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Three Types of Wear of Screw and Barrel for Pipe Machine
The manufacturer of Screw and Barrel for Pipe Machine tells you that the screw and barrel are the key parts in the injection molding machine, which can be called the "heart". Because of their good wear resistance and high hardness, their service life is relatively long, but They will also wear out during high-speed operation for a long time. Today we will explain the three types of wear of Screw and Barrel for Pipe Machine. I hope you can pay attention to it during use.
The barrel is generally made of high compressive strength and corrosion-resistant lining alloy steel or alloy steel, while the screw is generally made of corrosion-resistant and high-temperature-resistant alloy steel. The barrel and screw cooperate with each other to realize the crushing, melting, exhausting, compacting and conveying of raw materials.
The screw rotates at high speed in the barrel, and wear and tear will occur over time. There are many places where wear occurs, and it can occur on the screw edge, or on the surface of the barrel, or both. The manufacturer of Screw and Barrel for Pipe Machine tells you that in order to reduce the wear of the barrel and screw, we need to know three types of wear first.
1. Adhesive wear
Adhesive wear occurs when the surface of the flight and the inner surface of the barrel come into contact. When the surfaces are in brief contact, high stresses are unavoidable in the event of a rupture due to the fact that the two are welded together.
How to identify adhesive wear? One of the more obvious features is the burr at the end of the screw edge. Scratches in the build-up material or disappearance of the build-up material from the top of the flights are also indications of adhesive wear on the barrel and screw. In addition, you can also check whether the barrel is scratched.
2. Abrasive wear
This is a more common type of wear on the barrel and screw of an injection molding machine. Abrasive wear is very unlikely to occur when unfilled or when processing low-viscosity polymers. When the raw material is conveyed to the barrel along the screw and is squeezed on the barrel wall, the shearing force will cause the raw material to wear the screw edge and the barrel wall.
When the injection molding machine is processing resin materials containing fillers, additives, pollutants, or high-viscosity polymers, abrasive wear is more likely to occur. The harder material of the raw material will tend to remove material from the softer surface, so the material of the screw is generally a harder and wear-resistant alloy.
The manufacturer of Screw and Barrel for Pipe Machine tells you that when processing glass and mineral-filled resin materials, it will also cause abrasive wear at the root of the screw. This wear generally occurs in the second half of the rubber channel, the additives are wetted, and the molten plastic Before mixing.
3. Generally, corrosion and wear are formed by chemical attack, which gradually destroys the materials of the barrel and screw. Most of the atoms on the surface of the metal are oxidized, destroying the entire surface. Once the metal surface is eroded, it will accelerate the wear of the barrel and screw. When processing PVC or fluoropolymer materials, corrosion and wear are relatively easy to occur, especially these materials will corrode parts with iron as the main substrate.
Generally speaking, regardless of whether polymers or metal particles are processed, the harder the raw material is, the faster the barrel and screw will wear, and the original gap distance will increase. Once the gap increases, the melting efficiency of the raw material will decrease instead. Due to the decline in melting efficiency, many operators will increase the speed of the screw, increase the temperature of the barrel, and increase the back pressure, so as to make up for the problem of the decline in melting efficiency.
The manufacturer of Screw and Barrel for Pipe Machine tells you that many customers hope to have a scientific method to reduce the wear of the screw and barrel, but this is not an easy task. proceed.