Skip to content

Okuma’s 5-Axis Glossary: Terms You Need to Know

By Okuma Sponsored Content

For manufacturers using 5-axis machines and the associated processes for the first time, learning the language of 5-axis machining may be overwhelming. We’re here to help shortcut your learning curve and expand your knowledge with a quick glossary of 5-axis machining terms and their definitions. 

3+2 Machining

The 3+2 machining process, also referred to as positional 5-axis machining, allows for a workpiece to be machined from all sides using five axes at different points in the machining process. The fourth and fifth rotary axes (chosen from the A, B, and C axes) keep the part in a fixed orientation, then typical 3-axis machining can be carried out.

Simultaneous 5-Axis

Simultaneous 5-axis machining involves 5-axis machines moving the cutting tool on the X, Y, and Z axes and rotating two of the A, B, and C axes to maintain continuous contact between the tool and work piece. This differentiates simultaneous 5-axis machining from 3+2 operations, since with 3+2 machining, the part is in a fixed orientation. Nowadays, most machine tool builders possess software that performs simultaneous 5-axis.  At Okuma, we use the phrase TCPC (tool center point control) to describe our simultaneous 5-axis machining.

A, B, and C-Axes

5-axis configurations always involve the use of the X, Y, and Z-axes along with two other axes chosen from the A, B, and C-axes. The A, B, and C-axes used vary depending on the style of machine. A trunnion-style machine operates with an A-axis and a C-axis, while a swivel-rotate-style machine uses a B-axis and a C-axis.

X, Y, and Z-Axes

The X, Y, and Z axes are the three planes that occupy three-dimensional space. Known as the Cartesian coordinate system, these axes are used in many branches of mathematics to graph functions. In manufacturing, these axes are used to design part geometries that utilize multiple axes.


Non-uniform rational basis spline (NURBS) is a mathematical model used to represent curves and surfaces. NURBS is part of an industry-wide standard of modeling used in computer-aided manufacturing (CAM) software to map surfaces in three-dimensional spaces. These models are useful in 5-axis machining to visualize the pathways of curved surfaces that multiple axes will machine during the 5-axis process.

Tool Vectors

When programming in 5-axis, we have two distinct options that we can use to command rotary moves and positions. We can output the data using either rotary angles or tool vectors.

Using IJK Tool Vectors makes the program independent of any particular machine configuration. Since we aren’t commanding any specific axis callout (A, B, or C), the machine is free to use whatever axes it has available to position the tool to its commanded position and tilt angle. This freedom allows the same part program to be shared among several different machines in the shop – regardless of the machine configuration – and can offer a tremendous amount of freedom when scheduling jobs on the shop floor.


A singularity is a point in space where nothing moves – think of a black hole, where objects move around it but the object itself is stationary. In machining, a singularity reflects the same concept, where a tool is spinning but the center is hardly moving,

The tool that is affected by this is the ball cutter, and in many cases, manufacturers will tilt the tool to avoid the slow RPMs at the center of the tool, particularly during the finishing cycle.

  • View All Articles
  • Connect With Us

Always Stay Informed

Receive the latest manufacturing news and technical information by subscribing to our monthly and quarterly magazines, weekly and monthly eNewsletters, and podcast channel.