​​​Ahmed Kangda

The project undertaken involved thorough understanding of processes used in foundries, expectations of shop floor and finding solutions to real-time industrial challenges. Beginning with understanding of processes, ample time was devoted to building concepts on aluminum casting. Practical knowledge was inculcated by urging to step out of the theoretical dome of concepts.

Once strengthening of concepts was achieved, assembly line visits were undertaken. Through the scrolls at shop floor and interaction with operators many minute details were gathered about the process flow at TATA Motors. The study was confined to two problematic components on the line; namely, Front Half (MODEL X) and Rear Cover (MODEL Y) of gearbox casing. Visual inspection and other quality checks were conducted to ascertain the causes of rejection. Analysis of rejection trends at shop floor were also studied. The study was not just limited to the shop floor of TML but it was extended to the shop floor of casting foundries like M/s Endurance Technologies. Ample time was devoted to the shop floor of foundry. Complete process understanding was achieved over here and all doubts and queries were clarified by experts of foundry. Following this, brainstorming sessions were conducted wherein, causes of rejections were discussed. Grading was carried out on the basis of functionality and blowhole susceptibility. Effect of various process parameters on the casting practice were the major agendas of the sessions. Susceptible areas of leakage were identified for the two components. These have been forwarded to the design engineer with the objective of shifting the blowholes to the non-functional areas by redefining the casting practice. However, shifting blowholes to the non-functional area does not eliminate the blowholes and other casting defects.

Going a step further, perseverant efforts were put in to minimize the casting defects. Six Sigma tools of process optimization were used to enhance the current process of casting manufacture. Taguchi method, an efficient problem solving tool to upgrade the performance of products and processes with a significant reduction in cost and time involved, has been used. Analysis of research papers on Casting defect minimization by Taguchi method has also been done as a part of this project. The casting process of supplier, M/s Endurance Technologies was studied and important process parameters have been identified.

On the basis of data provided, a proposed template of experimentation has been forwarded to the Engineering Research Centre (ERC). For a department working in tandem with the supplier such kind of experimentation is not recommended. This is so because, for certain set of trial the defect percent may be very high. In such a case rejection may lead to significant monetary losses. Apart from the monetary loss, the unavailability of component at the time of assembly would lead to loss of productivity. An efficient and economical method of reducing casting rejection has also been proposed. This method is less time consuming and delivers satisfactory results in an already established process of casting manufacture. Thus this method can be applied to the current scenario of minimizing rejection of GB 27 Rear cover and G550 Front half due to blowholes. The aim of achieving a robust design can be achieved in this way.