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What are the edge trimming methods for rubber O-rings?

During the vulcanization process of rubber O-rings produced by molding, the rubber material quickly fills the entire mold cavity as the filled material requires a certain amount of interference. The excess rubber material flows along the parting line, resulting in varying thickness of the rubber edges in the inner and outer diameters.Since rubber O-rings require strict quality and appearance control due to their sealing function, even small rubber edges can potentially affect the overall sealing performance. Therefore, after vulcanization, the finished products need to undergo edge trimming to remove these excess rubber edges. This process is called edge trimming. However, generally speaking, the smaller the size and the more complex the configuration, the higher the difficulty and the more time and labor-consuming it becomes.

There are two methods for trimming molded rubber O-rings, namely manual trimming and mechanical trimming.Manual trimming is the traditional method, where excess rubber edges are gradually trimmed off along the outer edge of the product using hand tools. It requires a high level of skill to minimize product scrap rate. Manual trimming has low investment costs but low efficiency and quality, making it suitable for small batch production.There are two methods of mechanical trimming: grinding with a grinding wheel or sandpaper, and low-temperature cryogenic trimming.Currently, there are five forms of cryogenic trimming: vibration cryogenic trimming, swing or jiggle cryogenic trimming, rotary drum cryogenic trimming, brush grinding cryogenic trimming, and shot blasting cryogenic trimming.