Dual-Head pECM Machining for Fixture-Free Airfoil Processing

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Solution Overview

Problem

Conventional pulsed electrochemical machining (pECM) systems require extensive fixturing and clamping to maintain the workpiece during processing, limiting their versatility in machining components with varying shapes and sizes, especially for complex geometries like airfoils, due to uneven pressure distribution from single tool bodies.

Innovation Solution

The use of dual tool bodies or 'dual heads' that oscillate independently or in synchronization to maintain equal pressure on opposite sides of the workpiece, reducing the need for extensive fixturing by canceling out forces and allowing for simultaneous machining of multiple surfaces, thereby accommodating workpieces of varying dimensions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If single tool body is used for pECM machining, then the structure is simple, but extensive fixturing and clamping are required to maintain workpiece stability

Engineering Contradiction:
Improvetool body structureVSAvoidworkpiece positioning flexibility
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The dual tool body configuration applies counterbalancing forces on opposite sides of the workpiece. Each tool body exerts pressure on its respective side, and the forces are designed to cancel each other out, eliminating the need for extensive external fixturing and clamping mechanisms while maintaining workpiece stability throughout the machining process.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The invention transitions from a single-point machining approach to a multi-dimensional approach by positioning tool bodies on opposite sides of the workpiece. This spatial arrangement allows simultaneous machining of multiple surfaces while the counterbalancing forces in the opposite direction eliminate the need for complex positioning fixtures.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If dual tool bodies are used to machine opposite sides simultaneously, then productivity increases, but device complexity increases

Engineering Contradiction:
Improvemachining throughputVSAvoidtool body configuration
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention combines two machining operations into a single integrated system. Dual tool bodies are mounted on a common structure and controlled by a coordinated system, allowing simultaneous machining of opposite sides of the workpiece. This merging of operations doubles productivity while the integrated control system manages the increased complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The dual tool body system enables continuous machining of both sides of the workpiece simultaneously, eliminating the need to reposition or refixture the workpiece between operations. Both tool bodies operate continuously and concurrently, maximizing productive action throughout the entire machining cycle.

Inventive Principle:
Principle #20Continuity of useful action

3Manufacturing precision

If extensive fixturing is used to maintain workpiece, then machining precision is maintained, but ease of operation decreases

Engineering Contradiction:
Improveworkpiece positioning accuracyVSAvoidsetup complexity
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The dual tool body system is designed to self-stabilize the workpiece through counterbalancing forces. The opposing tool bodies automatically maintain equilibrium and positioning accuracy without requiring external fixtures or complex clamping arrangements. The system serves its own positioning function, eliminating the need for separate fixturing components.

Inventive Principle:
Principle #25Self-service

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

This approach enhances the throughput and efficiency of pECM by minimizing the requirement for mechanical supports, allowing for the machining of complex shapes without compromising precision, and enabling the processing of components with reduced fixturing complexity.

Implementation Method 1

pulsed electrochemical machining (pECM) is a non-contact machining process based on the principles of electrolysis

Methodology Applied
Scientific EffectElectrolysis: Electrolysis

Implementation Method 2

the workpiece dissolves anodically about the tool

Methodology Applied
Scientific EffectAnodic dissolution: Oxidation

Implementation Method 3

An electrolyte pumped between the tool and the workpiece may remove dissolved metal from the workpiece and heat

Methodology Applied
Scientific EffectFluid flow: Convection

Data Source

PatentEP4269012A1Dual head pecm
Publication Date: 2023.11.01 ROLLS ROYCE CORP
  • EP4269012A1 patent drawingFigure 1A
  • EP4269012A1 patent drawingFigure 1B
  • EP4269012A1 patent drawingFigure 1C

AI summary

In some examples, a pulsed electrochemical machining (pECM) system including a first tool body including a first electrode defining a working surface at a distal end of the tool axis configured to face a workpiece and a second tool body including a second electrode defining a working surface at a distal end of the tool axis configured to face a workpiece. The system includes a mechanical system configured to position the working surface of the first tool body relative to the workpiece and configured to position the working surface of the second tool body relative to the workpiece. The system includes an electrolyte system configured to supply electrolyte to a first interelectrode gap and a second interelectrode gap and a power supply configured to generate a pulsed direct current between the first tool body and the workpiece and the second tool body and the workpiece.