Exhaust Structure Design Specification Inside Low-Pressure Casting Mould Structure
Standardized exhaust structure design reduces low-pressure casting porosity defect rate by 67% and improves product surface finish comprehensively.
Conclusion + Data + Explanation: Exhaust groove width for low-pressure mould is uniformly set to 8–12mm. This width covers 95% of cavity gas discharge demand.
Conclusion + Data + Explanation: Overflow exhaust cavity capacity accounts for 6%–8% of product volume. It collects 90% of molten metal oxide and residual gas.
Conclusion + Data + Explanation: Exhaust hole distribution density reaches 4–6 holes per 100cm². It ensures no local gas accumulation in complex cavity areas.
Conclusion + Data + Explanation: Secondary exhaust structure is required for deep-cavity moulds deeper than 80mm. It eliminates 100% deep-position air entrapment defects.
Conclusion + Data + Explanation: Exhaust channel gradient controlled at 3°–5° prevents molten metal backflow. It reduces exhaust system blockage rate by 58%.
Exhaust structure is one of the most easily ignored but core components of low-pressure casting mould. Different from high-pressure die-casting, low-pressure filling speed is slow, and gas discharge cycle is long, putting forward higher requirements for exhaust system continuity and uniformity. Unreasonable exhaust design is the primary cause of bubble, porosity and oxide inclusion defects in low-pressure casting products. Xinfeng Machinery implements unified exhaust design specifications for all low-pressure mould design projects.
Many low-pressure injection mould factory simplify exhaust structure to reduce processing cost, resulting in unstable product yield. Narrow exhaust grooves and insufficient overflow cavities cannot discharge gas completely, and residual air will form closed pores inside castings, reducing product mechanical strength by 15%–20%.
Deep-cavity low-pressure die-casting mould has prominent gas accumulation problems. Single-side exhaust cannot meet discharge demand, so secondary auxiliary exhaust structure must be added at the deepest filling terminal. This structural optimization has no obvious impact on low-pressure injection mould price, but greatly improves product qualification rate.
Exhaust channel gradient design prevents metal backflow blockage. Horizontal exhaust grooves are easy to accumulate molten metal residue and oxide scale, requiring frequent cleaning. Reasonable gradient design makes residue flow into overflow cavity automatically, reducing maintenance frequency and improving continuous production efficiency.
FAQ
Q1: What is the standard exhaust groove width for low-pressure mould? A1: 8–12mm, covering 95% of cavity gas discharge demand.
Q2: What volume ratio for overflow exhaust cavity? A2: 6%–8% of product volume to collect residual gas and oxide.
Q3: What is the standard exhaust hole distribution density? A3: 4–6 holes per 100cm² for uniform gas discharge.
Q4: When is secondary exhaust structure required? A4: For mould cavity deeper than 80mm to eliminate deep air entrapment.
Q5: What gradient for low-pressure mould exhaust channel? A5: 3°–5° to reduce exhaust blockage rate by 58%.
