Although the advantages of metal 3D printed molds have been well-documented and have been proposed many times, their application has been slow. This is partly due to initial concerns about material properties, partly due to the market’s lack of understanding of the specific costs and product life cycle value associated with 3D printing technology, but more importantly, there is a lack of expertise in how to apply 3D printing technology and integrate it into factories.
The gradual development of conformal cooling
Pressures and challenges
Calculating the value of investment
Mold manufacturers are often under great pressure from customers to manufacture molds at the lowest price. In addition, while 3D printed mold inserts can bring huge benefits in terms of delivery time, quality and productivity, the manufacturing process usually results in additional manufacturing costs for each 3D printed insert. Therefore, mold manufacturers must accurately calculate the value of the additional investment and prove it to the end customer.
Integration with conventional mold manufacturing processes
The final factor limiting the application of metal 3D printing technology in the mold field is the lack of solutions to seamlessly integrate it into conventional production lines, which is also a key challenge for the application of 3D printing in mold manufacturing.
Because in the field of mold manufacturing, additively manufactured inserts need to undergo later CNC machining to obtain the high surface quality required by the mold, the seamless integration of metal 3D printing technology and traditional processing technology is imperative. In the integrated solution, not only should the software that takes into account all manufacturing stages be included, but also a full set of solutions should be provided to combine multiple elements such as 3D printing equipment, materials, CNC machining, fixtures, and automation solutions to form an effective manufacturing ecosystem, thereby improving operability and reducing costs and complexity.
GS processing solutions have targeted this pain point. GS combines years of mold application and metal additive manufacturing expertise to develop a complete solution for mold manufacturers from software to final processing.
Challenges of 3D printing technology itself
Powder bed-based selective laser melting metal 3D printing technology (LPBF) is often used to process conformal cooling molds. The surface finish of these molds is critical because they will determine the appearance of the final injection molded part. Therefore, it is crucial to have a very stable printing process when 3D printing mold inserts to produce high-density parts to achieve a perfect surface finish after post-processing. These are the most challenging requirements of 3D printing technology itself.
Another challenge for mold applications is related to the materials that the additive manufacturing process can handle. Powder bed-based selective laser melting metal 3D printing technology (LPBF) is essentially a welding process. The materials commonly used in molds that are hardened by quenching are not suitable for processing by 3D printing in most cases due to poor welding performance. In 3D printing mold manufacturing, metal materials that are not used for mold manufacturing but can meet the needs of the mold are often used. The most common material is maraging steel.
Metal powder suppliers are researching new materials to meet the specific needs of molds (hardness, corrosion resistance, etc.) while still achieving high-quality 3D printing.
Innovative solutions unlock the potential of 3D printing
Hybrid molds
While many companies have already benefited from the efficiency gains of conformal cooling, some innovative “hybrid parts” have yet to be created from an economic perspective, especially for parts that require a lot of material, as the price of additive manufacturing is inherently related to the amount of material to be printed.
To overcome these challenges and effectively integrate 3D printing technology into the mold processing process, manufacturers can optimize the manufacturing economics of these mold inserts by pre-processing “preforms” and then using additive manufacturing technology to build parts with their additive manufacturing characteristics.
GS Processing Solutions and its partner 3D Systems have developed a unique “hybrid part” manufacturing solution that combines subtractive and additive manufacturing technologies to enable high-precision 3D printing on preform molds in an automated manner.
Conformal cooling applications
Injection molds
In the past few years, the application and research of metal 3D printing technology in the field of mold manufacturing have focused on the advantages of conformal cooling channel manufacturing. Typical advantages include reducing the injection molding cycle of injection molds. The optimization of cooling channel design achieved by metal additive manufacturing technology has released the potential to reduce mold cooling time, which has been generally recognized. But this is not the only advantage of 3D printing technology in improving mold cooling performance.
The quality of plastic parts is related to injection molds, especially how to achieve uniform cooling and eliminate hot spots. The impact on the quality of the final plastic part is great. The main purpose of designing conformal cooling channels is to obtain a constant temperature gradient to avoid uneven shrinkage. This allows for a more repeatable process and more predictable part deformation after the injection process, while also reducing the need for mechanical tool adjustments that are usually required to compensate for deformation. The need for mechanical adjustments commonly seen in the development phase is eliminated, thereby reducing prototype iterations and accelerating time to market.
High-pressure die casting molds
Although most mold users of metal 3D printing technology are in the field of injection molds, the application of 3D printing conformal cooling technology has attracted the interest of high-pressure die casting companies.
The spraying process in the high pressure die casting process has two main purposes: lubrication to improve demolding, and cooling as a spraying medium. The trend in industry is to try to reduce or eliminate the spraying step, and the use of conformal cooling design is to reduce the need for spraying, extend the life of the mold and maintain the quality of the casting. The surface quality of the casting is related to the surface quality of the mold.
Whether it is injection molding or high pressure die casting, the combination of conformal cooling design and additive manufacturing generally simplifies the mold design. By reducing the number of parts that need to be assembled (called assembly reinforcement), the need for seals is eliminated or reduced. All injection molding shops have witnessed the consequences of seal failure and are very familiar with downtime related to cooling leaks.
At present, metal 3D printing technology has matured for conformal cooling mold manufacturing in the opinion of injection molding and high pressure die casting companies that use 3D printed mold inserts. We will increasingly see metal 3D printing no longer just used in the prototyping department, but in the production environment. Nevertheless, investment decisions in the industrial field are long-term and based on thorough investment and return thinking. In this regard, GS Processing Solutions develops complete solutions that improve the metal additive manufacturing ecosystem and support mold manufacturing with solid technical expertise.
