Meaning
Surface degradation mechanism occurs when two materials move against each other under an applied load. Managing sliding friction wear is essential for the longevity of moving mould components like ejector pins and slides. The process involves the gradual removal of material from the contact interface.
Material Interaction
Hardness and surface finish of the mating parts determine the rate of damage. When sliding friction wear occurs between two similar metals, the risk of galling and seizing increases. This is why mould designers often use dissimilar materials or apply specialized coatings to the moving parts.
Friction generates heat which can further accelerate the breakdown of the surfaces.
Lubrication Necessity
Thin films of grease or oil reduce the direct contact between the metal asperities. Because sliding friction wear is a constant threat in high speed moulding cycles, automatic lubrication systems are often employed. These systems ensure that a fresh layer of lubricant is present on every stroke.
Without proper maintenance, the friction increases until the components bind and stall the press. The choice of lubricant must be compatible with the plastic resin to avoid part contamination or stress cracking. Graphite or molybdenum based coatings provide a dry alternative for cleanroom environments.
Regular inspection of the wear patterns allows for the replacement of components before a catastrophic failure occurs.
Mould Longevity
Consistent protection of the sliding surfaces ensures the tool remains in production for its intended lifespan. A well maintained system prevents the need for expensive toolroom repairs. Reliable operation supports the overall efficiency of the plant.
