Machining operation optimization improves the quality of the product, reduces cost, enhances overall efficiency by reducing human error, and enables consistent and efficient operation. It is a vital decision-making process and achieves the best solution within constraints. It reduces reliance on machine-tool technicians and handbooks to identify cutting parameters, as a lack of awareness of the optimal combination of machining parameters leads to several machining inefficiencies. Subsequently, the optimization of the machining process is more useful for units of production, particularly machining units. In multi-objective optimization (MOO) problems, weights of importance are assigned, mostly identical. But, nowadays, the weights assignment techniques have received a lot of consideration from the professionals and researchers in MOO problems. Various techniques are developed to assign weights of significance to responses in MOO. The Entropy weights method (EWM) continues to work pleasingly across diverse machining operations to allocate objective weights. In this paper, a literature review is conducted to classify the articles on EWM applications in machining operations. The categorization proposal for the EWM reviews included 65 academic articles from different journals, books, and conferences since the year 2009. The EWM applications were separated into 18 categories of conventional and non-conventional machining operations. The implementation procedure of EWM is presented with an example along with method development. Scholarly articles in the EWM applications are further inferred based on (1) implementation of EWM in different machining operations, (2) MOO methods used with entropy weights in machining operations, (3) application of entropy weights by citation index and publication year, and (4) entropy weights applications in other fields. The review paper provided constructive insight into the EWM applications and ended with suggestions for further research in machining and different areas.

Revealing the benefits of entropy weights method for multi-objective optimization in machining operations: A critical review

Burr is one of the main macro-geometrical types of damage concerning machined features of carbon fibre reinforced polymer (CFRP) composites. Even if it does usually not weaken the strength of composite materials, it is recommended to be removed. The deburring process often leads to significantly increased operation time and cost. In both the industry and academia, digital processing of optically captured images is the most common evaluation method for burr-characterisation. Nevertheless, there is no agreement on the measures and techniques of burr-evaluation in CFRPs. Recent key papers on burr formation, measurement and evaluation in CFRPs are reviewed in an attempt to standardise and classify burr characterisation related expertise. In this paper, burr formation mechanisms, burr measurement methods and burr parameters are critically reviewed, compared and discussed. The main advantages and disadvantages of burr measures are highlighted and their possible future applications and prospects are also considered. Furthermore, burr measures reviewed are compared and discussed based on an experimental data set.

A critical review of the drilling of CFRP composites: Burr formation, characterisation and challenges

There is more demand for natural fiber-reinforced composites in the energy sector, and their impact on the environment is almost zero. Natural fiber has plenty of advantages, such as easy recycling and degrading property, low density, and low price. Natural fiber’s thermal properties and flexural properties are less than conventional fiber. This work deals with the changes in the thermal properties and mechanical properties of S-glass reinforced with a sodium hydroxide-treated pineapple leaf (PALF) and banana stem fibers. Banana stem and pineapple leaf fibers (PALF) were used at various volume fractions, i.e., 30%, 40%, and 50%, and various fiber lengths of 20 cm, 30 cm, and 40 cm with S-glass, and their effects on the thermal and mechanical properties were studied, and their optimum values were found. It was evidenced that increasing the fiber volume and fiber length enhanced the flexural and thermal properties up to 40% of the fiber volume, and started to decrease at 50% of the fiber volume. The fiber length provides an affirmative effect on the flexural properties and a pessimistic effect on the thermal properties. The PALF S-glass combination of 40% fiber load and 40 cm fiber length provides maximum flexural strength, flexural modulus, storage modulus, and lowest loss modulus based on hybrid Taguchi grey relational optimization techniques. PALF S-glass hybrid composite has been found to have 7.80%, 3.44%, 1.17% higher flexural strength, flexural modulus, and loss modulus, respectively, and 15.74% lower storage modulus compared to banana S-glass hybrid composite.

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Influence of Fiber Volume and Fiber Length on Thermal and Flexural Properties of a Hybrid Natural Polymer Composite Prepared with Banana Stem, Pineapple Leaf, and S-Glass

To optimize the machining process, finding the minimum uncut chip thickness is of paramount importance in micro-scale machining. However, strong dependency of the minimum uncut chip thickness to the tool geometry, workpiece material, tool-work friction, and process condition makes its evaluation complicated. The paper focuses on determination of the minimum uncut chip thickness experimentally during micro-end milling of titanium alloy Ti-6Al-4V with respect to influences of cutting parameters and lubricating systems. Experiments were carried out on a CNC machining center Kern Evo with two flute end mills of 0.8 and 2 mm diameters being used in the tests for micro- and macro-milling, respectively. It was found that the micro-milling caused more size effect than macro-milling due to higher surface micro-hardness and specific cutting forces. The specific cutting force depended strongly on feed rate (f
 z) and lubricating system, followed by depth of cut (a
 p) and cutting speed (v
 c), mainly in the micro-scale. All output parameters were inversely proportional to the specific cutting force. Finally, depending on different process parameters during micro-milling of Ti-6Al-4V, the minimum uncut chip thickness was found to vary between 0.15 and 0.49 of the tool edge radius.

Determination of minimum uncut chip thickness under various machining conditions during micro-milling of Ti-6Al-4V

A critical review addressing the drilling-induced damage issues for CFRP composites

Experimental investigation of vegetable oil as dielectric fluid in Electric discharge machining of Ti-6Al-4V

Selection of optimum machining parameters in machining operations leads to good functional attributes for the machined components and increased productivity. In this work, machining parameters and ...

Multi-objective optimization of turning parameters using the combined moora and entropy method

Application of MCDM Method for the Selection of Optimum Process Parameters in Turning Process

Performance analysis of micro textured cutting insert design parameters on machining of Al-MMC in turning process

Multi-objective optimization method is used to simultaneously maximize and minimize the various criteria involved in complex industrial problems. In the present work, the optimum combination of cutting parameters is estimated in the turning of EN25 steel with coated carbide tools by performing desirability function analysis and utility concept. The experiments were designed as per L18 Taguchi mixed level orthogonal array with each trial performed under different conditions. These methods are employed for minimization of cutting force, surface roughness and maximization of material removal rate. The optimized results are compared and utility concept gave good combination of input and output parameters. Finally, Analysis of Variance (ANOVA) on overall desirability and utility value was employed to identify the relative significance of factors in terms of their percentage contribution to the responses.

B. Singaravel

Papers

Experimental investigation of vegetable oil as dielectric fluid in Electric discharge machining of Ti-6Al-4V

Multi-objective optimization of turning parameters using the combined moora and entropy method

Application of MCDM Method for the Selection of Optimum Process Parameters in Turning Process

Performance analysis of micro textured cutting insert design parameters on machining of Al-MMC in turning process

Application of Desirability Function Analysis and Utility Concept for Selection of Optimum Cutting Parameters in Turning Operation