Guide way

1. What is a guide way?

The guide way is an important component determining the motion characteristics of machine tools. Therefore, it is necessary to understand the characteristics of the guide way and choose a machine that meets the specific machining process.

A guide way is a mechanism that guides the feed system of a machine tool to move accurately towards a specified axis direction. For example, the guide way of the X-axis allows the table or milling head to move only along the X-axis direction, and constrains it not to move along the Y-axis or Z-axis direction.

The guide way can be roughly divided into two categories. One is a prismatic guide way, and the other is a linear motion guide way. The difference is the size of the contact surface. The prismatic guide way is in direct contact between surfaces, and a linear motion guide way contacts at a line or a point between surfaces, using bearings as a medium.

Compared to the linear motion guide way, a prismatic guide way have the following characteristics:

• Due to the high friction coefficient, the force required for axis moving is greater. Especially at the moment of starting feeding in a stationary state, the friction coefficient will undergo significant changes, making it relatively difficult to determine the position of the minimum increment unit (in micrometers) under specific conditions.
• Due to wide contact surface, it is stable, and has high rigidity. This characteristic means strong resistance to external disturbances. For areas such as free surfaces that require continuity of machining surfaces, and for areas with significant changes in cutting load within the same machining process, the prismatic guide way is relatively advantageous.
• A prismatic guide way needs some craftmanship to get higher the contact rate between surfaces by over 80%. Therefore, the performance of the machine is influenced by human factors.

2. Types of guide way

2.1 Prismatic guide way

2.1.1 Box way

2.1.2 Dovetail

2.1.3 Vee

2.1.4 Round

2.1.5 Hydrostatics)

2.2 Linar motion guide way

2.2.1 Ball bearing linar motion guide way

2.2.2 Roller bearing linar motion guide way

2.3 Hybrid guide way

On the same axis, sometimes a mixture of prismatic guide ways and linear motion guide ways is used. In most cases, the prismatic guide ways is responsible for the main role, while the linear motion guide ways is used to support.