A novel investigation of sacrificing layer effect on micro-channel fabrication of glass using rotary ultrasonic machining

• Published in: Journal of the Brazilian Society of Mechanical Sciences and Engineering 2023-07, Vol.45 (7), Article 350
• Main Authors: Rai, Shardul, Vishnoi, Mohit, Mamatha, T. G.
• Format: Article
• Language: English
• Subjects: Acids; Brittle materials; Coating effects; Design optimization; Engineering; Feed rate; Mechanical Engineering; Microchannels; Orthogonal arrays; Process parameters; Protective coatings; Reduction; Soda-lime glass; Substrates; Surface finish; Technical Paper; Thickness; Ultrasonic machining; Waxes; Workpieces
• ISSN: 1678-5878; 1806-3691
• DOI: 10.1007/s40430-023-04273-z

During micro-ultrasonic machining of brittle materials, lateral vibration of the tool and errors due to the placement of the workpiece leads to overcut and surface damage. Hence, this paper presents an effective method for micro-channel fabrication using a sacrificing coating on the substrate material. The myristic acid, along with PE wax, has been used as the sacrificing layer. Soda-lime glass with 110 mm × 70 mm × 2 mm dimensions has been used as the substrate material. The coating thickness (0.5 mm, 1 mm, 1.5 mm), coating type (PE wax and myristic acid), and feed rate (1 mm/min, 2 mm/min and 3 mm/min) have been considered as process parameters. Some other fixed parameters that have been taken into consideration are amplitude, frequency, and tool rotation with magnitude 1.3 µm, 20.81 kHz, and 1500 RPM, respectively. Micro-channel of 3 mm length, 1.6 mm width, and 0.3 mm depth has been fabricated on the soda-lime glass using micro-USM. Taguchi L9 orthogonal array has been used for the design of the experiment and optimization of process/machining parameters. The effect of coating material while micro-USM has been compared based on performance parameters: (i) overcut and (ii) stray cut. The machining parameters: (i) coating thickness and (ii) feed rate, showed a significant effect on surface finish. Minimum overcut was observed with 1 mm myristic acid coating and 2 mm/min feed rate, whereas a minimum stray cut was observed with 1 mm PE wax coating and 2 mm/min feed rate. Myristic acid coating was found to be more effective for overcut reduction, whereas PE wax coating had more impact on stray cut reduction. The experiment has been designed and performed to bring in limelight the effectiveness of myristic acid for enhancement of overall surface finish of the substrate material. The conclusions derived from the experiment have been in the favor of myristic acid being an effective coating material.