Guangming Group will discuss today the key influencing factors of powder metallurgy molding

1 Powder characteristics

The particle size and distribution, shape, loose density, flowability, compressibility, and other characteristics of the powder directly affect the molding effect. For example, powders with finer particle size have a larger specific surface area, stronger bonding between particles, and higher strength of the formed body. However, their flowability is poor, which can easily lead to uneven filling of the mold; Spherical powder has good flowability and is easy to fill molds, but the meshing force between particles is weak and the strength of the body is relatively low; Irregular shaped powders (such as needle like or flake like) have poor flowability, but the particles are tightly interlocked and the strength of the body is relatively high.

2 Forming process parameters

The process parameters such as forming pressure, pressurization speed, holding time, and forming temperature are the key factors determining the density, strength, and dimensional accuracy of the billet. The higher the molding pressure, the higher the densification degree and strength of the billet, but excessive pressure may cause excessive deformation of powder particles, mold damage, or cracking of the billet; Excessive pressurization speed can cause the air inside the powder to be unable to be expelled in a timely manner, forming pores and affecting the quality of the billet; Insufficient holding time can lead to uneven density of the billet, while prolonged holding time can reduce production efficiency; For methods such as hot pressing and injection molding, the molding temperature directly affects the flowability of the powder, the properties of the binder, and the bonding effect between particles.

3 Mold Design and Materials

The structural design, dimensional accuracy, surface roughness, wear resistance, strength and other characteristics of the mold material are crucial to the quality of the formed blank. Unreasonable mold structure design may lead to difficulties in powder filling, poor demolding, or defects such as material shortage and deformation in the blank body; The dimensional accuracy and surface roughness of the mold directly determine the dimensional accuracy and surface quality of the blank; The material of the mold should be selected based on the hardness and forming pressure of the molding material to ensure that the mold has sufficient wear resistance and service life (such as commonly used mold materials including Cr12MoV, W18Cr4V and other alloy tool steels).

Selection and proportion of 4 additives

To improve the formability of powders, appropriate additives such as binders, lubricants, plasticizers, etc. are usually added to the powder. The type and proportion of additives should be reasonably selected according to the characteristics of the powder and the molding method. For example, lubricants can reduce the friction between powder particles and the adhesion between the powder and the mold, improve flowability and demolding, but excessive addition can reduce the strength of the green body and subsequent sintering performance; Adhesive can improve the strength of the green body, facilitate molding and handling, but it needs to be completely removed during subsequent degreasing or sintering processes, otherwise it will affect the quality of the finished product.

Powder metallurgy, metal injection molding, powder metallurgy gears

Guangming Group focuses on the research and development of metal forming technology and wear-resistant materials. Its main products include metal compression molding and injection molding powder metallurgy products. The company has a team of high-quality talents, with the founding team originating from the Guangzhou Nonferrous Metals Research Institute, a directly affiliated national and ministerial level scientific research institution. It has rich industry experience and research and development capabilities, providing a continuous source of innovation power for the company's development. The company has successively obtained 5 invention patents and more than 30 utility model patents. It has passed the IATF16949 quality management system, ISO9001-2015 quality management system, ISO14001 environmental management system, intellectual property management system, and obtained international trademark certification. It is an innovative enterprise in Guangdong Province, a small giant enterprise in science and technology in Guangzhou, a member of the Guangdong Powder Metallurgy Industry Technology Innovation Alliance, and an initiator of the Guangzhou Advanced Powder Metallurgy Cluster Promotion Center