Controlled-Fracture Machining for Complex Shapes

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Solution Overview

Problem

Existing machining techniques are limited in precisely and rapidly machining complex and extreme shapes, particularly in mass production, mass customization, and make-to-order manufacturing environments, especially when dealing with ductile and brittle materials.

Innovation Solution

The implementation of a controlled-fracture machining process that utilizes a combination of rotary and non-rotary mechanisms to exceed a material's yield strength and breaking strength simultaneously, avoiding plastic deformation and associated issues like expansive heating and strain-hardening, allowing for precise and rapid material removal with axially asymmetrical cutting tools and programmable controllers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional deformation machining processes are used, then material can be removed from workpieces, but the machining of complex and extreme shapes is not precise and rapid enough

Engineering Contradiction:

Improvemachining precisionVSAvoidmachining speed

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The invention changes the fundamental parameter of material removal mechanism from plastic deformation to controlled fracture. By applying forces that exceed the material's breaking strength rather than yield strength, the process achieves rapid material removal through fracture rather than gradual deformation, thereby increasing productivity while maintaining precision through controlled fracture paths

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces the traditional mechanical deformation-based cutting system with a controlled fracture system. Instead of using cutting tools that plastically deform and remove material through shear, the system applies localized forces to induce controlled fracture, substituting the mechanical cutting mechanism with a fracture-based material removal approach

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If plastic deformation is used to remove material, then material can be machined, but expansive heating and strain-hardening occur

Engineering Contradiction:

Improvematerial removal capabilityVSAvoidexpansive heating and strain-hardening

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The invention converts the harmful effects of plastic deformation into beneficial outcomes by completely avoiding the deformation process. Instead of trying to manage or mitigate heating and strain-hardening, the process uses controlled fracture which inherently avoids these harmful byproducts, as fracture occurs through bond breaking rather than plastic flow that generates heat and work hardening

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Force

If rotary cutting mechanisms are used, then material removal force is sufficient, but complex and extreme shapes cannot be precisely machined

Engineering Contradiction:

Improvecutting forceVSAvoidshape precision

Core Design Contradiction:

ForceVSManufacturing precision

Solution Approach 1:

The invention segments the material removal process into controlled fracture events rather than continuous deformation. By applying localized forces that create discrete fracture zones, the process can precisely define complex shapes through controlled crack propagation paths, allowing both sufficient force application and high shape precision

Inventive Principle:

Principle #1Segmentation

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 enables the machining of complex and extreme shapes with increased productivity, precision, and applicability, including materials like carbon fiber composites that are difficult or impossible to machine with existing methods, by achieving a volumetric material removal rate two orders of magnitude greater than traditional methods and providing a smoother surface finish.

Implementation Method 1

a controlled-fracture machining process that utilizes a combination of rotary and non-rotary mechanisms to exceed a material's yield strength and breaking strength simultaneously, avoiding plastic deformation

Methodology Applied

Scientific EffectFracture Mechanics: Fracture Mechanics

Implementation Method 2

applying a predetermined force to the workpiece material... exceed a material's yield strength and breaking strength simultaneously

Methodology Applied

Scientific EffectStress:

Data Source

PatentUS8821086B2Method and apparatus for controlled-fracture machining

Publication Date: 2014.09.02 TENNINE CORP

AI summary

An apparatus (100) and method (200) of contact machining having applications in profiling operations utilizes at least one static cutting tool (101) and turret (102) driven by rotary motion (103) about a support mechanism (109) for providing sufficient force to achieve deformation by controlled fracturing (523). This allows the separation of material from a workpiece (105) without imposing axial symmetry upon either the cutting tool (101) or the workpiece (105). The apparatus and method mitigates and/or eliminates the adverse effects of plastic deformation (504) while machining a wider range of shapes and materials with greater productivity and precision than existing methods of machining.