Introduction
HP Jet Fusion 3D printing has emerged as one of the most advanced additive manufacturing technologies available today. Unlike traditional manufacturing or other 3D printing methods like Fused Deposition Modeling (FDM) or Selective Laser Sintering (SLS), MJF delivers high-speed, high-resolution printing with superior mechanical properties.
For engineers and manufacturers looking to optimize part performance, accuracy, and cost efficiency, designing specifically for MJF is crucial. Whether you’re creating functional prototypes, aerospace components, medical devices, or industrial-grade parts, following best practices ensures you maximize the benefits of this powerful technology.
This blog post explores key design considerations, material choices, structural best practices, and post-processing techniques to help you achieve the best results with HP Jet Fusion 3D printing.
Why HP Jet Fusion? The Key Advantages
1. Isotropic Mechanical Properties
Unlike FDM, which suffers from weak interlayer adhesion, MJF produces uniform strength in all directions. This means your parts will perform more like injection-molded components, with consistent durability and structural integrity.
2. High-Speed Production
MJF is significantly faster than both SLS and SLA printing. The ability to print large batches without the need for support structures makes it an ideal choice for production-scale manufacturing.
3. Exceptional Surface Quality and Detail Resolution
MJF produces smoother, more detailed parts than SLS, with a finer powder that allows for better feature resolution. This makes it a great option for engraved text, logos, and intricate mechanical components.
4. Cost-Effective and Low Material Waste
MJF is designed for efficient powder reuse, reducing overall material waste and making it a more sustainable, cost-effective option compared to other powder-based 3D printing methods.
Best Practices for Designing with MJF
1. Material Selection: Choosing the Right Polymer for Your Application
The mechanical properties of an MJF part depend heavily on material choice. The most common materials used in HP Jet Fusion printing include:
- Nylon PA12 – High strength, chemical resistance, great for mechanical parts.
- Nylon PA11 – More flexible than PA12, excellent for impact-resistant components and medical applications.
- TPU (Thermoplastic Polyurethane) – Rubber-like elasticity, great for seals, gaskets, and flexible structures.
Selecting the right material ensures the best performance in terms of strength, flexibility, and durability.
2. Structural Integrity: Wall Thickness and Geometric Considerations
Wall Thickness Guidelines
- Minimum wall thickness: 0.3 mm in the XY plane, 0.5 mm in the Z direction
- Large flat surfaces: Increase thickness to prevent warping
- Long, unsupported structures: Add ribs or fillets to reduce stress concentrations
Thin walls should be carefully designed to avoid weak sections and ensure proper fusing during printing.
Cantilevered Features
Cantilevered structures tend to warp or sag if not properly supported. Design recommendations:
- Width <1 mm: Maintain an aspect ratio ≤1 (length/width)
- For longer cantilevers: Add reinforcing ribs or fillets
Avoiding Warping in Long, Thin Parts
- Keep aspect ratio below 10:1
- Introduce internal lattice structures for better heat distribution
- Avoid sudden cross-section changes that create stress points
3. Designing for Assembly: Tolerances and Clearances
If your design involves interlocking or moving components, ensure proper tolerances and clearances:
- Mating parts: Maintain a minimum clearance of 0.4 mm to accommodate dimensional variations.
- Snap-fit features: Leave slight interference for a secure fit, based on material flexibility.
- Moving parts and hinges: Keep at least 0.7 mm of clearance to prevent fusing during printing.
Precision assembly requires careful iterative testing to fine-tune tolerances.
4. Lightweighting Strategies: Reducing Mass Without Sacrificing Strength
Reducing weight while maintaining mechanical performance is crucial in aerospace, automotive, and robotics applications. The best methods include:
Hollowing
Rather than printing solid blocks, remove excess material inside parts while maintaining a minimum wall thickness of 2 mm.
Lattice Structures
Lattices reduce material usage while maintaining strength through a network of load-bearing beams. Keep lattice gaps at least 5 mm wide to ensure powder removal after printing.
Topology Optimization
Using Finite Element Analysis (FEA), topology optimization identifies non-critical areas where material can be removed. This is especially useful in weight-sensitive applications.
5. Achieving High Dimensional Accuracy
HP Jet Fusion can achieve IT Grade 13 tolerances, but part accuracy depends on design considerations.
Design Tips for High Accuracy
- Align critical dimensions in the same plane to reduce variations.
- Embossed and engraved details should be at least 1 mm in depth or height for readability.
- Avoid long, thin sections prone to thermal deformation.
For mission-critical applications, test prints and minor design tweaks help refine accuracy before final production.
6. Aesthetic and Surface Quality Considerations
HP MJF prints at 80 µm layer resolution, which minimizes visible layer lines, but orientation affects finish quality.
Minimizing Layer Lines
- Avoid shallow angles (<20°), which may show visible stepping.
- Orient parts strategically to face the best surface finish outward.
- Post-process with bead blasting or vapor smoothing for an even better finish.
For consumer-facing products, surface refinement through dyeing or chemical smoothing enhances appearance and feel.
7. Post-Processing: Cleaning and Finishing MJF Parts
Once parts are printed, proper post-processing ensures functionality and aesthetics.
Powder Removal Best Practices
- Hollow parts must have drain holes (≥ 5 mm) for effective powder extraction.
- Use a flexible screw or bead blasting to clear powder from ducts and fine internal channels.
Surface Treatments
- Dyeing – Uniform color application without affecting mechanical properties.
- Vapor Smoothing – Improves surface finish, making parts smoother and more watertight.
- Coatings and Sealants – Enhance durability for wear-resistant or chemical-resistant applications.
Conclusion: Optimizing for Success with HP Jet Fusion
Designing for HP Jet Fusion 3D printing requires a deep understanding of material properties, structural integrity, and manufacturing constraints. Following these best practices ensures parts are strong, accurate, and cost-effective, whether for functional prototypes or full-scale production.
By leveraging lightweighting strategies, optimized tolerances, and post-processing techniques, engineers can push the boundaries of what’s possible with additive manufacturing.
For those looking to maximize their results with HP Jet Fusion, working with an experienced MJF partner can make all the difference.
Partner with RapidMade for Expert HP Jet Fusion 3D Printing
At RapidMade, we specialize in high-precision HP Multi Jet Fusion printing, offering:
✅ Design consultation to optimize for MJF
✅ Prototyping and production with fast turnaround
✅ Post-processing and finishing services
🔗 Visit RapidMade.com to request a quote or speak with an expert!
