What is Multi Jet Fusion 3D Printing

Multi Jet Fusion (MJF) 3D printing isn’t just another method in the manufacturing toolkit, it’s a revolution. From automotive dashboards to customized medical devices, MJF brings ideas to life faster than ever before. It’s a powerhouse, merging speed with precision to change not only how products are made but also the speed at which industries innovate.

What sets MJF apart, and how does the multi jet fusion work? Imagine creating complex, durable parts with the freedom to experiment with design and function without the usual constraints. Now, with options like vibrant color finishes and flexible materials for lifestyle products, MJF is opening doors to new creative possibilities.

In this article, we’ll discuss how this technology is transforming traditional manufacturing and what it means for the future of production.

What is Multi Jet Fusion in 3D Printing?

Multi Jet Fusion is an advanced powder-based additive manufacturing technology that layers thin amounts of thermoplastic material, fused together by specialized agents and heat. This process results in parts with excellent isotropic mechanical properties, detailed resolution, and substantial tensile strength—qualities that can reach up to around 48 MPa (6,960 psi) under certain test conditions. Distinct from other powder bed fusion methods, MJF incorporates binder-jet-like steps, applying fusing and detailing agents before using infrared energy to sinter the material. This immediate application of heat creates parts that are denser and less porous than those produced by traditional cold binder jetting, setting MJF apart in the realm of 3D printing technologies.

Short History of Multi Jet Fusion 3D Printing

The journey of Multi Jet Fusion began in the mid-2010s when HP introduced its innovative approach to the existing powder-bed printing techniques, which were eager for enhancements in speed and scalability for more production-focused outputs. This development was not just an iteration; it was a leap forward, addressing the crucial need for efficiency in rapid prototyping and production. Early versions of HP Multi Jet Fusion printers quickly captured the market’s attention, offering faster production times and scalability previously unattainable in powder-based systems. Subsequent updates have pushed the boundaries further, enhancing the speed, enlarging the build volumes, and introducing new materials to cater to a wide range of specialized applications.

How Does Multi Jet Fusion 3D Printing work?

Multi Jet Fusion (MJF) 3D printing begins by distributing a thin layer of thermoplastic powder across the build platform. An inkjet array precisely deposits fusing and detailing agents onto the powder bed, defining the areas to be solidified. Following this, infrared energy is applied, fusing the agent-treated areas. This process is not only precise but rapid, repeating layer by layer to construct a solid part surrounded by unfused powder, which supports complex geometries without the need for additional support structures. Each cycle of the process repeats with incredible accuracy, supporting the creation of complex structures without the need for additional supports.

The high efficiency of MJF is demonstrated by its ability to fuse entire cross-sections simultaneously, which significantly speeds up the printing process compared to traditional point-by-point methods. Advanced MJF printers enhance this efficiency further by integrating separate stations for cooling and post-processing, thus enabling a continuous workflow and reducing downtime between builds. The layer thickness typically ranges from 80 to 100 microns, which contributes to the fine feature resolution and crisp edges of the final product.

What are the Key Stages of the Multi Jet Fusion 3D Printing Process?

The MJF process unfolds through several meticulously executed stages:

• Powder loading and build setup: The machine is prepared with the appropriate material and build parameters are configured.
• Spreading a thin powder layer: A uniform layer of powder is rolled over the build area to ensure even distribution.
• Deposition of fusing and detailing agents: Agents are jetted onto the powder where parts are to be fused, dictated by the part design.
• Infrared lamp fusing: The areas with agent are exposed to infrared light, causing the powder to melt and bond, forming a solid layer.
• Build platform lowering: The platform descends slightly to accommodate the next layer of powder.
• Repeating the process: These steps are repeated until the part is complete.

What are the Post-Processing Steps for MJF Parts?

Once MJF parts are printed, they undergo several post-processing steps to refine quality and functionality:

• Cooling within the build unit: This is crucial to prevent warping as the parts come down to room temperature.
• Depowdering: The excess powder or loose powder is removed using various methods, including brushing and compressed air, in a dedicated depowdering station.
• Bead blasting: A gentle abrasive technique that cleans and enhances the surface finish of the parts.

