Judgment Criteria for Scrapping Instead of Repairing Aluminum Alloy Molds

Aluminum alloy casting molds have fixed service life and fault judgment standards in industrial production, and scientific scrapping judgment can avoid ineffective repair cost waste and unqualified product output. Many enterprises blindly repair aging molds, resulting in increased production cost and unstable casting quality. According to aluminum mold industry maintenance specifications, multiple core indicators can be used as scrapping judgment bases. First, crack defect indicator: when the mold cavity crack depth exceeds 0.5mm, the crack has penetrated the surface hardened layer and destroyed the internal stress balance of the mold body, and conventional welding repair cannot restore mold precision and structural stability, so it must be scrapped. Second, precision loss indicator: permanent dimensional precision loss exceeding 0.03mm has exceeded the debugging adjustment range of casting process, unable to meet product tolerance standards. Third, repair frequency indicator: molds with more than 5 repair times per 1000 production batches have severe structural fatigue, and subsequent repair effect is poor with high fault recurrence rate. Fourth, surface damage indicator: large-area thermal peeling with area exceeding 8% of the mold cavity cannot be repaired by polishing and nitriding. In addition, molds reaching the design upper limit of production batches (15000 batches for low-pressure molds, 8000 batches for gravity molds) must be scrapped uniformly to eliminate production safety risks.