Milling Cutter Edge Geometry for Grinding-Like Surface Accuracy

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Solution Overview

Problem

Conventional milling methods for spherical graphite cast iron result in short tool life and high damage risk due to high cutting speeds, leading to increased machining costs and defective products, as they struggle to achieve surface accuracy equivalent to grinding without excessive load on the milling cutter.

Innovation Solution

A milling cutter design with a major cutting edge positioned outside the minor cutting edge in the radial direction, where the minor cutting edge has a cutting edge angle of 0.025 to 0.11 degrees and a length of 2 to 4 mm, allowing for plastic flow to fill recesses without increasing cutting speed, thereby achieving high surface accuracy without excessive load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If high cutting speed (600 m/min or more) is used to achieve surface accuracy equivalent to grinding, then surface accuracy is improved, but tool life is extremely short and tool damage risk increases

Engineering Contradiction:
Improvesurface accuracyVSAvoidtool life
Core Design Contradiction:
Manufacturing precisionVSDuration of action of moving object

Solution Approach 1:

The cutting edge is divided into a major cutting edge and a minor cutting edge. The major cutting edge performs the primary cutting operation, while the minor cutting edge performs a secondary finishing operation to fill recesses and improve surface accuracy. This segmentation allows the tool to achieve high surface accuracy without requiring excessively high cutting speeds that would shorten tool life.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the cutting edge are given different functions and geometries. The major cutting edge has a standard geometry for efficient material removal, while the minor cutting edge has a specific geometry (cutting edge angle of 0.025 to 0.11 degrees) optimized for filling recesses and creating a polished surface effect. This local differentiation allows each portion to optimize its specific function without compromising overall tool performance.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If high cutting speed is used to prevent graphite recesses and achieve polished surface, then surface accuracy is improved, but machining cost increases due to frequent tool replacement

Engineering Contradiction:
Improvesurface accuracyVSAvoidmachining cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The cutting edge is divided into a major cutting edge and a minor cutting edge. The major cutting edge performs the primary cutting operation, while the minor cutting edge performs a secondary finishing operation to fill recesses and improve surface accuracy. This segmentation allows the tool to achieve high surface accuracy without requiring excessively high cutting speeds that would shorten tool life.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the cutting edge are given different functions and geometries. The major cutting edge has a standard geometry for efficient material removal, while the minor cutting edge has a specific geometry (cutting edge angle of 0.025 to 0.11 degrees) optimized for filling recesses and creating a polished surface effect. This local differentiation allows each portion to optimize its specific function without compromising overall tool performance.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If high cutting speed is used to achieve high surface accuracy, then surface accuracy is improved, but the possibility of tool damage increases

Engineering Contradiction:
Improvesurface accuracyVSAvoidtool damage risk
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The cutting edge is divided into a major cutting edge and a minor cutting edge. The major cutting edge performs the primary cutting operation, while the minor cutting edge performs a secondary finishing operation to fill recesses and improve surface accuracy. This segmentation allows the tool to achieve high surface accuracy without requiring excessively high cutting speeds that would shorten tool life.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the cutting edge are given different functions and geometries. The major cutting edge has a standard geometry for efficient material removal, while the minor cutting edge has a specific geometry (cutting edge angle of 0.025 to 0.11 degrees) optimized for filling recesses and creating a polished surface effect. This local differentiation allows each portion to optimize its specific function without compromising overall tool performance.

Inventive Principle:
Principle #3Local quality

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

The milling cutter achieves surface accuracy equivalent to grinding at normal cutting speeds, extending tool life, reducing machining costs, and minimizing the risk of tool damage, while efficiently planarizing machined surfaces prone to graphite recesses.

Implementation Method 1

plastic flow occurs in a surface layer of the matrix structure of the spherical graphite cast iron, and the graphite is covered with a layer of the matrix structure plastic flow

Methodology Applied
Scientific EffectPlastic flow: Plasticity

Data Source

PatentEP3034216B1Milling cutter and machining method using the same
Publication Date: 2021.09.01 DMG MORI CO LTD
  • EP3034216B1 patent drawingFigure 1~2
  • EP3034216B1 patent drawingFigure 3~4
  • EP3034216B1 patent drawingFigure 5~6

AI summary

A milling cutter with which a high degree of machined surface accuracy equivalent to that obtained by grinding is obtained without applying excessive load to the milling cutter and a machining method using the milling cutter are provided. A milling cutter is composed of a tool body having an approximately cylindrical or disk-like shape and a plurality of edge portions 10 provided on at least an outer peripheral portion of one end of the tool body at predetermined intervals along a circumferential direction. The edge portion 10 has a major cutting edge 11 and a minor cutting edge 12 that perform an operation of cutting a workpiece, the major cutting edge 11 is positioned outside the minor cutting edge 12 in a radial direction, and the minor cutting edge 12 has a cutting edge angle θb that is an angle with respect to a plane orthogonal to a center axis of the tool body and set so as to be an elevation angle open outward in the radial direction. When surface machining is performed on a workpiece with the milling cutter, a high degree of machined surface accuracy equivalent to that obtained by grinding is obtained.