Foreword: The rapidly growing and highly competitive injection molding industry is worth hundreds of billions of dollars, prompting manufacturers to seek more efficient and lower-cost methods to stay ahead of the curve. Also known as additive manufacturing, 3D printing helps manufacturers create better injection molds and tooling faster and cheaper than traditional processes. This article mainly explains why you should choose 3D printing for molds.

Advantages and Disadvantages of 3D Printing Metal Molds

How to 3D Print Metal Molds?

3D printing expands the range of materials available, utilizes laser sintering to build layers, and transforms the CAD drawing into the ultimate three-dimensional product.

What are the Advantages of 3D Defined Metal Molds?

Improvements in Mold Design Add More Functionality to End Products

The special metallurgical method employed in metal 3D printing can enhance the metal microstructure and create fully dense printed parts. This method enables the integration of complex product functions, thus facilitating the production of highly functional end products in a more efficient manner with fewer defects.

For instance, the quality of an injection-molded part is greatly influenced by the heat transfer conditions between the injected material and the cooling fluid circulating through the tooling fixture. Traditional manufacturing processes usually feature straight channels for the cooling material, leading to a slower and uneven cooling effect on the molded part.

By contrast, 3D printing allows for the creation of cooling channels in any desired shape, ensuring conformal cooling that is more optimized and uniform. This, in turn, results in parts of higher quality and lower scrap rates. Moreover, the expedited heat dissipation considerably reduces the injection molding cycle time, as cooling typically constitutes up to 70% of the entire cycle duration.

Optimize Tools to be More Ergonomic and Improve Minimum Performance

3D printing significantly reduces the barrier for validating new tools to address unmet needs in manufacturing, enabling the creation of a greater number of moving and fixed fixtures. Historically, tools and related devices were engineered to maximize longevity, given the substantial expenses and efforts involved in redesigning and manufacturing them.

Through the utilization of 3D printing technology, companies gain the flexibility to refurbish any tool at any point, not solely those that have been discarded for failing to meet requirements.

Requiring minimal time and initial investment, 3D printing renders it more cost-effective to enhance tools for superior marginal performance. Consequently, technicians are able to prioritize aspects such as ergonomics in their designs to enhance operational comfort, decrease processing duration, and improve user-friendliness and storage convenience. While these enhancements may only result in a marginal reduction in assembly operation time, the cumulative impact should not be underestimated.

In addition, optimizing tool design can also reduce the scrap rate of parts. Same quality as machined molds; can make conformal cooling channels; uses less raw materials and faster than machined molds; can print multiple mold versions at one time; has higher application options, suitable for outsourcing manufacturers; prevents Data leakage, internal solution to protect intellectual property; injection molded parts have the same quality.

Shorter production cycles, the ability to manufacture more complex geometries, and lower final manufacturing costs allow companies to create a large number of personalized tools to support the manufacturing of customized parts.

Custom molds help customize the final product, and 3D printing molds are very beneficial for customized production, such as medical equipment and the medical industry. It can provide surgeons with 3D printed personalized instruments, such as surgical guides and tools, allowing them to improve surgical outcomes and reduce surgical time.

What are the Disadvantages of 3D Printing Metal Molds?

May take longer and cost more than machining; require more upfront design time; and demand higher skills. Post-machining processing may still be necessary to meet accuracy requirements, and mold sizes are limited. The most commonly used materials include stainless steel and tool steel.

What are the Typical Examples of 3D Printing Metal Molds?

Bridgestone

Creating high-quality all-season tires. Traditionally, tire molds were crafted by manually attaching strips and metal blocks in a specific pattern to a basic mold. The metal components, with their simple geometries, were crafted using conventional machining tools.

However, Bridgestone has embraced cutting-edge technology by utilizing SLM machines from German manufacturer SLM Solutions to produce 3D-printed metal molds. This innovative approach enables engineers to craft molds with shapes and patterns that were previously unattainable.

By redesigning the molds, tire traction performance can be enhanced without compromising the tire’s longevity. SLM Solutions has achieved a remarkable feat by successfully 3D printing a steel tire mold with a mere 0.3mm thickness at its thinnest point. Bridgestone isn’t the only industry giant leveraging 3D printing technology; Michelin has been offering tires manufactured using this advanced technique since 2013.

Eplus3D Cupping

In the past, manufacturers used traditional injection molding to produce cupping cups with low transparency and low injection molding efficiency. The main reason is that the cupping mold produced by traditional CNC technology can only process vertical cooling channels, which cannot effectively cool the mold. The cupping injection mold produced by EP-M250 SLM 3D printer features a complex conformal cooling channel metal mold produced using Eplus3D EP-M250 SLM 3D printer.

