Spreading

Spreading

Spreading is a process by which plies of fabric is spreaded in order to get required length and width as per marker dimension. This is a preparatory operation for cutting and consists of laying.

In other words, spreading is the process of stacking of layers of fabric to allow simultaneous cutting. The marker is laid on the top most of the layers.

Factors considered for the ply height determination:

a) Thickness of the fabric:

When thickness of the fabric is more then numbers of plies should be less and numbers of plies may be higher in case of thin fabric.

b) Cutting knife height:

Lay height should maximum be 70% of cutting knife height.

c) Volume of production:

If volume of production requires, numbers of ply may be higher, i.e. height of the lay should be higher.

d) Nature of the fabric:

Ply height is determined by the nature of fiber by which fabric is made up. In case of same numbers of ply, cotton may be cut but man made fiber (synthetic) may not be cut.

Requirements of fabric spreading

Spreading must achieve a numbers of specific objectives. There are two types of requirements. These are i) Basic requirements (1-3) and

                           ii) Additional requirements. (4-10)

Requirements of fabric spreading are discussed below:

1. Alignments of fabric plies: 

Every ply should comprise the length and width of the marker plan, but should have minimum extra outside those measurements. The piece of fabric as delivered by the suppliers may vary in width; both from piece to piece and to a lesser extend within single piece. The marker plan is made to fit the narrowest width.

Inaccuracy in alignment could mean that plies do not cover the whole area of the marker plan and parts of some pattern pieces would be missing when cut.

2. Correct ply tension:

If the plies are spread with too slack a tension they will lie in ridges with irregular fullness. If plies are spread in a stretched state they will maintain their tension while held by lay, but will contract after cutting or during sewing, thus shrinkage the garments parts to a smaller size than the pattern pieces. So tension of every ply should be correct. This is one of the basic requirements.

2. Fabric must be flat:

The fabric laid on the table should be flat otherwise there may be ridges in it. To make the fabric flat, leveling equipments are used.

It is one of the basic requirements.

 

4. Elimination of fabric faults:

Fabric faults that are identified during the spreading process should be eliminated. The spreader cuts across the ply at the position of the fault and pulls back the cut end to overlap as far back on the next splice mark.

5. Correct ply direction and adequate lay stability:

These two factors must be considered together. They depend on the fabric type, pattern shape and the spreading equipments that is available. When the pattern pieces have been positioned in a particular direction in the marker plan, it is essential to spread the fabric maintaining that direction. If the pattern pieces are asymmetrical, all the pieces are face up and face down.

6. Elimination of static electricity:

In spreading, plies of fabric may contain synthetic fibers; friction may increase due to the charge of static electricity in the fabric. Friction may be reduced by changing the method of threading the fabric through the guide bars of the spreading machines. Humidity in the atmosphere of the cutting room may also be increased, thus static electricity to discharge continuously through the atmosphere. In some cases it may be necessary to earth the lay.

7. Easy separation of the cut lay into bundles:

Identification marks are used in to plies due to color and shade variation of the fabric. For this separation, low valued colored paper is used to plies.

8. Avoidance of fusion of plies during cutting:

In case of thermoplastic fabrics that made up with thermoplastic fibers may fuse during cutting if the cutting knife becomes hot as result of friction with the fabric.   We can prevent fabric from the fusion by:

a)      Using anti-fusion paper,

b)      Using silicon lubricants.

c)      Reducing ply height.

      9. Avoidance of distortion in the spread:

There should not be unnecessary friction between the bottom of the spread and the surface of the table. To avoid the distortion of a lay, a hard polythene sheet is laid at the bottom of the spread. It helps to avoid disturbing the lowest plies of the material in the spread when base plate of a cutting machine passes underneath. In addition, it prevents snagging of the fabric on the table surface which often becomes roughened with use.

10. Matching checks or stripes:

If the fabric is checked or stripped then it must be laid to the marker plan and they should be matched by the help of needle.

Methods of fabric spreading

Mainly two types:

1. Manual method (Not fulfill the basic requirements)

            a) Fabric is laid completely by hand

            b) With the help of mechanical assistance as hook

c) With the help of the manually operated spreading track

2. Mechanical method (possible to fulfill the basic requirements)

            a) Semi-automatic

            b) Automatic

1. Manual method

            a) Fabric is laid completely by hand:  This method is widely used in our country as

                        i) Simple method

                        ii) Cheap and available worker.

In this method, a roll of fabric is taken and its edge is fixed on one end of the table and then spread on the table without using any device, completely by hand. A large numbers of workers are required to carry out this process.

            b) With the help of mechanical assistance as hook

► The fabric is in roll form may be supported on a frame and carried along the table by hook where the end is secured by a clamp.

