Gray Inspection and Stitching

The general sequence of processes carried out on gray cotton cloth    

  >   >   >   >>>>Gray Inspection      Stitching   >        Mechanical Cleaning          Singeing          Desizing        Scouring          Bleaching          Mercerising          Dyeing/Printing           Finishing

Gray Inspection

Gray fabrics are checked whether it conforms to standards or not, and all weaving faults are marked out. Fabric inspection involves three possible steps: perching, burling and mending. Perching is a visual inspection and the name derives from the frame, called a perch, of frosted glass with lights behind and above it. The fabric passes through the perch and is inspected. Flaws, stains or spots, yam knots and other imperfections are marked. Burling is the removal of yam knots or other imperfections from the fabric. The faults are then mended and any knots in the material are then pushed to the back. Mending is obviously, the actual repair of imperfections. Knotting should be done carefully and thoroughly so that the repair or holes is not visible.

Stitching

After the goods have been inspected and checked they are classed in the gray room, according to quality and stamped. Goods of similar weight, width and construction and the goods which will receive a similar treatment are sewn together, end to end, by sewing machines especially constructed for this purpose and each batch is given a number called lot number. The fabrics are usually sewn on circular machine. Stitching should be done in such a manner that the creases in fabric at the time of stitching should be avoided. The use of proper stitching thread is necessary to avoid stitch marks during colour padding. For heavy fabrics intended for mercerizing and continuous operations, the seam should be wider (15 mm) and stronger.

The pre-cleaning of gray fabrics may be carried out in a separate unit just before cropping and shearing operations. The purpose of brushing is to remove the short and loose fibres from the surface of the cloth. It also removes husk particles clinging to the cloth. Brushing is mainly done to fabrics of staple fibre content, as filament yams usually do not have loose fibre ends. Cylinders covered with fine bristles rotate over the fabric, pick up loose fibres, and pull them away by either gravity or vacuum. The raised fibre ends are cut off during shearing operation. Brushing before cropping minimizes pilling.

Shearing is an operation consists of cutting the loose strands of fibres from either surface of a fabric with a sharp edged razor or scissors. By manipulating the shearing it is also possible to cut designs into pile fabrics. Good cropping is perhaps, the simplest way of reducing the tendency of blended fabrics to 'pill'. In the case of cotton fabrics, in particular, care should be taken to see that the shearing blades do not scratch the surface of the fabric, which otherwise can cause dyeing defects during subsequent dyeing.

In this operation, the fabric to be sheared is drawn between a shearing bed and the shearing device which consists of a shearing cylinder and a ledger blade. The distance between the shearing device and the shearing table is adjustable so that it can be adapted to the thickness of the fabric and the depth of cut required. One or several shearing devices may be provided depending on the particular type of shearing machine. They are arranged in such a way that both sides of the fabric can be sheared at the same time.  Rotating brushes are installed both in front of, as well as behind, the shearing device to align the fibres correctly for shearing and remove cut ends after shearing.