Six degrees of freedom (6DoF) explained

What is 6DoF?

Any machine or motion system has differences between the way that it's designed to move and the way that it moves in reality. In many cases, the planned motion is to travel along a perfectly straight line until the exact target distance has been reached.

However, in practice there will always be six different types of error in the linear motion. These are:

• linear
• horizontal straightness
• vertical straightness
• pitch
• yaw
• roll

For systems with more than one linear motion path (e.g. a three axis CNC machine tool) the six types of error in each path will add together to form the overall motion error.

Throughout manufacturing, and also beyond, accuracy of linear motion is the foundation of any process. Traditionally, the main focus in manufacturing has been to measure, control and correct for the linear error in linear motion paths.

However, even if it was possible to fully eradicate linear error, there would still be five other types of error when comparing the planned motion with reality. Therefore, with rising accuracy demands in modern manufacturing, the error measurement of all six degrees of freedom is vital.