Composite Milling Cutter Geometry for Delamination Control

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Solution Overview

Problem

Milling tools face challenges when processing fiber composite materials like carbon fiber reinforced plastics, as they require clean cutting without fiber residues, minimal force application to prevent delamination, and smooth surfaces, while also needing to manage cutting forces effectively.

Innovation Solution

A milling tool design featuring peripheral cutting edges that form a closed cylinder surface, with adjustable clearance angles and helix angles, and auxiliary flutes that divide cutting units to allow for independent design of cutting wedges and forces, enabling targeted control of cutting forces and surface quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional milling tools with single-point cutting edges are used, then the tool structure is simple, but grooves are formed on the machined surface and cutting forces cannot be controlled

Engineering Contradiction:
Improvesurface qualityVSAvoidtool structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The cutting section is divided into multiple individual cutting units arranged circumferentially, each with its own cutting edge. This segmentation allows the cutting forces to be distributed and controlled, preventing groove formation while maintaining surface quality without requiring overly complex tool structures

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple cutting edges are combined to form a closed cylindrical cutting section. This merging of multiple cutting elements creates a continuous cutting action that eliminates grooves on the machined surface while distributing the cutting forces across multiple points, improving surface quality without excessive complexity

Inventive Principle:
Principle #5Merging (Combining)

2Productivity

If large clearance angles are used behind cutting edges, then chip removal is facilitated, but stable cutting wedges cannot be formed

Engineering Contradiction:
Improvechip removalVSAvoidcutting wedge stability
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

Different clearance angles are applied to different cutting units circumferentially. Some cutting units have larger clearance angles to facilitate chip removal, while others have smaller clearance angles to form stable cutting wedges. This local differentiation resolves the contradiction by allowing both chip removal and wedge stability in different locations

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The clearance angles are varied dynamically around the circumference of the cutting section rather than being uniform. This dynamic variation allows the tool to adapt to different cutting conditions at different positions, enabling both effective chip removal and stable wedge formation as needed

Inventive Principle:
Principle #15Dynamics

3Productivity

If cutting forces are increased to improve cutting efficiency, then material removal rate increases, but delamination of thin-walled components occurs

Engineering Contradiction:
Improvematerial removal rateVSAvoiddelamination
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The total cutting force is segmented and distributed across multiple individual cutting units arranged around the circumference. Each cutting unit exerts a smaller, localized force, preventing the concentrated high forces that cause delamination in thin-walled components, while the cumulative effect maintains high material removal rate

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of using a single cutting edge with full cutting force, multiple cutting edges perform partial cutting actions simultaneously. Each cutting unit removes a portion of the material, and the combined effect achieves high productivity while keeping individual cutting forces low enough to prevent delamination

Inventive Principle:
Principle #16Partial or excessive action

4Ease of manufacture

If helix angles and clearance angles are fixed, then tool manufacturing is simplified, but cutting forces and vibration cannot be optimized

Engineering Contradiction:
Improvetool fabricationVSAvoidcutting force control
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

Different helix angles and clearance angles are applied to different cutting units circumferentially rather than using uniform values throughout. This local differentiation allows optimization of cutting forces and vibration characteristics for specific applications while maintaining reasonable manufacturing complexity through modular design

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The helix angles and clearance angles are varied as parameters across different cutting units to optimize cutting performance. By changing these geometric parameters locally, the tool can be tailored to control cutting forces and reduce vibration while still being manufacturable through standardized processes

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3695928B1Milling tool for machining fibre composites
Publication Date: 2023.06.21 GUNTHER WIRTH HARTMETALLWERKZEUGE
  • EP3695928B1 patent drawingFigure 1~2
  • EP3695928B1 patent drawingFigure 3~6
  • EP3695928B1 patent drawingFigure 7~8

AI summary

A milling tool (100) for machining fiber-reinforced composite materials is provided, comprising: a clamping section (1) and a cutting section (2) extending along a longitudinal axis (Z). The cutting section (2) is designed in a cylindrical basic shape, the outer circumference of which is divided into a plurality of cutting units (3) by a plurality of intersecting first main flutes (LS) designed as left-hand spirals and second main flutes (RS) designed as right-hand spirals. Each cutting unit (3) has a first peripheral cutting edge (LR) extending along a left-hand spiral and a second peripheral cutting edge (RR) extending along a right-hand spiral. The first peripheral cutting edges (LR) and the second peripheral cutting edges (RR) are each formed along a common enveloping cylindrical surface that defines the outer circumference of the cutting section (2).The first circumferential cutting edges (LR) are each followed circumferentially by first clearance surfaces (5) extending at a first clearance angle (y), and the second circumferential cutting edges (RR) are each followed circumferentially by second clearance surfaces (6) extending at a second clearance angle (δ). A plurality of auxiliary flutes (HS) extending spirally and radially recessed relative to the first and second clearance surfaces (5; 6) are formed on the cutting section (2). These flutes divide the individual cutting units (3) into a first region (B1), where the respective first circumferential cutting edge (LR) with the first clearance surface (5) is formed, and a second region (B2), where the respective second circumferential cutting edge (RR) with the second clearance surface (6) is formed.