Introduction to XYZ axis systems

XYZ axis stages are very popular and widely used industrial devices. These are also known as XYZ translation systems or XYZ linear stages. An XYZ axis stage is primarily a mechanical/electromechanical device which provides linear translation along three axis for the purpose of motion control, position control, and range extrapolation. These devices are 3 DOF (degrees of freedom) devices because they provide motion in three axis.

XYZ axis stages are commonly used in industries and research settings to control the motion and adjust the position of a machine tool or a job piece. The job or machine tool is mounted on the moving platform of the machine. The motion of the platform is then controlled either manually or through linear motors.

XYZ axis systems are highly accurate and precise machines which have resolutions in order of a few micrometers. They are used in applications where a very strict and tight position and motion control is required.

XYZ axis systems are available in a wide range of features, sizes, and capabilities. From very heavy CNC machines and industrial robots to very tiny microchips and lenses, XYZ axis systems are available to fulfill all types of industrial and research requirements. These systems are very commonly used in mechanical workshops, fabrication facilities, machining and tooling factories, manufacturing industries and system integration facilities.

Figure 1:

Categories of XYZ axis systems

There are two major categories of XYZ axis systems.

  1. Manual systems
  2. Motorized systems

The manual XYZ axis systems are mechanical XYZ systems which require an operator for their operation. Rotary hand wheels are provided on each axis of the machine. The translation of the platform along a particular axis is achieved by rotating the hand wheel associated with that axis. In miniature type XYZ axis systems, small knobs are provided which serve the same purpose. One rotation of the hand wheel graduates the platform in order of a fraction of a micrometer. The graduation is measured by means of a scale or a gauge present on the machine.  

The motorized XYZ axis systems are automatic systems which are electromechanical in nature. These systems fall under the category of mechatronic systems which is a combination of mechanical, electronic and software systems. These type of XYZ systems utilize very accurate linear servo motors for the purpose of motion and position control. An embedded control system is present on board which controls the motion of the servo motors in a very precise manner. These systems can be interfaced to a PC and a preplanned motion path plan can be given to the XYZ system which it executes automatically.

Mechanism of XYZ axis systems

The job or the machine tool, whose position is meant to be controlled, is mounted on the flat platform provided on the XYZ stage. This platform is dynamic and can be graduated along any of the three axis. The linear motion of the mounting platform occurs by sliding over the linear sliding bases which remain stationary. The platform translates over the linear sliding bases by means of a cross roller guide. The mounting platform can be moved to any point within the XYZ plane in the limits of the machine.

One of the most crucial parts of an XYZ system is the drive system. The drive system of the machine determines the response time, speed, accuracy, precision, and performance of the XYZ system. The motorized variants of the XYZ systems have a servo/stepper motor based drive system. These motors are very accurate and therefore, this type of electronic drive system is far more superior compared to the mechanical drive system. The motion of the servo motors is controlled by an embedded control system. This digital electronic control system is built around a microprocessor or a microcontroller microchip. The control system gets motion and position feedback from an optical encoder with very high resolution. The optical encoder has a resolution usually in the range of several nanometers. In addition to that, more sophisticated XYZ systems also employ additional reflective or laser type homing and limiting sensors. These sensors detect the homing position and the dead ends of the machine.

The heavy-duty variants of the XYZ axis systems are built from cast iron or stainless steel alloys. These materials provide strength, durability and higher loading capacities. Miniature and smaller variants of the XYZ axis systems are built from aluminum alloys. This makes the systems very lightweight and agile. For parts which require frictionless motion, chrome steel alloys are used.

Figure 2:

Applications areas of XYZ axis systems

XYZ axis systems are used in manufacturing and fabrication industries for CNC machining, tooling, drilling, engraving and cutting applications. The miniature versions of these machines are used in laser cutting, laser welding, electronics assembling, SMT soldering, optical alignment, and micromachining applications.

Figure 3: