Half-Conical End Mill for Deep Fine Microlens Cutting

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Solution Overview

Problem

Existing end mills, such as ball end mills, face challenges in cutting deep microlenses without causing processing defects due to the center of rotation interference, and they are not suitable for cutting fine microlenses with an outer diameter of 100 µm or less.

Innovation Solution

An end mill with a cutter portion having a convex shape that is half of a conical body, allowing for a wider effective blade range of greater than 90 degrees and less than 180 degrees, enabling deeper cutting without processing defects and accommodating fine microlenses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If a ball end mill is used for deep microlens cutting, then cutting depth is improved, but processing defects occur due to center of rotation interference

Engineering Contradiction:
Improvecutting depthVSAvoidprocessing defect
Core Design Contradiction:
Length of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The invention extracts the harmful center of rotation from the processing area by tilting the rotational axis of the cutter portion. The rotational axis is inclined at an angle θ greater than 0° and less than or equal to 45° with respect to the normal direction of the processing surface, so that the center of rotation does not contact the processing surface during cutting, thereby eliminating processing defects while maintaining deep cutting capability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the orientation of the cutter portion from a conventional vertical or horizontal position to a tilted position in three-dimensional space. By inclining the rotational axis at angle θ, the effective blade range is expanded to greater than 90° and less than 180°, allowing deep cutting without center interference through spatial reconfiguration

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If the rotational axis of the cutter portion is tilted to avoid processing defects, then processing quality is improved, but cuttable depth becomes shallow

Engineering Contradiction:
Improveprocessing defectVSAvoidcuttable depth
Core Design Contradiction:
Object-affected harmful factorsVSLength of stationary object

Solution Approach 1:

The invention optimizes the tilt angle parameter θ to be greater than 0° and less than or equal to 45°. This specific parameter range allows the effective blade range to be greater than 90° and less than 180°, which simultaneously prevents center of rotation interference and maintains sufficient cuttable depth for deep microlens fabrication

Inventive Principle:
Principle #35Parameter changes

3Productivity

If a nose end mill with multiple blades is used, then cutting capability is improved, but the cutter diameter becomes large making it unsuitable for fine microlenses

Engineering Contradiction:
Improvecutting capabilityVSAvoidcutter diameter
Core Design Contradiction:
ProductivityVSArea of stationary object

Solution Approach 1:

The invention applies local quality by configuring the cutter portion with a specific convex shape that is half of a conical body. This localized geometric design allows the cutter to achieve an effective blade range greater than 90° while maintaining a small overall diameter suitable for fine microlenses with outer diameter of 100 μm or less, without requiring multiple blades

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4559604A1End mill, method for producing mold for creating microlens, and device for producing mold for creating microlens
Publication Date: 2025.05.28 DEXERIALS CORP
  • EP4559604A1 patent drawingFigure 1A~1B
  • EP4559604A1 patent drawingFigure 1C~2
  • EP4559604A1 patent drawingFigure 3~4

AI summary

An end mill is provided, which includes a cutter portion that has a convex shape having a curved surface. The convex shape is a half of a conical body obtained by dividing the conical body into two along a plane including a center line passing through a center of a bottom surface of the conical body. The conical body includes a tip portion, the bottom surface having a circular shape, and a circumferential surface including an enlarged diameter region having a diameter larger than a diameter of the bottom surface, where a tip of the tip portion is positioned on the center line passing through the center of the bottom surface.