Coordinate tables, plotters and pneumatic tables

Positioning table - industrial plant, complex of equipment assigned for
traveling by adjusted trajectory of machine's working mechanism or processing
detail.

Modern positioning table is complicated mechanotronic system connecting bearing structure of support with electromechanical drive and pluriaxial supply system and executive arbitrary purpose mechanism. Using control board gives chance to automate production process completely. Processing accuracy of one or some details on sensitive table may form more than one micron by each axle with even rather high velocity.

Feeding devices for actuator's traveling and working plate (grating) for strengthening tempering detail are assembled on bearer frame. Component fixation is provided with mechanical or vacuum hold-down, or just with its own weight (rare). Work mechanism traveling along two or three coordinating axles allows us to produce plane or volume various formed components.

There are some variants of construction positioning table. Choice of construction is conditioned by its purpose and adjusted technical characteristics.

Most spread of them are cross and porta.

1. Cross construction provides great flexibility of system and is usually used for processing components with complicated spatial geometry, when the trilateral admittance to component is extremely necessary. Cross systems are used in pluriaxial milling, grinding machines or for three-dimensional object scanning, as well as they are used for work in half-finished product continuous feeding conditions (conveyor).
2. Portal type of positioning tables is used in devices aimed for processing plane surfaces, e.g. in cutting out, cutting and drilling types of machines, as well as in systems with heavy loaded horizontal axes.

Positioning table's driving gear.

1. Several types of traditional gearing are used in positioning table's driving gear:
• Toothed belt
• A couple of pinions - rack and screw-nut
• Ball screw couple
• Line driving gear system with direct conversion engine of electromagnetic energy to line shifting.
2. Feeding assemblies.
   As feeding assemblies in such systems are usually used:
• Stepper motor
• Synchronous motor
• Nonsynchronous motors with feedback (it is allowed application in systems which don't experience high dynamic loads)

Most perfect technical solution for positioning tables is nowadays straight (linear) driving gear. Its working principle is concluded in immediate transformation electromagnetic energy to linear or rotary motion energy.

This driving gear provides actually the best indices with such parameters as exactness, dynamic acceleration and braking, work speed, reiteration. There are no adjustable parts in linear engine which are liable to deterioration and rubbing that's why the characteristics of driving gear practically don't change with time. There is only one drawback in linear engine: it is high price, that's why its application is economically justified only in exacting velocity coordinating systems.

Control system

Control system of coordinating drive gear is intended for controlling the laser processing table in problems of laser cutting and engraving. Hardware and program control system means allows you to adapt it for using coordinating drive's different construction, solving problems of controlling plasma arc cutting machines, laser marking, etc. Driving gear and positioning table mechanisms control is realized with the help of control board. They are devided according to formation the control signal in three groups: analog, impact and numerical.

1. Analogue systems of board control are nowadays most spread and widely used in mechanical engineering. Nevertheless their use isn't always possible in systems that are working at high velocity, because of their limited performance.
2. Impact systems are used for stepper motor control or synchronous motor with impact admission. Their characteristics are inferior to numerical, but as long as such devices' price is much lower, they are usually used in budgetary systems, that don't demand high positional accuracy and feedback.
3. Modern numerical systems become nowadays more and more spread
   because of broad possibilities for signal processing, interface conveniences, noise immunity.