Optimization of wear loss in silicon nitride (Si3N4)–hexagonal boron nitride (hBN) composite using DoE–Taguchi method

Introduction The contacting surfaces subjected to progressive loss of material known as ‘wear,’ which is unavoidable between contacting surfaces. Similar kind of phenomenon observed in the human body in various joints where sliding/rolling contact takes place in contacting parts, leading to loss of material. This is a serious issue related to replaced joint or artificial joint. Case description Out of the various material combinations proposed for artificial joint or joint replacement Si3N4 against Al2O3 is one of in ceramic on ceramic category. Minimizing the wear loss of Si3N4 is a prime requirement to avoid aseptic loosening of artificial joint and extending life of joint. Discussion and evaluation In this paper, an attempt has been made to investigate the wear loss behavior of Si3N4–hBN composite and evaluate the effect of hBN addition in Si3N4 to minimize the wear loss. DoE–Taguchi technique is used to plan and analyze experiments. Conclusion Analysis of experimental results proposes 15 N load and 8 % of hBN addition in Si3N4 is optimum to minimize wear loss against alumina

Optimization of drilling parameters for aluminum metal matrix composite using entropy-weighted TOPSIS under MQL conditions

The aim of the present work is to understand the effect of drilling parameters (drill speed and feed rate) during the drilling of a Saffil fiber-reinforced Al metal matrix composite (MMC) under minimum quantity lubrication (MQL) condition. The effect of drilling parameters on individual response characteristics is evaluated and the optimum drilling parameters are also investigated using a multi-response optimization technique known as the entropy-weighted technique for order performance by similarity to ideal solution (EWTOPSIS). The drilling parameter optimization is performed with the aim of minimizing surface roughness in the drilled hole, roundness error in the drilled hole and feed force during drilling. The drilling parameters have a significant effect on individual responses. Weights were assigned to each response using the entropy weight method, and closeness coefficients were calculated to obtain the optimal level for the drilling parameters. A drill speed of 11 m/min and a feed rate of 0.05 mm/rev are the optimal combination to minimize the desired output responses simultaneously

Biomaterials in hip joint replacement

Total hip joint replacement is unavoidable in the orthopedic application, for improving the quality of patient life suffering from arthritis. Replacing damaged joint with artificial joint gaining popularity and it became a need in such cases. While joint replacement represents success stories in the field of orthopedic surgery, but maintaining implant for last long is still challenge. The average lifespan of hip joint replacement is about 15 years. Last 50 years research in the field of orthopedics trying to evaluate the biomaterials for hip joint replacement with improved performance in terms of extending joint life. In early days different kind of natural materials like wood, glue, rubber, tissue from living forms and manufactured materials like iron, gold and zinc were used as biomaterials based on trial and error. Biomaterials are such materials which are intended to replace a part or function of the body in reliably economically and physiologically acceptable manner. The aim of this review is to present the overall evaluation of biomaterials mainly developed for a hip joint replacement from early days to current days. In this paper attempt has been made to summarize the evolution of the biomaterial from early days of metals, polymers to present days of ceramics commonly used in the field of orthopedic for hip joint replacement