Understanding Indexing Gear Box Technology for Automation

Understanding Indexing Gear Boxes

Indexing gear boxes play a vital role in many automated production processes. These specialized mechanical assemblies allow parts to be rotated or moved sequentially between workstations in applications like machining, assembly, labeling, and packaging. With precision timing and motion control, indexing gear boxes bring speed, accuracy, and flexibility to manufacturing operations.

What is an Indexing Gear Box?

An indexing gear box is a type of low-speed, high-torque rotary actuator. It uses a precision gear train to turn an output shaft in incremental steps. This shaft rotation can then be used to index or position parts, tools, or other fixtures for sequential processing.

Indexing gear boxes come in different configurations but generally consist of a motor, input shaft, worm gear, index plates, indexing mechanism like a geneva wheel or intermittent motion device, and an output shaft or table.

Types of Indexing Gear Boxes

There are two primary categories of indexing gear boxes:

• Intermittent or Start-Stop Motion
• Continuous Motion

Intermittent motion indexing tables use mechanisms like the geneva wheel, maltese cross, or barrel cam to create an incremental rotary movement. The output shaft turns a precisely controlled amount and then dwells before the next index.

For continuous motion, the output turns constantly but at an adjustable variable speed. This allows faster indexing for high-volume applications.

Indexing Methods

Indexing gear boxes use different mechanical methods to achieve incremental positioning:

• Geneva Wheel - The geneva wheel mechanism is very popular for intermittent indexing applications. As the input wheel rotates, curved slots engage pins in the geneva wheel to turn it in precise increments.
• Maltese Cross - The maltese cross converter translates continuous input motion into intermittent output motion. Locking arms engage grooves in the output shaft hub.
• Barrel Cam - Much like the maltese cross, the barrel cam mechanism locks the output shaft into position and indexes on each rotation.
• Ratchet - A ratcheting mechanism can provide basic low-cost indexing with adjustable stroke lengths.
• Dwell Control - For variable dwell timing between indexes, programmable motion controllers adjust output shaft pause durations.

Benefits of Using Indexing Gear Boxes

Indexing gear boxes deliver key advantages for automated factories:

Precision

With hardened gear trains and precision indexing components, indexing tables provide incredibly accurate and repeatable positioning. This allows manufacturing processes to achieve tighter tolerances.

Flexibility

Unlike fixed automation equipment, indexing tables with changeover parts can adapt to handle different products. Quick adjustments support more product variations.

Speed

Indexing mechanisms allow rapid rotation between workstations to maximize output. Faster indexing, even by fractions of seconds, boosts production rates.

Control Integration

Modern programmable indexing gear boxes seamlessly integrate with industrial controls and sensors for automation sequencing. This facilitates data collection too.

Applications of Indexing Gear Boxes

Indexing rotary tables enhance many applications:

Machining

For CNC machining, an indexing table allows cutting sequential features on multiple sides of parts. The table indexes between cutting operations.

Assembly & Inspection

Indexing systems transport parts between automated assembly, testing, or inspection stations for faster processing.

Labeling & Marking

Indexing tables rotate products as stationary print heads add labels, ink marks, or other identifiers.

Packaging & Palletizing

For packaging lines or palletizing systems, intermittent motion builds patterns of cartons on transport pallets.

Implementing Indexing Gear Box Solutions

Optimizing a production line with indexing gear box technology entails key considerations:

Speed & Throughput Requirements

Match the indexing gear box performance to application speed and volume demands. Evaluate parts handling requirements too.

Precision Indexing & Repeatability Needs

Choose indexing methods and components that deliver suitable incremental accuracy and consistency.

Controls Integration & Data Interface

Select programmable indexing tables compatible with existing industrial controls and support data needs.

Changeover, Maintenance & Support Factors

Factor in change part kits for flexibility and evaluate the gear box's durability & serviceability.

With attention to these key factors, factories can achieve tremendous gains with automated precision indexing systems.

FAQs

What is dwell time in an indexing gear box?

Dwell time refers to the pause between rotational indexes of the output shaft. This allows work to occur on a part before the table indexes to the next position.

How accurate are indexing gear boxes?

Precision indexing gear boxes provide incredibly accurate and repeatable positioning, with some systems achieving tolerances tighter than 0.001 inches.

Can indexing tables handle heavy loads?

Yes, heavy duty indexing gear boxes are available that can handle very large loads up to several tons while still providing precise incremental motion.

What motors work with indexing gear boxes?

Servo motors, stepper motors, pneumatic motors or standard AC motors can provide input drive power to suit different indexing gear box applications.

Are there safety standards for indexing gear boxes?

Yes, standards like ISO 15536-1 help define safety requirements for the design and implementation of indexing tables and intermittent motion machinery.