Injection Mold Qualification Protocol and Tooling Steel Selection Criteria
Tool steel selection and scientific qualification protocols dictate mold life, cycle efficiency, and dimensional capability under continuous production.
Galling
Meaning
Surface damage occurring between sliding solids, characterized by microscopic welding and tearing of material. Galling typically involves the transfer of metal from one surface to another during high-pressure contact without sufficient lubrication. It results in roughened textures and increased friction that can eventually lead to the total seizure of mechanical components.
Material Interaction
Friction under heavy loads causes the protective oxide layers on metal surfaces to break down. Once the bare metal makes contact, galling occurs as atomic bonds form across the interface and pull fragments away from the base. Hardness and crystal structure influence the susceptibility of different alloys to this type of adhesive wear.
Stainless steel and titanium are particularly prone to this condition.
Tooling Impact
Moving parts in injection molds or stamping dies face risks when cycles occur at high speeds. Severe galling can ruin expensive inserts and lead to unscheduled downtime for emergency repairs.
Maintenance Requirement
Regular inspection of slides and pins identifies the early stages of wear before catastrophic failure happens. Polishing out the localized damage caused by galling restores the surface finish but may alter the dimensions of the tool. Consistent application of high-temperature lubricants provides a barrier that prevents the direct metal contact responsible for the damage.