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Seam Engineering: Stitchless Seam Technology


OBJECTIVE: The aim of this Small Business Innovative Research (SBIR) opportunity is to systematically investigate and analyze current and evolving stitchless seam technologies, and to evaluate their use in existing Navy clothing end-items. The desired end result would be a reduction in bulk and weight, enhanced performance characteristics such as moisture management (breathability), wind/water resistance, durability, abrasion resistance, flexibility and improved ergonomics. In conjunction with improved technical performance, a reduction to end item costs will be realized through manufacturing efficiencies given the speed of the proposed processes. Furthermore, rapid prototyping of test quantities could be employed using the selected technology in support of developmental garment programs versus current cost-prohibitive approaches. DESCRIPTION: Historically, production methods for clothing manufacturing involve traditional labor intensive mechanical stitching processes in conjunction with operator precision which involves a variety of stitch types, each utilizing a specific sewing machine. The construction of a typical garment would incorporate many stitch types and associated machines requiring virtually endless transportation from station to station as the garment is formed. Detrimental to the garment performance and functionality are overlapping and complex seams in areas such as the crotch, armhole, neck, cuff, pocket, waistband, and hems. These areas are the source of increased bulk and a source of abrasion and potential failure. In the case of high performance technical apparel, seam sealing tape is applied to the sewn seam to prevent penetration of liquids, chemicals and particulates. This seam sealing operation can add as many as eleven yards of tape to a garment, thereby increasing bulk, weight and stiffness. The process of sewing and seam sealing adds approximately 25% to the manufacturing costs and therefore presents a fine opportunity to realize cost savings. PHASE I: Phase I will examine and rank novel stitch-free technology processes currently in development by manufacturers. The investigation would include welded seams, adhesive techniques or unique bonding mechanisms. Promising concepts will be produced and compared to traditional sewn seams using a variety of internationally recognized standards and test methods such as those referenced in International Organization for Standardization (ISO), ASTM International, and the American Association of Textile Chemists and Colorists (AATCC) to determine the most appropriate candidate technologies prior to down selection and subsequent assembly of pre-prototype garments. Tests of interest will include bonding/seam strength, hydrostatic pressure resistance, stiffness, dimensional stability and durability predictions. Results documenting the potential viability of novel seaming techniques into Navy garments will be compiled into a final report with recommendations for Phase II. It is also envisioned that leap ahead technologies would emerge and could be pursued in later Phases of the effort. PHASE II: The focus of Phase II will be to design, develop and test prototype garments utilizing the best candidate stitch-free technologies selected from Phase I and to conduct a manufacturing feasibility analysis. A standard Navy garment will be chosen as a demonstration model but it is anticipated that the Parka, Navy Working Uniform (NWU) which utilizes both traditional stitching and complex seam sealing techniques would be an excellent example to assess the technologies"viability. Garments will be developed and subjected to laboratory durability prediction assessments using multiple shipboard launderings, prior to laboratory testing. The best candidates will be subjected to a limited shipboard and shore side user evaluation. Following the wear test, they will be evaluated through objective laboratory assessments and by collecting user feedback through focus groups to determine performance, durability, reduction of bulk and weight, operational compatibility and ease of care. PHASE III: Equipment and processes will be optimized for the selected technology which will transition to end items on a prioritized basis and accompanying technical data packages updated to reflect the changes. PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Alternate seam technologies are employed in a variety of garment manufacturing processes. They have been in the commercial market for several years, however situations where seam strength is critical, the alternative solutions did not create satisfactory results. Some manufacturers in the commercial sector have adopted stitchless seam technology in recreational garments in the areas of pockets, zippers and other"non-stress"seams. The technologies have evolved dramatically and are worthy of consideration. This initiative will analyze the technology improvements.
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