Saturday, January 13, 2018

Fabric Spreading Process in Apparel Industry

Spreading is the process during which fabric is cut into pieces of a specific length which are then placed on top of each other to form several plies. The length of a ply is determined by the shape, size and the number of the components which are to be cut from it. The number of plies in a spread depends on the number of articles ordered and the technological and technical limitations of the fabric spreading and cutting processes. The pattern and properties of the fabric determine the spreading mode, that is the manner in which plies in a spread should be placed. Fabric spreading may be carried out either manually or by automation. Manual spreading is traditional and has been used since the mass production of garments first began. The automated spreading process has come into wide usage during the last few decades.

Manual Spreading Process:
The manual spreading process is suitable for small scale production. Manual spreading may be used for all kind of fabrics, including those with complex structures and intricate patterns. In large scale production, manual cutting is often used for working with intricately patterned fabrics. The cost of technical equipment is low compared with automated spreading, but the productivity is poor.

manual spreading process
Fig-1: Manual spreading process
During manual spreading two workers move the fabric plies over the spreading table, ensuring the correct placement of each ply. As they do so, they look for faults in the fabric and make the decision to leave them or cut them out. They also count the plies required and cut the fabric at the end of the spread. If the fabric has an intricate pattern, they ensure the pattern matches in all the fabric plies in the spread.

Spreading speed and quality is dependent on the properties of a fabric and the skills and experience of the workers. There is no need for special equipment in manual spreading. All kinds of fabric may be laid but the process is both highly skilled and time consuming. Manual spreading is used in small enterprises or where, in the case of larger enterprises, there is a need to spread fabrics with different kinds of intricate patterns.

Characteristics of the manual spreading process:
The spreading process is carried out on a spreading table with a smooth surface (see Fig-2). The fabric feeder may be fixed on the table, on a wall (at the end of the spreading table) or may be free-standing next to the spreading table. If a lay end cutter is used to cut the laid fabric plies, it is fixed on the spreading table adjacent to the fabric feeder (see Fig-3). The fabric roll is fixed on a feeder axis before the spreading process is started. According to the spreading mode to be performed, the fabric roll is fixed with its face side up or down. The manual spreading process is performed in sequential steps.

Fig-2: Spreading table with a fixed simple fabric feeder
Spreading table equipped with a lay end cutter
Fig-3: Spreading table equipped with a lay end cutter
These are:
  • Marking the spread data;
  • Spreading the fabric plies;
  • Fixing a marker on top of the spread.
Marking of the spread data:
The marker, which is printed on paper, is placed on the spreading table. It is fixed in the required position and the following spread data are marked on the both sides of the table: the beginning and end of a spread, splice marks (places in the spread where the fabric may be cut and laid double to deal with flaws without damaging the cut components) and size change places (marks used in performing step spreads).

Fabric spreading:
At the beginning of the spreading process, an underlay paper ply is laid on the table to ensure easy transfer of the spread along the table during the cutting process. The fabric spreading process is carried out by one/two workers at each side of the spreading table who move the fabric ply to the beginning of a spread. The end of the fabric ply is placed precisely at the beginning of the spread and secured. Returning to the initial position (the place where the fabric roll is fixed) one worker aligns the laid down fabric ply with the edge of the table and the previously spread fabric plies with a permitted variant of +/-0.5 cm. The second worker smoothes the surface of the ply, ensures an even tension in the fabric and prevents creases or folds appearing during the spreading process. The spreading process is repeated until the desired number of fabric plies are laid down.

The optimal length of a manually performed spread is 4-7 m. Short markers may be joined and laid as one spread, forming either a traditional or a step spread. The number of fabric plies in a spread depends on the size of the order, the fabric properties (thickness, slickness, friction between the fabric and a cutting device, etc.) and the technical limits of the manual cutting machines (the stroke size, shape of the blade, etc.). Narrow tubular fabrics and interlinings are spreaded by a single worker.

The fixing of a marker on the top of a spread:
A marker printed on a paper is placed on the top of a prepared spread. Clamps are placed around the edges of the spread to hold it in position. If the marker is printed on the paper with glue on its reverse side, it is lightly fixed to the top ply of the spread by using a special large base iron.

Disadvantages of the manual spreading process:
The spreading speed and quality is largely dependent on the skills and experience of the workers performing the process. Spreading operators have a heavy load during the working day and fatigue may influence both spreading speed and quality. Two operators are involved in manual spreading process whereas the automated process requires only one.

