with long bonding lines, incorporating multiple features that hold both pieces together during adhesive application can be beneficial. This ensures proper alignment and absorbs dimensional variations.
- Combination of Joint Designs: Using an overlap joint combined with reference features like jigsaw patterns optimizes bonding performance. These features can be added to non-visible surfaces for aesthetic considerations.
- Surface Textures and Grooves: Adding textures or grooves to the bonding surfaces can improve mechanical adhesion by increasing the effective bonding area.
Stress Considerations in Split Parts:
When designing split parts, consider the loads and stresses that will be applied to the final assembly. The design should minimize peel, cleavage, or tension stress, as adhesive bondings perform better under shear or compression stress. Introducing overlaps in the joints can help develop a bonding that is more effective under shear stress.
Conclusion
Designing for splitting and bonding in HP Multi Jet Fusion requires careful consideration of the union design, the stresses applied to the final assembly, and the bonding methods. By following these guidelines, engineers can create large and complex parts that maintain structural integrity and aesthetic quality. This approach not only extends the capabilities of MJF printing but also ensures that the final products meet the highest standards of performance and appearance.
