Oxidation coatings were prepared on the surface of AZ31B magnesium alloy by micro-arc oxidation in the electrolytes with CoSO 4 addition varying from 0 to 0.8 g/L. The effects of different concentrations of CoSO 4 on the properties and microstructure of the coating were analysed by Scanning Electron Microscope (SEM), X-ray Photoelectron Spectroscopy (XPS), Xray Diffraction (XRD) and Electrochemical Workstation. The results revealed that the addition of different concentrations of CoSO 4 caused the voltage variation, which resulted in the changes of microstructure, phase composition and element distribution of coatings. Furthermore, it led to the improvement of coating properties. It was found that the oxidation voltage increased firstly and then decreased. Because of CoSO 4 addition, the morphology of the coating was changed. XRD patterns and XPS confirmed that Co 3 O 4 , MgO and Mg 2 SiO 4 were generated. The addition of CoSO 4 could effectively improve the hardness, corrosion resistance and thermal-shock resistance.

In injection molding processes, while the plastic is injected into the mold cavity, the displaced air leaves the mold through openings which are referred to as the venting slots. With the continuous improvements of manufacturing precision and injecting speed, the design of venting slot is becoming an important problem which influences the quality of products greatly. In this paper, five types of possible location to generate “gas-trap” were summarized based on the research and analysis of mold manufacturing and injection molding. The dimensions of venting slot, eight kinds of venting mode and their corresponding structures were presented. The principle for the design of venting system was proposed.

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This paper describes a structural design tool for punches and dies in 3D progressive dies of motor core based on association design technology. Based on the classification and 3D modeling method of punches and dies, the associated model is set up to describe the holes on plates of die set for punches and dies. The proposed tool integrates the design knowledge of progressive dies for motor core to automate the design for punches, dies and corresponding holes on plates. This design tool is constructed on a PC and integrated with SolidWorks software. We use progressive die for the motor core with rotator, stator and vice-stator as a concrete example to demonstrate the power of the design tool. The results show that it can not only improve design quality but also save both time and costs dramatically.

High-speed injection molding technology refers to the injection speed of rotating screw is about 500mm ~1000mm/s during the injection process. It is extensively used in the fabrication of thin and accurate products, for example, packing containers, CD or DVD disc-based panels, smart cards, optic fiber connecters, etc. In this paper, the advantages of high-speed injection molding technology on cost savings, product quality and productivity are presented firstly. Then the mold characteristics on strength, stiffness, precision, used material, heat treatment, the runner system, the venting system and the ejection system are illustrated. A plastic flowerpot by high-speed injection molding is selected as an example to show the high production efficiency.