Test Specification

Determination of appearance quality of yarns made of cotton or man-made fibers, or their blends by winding on the blackboard. The test method is also applicable to the evaluation of the appearance quality of carding yarn, combed cotton yarn, air spinning yarn, etc. This test method is not suitable for evaluating the appearance quality of woolen yarn.

Nominal Definition

Yarn Appearance: Observe the yarn samples wound on the blackboard according to the prescribed requirements by a visual method, which to obtain a visual effect.

Slub: The projected width (hereafter referred to as diameter) of the yarn segment is thicker than the normal yarn diameter, the slub degree of which can be recognized by the inspector.

Thin Place: The segment diameter of yarn is smaller than normal, the fineness degree of which can be identified by the inspectors.

Shadow: Many yarns with thin diameter arranged together to form dark lumps on the surface.

Serious Defects: The slub with the diameter is 1-2 times thicker than the original yarn, and the length is more than 5cm. The thin place with the diameter is 0.5 times smaller than the original yarn, and the length is more than 10cm. The defect with the diameter is 2 times more than the original yarn, and the length of the defect is long than 1.5cm.

Systematic Unevenness: The thickness of yarn evenness is uneven and form a law, which accounts for more than half of the whole plate surface and even its shadow depth is deeper than the shadow of the standard sample.

Nep: An unbroken particles formed by the winding of one or more fibers.

Testing Procedure

1 Place the tester on the stable worktable. Connect the power supply and turn it on. Insert the blackboard into blackboard clip.

2 Press handle to put up nut from screw and left move to the fixed position.

3 Hitch the cop to the cop core, then fetch the thrum from yarn hook-oriented, next go through between weight base and press yarn flake, pass the guide bar, again traverse yarn hook-oriented, lastly wrap the thrum in blackboard gap on the left.

4 Choose the load weight according to the request and mount it on the gasket of the weight tension regulator. Then put strap on chose gear-shifting of density.

5 Press the start-up button, the blackboard starts turning around and the yarn is wrapped on it from left to right until the guide bar come into contact with the limit switch to stop. Then cut the yarn and take out the blackboard.

Grade Evaluation

When evaluating the grade, the yarn evenness and nep and impurity degree on the blackboard are compared with the standard sample, which is the main basis for evaluating the grade.

1 Shading and slub on the blackboard can not counteract each other, take the lowest as a rating.

2 The nep and impurity can not counteract with the evenness, take the lowest as a rating.

3 To lower one grade when the slub is thicker than the sample; to lower one grade when the slub number is more than the sample; to lower one grade when the slub is obviously thicker than the sample even though the slub number is less than the sample.

4 To lower one grade when the shadow is generally deeper than the sample; when the shadow is as deep as the sample, but the total area is larger than the sample, to lower one grade; though the shadow area is large, but the depth is shallower than the sample, do not lower the grade.

5 Serious defects and general systematic unevenness rating as second grade, serious systematic unevenness rating as third grade.