Die-casting Technology And Its Optimization Of The Small And Medium-sized Motor Rotors

Motor rotor is the driving component for mechanical system, and its skeleton is produced by stacking silicon steel plates. Tilted slots are enclosed by stacked plates. The shape complexity renders the foundry process challenging. This work attempts to improve the rotor performance. It generally focuses on die casting of small and medium size aluminum rotor. Influences of casting process shading on the final product were extensively studied, upon which the optimized parameters were proposed.Based on DMPC aluminum rotor of frame No.160M2-2, it designs the die casting technology and the optimization. 5 parameters were tested and discussed in detail: metal liquid temperature, mould temperature, injection high speed, injection low speed, pressure of supercharging and holding. Except for that, additional parameters were studied in general, that include preheat temperature of iron core, switch position of high/low speed, duration time of supercharging and holding. The cast defects led by varied parameters were analyzed. Experimental results support the following findings :(1) The defect of misrun could be apparently inhibited by increased metal liquid temperature,but too high, the cast will be undermined by gas hole and casting fins;(2)Elevated mould temperature helps to improve metal fluidity and avoid cold shut, but the temperature is too high, forming shrinkage defect.;(3)If the injection low speed takes a lower value, the aluminum melts tend not to entrap air, but the super cooling melts engages unwanted cold shut. On the other hand, in case of elevated speed, the fluidity is enhanced in cost of air entrapment and blowhole;(4)Raising the injection high speed guarantees the work pieces integrity, especially its back end-ring. Unfortunately, this should not be too progressive because it will lead to joint flash;(5) Blow hole will be dispersed by high supercharging pressure, however, if too high, it will produce joint flash and sticking the mould.This work was carried out for 160M2-2 aluminum rotor. Case study has clarified impacts of casting parameters on the final product, through which optimized values were obtained. Experiments and optimization have yielded qualified cast and operation parameters: pouring metal liquid temperature at 700?,average injection low speed of 0.8m/s, high speed 3m/s, supercharging pressure takes 50 MPa,mould preheated to 300? and iron core 300?,high/low speed switched at 285 mm away from the end of apparatus chamber, pressure be hold for 4 seconds.It can be seen through experimental result that broken bar led by manufacturing was completely avoided. In addition, porosity ratio at the rotor end was decreased from 10% to 2%, and the tested productivity has increased by 0.9%. Benefited from this work, the qualified products ratio gets improved from 93% to 98%, which brings tangible benefits to enterprises.