A Brief Introduction to Rotary Tables
A rotary table is a measurement device used mainly in the metal working field. It allows the operator to cut or drill work at precise intervals around an adjustable axis. This is done by rotating a tool in a circular motion around the work place axis with the help of a screw threaded variable drive. This results in cutting, grinding or drilling work in a smooth and accurate manner.
In general the rotary table consists of two main parts namely the pedestal and the base. The pedestal, which is the seat, is mounted on to a fixed base that is firmly attached to the floor. It has a hole in its bottom side for mounting the drilling heads. In some rotary tables the pedestal is designed to be removable and built up into a bench top form. In such a case the base and the seat are mounted in a separate fixture.
Pedestals are generally circular and are made of either steel or brass. In some rotary tables, the hole in the bottom side allows the workpiece to rotate vertically and hence the work can be drilled, cut or stroked in any direction at any angle. This feature is particularly useful when the rotary table works with a small cutting head. Similarly it can also be used to slice material.
The other main part of the rotary tables consists of a number of wheels and shafts that are fixed to the table in a horizontal position. These allow for the easy indexing of workpieces. The most common method of horizontal axis indexing is with the use of a pinion or rack alignment head that is fixed to the table. This head allows the work to be placed at any suitable location and then the operator manually or automatically shifts the table to the appropriate horizontal axis position. The shaft and wheels are then aligned so that the work is again in the desired position.
A further type of rotary table includes the self-aligned type, which is similar to the self-casting screw pump. The main difference between these two is that the worm gear on the self-aligned rotary table moves through an electric worm drive and not through a casting cone like the screw pumps. The self-aligned worm gear is mounted inside a housing that is either fitted to the table itself or mounted on a spindle arm. The worm gear rolls on ball bearings that are mounted either on the table surface or within an internal sleeve.
The main advantage of a rotary table over a milling machine is the ability to regulate speeds and precision. The operator can set the speed of the motor accordingly to ensure that the same amount of work is produced at all times. Furthermore, it is possible to precisely machinate certain workplaces because the worm gear can be manually or automatically adjusted. These features make rotary tables very popular in the production environment.