How High Temperature Fiberglass Sleeve is Made
Materials that resist catching fire, burn slowly, or retard burning can be described as either "incombustible", "non-flammable", "non-combustible", "fire-resistant" or "fire-retardant". "Self-extinguishing" materials cease burning once the flame or heat source is removed. "Fireproof" is understood to mean that an object cannot burn, but few materials are truly fireproof.
Most of our products fall within one or more of the above descriptions: they resist high temperature, flame, fire, molten metal splash and weld splatter very well but may melt with prolonged exposures past their designed maximum continuous operating temperature. They can also provide OSHA, ANSI-FM & NFPA compliance and personnel protection.
Using our products to retain heat or cold within pipes, hoses, enclosures or equipment helps conserve energy and resources, and reduces operating costs.
AB Technology Group: Keeping Our World Cooler ä. All products are non-asbestos and 100% asbestos free
The majority of electrical insulating sleeving produced is braided with fiberglass yarns. This yarn is purchased in single strands composed of continuous multi-filament fibers. It is received in, what is referred to because of its appearance, a large “milk-bottle” package with 0.7 turns per inch in the Z (reverse) twist direction ready for “uptwisting” on our twist frames.
In this first operation, we “uptwist” or increase the number of twists per inch in the yarn (in the same Z-twist direction) to a pre-established 4.0 turns per inch to achieve a uniform product which will process more smoothly. The material, which is now on a double-flanged plastic bobbin, is now ready for plying on our ply frames.
In this operation, two or more yarns are “plied” by twisting the strands in an opposite S (forward) twist direction into a multiple-end yarn product. The primary reasons for plying are to produce a “balanced” yarn and to increase its diameter and tensile strength. Upon completion of this step, the yarn again is in a “milk-bottle” package and it is now ready for winding.
The next step in yarn processing takes place in our Winding Department where the plied yarns are transferred to “braider packages” suitable for use on the braiding machines. The winding is also used to combine different yarn constructions which give us the ability to braid a variety of sleeving sizes ranging from a #28 - #30 AWG wire size to a 6” I.D.
Braiding is done on braiding machines in a variety of sizes ranging from small 8-carrier units, generally used to braid very fine yarns, to some with as many as 144 carriers used to braid larger-sized sleevings with inside diameters up to 6 inches.
In the braiding operation, one-half of the carriers (spindles on which the wound “braider packages” are mounted and rotate) travel in a clockwise direction while the other half travel counterclockwise, all following a figure-eight pattern. This interlacing process transforms the wound yarn into a continuous tubular braid or sleeving.
Although most sleeving is produced in standard wall thicknesses, heavy walls, as well as double- and triple-wall constructions, are available. Overbraiding on customer-supplied wire, cable, hose, and a variety of other items can also be performed, thereby eliminating a costly step in the customer’s manufacturing processes.
A close examination of some braided material would reveal fine, hair-like projections, or “spikes”, protruding from the braid. These actually are broken filaments of glass which must be removed.
Heat Cleaning (Normalizing)
Normalizing is a proprietary heat cleaning process that not only singes the braid to remove the “spikes” we have just mentioned, it also removes a controlled amount of the sizing, or lubricant, introduced during the yarn manufacturing process thereby providing for better adhesion of the subsequent application of various insulating compounds.
The tower rooms, which get their name from the tower-like structures which actually are huge vertical ovens, are where the braid receives any one of a variety of treatments or coatings designed to satisfy specific electrical, thermal, chemical and/or physical requirements.
After the braid is coated, the sleeving is drawn up, in continuous lengths, through the oven where a precisely-controlled temperature cures the coating to a tough, yet flexible, finish. Our large-sized coated sleevings are available in 3 to 6 foot lengths only and are both coated and cured utilizing a batch-type process.
24 Carrier Braiding Machine
"Milk Bottle" Yarn Spools