Entry Sheet Lubrication for CFRP and Metal Drilling Wear

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Solution Overview

Problem

The existing methods for cutting fiber reinforced composite materials and metals, such as carbon fiber reinforced plastics (CFRP) and titanium alloys, face challenges with drill wear, reduced drilling lifetime, and burr formation due to high cutting resistance and frictional heat, leading to poor hole quality and increased tool costs.

Innovation Solution

A cutting method using an entry sheet with a resin sheet containing solid lubricants like graphite or molybdenum disulfide, combined with cooling, to reduce cutting stress and heat accumulation, thereby extending drill lifetime and improving hole quality by minimizing burr formation and wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional drilling is used on fiber reinforced composite materials and metals, then cutting can be performed, but drill wear increases and drilling lifetime decreases due to high cutting resistance and frictional heat

Engineering Contradiction:
Improvedrilling lifetimeVSAvoiddrill wear
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

An entry sheet made of thermoplastic resin is introduced as an intermediary material between the drill and the workpiece (fiber reinforced composite material or metal). This entry sheet absorbs frictional heat and reduces cutting resistance, thereby decreasing drill wear and extending drilling lifetime while maintaining effective cutting capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The physical state and properties of the entry sheet are optimized by selecting appropriate thermoplastic resin materials and controlling processing parameters such as drilling speed and feed rate. The entry sheet's temperature and mechanical properties are dynamically adjusted during drilling to maintain optimal cutting conditions and minimize drill wear.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If conventional drilling is used on fiber reinforced composite materials, then holes can be formed, but burr formation occurs and hole quality deteriorates

Engineering Contradiction:
Improvehole qualityVSAvoidburr formation
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The entry sheet acts as a mediator that modifies the cutting interface between the drill and fiber reinforced composite material. It reduces friction and heat generation at the cutting zone, preventing fiber fraying and burr formation while ensuring clean hole edges and consistent diameter.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The entry sheet is positioned in advance at the drilling location to cushion and absorb the impact and friction forces before the drill contacts the workpiece. This pre-cushioning effect prevents excessive force transmission to the fiber reinforced composite material, thereby avoiding burr formation and maintaining hole quality.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Ease of manufacture

If high power laser and ultrashort pulse laser are used for cutting fiber reinforced plastics, then cutting can be achieved, but equipment complexity and cost increase

Engineering Contradiction:
Improvecutting capabilityVSAvoidprocessing apparatus
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

Instead of using complex high power laser systems, a simple thermoplastic resin entry sheet is introduced as a mediator to enable effective cutting of fiber reinforced plastics with conventional drilling equipment. This approach achieves comparable cutting capability while dramatically reducing equipment complexity and cost.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The entry sheet is a low-cost, disposable component made of thermoplastic resin that is consumed during the drilling process. This inexpensive consumable enables effective cutting without requiring investment in expensive laser equipment, making the process economically viable and easier to implement.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 method effectively reduces drill wear and extends drilling lifetime, enhances hole quality by maintaining uniform diameters, and decreases burr formation, improving productivity and product quality in cutting fiber reinforced composite materials and metals.

Implementation Method 1

an entry sheet which comprises a resin sheet comprising a solid lubricant selected from the group consisting of graphite, molybdenum disulfide, tungsten disulfide, molybdenum compounds, polytetrafluoroethylenes and polyimides

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 2

the cutting is performed while cooling a cutting portion and/or a cutting tool using a gas

Methodology Applied
Scientific EffectConvection cooling: Convection

Data Source

PatentEP2979832B1Cutting method
Publication Date: 2024.01.17 MITSUBISHI GAS CHEM CO INC
  • EP2979832B1 patent drawingFigure 1-1
  • EP2979832B1 patent drawingFigure 1-2
  • EP2979832B1 patent drawingFigure 1-3

AI summary

An entry sheet of the present invention is used in cutting a fiber reinforced composite material and/or a metal. Moreover, in a cutting method of the present invention, cutting of a fiber reinforced composite material and/or a metal is performed using the entry sheet.