Optimization of Spacer Size and Degree of Shore Hardness on Yarn Quality in Ring Frame Machine

Research Article

Adv Res Text Eng. 2021; 6(1): 1058.

Optimization of Spacer Size and Degree of Shore Hardness on Yarn Quality in Ring Frame Machine

Shiferaw M* and Muhammed A

Department of Textile Engineering, Ethiopian Institute of Textile and Fashion Technology, Ethiopia

*Corresponding author: Mesfin Shiferaw, Department of Textile Engineering, Ethiopian Institute of Textile and Fashion Technology, Bahir Dar, Ethiopia

Received: December 17, 2020; Accepted: January 12, 2021; Published: January 19, 2021


This study was mainly focused on the optimization of spacer size and degree of shore hardness in ring frame drafting systems to improve yarn quality parameters. The 100% cotton fiber carded yarn samples of 35.5Nm were produced to analyze the effect of spacer size and degree of shore hardness with different combinations. The spacers were 4.2 and 4.5 mm and the shore hardness was 70 back & 62 front and 70 back & 65 front. All yarn samples of the same count were produced on the same spinning positions by changing the spacer’s size and degree of shore hardness by keeping all other parameters constant. The produced samples were tested according to standard testing methods and instruments. After testing, the tested results were compared to analyze the influence of spacer size and shore hardness on yarn quality in a ring spinning frame. The technologist needs to understand this and act on it to optimize the yarn production. The specific size of the spacer with specific shore hardness should be used for a particular count of yarn. The results showed that yarn quality i.e. U%, Cvm, Neps +200%/km, Thick +50%/km, Thin -50%/ km, TIPI are considerably influenced by the spacer size with different shore hardness. So it is concluded that the best result has been obtained in the case of using a pink color spacer (4.2mm) with 70 degrees back and 65 front degree front top rollers.

Keywords: Spacer size; Shore hardness; Ring frame; Yarn quality


Spinning is a part of the textile manufacturing process where the fibers are converted into yarn by passing through certain processes like Blow room, Carding, Drawing, Roving, Ring Frame, and finally winding into yarns. In the blow room, the raw material will be open and clean the impurities on the surface by bland of mat machine and passes into carding machine in the form of the chute. Carding is the heart of the spinning process. This is where the flock from bales was open into an individual fiber. Thus, it is ease to remove the excess impurities from the fiber surface. At this point, short fiber will be eliminated and form a carded sliver. The carded sliver is fed into breaker draw frame and finisher draw frame to parallelized, straitening, to improve yarn irregularity by doubling, drafting, and drawing. Ring spinning is one of the most common effective spinning techniques in yarn manufacturing process. It provides excellent yarn properties compared to other spinning systems. However, it is limited by relatively low traveler speed, high balloon tension, low spindle speed, and high spinning triangle size. These limitations are responsible for lower production rates than the rotor, air-jet, and friction spinning systems. Despite low production, ring spinning provides a yarn structure that yields excellent mechanical properties. Yarn quality is the main goal of the company to achieve the expected aim. But there are some parameters that affect yarn quality. These are yarn unevenness, total imperfection (nep, thin and thick place), and coefficient of mass variation. The distance between the lower edge of the top cradle and bottom apron nose bar determines the distance between the bottom and top apron. This in turn determines the intensity of pressure applied to the fibers to under control. This distance which is introduced by means of a special device is called a spinning spacer. The purpose of the introduction of apron drafting is to have adequate short fiber control during the drafting process. These short fibers are to be carried with full control along with the surface speed of the second roller as close as possible to the nip and pass forward. Until the fiber is gripped at the front nip, it is expected to be under the full control of the apron during its forward movement. Thus a positive apron control is governed by shore hardness. Any deviation of the apron control from the optimum values will lead to a distorted drafting process; were revolving in the proper selection of shore hardness, is also detrimental to yarn. The operation of the ringspinning system can be divided into drafting, twisting, and winding steps. The drafting step plays an important role in the quality of yarn. Various studies were conducted regarding the drafting parameters of spinning systems to improve the yarn quality. In the ring frame drafting system, the spacer is the element that decides the distance between the top apron and the bottom apron at which the short fibers are mainly to be controlled.

Literature Review

The drafting parameters of ring spinning that affect the quality of yarn are drafting angle, drafting roller setting (front and back zone gauge), top rubber-coated roller hardness, cradle length, top roller pressure, aprons hardness, and spacer size. Each mentioned parameter contributes to the quality of spun yarn. The quality of the yarn is measured in terms of yarn evenness, yarn imperfections (thick, thin, and nep) [1]. According to Bhaveshkumar K et al., in their research, study the effect of spacer size on the yarn quality due to the apron slippage. The distance between the top and bottom apron is larger than the optimum value the yarn U%, neps, thick place increases due to the ineffective short fiber control and if it is too less than also U% and thin place are higher due to higher percentage of long fiber damage. The ring frame spacer size is to be decided according to the yarn count to be spun because the yarn count decides the bulk of fibers material present in between the two aprons during drafting. There are two types of apron yarn guidance, which are a single apron and a double apron. Double aprons are the most effective for yarn guidance [2]. Drafting roller and apron has greater importance in determining process efficiency and yarn quality. The influence of the top roller cots material on the final yarn quality has been established as this direct content with the fibers. Many researchers have studied this important subject. Broome investigated the influence of the cots material on the yarn prosperities and concluded that among the properties surveyed, the coating hardness had the greater effect on yarn evenness and coat usually soft rubber [3]. There have been many studies conducted regard to the assessment of machinery parts attached to the results of the spinning process. But as it seems, and the writer’s observation until now, there has not been a clear standard for rubber rollers above conditions (top roller) in ring spinning. In the same cases there is a standard rubber cot diameter, but this condition for special fiber processing only [4]. Starting from this fact, the writer ventured to try to conduct a study of the relationship between the quality and condition of the rubber roller on the results of unevenness (U%) yarn, thick, thin place, and nep. The flatness of a rubber roller in drafting system affects the quality of its yarns. Rubber rollers are any obvious defects that will result in conditions that are less yarn perfectly. In the event of the stretch, then for rubber rollers that are too loud or too soft, it will generate the conditions position the fibers in the yarn is uneven. Roller rubber hardness degrees is too low to process a particular fiber material, can produce floating fibers, and this happens because the stretch is not perfect (slip fibers). Looking for rubber rollers condition that the degree of hardness is too high (hard) can result in broken fibers, as if stretching occurs when the force’s exerted [5,6].

Materials and Methods


1. 100% Cotton was used to produce 35.5 Nm ring spun yarn. The cotton was tested under standard atmospheric conditions (20±2°C and 65% RH) (Table 1).