New Directions in Braiding

It is the intent of this manuscript to provide a general treatment of braiding: past, present, and future. A history and evolution of braiding, braiding machinery, and related engineering developments is provided with emphasis on the design, manufacture, and analysis of braided fabrics and composites. Some recent developments are briefly described, including: 1. a composite braider with axial yarns which interlace with the helicals, and in which the helical yarns do not interlace with each other – a machine now under commercial development, 2. a new braided structure, called the true triaxial braid, produced by the new machine or by proper carrier loading on a conventional Maypole braider; and 3. a computer controlled take-up system using image analysis to monitor and control braid formation. Original work ongoing at Auburn University is described and involves Jacquard lace braids with open structures for use in composites, computer aided design (CAD), computer aided manufacturing (CAM), and analysis of ordinary and lace braids for composite applications. This paper is an expanded version of an invited presentation under the title “New Directions in Braiding” at a Fiber Society presentation in Bursa, Turkey, in the spring of 2010 [1]. INTRODUCTION Braiding has been identified as one of the key preforming technologies for producing low cost high volume composites [2]. The mechanical nature of braiding machines as well as the intrinsic properties of braided fabrics contributes to the overall engineering capacity of braided structures. Braiding is ideal for mixed material systems and rapid and limited production runs. Braids are used extensively in a multitude of industrial applications, including aerospace, automotive, civil infrastructure, engineered composite materials, marine, fashion, and textiles. Some examples of high performance commercial applications include multifunctional tethers, surgical stents, engineered ropes, turbine fan casings, aircraft propellers, inflatable structural beams, rocket nozzles, bicycle frames and wheels, and monocoque vehicle chassis. Braiding is used extensively in manufacturing industrial products such as reinforced hose. As engineering design and manufacturing automation continue to improve, new applications of braids will be realized. In order to present braiding as a viable composites pre-form technology it is important to provide some of its historical detail. The braiding machine design has been modified many times, as witnessed by the multitude of patents issued throughout the world. With each modification, the resulting products differ accordingly. The process parameters affect the characteristics of braided product and are thus important for a complete understanding of textile preform geometry of composite material reinforcement. This paper will provide a description of braiding technologies, both past and present, in order to provide context for current and future developments. Historical Context Braiding has been an important process throughout history of transforming fibers to more useful forms. It is arguably the first textile process, practiced by ancient civilizations [3]. Smaller, natural-fiber strands were braided in order to produce larger, stronger structures such as rope. Several online encyclopedias and other sources place the origins of braided rope at more than 17,000 years ago [4]. Ancient Chinese and Japanese documents record that braiding was in use before 4,000 BC [5-6]. Braiding in the context of ancient history is simply considered the oblique interlacing of three or more strands [6-7]. The original braiding machine predates the Industrial Revolution [8]. As mankind became more sophisticated, so did the methods of producing textiles, including braids. A modern definition of braiding is given by the German Industrial Standard DIN 60000 as "two or three-dimensional fabrics with even thread density