What are the different ways to trim the edge of a sealing ring?

The trimming of sealing rings is a key process in the production of rubber sealing rings, aiming to remove burrs and flash from the edges of the products after vulcanization, and improve dimensional accuracy and appearance quality. The following are the common trimming methods for sealing rings and their characteristics:

I. Mechanical edge trimming

Punching and trimming

Principle: Flash is directly removed by using a stamping die, which is suitable for sealing rings with relatively low hardness (such as silicone rubber and EPDM).

Advantages: High efficiency, low cost, suitable for mass production.

Disadvantages: The mold has high precision requirements and is prone to generating debris.

Application: Standard parts such as O-rings and Y-rings.

Cutting and trimming

Principle: Flash is cut by rotating the tool (such as a milling cutter), which is suitable for materials with high hardness (such as fluororubber).

Advantages: High precision, capable of handling complex shapes.

Disadvantages: The equipment cost is high and the cutting tools need to be replaced regularly.

Application: Automotive engine seals, hydraulic seals.

Rolling and trimming

Principle: The sealing ring and abrasive materials (such as ceramic particles) are placed in the drum and rolled to remove flash through friction.

Advantages: Low cost, suitable for small batches or irregular-shaped parts.

Disadvantages: Low efficiency and possible damage to the surface of the sealing ring.

Application: Medical seals, small-sized O-rings.

Ii. Frozen edge trimming

Principle: Place the sealing ring in liquid nitrogen and freeze it to the embrittlement temperature (-196℃). Use high-speed shot blasting (such as plastic particles) to impact the flash and make it fall off.

Advantages: No stress residue, suitable for precision parts; It can handle complex structures.

Disadvantages: The equipment is expensive and the operating cost is high.

Application: Aerospace seals, sealing rings for high-end electronic equipment.

Iii. Enthusiastic trimming of the edges

Principle: Utilizing high-temperature tools or laser cutting for flash, it is suitable for thermoplastic materials such as TPU.

Advantages: No mechanical stress and smooth cut surface.

Disadvantage: Temperature control is required to prevent material deformation.

Application: Food-grade sealing rings, transparent sealing parts.

Four. Hand trimming

Principle: Remove burrs manually by using tools or sandpaper.

Advantages: Strong flexibility, suitable for small-batch or high-precision requirements.

Disadvantages: Low efficiency and quality reliance on workers' skills.

Application: Sample production, customized sealing parts.

V. Other auxiliary edge trimming techniques

Vibration trimming

Combining vibration and abrasives, it is suitable for batch processing of small sealing rings.

Water jet trimming

The flash is cut by high-pressure water flow and is suitable for materials that are prone to deformation.

Plasma trimming

Flash removal by plasma is suitable for ultra-precision seals.

Quality inspection after trimming

Visual inspection: Flash residue, surface scratches.

Dimensional measurement: Ensure that the dimensions after trimming meet the tolerance requirements.

Performance tests: such as sealing performance, compression set, etc.

Summary

Mass production: Mechanical edge trimming (punching, cutting) or cryogenic edge trimming is preferred.

For small batches or irregular-shaped parts: Rolling and grinding edge trimming or hand edge trimming can be considered.

Precision requirements: Cold trimming or hot trimming is more suitable.

Comprehensively choosing the trimming method based on the material properties, product structure and production scale can effectively improve the quality and production efficiency of the sealing ring.

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