The Effect of Chilled Air on Burr Formation When Drilling Aluminium Alloy in Manufacturing Industry

Abstract

Burr formation is a major challenge during drilling which could cause poor assembly and may lead to part rejection. One of the factors which could result in an increment of burr height and deteriorating the hole quality is poor selection of cutting parameters and drilling environment. aluminium alloy (Al7075) is usually drilled in dry condition due to the concern over the use and disposal of cutting fluid which could lead to environmental pollution. However, dry drilling can cause high heat generation which can highly influence the burr formation. Therefore, this research aims to investigate the effectiveness of chilled air as a cooling medium in drilling Al7075 to improve the machined surface integrity in aspects of burr formation. Drilling operations of Al7075 were performed at cutting speeds and feed rates of 82 - 123 m/min and 0.01 - 0.1 mm/rev. The lowest burr height was obtained when drilling using the higher cutting speed and feed rate of 123 m/min and 0.01 mm/rev. Whereas, the lowest burr thickness was obtained when drilling using the lower cutting speed and feed rate of 82 m/min and 0.01 mm/rev. This indicates that the use of chilled air when drilling Al7075 is favorable to reduce the burr formation at higher cutting speed and feed rate hence improving the productivity.