Generally speaking, the service life of an injection mold is measured in “shots” or “cycles“ (injection molding cycles), rather than a fixed number of years. It is heavily influenced by factors such as mold class, steel material, plastic type, process parameters, and maintenance practices.
According to the international SPI (Society of the Plastics Industry, now PLASTICS) mold classification standards, typical expected lifespans are as follows:
- Class 101 (high-end molds): Over 1 million cycles, suitable for extremely high-volume production, such as bottle caps or automotive parts. These use hardened steels (e.g., H13) with high hardness requirements (often ≥48 HRC for cavities).
- Class 102/103 (mainstream mid-to-high-end): 500,000 cycles for Class 103. These are the most common industrial molds, often using steels like P20 or NAK80.
- Class 104 and below (low-end/prototype): Under 100,000 cycles, mostly for small-batch or trial production.
In industry experience, medium-sized injection molds typically achieve an average lifespan of 300,000–800,000 cycles. For example:
- P20 steel: approximately 100,000–300,000 cycles.
- NAK80 steel: 500,000 cycles or more.
- H13 hardened steel: easily exceeds 800,000–1,000,000 cycles.
Good maintenance (such as regular cleaning, lubrication, and avoiding overloads) can extend lifespan by 20–50%, while poor practices cause significant reduction.