Note that powder from the build process can be reused at rates up to around 80%, contributing significantly to the cost-effectiveness of MJF. Depending on the application requirements, additional post-processing such as machining, painting, dyeing, or sealing may be necessary. Some parts are even capable of being post-processed in full color if they were printed with powders optimized for color application.

What are the Materials Used in MJF 3D Printing?

Multi Jet Fusion (MJF) 3D printing utilizes a variety of materials tailored for specific applications, each offering unique properties to meet diverse manufacturing needs:

• Nylon (PA12): Known for its strong balance of strength, chemical resistance, and fine detail resolution. PA12 is typically printed in a neutral gray finish, which can be easily dyed or coated for customized appearances.
• Nylon (PA11): Offers greater ductility and impact resistance, making it ideal for parts requiring flexibility or high shock absorption, such as protective gear and flexible joints.
• Polypropylene (PP): This material is lightweight yet durable, with excellent chemical resistance, making it suitable for automotive applications, fluid tanks, and containers.
• Glass-Filled Nylon: Incorporates glass additives to enhance rigidity and thermal stability, perfect for functional prototypes exposed to high temperatures or mechanical stress.

Additional materials used in MJF include:

• Flexible Elastomers (e.g., TPU and TPA): These materials are increasingly popular in applications requiring elasticity, such as footwear and sports equipment, due to their adaptability and comfort.
• White PA12: Offers enhanced aesthetic options through vibrant dyeing possibilities, allowing for more visually appealing and colorful product finishes.

What Are Multi Jet Fusion 3D Printing Advantages?

Multi Jet Fusion technology stands out for its numerous advantages over traditional manufacturing and other 3D printing methods:

• Speed: MJF prints parts faster than many laser-based 3D printing systems, making it suitable for rapid prototyping and production.
• Consistent Quality: It offers consistent isotropic mechanical properties across the printed parts, ensuring consistent performance and structural integrity.
• Waste Reduction: The ability to reuse powder and the absence of necessary support structures significantly reduce material waste.
• Dimensional Accuracy: MJF maintains excellent dimensional accuracy, with typical tolerances of ±0.3 mm or around ±0.15% of nominal dimensions, ideal for precision components.
• Cost-Effectiveness: The balance of cost and quality makes MJF advantageous for small to mid-sized production runs, providing high-quality parts at a reduced cost.

What Industries Rely on Multi Jet Fusion 3D Printing?

MJF technology is instrumental across various sectors, leveraging its rapid production capabilities and high-quality outputs:

• Automotive: Manufacturers use MJF for producing durable, lightweight components such as housings, brackets, and ducts.
• Medical Devices: This industry benefits from MJF for prototyping and manufacturing end-use medical components that require precise mechanical properties and sterility.
• Consumer Products: Companies rapidly iterate functional prototypes for gadgets, home appliances, and wearables.
• Robotics & Drones: MJF is ideal for fabricating complex, lightweight parts that contribute to the advanced functionality and mobility of robots and drones.
• Industrial Manufacturing: The technology is also pivotal in creating customized jigs, fixtures, tooling, and low-volume end-use parts.

What Are The Main Parameters of Multi Jet Fusion in 3D Printing?

Multi Jet Fusion (MJF) 3D printing technology is characterized by several crucial parameters that significantly influence the final quality and functionality of the printed parts. These parameters include layer thickness, build volume, and material properties, each playing an important role in the process’s efficiency and output.

Layer Thickness

In MJF, the typical layer thickness is around 80 microns, which facilitates fine detail resolution and smooth surface finishes. This precise control allows for variations in detail and speed, as some MJF printers can adjust the layer thickness within an 80–100 micron range. Thinner layers generally enhance surface smoothness and dimensional accuracy but may slightly increase the overall print time, affecting the production efficiency.

Build Volume

The build volume in MJF printers can vary significantly, with different models catering to various production scales. Industrial-grade machines, for example, often support larger build volumes—approximately 380 x 284 x 380 mm—allowing for higher throughput by accommodating multiple parts in a single print job. This capability is particularly beneficial in reducing lead times for batch production, making MJF an ideal solution for both prototyping and manufacturing needs.

