Q: What main defects do die casting molds tend to have?
A: Thermal cracking, material sticking, erosion, deformation, slag clogging, flash, cavity scratching, uneven cooling.
Q: What is the normal lifespan of a die casting mold in shots?
A: General zinc / aluminum alloy molds last 80,000–150,000 shots; precision molds can reach 200,000–300,000 shots.
Q: Why do die-cast parts produce flash and burrs?
A: Excessive mold clamping gap, insufficient locking force, mold deformation and parting surface wear.
Q: What causes parts to stick to the mold?
A: Uneven release agent spraying, overhigh mold temperature, rough cavity surface and excessive alloy fluidity.
Q: How does thermal cracking occur on die casting molds?
A: Large stress from repeated heating and cooling, improper heat treatment of mold steel and insufficient preheating.
Q: How to extend the service life of die casting molds?
A: Adopt premium hot work mold steel, standard heat treatment, proper preheating, regular maintenance and standardized release agent spraying.
Q: What surface treatments are required for die casting molds?
A: Nitriding, carburizing, polishing, hard chrome plating and PVD coating to improve wear resistance and anti-sticking performance.
Q: What are the consequences of poor mold cooling system design?
A: Part shrinkage, porosity, deformation, longer cycle time and easy mold cracking.
Q: What problems are caused by poor venting of die casting molds?
A: Part porosity, burnt marks, incomplete filling and reduced mechanical strength.
Q: Can mold steel be shared for zinc alloy and aluminum alloy die casting?
A: Not recommended. Aluminum alloy brings stronger corrosion and erosion, requiring higher-grade hot work steel.
Q: Why does the die casting mold scratch the part surface?
A: Cavity burrs, insufficient polishing, tight ejector pin fit and adhered metal carbon deposits.
Q: What does daily maintenance of die casting molds include?
A: Clean parting surfaces, check vent grooves, polish slight scratches, inspect ejector pins and perform rust-proof storage.
Q: What is the optimal mold preheating temperature?
A: Zinc alloy: 180–220℃; Aluminum alloy: 200–260℃.
Q: What are the impacts of unrigorous runner and gate design?
A: Poor filling, severe air entrapment, uneven part wall thickness and higher rejection rate.
Q: Which parts are mainly repaired on die casting molds?
A: Parting surfaces, vent grooves, cracked & scratched cavities, ejector pin holes, eroded gates and runners.