The final cupping only takes 16.63 seconds to reach the spray temperature. This is a significant improvement compared to traditional molds that take 22.97 seconds, resulting in a reduction of more than 6 seconds and increasing the injection efficiency by about 26%.

What are the Metal Mold Technologies and Materials?

Metal Mold Technology Mainly Includes

Selective Laser Melting (SLM)

approach in the additive manufacturing of metal materials. Despite the ability to achieve intricate details through this process, additional machining remains prevalent. Currently, due to cost considerations and processing speeds, metal 3D printing is unlikely to completely supplant the machining of injection molding tools. Instead, it serves as a complement that enhances the efficiency of overall production.

Direct Energy Deposition (DED)

The laser creates a molten pool in the deposition area and moves it at high speed. The material is directly sent into the high-temperature melting area in the form of powder or filament and is deposited layer by layer after melting. This method makes metal molds possible for a variety of metal materials. For instance, a top layer of stainless steel can be applied over a pure copper substrate to combine high thermal conductivity with wear resistance, properties required in injection molding tools.

Metal Mold Materials Mainly Include

According to the type of material, 3D printing metal materials can be divided into iron-based alloys, titanium and titanium-based alloys, nickel-based alloys, cobalt-chromium alloys, aluminum alloys, copper alloys and precious metals.

Iron-based alloy

Iron-based alloys are a type of alloy that has been studied earlier and more deeply in 3D printing metal materials. The more commonly used iron-based alloys include tool steel, 316L stainless steel, M2 high-speed steel, H13 mold steel and 15-5PH maraging steel, etc. . Iron-based alloys have low cost, high hardness, good toughness, and good machinability, making them particularly suitable for mold manufacturing.

3D printing conformal water channel molds is a major application of iron-based alloys. Special-shaped water channels are difficult to process with traditional processes. However, 3D printing can control the layout of the cooling channels to be basically consistent with the geometry of the cavity, which can improve the uniformity of the temperature field and effectively Reduce product defects and increase mold life.

Titanium and titanium alloys

Titanium and titanium alloys have become ideal materials in the fields of medical devices, chemical equipment, aerospace and sports equipment due to their remarkable high specific strength, good heat resistance, corrosion resistance, and good biocompatibility. However, titanium alloys are typically difficult-to-machine materials.

They suffer from high stress, high temperature, and severe tool wear during processing, which limits the wide application of titanium alloys. 3D printing technology is particularly suitable for the manufacturing of titanium and titanium alloys. First, 3D printing is in a protective atmosphere environment. Titanium does not easily react with elements such as oxygen and nitrogen. The rapid heating and cooling of micro-areas also limits the volatilization of alloy elements;

Second, complex shapes can be manufactured without cutting processing, and the material utilization rate based on powder or wire materials is high, which will not cause waste of raw materials and greatly reduce manufacturing costs. Currently, the types of 3D printed titanium and titanium alloys include pure Ti, Ti6A14V (TC4) and Ti6A17Nb, which can be widely used in aerospace parts (Figure 3) and artificial implants (such as bones, teeth, etc.).

Advantages and Disadvantages of 3D Printing Plastic Molds

How to 3D Print Plastic Molds?

Utilizing durable and heat-resistant materials in conjunction with a plastic (or polymer) 3D printer enables companies to produce their injection molds internally or swiftly procure them from a service provider.

What are the Advantages of 3D Printing Plastic Molds?

Optimize Tools to be More Ergonomic and Improve Minimum Performance

3D printing reduces the barriers to validating new tools that cater to unmet manufacturing needs, enabling the integration of more movable and fixed fixtures into production processes. Conventionally, tools and related equipment have been engineered for maximum durability to avoid the significant costs and labor associated with redesign and production. Thanks to 3D printing technology, companies can now refurbish any tool at any given time, not limited to only those which have been discarded and deemed unsuitable.

Low Cost

Traditional methods of producing injection molds are typically expensive and time-consuming, as they require precision machinery and expertise from the moldmaker. On the other hand, 3D printing offers a more cost-effective alternative for mold production.

Directly printing molds from a 3D printer can be suitable for low-volume parts (ranging from up to 100 to up to 10,000+, depending on the material) and can cost up to 90% less than metal molds. Plastic 3D printing emerges as the preferred mold manufacturing method when short lead times and low costs are key considerations.

According to reports, 3D printing molds can save up to 80% of costs compared to traditional technologies. They are much faster and cheaper than traditional metal mold production. Multiple mold versions can be printed simultaneously, offering higher application options and making them suitable for outsourcing manufacturers. This internal solution prevents data leakage and protects intellectual property rights, ensuring that the injection molded parts maintain the same quality.

