How Do Rotary Indexing Tables Work

If you venturing into precise machining or fabrication, then rotary indexing table offers perfect solution for you.

But, how does rotary indexing table work? What are the basic principles behind successful machining process?

Well, this guide explores all fundamental aspects about these machines – let’s dive right in:

What is Rotary Indexing Table?

A rotary indexing table is an electromechanical with rotating tooling system. The machine rotates tooling system or workpiece with unmatched precision.

The indexing table features evenly spaced stations with clumps or fixtures securely holding workpieces during operations.

Rotary Indexing Machine

Rotary Indexing Machine

Working Principle of Rotary Indexing Table

Here’s a step-by-step process detailing how a rotary indexing table works:

Indexing Table

Indexing Table

Step 1: Initial Positioning

The run begins with the rotary indexing table bucket in its neutral position. The selection of the indexing mode can be realized manually by a skilled operator. This is where we have the manual rotary indexing table.

Alternatively, it can be realized automatically by a feedback controller, depending on the type of programmable indexing table. Among the most common options are the servo driven rotary indexing table.

Step 2: Loading

The items or the tool are loaded into the rotary indexing table. This can be realized by having an operator do it manually or by having automation integrated with the system so that the feeding mechanism is used.

Step 3: Rotation Initiation

The workpieces (parts or tools) are being loaded into the indexing table and now the rotation is initiated. In the case of motorized indexing tables, the rotation is powered by the motor and drive system regulating. The table may rotate at a steady speed or periodically, in accordance with the standards of the specific application.

A practical example is the rotary indexing table for milling machine which guarantees high accuracy and consistency.

Step 4: Indexing

A stoppage of rotating indexing table occurs randomly at specific angles, which is defined beforehand. This stat and reposition are the main role of the indexing system built into the tables. The mechanical indexing mechanism guarantees that table will stop exactly at each desired position. This allows for performing essential operations on workpieces or cutting tools that require high accuracy.

Step 5: Operations

Inductive automation abstracts several operations at indexed location. The tooling and pieces can be acted upon. These could include a variety of operations such as machining, assembly, inspection, welding and any other works relative to an application.

The indexing table mechanism operation type will depend on whether there is a particular robotic operation. Usually, this is fit for the specific milling manufacturing process. Of course, the accuracy will depend certain variables such as rotary index table torque calculation.

Step 6: Repeat

Following the work process at one indexed position, the table indexing continues to rotate to the following one. This procedure keeps on continuously till the period in which all desirable operations are done on workpieces/ tools.

Step 7: Unloading

Hence, after the final machining operation, the workpieces or tools are lifted off of the rotary indexing table. Similarly, to the charging process, unloading is possible involving a person or a robot, who is going to be integrated with the combi mechanism.

Step 8: Reset

Once unload is completed, the rotary indexing table is going to be set back to its original position. So that the next cycle can be prepared for. This reboot can be done in different ways: either manually or automatically, it matters how the application is used.

Step 9: Maintenance and Monitoring

It is important to take proper care during continuous and cyclic movements of rotary indexing table.This involves maintaining all kinds of activities for the best performance and prolong the life. The monitoring should take place on a regular basis. Monitoring is done in order to check whether all hardware components are lubricated and component failures have been debugged.

How Different Rotary Indexing Table Technologies Work

Rotary Indexing Table Structure

Rotary Indexing Table Structure

Pneumatic Rotary Indexing Table

A pneumatic rotary table operates by using compressed air as a tool for a table lock and for transmission of respective positions dictated to it.

The pneumatic indexing rotary table comes with pneumatic actuators or cylinders to provide the actuation forces. Installed on the end, these pistons are powered by compressed air, supplied by the pneumatic lines connected to the air compressor.

Table will start from its default placements that is aligned in most cases with a reference point or marker. Air flow is applied to the actuators and the actuators are used to pump the table to producea rotating motion. The rotation of the table is driven by air pressure into the actuators to either contract or stretch. The air pressure is regulated by the air pressure regulator (inertial measurement unit). The air pressure is between the actuator and the air pressure regulator (IMU).

At these positions, a servomotor brings in and feed the cell slide into the focal plane which will be automatically indexed. The mechanism of indexing not only stops the table at desired magnitude but also ensures that it stands at the specified places.

Servo Rotary Indexing Table

The servo rotary indexing table uses a servo motor and a control system to maintain real-time and accurate rotation control as well multilateral indexing positions.

The servo rotary table is an auxiliary unit, which features one or more servomotors. These motors are the actual power unit required to rotate the table and allow it to place the predetermined position.

The drift table gets to its starting point as defined by the aligning of the cells or references. This setup can be either manually tweaked or auto controlled using Servo Motor electronic mechanism.

The motors are controlled by a complex control device. For instance, it can be composed of a Programable Logic Controller (PLC) or a Computer Numeric Control (CNC) system. With this control system, input signals become operative in making the actuaries move the robotic arm in the required directions.

The control system sends the command toservo motors via the corresponding signals and begins the rotational movement of the table. While the servo motors are turning the table, the high precision and accuracy of the motion is guaranteed.

The table is turned to arrive at fixed indexing positions; these positions are calculated previously. Sensors track the position of the mentioned table and adjust the frequency of servo motors based on feedback to guarantee accurate indexing.

Motor Rotary Indexing Table

In motor rotary indexing table, the indexing table moves virtue of the motor electrical driving force which drives its rotational positioning/movement.

The data rotary indexing table is equipped with the electric motor, the most common types of which are stepper or servo motor. This is the work that helps to spin the table and to place it in the exact desired position.

Control of process happens at some control system which may be a programmable logic controller (PLC) or computerized numerical control (CNC). A feedback vessel of this system has several signal inputs that indicate the aimed position of the table.

While the indexing is progressing, the control system transmits signals to the electric motor to begin its rotation. The movement of the machine is regulated by the motor, causing the necessary indexing.

The rotating table in turn gets to its pre-determined mounting points. The computational method is the type of control that is determined by the system if the requirements are met. The set authority is in charge of the control system, which is all the time observing the position of the table and making categorical changes in the motor’s output.

Some of the screw, or rotation-table indexing tables may be provided with position feedback devices like encoders or sensors. These components involve closing feedbacks in the control system.Which also provide the actual positioning of the table to be checked by the system. The system will output the right directions to the motor to keep the position in the required value.


Rotary indexing tables are critical in various manufacturing process for purposes such as high efficiency, accuracy and throughput. This is achieved through automation and repeatable operations. As a manufacturer, you need to get to understand the limitations and capabilities of these devices for better and informed decisions before intreating them into your production processes.

More Resources:

CNC Milling with Rotary Table – Source: TSINFA

Rotary Table for Milling – Source: TSINFA