Natural fiber-reinforced composite materials are finding wide acceptability in various engineering applications. A substantial increase in the volume of production of these composites necessitates high-quality cost-effective manufacturing. Drilling of holes is an important machining operation required to ascertain the assembly operations of intricate composite products. In the present experimental investigation, natural fiber (sisal and Grewia optiva fiber)-reinforced polylactic acid-based green composite laminates were developed using hot compression through film stacking method. The drilling behavior of green composite laminates was evaluated in terms of drilling forces (thrust force and torque) and drilling-induced damage. The cutting speed, feed rate, and the drill geometry were taken as the input process parameters. It was concluded that all the three input process parameters affect the drilling behavior of green composite laminates. The drill geometry was established as an important input parameter that affects the drilling forces and subsequently the drilling-induced damage.

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The demand for polymer composites in structural and nonstructural applications has expanded rapidly due to their lightweight, high strength, and stiffness characteristics. Joining of polymer composite is not an easy task as inadequate joint strength leads to failure of a structure due to stress concentration. The following are the three basic methods available for joining of thermoplastic composites: adhesive joining, mechanical fastening, and fusion bonding. Electromagnetic joining is a class of fusion bonding where electromagnetic force is used for generation of heat. Electromagnetic joining has gained new interest among the research fraternity with the development of thermoplastic composites. This type of joining or welding technique offers many advantages over other joining techniques. This joining technique can be used for assembly as well as repairing of thermoplastic polymer‐based composites parts. The main aim of this article is to review the different electromagnetic joining methods for thermoplastic composites and present the recent developments in this area. The electromagnetic joining methods such as induction welding, microwave welding, and resistance welding have been comprehensively discussed in the context of their applicability for joining of thermoplastic polymer‐based composites. POLYM. ENG. SCI., 59:1965–1985, 2019. © 2019 Society of Plastics Engineers

This article presents micro electrical discharge machining (μEDM) of carbon fiber‐reinforced plastics (CFRP) with rotating tool electrode and assisting electrode (AE). The experimental investigation majorly focused on establishing the mechanisms of material removal and surface integrity of the machined blind holes. Taguchi and regression analysis were carried out to assess the material removal rate (MRR). Analysis of variance (ANOVA) was applied to understand the significance of input parameters and their contribution toward achieving maximum MRR. The surface integrity of the machined hole and damage modes of composite constituents were also examined through micrographic images. The experiments were carried out varying the voltage, pulse duration, and tool speed at three levels. The investigations showed that μEDM process can be applied for fabricating micro holes in CFRP if assisting electrode (AE) is used to initiate the spark. From the analysis of variance (ANOVA), it was observed that the percentage contribution of voltage, pulse duration, and tool rotational speed on MRR are 75.09, 5.20, and 16.09%, respectively. The optimal condition for the highest MRR was found to be V3/T1/S3 (voltage of 170 V, pulse duration of 10 μs, and tool speed of 800 rpm). The calculated value of MRR (341,264.94 μm3/s) at the optimum level of input parameters was found to be close to the experimental MRR (340,727 μm3/s). The percentage error between the experimental and calculated value of MRR at the optimum level is very low as 0.15%. This indicates that the developed statistical model is quite significant in predicting MRR during μEDM of CFRP. POLYM. COMPOS., 40:4033–4041, 2019. © 2019 Society of Plastics Engineers