Get an insight into how the binder jet 3D printing technology achieves the outstanding performance of cemented carbide tools!

Cemented carbide cutting tool is a kind of finishing alloy with ultrafine particle tungsten carbide as the main raw material and metal elements such as cobalt, yttrium or other refractory carbide powder as auxiliary materials. It has high hardness, high strength, good toughness and resistance. A series of excellent properties such as grinding, heat resistance, corrosion resistance, etc., so it is suitable for use in CNC machine tools.Recently, according to the market observation of 3D Science Valley,3D printingThe technology has achieved a more complex structure and a hard alloy tool with a cooling internal runner.

3D printingTechnology and Tool Manufacturing

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More refined and more complex

Challenge better

Tungsten carbide is the most widely used high speed machining (HSM) tool material produced by powder metallurgy. It consists of hard carbide (usually tungsten carbide WC) particles and a softer metal binder. Currently, there are hundreds of WC-based tungsten carbides with different compositions, most of which use cobalt (Co) as a binder. Nickel (Ni) and chromium (Cr) are also commonly used binder elements, and other additives can be added. Some alloying elements.

The severe conditions of modern machining operations require cutting tools to have excellent hardness and fracture toughness, as well as high requirements for wear resistance, surface quality and dimensional tolerances. Hard metals such as tungsten carbide cobalt (WC-Co) and tool steels such as M2 are ideal for such applications because they have excellent and balanced hardness/fracture toughness, high temperature resistance and wear resistance, but may be difficult to manufacture. Even for some 3D printing technologies, it is full of challenges.

Traditional processing technology usually manufactures large-size cemented carbide workpieces or carbide workpieces (such as end mills and drill holders) with high aspect ratios by uniformly pressing tungsten carbide powder in a flexible bag. Although the production cycle of the pressure equalization method is longer than that of the molding method, the manufacturing cost of the tool is lower, so this method is more suitable for small batch production.

Cemented carbide workpieces can also be formed by extrusion or injection molding. The extrusion process is more suitable for the mass production of axisymmetrically shaped workpieces, while the injection molding process is usually used for the mass production of complex shaped workpieces. In both molding methods, the grades of tungsten carbide powder are suspended in an organic binder, which imparts uniformity to the tungsten carbide mixture such as toothpaste. The mixture is then extruded or molded through a hole into a mold cavity. The characteristics of tungsten carbide powder grade determine the optimal ratio of powder to binder in the mixture, and have an important influence on the flow of the mixture through the extrusion orifice or into the mold cavity.

After molding, equalizing, extruding or injection molding the workpiece, the organic binder needs to be removed from the workpiece before the final sintering stage. Sintering removes the pores in the workpiece and makes it completely (or substantially) dense. During sintering, the metal bond in the press-formed workpiece becomes liquid, but the workpiece can still maintain its shape under the combined action of capillary force and particle contact.

After sintering, the geometry of the workpiece remains unchanged, but the size is reduced. In order to obtain the required workpiece size after sintering, the shrinkage rate needs to be considered when designing the tool. When designing the grade of tungsten carbide powder used to manufacture each tool, it must be ensured that it has the correct shrinkage rate when pressed under the appropriate pressure.

Familiar with Binder Jetting3D printingIt is not difficult for technical professionals to find that the degreasing, sintering process and binder spraying metal in the process of cemented carbide workpieces manufactured by the traditional injection molding process3D printingThe post-processing process required by the technology is consistent.

Then think according to this logic, Binder Jetting Binder Jetting metal3D printingCan the technology replace the metal injection molding process or powder metallurgy process to achieve a cemented carbide workpiece that does not require a mold and has a more complex internal structure?

Flexible custom parameter settings

According to the market observation of 3D Science Valley: TECNALIA of Spain uses its scientific research knowledge to help the company achieve greater success through disruptive adhesive jetting technology.

3D printingTechnical Carbide Tools © exone

Binder jet additive manufacturing overcomes the limitations of additive manufacturing processes that require support. It can be used to process hard metals and tool steels that are required but difficult to process. The design freedom enables cooling channels to improve performance to be directly integrated into the design. middle.

3D printingTechnical Carbide Tools © exone

In this case, the ExOne Innovent machine can flexibly customize the parameter settings, combined with the TECNALIA team’s process and material expertise, and customize the attributes for the application, thereby achieving a breakthrough and delivering the final part with the required attributes.

3D printingTechnical carbide blade © exone

After sintering, parts with a density comparable to conventionally manufactured commercial parts were obtained. In addition, the hardness and fracture toughness of the material are also comparable.

3D printingRelease the freedom of tool manufacturing

Use 3DP adhesive spray3D printingtechnologyThe production of cemented carbide tools has already existed at home and abroad.Internationally, earlier, researchers at the Fraunhofer Institute in Germany successfully used 3DP adhesive jets3D printingtechnologyProduction of cemented carbide tools. By printing cemented carbide powder with 3DP, the institute can easily create complex designs. In this process, powder particles of ceramic hard materials, including tungsten carbide particles, are printed and bonded by layers of bonding 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.

Not only the 3DP technology used by the Fraunhofer Institute, another3D printingThe technology LPBF is also frequently used in tool manufacturing.Gomat also uses LPBF metal3D printingTechnology and machining techniques are used to manufacture milling cutters.The part of the cutter body with dense flutes in the milling cutter is made of metal3D printingTechnically manufactured customized non-standard products, the handle part is a standard product mass-produced through mechanical processing technology.

Tool manufacturing company actively explores3D printingTechnology Application and Tool Manufacturing
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In addition, Mapa also passed3D printingThe technology creates a complex spiral cooling channel for the QTD series of tools, thereby improving the heat transfer capacity of the coolant during the flow of the coolant to the top of the drill bit. Mapa’s drills have a longer life and faster operation speed than previous drills.

Whether 3DP technology is used in the manufacture of cemented carbide tools or LPBF technology is used in the manufacture of metal cutter heads and tool holders,3D printingTechnology occupies an increasingly important position in the manufacturing of cutting tools.

(Editor in charge: admin)