Effects of Sewing Thread Tension on Knitted Fabric by Overlock Stitch

EFFECTS OF SEWING THREADS TENSION ON KNITTED FABRIC WITH OVERLOCK STITCH

Under The Supervision of

Dr. Biswapati Chatterjee

Submitted by:

SK Mosaib Ahamed

Tatai Kr. Biswas

Sajib Paul

CHAPTER I

1. INTRODUCTION

In a garment industry a wide varieties of sewing machines are used and produce different types of stitches which are used for joining of woven and knitted fabrics for making garments such as formal shirt, casual shirt, t-shirt, sports-wear, party wear etc.The garments produced from woven fabric generally use the lock stitches.Similarly for a garment produced from knitted fabric specific classes of stitches namely overlock stitches are widely used.The over-lock stitch produces less puckering,secures the edges of the seam and reduces the failure of seam.There are large number of machine manufactures producing the over lock sewing machines.These machine are having a characteristics machine parameters(needle size,needle thread tension,looper thread tension,pressure foot pressure,feed dog ,machine speed,stitch per inch etc) which can vary the performance of lock stitches.Depending upon the variation of machine parameters a few literatures available with lock stitches but literatures on over-lock stitches are rarely reported although overlock stitches are considerably used in apparel industry.

It is generally understood that in a sewing machine revolution per minute (R.P.M), pressure foot pressure, stitch per inch (S.P.I), Sewing thread tension (Needle and Bobbin), feed dog etc affect the stitch performance or quality for lock stitch. Similar knowledge with overlock stitch are rarely reported in thel literatures.The number of process parameters in lock stitch affecting the seam performance are quite large (raw materials two types: 1.fabric 2.sewing thread.Fabric also two types a.single jerssey b.double jerssey and one single type thread namely core spun thread having same...