Sewing operations

It is important that the amino resins used in the postcure process should ( /) not react with the fabric before it has been fashioned into a garment, and (2) release a minimum amount of formaldehyde into the atmosphere, especially while the goods are in storage or during the cutting and sewing operations. These requirements are met, at present, with the diethylene glycol modified DMDHEU resin. 

Powdered polyethylene is also used to bond cloth interliners to garments. Automobile carpets are often made with a polyethylene rather than a latex backing because the polyethylene-backed carpet can be heat-formed so that the carpet will fit the shape of the car floor and cutting and sewing operations are consequently eliminated. 

There are a huge range of styles and constructions used in bras (Table 7.9). Construction is complex, with as many as 30 different sewing operations. Fabrics are selected for their elastic properties (one-way and two-way stretch), for example, as well as support and comfort. They may also contain underwires, hooks, eyes, and other fastenings. 

Operator handling can also affect seam performance, and it is important to train the sewing operators to guide the fabric into the sewing machine without stretching the fabric excessively. Excessive stretch of the fabric when feeding the fabric into the seam can result in poor seam appearance, poor seam elasticity and poor garment fit. 

In the apparel industry, the assembly process involves a set of workstations in which a specific task is processed in a pre-defined sequence. Before production, in order to achieve a balanced line, the sewing line supervisors assign one or mote sewing operatives to each task based on the standard time required to complete the task. However, industrial experience shows that it is difficult to achieve a perfectly balanced line because the production rate of each workstation is different. Imbalance occurs due to various factors, including fluctuation in operative efficiency, frequent change of product style, order size, prior experience and some unexpected factors, such as absenteeism, machine breakdown, and so oa Line balancing control is required to smooth away the bottlenecks. 

Textiles are made from a very limited list of a dozen or so structural fibers. From these, products must be made with millions of different specific end-use properties. In many cases the inherent properties of the fiber itself and substrate structure do not inherently impart the desired properties of comfort and func-tionahty, for example, water repellent, stain block, soil release, crease resistant, flame refardant, antifungal, rot resistant, stiff, soft, antistatic, stretch, recovery, antiseam slippage, and enhanced tearing strength. Thus, fabrics must be finished either to overcome the inadequacies of design or to fine tune the attributes of fabrics, not only for the end uses noted above but also for facilitating cut-and-sew operations (e.g., needle lubrication, anticurl). 

Fabric surface property, weight and thickness also influence cutting and sewing operations. 

The kind of garment to be sewn and the shape of the cutting parts define the types of operations. Seam length and the shape of seam contour influence the number and the type of technological operations. The technological sewing operations differ according... 

Computerised sewing machines generally are a lockstitch (301 stitch type) sewing machine. An operator terminates a typical lockstitch sewing operation as following ... 

Rocha, A.M., Lima, M., Sousa, E., Araujo, M., 1992b. Evaluation of sewing performance and control of sewing operation. In Second International Clothing Conference, University of... 

This issue, particularly relevant in the past, is now perceived less as a problem. The end of a mat roll can be sewed onto the initial part of the successive roll, and this is done by hand. Every roll lasts from 1 to 3 h at an average speed this means that, if many rolls are used simultaneously, the sewing operation can be required at such a frequency that it becomes very expensive. Besides, the mat should be handled and directed with greater care than roving. 

Assembly seam. Seams of this type are especially important for tool loading and the injection process. The sub-preforms can be assembled by using suitable types of threads, which again assist the sewing operation. The preform assembly can either be two-dimensional or three-dimensional and the respective stitching parameters can be chosen to be different. 

To specify the threads for FRPC manufacturing, it is obligatory to know the thread behavior throughout the process (fixym material lay-up to FRPC formation) and the impact of the selected thread on the quality of the finished product. Thus, the pre-selection of a thread for a specific sewing operation is a must. 

In the overall preform manufacturing concept, the fixing and positioning seams, and the assembly seams have a tremendous contribution. The sewing operation should be performed at a very high speed with secured quality and at... 

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