The unvulcanized O-ring rubber is a viscous fluid under high temperature and pressure. When it comes to the molding and vulcanization stage, the rubber quickly fills the mold cavity, and the excess part (in order to prevent the lack of rubber, the rubber filled in the cavity must be Keep a certain amount of excess) overflow and vulcanize, and overflow glue (also called waste edge, flash edge) is formed. Once the overflow is formed, in order to make the appearance neat and beautiful, it must be removed. This process is commonly called trimming. The requirements for trimming are precise size and neat appearance. In actual production. The trimming of products is often time-consuming and labor-consuming. For products with strict requirements, the slightest carelessness in trimming may lead to scrap, and it must be treated with caution. Generally speaking, the smaller the size of the product, the more complex the configuration, the more difficult it is to trim, and the more waste. The trimming of O-rings is divided into three categories: manual, mechanical and frozen:

　　 1. Manual trimming. The operator holds the tool and gradually repairs the overflow along the outer edge of the product. This is the most primitive method. The efficiency is low and the quality is difficult to guarantee. Especially for the O-rings with small size and high precision requirements, it is difficult to be thorough and clean, and it is easy to damage the connection between the product body and the overflow edge. Tooth marks and nicks are often left, leaving behind problems such as oil leakage and air leakage that affect the seal. In addition. The dependence of manual trimming on operational proficiency is also prominent.

　　 2. Mechanical trimming. In order to improve efficiency and quality, mechanical trimming appeared. The most common one is a dedicated electric trimming machine with a rotating blade. The blade used must match the height of the product size. If the inner and outer edges of the product have overflow. It can be designed as double-edged and multi-edged. To achieve one-time completion. The machining accuracy of mechanical trimming exceeds that of manual trimming, and the efficiency is also doubled. Especially for a multi-cavity product with one mold, a matching tool can be designed according to the arrangement and distribution of the product. After the product is out of the mold. The whole page can be put on, and the punching can be completed at one time. With the cooperation of heating, dozens of them can be repaired at a time. The key is that the punching temperature must be controlled well to prevent adhesion after being too high.

　　 3. Frozen trimming. The vulcanized finished product and waste edges are removed under freezing conditions. The technology is made by Japan’s Showa carbonated frozen trimming and has also undergone several generations of improvements. It is becoming more mature and perfect, and the work efficiency and processing quality have been significantly improved.