Question 49 (Textile Engineering & Fibre Science)
The vibroscope method for determination of fibre fineness does NOT take into account
| (A) | Length of specimen |
| (B) | Natural frequency of specimen |
| (C) | Tension in specimen |
| (D) | Tensile strength of specimen |
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Frequently Asked Questions | FAQs
Which instrument is used to measure fibre fineness?
There are several instruments commonly used to measure fiber fineness in textiles. The choice of instrument depends on the type of fiber being tested, the accuracy and precision required, and the specific industry or application. Some of the commonly used instruments for measuring fiber fineness include:
Micrometer: A micrometer, also known as a “micronaire,” is a device used to measure the diameter of fibers. It typically consists of a microscope with a calibrated eyepiece or stage, and a movable spindle that is used to measure the diameter of the fiber. The fiber is placed on the stage, and the spindle is used to gently press against the fiber and measure its diameter, which is then used to calculate the fineness.
Airflow instruments: Airflow instruments, such as the “airflow resistance” or “airflow permeability” method, measure the resistance of airflow through a bundle of fibers to determine their fineness. These instruments measure the pressure drop or airflow rate across a fiber bundle under controlled conditions, and the fineness is calculated based on the airflow resistance or permeability of the fiber bundle.
Laser-based instruments: Laser-based instruments, such as laser micrometers or laser diffraction instruments, use lasers to measure the diameter of fibers. These instruments typically emit a laser beam that is directed onto the fiber, and the scattered light is measured to determine the diameter of the fiber. Laser-based instruments can provide highly accurate and precise measurements of fiber fineness.
Fiber length analyzers: Fiber length analyzers, such as the “fibrograph” or “stelometer,” are instruments used to measure the average length of fibers in a sample. These instruments work by separating and aligning fibers under tension, and then measuring the length of the fibers in the sample. Fiber length is related to fineness, as longer fibers tend to have smaller fineness values.
High-performance liquid chromatography (HPLC): HPLC is a chromatographic technique that can be used to measure the chemical composition of fibers, which can be related to their fineness. HPLC involves separating and analyzing the components of a fiber sample based on their chemical properties, such as molecular weight or chemical structure.
These are some of the commonly used instruments for measuring fiber fineness in textiles. It’s important to note that the choice of instrument may depend on various factors, including the specific fiber type, the required accuracy and precision, the availability of equipment, and the specific requirements of the industry or application.
What is gravimetric method for fibre fineness?
The gravimetric method for fiber fineness determination in textiles is a technique that involves measuring the weight of a known length or mass of fiber, and then calculating the fineness based on the weight-to-length or weight-to-mass ratio.
One common gravimetric method for fiber fineness determination is the “weight per unit length” method, which is used to determine the linear density of fibers. It involves measuring the weight of a known length of fiber, typically expressed in tex, denier, or decitex. Tex is the weight in grams of 1,000 meters of fiber, denier is the weight in grams of 9,000 meters of fiber, and decitex is the weight in grams of 10,000 meters of fiber.
The gravimetric method for fiber fineness determination typically involves the following steps:
Cutting a known length of fiber specimen or taking a known mass of fiber sample.
Weighing the specimen or sample using a sensitive balance.
Calculating the fineness by dividing the weight by the length or mass, depending on the desired unit (tex, denier, decitex, etc.).
This method is commonly used for determining the fineness of natural fibers such as cotton, wool, silk, and synthetic fibers such as polyester, nylon, and acrylic. It is an important parameter in assessing the quality and performance of textile materials, as fiber fineness affects properties such as strength, appearance, and handle of the finished textile products.
It’s worth noting that there are other methods for determining fiber fineness in textiles, such as the airflow method, which measures the resistance of airflow through a fiber bundle, or microscopy-based methods that involve measuring the diameter of fibers using a microscope. The choice of method may depend on the type of fiber being tested, the accuracy and precision required, and the specific industry or application.