The growing use of carbon-fibre-reinforced polymer (CFRP) composites as high-performance lightweight materials in aerospace and automotive industries demands efficient and low-cost machining technologies. The use of laser machining for cutting and drilling composites is attractive owing to its high speed, flexibility, and ease of automation. However, the anisotropic material properties of composites, and issues related to the heat-affected zone (HAZ), charring, and potential delamination during laser processing, are major obstacles in its industrial applications. In order to improve the quality and dimensional accuracy of CFRP laser machining, it is important to understand the mechanism of the transient thermal behaviour and its effect on material removal. Based on the ‘element death’ technique of the finite element (FE) method, a three-dimensional model for simulating the transient temperature field and subsequent material removal has been developed, for the first time, on a heterogeneous fibre—matrix mesh. In addition to the transient temperature field, the model also predicts the dimensions of the HAZ during the laser machining process. Experimental results obtained with same process variables using a 355 nm DPSS Nd:YVO4 laser were used to validate the model. Based on the investigation, the mechanism of material removal in laser composite machining is proposed. The results suggest that the employed FE approach can be used to simulate pulsed laser cutting of fibre-reinforced polymer composites.

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Submerged arc welding (SAW) is one of the chief metal fabrication processes in industry. It works with high current density and can affect high metal deposition rate. The present work emphasizes the influence of process parameters on quality and performance of submerged arc weldment by incorporating one of the traditional methods of statistical data analysis i.e. ANOVA. This approach aims to reveal the main and interactive effects of process parameters on different response variables associated with the weldment. Based on factorial design without replication, experiments were conducted with three different levels of process parameters like voltage, welding current and electrode stick out to obtain butt joints from mild steel plates. Experimental results were examined by exploring Analysis of Variance Method, using statistical software package MINITAB. liased on ANOVA, several graphical plots are shown-histogram of residuals, normal plot of residuals, residual verses order and residual verses specified variables etc. ANOVA delivers feasible data to justify the significance of process parameters on different response variables of submerged arc weldment in terms of their main effects and interactive effects. The effects due to variation of process parameters on (i) bead geometry in terms of bead width, depth of penetration, reinforcement, and (ii) bead quality as well as performance of the welded joint in terms of hardness, impact value and tensile strength are represented graphically. Graphical representations of the experimental data are supposed to contribute 149 Brought to you by | Western University Authenticated Download Date | 6/9/15 10:39 AM Vol. 17, No. 3, 2006 Effect of Process Parameters on Submerged Arc Weldment valuable information for quality control of submerged arc welding process, which would help to obtain superior quality weld and also to achieve high productivity.

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