Robotic Coil Insert Tool With Spring Compliance Against Breakage
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Solution Overview
Problem
Superalloy coil inserts used in the aerospace industry are prone to breakage during automated insertion due to their rigidity and lack of compliance, which increases friction and stress, especially when inserted into threaded holes in large civil gas turbine engines, as robot tool operators lack the ability to respond to friction changes like human operators.
Innovation Solution
A device with a manipulator end and tool support mounted on a robot arm, featuring spring members that allow the insertion tool to twist and compensate for the lack of compliance in superalloy coil inserts, mimicking human operator adjustments and reducing friction and stress during the insertion process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a robot tool operator is used for automated insertion, then productivity is improved, but the coil insert is more likely to break due to inability to respond to friction changes
Solution Approach 1:
A compliant mechanism acts as an intermediary between the robot tool operator and the coil insert. This mechanism provides the necessary compliance and friction compensation that the rigid robot lacks, allowing automated insertion without increasing breakage rates. The compliant mechanism translates the robot's rigid motion into a controlled insertion process that can accommodate friction variations.
Solution Approach 2:
The system changes the compliance parameter of the insertion tool by incorporating elastic elements or compliant mechanisms. This allows the tool to exhibit friction-compensating behavior similar to human operators, enabling automation while maintaining low breakage rates through dynamic adjustment of insertion parameters.
2Strength
If a superalloy coil insert is used, then strength is improved, but compliance is reduced leading to increased friction and breakage risk
Solution Approach 1:
The insertion system is segmented into two functional parts: the superalloy coil insert (providing strength) and the compliant insertion tool (providing compliance). This segmentation allows each component to optimize its primary function while the compliant tool compensates for the insert's rigidity, reducing friction and breakage risk during automated insertion.
Solution Approach 2:
The compliant insertion tool serves as an intermediary that bridges the gap between the rigid robot operator and the rigid superalloy insert. It provides the necessary compliance to accommodate friction variations without requiring the insert itself to be compliant, thus maintaining the insert's strength properties while enabling safe automated insertion.
3Reliability
If friction compensation is provided, then breakage is reduced, but device complexity increases
Solution Approach 1:
The compliant mechanism is designed to automatically compensate for friction variations during insertion without requiring external sensing or control systems. The compliance is built into the mechanism's structure, allowing it to self-adjust and compensate for friction changes passively, thus reducing breakage while avoiding additional complexity from active control systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device significantly reduces coil breakages during automated insertion by providing compliance and allowing the robot arm to adjust its position, thereby minimizing cross-threading and jamming, and enabling successful automation of the insertion process in large-scale manufacturing.
Implementation Method 1
one or more spring members which extend between the tool support and the insertion tool, the one or more spring members allowing the insertion tool to twist about the insertion axis relative to the tool support in reaction to the applied torque
Data Source
AI summary
A device is provided for inserting coil inserts into threaded holes. The device includes an insertion tool having a manipulator end which is configured to receive and hold a coil insert, and which is operable to apply a torque to the coil insert to screw the coil insert into a threaded hole when presented thereto, the manipulator end having an insertion axis which is coincident with the axis of the coil insert when held by the manipulator end. The device further includes a tool support to which the insertion tool is mounted, the tool support being fixable to an end of a robot arm whereby the manipulator end is presentable by the robot arm to the threaded hole for insertion therein of the coil insert.