EasternGear's Globoid Worm Gear for Rotary Indexers

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Today, we delve into the use of EasternGear reducers in positioners and their pivotal role in achieving precise positioning.

What is a Positioner?

A positioner is a precision device essential in automated production lines, known for its ability to handle heavy loads while providing accurate positioning. Unlike high-speed rotational devices, positioners are used for controlled, multi-directional movements to set the position and angle of objects precisely. 

Commonly used in conjunction with welding robots, positioners are crucial in industries like automotive manufacturing. Here, the workbench that holds the vehicle frame is the positioner, and it moves the frame to the desired angles for robotic welding operations. The gif below shows two robots-- the larger one being holding the frame, and the smaller being the welding robot. Both are utilizing positioners at the base of the robot (circled). 

https://www.youtube.com/watch?v=DFMRwK0YkPs

For a detailed overview of how positioners and rotary indexers work, refer back to the previous blog post, "Rotary Indexers, Positioners, and the Unsung Hero: The Role of Globoid Worm Gears in Precision Manufacturing".

The Role of Worm Gear Reducers

To achieve the precision required for these tasks, positioners rely on worm gear reducers. These reducers offer a high reduction ratio, ideal for applications requiring low speed and high torque. The worm gear provides the primary reduction and torque, while the roller cam handles final positioning and fine adjustments. This combination ensures that heavy loads are moved with precision and smoothness.

In Part 1, we explored the general benefits of globoid worm gears, which are key components in positioners and rotary indexers.

Precision Testing of EasternGear Reducers

To ensure the highest performance in positioners, the precision of the reducers was rigorously tested. EasternGear’s worm reducers recently excelled in a repeatability test conducted by a leading company, securing a place in their positioners.

Test Details:

• Objective: Verify the positional accuracy and repeatability of reducers in positioners under heavy loads.
• Target Object Weight: 2.5 tons and 5 tons (steel plates)
• Size of Target Object: 2m x 4m rectangular shape
• Test Duration: 10 hours a day for 30 days
• Measurement Items: Reducer heating, noise levels, positional deviation
• Final Error Range Requirement: Within 0.1 mm

Testing Procedure:

1. Initial Setup: Positioners equipped with reducers from various manufacturers were set up with target objects weighing 2.5 tons and 5 tons.
2. Rotation Cycle: Each positioner was rotated 360 degrees clockwise, then stopped abruptly, reversed direction, and stopped abruptly again.
3. Repetitions: This cycle was repeated for 10 hours a day, for 30 days to test repeatability and precision.
4. Measurements: During testing, the positional accuracy was checked to ensure the positioner stopped at the same location consistently. Parameters such as heating, noise, and deviation from the initial position were monitored.

Results:

• Performance: EasternGear’s worm reducer demonstrated no excessive heating issues, no changes in output, and no positional deviation within 0.02 mm from the initial set position.
• Error Range: Achieved a final error range well within the 0.1 mm requirement, translating to an angular error of approximately 0.0006°.

Features of EasternGear Worm Reducers

Our precision worm reducers, selected for high-load spot welding applications, feature a pre-loaded barrel cam structure to prevent backlash. They operate effectively without additional guides or locking devices and include side support bearings for enhanced load resistance. Capable of handling loads from 2.5 tons to 7.5 tons, they are available in various specifications with different gear ratios to meet specific customer needs.