Investigation of Friction Stir Butt Welded Aluminium Alloy Flat Plates Using Spindle Motor Current Monitoring Method

Friction-stir welding (FSW) is a solid-state joining process and used to join light alloy metals, which finds various industrial applications in aerospace, automotive and ship building, etc. Monitoring and control of friction-stir welding is essential for ensuring defect free and high strength welded joints. This paper presents spindle motor current monitoring approach for analyzing the weld tensile strength of friction stir welded components. Aluminium alloy of 6063-T6 plates with 4 mm and 6 mm thicknesses were joined by friction stir welding process using square, circular, triangular and conical tool pin profiles. The spindle motor current was measured by using a Hall Effect non-contact current sensor, which was interfaced with a data acquisition system. Measured current signals are useful to identify the different stages of friction stir welding process. Experimental results show a fairly linear trend between the tensile strength of welded joints and the percentage change in spindle motor current. Proposed method provides a simple approach for online monitoring of weld strength in friction stir welding process.