Material Properties

MJF is renowned for its ability to produce parts with isotropic mechanical properties, meaning the strength is uniform in all directions. Tensile values for MJF materials can reach up to around 48 MPa, comparable to those of injection-molded parts. Additionally, MJF materials typically exhibit lower moisture absorption than those used in other 3D printing methods, enhancing the durability and longevity of the parts. The technology also supports a range of flexible materials, offering properties suitable for shock-absorption applications, further diversifying its use across various industries.

Dimensional Accuracy

Dimensional accuracy in MJF printing typically falls within a ±0.3 mm range, although this can vary based on the design geometry and size of the parts being produced. In some cases, particularly for larger parts, the accuracy can be as precise as ±0.15%, staying well within the 0.3 mm tolerance limit. Consistent heating across the build area is crucial as it enhances the repeatability of the printing process, especially beneficial during series production runs, ensuring that each part meets strict specifications.

How accurate is MJF printing?

The precision of MJF printing is highlighted by its ability to produce parts with crisp edges and detailed features. This is facilitated by the controlled deposition of fusing and detailing agents, combined with rapid fusing technology. Proper part orientation within the build platform is critical for optimizing the accuracy of these dimensions, ensuring that the most critical dimensions align parallel to the build plane. Additionally, post-processing techniques such as bead blasting are employed to refine surface finishes without significantly impacting the tight tolerances achieved during the printing process.

Surface Roughness

MJF typically results in parts with relatively smooth surfaces compared to other 3D printing methods. However, the as-printed surfaces might still exhibit a slightly textured appearance due to the nature of the powder used. This texture can be further smoothed through post-processing methods like media blasting or polishing, which enhance the surface finish. For parts requiring near-cosmetic finishes, some materials used in MJF are specifically formulated to allow post-processing treatments that achieve smoother and more aesthetically pleasing surfaces.

Fusing and Detailing Agents

The roles of fusing and detailing agents are pivotal in MJF printing. The fusing agent is crucial as it absorbs heat, which melts the powder, forming a solid layer. Concurrently, the detailing agent works to refine the part’s edges, enhancing the resolution of surface details. These agents are jetted onto the entire powder bed in precise patterns, which not only ensures the accuracy of the print but also speeds up the process compared to laser-based systems. The sophistication of these agents and their application techniques contribute significantly to reducing overall print time while improving the sharpness of the printed features and minimizing bleed in fine details.

Cooling Time

In MJF 3D printing, the cooling time is vital for ensuring the dimensional stability and minimizing warping of the printed parts. Properly controlled cooling helps maintain the integrity of the part’s dimensions and structural properties. Some MJF systems incorporate dedicated external cooling modules that allow the printer to begin new builds more quickly while adequately managing the temperature of completed parts. For larger or thicker parts, extended cooling times are beneficial as they reduce thermal stress, helping to preserve the precision and quality of the final product.

Part Orientation

The orientation of parts during the printing process significantly affects the outcome in terms of structural integrity and surface quality. Correct part orientation helps minimize the visibility of layer lines and optimizes the strength of the printed parts. Strategically angling certain surfaces can enhance the smoothness of the finish, although it might slightly alter the accuracy of specific dimensions. Distributing the mass of the part evenly across the build platform also aids in maintaining consistent heat distribution throughout the process, which reduces the likelihood of local shrinkage and other distortions.

Minimum Feature Size

Multi Jet Fusion technology is capable of producing extremely fine details with a minimum feature size down to around 0.5 mm. However, it’s important to note that post-processing techniques may impact the precision of these tiny details. For optimal reliability and to prevent warping, designs with thicker walls, typically 1 mm or more, are recommended. Additionally, incorporating slight offsets and clearances in the design helps prevent unintended fusing of separate features, maintaining the integrity and distinctiveness of each part.

What is the Minimum Feature Size?

The precision of MJF allows for features as small as 0.3–0.5 mm to be accurately built, although a more conservative approach is advised for critical features to ensure their robustness and functionality. Employing strategies such as hollowing or shelling thicker features can effectively reduce printing costs and minimize potential defects like sink marks. Extra care should be taken when positioning delicate features near critical load-bearing areas to maintain structural integrity.

