Multi jet fusion (MJF) is an exciting powder bed fusion 3D printing process that produces high-quality parts with excellent mechanical properties, fine detail, and smooth surface finishes. As one of the newest metal and plastic 3D printing technologies on the market, multi jet fusion is gaining popularity for its speed, quality, and cost-effectiveness.
This in-depth guide will explore everything you need to know about multi jet fusion 3D printing, including how it works, its key benefits and limitations, suitable applications, and leading MJF 3D printer manufacturers.
What is Multi Jet Fusion 3D Printing?
Multi jet fusion is a powder bed 3D printing process developed by HP and introduced to the market in 2016.
It involves the selective fusing of powder material in a bed using an inkjet print head to selectively deposit fusing and detailing agents. The fusing agent melts or sinters the powder to form Solid parts, while the detailing agent improves surface finishes and accuracy.
After each layer is selectively printed, a roller spreads a fresh layer of powder over the build platform as it lowers. This process repeats until the full part is complete.
The MJF process results in excellent isotropic properties, fine detail resolution, and smooth surface finishes comparable to injection molded parts. Parts also have excellent dimensional accuracy and stability.
Multi jet fusion can print in a range of plastic and metal materials, making it highly versatile for different applications. Print speeds are very fast compared to other powder bed technologies like selective laser sintering.
Key Benefits of Multi Jet Fusion 3D Printing Technology
There are several key advantages that make multi jet fusion a leading powder bed 3D printing process:
- High print speeds – MJF printers can produce parts up to 10 times faster than selective laser sintering due to the fast inkjet print head. A full build chamber can be printed in just a few hours.
- Excellent mechanical properties – Parts printed with MJF have exceptional isotropic properties with uniform strength in all directions. Tensile strength and elongation are similar to injection molded plastics.
- High resolution and detail – Print resolution reaches 1200 DPI with supports as fine as 650 microns thanks to the precise inkjet print head. Small features and complex geometries can be produced.
- Smooth surface finishes – The liquid detailing agent provides smooth, uniform surfaces without visible layer lines. MJF parts can be sanded and polished to injection molding-like smoothness.
- No residual powders – Unfused powder is easily removed and fully recyclable after printing, unlike SLS which leaves excess powder bonded to parts.
- Dimensional accuracy – Printed parts have excellent accuracy within 0.3% owing to precise thermal control and uniform powder packing during printing.
- Wide material range – MJF can print versatile materials like nylons, TPU, ABS-like plastics, and various metals for different applications and mechanical needs.
- Cost effective – MJF printers have a lower overall operational cost compared to SLS, with competitive part costs and savings on unfinished powder.
Limitations of Multi Jet Fusion Technology
Despite its benefits, MJF does come with some limitations to consider:
- Limited material range – The number of available materials is growing but still much less than other processes like FDM and SLS. Specialized materials like carbon fiber are not yet available.
- Large size limitations – The maximum part size is restricted to 10 inches x 13 inches x 16 inches on current MJF systems. Larger industrial systems are in development.
- Requires support removal – While not bonded like SLS, MJF supports still need removal and finishing for visual surfaces. Support contacts can affect surface quality.
- Limited precision – While accurate, MJF cannot match the sub-millimeter precision of other powder bed processes like binder jetting and selective laser melting.
- High upfront costs – MJF printers currently cost over $100,000 for starter professional systems. The powder materials are also more expensive than standard thermoplastics.
- Moisture sensitivity – Nylon materials for MJF must be dried properly before printing to prevent defects caused by moisture absorption.
Ideal Applications for Multi Jet Fusion 3D Printing
Thanks to its well-balanced set of properties, MJF excels at a range of different prototyping and production applications across industries:
- Functional prototypes – Smooth surface finishes, isotropic strength, and fast turnaround make MJF ideal for accurate functional prototypes.
- End-use parts – MJF can produce durable plastic and metal parts for end-use when properties match intended application needs.
- Composite tooling – Low volumes of composite layup tools and molds can be 3D printed with good surface quality and thermal resistance.
- Jigs, fixtures and workholding – Lightweight custom fixturing that withstands repeated use can be 3D printed on demand with MJF systems.
- Automotive parts – Interior and under-hood automotive parts like ducts, housings and fluid control parts can benefit from MJF capabilities.
- Aerospace interior components – MJF is great for aircraft interior parts like ducts, housings, and lightweight brackets.
- Orthodontic appliances – Clear biocompatible plastic resins can produce custom dental aligners and retainers.
- Medical instruments – Surgical guides, validated sterilization plastic instruments, prosthetics components.
- Consumer electronics – Multi-material MJF can embed electronics and assemble housings in a single print.
Leading Multi Jet Fusion 3D Printer Manufacturers
The MJF 3D printing process was developed and commercialized first by HP. Today, a growing number of companies now offer MJF-based 3D printing systems and materials:
The inventors of MJF, HP offers a range of MJF platforms from desktop to industrial systems under their Jet Fusion brand. Notable models include the 300/500 series, 3200/4200, and the Metal Jet series.
3D Systems
A key player in powder bed fusion, 3D Systems offers MJF capabilities on their Figure 4 line of scalable production 3D printers. Their MJF printing process uses Selective Thermoplastic Electrophotographic Process (STEP) technology.
Xaar
Xaar partners with inkjet manufacturer Xjet to provide MJF printing capabilities on the Carmel 1400 and Carmel 700 printers focused on ceramics and metal materials.
Aurora Labs
This startup offers the AX1 system, an open material platform for multi-material printing using inkjet technology capable of MJF-like applications.
Nexa3D
The NexaX2 combines stereolithography and MJF technologies into a professional desktop printer capable of multi-material prints.
Triditive
Triditive offers the AMTower MJF printer focused on high-temperature peek materials for industrial production applications.
The Future of Multi Jet Fusion 3D Printing
As a newer 3D printing process, MJF is still evolving with expanded capabilities on the horizon:
- Larger build volumes – Industrial systems under development target 1 meter cubic build volumes for mass production needs.
- Expanded materials – New high-performance polymers, elastomers, composites, and alloys will broaden applications.
- Multi-color/Multi-material – Printers in development allow composite materials and mixes for full-color multi-material parts.
- Process improvements – Faster print speeds, reusable print agents, and lower costs will improve MJF capabilities.
- Hybrid manufacturing – Combined MJF and CNC machining or other secondary processes will enable complex printed end-use parts.
With its advantages in speed, quality, and capabilities, MJF has strong growth potential as both a prototyping and manufacturing solution as the technology progresses. The combination of high throughput and part quality make it an ideal process for 3D printed end-use parts across industrial and consumer applications.
