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.

High-speed sheet metal stamping is popular because it is economical and quick means of producing intricate, accurate and durable components in large quantities. Scrap jumping up is one problem which usually occurs in high-speed stamping manufacturing processes. In this paper, the relevant factors are analyzed and studied such as the press tool, the shape and size of the stamping pieces, the structure and rigidity of pressing die, the clearance between punch and die, material properties of the blank, etc. Then ten cases are summarized that lead to scrap jumping up. For each case, corresponding solution is presented to avoid the scrap jumping up.