Injection Molding Mold Structure Composition and Full Lifecycle Maintenance Guide
Release time:
2025-11-26
Injection molds are often referred to as the “mother of industry,” as their structural integrity and maintenance level directly determine production efficiency and product quality; it is a widely held industry consensus that “molds account for 70% of success, while process control accounts for the remaining 30%.” A standard injection mold consists of eight core components, each with specific functions and key maintenance considerations, as outlined below:
Molded parts (Core inserts, cavities, and other components) are the heart of the mold and directly determine the final product geometry. During maintenance, particular attention should be paid to surface finish: for mirror-finish or electroplated molds, cleaning must be performed with clean cotton swabs, and scrubbing with cloths or hard objects is strictly prohibited. For textured-core inserts, the integrity of the texture pattern must be inspected regularly, and any signs of wear应及时补纹 (immediately repaired or re-textured). One home-appliance manufacturer, by implementing a scheduled inspection regime for molded parts, extended the service life of its molds from 500,000 cycles to 800,000 cycles.
Casting system (Main runners, sub-runners, gates, etc.) are prone to accumulation of solidified material, necessitating thorough cleaning every 100,000 mold cycles. For hot-runner molds, melt temperature fluctuations must be controlled within ±3°C, dead-zone areas should be minimized, and material degradation and contamination must be prevented. A medical-device manufacturer using hot-runner molds to produce syringes once experienced black-spot defects due to untimely hot-runner cleaning; after implementing corrective measures—cleaning the hot runner every 50,000 mold cycles—the defect rate was reduced to zero.
Demolding mechanism Lubrication of ejector pins, push rods, and similar components is critical. During production, lubricant must be applied to all moving parts every 12 hours; in hot-mold operations, high-temperature grease must be used. When the machine is shut down for an extended period, anti-rust oil should be evenly sprayed onto the ejection mechanism, and a 1–3 cm gap should be maintained between the mold halves to prevent rusting. One electronics manufacturer once experienced a jamming failure due to insufficient lubrication of the ejector pins, resulting in damage to the mold and direct economic losses of RMB 80,000.
Daily mold maintenance also requires attention to the following: the parting line should be wiped every 5–8 hours to prevent adhesive filaments and foreign objects from causing damage; the mold temperature control system’s water lines must be regularly inspected for blockages to avoid leaks and corrosion; and the core-pulling mechanism’s inclined guide posts and slides should be periodically checked for wear, with aged components such as springs and bolts replaced as needed. Establishing a comprehensive mold maintenance record that documents each maintenance task, parts replacements, and troubleshooting actions can reduce mold maintenance costs by more than 20%.
