# Textile Calculation

Problems and solutions of textile

## Important Formula for Knitting Production

Important Formula for Knitting Production
Rofiquzzaman Raju
Fabric Technologist,
B.J.Group, Mawna, Gazipur

Introduction:
Knitting is a method by which thread or yarn is used to create a cloth. It is the interlocking of one or more yarns through a series of loops. In case of knitting production, knitter or knitting master has to apply some formula. In this article I will give some essential formula which will be effective for new comers in knitting.

Essential Formula for Knitting:

WPI: Wales per inch is called WPI.
CPI: Course per inch is called CPI.

GSM: Grams per square meter of the fabric are called GSM.

Needle calculation:

• Single jersey circular knitting machine needle = ∏DG
• Rib/Inter lock /Double jersey circular knitting machine needle = ∏DG×2 (two needle bed is here)
• Single bed flat knitting m/c’s needle = width× gauge
• GSM = {WPI× CPI × (39.37)2×stitch length (mm) ×Tex /1000× 1000} g/m2
• Stitch density = (WPI × CPI) inch-2 = (WPC ×CPC) cm-2
• No of sinker = No of needle
• No Wales =No of needle
• No of course = No of feeders =No of yarn (per revolution of cylinder)
• Course per minutes = No of feeders ×cylinder rpm
• Course length = yarn required for each course. = No of needle × stitch length
*** V bed flat knitting m/c’s needle = 2× width× gauge

Here,

D = cylinder diameter ,G = Machine gauge ,Needle pitch = 1/G.

*** Fabric width = wale spacing ×Total no of Wales
= (1/WPI ×No of Needles) inch
= (No of Needles/WPI× 39.37) meter

*** For single jersey fabric = (∏DG/WPI×39.37) meter (open width)
= (∏DG/WPI×39.37) meter/2(Folded/Tubular width)

*** For double jersey fabric = (2 × ∏DG/WPI×39.37) meter (open width)
= (2×∏DG/WPI×39.37) meter/2(Folded/Tubular width).

*** Fabric Length = Course spacing ×Total course pr hour
= {(Feeder× cylinder rpm× 60)/CPI} inch/hour
= {(Feeder× cylinder rpm× 60)/CPI ×39.37} m/hour