Metal Matrix Composite Machining via Anodic Layer Removal

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Solution Overview

Problem

Metal matrix composite materials are difficult to machine accurately, especially those with anodizable matrix materials like aluminum, due to their hardness, which hinders their use in applications requiring precise dimensions and tight tolerances.

Innovation Solution

A method involving anodizing the anodizable matrix material to form an anodic layer, machining this layer, and repeatedly removing material through etching, abrasive blasting, or chemical stripping to expose intact abrasive particles, ensuring the article meets predetermined tolerances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional machining methods are used on metal matrix composite materials, then the material hardness provides wear resistance, but the materials are extremely hard to machine by conventional methods resulting in inability to maintain precise dimensions or tight tolerances

Engineering Contradiction:
Improvedimensional precisionVSAvoidmachinability
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

An anodic oxide layer is formed on the metal matrix composite material surface before machining operations. This preliminary treatment modifies the surface properties to reduce hardness and improve machinability, enabling subsequent precision machining to achieve tight tolerances that would be impossible on the untreated hard composite material

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The physical and chemical parameters of the material surface are changed through anodizing, which creates an oxide layer with different mechanical properties than the base composite. This parameter change transforms the surface from extremely hard and difficult to machine to a state that allows precise dimensional control while maintaining the underlying material's wear resistance

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If lasers or water jets are used to machine the blank or workpiece, then conventional machining difficulty is addressed, but precise dimensions or tight tolerances cannot be maintained

Engineering Contradiction:
Improvedimensional precisionVSAvoidmachining capability
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The anodic oxide layer is formed as a preliminary step before final precision machining. This layer acts as a protective and preparatory medium that enables conventional machining tools to achieve precise dimensions, thereby improving both machining capability and dimensional accuracy compared to direct laser or water jet machining

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The anodic oxide layer serves as an intermediary between the hard composite material and the machining tool. It mediates the interaction by providing a softer, more machinable surface layer that allows conventional tools to cut precisely, while the underlying composite material maintains its inherent hardness and wear resistance

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If abrasive particles are gradually worn and/or lost from the exposed cutting surface, then cutting ability is maintained through material removal, but tool wear results in loss of cutting ability requiring dressing of the tool

Engineering Contradiction:
Improvecutting abilityVSAvoidtool dressing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The cutting tool incorporates a mechanism for periodic exposure of fresh abrasive particles. As the tool operates and particles wear, the system periodically advances or dresses the tool surface to expose new intact particles, maintaining cutting ability through cyclic renewal rather than continuous wear

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

Worn abrasive particles are discarded from the cutting surface, and intact particles from the interior of the tool are exposed or recovered to replace them. This process maintains the tool's cutting ability by continuously renewing the active cutting surface with fresh abrasive particles

Inventive Principle:
Principle #34Discarding and recovering

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 precise machining and formation of metal matrix composite articles, allowing them to be used in high-precision applications by facilitating the removal of material and exposing new abrasive particles, thus maintaining tool effectiveness.

Implementation Method 1

anodizing the anodizable matrix material to form an anodic layer on the anodizable matrix material

Methodology Applied
Scientific EffectAnodizing: Anodising

Implementation Method 2

removing at least a portion of the anodic layer after machining by etching, abrasive blasting or chemical stripping

Methodology Applied
Scientific EffectEtching:

Implementation Method 3

During the machining process, abrasive particles are gradually worn and/or lost from the exposed cutting surface

Methodology Applied
Scientific EffectWear: Wear

Data Source

PatentEP3322842B1Forming an article made of metal matrix composite
Publication Date: 2021.04.21 RAYTHEON CANADA LTD
  • EP3322842B1 patent drawingFigure 1~2
  • EP3322842B1 patent drawingFigure 3A~3C
  • EP3322842B1 patent drawingFigure 3D~3E

AI summary

A method is disclosed for forming an article made of a metal matrix composite material having particles bonded to an anodizable matrix material. The method can include anodizing the anodizable matrix material to form an anodic layer on the anodizable matrix material. The method can also include machining at least a portion of the anodic layer.