Aircraft Skin Planing Apparatus with Orientation Contact Rollers

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Solution Overview

Problem

Existing methods for removing excess low-observable performance filler paste from fastener holes in composite aircraft skin panels are time-consuming and risk damaging the composite skin surface.

Innovation Solution

A contoured surface planing apparatus with a rotary cutter and adjustable rollers that maintain orientation contact points with the surface, allowing precise control over cutter displacement to avoid damaging the surface while removing excess material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If manual hand tools (random orbital sanders, rough file, razor blades) are used to remove excess LO filler, then the excess material can be removed, but the process becomes very time-consuming and exhausting

Engineering Contradiction:

Improvematerial removal efficiencyVSAvoidtime required for manual removal

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent replaces manual hand tools with an automated rotary cutter system that mechanically removes excess LO filler. The cutter rotates at controlled speeds and automatically traverses the surface, substituting manual mechanical action with automated mechanical action to dramatically improve productivity and reduce time requirements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The apparatus is designed to be self-guiding through the use of follow rollers that contact the contoured surface and automatically position the cutter. The system serves itself by using the workpiece geometry to guide the cutting action, eliminating the need for manual positioning and operation while maintaining high productivity.

Inventive Principle:

Principle #25Self-service

2Productivity

If manual hand tools are used without caution or skill, then material removal can proceed faster, but damage to the composite skin surface surrounding the fasteners occurs

Engineering Contradiction:

Improvematerial removal speedVSAvoiddamage to composite skin surface

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces follow rollers as intermediary elements between the cutter and the contoured surface. These rollers contact the surface first, sense its geometry, and guide the cutter's position and depth. This intermediary mechanism prevents direct contact between the cutter and the skin surface in areas where material should not be removed, eliminating surface damage while maintaining productivity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system incorporates feedback through the follow rollers that continuously contact the contoured surface and automatically adjust the cutter's position and depth based on surface geometry. This real-time feedback mechanism ensures the cutter only removes excess LO filler and stops precisely at the skin surface boundary, preventing damage even at high removal speeds.

Inventive Principle:

Principle #23Feedback

3Manufacturing precision

If the cutter is positioned close to the surface for precise material removal, then removal accuracy improves, but the risk of damaging the composite skin surface increases

Engineering Contradiction:

Improveflushness of remaining fillerVSAvoidrisk of surface damage

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The cutting system is segmented into multiple independent components: lead rollers for positioning, follow rollers for surface contact and guidance, and the cutter itself. This segmentation allows the follow rollers to independently sense surface geometry and constrain the cutter's depth, enabling precise material removal at controlled depth while preventing damage through separate positioning and cutting functions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The lead rollers contact the surface before the cutter, preliminarily establishing the correct position and depth for cutting. This preliminary action of positioning ensures the cutter approaches the surface at the precise distance needed for accurate material removal without damage, achieving both precision and safety through pre-positioning.

Inventive Principle:

Principle #10Preliminary action

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

Enables efficient and safe removal of excess filler paste, ensuring the remaining filler lies nearly flush with the skin panel surface without damaging the composite material.

Implementation Method 1

a rotary cutter supported by the main body for rotation about a cutter axis and comprising an abrasive outer circumferential cutter surface

Methodology Applied

Scientific EffectAbrasion: Abrasion

Data Source

PatentEP2777851B1Aircraft skin surface planing apparatus and method

Publication Date: 2017.08.16 LOCKHEED MARTIN CORP

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AI summary

A contoured surface planing apparatus and method for removing proud-standing material (32) from a contoured surface (24) without damaging the surface. The apparatus may include a tool (12) comprising a motor-driven rotary cutter (16) supported by a main body (14) for rotation about a cutter axis (17), and orientation contact points (27) spaced around the cutter and defining an orientation contact plane (28,29) disposed parallel to the cutter axis.