Spot welding

About: Spot welding is a research topic. Over the lifetime, 12491 publications have been published within this topic receiving 89845 citations. The topic is also known as: Spot_welding.

Resistance spot welding

Abstract: PURPOSE:To estimate a nugget diameter in real time without making the destruction inspection of a weld zone by correcting the temp. distribution of base metals calculated at the point of this time in accordance with the average temp. of the base metals recognized from the moving quantity of electrodes detected after the start of welding. CONSTITUTION:The temp. distribution of the base metals 6 is calculated in a signal processing section 15 in accordance with the two detected values detected by a welding current detecting section 3 and an inter-tip voltage detecting cable 14. The characteristic value of the nugget size is estimated therefrom in an estimation section 16. Resistance spot welding is executed by controlling the welding current and electrode pressurizing force therefrom. The moving quantity of the electrodes 7 after the start of welding is detected by a detector 14 and the temp. distribution of the base metals 6 calculated at the point of this time is corrected in accordance with the average temp. of the base metals recognized in the signal processing section 15 from the moving quantity. Correct welding conditions are automatically selected in this way and the desired weld zone is assured.

Progressive ultrasonic welding system

Abstract: A method of progressively ultrasonically welding together workpieces is provided wherein the spot welds effected are initiated as small points and then progressively grow to full size. The method employs an ultrasonic welding apparatus of the type having a welding tip and a complimentary anvil between which the workpieces to be welded may be inserted. The workpieces are first clamped together and the workpieces "presqueezed" to disperse any adhesives which may be used between the workpieces. Initial pressure and energy levels are then introduced to "scrub" the workpieces. Pressure and energy are then synchronously ramped in phase to maximum levels to effect a weld between the workpieces. The welding operation is controlled by control means which permit automatic synchronization of the operation.

Parametric study of FSSW of aluminium alloy 5754 using a pinless tool

Abstract: A parametric study of friction stir spot welding (FSSW) of lap joints in aluminium alloy 5754 using a pinless tool with scrolled shoulder is presented. Experimental plan was done according to the response surface methodology (RSM), where tool rotation speed varied between 988 and 3511 rev/min, plunge rate between 24.4 and 150 mm/min and dwell time between 1 and 3.5 s. The plunge depth was held constant at 0.4 mm. During welding, the axial force and torque were monitored using a dynamometer. The welds were tensile shear tested, and the broken samples were visually examined. The weld bond line and microstructure were analysed using light optic microscope under polarised light, and SEM was used for examination of fractured surface. Mathematical models describing the relationship between welding parameters and joint strength, axial force and torque were developed. FSSW parameters, at which maximal joint strength was obtained, were considered as optimal. At these welding parameters, the axial force and torque were in the lower range among tested parameters. Material flow and joint formation are experimentally presented and schematically illustrated.