Company visit: PIM International, Vol.3 No. 4 December 2009, pages 43-46, 1736 words

Author: Mr Xiao Yulin, PM Consultant, China

Hunan Injection High Technology Co. Ltd. was established in Changsha in 2000 as one of China’s first commercial metal injection moulding (MIM) companies. The company was initially established under the umbrella of the Powder Metallurgy Research Institute of the Central South University, but has quickly become one of China’s leading independent MIM producers. Mr Xiao Yulin recently visited the company on behalf of PIM International and reports on the product developments and future plans.

Hunan Injection High Technology Co Ltd (HIHT) traces its short history back to 1995 when the Powder Metallurgy Research Institute at Central South University in Changsha, the capital city of Hunan Province, first took an active interest in metal injection moulding (MIM).

It was Professor Huang Baiyun, a leading powder metallurgy expert in China, and at the time President of Central South University, who set out to include MIM research at the PM institute. This early initiative was rewarded with the first PhD given to a Chinese researcher for a dissertation on MIM which was completed by Dr Li Yimin in 1998. Dr Li was then given the task of becoming General Manager of the newly established MIM company - HIHT - in 2000, and Professor Huang Baiyun was appointed president of the new company.

Dr Li has been General Manager ever since, and in 2004 he published a monograph entitled ‘Theory and Application of Metal Injection Molding’, which has become one of the most popular works of reference on MIM technology in China.

One of the advantages in setting up the new MIM company at the Powder Metallurgy Research Institute in Changsha was the ability to draw on a significant resource of highly qualified talent from the institute, and also the wide range of production engineering knowledge available from within Central South University overall.

Over the past ten years Dr Li and Professor Huang have succeeded in building up a highly professional and motivated team which has achieved well above average growth rates in the MIM sector, including an impressive growth of more than 30% per year over the last three years alone........

Further sections of this article include:

- Setting high standards in MIM production
- Innovation
- Examples of MIM products

Figures and Tables:

Fig. 1 Details of MIM components produced at HIHT for use in disposable biopsy instruments.

Fig. 2 MIM jaws produced by HIHT for use in disposable surgical instruments

Fig. 3 A selection of surgical instrument components

Fig. 4 Cross-sections of parts with engineered surface and core structures

Fig. 5 MIM parts used in a multi-functional tool weighing 220g and 122mm in length. The MIM parts are sandblasted and polished

Fig. 6 An assembled multifunction tool for the international market featuring the MIM parts shown in Fig. 4

Fig. 7 Mr Xiao Yulin (left) and Dr. Li Yimin, General Manager of Hunan Injection High Technology Co. Ltd. (right)

Fig. 8 MIM lock-cylinder parts

Fig. 9 Lock-cylinder parts made by MIM

Fig. 10 Lock-cylinder parts made by MIM

Table 1 The main materials processed by HIHT [1]. The properties strongly depend on carbon content and heat treatment [2]. The value varied depending on W contents [3]. Mechanical properties at high temperature: 600°C: σ b>400, ε>20; 800°C: σb >200, ε>35; Properties of Fe50Ni: Saturation induction: 1.51T; Coercive force: 4.826A/m, Maximum permeability: 75.21 mH/m; initial permeability: 22.38 mH/m. Corrosion rate of 316L stainless steel: <0.1g•m^-2•h^-1 in 5% NaCl solution; < 0.15g•m^-2•h^-1 in 5% HCl solution; Corrosion rate of 17-4PH stainless steel: <1.2 g•m^-2•h^-1 in 5% NaCl solution