Why Air Removal Is Crucial in LSR Processing
Trapped air in mold cavities creates voids, weak spots, and surface blemishes in finished LSR parts. Given LSR's low viscosity, air entrapment happens easily during fast fills. Vacuum systems remove atmospheric gases from the mold before and during injection. This step significantly improves part density and overall structural integrity especially in complex geometries where vents cannot fully eliminate all trapped air.
Types of Vacuum Technologies Used Today
Vacuum can be applied directly to the mold via vacuum channels or externally through chamber-based systems. Mold-integrated solutions offer faster evacuation but require careful vent design. Chamber types enclose the entire mold platen assembly for complete air removal. Each method has trade-offs regarding setup complexity, cycle time impact, and suitability for specific product categories like medical devices or automotive sealing components.
Monitoring Vacuum Levels During Production
Effective vacuum control involves maintaining negative pressure within specified ranges throughout key process phases. Sensors track absolute pressure values in real time allowing automatic adjustments if deviations occur. Logging this data helps identify trends indicating potential issues such as filter clogging or leak paths developing around ejector pins over prolonged use cycles.
Best Practices for Maintaining Clean Vacuum Paths
Oil-laden vapors from some LSR formulations can contaminate vacuum pumps over time. Installing inline filters protects downstream equipment and extends service intervals. Regular cleaning of mold vent areas prevents residue buildup that restricts airflow. Scheduled inspection of vacuum lines identifies loose fittings or cracked O-rings before they cause process disruptions affecting multiple consecutive shots.