What is shoddy yarn?
Shoddy is the name given to an inferior woollen yarn made by shredding scraps of woollen rags into fibres, grinding them and then mixing them with small amounts of new wool. The object was to manufacture a cheap cloth which could be made into products and clothes. It was also known as Rag-Wool.
Which test is carried out for textile yarn?
ASTM D4158 Testing Standard for textile abrasion recognizes the multitude of factors contributing to a fabric’s resistance to abrasion, like fiber properties and dimensions, yarn structure, and added treatments such as chemicals.
What is NEP in textile?
A nep can be defined as a small knot (or cluster) of entangled fibres consisting either entirely of fibres (i.e. a fibre nep) or of foreign matter (e.g. a seed-coat fragment) entangled with fibres. In most cases, fibrous neps are found to contain at least five fibres, with the average number being 16 or more.
How Neps are formed?
Almost any mechanical process can cause the formation of neps, but the most likely ones include harvesting, ginning, and opening/cleaning in the textile mill. Neps are generally removed from the cotton fibres at only two places in the textile mill: the carding machine and the combing machine.
How is shoddy made and what is it used for?
Shoddy is a low grade cloth made from the by-products of wool pressing or from recycled wool. One of its main uses was in the manufacture of soldiers uniforms. It is made from the longer fibre material produced by the recycling process. Mungo is made from the short fibre material and is used to make felt, etc.
Why synthetic fiber Cannot be tested by microscopic test explain it?
Synthetic fibres are very similar in appearance and the increase in the number of varieties makes it a little tough to distinguish the fibres even under a microscope.
What is yarn testing?
Yarn test methods that are used when values such as tenacity, elongation or shrinkage are determined. Test room conditions. Linear density. Breaking force and elongation at break.
How do you control Neps in carding?
The most critical setting in a carding machine is between cylinders and flat can be close as 0.2 to 0.25 mm; neps are directly affected by this setting. Very close setting increase the flat waste. Normally the setting between the feed plate and licker in is around 0.45 to 0.7 mm.
How can I reduce my Neps carding?
The number of neps above critical nep size shall be eliminated in carding by optimising setting, grinding frequency, wire condition/replacement, suction, process parameters, etc. It is to be noted that neps below critical nep size will not influence yarn quality/fabric appearance significantly.
How do you reduce neps in yarn?
When flat speed increases, it reduces the neps content and short fiber content of sliver and increases the fiber parallelization, thus decreasing the unevenness. Irrespective of the flat speed, the yarn unevenness increases as the yarn becomes finer as expected.
What is heat setting in synthetic yarns?
Synthetic yarns like nylon and polyester are typically known for their high shrinkage rate. In order to permanently set the physical properties of these materials after extrusion, they are stretched or drawn at elevated temperatures under tension during the manufacturing process, also known as heat setting.
Which yarns shrink the fastest?
Hot Air Shrinkage Test for Yarn & Cord Explained Synthetic yarns like nylon and polyester are typically known for their high shrinkage rate.
How do you measure shrinkage in ASTM d4974?
The percent shrinkage is read directly from a scale or display on the instrument while the specimen is still under tension and exposed to heat. The standard ASTM D4974 testing method is to heat the sample to 177 deg C for 2 minutes with a pretension load of 0.05 grams per denier.
What is the difference between high shrinkage and low shrinkage yarns?
A standard high shrinkage industrial yarn, in a rubber hose for example, will constrict the ID of the hose during vulcanization. Low shrinkage yarns (those that have been heat-set under the proper conditions) are designed to be more physically stable when exposed to heat and are a much better selection for this type of product.
