Multi Jet Fusion and Traditional Molding Methods: When Is MJF More Cost-Effective?

Modern plastic manufacturing offers various technologies, each with its own advantages and limitations. A comparison of MJF and traditional molding shows that depending on production scale, product design requirements, and economic factors, the choice of method can significantly impact the final cost and production time. In this article, we’ll explain why MJF outperforms traditional plastic casting, and examine the advantages of MJF compared to traditional plastic molding methods.

Key Differences Between MJF and Injection Molding

Multi Jet Fusion (MJF) is an additive manufacturing technology developed by HP that uses thermal sintering of powdered material with a special binding and detailing agent. This process enables the fast production of strong and highly detailed parts without the need for support structures during printing. 

Injection molding, on the other hand, is a traditional production method where molten polymer is injected into a mold under high pressure. This method is efficient for mass production, as once the mold is created, the manufacturing process is both fast and cost-effective.

Before determining in which cases MJF surpasses traditional plastic injection molding, it’s important to examine the key differences between these technologies:

Operating principle. Injection molding requires the creation of a mold into which molten material is introduced under high pressure, whereas MJF uses an additive manufacturing method, fusing material particles layer by layer to create a product.

Production speed. MJF enables faster production of plastic parts as it eliminates the need for mold fabrication, particularly important for small-batch manufacturing.

Design flexibility. MJF excels in creating complex geometries that are difficult or impossible to achieve with injection molding.

Production costs. In small-batch production, the time and cost savings provided by MJF make this technology more advantageous compared to molding.

Waste minimization. Unlike traditional manufacturing, additive technologies allow for the use of the minimum amount of material necessary.

Supply chain simplification. Manufacturers can produce parts directly on-site, reducing logistics costs.

When MJF Becomes More Advantageous

What criteria can be used to compare MJF with injection molding in plastic manufacturing? The primary factor to consider is the scale of production:

Prototyping and testing new products. MJF outperforms traditional molding in creating test samples, eliminating the costs associated with mold production.

Small-batch production. The economic benefits of MJF are evident when producing small batches of parts (up to several hundred pieces): at such volumes, investments in molding equipment are not justified.

Products with complex geometries. Injection molding has material limitations, and in cases where a product requires non-standard shapes and high detailing, MJF delivers better results.

Production of unique parts. MJF enables the manufacturing of customized components without additional tooling costs.

Advantages and Disadvantages of MJF

Advantages of MJF over traditional plastic molding:

Design flexibility. The technology allows for the production of parts with cavities, complex channels, and varying wall thicknesses without additional costs.

Production speed. There is no need to manufacture molds, reducing the time required to produce parts.

Cost savings for small batches. The absence of significant initial investments makes MJF a more favorable option for small-scale production.

Adaptability to design changes. One of the most significant benefits of MJF in plastic part production is the ability to quickly make modifications without reworking molds.

Environmental sustainability. MJF helps companies reduce waste and enables the recycling of powder materials.

Reduced storage costs. On-demand manufacturing of parts minimizes storage expenses.

Challenges of MJF compared to injection molding:

Cost per unit in large volumes. In general, for serial production of hundreds or thousands of units, injection molding becomes the more cost-effective option.

Limited material selection. MJF uses a specific range of materials compatible with this technology, which may restrict material choices for customers.

Dimensional accuracy. Although MJF ensures high quality, parts may require post-processing to achieve the required dimensions.

Practical Cases: When MJF Is More Effective

Prototyping an Aluminum Profile. Infomir 3D Printing used MJF technology to create a prototype aluminum profile intended for testing before launching mass production. The client needed to verify the compatibility of the new profile with existing fasteners and mechanisms. The HP PA 12 polyamide used in MJF provided high strength and heat resistance, which were critical for mechanical structures. Thanks to this technology, several design iterations were printed in just three days, whereas traditional molding would have taken at least 4–6 weeks. As a result, the client saved up to 80% of preparation time and was able to start production faster.

Respirator Cover for Microfilter LLC. Medical device manufacturer Microfilter LLC faced the urgent need to produce respirator covers for new device models. The traditional injection molding method would have required mold development and fabrication, taking at least six weeks and costing approximately $10,000. With MJF, the covers were printed in just five days, allowing the company to begin serial production without significant delays. The HP PA 12 polyamide used in MJF is biocompatible and resistant to disinfecting solutions, making it an ideal material for medical products. Additionally, the technology enabled quick design modifications without extra mold-related costs.

Enclosures for Sumix. Sumix, a company specializing in optical equipment development, approached Infomir 3D Printing to manufacture enclosures for a new device. Traditional methods such as injection molding were not cost-effective due to the small production volume and long mold preparation time. Thanks to MJF and the use of high-strength HP PA 12 polyamide, which is resistant to UV light and chemicals, the enclosures were manufactured in just five days. This allowed Sumix to quickly test the product and move to production without significant time delays and financial costs.

When comparing MJF and plastic molding technologies, both have their pros and cons. MJF surpasses plastic molding methods in small-batch production, prototyping, and creating complex products due to its flexibility, speed, and cost efficiency. MJF also has the added benefits of allowing quick modification of designs, reduction in waste, and production process optimization.