What is the Maximum Build Size of MJF Printers?

The maximum build size for MJF printers varies across different models, with many capable of accommodating mid-range volumes that are ideal for short-run production. Some of the more industrial-scale MJF systems can handle build dimensions up to approximately 380 x 284 x 380 mm. Utilizing the full capacity of the build volume by nesting multiple components within a single print job can significantly enhance the cost-efficiency of the production process, making MJF a versatile choice for a variety of manufacturing applications.

Print Speed

MJF is renowned for its remarkable speed, capable of producing parts up to 10 times faster than some traditional laser-based systems. This rapid production capability makes MJF highly attractive for rapid prototyping and small-scale manufacturing applications. Variability in print speed can occur based on the print mode selected, the type of material used, and the geometry of the parts being produced. Some MJF machines can achieve throughput exceeding 4,000 cm³ per hour in optimized settings, significantly reducing the cost per part when multiple items are produced simultaneously.

Powder Reusability Rate

One of the sustainable features of MJF technology is the high rate of powder reusability. Approximately 80% of the leftover powder can be recycled, substantially reducing waste and the overall cost of materials. MJF systems are equipped with efficient powder collection stations that facilitate the recovery and reuse of unfused powder. These systems typically allow for recycling rates that exceed 50%, which not only lowers material costs but also diminishes the environmental impact relative to single-use processes.

What is the Lead Time for MJF Parts?

The lead time for producing parts with MJF technology is impressively short, often just a few days, depending on the size of the printing batch, the required post-processing, and the availability of the machines. Large production runs can be expedited, especially when the build volume is fully utilized. Furthermore, the integration of rapid cooling modules and the ability to operate continuously near “24/7” significantly reduce backlogs in high-demand production environments, enhancing throughput and delivery times.

Are MJF 3D-Printed Parts Water-Resistant?

Multi Jet Fusion (MJF) 3D-printed parts exhibit excellent water resistance when designed and processed correctly. The primary material often used in MJF, nylon, is inherently capable of achieving watertight qualities if the print parameters are precisely controlled. Enhancing water resistance further, post-processing treatments such as chemical smoothing or the application of sealants can be applied. These steps ensure the parts meet higher standards of water resistance.

Some tests have shown that MJF parts can reach IP66 or IP67 ratings, indicating strong protection against water ingress, provided they are properly oriented and sealed during post-processing. The inherently low porosity of materials used in MJF also naturally inhibits water penetration, and finishing steps can be optimized to further bolster the water resistance of the final products.

Is Multi Jet Fusion 3D Printing Technology Expensive?

The cost of Multi Jet Fusion 3D printing can vary significantly based on several factors, including the size of the machine, the types of materials used, the volume of the batch, and the required post-processing. Although the initial investment in MJF technology can be high, especially for industrial-grade machines, the cost per part can decrease substantially with larger production volumes and frequent use.

MJF technology is known for its ability to reduce costs by up to 90%+ in certain scenarios, particularly for complex or medium-volume parts that would be more costly to machine traditionally. The ability to reuse powder and minimal support requirements also contribute to cost reductions. Furthermore, the cycle times are fast, which further drives down costs when compared to more traditional, laser-based 3D printing methods. Additionally, some providers offer MJF printing on-demand, which can help mitigate upfront costs and allow businesses to scale operations without significant initial investment.

How Much Does a MJF Printer Cost?

The cost of MJF printers varies, ranging from mid-five to six figures for industrial models, though more compact, newer models may be priced lower. When considering the acquisition of an MJF printer, it’s crucial to factor in not only the purchase price but also the ongoing operating costs, which include materials like powder and proprietary agents, as well as additional equipment such as processing stations.

Maintenance fees and service contracts are also significant considerations, as they can affect the total cost of ownership. Some MJF systems feature integrated unpacking and recycling modules, which, while potentially increasing initial costs, can accelerate the return on investment by enhancing production efficiency and reducing material waste.

How Long Does Multi Jet Fusion 3D Printing Typically Take?

