Design and Analysis of Fixture for Welding an Exhaust Impeller

Abstract

Fixture has direct impact upon welding quality, productivity and cost. Fixture used in welding process for holding di erent part that has to weld, so the part can be properly weld; other purpose of xturing is to reduce the distortion that is generated during cooling of weld. By that way we can reduce the production loss and also manufacturing lead time for welding, positioning and holding parts. The main cause of distortion is residual stress. There are many way to control the residual stress like preheating, peening, post weld heat treatment, stress relief by natural ageing, vibra- tory stress relief or by maintaining proper welding parameters like voltage, current, wire feed speed, welding speed etc. But xturing is basic requirement for reducing residual stress. This is project focus on reducing residual stress by design proper xture for exhaust impeller and also make the impeller balanced. The aim of the project is to develop xtureless design of impeller that is used for the exhaust of dust particles in drum mix plant of road construction equipment ma- chinery. Drum mix plant is used for mixing of concrete and other row material utilized in road construction. Impeller is used for the exhaust of dust particles less than 150 micron, running at 1200rpm. Unbalance mass of impeller has been reduced from 100g to 44g by using implementing proper cutting and welding process. Welding cost calculation has been carried and it is found that welding cost of proposed design is less as compared to old design, this is because of lesser weld metal disposition. Power calculation has been carried out and total power required to rotate impeller at 1200rpm and having mass of 60kg is 41.21hp. Accuracy of laser cutting and plasma cutting has been checked using exper- iment, it is found that laser cutting is better than plasma cutting at 3mm length. Design and analysis of xture for welding an exhaust impeller has been carried out using di erent modeling and analysis tools. 2D Design of impeller has been pre- pared using Solid Works 2009 and Autocad 2009. 3D modeling has been prepared out using Solid Works 2009 and Pro-E wild re4. Analysis part has been carried out using ANSYS Workbench. Steady state thermal analysis of blade has been carried out using ANSYS workbench, it conclude that at particular time instant temperature distribution on blade is vary from 52 C to 1400 C. Steady state structural analysis has been carried out using ANSYS Workbench, it is found that maximum equivalent stresses on body is 6.2396Pa which is less than allowable stress that is 167MPa due to this it will not e ect the strength of material. CFD analysis has been carried out using ANSYS CFX, it has been found that improper streamline in impeller assembly is generated due to many reason like improper pressure, improper design of casing and improper design of impeller blade.