Carbon fibre materials are lighter and stronger than iron and concrete and are used in various products in the aerospace and industrial fields as well as sports equipment. This section introduces examples of observation and measurement of carbon fibres using digital microscopes.

Observation and Measurement of Carbon Fibres Using Digital Microscopes

What is Carbon Fibre?

Carbon fibres are manufactured by burning acrylic fibres (polyacrylonitrile fibres), called the polyacrylonitrile (PAN) precursor, at high temperatures of approximately 1000°C. PAN precursors have diameters of 5 to 15 micrometres, around a tenth of a human hair. However, when compared to iron, their tensile strength is approximately 10 times higher, their density (mass per volume) is approximately one quarter, and their specific strength (strength per weight) is approximately 40 times higher. These materials provide both high levels of strength (difficult to break) as well as high levels of elastic modulus (difficult to deform).

What is CFRP?

CFRP stands for carbon fibre reinforced plastic, a type of plastic reinforced with carbon fibres.
FRPs are composite materials made by combining two or more materials. High rigidity and high strength are created by adding fibres to a base plastic as reinforcement. FRPs to which carbon fibres are added as the reinforcement are called carbon-fibre-reinforced plastics (CFRPs). These materials are characterised by conductivity, heat resistance, low thermal expansion properties, self-lubricating properties, and radiolucency in addition to high rigidity and high strength.
CFRPs have exceptional characteristics, but are more expensive than glass-fibre reinforced plastics (GFRPs).
These materials also have disadvantages. For example, they are difficult to process, easily darken, and fibre shapes remain on their surfaces.

Carbon Fibre Application Examples

Carbon fibre is used in a wide variety of industries. This section introduces some major applications.

Automobiles, motorbikes
Application: Roofs, spoilers, seat frames, wheels, muffler covers, body frames
Aerospace industry
Application: Rocket components and artificial satellites
Airline industry
Application: Aircraft bodies, helicopter blades
Application: Train bodies, bogies
Industrial machinery
Application: Robot parts, conveying equipment hands, arms, and frames
Electric appliances
Application: Housings, including PC housings and smartphone covers
Application: Frames of glasses and sunglasses, helmets
Pressure vessels
Application: Compressed natural gas (CNG) tanks, hydrogen tanks, oxygen cylinders for fire fighting
Medical equipment
Application: Radiographic equipment tables, X-ray film cassettes
Social welfare, nursing care
Application: Wheelchairs, prosthetic legs, assistive suits
Sports industry
Application: Golf club shafts, tennis rackets, bicycle frames
Leisure industry
Application: Fishing rods, yachts, cruisers, skis, snowboards

Carbon Fibre Observation and Measurement Examples Using Digital Microscopes

These are the latest examples of observation and measurement of carbon fibres using KEYENCE’s VHX Series 4K Digital Microscope.

Observation of carbon fibre cross-section
VHX-E2500, 2500×, coaxial illumination
Observation of cracks on a laminated CFRP plate
ZS-200, 1000×, coaxial illumination + image stitching
A wide area can be observed at high resolution using the image stitching function.
Observation of an automobile body carbon cloth
VHX-E20, 20×, ring illumination
Optical Shadow Effect Mode image
VHX-E20, 20×, ring illumination
Optical Shadow Effect Mode + colour image
The Optical Shadow Effect Mode makes it possible to observe fine irregularities on fibre surfaces without using a scanning electron microscope (SEM).
Automatic area measurement of a golf club shaft cross-section
ZS-200, 1000×, coaxial illumination, before measurement
ZS-200, 1000×, coaxial illumination, after automatic area measurement
The golf club shaft strength and weight can be analysed by measuring the area ratio of carbon fibres using the automatic area measurement function.
Automatic area measurement of a fuel tank cross-section
VHX-E500, 2000×, coaxial illumination, before measurement
VHX-E500, 2000×, coaxial illumination, after automatic area measurement
The area ratio of carbon fibres used to be measured manually, which took a lot of time. Now, it can be measured accurately by simply using the automatic area measurement function.