P.M. Gopal

Dry sliding wear characterization of Al 6061/rock dust composite

Abstract The influence of rock dust size (10–30 µm) and mass fraction (5%–15%) on density, hardness and dry sliding wear behavior of Al 6061/rock dust composite processed through stir casting was investigated. Wear behavior of the developed composite was characterized at different loads, sliding velocities and distances using pin-on-disc setup. The experiments were conducted based on Taguchis L27 orthogonal array and the influence of process parameters on wear rate was studied using ANOVA. The experimental results reveal that the applied load and reinforcement size are the major parameters influencing the specific wear rate for all samples, followed by mass fraction of reinforcement, sliding velocity and sliding distance at the level of 47.61%, 28.57%, 19.04%, 9.52% and 4.76%, respectively. The developed regression equation was tested for its accuracy and made evident that it can be used for predicting the wear rate with minimal error. With the help of SEM images, the worn surfaces of the novel composite were studied and the analysis proves that the wear resistance of aluminium alloys can be well improved with the addition of rock dust as reinforcement.

WEDM of Mg/CRT/BN composites: Effect of materials and machining parameters

ABSTRACT The current work presents a detailed exploration on real-time wire electric discharge machining (WEDM) experiments and grey relational analysis (GRA)–based multi-criteria optimization of material and machining characteristics for lowered surface roughness (Ra) and improvised material removal rate (MRR) of the newly developed magnesium/boron nitride/cathode ray tube (Mg/BN/CRT) hybrid metal matrix composites (MMCs). The composites were fabricated through powder metallurgy (PM) route by reinforcing silica-rich E-waste CRT panel glass powder crushed for different particle sizes (10, 30, and 50 µm) at various weight percentages (5%, 10%, and 15%) and with 2% boron nitride (BN). Taguchi-based orthogonal array procedure was utilized to formulate the experimental plan for WEDM considering reinforcement level and size, pulse on time (Pon), pulse off time (Poff), and wire feed (Wf) as the input process parameters. ANOVA results reveal that Pon and wt% of reinforcement has more effect on Ra and MRR than any other considered parameters. The developed mathematical model for Ra and MRR predicted values similar to that of experimental results. Multi-criteria optimization was done through GRA technique and the so recommended optimum parameter set furnishes higher MRR (22.34 mm3/min) and reduced Ra (2.87 µm).

Wire Electric Discharge Machining of Silica Rich E-waste CRT and BN Reinforced Hybrid Magnesium MMC

The current work presents an experimental investigation and multi objective optimization of material and WEDM machining features for better surface finish (Ra) and material removal rate (MRR) for a newly made-up Mg/BN/CRT Hybrid MMC. Powder metallurgy route is followed for composite fabrication by reinforcing silica rich E-waste CRT panel glass powder of different particle sizes (10, 30 & 50 μm) at different weight percentages (5, 10 & 15%) and a fixed quantity of 2% Boron Nitride. Reinforcement weight percentage and size, pulse ON time, pulse OFF time and wire feed are considered as process parameters to design the WEDM experiments through Taguchi based orthogonal array technique. Based on the ANOVA results it is revealed that pulse ON time and reinforcement wt. % has higher influence over Ra and MRR when compared to any other parameters considered. The predicting ability of the developed mathematical models for MRR and Ra is found superior and it predicts similar values as that of experimental results. Multi objective optimization carried over through TOPSIS selects the optimal parameter for multi response and the TOPSIS recommended optimum parameter set delivers higher MRR (22.34 mm3/min) and reduced Ra (2.87 μm).

Parameteric Optimization of Surface Roughness in End Milling of Aluminium Rock Dust Composite

Recent developments in the composite materials with high performance increase its range of application most widely but the major disadvantage of these novel materials is machining. The selection of proper process parameters plays an important role in distinguishing machining quality. This work mainly concentrates on the selection of process parameter for minimizing the surface roughness in end milling operation for the newly developed aluminium rock dust metal matrix composite. Taguchi method is used to design and accordingly L27 orthogonal array with five factors viz particle size, weight percentage, cutting speed, feed and depth of cut each at three levels is employed. The experiments were performed in a CNC vertical machining center and corresponding surface roughness values are measured. From the collected data, ANOVA is performed and observations reveal that feed rate influence more on surface roughness followed by particle size, depth of cut, weight percentage and cutting speed.