A control chart for drilling bun formation for low alloy steel, AISI 4118,
was developed. A drilling burr control chart, based on experimental data, i
s a tool for the prediction and control of drilling burrs. High-speed steel
split-point twist drills with different diameters were used for the tests.
Fun classification was carried out based on the geometric characteristics,
bun formation mechanisms, and sizes of the burrs. Four different bun types
such as uniform bun (Types I and II), transient burn and crown bun were fo
und. New parameters consisting of process parameters and drill diameter wer
e developed, and used to show a unique distribution of the bun types. Bun t
ypes and the resultant bun size showed great dependence on the new paramete
rs regardless of the drill diameter. Through thr chart, bun type can be pre
dicted as a function of given cutting conditions. Also, cutting conditions
that are believed to create preferred bun types can be selected. (C) 2001 E
lsevier Science B.V. All rights reserved.