XY tables are either mechanical or electromechanical machines which are commonly employed in applications which require an enhanced range of motion with accurate positioning. Thus we can say that the primary objective of an XY table is to provide an increased range of motion with very high accuracy. These machines are sometimes also referred to as XY linear stages or XY cross-slide worktables.
An XY table provides accurate motion in the horizontal plane formed by the XY axes. This motion along the XY axes is linear in nature. That is why these machines are known as XY linear stages. The X and the Y axes are perpendicular to each other. Due to these crossed axes, these machines are also known as cross-slide tables.
These machines are commonly used in CNC machining, milling, drilling, tooling, and other types of positioning applications in various types of industries. These tables are widely used in mechanical works, industries with industrial robots, industrial automation applications, and semiconductor industries.
The machine or the job piece, whose range needs to be extended, is mounted on top of the XY table. The XY table then slides over the linear bases and provides an extended range of motion for the mounted machinery in a very precise and accurate way.
Major categories of XY tables
XY tables are available in the market with a wide variety of features and characteristics. They are available in different sizes, dimensions, weights, resolutions, and loading capacities. However, the XY tables are often categorized on the basis of drive systems that they utilize. In regards to the drive system, there are two main types of XY tables which are manually operated XY tables and automatic motor operated XY tables.
A manual XY table has a pure mechanical construction and does not employ any electronic or software system within the machine. The position and the motion of the machine are controlled by an operator by means of two rotary hand wheels. One wheel controls the motion along the X-axis while the other one controls the motion along the Y-axis. These types of XY tables are often lightweight and compact in size and are used for lightweight machines and jobs.
Automatic motor controlled XY tables are electromechanical machines which utilize the power of electronics and software within the machine. These advanced machines are very fast and accurate due to the digital control system and software-based machine control. Highly accurate stepper and servo motors are used to control the position and motion of the mounted machine or the job piece. Preplanned motion paths can be provided to the machine control system which will then carry out these plans automatically. Normally these machines are faster and have increased loading capacities. Hence they are used for bigger applications or the applications which require very tight position control.
How does an XY table work?
XY tables are known as tables or stages because they consist of flat moving surfaces. The machine or the job piece, whose range needs to be extended, is mounted on top of these surfaces. The moving surface slides on top of the linear sliding bases. The sliding base is the stationary part of the machine and provides a stable base for the flat surface to move upon. The table surface slides on the linear sliding base by means of roller or ball bearings. These bearings ensure a smooth and frictionless motion of the surface.
The exact position of the moving surface and the rate of motion are controlled by the hand wheels or by the linear motors depending upon the nature of the drive system of the XY table. In case of automatic XY tables, often times sensors are provided in the machine, such as optical encoders and limit switches. Optical encoders provide accurate feedback to the motor regarding the exact position of the table. Limit switches are installed for dead-end detection so that when the table has reached the absolute limit, the motor should stop generating torque. This measure saves the motor from wearing itself out.
The function of the linear sliding base, as the name suggests, is to provide sliding linear motion to the table surface. This means that a single linear base can only move the table along a single axis. An XY table is a 2 DOF system which requires motion along to axes. To attain this multi-axis motion, two linear bases are used in conjunction. One base is mounted on top of the other. In this way, the table can be moved to any point in the XY plane within the XY limits of the XY table.
XY tables are rugged and tough machines because they are made with cast iron or stainless steel. The roller and ball bearings are also made of chrome steel or bronze. The frame is often made from aviation grade aluminum alloys.
Industrial use of XY tables
Large sized XY tables are commonly used in mechanical fabrication shops, CNC machining industries, tooling, milling and drilling applications and in conjunction with industrial robots.
Compact size and low profile XY tables are used in laser cutting, laser engraving, laser welding, semiconductor assembling, material inspection, and optical applications.