Question

The following is the most popular and quicker methods for measurement of Spirality in weft knit goods

• A. Photo copy method
• B. Heat set method
• C. Wash burns method
• D. Star fish method

Hint:

• Spirality A defect in knitted fabrics where wales are skewed relative to courses.
• Caused by unrelieved yarn twist/torque.
• Measurement involves determining the angle of this skewness.
• Photo copy method / Image analysis A common, quick, and practical method. A photocopy or scan of the fabric is made, and the wale angle is measured on the image.
• Spirality is often assessed after standard washing and drying cycles (e.g., AATCC TM139 for dimensional changes, which includes spirality).

Answer 1

The Correct Option is A

Spirality is a fabric defect primarily in weft knitted fabrics (especially single jersey made from staple spun yarns) where the wales (columns of loops) are not perpendicular to the courses (rows of loops) but are skewed or spiral around the tubular fabric or in a flat fabric. It is caused by unrelieved torsional stresses in the yarns used. Measuring spirality involves determining the angle of this skewness. Several methods exist:

• Direct measurement on fabric: Using a protractor or by marking a course and a wale and measuring the angle between them after a certain length. This can be done on relaxed fabric or after specified washing/drying cycles.
• Projection methods or Image Analysis: These are often quicker and more objective.

Let's evaluate the options:

• (a) Photo copy method (or Image analysis / Projection method): This involves placing the fabric sample on a flat surface (like a photocopier glass or a scanner bed) or projecting its image. The angle of the wales relative to a reference line (e.g., edge of paper, a marked course) can then be easily measured from the photocopy, scanned image, or projection. This is a relatively quick, simple, and widely used method for routine spirality assessment in industry and labs. Modern image analysis software can automate this.
• (b) Heat set method: Heat setting is a finishing process used to stabilize thermoplastic fibers (like polyester) or fabrics containing them. It's not a method for measuring spirality itself, though it can influence or set spirality if present.
• (c) Wash burns method (likely "Wash and Tumble Dry" or similar): Spirality is often assessed after one or more wash-and-dry cycles because latent stresses in the yarn relax during washing, and the spirality can become more pronounced (or sometimes reduce). So, washing is part of a test procedure, but "wash burns method" isn't a recognized measurement technique name.
• (d) Star fish method (or Starfish diagram): This usually refers to a graphical representation of fabric properties, particularly dimensional stability or distortion after washing (e.g., displaying changes in length, width, and spirality). It's a way to visualize results, not a primary measurement method for spirality itself. (Also, "star test" is a bursting strength test).

The "Photo copy method" or its modern equivalents (scanning, digital imaging) is indeed a popular, quick, and convenient way to measure the angle of spirality. By creating a 2D representation of the fabric structure, the wale angle can be directly measured. Therefore, this is the most fitting answer among the options for a "popular and quicker" method. \[ \boxed{\text{Photo copy method}} \]