Composite Workpiece Holders for As-Built Shape Machining

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Solution Overview

Problem

Composite parts, particularly large composite parts, tend to deform after being removed from the curing tool, leading to inaccuracies in machining operations and requiring post-machining adjustments, which limits determinant assembly and predictive assembly.

Innovation Solution

A system and method for handling composite workpieces that includes a workpiece holder with clamps and numerical control contacts to maintain and conform the workpiece to its as-built shape, using digital models for indexing and updating the workpiece's shape during processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If composite parts are removed from the curing tool, then the composite parts can be accessed for machining operations, but the composite parts deform leading to shape inconsistency

Engineering Contradiction:
Improveaccessibility for machiningVSAvoidshape consistency
Core Design Contradiction:
Ease of operationVSShape

Solution Approach 1:

The patent introduces a fixture system as an intermediary between the curing tool and the machining operation. This fixture includes a support surface that receives the composite part and multiple formers that apply force to maintain the part's shape, thereby preventing deformation when the part is removed from the curing tool.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies preliminary action by pre-positioning the composite part on the support surface and applying shaping forces through the formers before any machining operations begin. This ensures the part maintains its as-built shape throughout the machining process.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If post-machining operations such as shimming and additional drilling are performed, then machining accuracy can be improved, but the processing time and complexity increase

Engineering Contradiction:
Improvemachining accuracyVSAvoidprocessing speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent performs preliminary action by maintaining the composite part's shape through the fixture system with support surface and formers during the entire machining process. This prevents deformation that would otherwise require corrective post-machining operations, thereby improving productivity without sacrificing precision.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If the composite part is held in a fixed position during machining, then machining accuracy improves, but the ability to accommodate shape variations decreases

Engineering Contradiction:
Improvemachining accuracyVSAvoidaccommodation of shape variations
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by making the formers movable rather than fixed. The formers can be adjusted to apply shaping forces that accommodate variations in the composite part's shape while still maintaining the part in a consistent position for accurate machining operations.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4177169B1System and method for handling a composite workpiece in a work cell
Publication Date: 2025.08.20 THE BOEING CO
  • EP4177169B1 patent drawingFigure 1
  • EP4177169B1 patent drawingFigure 2
  • EP4177169B1 patent drawingFigure 3

AI summary

A system for handling a composite workpiece includes a work cell and a plurality of workpiece holders (106) to hold a composite workpiece in the work cell. Each one of the plurality of workpiece holders (106) is selectively controlled to index the composite workpiece in the work cell and to conform the composite workpiece to an as-built shape of the composite workpiece.