Conditioned End Mill Relief Geometry for Stable Aluminum Milling

Solution Overview

Problem

Milling of non-ferrous materials like aluminum often results in chatter due to sharp cutting edges and high spindle speeds, leading to poor surface finish, reduced tool life, and potential spindle bearing damage.

Innovation Solution

A rotary cutting tool with a solid end mill design featuring an inner eccentric relief with a relief angle of less than 5 degrees and an outer eccentric relief with a relief angle between 5 and 15 degrees, which reduces chatter and improves cutting performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If sharp cutting edges are used for machining non-ferrous materials, then cutting performance and surface finish are improved, but chatter increases leading to reduced tool life and potential spindle bearing damage

Engineering Contradiction:

Improvesurface finishVSAvoidtool life

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies local quality by creating two distinct relief zones with different angles on the cutting edge. The first relief portion has a smaller relief angle (0-5 degrees) for reduced chatter, while the second relief portion has a larger relief angle (5-15 degrees) for sharp cutting performance. This localized differentiation allows each zone to perform its specific function optimally.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The cutting edge relief surface is segmented into two distinct portions along the cutting edge. The first relief portion and second relief portion are separated and have different geometric characteristics, allowing independent optimization of each zone for its specific function in reducing chatter versus maintaining sharpness.

Inventive Principle:

Principle #1Segmentation

2Productivity

If high spindle rotational speeds are used for slot-milling operations, then productivity is improved, but chatter increases causing vibration and potential spindle bearing damage

Engineering Contradiction:

Improvemachining speedVSAvoidchatter vibration

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating two distinct relief zones with different angles on the cutting edge. The first relief portion has a smaller relief angle (0-5 degrees) for reduced chatter, while the second relief portion has a larger relief angle (5-15 degrees) for sharp cutting performance. This localized differentiation allows each zone to perform its specific function optimally.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent addresses mechanical vibration by designing a relief configuration that reduces chatter through specific geometric parameters. The small relief angle portion (0-5 degrees) is specifically engineered to dampen vibrations and reduce chatter during high-speed slot-milling operations.

Inventive Principle:

Principle #18Mechanical vibration

3Force

If larger relief angles are used on the relief surface, then sliding friction is reduced, but the cutting edge becomes less sharp increasing chip thickness

Engineering Contradiction:

Improvecutting forcesVSAvoidchip thickness control

Core Design Contradiction:

ForceVSManufacturing precision

Solution Approach 1:

The patent applies local quality by creating two distinct relief zones with different angles on the cutting edge. The first relief portion has a smaller relief angle (0-5 degrees) for reduced chatter, while the second relief portion has a larger relief angle (5-15 degrees) for sharp cutting performance. This localized differentiation allows each zone to perform its specific function optimally.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The cutting edge relief surface is segmented into two distinct portions along the cutting edge. The first relief portion and second relief portion are separated and have different geometric characteristics, allowing independent optimization of each zone for its specific function in reducing chatter versus maintaining sharpness.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentEP4552775A1End mill with conditioned cutting edge and method of making same

Publication Date: 2025.05.14 KENNAMETAL INC

Figure 1
Figure 2~3
Figure 4

AI summary

A rotary cutting tool (10) includes a shank portion (12) and a cutting portion (14) extending from the shank portion (12) to a cutting tip (16). The cutting portion (14) has a plurality of blades (18) separated by flutes (20). Each of the blades (18) includes a relief surface (22) and a radial cutting edge (24) formed at an intersection between a respective flute (20) and the relief surface (22). The relief surface (22) includes an inner eccentric relief (30) immediately adjacent the radial cutting edge (24) and an outer eccentric relief (32) immediately adjacent the inner eccentric relief (30). The inner eccentric relief (30) is formed with an inner eccentric relief angle, β, of less than about 5 degrees, and wherein the outer eccentric relief (32) is formed with an outer eccentric relief angle, β, of between about 5 degrees and about 15 degrees. A method of making the rotary cutting tool (10) is also described.