Multi-Jet Fusion (MJF) Design Guide
Review clearances, wall transitions, and powder escape paths when planning an MJF build.
Get the Guide With Your QuoteMJF 3D Printing Services
BoValley provides Multi Jet Fusion (MJF) 3D printing for functional plastic parts, design validation, and selected low-volume manufacturing projects. MJF is well suited to complex geometries and repeatable batches of nylon components when conventional tooling is not the preferred starting point.
Project Review
- CAD Review
- Powder Grade Selection
- Build Planning
- Fit and Finish Review
- Part Design
- Integrated features
- Build Planning
- Prototype & batch review
- Material Type
- Nylon powder grades
Overview
What is Multi-Jet Fusion (MJF)?
Multi Jet Fusion (MJF) is a polymer powder-bed fusion process. Fusing and detailing agents are selectively deposited across a powder layer, and heat is applied to fuse the material into a solid part. The process repeats layer by layer to form the component.
MJF is commonly associated with nylon-based functional parts. Its batch-oriented workflow can be useful when several components need to be produced together without investing in a dedicated injection mold.
Multi-Jet Fusion (MJF) Capabilities
MJF can be suitable for low-volume production of selected plastic parts, particularly when dedicated injection tooling is not justified.
Build Planning
- Keep wall transitions consistent where practical.
- Allow room for powder removal from enclosed regions.
- Test mating clearances and snap features in the selected grade.
- Agree on surface and color requirements before ordering.
Wall Thickness
- Keep wall transitions consistent where practical.
- Allow room for powder removal from enclosed regions.
- Test mating clearances and snap features in the selected grade.
- Agree on surface and color requirements before ordering.
Part Clearances
- Keep wall transitions consistent where practical.
- Allow room for powder removal from enclosed regions.
- Test mating clearances and snap features in the selected grade.
- Agree on surface and color requirements before ordering.
Powder Removal
- Keep wall transitions consistent where practical.
- Allow room for powder removal from enclosed regions.
- Test mating clearances and snap features in the selected grade.
- Agree on surface and color requirements before ordering.
Material Choice
- Keep wall transitions consistent where practical.
- Allow room for powder removal from enclosed regions.
- Test mating clearances and snap features in the selected grade.
- Agree on surface and color requirements before ordering.
Post-Processing
- Keep wall transitions consistent where practical.
- Allow room for powder removal from enclosed regions.
- Test mating clearances and snap features in the selected grade.
- Agree on surface and color requirements before ordering.
MaterialsMaterials
Multi-Jet Fusion (MJF) Materials
Start with a nylon grade compatible with the selected MJF platform. Review stiffness, flexibility, and surface requirements against the intended use.
- PA12 Nylon
- PA11 Nylon
- Glass-Bead-Filled PA12
- Specialty Engineering Grades
- PA12 grade selection
- Impact and flexibility
- Stiffness of filled grades
- Powder evacuation
- Build packing
- Wall consistency
- Thin feature strength
- Sliding fit
- Snap-fit flex
- Wear at mating surfaces
- Heat exposure
- Surface texture
- Dye compatibility
- Build orientation
- Finish consistency
- Hollow part access
- Cleaning requirements
- Dimensional stability
- Mechanical testing
- Material availability
Surface Finish Options
Both MJF and SLS can produce complex functional plastic parts. The best choice depends on material availability, part geometry, dimensional requirements, surface finish, quantity, and total project cost.
| Parameter | Typical Capability / Options |
|---|---|
| Process | Multi Jet Fusion (MJF) |
| Material Type | Polymer powder |
| Common Materials | PA12, PA11, and selected filled PA12 grades, subject to system availability |
| Build Size | Depends on the printing system and part layout |
| Dimensional Accuracy | Depends on material, geometry, build conditions, and measurement method |
| Surface Finish | Generally matte; color and texture depend on material and finishing |
| Post-Processing | Powder removal, blasting, dyeing or other agreed finishing |
| Typical Order Volume | Functional prototypes and selected low-volume batches |
The Process
How Does Multi-Jet Fusion (MJF) Work?
Design decisions should account for wall thickness, clearances, powder removal, part orientation, dimensional tolerances, and the intended mechanical function. Large flat surfaces and tightly fitted features may need special
The advantages
- Batch Production Potential:• Suitable for producing multiple components within a coordinated build.
- Fine Feature Reproduction:• Supports detailed geometry within the limits of the selected material and process.
- Complex Geometry:• Enables integrated shapes that may otherwise require multiple components or machining setups.
The challenges
- Functional Thermoplastics:• Useful for selected mechanical, fit, and assembly evaluations.
- Build Layout Efficiency:• Part nesting may help make efficient use of the build volume, depending on geometry and process rules.
QualityApplications for Multi-Jet Fusion (MJF)
MJF is a strong candidate for functional plastic parts and selected low-volume batches where design flexibility and repeatable production planning matter.
Functional Prototypes
Validate part geometry and mechanical concepts.
Enclosures & Brackets
Manufacture selected housings, mounts, and structural parts.
Complex Assemblies
Explore designs with integrated features and reduced part count.
Low-Volume Production
Produce selected end-use components without injection mold investment.
Consumer product development
Test housings, clips, and other plastic parts before tooling decisions.
Custom fixtures and assembly aids
Build handling and assembly aids with integrated locating features.
| Types of Parts | Function |
|---|---|
| Snap-fit housings | Check the fit and deflection of integrated fastening features. |
| Functional brackets | Evaluate load and assembly interfaces in nylon. |
| Assembly fixtures | Locate and hold parts during pilot assembly. |
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