Typically, the time it takes to complete a Multi Jet Fusion (MJF) 3D printing project can vary, but a standard build often requires between 1 to 2 days, depending on several factors. These factors include the machine’s capacity, the complexity of the part, the size of the batch, and the specific settings used for the print. Additionally, the amount of post-processing required and the efficiency of the cooling phases can also affect the total turnaround time.

In cases where large batch builds are involved, the use of continuous-run setups can significantly reduce downtime between jobs, enhancing overall efficiency. Moreover, comprehensive cooling cycles and thorough depowdering are critical for larger or more densely packed parts, as they add hours to the production timeline but are essential for achieving the desired quality and dimensional accuracy.

What Are Design Tips for Multi Jet Fusion 3D Printing?

When designing for Multi Jet Fusion 3D printing, there are several key considerations to ensure optimal print quality and structural integrity:

• Uniform Wall Thickness: Aim to maintain a wall thickness between 2.5 mm and 12.7 mm where possible to ensure consistent heat distribution and fusing.
• Reinforcing Ribs: Incorporate ribs for thin, flat surfaces to prevent warping and for raised bosses around holes to enhance structural integrity.
• Avoiding Detail Erosion: Small raised text and delicate features may degrade during the finishing processes like bead blasting or tumbling. Design these features with consideration to their susceptibility to wear.
• Cosmetic Considerations: Clearly mark cosmetic surfaces to minimize the visibility of layer lines, which can detract from the aesthetic appeal of the part.

Additional design strategies include hollowing or shelling parts thicker than 3-4 mm to reduce material usage and prevent warping.

What is the Environmental Impact of Multi Jet Fusion 3D Printing?

The environmental impact of Multi Jet Fusion 3D printing is relatively low compared to traditional manufacturing methods. One of the most significant environmental benefits is the high rate of powder reusability, with recycling rates for unused powder ranging from 50% to 80%. This capability not only reduces the amount of waste generated but also decreases the need for new raw materials.

Furthermore, the on-demand nature of MJF printing reduces the need for large inventories and long supply chains, which in turn lowers the carbon footprint associated with transportation and storage. The process also requires less tooling and produces lighter parts, which contributes to lower overall energy consumption during both production and the end-use phase.

What Are Some Common Problems and Defects with Multi Jet Fusion in 3D Printing?

Common defects and problems in Multi Jet Fusion 3D printing include:

• Warping and Curling: These issues often result from improper cooling or uneven heat distribution during the printing process.
• Incomplete Fusion: Occurs if the fusing agent is not applied adequately or if the temperature settings are too low.
• Surface Inconsistencies: Caused by residual powder or uneven application of detailing agents, leading to rough areas on the finished part.
• Feature Distortion: Thin walls or small features may distort if the print parameters are not optimized for such details.

What Maintenance is Required for MJF Printers?

Maintaining Multi Jet Fusion (MJF) printers is crucial to ensuring consistent, high-quality output. Here’s a rundown of essential maintenance steps:

• Printhead Maintenance: Regularly check and clean printheads to prevent blockages that can affect print quality.
• Powder Loading Systems: Calibrate these systems frequently to guarantee accurate and even layering of the powder.
• Chamber Maintenance: Regularly clean the build chamber and replace any worn components to maintain optimal thermal control.
• Filter and Lamp Checks: Keep an eye on filters and fusing lamps, replacing them as necessary to ensure they function correctly.

Some extra maintenance tips you might want to incorporate include:

• Preventive Maintenance: Schedule regular checks to prevent disruptions, particularly crucial in high-volume production environments.
• Powder Storage: Store printing powder in conditions with controlled humidity and temperature to extend its usable life and reduce defects.

What Are Alternative Technologies to Multi Jet Fusion 3D Printing?

Multi Jet Fusion is just one of many advanced manufacturing technologies. Alternatives include:

• Selective Absorption Fusion (SAF) and High Speed Sintering (HSS): These technologies use inkjet-deposited fluids and heat to sinter powder, similar to MJF, but vary in their specifics and available materials.
• Selective Laser Sintering (SLS): Unlike MJF, SLS uses a laser to sinter the powder, eliminating the need for binding agents.
• Binder Jetting: This method is prevalent in prototyping for its ability to print in plastics, though parts often require secondary processes to enhance strength and durability.

