Abstract: A gas injection technique of injecting an inert gas (e.g., nitrogen gas) into a molten resin in a cavity, involves utilizing the strokes of reciprocation of a piston in the compression cylinder are used in a series mode, to perform a two-stage compression within the same cylinder, thereby providing a high-pressure gas. The method can also include establishing a relationship or pattern of the amount of movement of the piston with the speed of movement of the piston established to provide optimum control of the relationship between the pressure generated and piston stroke, and quantity of gas injected. The injecting gas pressure can be detected, to control a hold pressure, or the relationship between a piston stroke and generated pressure, so as to obtain optimal injecting pressure during the injection molding operation.

Abstract: A method and an apparatus for automatic quantitative measurement of textures by image analysis for measuring textures of a material containing various optically anisotropic textures. An image of the material is divided into a plurality of sections and brightness of each section is classified into a plurality of stages to be stored as gray levels of the sections or pixels. Image patterns of the textures are recognized on the basis of gray level variations observed before and after a mask movement, and the textures of the material are determined according to predetermined criteria.