High-Precision Hollow Harmonic Rotary Actuator for CNC Machines and Heavy-Duty Rotary Axes

When engineers design CNC machines, rotary tables, and machining equipment, one common concern is whether directly mounting a workpiece on the rotary table could cause deformation or affect positioning accuracy due to an eccentric load.

When a workpiece is mounted away from the center of the rotary axis, the system may simultaneously experience radial loads, axial loads, and overturning moments. The rotary actuator therefore needs not only sufficient torque, but also adequate load-bearing capacity and positioning accuracy.

Hello, I’m Theodore Li, Technical Director at HONPINE. Today, I will introduce the HONPINE 58 Series Harmonic Rotary Actuator, a high-precision hollow rotary actuator designed for CNC machines, precision rotary axes, and heavy-duty rotary positioning applications.

HONPINE 58 Series Harmonic Rotary Actuator: Key Specifications

The HONPINE 58 Series is a high-torque harmonic rotary actuator featuring a large hollow bore and an optional flange configuration.

Depending on the reduction ratio, the actuator provides peak torque of up to 2,722 N·m and rated torque of up to 1,494 N·m.

50 mm Hollow Bore for Cable and Tubing Routing

The 58 Series features a 50 mm hollow through bore, allowing cables, pneumatic tubing, laser beams, hydraulic lines, sensor cables, and cooling lines to pass through the rotation axis.

This hollow structure can simplify system integration and provide greater flexibility when designing compact rotary mechanisms.

Compact Installation Dimensions

The actuator has an outer diameter of 220 mm.

• Without brake: 216 mm

• With brake: 249.4 mm

• Hollow bore: 50 mm

Suitable for Large Rotary Mechanisms

The 58 Series is suitable for larger:

• CNC rotary tables

• Rotary axes

• Precision machining axes

• Heavy-duty positioning axes

Integrated Crossed Roller Bearing for Multi-Directional Loads

The output side of the 58 Series uses an integrated crossed roller bearing.

Crossed roller bearings arrange cylindrical rollers in alternating directions, allowing the bearing to support loads from multiple directions while providing high rigidity. This makes them suitable for rotary mechanisms subjected to combined radial loads, axial loads, and moment loads.

High Radial, Axial, and Moment Load Capacity

The 58 Series provides:

• Radial load: 3,200 N

• Axial load: 3,200 N

• Moment load: 2,500 N·m

This load-bearing capability makes the actuator suitable for rotary mechanisms where the workpiece or tooling is mounted away from the rotation center and generates additional radial, axial, or overturning loads.

Typical Rotary Axis Applications

• CNC Rotary Table

• CNC B-Axis

• CNC C-Axis

• Rotary Indexing Table

• Precision Rotary Platform

• Laser Processing Rotary Axis

• Inspection Rotary Axis

Multi-Turn Absolute Encoder for Precision Rotary Positioning

The 58 Series can be equipped with either a 23-bit Tamagawa protocol multi-turn absolute encoder or a 24-bit Nikon protocol multi-turn absolute encoder.

A multi-turn absolute encoder provides the controller with absolute position feedback across multiple revolutions.

In practical terms, it helps answer a fundamental question in precision motion control:

“Where is the axis right now?”

Absolute Position Feedback

Unlike incremental feedback systems that may require a homing process after power-up, an absolute encoder can provide the current position directly, depending on the system architecture and encoder configuration.

Controller and Servo System Integration

The encoder options are designed to support requirements related to:

• Controller compatibility

• Servo system integration

• CNC control system integration

• Absolute position feedback

• Precision rotary positioning

Positioning Accuracy Below 30 Arcsec

The HONPINE 58 Series provides positioning accuracy of less than 30 arcsec.

For CNC rotary tables, CNC A-axis, C-axis, and 5-axis machining centers, rotary axes may repeatedly move between positions such as:

0° → 30° → 60° → 90°

During machining and indexing operations, positioning accuracy determines how closely the rotary axis reaches the commanded angular position.

30 arcsec ≈ 0.0083°.

This level of angular positioning accuracy is suitable for precision rotary positioning applications where angular deviation needs to be tightly controlled.

Repeat Positioning Accuracy Below 5 Arcsec

In addition to positioning accuracy, the 58 Series achieves repeat positioning accuracy of less than 5 arcsec.

Repeatability describes how consistently the rotary axis can return to the same target position over repeated movements.

Applications Requiring High Repeatability

This is particularly important for:

• Repeated machining operations

• Rotary indexing

• Multi-position processing

• Precision inspection

• Repeated positioning of different workpieces

High repeat positioning accuracy helps maintain consistency across repeated machining and indexing operations.

Positioning Accuracy vs. Repeat Positioning Accuracy

For precision equipment, it is important to distinguish between positioning accuracy and repeat positioning accuracy.

A system can repeatedly return to a position with very small variation while still having a larger absolute position error. Both parameters should therefore be considered when selecting a precision rotary actuator.

Applications of the HONPINE 58 Series

The 58 Series is designed for precision rotary applications requiring a combination of high torque, hollow-axis integration, multi-directional load capacity, absolute position feedback, and high positioning repeatability.

Laser Processing Equipment

• Laser cutting

• Laser welding

• Laser marking

• Laser engraving

• Laser processing rotary axes

The 50 mm hollow bore can provide a convenient routing path for cables, tubing, optical paths, or other components through the rotary axis, depending on the system design.

Semiconductor and Optical Equipment

• Wafer inspection

• Optical inspection

• Camera positioning

• Lens alignment

• Precision measurement

• Semiconductor handling

The multi-turn absolute encoder and high repeat positioning accuracy are particularly relevant to applications requiring precise and repeatable rotary positioning.

Precision Inspection and Assembly Equipment

• Automatic indexing

• Multi-station assembly

• Precision positioning

• Rotary inspection

• Automatic calibration

For these applications, the combination of high rigidity, multi-directional load capacity, and repeat positioning accuracy can help support stable rotary positioning.

High-Torque Hollow Rotary Motion for Demanding Applications

The HONPINE 58 Series combines a 50 mm hollow bore, high torque capacity, integrated crossed roller bearing, multi-turn absolute encoder options, positioning accuracy below 30 arcsec, and repeat positioning accuracy below 5 arcsec in a compact rotary actuator architecture.

For CNC rotary tables, precision rotary axes, laser processing equipment, inspection systems, and other heavy-duty rotary mechanisms, these features provide a foundation for high-precision rotary motion and flexible mechanical integration.

Contact HONPINE to obtain more information about the 58 Series high-precision hollow harmonic rotary actuator and discuss your rotary motion requirements.