Question 34 (Textile Engineering & Fibre Science)
Consider the following assertion [a] and reason [r] and choose the most appropriate answer.
[a] Cut and crush method for tow to top conversation uses cutting roller with embedded helical blade [r] This helps to impart crimp in the cut fibres
| (A) | [a] is right [r] is wrong |
| (B) | [a] is right [r] is right |
| (C) | [a] is wrong [r] is wrong |
| (D) | [a] is wrong [r] is right |
[Show Answer]
Option A
Frequently Asked Questions | FAQs
What is crush cutting?
The crush and cut method is a common technique used to impart crimp or waviness in fibers. It involves mechanically deforming or manipulating the fibers to create a crimped or wavy structure, which can provide enhanced bulkiness, resilience, and insulation properties to the fibers. The crush and cut method is typically used for thermoplastic fibers, such as polyester and nylon, which can be easily softened and reshaped with heat.
The basic steps involved in the crush and cut method are as follows:
Crushing: The fibers are first subjected to a mechanical crushing process, which involves compressing the fibers between two rollers or plates with a patterned surface. The pressure applied during the crushing process causes the fibers to deform and take on the shape of the pattern on the rollers or plates, creating a temporary crimp or wave structure in the fibers.
Cutting: After the crushing process, the fibers are cut into shorter lengths. This can be done by passing the crushed fibers through a cutting device, such as a guillotine or a rotary cutter, which severs the fibers at specific intervals, creating individual fiber segments with a crimped or wavy structure.
Heat Setting: To fix the crimp or wave structure in the fibers, they are then subjected to a heat-setting process. The fibers are heated to a temperature above their melting or softening point, which allows them to reshape and set into the desired crimp or wave structure. The heat-setting process typically involves passing the fibers through a heated chamber or over heated plates, followed by rapid cooling to solidify the fibers in the desired shape.
The specific parameters, such as the pressure applied during crushing, the cutting interval, and the temperature and duration of the heat-setting process, can be adjusted to control the degree and type of crimp or wave structure imparted to the fibers. The resulting fibers with crimp or wave structure can be used in various applications, such as in textiles, nonwovens, and other fiber-based products, to achieve desired bulkiness, resilience, and other functional properties.