Study of the effect of machining parameters on delamination in rotary ultrasonic machining process of glass fiber reinforced polymer composite by diamond core tool

Glass fiber reinforced composites pose numerous industrial applications that are because of suitable mechanical and physical properties. Drilling is a common method to connect fiber reinforced material structures. Rotary ultrasonic machining is one of the new methods in machining of fiber reinforced composites that is highly attractive in recent years. Fiber reinforced composite laminates in machining operations, especially in drilling operations which are subjected to stress concentration, tend to be delaminated. Delamination damage is strongly influenced by factors such as tool material and geometry and also machining parameters. Therefor in recent years, new tools such as diamond core drills are used in drilling of fiber reinforced composites due to their lower force creation and simultaneous drilling operation and hole internal grinding. In this research, delamination of glass fiber reinforced composites (GFRP) with a percentage of 65% fiber in rotary ultrasonic machining process using diamond core drill regarding machining parameters have been discussed. According to conducted experiments, it was observed that cutting speed increment and feed rate reduction, decreases the delamination damage and improves hole quality. Also based on achieved results, a statistical relationship between machining parameters and delamination in Minitab software offered. According to the resulting model, cutting speed has a greater impact on the amount of delamination