Ultrasonic Machining Process Optimization by Cuckoo Search and Chicken Swarm Optimization Algorithms

1. Introduction

The development of the newer and harder materials is partly responsible for the advancement of machining technologies. The materials like ceramics, carbides, satellites, quartz, superalloys, etc., are used in many applications due to their several advantageous properties. These materials possess a very low machinability, and thus, producing complex shapes in those materials are extremely difficult with conventional machining processes. Sometimes producing a specific geometry is impossible to machine with the usual machining processes. In addition to that, the demand of higher production rate, dimensional accuracy and machining economy necessitate the use of unconventional or modern machining technologies.

Ultrasonic machining (USM) is a mechanical metal removal process for machining hard and brittle materials such as glass, ceramics, quartz, silicon etc., in which the material is removed from the workpiece surface due to brittle fracture caused by impact of abrasive grains because of tool vibrating at high frequency. Figure 1 shows a typical USM setup. The USM process starts with the conversion of low frequency electrical signal to a high frequency electrical signal, which is then fed to a transducer for getting converted to high frequency linear mechanical vibration. The vibration is then transmitted to the tool via tool holder. The tool made of ductile and tough material vibrates with high frequency and slurry of abrasive grains suspended in a liquid is fed into the cutting zone under pressure. The tool is gradually fed with uniform force. The impact from the tool propels the abrasive particles across the cutting gap, causing them to strike the workpiece (hammering and impact) which causes brittle fracture on workpiece surface, resulting in the removal of the material in the form of small wear particles which are carried away by the abrasive slurry.

Figure 1.

A typical ultrasonic machining setup