Blazed Diffractive Grating Two-Stage Cutting Method

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Solution Overview

Problem

Conventional methods for manufacturing blazed diffractive gratings are inefficient due to the need for repeated shallow cutting processes, which result in long processing times and surface roughness, reducing manufacturing efficiency and increasing the likelihood of burrs on the blazed surface.

Innovation Solution

A position-controllable high-precision cutting machine with a diamond cutting tool is used to perform a two-stage cutting process, where the first stage forms the counter surface and the second stage forms the blazed surface at a separate position, minimizing stress on the previously formed surface and reducing burrs and surface roughness, allowing for efficient formation of a large number of grooves with high precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a shallow cutting process is performed many times to form one groove, then the flatness of the blazed surface is improved and burrs are suppressed, but the manufacturing time is excessively long

Engineering Contradiction:
Improveflatness of blazed surfaceVSAvoidmanufacturing efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The cutting process is divided into two distinct stages: a rough cutting stage that removes the majority of material to form the groove, and a finishing stage that performs minimal cuts to achieve the required surface flatness and remove burrs. This segmentation allows each stage to be optimized independently, with the rough stage maximizing material removal efficiency and the finishing stage ensuring surface quality, thereby resolving the contradiction between manufacturing precision and productivity.

Inventive Principle:
Principle #1Segmentation

2Productivity

If a large cutting volume is used in one cutting process, then the manufacturing time is reduced, but burrs and surface roughness occur on the blazed surface

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidsurface roughness of blazed surface
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The rough cutting stage performs preliminary material removal to create the groove structure with minimal regard for surface quality, accepting that this stage will produce burrs and roughness. The finishing stage then applies preliminary action in reverse by carefully removing only the problematic surface layers and burrs formed in the rough stage, achieving the required surface precision without repeating the entire cutting process.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If repeatedly shallow cutting processes are performed to form one groove, then surface quality is improved, but the processing time for tens of thousands of grooves becomes too long

Engineering Contradiction:
Improvesurface quality of blazed surfaceVSAvoidprocessing time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The rough cutting stage continuously removes material in large volumes to efficiently form the groove structure, maintaining high material removal rates throughout. The finishing stage then continuously performs light passes to refine the surface, ensuring that the useful action of surface refinement continues without interruption. This continuous two-stage approach eliminates the need for repeated shallow cuts at the same location, significantly reducing total processing time while maintaining surface quality.

Inventive Principle:
Principle #20Continuity of useful action

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 method significantly reduces processing time and surface roughness, enabling the efficient manufacture of blazed diffractive gratings with a high-precision blazed surface, improving manufacturing efficiency and maintaining the flatness of the blazed surface compared to conventional techniques.

Implementation Method 1

a cutting tool (12) having a first cutting blade and a second cutting blade

Methodology Applied
Scientific EffectAbrasion: Abrasion

Data Source

PatentEP2466347B1Method of manufacturing blazed diffractive grating and method of manufacturing mold for manufacturing blazed diffractive grating
Publication Date: 2017.07.12 CANON KK
  • EP2466347B1 patent drawingFigure 1~2
  • EP2466347B1 patent drawingFigure 3~5
  • EP2466347B1 patent drawingFigure 6A~6D

AI summary

A method of manufacturing a blazed diffractive grating includes a first step of forming a first groove having a first surface (2b) and a second surface (3b) by moving, in the first direction at a first position in the second direction, a cutting tool (12) having a first cutting blade and a second cutting blade to cut the object (13); a second step of forming a second groove by moving, in the first direction at a second position separated from the first position in the second direction by a grating pitch, the cutting tool to cut the object; and a third step of forming a blazed surface (2'b) of the first groove using the first cutting blade by moving, in the first direction at a third position between the first position and the second position, the cutting tool to cut the first surface of the first groove.