Modification Integration and Testing of Multi Powder Hopper With Co Axial Nozzle for Laser Cladding

Abstract

The applications of Laser Metal Deposition (LMD) in favor of mankind are vast and the benefits of LMD as compared to conventional cladding processes necessities high level of research in low equipment cost especially for under develop countries like Pakistan. LMD process not only gives lower heat affect zone (HAZ) problems but also less dilution and porosity issues compared to other type of cladding processes. Due to Functionally Graded Materials (FGMs), this additive manufacturing technique is getting popular in biomedical, defense, automotive and aerospace industries. Multiple metal powders are allowed to pass via a nozzle and incoming powder-metal is simultaneously melted through a powerful laser beam thus forming a melt pool. After solidification a metal clad of different grade is formed and process is repeated for other layers. Thus, by changing the metal powder proportion the clad properties can be changed resulting into better functional properties of the part. 2. The main equipment of LMD consists of powder feeding mechanism, optical Laser system and a nozzle. The powder feeding mechanism is important for FGM and consist of multiple solutions, one of them is control of feeder discs with stepper motor controls, which is successfully considered in this research. The aim of this research is to re-design a multi powder hopper machine and a co-axial nozzle. Moreover, integration of in-house design co-axial clad nozzle with powder feeding system is a challenging task. This is followed by testing of complete system to quantify the efficiency of both nozzle and multi-powder hopper machine with respect to powder mass flow rate and concentration of powder stream at the nozzle exit. As the whole setup is an initial prototype and limits the use of laser at this stage therefore other parameters affecting the Laser cladding process cannot be validated. However, LMD is a vast technique in additive manufacturing and is expected to grow under advance research activities.