Enter the diameter of the lap roller, the RPM of the lap roller, and the efficiency into the calculator to determine the yarn production.

Yarn Production Formula

The following equation is used to calculate a Yarn Production rate.

P = pi*D*S/36 * 60 * 1/840 * n 
  • Where P is the production (lb/hr)
  • D is the diameter of the lap roller (in)
  • S is the rotational speed of the lap roller (rpm)
  • n is the efficiency of the system, (typically 75-90%)

This formula calculates the linear output of the roller per unit time, then converts it into units of weight per time using the known value of 840 yards of yarn per pound, then multiplies by the efficiency to get the final result.

What is a Yarn Production?


Yarn Production is a measure of the total weight per unit of time that a yarn machine can produce. In other words, it’s the output of the yarn roller.

How to Calculate Yarn Production?

Example Problem:

The following example outlines the steps and information needed to calculate Yarn Production.

First, determine the diameter of the yarn roller. In this case, the lap roller is measured to have a diameter of 10 inches.

Next, determine the rotational speed of the roller. This is measured to be 150 RPM.

Next, determine the efficiency of the roller. This roller runs at a 75% efficiency.

Finally, calculate the yarn production using the formula above:

P = pi*D*S/36 * 60 * 1/840 * n

P = 3.14159*10*150/36 * 60 * (1/840) * .75

P = 7.0124 pounds per hour


What factors can affect the efficiency of a yarn production system?

Several factors can affect the efficiency of a yarn production system, including the quality of the raw materials, the condition and maintenance of the machinery, environmental conditions such as humidity and temperature, and the skill level of the operators. Regular maintenance and quality control can help ensure high efficiency.

How does the diameter of the lap roller influence yarn production?

The diameter of the lap roller directly influences the amount of yarn produced because a larger diameter allows for more yarn to be wound around the roller per rotation. This means that with all other factors being constant, a larger lap roller can increase the production rate of yarn.

Can the yarn production formula be used for any type of yarn?

While the yarn production formula provides a general method for calculating the production rate, the specific characteristics of different types of yarn, such as thickness or material, may require adjustments to the formula. It’s important to consider the specific properties of the yarn being produced when applying this formula.