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Md Sohanur Rahman Sobuj

Student of Bangladesh University of Textiles (BUTEX) Department: Apparel Engineering

Graphical Representation of Mass Variations

Graphical Representation of Mass Variations Graphical representations are aimed at providing easy analysis possibilities as well as providing more complete information than the numerical estimates. The following graphical representations are common with the latest generation evenness testers. Spectrogram  3D Spectrogram  Variance Length Curve  3D Variance Length Curve  Normal Diagram  Cut Length Diagram  Histogram Spectrogram The […]

Yarn Evenness II It’s Classification

Yarn Evenness & It’s Classification Evenness, Unevenness, regularity, and irregularity are common terms used to describe the degree of uniformity of a textile product. In the textile field, the uniformity of products like the lap, sliver, roving or yam is expressed in terms of evenness or regularity or in terms of unevenness or irregularity. A […]

Unevenness and Coefficient of Variation of Yarn

Unevenness and Coefficient of Variation of Yarn: The average value for all the deviations from the mean which is expressed as a percentage of the overall mean is called percentage of Mean Deviation (PMD). The coefficient of mass variation CV % is the ratio of standard deviation of mass variation divided by average mass variation.

Index of Irregularity

The ratio between the actual irregularity present in the material and the calculated limit irregularity is called index of irregularity. It is denoted by I. Accordingly the best yarn have a value of I = 1. Thus, the higher value of I indicate that the yarn is more irregular. On the other hand, the CV of the most regular/uniform strand of material in which the fiber ends are laid in a random order in the sliver, roving, or yarn is called limit irregularity.

Study on four truck circular knitting machine.

Most single-jersey fabric is produced on circular machines whose latch needle cylinder and sinker ring revolve through the stationary knitting cam systems that, together with their yarn feeders, are situated at regular intervals around the circumference of the cylinder. The yarns is supplied from cones, placed either on an integral overhead bobbin stand or on a free-standing creel, through tensioners, stop motionsand guide eyes down to the yarn feeder guides.

Methods of Evenness Testing

The optical method measures the variations in diameter of a yarn and not in its mass. The instrument an infra-red transmitter and two identical receivers. The yarn passes at speed through one of the beams, blocking a portion of the light to the measuring receiver. The intensity of this beam is compared with that measured by the reference receiver and from the difference in intensities a measure of yarn diameter is obtained.

Speed Frame Production Calculation

Math 1: Calculate the TPI (twist per inch) produced on a simplex with diameter of front roller 28 mm and its rpm be 30. The rpm of flyer is 1000.

Twisting and Amounts of Twist for Different Materials – why is the amount of twist in a yarn important

The roving coming out of the front delivery roller is threaded through the top of the flyer, passes through its hollow leg around the presser arm on to the bobbin. The purpose of providing twist in roving is to give the strand sufficient strength to withstand the strain during unwinding in the creel of the ring frame. The insertion of twist is achieved by the rotation of the flyer.

Shaded Twill Weave and Stepped Twill Weave

Shaded twill is formed shade effect on the surface of the fabric. The shade effect is created by the combination some thick to thin twills and thin to thick twills. Stepped twill is formed by steeping a continuous twill and keeping the direction of twill line same or opposite.

Elongated Twill Weave and Combined Twill Weave

Elongated twill is constructed by advancing the points of intersection two or more threads in one direction and one thread in the other direction.On the other hand combined twill is formed by combination two regular twill and arranging them alternately with each others.