► The workers work back from the end aligning the edges and ensuring that there is no tension and no wrinkles.

►The ply is normally cut with hand scissors or a powered circular knife mounted on a frame.

c) With the help of the manually operated spreading track

► The spreading machine carry a piece of fabric roll from end to end of the spread, dispensing one ply at a time on to the spread.

► Their basic elements consists of a frame or carriage, wheels traveling guide rails at the edge of the table, a fabric support and guide rollers to help correct unrolling of the fabric.

► In the simpler versions, the operators clamps the free end of fabric in the line with the end of the spread, pushes the spreader to the other end of the spread, cuts off the ply in the line with that end, clamps the beginning of the next ply, pushes the spreader to the other end and so on……

2. Mechanical method

            a) Semi-automatic

In this method,

►There is a motor to drive the carriage platform on which the operator rides, a ply cutting device with a automatic catcher to hold the end of the ply in place.

► In this method, the spreading machine is driven on roll by a motor and fabric is spread on the table. In this method, spreading machine is running with the help of electrical and mechanical speed.

► An alignment shifter is activated by photo-electric edge guides, a turn able and direct drive on the fabric supports and synchronized with the speed of travel to reduce or eliminate tension in the fabric being spread.

Benefits from this technique are as follows:

      Automatic ply counting arrangement.

      Automatic catcher to hold the ends of the ply.

      Photo electric guide for selvedge alignment.

      Fabric fault detector.

      A platform on which the operator rides.

      Maximum fabric width is 3 m

      Maximum weight of fabric rolls 100 kg.

      Maximum spreading height is 25 cm

      Maximum roll diameter is 50 cm

      Maximum spreading speed is 100m/min (changeable).

      Maximum height of the spread is 25 cm (changeable).

      Fabric checking system is available by photo sensor cell.

      Automatic tensioning device is available.

      Any crease or fold in the fabric is removed by this method.

      Spreading length is maintained automatically as per set length.

      Automatic cutting device is present at the end of the spreading.

Disadvantages:

1.      High maintenance cost.

2.      Initial cost is high.

3.      It required high skilled operator.

            b) Automatic

►The automatic spreading machine is an improved version of semi-automatic machine.

►Spreading is done by robot and micro processor.

Advantages:

Automatic machine provides following benefits in addition to the benefits of semi-automatic machine:

                       

      Numbers of plies to spread may be set automatically.

      During spreading, if fabrics roll is finished, spreading heads turns to the end of the housing end of the table and spreading head takes new fabric rolls and starts spreading with splice/overlapping.

      There is sensor in the spreading head that can detect the fabric faults and can cut the defective area widthwise by the cutting knife. Then it starts spreading overlapping the fabric at the cutting point.

      All types of fabric can be spread by this machine.

Types of fabric packages:

Fabric packages are varying in length, width and make up. The choice of package to be delivered to a cutting room is related to the characteristics of the fabric and method of fabric spreading. The forms of fabric packages which can be used are as follows:

I.                   Open fabric-rolled:

      Most woven fabrics are supplied rolled as a single ply direction on to a disposable, tubular card board core about 7 to 8 cm in diameter.

      The packages are suitable for spreading by both manual and mechanical method.

      When spread by hand this type of fabric rolls often require two spreading operators, one each side of the table.

      Open fabric may varying from less than 75 cm (changeable) wide to over 3 m (changeable), especially with knitted fabric that has been slit.

                    

II.                Tubular knit fabric rolled:

  Commonly used in knit fabric.

  Fabrics are supplied as tubular form.

   Spreading machine is suitable for fabric spreading for tubular fabric.

   Usually used for the manufacturer of garments such as sports, shirts or tee-shirts and in specialized cases the fabric width is that required for the shirt body.

                   

III.             Folded fabric rolled:

This form is traditional with the woolen and woolen mixer fabrics used in tailored garments.

      The fabric is rolled on to a disposable, flat board, approximately a centimeter thick.

      It is not suitable for spreading by machine but its lesser width allows it to be spread manually by one spreader on narrower table.

       With folded fabric the marker contains a half set of patterns since the fabric is spread face to face.

      This form is suitable for woolen and woolen mixer fabric.

IV.              Folded fabric-cuttled:

      This form occurs usually with check fabrics and some tubular knits end aims to avoid the distortions which may ensure from tight to rolling.

The doubled fabric is folded accurately backwards in length of approximately 80 to 90 cm (changeable), the end of the piece being wrapped around the pile of the roll.

V. Hanging fabric package: Some expensive fabrics like velvet may be delivered on specially constructed frames to prevent the fabric from any kind of damage.