CHAPTER 10 FABRICATION AND MANUFACTURE

CHAPTER 10 FABRICATION AND MANUFACTURE Learning Objective: Upon completion of this chapter, you will be able to identify and understand the tools, equipment, and procedures used to cut, layout, and fabricate specified projects. As an Aircrew Survival Equipmentman, you need to know what materials are best suited for the job at hand if you are to be considered a master craftsman of your trade. Therefore, to lay the groundwork to aid you in becoming a skilled PR, this chapter discusses the textile materials, tapes, webbing, thread, cards, knots, and seams you will use. Many of the repairs you will be required to make can be accomplished by replacing missing or worn hardware. There are occasions when minor repairs require hand sewing because machine sewing is impractical or impossible. For instance, it might be advisable to make minor repairs to aircraft upholstery by hand sewing the repair in the aircraft rather than by bringing the item to the shop. On the other hand, most sewing is done by a sewing machine. A seam is usually constructed faster, and is more durable, when a sewing machine is used. The use of a sewing machine gives the seam a better appearance. To do your job right, you must know the types of handmade and machine-made seams and how to make them. TEXTILE MATERIALS, TERMS, AND MEANINGS When a PR talks about warp, he doesn’t mean something’s out of shape; and when he talks about filling, he isn’t referring to teeth. He’s using terms textile manufacturers use, terms that are standard throughout the textile industry. The Navy uses these standardized textile terms to identify and classify materials on Navy stock lists. Aircrew Survival Equipment Changes and Bulletins also contain some of these terms. To comply with these repair instructions, you must first understand the terms used in them. FIBER AND FILAMENT Fiber is the basic unit used in the fabrication of textile yarns and fabrics. Vegetable, animal, and mineral fibers are natural fibers; nylon, dacron, and rayon are synthetic fibers. A filament is an individual strand of material, and can be any length. Filament is also another word for fiber, usually used when indicating or referring to synthetic fibers. A fiber, or filament, is the smallest unit in any type of cloth. An example is a silk filament, which may vary in length from 300 to 1,000 yards. Synthetic filaments may be several miles long. S t a p l e The staple is the smallest unit of a naturally occurring fiber, or a synthetic filament cut in short lengths to be combined with other fibers in the manufacture of a variety of materials. When used in reference to the naturally occurring fibers, it denotes quality or fineness, such as “long staple” cotton. Yam Yarns are continuous strands of textile fibers or filaments, in a form suitable for manufacturing textile materials. The strength of the yarn is influenced by fiber strength, size, and length; size of the yarn; and tightness of twist. The strength of textile fabrics is determined by yarn strength and weight. You may form yarn by any of the following processes: a number of fibers twisted together, a number of filaments laid together without twisting, or a number of filaments twisted together. Yarns formed by twisting a number of filaments together are referred to as multifilament (many filament) yarns. Ply yarn is two or more single yarns twisted together. 10-1