The commonly used sealing strip is made of rubber. This paper mainly introduces the production process of rubber sealing strip. The main process of rubber seals includes three parts: rubber mixing, extrusion vulcanization and post processing.
In the process of rubber refining, the formula of various raw materials and processing conditions such as temperature, pressure and time are strictly controlled by computer. Granulated or banded rubber compound is prepared. For PVC and TPE seals, suitable particle materials can be directly selected for extrusion processing.
Rubber seals are generally combined with extrusion and vulcanization processes in actual production. In the process of extrusion vulcanization, all kinds of granular or ribbon blends and skeleton materials are extruded together through the die of extruder and vulcanized at high temperature. In this process, the design, manufacture and vulcanization methods and conditions of die play a key role in the performance and quality of the product. If the die design is not reasonable, the sealing strip will be in the process. The fluctuation of pressure and cross-section during extrusion, the dead angle of runner will cause rubber burning and bad bonding through different runner materials, etc. Using computer software to simulate the flow state and digital die technology can improve die quality and shorten the die design and manufacturing cycle. Sulfur and sulfur deficiency will have adverse effects on the quality of products. In the aspect of vulcanization technology, salt bath vulcanization is seldom used because it is easy to pollute the environment. Now most factories adopt the method of microwave heating and hot air heating. By controlling the temperature, speed and pressure of each point in the production line by computer, the ideal vulcanization condition and extrusion quality can be guaranteed. According to the different installation parts of the sealing strip, some sealing strips need to be flocked, sprayed on the surface and added non-drying adhesive in the clamping part of the sealing strip. These processes can be completed online through special devices.
For PVC and TPE seals, the process needs no vulcanization, and other processes are similar to the extrusion of rubber seals. The post-processing process can be divided into three main processes: cutting, molding (joint, joint angle) and post-processing. In the cutting process, the sealing strip needs to be processed to the desired shape and size. In order to ensure its good processing accuracy and interchangeability, the use of multi-station combined processing equipment can achieve satisfactory results. In the molding process. In order to ensure precise shape, injection vulcanization is usually used. In recent years, more and more automobiles adopt combined sealing strips, which combine several sealing strips with multiple sections. The post-processing process is developing toward modularization and combination. The post-processing process includes flocking and spraying, pins and double-sided tapes with fixed sealing strips and finishing and trimming. For some high-grade cars, sensors are implanted in the post-processing, and signals are sent out when the stress reaches a certain value to control the window lift. The work of reducing motor has the function of preventing clamping. For mass-produced products, the application of streamlined production lines and robots in post-treatment processes is the trend of development.
