1 Industry Background
The research is conducted in garment industry whose major products are Men’s formal shirt in various order size. The factory consists of central cutting department, 3 independent stitching lines and central finishing (packing) section. Generally, operators are responsible for the quality of individual work, even after that there is quality check (audit) at the end of each section (department) so that there should not be any defective parts transferred from one section to another section. The overall production flow chart of the shop floor is shown in Figure 3.
Garment manufacturing process consists of series of different steps. These steps are broadly divided into two categories pre-production and production process. The preproduction process consists of designing the garment, pattern design, sample making, production pattern making, grading and marker making. Once the sample is approved for commercial production, final marker is made for cutting. The production process consists of cutting, stitching (preparatory and assembly) and finishing all these process are described here.
1.2.1 Cutting Section
In cutting section fabric rolls are inspected as per work order. These inspected rolls are segregated on two sides as the quality pass and fail. The pass rolls are taken into the next operation whereas the fail
rolls returned to store with red tags on them. After this, depending upon the order, size and quantity ratio; the spreader spreads the fabric for cutting. Once cutting is done, bundles of approx 20 to 30 pieces are made and fusing is done simultaneously. After fusing, all the parts are collected and put in the cutting audit. The bundles which pass the cutting audit are forwarded to the sewing section (i.e.
preparatory section) whereas the fail bundles were re-worked for correction. This whole process can be shown in the flow chart as in Figure 4.
1.2.2 Preparatory Section
In preparatory section individual parts are made for assembly purpose. It consists of
four sub sections Cuff, Collar, Front and Sleeve. Each of these sections includes the
series of different operations to complete that part. These final parts are checked (or
audited) so that defective parts should not go to the assembly operations; the flow of
operations for the preparatory section is shown in Figure 5.
In current situation, the preparatory operations are aligned in a single line in order of operation sequence. There is a continuous long table between the machines which serves the material flow from one operation to another. Once the operator finishes his (her) operation he (she) pushes the WIP to the next operator in the table and this process continues to the end.
1.2.3 Assembly Section
This section consists of ten operations to make one full garment. The machines are kept in single straight line according to the operation sequence. The final garment from last operation is fully checked and corrected immediately for any defects. WIP movement inside the assembly is made by the help of work aids attached with each machine. The operator, after completing his (her) operation forwards the semi finished garments to the next machine with the help of work aids attached to each machine. This process continues to the end of assembly line for each operation. At the same time the required parts from preparatory are carried up to the assembly section manually. The flow chart for the assembly operation is shown in Figure 6.
1.2.4 Finishing Section
Finishing section consists of three major operations: buttoning and thread cleaning, ironing and final packing. But in some garment washing is needed, in this case washing should be done before buttoning to minimize damages in garments for longer washing cycles. In the case company after buttoning there is thread cleaning section followed by ironing, finishing and packing. The operation sequence for finishing section is shown in Figure 7.
1.3 Style Communication
Style communication between different staffs and operators is critical part of garment manufacturing to minimize style related confusion during production. Because the fashion changes so frequently that there may be the need of producing new styles every day, so in this situation if the shop floor people didn't get accurate information for the garment being produced chances of mistakes are high. To minimize difficulties of this kind, there is pre-production meeting between shop floor supervisors, machine technicians and operators. The purpose of this meeting is to communicate about the various requirements of the upcoming style, for example critical operations on the garment, type of machine and machine accessories required, garment specifications, type of seams, target production per day, total order quantity, size ratio etc. In some industries trial production is done for every new style, this helps to minimize the confusion and rejection during bulk production. In this system commercial production starts only after checking the final parameters of trial production. But nowadays, due to very small order quantity (order volume) the trial production may not be feasible for each style. In such case a clear information flow is of great importance.
1.4 Existing Production Layout
Existing layout of the sewing section (preparatory and assembly) is given in Figure 8. In this layout, the individual parts are made in preparatory sections and these parts are then transported manually to the assembly section. In the assembly section, these parts are assembled to shape a final garment. There is quality check at the end of each section to avoid defective parts to the next step. WIP movement in preparatory section is made with the help of the long table along with machines, whereas work aids attached with each machine serves this purpose in the assembly section.
1.5 WIP Movement System
There are different types of WIP movement systems applied in garment manufacturing industries. Some of them are traditional, for example by trolleys or by hand carry. Some advanced factories use the slow motion conveyor to move the parts from one operation to another operation. The conveyor is designed such that it moves according to the operation sequence. In this system, the first operator stitches and puts the part in the conveyor, then the next operator receives that part. He also sews it and puts it in the conveyor. In this way, the unnecessary movement is reduced. This method is generally
suitable for single piece movement. In some industries, the work aids are designed such that the piece moves in forward directions. When the first operator finishes his operation he gives it directly to the next operator with the help of work aids, and this process continues. Thus the selection of the WIP movement method depends upon the design layout, the technological advancement of the industry as well as expertise of the personnel.