CFRP End Surface Finishing to Suppress Burrs After Cutting

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Solution Overview

Problem

Carbon fiber reinforced resin shaped products face challenges in achieving smooth cutting surfaces due to burr generation and separation issues when cut using end mills, particularly when carbon fibers are aligned in one direction or randomly oriented, leading to poor surface quality and reduced productivity.

Innovation Solution

A carbon fiber reinforced resin processed product with an end surface having carbon fibers aligned in one direction or randomly oriented in a two-dimensional direction, featuring a surface roughness (Rz) within a range of greater than 5 µm to 50 µm, which suppresses burr generation and enhances surface smoothness, allowing for efficient cutting without additional polishing steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If mechanical cutting is performed on carbon fiber reinforced resin shaped products, then the product can be processed into desired size and shape, but cutting tools are quickly abraded and life expectancy becomes short

Engineering Contradiction:
Improveprocessing capabilityVSAvoidcutting tool life
Core Design Contradiction:
Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The patent replaces mechanical cutting methods with laser processing to cut carbon fiber reinforced resin shaped products. This substitution eliminates direct mechanical contact between cutting tools and the composite material, preventing tool abrasion and extending processing tool life while maintaining the ability to process products into desired sizes and shapes.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If mechanical cutting is performed on carbon fiber reinforced resin shaped products, then the product can be processed, but carbon fibers remain on cut surface in a fluffy state and cracks or separation occur

Engineering Contradiction:
Improveprocessing capabilityVSAvoidcut surface quality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent uses laser processing instead of mechanical cutting to avoid the generation of fluffy carbon fibers and surface cracks. The laser energy vaporizes and melts the material cleanly, producing a smooth cut surface without the mechanical disruption that causes fiber fluffing and delamination.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The laser processing method utilizes phase transitions (vaporization and melting) of the carbon fiber reinforced resin material to achieve clean cutting. The laser energy causes the material to transition from solid to liquid and gas phases, eliminating the mechanical stress that would otherwise cause fiber disruption and surface defects.

Inventive Principle:
Principle #36Phase transitions

3Ease of operation

If laser cutting is used on carbon fiber reinforced resin, then non-contact processing is achieved, but cutting portion and surroundings melt due to heat and layers separate

Engineering Contradiction:
Improvenon-contact processingVSAvoidprocessing precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent employs dynamic control of laser processing parameters including pulse duration, power density, and scanning speed to minimize heat accumulation. By using short pulses and rapid scanning, the laser delivers energy faster than heat can diffuse, preventing excessive melting and layer separation while maintaining non-contact processing advantages.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent utilizes periodic pulsed laser processing instead of continuous laser application. The pulsed delivery allows brief intervals for heat dissipation between pulses, preventing excessive thermal accumulation that would cause melting and delamination, while still achieving effective cutting through repeated thermal cycles.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3135716B1Machined carbon-fiber-reinforced resin product having end face and production method therefor
Publication Date: 2022.05.04 TEIJIN LTD
  • EP3135716B1 patent drawingFigure 1A~2B
  • EP3135716B1 patent drawingFigure 3~4C
  • EP3135716B1 patent drawingFigure 5~7B

AI summary

The present invention is aimed to provide a carbon fiber reinforced resin processed product which is almost free from the problems described above on a processed surface subjected to cutting or the like and has an end surface where generation of a burr is suppressed, has favorable surface properties, and surface nature, and particularly smoothness is excellent; and provides a carbon fiber reinforced resin processed product having an end surface which has fibers and a resin, wherein the end surface has a surface roughness (Rz) within a range from 5 µm to 50 µm.