Zinc alloy has been playing an important role in hot chamber die casting because of its good die casting and mechanical properties. Advantages of zinc alloys are low melting point, slow melting and heat preservation, less heating of chamber and die-casting wall. How to reduce defects and produce zinc alloy die castings that meet requirements are mainly affected by five factors.
Die-casting machine is the key equipment in die-casting production. Its performance objectively determines quality of die-casting. Correct selection of die-casting machine is very important to ensure product quality, improve production efficiency and reduce production cost. Performance of die-casting machine depends on two aspects.
Because zinc alloy must fill cavity in a short time, design and fabrication of die casting mould and its runner system is much more demanding than that of plastic die. Runner system guides metal solution to fill cavity in a certain way. It plays an important role in direction of flow, pressure transfer, filling time, exhaust condition and temperature distribution of metal solution. It is also an important factor to determine quality of die castings. Design principle of runner system of die casting mould should be aggregated from gooseneck pipe to gate, avoid sharp bending angle, smooth surface of flow path, so as to reduce resistance and maintain flow speed of liquid zinc alloy.
It is very important to control surface temperature of zinc alloy die casting mould to produce high quality zinc alloy die casting. Improper die temperature will lead to dimension instability of zinc alloy die castings. During production process, casting deformation will be ejected, resulting in defects such as hot pressure, viscous die, surface depression, shrinkage holes and hot bubbles. When mold temperature difference is large, variables in production cycle, such as filling, cooling and spraying time, will be affected to varying degrees. Therefore, zinc alloy die casting mould temperature machine is an important tool to improve quality of zinc alloy die casting. Die casting die temperature machine can improve product quality, production efficiency, reduce damage of high temperature metal alloy liquid to mould.
Main components and impurities in zinc alloy have a great influence on quality of die castings, which should be strictly controlled and mastered. Contents of Al, Cu, Mg and Fe should be appropriate, and no other impurities which may cause intergranular corrosion should be avoided. Therefore, reasonable control of alloy composition and prevention of impurity mixing are also key to zinc alloy die casting.
Even if there are zinc alloy die-casting machine with excellent performance, reasonable runner die, die-casting temperature machine with high precision of temperature control and best zinc alloy material, it is impossible to produce high-quality products with high efficiency if the management is not good and operation is improper. Therefore, operators need to be properly trained and familiar with performance and operation methods of various equipment.