The Beginner’s Guide to Machine Turning Operations


Along with drilling and milling, turning is a common machining process used in the manufacturing industry. It involves the use of a tool bit to selectively cut away material from a rotating workpiece. The workpiece is placed inside a turning machine where it rotates or “turns,” allowing the tool bit to trim it do the desired shape and size.

The 3 Types of Turning Operations

There are three main types of turning operations. Tapered turning is used to produce cylindrical shapes by trimming away excess material. There’s also spherical generation turning, which as the name suggests, it used to produce spherical shapes. Spherical generating turning is typically performed using a CNC machine or hydraulic attachment. And hard turning is a process that involves cutting particularly hard materials measuring higher than 45 on the Rockwell Scale.

How Turning Is Performed

Turning is performed in one of two ways: manual or automatic. In the past, manufacturers and other companies relied strictly on manual turning. Manual turning requires a human worker to continually adjust the machine and/or workpiece. Automatic turning, however, streamlines turning processes using a computer numerical control (CNC) system. It’s a faster and more efficient solution that’s become increasingly popular among manufacturers in recent years. Human workers must still specify the workpiece’s specifications in a computer program, but CNC machines will translate these specifications into the appropriate turning operations.

Factors Affecting Turning Operations

Several factors can affect turning operations, one of which is the speed at which the workpiece rotates. The faster it rotates, the easier it is to remove material. Of course, the material from which the workpiece is made will also affect turning operations. Turning can be performed on a variety of materials, including plastic and wood as well as metal and stone. Stronger materials often require diamond-tipped cutting tools to effectively trim the unwanted, excess material from the workpiece.

Turning vs Milling: What’s the Difference

The terms “turning” and “milling” are often used interchangeably when referring to machining processes that involve the removal of material through rotation. However, these are two unique machining processes with their own characteristics. The primary different between turning and milling is that the workpiece rotates with turning, whereas the tool bit rotates with milling. To perform milling, manufacturers place the workpiece in a turning machine where the tool bit rotates rather than the workpiece itself. In comparison, the workpiece rotates with turning while the tool bit remains stationary.