Scarf Repair Guide Duplication for Precise Composite Void Milling

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Solution Overview

Problem

Conventional scarf repair techniques for fiber-reinforced polymer parts are inefficient, leading to inaccurate estimation of void size, unnecessary material waste, and reduced structural integrity due to manual processes and lack of precision.

Innovation Solution

A duplicator assembly and system that uses a probe and milling tool to accurately form a void in a laminated material by tracing a scarf repair guide, with a scanning tool generating data for precise void creation and an articulatable arm allowing movement about multiple axes for precise alignment and removal of material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional manual scarf repair techniques are used, then the repair process can be performed with simple equipment, but the accuracy of void size estimation deteriorates leading to material waste and reduced structural integrity

Engineering Contradiction:
Improvevoid size estimation accuracyVSAvoidlaminated material waste
Core Design Contradiction:
Measurement precisionVSLoss of substance

Solution Approach 1:

The patent uses a duplicator assembly that traces the contour of the abnormality to create a duplicate void shape. The probe traces the abnormality boundary while the milling tool simultaneously removes material, copying the exact shape and size of the abnormality without manual estimation, thereby eliminating material waste while maintaining precise void formation

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The duplicator assembly provides real-time feedback by using the probe to continuously trace the abnormality contour during the void formation process. The system adjusts the milling tool's path based on the probe's position, ensuring the void exactly matches the abnormality shape and size, thus preventing both material waste and insufficient removal

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If manual scarfing plies is performed, then the process can be completed with basic tools, but variation is introduced that negatively affects the appearance of the repair

Engineering Contradiction:
Improvevoid shape consistencyVSAvoidoperation complexity
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The duplicator assembly is self-guiding, where the probe automatically traces the abnormality contour and the milling tool automatically follows the traced path. The system performs its own guidance function without requiring manual intervention for positioning, ensuring consistent void shape while simplifying the operator's role to merely initiating and monitoring the process

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent combines the tracing function (probe) and material removal function (milling tool) into a single integrated duplicator assembly. Both functions operate simultaneously and are mechanically linked through the arm, ensuring that the void formation automatically follows the abnormality contour with high precision and consistency

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If conventional void forming techniques are used, then the equipment required is simple, but the time required for repair increases due to manual processes

Engineering Contradiction:
Improverepair process efficiencyVSAvoidmanual scarfing time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The duplicator assembly performs continuous material removal as the probe traces the abnormality contour. The milling tool operates continuously along the traced path without interruption or repeated positioning, eliminating the time-consuming manual scarfing steps while maintaining high productivity through uninterrupted material removal

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP3885114B1Scarf repair apparatus, system, and method
Publication Date: 2024.01.17 THE BOEING CO
  • EP3885114B1 patent drawingFigure 1
  • EP3885114B1 patent drawingFigure 2
  • EP3885114B1 patent drawingFigure 3

AI summary

Disclosed herein is a duplicator assembly (122) for forming a first void (144), which can be layered, in a laminated material of a part (102) that matches a second void (142) in a scarf repair guide (120). The duplicator assembly (122) comprises an arm (134) that comprises a first end portion (146) and a second end portion (148). The first end portion (146) is spaced apart from the second end portion (148). The duplication assembly (122) also comprises a probe (136) that is fixed to the first end portion (146) of the arm (134) and configured to trace the second void (142) in the scarf repair guide (120). The duplication assembly (122) further comprises a milling tool (140) that is fixed to the second end portion (148) of the arm (134) such that the milling tool (140) is co-movably coupled with the probe (136) via the arm (134).