Fraunhofer uses 3DP technology to manufacture cemented carbide molds

Cemented carbide, a composite material made of fine-grained cemented carbide and cemented carbide of bonded metal, is a very hard material, often used in machinery and automotive engineering and building materials industries. Cemented carbide molds are ten times or even dozens of times the life of steel molds. Cemented carbide molds have high hardness, high strength, corrosion resistance, high temperature resistance and low expansion coefficient. Generally, tungsten-cobalt cemented carbide is used.

The hardness of the cemented carbide is too high. The conventional processing is grinding. Diamond grinding wheels are used, and fine-point grinding wheels are used for polishing. Generally, the inner hole can only be processed by electric erosion, such as electric discharge machining, or wire cutting, or even electrolytic grinding technology.

Researchers at the Fraunhofer Institute in Germany have successfully used 3DP binder jet 3D printing technology to produce cemented carbide molds. We understand that these 3D printed cemented carbide molds have greater geometric groove freedom than traditional molds, and can be made into more complex geometric shapes.

As an expert in the field of cemented carbide, the Fraunhofer Institute has used uniaxial or cold isostatic pressing dry pressing to manufacture ceramic cemented carbide molds for decades. These materials are mainly made of tungsten carbide. Despite the high reliability of these molds, the Fraunhofer Institute is still facing a problem. When it is necessary to create complex geometries, such as internal spiral or tortuous cooling ducts, the limitations of traditional manufacturing processes It appeared.

Now, with 3DP printing of cemented carbide powder, the institute can easily create complex designs. 3DP is a binder jet printing technology. In this process, powder particles of ceramic hard materials, including tungsten carbide particles, are printed and bonded by layers of adhesive materials containing cobalt, nickel or iron. This kind of adhesive material is not only the adhesive between the powder layers, but also makes the product have good mechanical properties and can produce completely dense parts, and even can selectively adjust the bending strength, toughness and hardness.

The subsequent treatment includes sintering treatment to obtain the firmness of the cemented carbide mold consistent with the traditional processing method. The Fraunhofer Institute believes that this process has a wider scope for expansion, including the uniform distribution of tungsten powder into the cemented carbide, which can be used to produce high-performance tools.
Indeed, in addition to making molds, cemented carbide is more widely used as tool materials, such as turning tools, milling cutters, planers, drill bits, boring tools, etc., for cutting cast iron, non-ferrous metals, plastics, chemical fibers, graphite, glass, etc. Stone and ordinary steel can also be used to cut difficult-to-process materials such as heat-resistant steel, stainless steel, high manganese steel, and tool steel. In the future, whether 3DP technology will be applied to the production of cemented carbide tools, perhaps it is not impossible for the production of small batches of special tools.