Equipment for manual spreading:
The equipment used in the manual spreading process is simple and comparatively cheap. The main component is a spreading table. Special lay end cutters may be used to increase the productivity of the process. Several other small auxiliary instruments, such as large base irons, pins and clamps may be used in the process.

Automated Spreading Process:
Manual spreading is time and labour intensive. With the development of mass production, the manual spreading process could no longer provide the necessary productivity and the need arose for specialised machines which were capable of carrying out spreading at a much higher speed. The first spreading machines carried a roll of fabric over the table and performed a mechanised spreading process. New systems and techniques have since been developed. Since computer technology has been used to create and store patterns and their markers, spreading processes have become fully automated. Automated spreading systems have significantly increased the productivity of the spreading process but have not altered its main work principles.

Automated spreading process
Fig-4: Automated spreading process
Automated spreading is performed using a special spreading machine which unrolls a roll of fabric along the spreading table, cuts the ply, counts and ensures the correct placement of each ply on the top of another to complete a spread. Spreading can be semi-automated or fully automated.

In a semi-automated spreading process, the operator moves along the spreading table and follows the spreading process. The operator smoothes the surface of the lay, recognises faults in the spread fabric and makes decisions to leave faults in the spread or cut them out. Fully automated spreading is used for high quality, easy spread materials. The operator sets all the necessary parameters (the length of the lay, spreading speed, fabric tension etc.) and lets the machine complete each spread.

The spreading speed is dependent on the properties of a fabric. It is much faster (approx 1.5–3 times) than manual spreading. It is used in medium and large production enterprises, where the volume of production justifies the cost of the equipment and its maintenance.

The automated spreading process may be performed in semi-automated and fully automated ways.

Semi-automated spreading process:
spreading table (walking or riding on a stand panel) and follows the spreading. The operator smooths the surface of the lay, identifies faults in the spread fabric and decides whether to leave faults in the spread or to cut them out. The operator uses a manually operated speed control handle to change the spreading speed and to reduce the speed in problematic areas, or even to stop the spreading process if it is necessary to define the location of a fault and to cut it out. Some machines have three control buttons instead of a speed control handle: forward, reverse and stop. In these machines, the height of the cutting device is also changed manually or by using a special control button.

Fully automated spreading process:
The fully automated spreading process is used for high quality materials which are easily spread. An operator sets the necessary parameters (the length of the lay, the spreading speed, the fabric tension, etc.). The spreading machine automatically performs the following operations: lays the fabric in the required length of the spread, cuts the material at the end of every ply, counts the number of plies and stops after laying the required number of plies.

Comparing manual and automated spreading processes:
The main advantages of the automated spreading process are the capacity to reduce significantly the work load of the spreading operator and to increase productivity. Productivity depends upon several factors: the length of the spread and number of plies within it, the spreading speed (which is dependent on the fabric properties), the spreading mode, the length of the spreading table, the fabric quality, the time needed to cut the fabric ply and to change a fabric roll and the work efficiency of the operator. Automated spreading machines lay long spreads more quickly and to a higher level of quality than is possible by manual spreading. When fabric is spread manually, it may be stretched through pulling (the same problem may appear using spreading machines without movable fabric bars instead of the cradle type of feed systems). Only one operator is employed in performing the automated spreading process. Many of the work steps are carried out automatically (unwinding a fabric, fabric ply cutting, alignment of fabric edges, length and ply counter, etc.).

Comparison of manual and automated spreading processes:
Manual spreading
Automated spreading
Spreading equipment
  • Spreading table
  • Fabric feeder
  • Cutting device
  • Spreading table
  • Spreading machine
Spreading principles
  • Spreading of pre-set number of plies
  • Visual flaw identification by an operator
  • Splicing manually using on the table marked splice marks and printed markers
  • Spreading of pre-set number of plies
  • Visual flaw identification by an operator
  • Splicing using registered data about flaw placements and special software
Spreading method
  • All kind of fabrics – manually
  • High-quality easy spread fabrics – fully automated way
Advantages of the method
  • Ability to spread all kind of materials
  • Low expenses
  • High productivity
  • Only one operator needed
  • Low work load for an operator
Disadvantages of the method
  • Low productivity
  • Two operators needed
  • High work load for an operator
  • High expenses
  • Cannot spread materials with intricate patterns