News

Jo Mar 12, 2025

At present, fabrication of micro-scale components and devices is one of the major technologies with considerable potential, and it is of great importance to make manufacturing processes suitable for their medium and large-scale production.

In the last decade, there has been an increasing demand for micro-sized components and their microstructures, which has led to the introduction of micro-injection molding technology to fluid control techniques and medical tools. The most promising process of this technology is micro powder injection molding (μPIM), a product manufacturing technology for producing small size components of complex shapes in large quantities.

However, the μPIM process suffers from several difficulties, unlike the PIM process. In the μPIM process, there is a high demand for powder. For example, the fluidity of raw material depends on the type and size distribution of powder, and the size change after debinding depends on the friction force between particles. In addition, the lubricity of the binder depends on the particle surface conditions, and the debinding rate also depends on the particle morphology, particle size, etc. Raw material powder should be less than 5㎛ in size. The composition of the binder used for mixing raw materials has a great influence on the product's molding and demolding. That is, it needs to have high viscosity. The temperature should be well controlled at the time of debinding of various mixed binders to eliminate cracking during sintering of products and to ensure dimensional accuracy after sintering.

Ri Un Sim, a researcher at the Faculty of Materials Science and Technology, while preparing a 800㎛ micro-gear from 1Cr18Ni9 stainless steel spray powder using μPIM technique, has analyzed the effects of injection temperature, injection pressure and injection speed on the formation of components.

As a result, she has found that injection molding is best at the injection temperature of 130℃, scanning pressure of 70㎫ and scanning rate of 60mm/s.