Papers by Author: Shu Qin Shi

Abstract: The simulation of temperature field during laser direct metal deposition(DMD) were researched. The finite element model of single track cladding, multi-track overlapping and multi-layer deposition were established. The temperature field was simulated by ANSYS software basing on life-and-death element and cycle algorithm. Under different process parameters, the temperature and temperature gradient on the cross-section of sample were simulated during single- track scanning, multi-track overlapping and multi-layer deposition. Temperature cycle curves at different position were analyzed and were consistent with actually value. Both simulation and experiment showed that heat accumulation during continuous forming greatly affected the temperature of molten pool.

Abstract: Coaxial powder feeding with carrier gas is the key part of laser direct metal deposition (DMD) rapid prototyping system. The convergence of powder flow would greatly affect forming efficiency, precision and performance. Numerical calculation model of flow field was built and simulated in this paper. The results of simulation and analysis had shown that powder flow field was very complex. The flow process could be divided into two parts, converging process and dispersing process. The main influencing factors of convergence included powder feeding rate, carrier gas flow rate, and the distance from nozzle to molten pool. There was a convergent focus where utilization ratio of powder was maximum. So the distance from nozzle to molten pool must be adjusted to equal to convergent focus (1.5cm) during DMD.