Introduction to Rotary Indexers

Wafer dicing during semiconductor integrated circuits (IC) fabrication is the process of separating the individual ICs from the die through slicing. IC manufacturing uses a rotary indexing table to achieve the precision positioning and accurate stepping of the die for slicing. Generally speaking, indexers are useful for any manufacturing process that requires repeating operations at multiple spots on a workpiece.

What Is a Rotary Indexing Table?

Tooling work in manufacturing operations—like die slicing for IC fabrication—often requires repeated rotational repositioning of the part being worked on. This repositioning operation is called rotary indexing and conducted by a machine called a rotary indexing table or rotary indexer.

The rotary indexer mainly performs two tasks:

• First, it positions the part for the tool by rotating it by the required angle.
• Then it firmly holds the workpiece in place while the tool works on the current spot. The part goes through a series of partial rotations for positioning and motionless stops for tool work until the entire part has been worked on.

Due to the precise positioning required for operations like wafer dicing in IC manufacturing, rotary indexers themselves need to be extremely precise machines. Consequently, they have sophisticated designs involving electrical motors and motion transmitters controlled by well-calibrated servomechanisms or cams. The assembly also includes rotational position sensors and encoders that assist with achieving precise positions.

In addition to manufacturing operations, rotary indexing tables are also used for inspection and quality control of finished parts. They are also helpful in assembly operations that require parts to be moved through a series of workstations. Commercial operations like packaging, bottling, and machining frequently rely on rotary indexers.

How Does a Rotary Indexer Work?

Rotary indexers fall into two design categories: servo rotary tables and cam indexing devices.

Servo rotary tables are used for applications that require:

• Quick positioning

• Short settling times

• Minimal backlash

• Long pauses between angular movements

The servo mechanism relies on encoders that provide fast electronic feedback to achieve quick and accurate positioning.

Cam indexing devices use mechanical cams instead of servomechanisms to position the rotary table. The sensor packaging for cam indexers consists of inexpensive camshaft sensors. Cam indexers are cheaper than servo indexers because of the low cost of the sensors used in them. Cam rotary indexing tables are suitable for applications that possess equidistant angular positions.

Rotary tables are usually mounted horizontally but vertical mounting is also possible if the application requires it. The mounting of the table depends on many factors, especially the axial, moment, radial, and torque loads necessary for the application.

AIM Joraco: Premier Rotary Indexer Manufacturer

AIM Joraco is an industry leading supplier of rotary indexers. We manufacture standalone and benchtop rotary indexers:

• Standalone Indexers: Our fully pneumatic TOGGLE-AIRE® Model 1011 line of rotary indexing tables provide smooth indexing. Some of the aspects of these models can be customized, such as center distances, strokes, and tooling plates. They come with easy-to-operate speed controls and emergency stop mechanisms for operator safety. You can download the full set of operating instructions here.
• Benchtop Indexers: Our TOGGLE-AIRE® Model 2000 is a compact rotary indexing table built as a single piece that fits into the frame of a 3-ton press. This machine provides powerful but smooth indexing operations using an air driven clutch fabricated from high-quality heat-treated machine steel. This is a very robust and durable machine, as evidenced by this video of a Model 2000-5 that has been running for over 12 years for a total of 25 million cycles.

For more information about our rotary indexers or other equipment and services, please contact us.