Copyright Goodheart-Willcox Co., Inc. Chapter 9 CNC Mill Programming 197 X.1 Z−.010 X−.9 Z–.060 X.1 Z−.115 X−.9 Z−.165 X.1 Z−.220 X−.9 Z−.270 X.1 Z−.320 X−.9 Z−.375 X−1. Y−.5 F61.12 X1. Y−.25 X−1. Y0. X1. Y.25 X−1. Y.4999 X1. G0 Z.25 G0 X0. Y.25 G1 Z−.375 F60. (Finish contour) G41 D1 Y.75 X−1.25 Y−.75 X1.25 Y.75 X0. G40 Y.25 G0 Z.25 M9 G91 G28 Z0. M5 M30 9.8 Canned Cycles Canned cycles reduce repetitive amounts of machine code and make edit- ing repetitive steps easy. For instance, hole making is a common process in milling, and writing identical code for multiple holes in a single part can be tedious and prone to program errors. Canned cycles allow a single line of code to define multiple parameters, and then all subsequent holes can be positioned in the proper X and Y location to repeat the process. 9.8.1 G83 Cycle (Full Retract Peck Drilling) G83, one of the most common drilling canned cycles, is a peck drilling cycle, meaning it should be used whenever the depth of the hole is four or more times greater than the diameter of the drill. An example would be