Benefits of Auxiliary Axis Integration for Rotary Indexers

Why Integrate an Auxiliary Axis with a Rotary Indexer?

Rotary indexers provide fast, repeatable, and highly accurate positioning for robotic systems. When equipped with a robot-controlled auxiliary axis, these indexers act as an extension of the robot itself—allowing seamless coordination between movement, rotation, and tool position.

Key benefits of auxiliary axis integration include:

• Increased precision: The robot and indexer move as one synchronized unit.

• Faster cycle times: Coordinated axis control eliminates unnecessary pauses and repositioning.

• Simplified control architecture: Operated via a simple open-loop VFD controller and explosion-proof AC motor.

• Reduced costs: No need for reprogramming, switchovers, or relocating robots between stations.

• Improved flexibility: Supports complex assembly, welding, and inspection tasks within a compact footprint.

By eliminating multiple setups and machine transitions, manufacturers can maintain continuous production flow while minimizing operational costs.

Built for Precision and Durability

Motion Index Drives designs and manufactures auxiliary-axis-compatible rotary index tables with exceptional accuracy and zero backlash.

This precision comes from advanced cam indexing technology, where multiple cam followers are arranged around the outer diameter of the rotating dial to provide:

• Maximum strength relative to table size

• Zero-backlash motion transmission

• High rigidity for heavy-duty applications

The result is smooth, vibration-free operation and repeatable accuracy, even in high-torque applications.

How to Size an Application for an Auxiliary Axis

Proper sizing is critical to ensure performance, safety, and longevity. The mass moment of inertia is the primary factor used to determine:

• How fast a load can rotate over a given angle

• How quickly it can stop safely

• How the inertia mismatch between the robot and indexer affects control and stability

Because of the rigidity and precision of Motion Index Drives indexers, even a mismatch of up to 10:1 can still yield smooth, stable motion without overloading the servo or auxiliary axis motor.

However, most robot manufacturers limit movement profiles within their auxiliary axis software. Typically, the acceleration time must match the deceleration time—a constraint that can influence the final size of the indexer.

If the robot software allowed independent adjustment (prolonged acceleration and shorter deceleration), engineers could further optimize the indexer size for torque and load control.

Important Factors When Using an Auxiliary Axis Motor

When integrating a robotic auxiliary axis motor with a rotary or linear indexer, keep these points in mind:

1. Motor Compatibility:
   Motion Index Drives engineers evaluate the required torque and recommend the appropriate auxiliary axis motor based on your robot model and application parameters.

2. E-Stop and Light Screen Safety:
   A quick stop time (e.g., 100 ms) generates significantly higher forces on internal components than a 500 ms stop. Use robot safety software to adjust deceleration rates and reduce impact forces during emergency stops.

3. Movement Profiles:
   Most robot auxiliary axis software supports trapezoidal or triangular motion profiles, requiring equal acceleration and deceleration times. This limitation may necessitate a larger indexer compared to servo or AC motor systems.

4. Brake and Deceleration Settings:
   Avoid instantly applying the brake during safety stops. Program a controlled deceleration profile to prevent unnecessary strain or component wear.

5. Encoder Settings:
   When operating continuously in one direction, ensure the software can handle encoder count rollovers to maintain accurate position tracking.

6. Exact Ratio Input:
   Input the exact gear ratio into the robot controller. Don’t rely solely on the reducer ratio—include the indexer’s internal reduction for precise synchronization.

7. Validation and Commissioning:
   Always have a Motion Index Drives technician validate the auxiliary axis system during installation—on-site or via remote session—to confirm proper programming and prevent premature failures.

   🔍 This is the number-one cause of performance issues in rotary and linear indexing systems.

Optimized for Longevity

When properly sized, configured, and programmed, Motion Index Drives’ auxiliary axis indexers deliver years of flawless, maintenance-free operation.

By implementing the recommended movement profiles, ensuring accurate torque calculations, and using appropriate stop-time settings, you’ll achieve:

• ✅ Smooth, coordinated motion
• ✅ Extended component life
• ✅ Minimal vibration and mechanical wear
• ✅ Consistent, repeatable performance

📘 Learn more:

Explore Motion Index Drives Auxiliary Axis Solutions and discover how our precision rotary and linear indexers integrate seamlessly with robotic systems to enhance accuracy, productivity, and safety.