3D printing requires fewer steps than machining, with an average of only six working days needed to complete the mold and part. In fact, mold manufacturing can be completed in as little as a few hours, making the process fast and efficient.

Complex injection molds can now be 3D printed using dissolvable resins, plastic (or polymer) 3D printers, and durable, temperature-resistant materials. This advancement allows companies to produce their own molds in-house or easily procure them from service providers.

What are the Disadvantages of 3D Printing Plastic Molds?

Plastic molds usually exhibit lower thermal conductivity compared to metal molds, leading to extended cooling times for injection molded parts. Additionally, they tend to degrade quicker than their metal counterparts, often necessitating post-machining processes to achieve precise accuracy. Furthermore, plastic molds are constrained by limited size options.

What are Some Typical Examples of 3D Printing Plastic Molds?

Zetar Mold

Zetar Mold is an injection molding company based in ShangHai, China, that offers rapid mold creation and small batch injection molding services. In response to the increasing demand for low-volume production, Zetar Mold has embraced 3D printing technology to create cost-effective plastic molds for quicker production of smaller orders. Through their exploration, they discovered that Formlabs’ SLA 3D printer, paired with the company’s glass-filled resin material Rigid 10K Resin, was the ideal match for their Babyplast industrial injection molding machine.

Utilizing Formlabs, Zetar Mold is able to produce 3D-printed injection molds swiftly. Following the design phase,Zetar Mold can print and conduct post-processing on the mold within a single day. By integrating the printed part with the existing metal frame of the mold, assembly can be completed in just thirty minutes, enabling immediate commencement of the injection molding process. While each mold is typically limited to approximately 100 uses, Zetar Mold can simultaneously print multiple molds to accommodate larger order quantities.

Markforged 3D printers to produce thermoset molds. The company required a durable thermoset mold to replace the costly outsourced silicone process, capable of withstanding significant clamping forces when exposed to temperatures of up to 150°C.

Markforged successfully created a mold within approximately 60 hours using the X7 3D printer and Onyx materials, at a cost of around $240 per mold. In comparison, machined silicone molds required 144 hours to produce and incurred expenses of approximately $1,000 per mold.

Addifab

Producing prototypes using the same design and materials as the final product can significantly enhance and accelerate the prototype testing process. Addifab, a startup based in Belgium, specializes in providing 3D printed molds for injection molding.

Addifab offers a proprietary resin material for 3D printing molds that can endure injection pressures of up to 2,500 bar and melting temperatures of 450°C. Subsequently, the mold completely dissolves in an aqueous alkaline solution within 12 to 48 hours. Addifab utilizes this soluble resin to 3D print injection molds.

Wilson Sporting Goods recently employed Addifab resin on its large-format Nexa3D NXE 400 printer to efficiently produce multiple versions of injection molds for new baseball bat handles.

What are the Plastic Mold Materials?

nylon

Material characteristics: Nylon has high temperature resistance, good toughness and high strength. Compared with other materials, nylon has excellent characteristics such as high fluidity, low static electricity, low water absorption, moderate melting point and high dimensional accuracy of products.

Its fatigue resistance and toughness can also meet the needs of workpieces that require higher mechanical properties. It is an engineering plastic. Ideal material for 3D printing.
Common applications: casings and enclosures, consumer sporting goods, complex prototype plastic parts, and shape, assembly, or functional prototypes.

High performance nylon

Key attributes: Malleable, flexible material with high durability, performance and impact resistance
Common applications: Impact-resistant prototypes, jigs, fixtures, thin-wall pipes and enclosures, snaps, clips and hinges.

Imported photosensitive resin

Material characteristics: Photosensitive resin materials are widely used because of their high smoothness and durability. Parts printed with this material can be subjected to post-processing processes such as grinding, polishing, painting, spraying, electroplating, and screen printing. Its performance is similar to engineering plastic ABS. With high precision and delicate surface, it can be used not only for appearance parts, but also for structural, assembly and functional verification.

Common applications: home appliances, rapid manufacturing, prototype models, electronic products, education and scientific research, architectural models, art models, automobile manufacturing and other fields.

Conclusion

The rapidly growing and highly competitive injection molding industry, worth hundreds of billions of dollars, has prompted manufacturers to seek more efficient and cost-effective ways to stay ahead of the curve.

3D printing, also known as additive manufacturing, enables these companies to produce superior injection molding molds and tooling more quickly and affordably than traditional processes. It could be argued that 3D printing molds are revolutionizing the mold manufacturing industry.