The suitabililty of Rayon fibers in Staple spinning processes - suitability of Rayon Staple fiber is discussed, in particular the fiber parameters, and enduser application.

Due to rising cost factors of raw materials, factory owners are made to face harsh realities: When purchasing Modal fibers with excellent fiber parameters, the procurement department has to make a

tough choice. 

It comes as no surprise, many factories in the Spinning sector will fall into this trap, for lack of knowledge of t responsible personnel could bring them to the brink of ruin. 

One must consider several factors : cost of raw material as the major factor in production cost, with a share of near 50 %. 

Considering a purchase of fiber, the following criteria is essential : 

Origin Fiber properties ( wet-, conditioned -, dry Tenacity, Elongation, shrinkage, Pilling resistance, etc.) are excellent indicators of fiber quality Staple length - obviously - is of extreme importance in order

to achieve final desired tenacity and Elongation Active fiber add on and its source (Origin and type of fatty Ester application as well as percentage) Price and Terms of fiber lot purchase Packing Date of Manufacture Storage of fibers (extremely important) Mode of shipment (sea-transport can cause problems, extreme temperatures always do) 

In my many years of managing Spinning Mills I came across various fiber Manufacturers world wide. Manufacturers outbid each other in order to receive a Purchase order. 

Fiber parameters

In normal temperate climates, fibers manufactured by a renowned supplier will be accompanied by sound warranties, and nothing or little can go wrong in the spinning process. 

Prime lots, however, carry a hefty price tag, and with margins in cents one would have to consider such choice carefully. 

Many Spinning mills in Europe went out of business, the fiber manufacturers are still operating. 

With competition coming on stream, lower grade raw materials are being used. One particular candidate is Cotton lint. One must imagine the lint being the base material, passing through the full caustic soda process, filtered and extruded. The fiber length of lint, passed through the process is in fractions mm. 

Financial Cost

As against Viscose derived from Nordic wood, with fiber lengths of 1-2 mm, the parallels are very far apart. So are the prices of the two. 

When a prospective buyer goes for a cheaper Viscose fiber, he must realize that he may have to prepare for essential modifications on his plant. In very few cases, personnel is able to adapt to changing fiber properties. When things go bad, the culprit is always the purchaser. 

Technical Personnel which handles issues on the manufacturing floor, normally are of limited capacity when confronted with such scenarios. They quickly point their fingers to the raw material, without considering that a change of raw material can bring financial advantages to the Employer. 

Changes required are often time consuming and need Expert knowledge in all Spinning processes. This has to be acquired over years, and will not be taught in Colleges. 

It will invariably involve first hand knowledge of Blowroom machinery, Carding -, Drawing, and subsequent Roving - and Spinning Machinery, i.a. Ringspinning -, OE-Spinning -, Airjet (MVS), as well as subsequent - Machinery, and its processes. 

When in the Spinning process high ends down, slubs, imperfections, are shown, then mostly the fault is not on the machine, but rather in the preparation. Standard Efficiency can never be achieved thus. 

other Details

In case with Microfiber, yarn cross sections would contain hundreds of individual fibers which must be controlled, guided, and this under the constraints of factors of speed, quality, and damage free processing. 

Not an easy task. For a novice an impossible one. 

continued : Fibers tend to lap in all processes, impairing production efficiency, quality. 

Published by:

Heinz Rainer - Technical Advisor