Research Projects

Laser based material deposition technique such as laser based directed energy deposition (LDED) can refurbish costly worn out parts. However, expensive and foreign laser source poses difficulty in its purchase and cost-effective timely maintenance by the small and medium-sized enterprises in India. This along with the lack of awareness regarding the capability of LDED has forced them to follow the traditional linear “take-make-use-dispose” model. Not refurbishing costly worn out parts, not only causes economic loss but also damages the environment, erecting steep barrier to attain one of the sustainable development goals (SDGs) i.e. Sustainable Manufacturing. Therefore, the current proposal aims to address the technological challenges in the way of cost-effective retro-fitting of an industrial welding robot with arrangements for laser based deposition for repairing of components. Such a system with in-house developed laser is currently not present in India, as per the knowledge of the authors of this proposal. Continuous wave Yb fibre laser (wavelength 1070 nm) with a minimum 350 W power and good beam quality (M2 less than 5) has been developed at CSIR-CGCRI. A low weight ( around 4 kg) laser cladding head shall be developed at CSIR-CMERI that should have provision for at least beam focusing lens for the laser just mentioned, protective glass window, inert gas shielding of window, metal powder mixing and suitable nozzle to deliver the powder jet at the focal spot of the laser beam. Copper and brass are the material considered for the nozzle and rest of the cladding head. Push fit arrangement shall be kept for inserting flexible polymer pipes carrying gas (high purity Argon) and powder stream. The nozzle shall be designed with the help of powder flow analysis using ANSYS software. A gravity-based or fluidized-bed powder feeder unit with two hoppers shall be procured and integrated with the developed laser cladding head. These three components shall be retrofitted to a 6-axes IRB 1410 industrial welding robot (Make: ABB) with 5 kg payload capacity, available and operational at CSIR-CMERI. Design of experiments of single layer and multi-layer laser cladding of AISI 316L powder shall be carried out to assess the process capability. Finally, capability of the developed set up shall be demonstrated in refurbishing a few worn out industrial parts. The worn volume shall be scanned with a 3D scanner generating its CAD model in STL format. This shall help in slicing and tool path generation using open source software like Slice3R. However, those software usually deal with material extrusion based additive manufacturing process. Hence, some commands related to heating and flow of filaments have to be replaced with corresponding commands related to laser on/off and powder flow on/off. Laser power and powder flow rate shall be controlled separately from the respective sources. Deposited layer shall be remelted to reduce surface roughness and other defects.