Study On Cleaning Equipment And Method Of The Sand Cores For Magnesium Alloy Castings

With the rapid development of the automotive, aviation and aerospace industry, the demand of complex thin-walled magnesium alloy castings is continuously increasing. But, cores for forming these castings are very complex, and the casting temperature of magnesium alloy is very low, so it lead to clean-up difficulties of sand cores. Therefore, the research and development of magnesium alloy casting sand core cleaning equipment and methods have important theoretical significance and practical value.A new sand cores cleaning equipment was designed in this paper. The device which integrates chemical dissolution, vibration crushing and ultrasonic cleaning can be used for efficient cleaning of magnesium alloy casting sand core. The main purpose of chemical dissolution is to dissolve and soften core. The vibration is using inertial force to broken and remove core. The ultrasound cleaning can accelerate the clean-up of the sand core by ultrasonic cavitation.The effects of different process parameters on the cleaning efficiency of cores were tested by using the developed core cleaning device. The results show that cleaning efficiency increases with the growth of concentration of NaOH solution and heating temperature, increases first and then decrease along with the increasing of excitation force when using dissolution-vibration cleaning method. The results show that cleaning efficiency increases with the growth of ultrasonic power, concentration of NaOH solution and heating temperature when using dissolution-ultrasonic cleaning method.The optimized process of core cleaning was confirmed by orthogonal experiment. The optimized process parameters of SQG resin-sand core are as follows: 5% concentration of NaOH cleaning solution, 2/18? eccentric block angle of vibration motor, 600 W ultrasonic power. The optimized process parameters of pre-coated sand core are as follows: 5% concentration of NaOH cleaning solution, 2/18? eccentric block angle of vibration motor, 600 W ultrasonic power.The change of heating temperature of core during casting of complicated magnesium alloy component was simulated in this paper. The results show that the heating temperature of core is low during casting, and the time of the heating temperature over 250? is short, about 23 minutes. The sand core is difficult to be collapsed by low temperature heating, and it lead to clean-up difficulties of sand cores.The actual casting and cleaning of magnesium alloy component were investigated by using the optimized process parameters. The complexity of the Resin-sand core which has good permeability determines the efficiency of cleanup. To the pre-coated sand core which has bad permeability, the size of the sand core has a significant impact on the degree of difficulty of removal of sand core.