Already, additive manufacturing is being used extensively in the production of equipment, tools molds and dies. This includes not only the production of prototypes but also the creation of strong, durable and customized end-use parts.
One clear example of this is a recent partnership between German companies GROB-WERKE GmbH and Siegfried Hofmann GmbH, which is aimed at revolutionizing the production of aluminum particle foam molds with 3D printing. The collaboration combines GROB’s experience in additive manufacturing with Hofmann’s mold expertise for the development of more efficient and innovative solutions for the industry. We took a closer look at how GROB’s additive manufacturing technology works as well as how Hofmann is able to benefit from it in the production of particle foam tools and molds.
Demonstrator “Frisbee,” a particle foam component, that has the desired feel on the surface, thanks to the uniform porous structure of the GMP printed mold.
GROB’s Liquid Metal Printing (LMP) Technology for Aluminum Parts
In 2022, GROB, a leading manufacturer of industrial automation machines and systems, launched its first additive manufacturing machine, the GMP300. This innovative 3D printer is based on Liquid Metal Printing (LMP) technology, also known as Molten Metal Printing (MMP). The solution was developed specifically by GROB for the rapid and cost-effective production of aluminum parts.
But how exactly does Liquid Metal Printing (LMP) technology work? The GMP300 uses aluminum wire, which is cheaper and easier to handle than powders. This wire is melted and, similar to an inkjet printer, the liquid aluminum is then deposited on a heated build plate measuring 300 x 300 mm. This process allows for rapid production of the part, with a maximum printing speed of 200 cm³ per hour.
According to GROB, the resulting, finished parts are stress-free, ready for use and have excellent mechanical properties. They also require only minimal subsequent post-processing. Hofmann further notes that aluminum tools produced with LMP technology are not only lighter and more corrosion-resistant than their steel counterparts, but also allow for optimum vaporization, venting and homogeneous filling.
The GMP300 from GROB
Benefits of Additively Manufactured Particle Foam Tools Over Those Made With Traditional Manufacturing
To achieve these impressive results, GROB and Hofmann have developed a solution for the optimal production of particle foam tools by combining GROB’s LMP technology and Hofmann’s BE-AD.MACHINE particle foam molding machine. “We are particularly proud of the rapid production of the additively manufactured aluminum foam molds” says Stefan Hofmann, Managing Director of Siegfried Hofmann GmbH. “We only needed a third of the time to produce our demonstrator tool compared to its 3D printed steel counterpart.”
A GMP printed mold for a particle foaming machine, one of two half shells. It has an aluminum, porous structure and is “as printed,” only the sealing surface was post-processed.
Compared with the use of traditional manufacturing methods, the use of 3D printing has brought many advantages. Among these, Hoffman highlights shorter thermal stages and optimized material use, ultimately leading to reductions in weight, cost and production time. Another key benefit is greater design freedom, allowing molds with complex, customized geometries, such as hollow structures of almost any shape.
Finally, the process ensures the creation of dense, low-distortion tools, ensuring accuracy and reliability in industrial production. The porosity of the mold insert, up to 50%, ensures maximum evaporation of the raw material, allowing even large parts to be produced without problems.
Hofman adds that thanks to GROB’s Liquid Metal Printing process it can take as little as a week from the start of the design to the first foaming process, depending on the complexity of the project. The solution is also presented as ideal for series parts with basic surface quality requirements. Furthermore, lightweight molds produced additively could be the best solution for short-term prototype testing of materials, spraying and evaporation.
Steam chamber with GMP printed mold, also one of two sides, for installation in a particle foaming machine.
In any case, it seems clear that this collaboration is a significant step toward the widespread adoption of additive manufacturing in the particle foam industry. The partnership shows how additive manufacturing can offer faster, cheaper and lighter solutions in the sector and illustrates why it is increasingly emerging as a viable alternative to traditional methods that are often slower, more expensive and less versatile. To learn more, click HERE.
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*All Photo Credits: GROB-WERKE GmbH