he ready-made garment (RMG) sector is the lifeblood of Bangladesh economy achieving higher export growth every year. The sector is now the largest contributor not only to overseas trade but also to the national economy. Bangladesh textiles and RMG industry comprises 1,55,557units -1,48,000 handlooms units, 3,284 mechanized primary textile units, 5150 export-oriented readymade garments manufacturing units and 273 garments washing-dyeing units. The sector is a major foreign exchange earner for Bangladesh contributing 77 percent to the country's net T Baggies, Bermuda shorts, Boardshorts, Boxer shorts, Cargo shorts, Jorts, Cut-offs short etc. are used by men. Women use Boyshorts, Bun huggers, Culottes, Daisy Dukes, Dolphin shorts, Hotpants, Short shorts, Skorts etc. most [5].

To make shorts industrially about 44 operations are needed. Some of these are performed by helper manually and rest of operations is completed by the operator with help of machine.

Assembly Lines are used in high production situations where the work to be performed can be divided into small tasks and tasks assigned to the workstations on the line. Key advantage of using manual assembly line is specialization of labor. By giving each worker a limited set of tasks to do repeatedly [6].

A standard method is needed to get the maximum productivity by using the assigned time properly. The job is broken down into parts and the parts are timed. The parts are known as Element. Contents of each element should be homogeneous as possible. If the element is shorter, two or more should be combined into one [7]. In assembly line balancing, allocation of jobs to machines is based on the objective of minimizing the workflow among the operators, reducing the throughput time as well as the work in progress and thus increasing the productivity. Sharing a job of work between several people is called division of labor. Division of labor should be balanced equally by ensuring the time spent at each station approximately the same. Each individual step in the assembly of product has to be analyzed carefully, and allocated to stations in a balanced way over the available workstations. Each operator then carries out operations properly and the work flow is synchronized. In a detailed work flow, synchronized line includes short distances between stations, low volume of work in process, precise of planning of production times, and predictable production quantity [8].

Standard minute value is the standard time, to complete any given task by using best possible methods at standard level of performance. To estimate SMV we have to analyze the garment carefully and check different factors that affect the SMV. SMV of a product varies according to the work content or simply according to number of operations, length of seams, fabric types, stitching accuracy needed, sewing technology to be used etc.

Standard minutes (SMV) of few basic products have been listed down with its SMV range according to work content variation [9].

Breakdown is a listing of the content of a job by elements. A garment consists of some parts& some group of operations. Breakdown means to writing down all parts & all process/operation after one another lying with the complete garment according to process sequence. It is a must to write down the estimated SMV & type of machine beside each &every process [10].

Work study is a generic term for method study and work measurement which are used in the Examination of human work in all its contexts and which lead systematically to the Investigation of all the factors which affect the efficiency and economy of the situation being reviewed, in order to effect improvement [11].

Therefore, garment production needs properly rationalized manufacturing technology, management and planning [12]. Performance rating is the process during which the time study engineer compares the performance of the operator under observation with his own concept of normal performance. The concept of normal performance must be such that the time standards set from it and must be within the capacity of the majority of workers in the enterprise [13].

Line balancing is the allocation of sewing machine according to style and design of garment. It depends of that what type of garment we have to produce [14].

An experimental investigation for the distribution of SMV for each and every operation require for making a men's and provides a clear and details concepts for determining line balancing, machine requirements, man power allocation for setting a definite target within a reasonable efficiency.

The main objective of this study is to form a sequential list of all the elements (operation breakdown) in sewing line involving with producing double layer shorts as well as distributing Standard minute value for every element (tasks) of this job. Besides, following issues are concerned: To draw a clear job flow chart of making shorts, to determine the manpower and machine allocation, to define a way to minimize SMV and maximize productivity and to set up a balanced sewing line practically.

A study was carried out in the garments Industry named Ehsan Garments Ltd. Located at Tongi, Gazipur, Dhaka, Bangladesh and Moonlight Garments Ltd. Located at Tongi, Gazipur, Dhaka, Bangladesh. We attempted this study for proper utilization of man and machine.

Generally, two different types of fabric are used for double layer shorts. For our study we took 100% polyester single jersey fabric (width-58-60", weight-120gsm, technique-knitted) as lining fabric and ricehole mesh fabric (width58-60", 140gsm, warp knitted) as shell (outer) portion. As such type of shorts is used as nightwear, ready for the gym, walking fit wear, athletic fit The investigation occurred for M size garments consisting with 32-34" waist and 8" inseam. Calculated Production/Hour @ target efficiency = 60/Operation SMV @ target Efficiency Calculated Machine number = (SMV @ target efficiency * Hourly production target/60) ? Last of all a table form summary of required number of machine was drawn to achieve hourly production target.

In order to balance the sewing line as well as to increase the efficiency of the line, at first a detailed work and time study was carried out to find the task durations.

However, the time required to complete a task depends on a lot of factors such as the task, the operator, the properties of fabric and sub materials, working environment, quality level of the product, the hour of the day, psychology of the operator etc.

The following table denotes the operations breakdown (elements) sheet and number of required machines.

Line balancing is the allocation of sewing machine according to style and design of garment. Line balancing Chart is such type of tool that indicates how a sewing line balanced. It describes every workstation and required time for completing individual task in sequence with the cooperation of Basic pitch Time (BPT).

The line balanced according to our calculated SMV for the double layer men's shorts we found the following Line Balancing Chart:

The time consumption of every workstation is nearly about to BPT and that means the chances of bottleneck are reduced.

During our investigation, we found few hours that failed to achieve our estimated target and bottleneck has risen up. The reason of this problem was listed out in bellow:

V.

This study on operation break down and SMV distribution of men's shorts is on the basis of time study for bulk production in industry. It is very important and critical task in an apparel production industry. In practice we may use more or less machines, man power, raw materials and other resources for want of proper balance of tasks and as well as the prior precise apparel industry. Thus it would reduce the all kinds of wastes and consume least resources i.e. man, machine, materials, money, etc. It will definitely help us to come the main goal of an industry that is making maximum profit.

By this study, we have described the whole job of making double layer short broken down into elements. This study was going on with experienced and non-experienced machine operators and helpers. The environment kept in standard for Bangladesh. It is suggested that to get better productivity all the people involved with production should be experienced and standard environment of workstations should maintain properly. According to our elements (operation) bulletin we also designed a line layout concerned with the SMVs sheet that taken by direct time study. Line balancing chart indicates succeed of the established line.

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