Rapid manufacturing of copper components using 3D printing and ultrasonic assisted pressureless sintering: Experimental investigations and process optimization

The present work deals with the comprehensive study of ultrasonic and sintering parameters effect on the rapid manufacturing of pure copper components by ultrasonic assisted pressureless sintering and 3D printing. The customized sintering setup with the stepped horn was designed and fabricated for the experiments. First, the ultrasonic assisted sintering process was compared to conventional pressureless sintering process in regards of physical and mechanical properties of fabricated samples. The study revealed that the ultrasonic vibrations increased the contact area between the particles and raised the local heating for large sintering necks. Thus, the ultrasonic assistance enhanced the properties of the fabricated parts. Further, response surface methodology was used to design the set of experiments with sintering temperature, heating rate, soaking time and ultrasonic power percentage intensity to study the parameters effect. The analysis of variance was performed to analyze the significant contribution of parameters on relative density, compressive yield strength, and volumetric shrinkage. The sintering temperature and ultrasonic power percentage intensity dominated the other parameters with respect to responses. The less effect of low ultrasonic power intensity and short soaking time at high sintering temperatures was revealed by the significant interactions. Furthermore, the genetic algorithm based multi-objective optimization was used for the parameters optimization on maximizing relative density, compressive yield strength and minimizing the volumetric shrinkage. The efficacy of the developed method was tested by the fabrication of a customized heat sink on the optimized parameters.