Why is mold die surface treatment important?

Surface treatment of mold die can significantly improve the performance and service life of molds. Through surface treatment, the physical and chemical properties of the mold surface can be improved, and its wear resistance, corrosion resistance, fatigue resistance and bite resistance can be improved.

Surface treatment methods such as grinding and polishing, sandblasting, hard chrome plating, and laser cladding can significantly improve welding quality and mold life. From mechanical treatment to composite processes, each technology is precisely working for smoother mold cavities, stronger wear resistance, and less metal resistance.

What are the common mold die surface treatment methods?

Mechanical treatment of mold die

Grinding and polishing

Use sandpaper, grinding wheel and other tools to polish the cavity surface to remove surface roughness and defects and make the surface smoother. This helps to reduce the resistance of the metal liquid flowing in the cavity, ensuring that the metal liquid can evenly fill the cavity, thereby improving the surface quality and dimensional accuracy of the welded joint. Further fine polishing can be done with polishing paste or polishing machine to make the cavity surface mirror-like, reduce the friction between the metal and the cavity surface, and reduce the occurrence of mold sticking.

Sand blasting

Sand is sprayed at high speed to impact the surface of the mold cavity, which creates tiny unevenness on the surface and increases the surface roughness. This can improve the adhesion between the molten metal and the surface of the mold cavity, facilitate exhaust, and reduce the generation of defects such as pores. At the same time, sand blasting can also eliminate the residual stress on the surface of the mold cavity and increase the fatigue life of the mold die making.

Chemical treatment

Plating treatment

Hard chrome plating: A layer of hard chrome is plated on the surface of the mold cavity. The chrome layer has the advantages of high hardness, good wear resistance, and strong corrosion resistance. It can improve the hardness and wear resistance of the mold cavity surface, reduce the wear of the mold during use, and extend the service life of the mold. At the same time, the smooth surface of the chromium layer also helps the flow and demolding of the molten metal.

Nickel plating: The nickel plating has good corrosion resistance and chemical stability, and can protect the surface of the mold cavity from the erosion of the molten metal. In addition, the nickel plating can also improve the wettability of the mold cavity surface, making it easier for the molten metal to fill the mold cavity and improve the welding quality.

Chemical conversion film treatment

A conversion film, such as phosphating film, oxide film, etc., is formed on the surface of the mold cavity by chemical methods. These conversion films can improve the corrosion resistance and wear resistance of the mold cavity surface, and at the same time can play a certain lubricating role, reducing the friction between the molten metal and the mold cavity surface. The phosphating film can form a porous protective film on the surface of the mold cavity, absorb lubricants, reduce the friction coefficient, and improve demolding performance.

Physical treatment

Physical vapor deposition (PVD)

In a vacuum environment, metal or compound is evaporated by physical methods and then deposited on the surface of the mold cavity to form a thin film. Common PVD coatings include TiN, TiC, TiAlN, etc. These coatings have the advantages of high hardness, high wear resistance, and low friction coefficient, which can significantly improve the performance of the mold cavity surface. TiN coating can improve the hardness and wear resistance of the mold cavity surface, and also has good anti-oxidation properties, which can protect the mold cavity surface at high temperatures.

Laser surface treatment

Use the high energy density of laser to treat the cavity surface, such as laser quenching, laser cladding, etc. Laser quenching can improve the hardness and wear resistance of the cavity surface, while laser cladding can clad a layer of alloy with special properties on the cavity surface to improve the performance of the cavity surface. Laser cladding can clad a layer of high hardness and high wear resistance alloy on the cavity surface to improve the service life of the mold and welding quality.

Composite treatment

Combining two or more surface treatment methods to give full play to their respective advantages and further improve the performance of the cavity surface. The cavity surface is first plated and then laser treated. This allows the cavity surface to have both the corrosion resistance and lubricity of the plating layer and the high hardness and wear resistance after laser treatment, thereby significantly improving the welding quality and the service life of the mold.