In all silicone rubber products, in addition to the mos […]
In all silicone rubber products, in addition to the most common tires, the other is the O-ring (there is also a 0-ream), which has the basic characteristics of shock absorption, sealing, and wear resistance. Depending on the material, it can also have oil and oil resistance. Chemical and other properties are often used in fields such as excavators, automobiles, instrumentation, construction machinery, etc.
The most basic requirement for measuring the quality of a sealing ring is: whether there is burr (flash), because only zero burr can ensure the sealing performance of the O-ring. Today we are going to talk about how the burr is produced and how to do it. Zero burr O-ring
The generation of burrs often occurs during compression and vulcanization. At this time, the rubber material will fill the entire cavity of the mold. Since the filled rubber material must have a sufficient amount, the excess rubber material will flow out along the parting surface at this time. Edges with different thicknesses between the inner diameter and outer diameter. Such edges are called burrs.
There are two common trimming methods: manual trimming and mechanical trimming
1. Manual trimming
This method is the most primitive and traditional, that is, manually use the cutter to remove the burrs on the inner and outer edges of the ring. The quality of this trimming method depends on the experience of the workers, the efficiency is low, and the scrap rate is high, so it is only suitable for small batches of zero. Processing of burr O-rings
2. There are two types of mechanical edging: grinding wheel edging and low-temperature freezing edging
Compared with manual trimming, the grinding wheel sandpaper edging has a corresponding improvement in efficiency and quality. The specific method is to put the vulcanized O-ring on the sand rod or nylon rod with the same inner diameter and use the motor to drive it. Rotate at high speed, and then rub the outer circle of the O-ring with sandpaper or a grinding wheel to achieve trimming, but the accuracy is not high. The rough grinding surface is the disadvantage of this trimming method.
The other is low-temperature freezing edge removal. This method originated from Japan and is also a kind of mechanical trimming. The difference is that it works in a frozen environment through: vibration, swing or shaking, drum, brushing and shot blasting. , Five different forms to achieve zero burr O-rings,
The specific principle is that in a low-temperature freezing environment, the thin burrs of the O-ring change from elastic state to glass state (hardened and brittle) due to freezing, but the product itself still has a certain degree of elasticity, and then operates with vibration (or other Five forms), there is a collision between the product and the product, the product and the abrasive produce abrasion, the product and the shot blast produce an impact, then the thin burrs will be broken, and then fall off, and finally reach the trimming The product will restore its original performance at room temperature afterwards. This method has high production efficiency, but the effect of edge removal on the inner ring is poor.
Well, I will share the knowledge about zero-fray O-rings for the time being. Manufacturers should choose one or more trimming methods reasonably according to their actual conditions.
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