MJF vs Injection Molding

When comparing MJF to injection molding, several factors come into play:

• Tooling Investment: Injection molding requires high initial tooling investments, making it less cost-effective for small runs compared to MJF.
• Lead Times: MJF can produce parts within days, whereas injection molding may take longer due to the need for mold creation.
• Design Flexibility: MJF offers superior design flexibility, allowing for rapid iteration and the integration of multiple parts into a single build.

MJF vs SLS 3D Printing

Both MJF and Selective Laser Sintering (SLS) are powder-bed 3D printing processes, but they differ significantly in their approach:

• Printing Technology: MJF uses a combination of inkjet-deposited fusing agents and detailing agents, whereas SLS uses a laser to sinter the powder directly.
• Speed and Efficiency: MJF typically provides faster build speeds due to the simultaneous application of heat across a wide area, reducing the time required per layer compared to the point-by-point sintering of SLS.
• Material Options and Properties: While SLS has a broader range of materials due to its longer history, MJF often achieves better mechanical isotropy and can have higher powder reuse rates, contributing to lower overall material costs.

What is the Future of Multi Jet Fusion 3D Printing?

The future of Multi Jet Fusion (MJF) 3D printing is promising, with significant advancements on the horizon. Innovations include the development of newer machines offering larger build volumes, enhanced color capabilities, and expanded material compatibility. These improvements aim to further streamline production processes, reduce lead times, and expand the versatility of applications.

• Research in Materials: Efforts are ongoing to integrate specialized materials such as elastomers, flame-retardant polymers, and sustainable bio-based powders, broadening the scope of MJF applications across various industries.
• Technological Enhancements: Advancements in software for optimized part packing and real-time monitoring are expected to improve print yields and reduce cycle times, making MJF even more efficient and cost-effective.

How to Choose the Right MJF 3D Printer Supplier?

Selecting the right MJF 3D printer supplier is crucial for ensuring that your manufacturing needs are met with the highest standards of efficiency and quality. Here are key factors to consider:

• Industry Experience: Assess the supplier’s track record and expertise specific to your industry to ensure they can meet your requirements.
• Scalability and Capacity: Evaluate the MJF printing services to be sure thet can handle your project sizes and scale operations as needed.
• Material and Machine Options: Check the diversity of materials supported and the types of machines available.
• Comprehensive Services: Ensure the supplier offers comprehensive services including post-processing, quality assurance, and design-for-manufacturing support.
• Cost-Effectiveness: Inquire about powder refresh rates and finishing services like dyeing or painting, as these can significantly impact the overall cost-effectiveness and aesthetic outcomes of your projects.

Conclusion

We’ve seen that Multi Jet Fusion (MJF) 3D printing has changed the way we create and innovate in manufacturing. With its unmatched speed and versatility, MJF empowers us to transition from design to production faster than ever before, making it perfect for both rapid prototyping and crafting durable end-use parts.

This technology is not just about speed; it’s about transforming production floors by dramatically cutting tooling costs and reducing waste, bringing efficiency and sustainability to the forefront of industrial practices. The continuous advancements in MJF, from enhanced machine speeds to broader material choices and improved color capabilities, are setting new standards for what we can achieve.

Whether you’re in aerospace, automotive, healthcare, or consumer goods, embracing MJF technology means staying at the cutting edge of efficiency and creativity. Its ongoing evolution promises to further enhance our capabilities, enabling us to meet complex challenges with smarter, more adaptable solutions.

Frequently Asked Questions

Can MJF Produce Complex Geometries?

Yes, Multi Jet Fusion (MJF) is highly capable of handling intricate shapes and complex geometries without the need for separate support structures. The unfused powder naturally supports overhangs and intricate designs, allowing for the production of hollow or lattice-filled parts. This technology also enables the creation of components with internal channels or multiple moving joints in a single build.

Is SLS or MJF Better?

The choice between Selective Laser Sintering (SLS) and Multi Jet Fusion (MJF) depends on your project’s specific needs. MJF typically offers faster speeds and stronger isotropic properties, making it well-suited for producing robust, functional prototypes and end-use parts quickly. In contrast, SLS may offer a broader range of materials and is preferable for projects that require a wider variety of plastics.