Lock Stitch Model

1.1 Introduction:
In this chapter literature review of class 401 the consumption of thread is explained. Initially stitch and stitch classes are defined and elaborated, theoretically stitch model of lock stitch model are also explained and consumption of lock stitch is also explained according to Union’s Technical Bulletin. Seam classes are also explained and classified by according to their structure and specification. History of lock stitch and lock stitch machine is defined with its features and application. Factors affecting characteristics of thread are also explained these are fiber content, twist, ply, finishes, color, structure and size. Some parameters affecting the thread consumption are also explained which are sewing thread consumption,

In this class, the single yarn goes from one side of the fabric to the other side. A shuttle type needle with the eye in the center is normally skillfully used. The pick stitch or saddle stitch can be positioned in this stitch category that is used to outline the lapels of the jackets. A stitch in which the uncovered thread length on the fabric face is no longer than the thread width is known as the pick stitch. Saddle stitches have longer uncovered thread lengths. Stitch type 202 contiguous stitches share the same needle hole in back

These stitches are made by at least three yarns – needle thread, upper and lower cover threads as shown in fig 1.10.A self-governing looper is present in class 606. Cover threads held in place by needle threads and lie on the top face, interconnected on the rear of the seam by looper threads with the two covers over raw ends. Joining underwear and swimwear are its common applications.

Figure 1.10 Covering chain stitch
1.3.7 Class 700(Specialized lock stitch):

For a particular lock stitch using a single thread, class 700 is used. The arrangement of a lockstitch needs that the needle thread loop be covered around a second thread loop, which is a reel in the 300’s class. There is a nonstop needle thread single thread system in this class. Before starting each stitching series, an under spool is mechanically filled from the needle thread deliver. The base thread interconnects with the needle thread that has been wrapped around a spool. It is applicable only to short length seams or edging because this is a less ordinary stitch classification. The first stitch has been used in tacking and trunk button sewing and has no loose