OVERVIEW

Machining holes is probably the most common operation, mainly done on CNC milling machines and machining centers, as well as CNC lathes with milling axes. Even in industries traditionally known for their complex parts, such as aircraft and aerospace components manufacturing, electronics, instrumentation, optical or mold making industries, machining holes is a vital part of the manufacturing process.

When we think of what machining holes actually means, we probably think first of such operations as center drilling, spot drilling, and standard drilling, using common tools. However, this category is much wider. Many related operations also belong to this group of machining holes. Standard center drilling, spot drilling and drilling are used together with related operations such as reaming, tapping, single point boring, boring with block tools, countersinking and counterboring, spotfacing and even backboring.

Machining one simple hole may require only one tool but a precise and complex hole may require several tools to be completed. Number of holes required for a given job is important for selection of proper programming approach.

Even holes machined with the same tool may be different. Holes having the same diameter may have a variable depth, they may even be at different depths of the part. If all possible combinations are considered, it is easy to realize that making one hole may be a simple matter, but making a series of many different hole operations in a single program requires a well planned and organized approach.

In majority ofprogramming applications, hole operations offer a...