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Electron Beam Processes
Published in Jiri George Drobny, Radiation Technology for Polymers, 2020
Thermoplastic elastomers (TPEs) are either block copolymers (SBS, SEBS, SEPS, TPU, COPA, and COPE) or blends, such as TPO (elastomer/hard thermoplastic, also referred to as thermoplastic olefin) and TPV (thermoplastic vulcanizate, blend of a vulcanized elastomer and a hard thermoplastic). These types represent the majority of the TPEs; other types are either specialty or small-volume materials.
Phased array ultrasonic imaging and characterization of adhesive bonding between thermoplastic composites aided by machine learning
Published in Nondestructive Testing and Evaluation, 2023
Guanyu Piao, Jorge Mateus, Jiaoyang Li, Ranjit Pachha, Parvinder Walia, Yiming Deng, Sunil Kishore Chakrapani
The objective of this work is mainly focused on the PAUT imaging to evaluate the integrity of adhesively bonded thermoplastic structures aided by ML algorithms. We investigate a sandwich structure of thermoplastic olefin (TPO) and long glass fibre polypropylene (LGFPP) that is adhesively bonded with different interfacial conditions. We focus only on the TPO-adhesive interface by developing C-Scan images of the interface using PAUT. Compared to existing research that either uses post-processing algorithms or ML algorithms, we propose a new damage index-based ML classification framework that takes advantage of the correlations between physics-based DIs and features/parameters in ML models, which can provide a higher accuracy to classify different bonding conditions even with limited data size. We present an image processing algorithm for extracting quantitative information and features from C-Scan images obtained from PAUT which categorises the bonded areas into defect, mid-level and good bonding regions spatially. Then, discrete DIs and composite DIs with different physical meanings are defined based on the three categorised images, which were used to quantitatively evaluate the sample bonding conditions.
Experimental investigation and parametric optimization of cryogenic abrasive water jet machining of nitrile rubber using Taguchi analysis
Published in Cogent Engineering, 2023
Preeti Maurya, Vijay Gaddale Srinivasa, C. Raghavendra Kamath
The machining of elastomers using traditional methods (like, Control numerical control (CNC) drilling, turning, milling, etc.) in the cryogenic environment has some problems during the process, like inferior surface finish, dimensional instability, and adiabatic shear band formation (Dhokia et al., 2011; Mallick et al., 2022). These defects are due to the cutting forces involved in traditional machining methods and workpiece fixing, necessitating a relatively strong clamping force. Over the past few decades, researchers have addressed the drawbacks of traditional cryogenic machining by making significant advancements and modifications in non-traditional machining techniques. Examples include Low-power CO2 laser cutting (Banerjee & Bhowmick, 2014), Ultra-high pressure water jet machining (Hu et al., 2014), Cryogenic-assisted air jet machining (Gradeen et al., 2014; Lou et al., 2019; Zhang et al., 2021, 2022b, 2022a), and Abrasive water jet (AWJ) machining (Kowsari et al., 2017; Maurya et al., 2022). The need for sustainable machining methods is increasing rapidly (Ozbek et al., 2021). Among the above-discussed non-traditional machining methods, abrasive water jet (AWJ) machining is an eco-friendly and environmentally secure procedure. It is a sustainable machining method in the era of green manufacturing. It is often used in manufacturing and production industries to machine several engineering materials, especially difficult-to-machine materials. Heat does not affect the process, making it less likely to impact the material’s properties. The quality of the machined component is adaptable, free from adiabatic shear band formation and can machine thick material (Khan et al., 2021; Sharma et al., 2022). The AWJ machining has two dominant jet generation variants, namely, injection-type jet and suspension-type jet. The primary benefit of a suspension-type jet is that, compared to an injection-type, it operates at a much lower operating pressure (Molitoris et al., 2016). In suspension-type, a premixing of abrasive particles with water is required before the water emerges from the orifice to form a jet. It uses a liquid suspension known as slurry, which is subsequently moved to the cutting nozzle. Many studies are available on the experimental investigation of suspension-type AWJ machining of engineering materials (Liu et al., 2022; Qiang et al., 2019; Yokomae et al., 2023). Few works on parametric analysis of suspension-type AWJ machining processes of different thermoplastics are available. Tamannaee et al. (2015) worked on suspension-type AWJ machining of Talc-filled Thermoplastic Olefin (3 mm thickness) by considering jet impingement angle as a dominant process parameter. Kowsari et al. (2017) found that the principal dominating process parameters during suspension-type AWJ machining of Polymethylmethacrylate (3 mm thickness) were the number of machining passes, traverse rate, jet impingement angle, and impact velocity. Out of the available literature, none of the studies worked on the suspension-type AWJ machining of elastomeric materials. Hence, it opens up a new field for researchers to explore the significant process parameters involved in the AWJ machining of elastomers.