Experimental Study and improving the productivity of Assembly line Balancing in Teleja Garment Manufacturing in Ethiopia

This study is designed to assess and improve apparel sewing section efficiency and productivity throughout line balancing. Apparel industry is one of the oldest and among the most global industry, being primarily concerned with the design and production of cloth and their supply. The central process in apparel manufacturing is the joining together of components which is known as the sewing process , which is the most labour intensive type of manufacturing process .Proper utilization of resources in garment sewing section is more critical to enhance the performance of the apparel industry by reducing production cost and minimizing wastage. For effective utilization of resources in the sewing section, good line balancing is important to increase productivity and production efficiency. This research was a design to analyse and improve the assembling line in the case of Telaje garment manufacturing and sales plc. The study was first conduct observations in the production floor and start work with the selection of sewing line in the garment production process. Among the nine lines of the factory select one on the production floor and one garment ordered product known as five pocket men’s jeans trousers are selected. For this study, both qualitative and quantitative research approaches were employed. Both primary and secondary data sources are used to detail the collected relevant data to understand the current efficiency scenario of the factory. The main challenges to minimizing line efficiency and productivity with the expected performance measurement are improper utilization of resources and improper implementation of line balancing in sewing section, therefore this thesis work shows that the bottleneck process and consequence solution will be searched, and finally significantly improving the productivity by 418 unit products/ day and, hence the efficiency will increase from 28.83% to 50.04% of the line. Key words; Assembly line, Bottleneck, Line balancing, Productivity

which is assigned to a set of workstations linked together by a transport mechanism under detailed assembling sequences specifying how the assembling process flows from one station to another [19] .In assembly line balancing, the 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 labour. Division of labour should be balanced equally by ensuring the time spent at each station is approximately the same. Each individual step in the assembly of the product has to be analysed carefully and allocated to stations in a balanced way over the available workstations. Each operator then carries out the operations properly and the work flow is synchronized [15,21]. Manufacturing a product in an assembly line requires partitioning the total amount of work into a set of elementary operations called tasks. Tasks are assigned to operators depending on the constrains of different labour skill levels. Assembly lines have been widely used in various production systems to produce high volume standardized products. An assembly line includes a series of stations arranged along a material handling system.
The components are processed depending on a set of tasks for a given cycle time. Tasks are assigned to an ordered sequence of stations according to a given precedence relationship among them. The problem of assigning tasks to stations to optimize a specific objective, such as minimizing the number of stations for a given cycle time, minimizing the cycle time for a given number of stations, or maximizing the efficiency of an assembly lines, subject to the precedence relationships among tasks, is called the assembly line balancing (ALB) problem. Multi-manned assembly line balancing problems (MALBP) are a new type of generalized assembly line balancing problems in which there is the possibility of assigning more than one operator to each work station according to the product features [12,14]]. These types of balancing problems typically occur in industries with high volumes of products. In this type of assembly line, in each workstation, instead of one worker, several workers simultaneously perform different operations on the same individual product. The main goal of using this kind of multimanned workstations is to minimize the number of workstations in the line while the total effectiveness of the line (in terms of the number of workers) remains optimal. In this work, the asses' assembly line balancing of the sewing sections to enhance the productivity and efficiency of the company

METHODS:
This research was designed to analyse and enhance the assembling lines in the case of Telaje garment Manufacturing and sales Plc. The study was first conducted through observation starting from the production floor. Selection of sewing lines and ordered products are made. Then the experimental work is performed and then analysed. Based on the results obtained, the way for improving asseTelaje garment production will be proposed. Both qualitative and quantitative approach methods were used. Collected data were analysed using descriptive statistics for analysis. The obtained results were presented using numerical value and the graph

Data collection
The data were collected from Telaje Garment Manufacturing and Sales plc. in the garment sewing section .Both primary and secondary data sources were used to collect relevant data. Primary data was collected from direct observation from the production floors and interviews with the line supervisors and other responsible persons.
The data mainly focused on one type of product within the assembling line knows as five pocket men Jeans Trousers. Secondary data were collected through reviewing related literature, different books and journals and different legal documents. For the effectiveness of this study, some garment sewing section line balancing calculations including work study, time study, and SMV were used.

Data analysis
For this study, among nine lines of the factory, one line on the production floor, and one garment ordered product which is known as five pocket men's jeans trousers are selected. For the selected product, perform an operation breakdown based on their style and operational sequences before doing line balance. Working out a performance breakdown to compare the current factory method and the possible standard methods. Examine work measurement to establish the time for a qualified worker to carry out a specified job at a defined level of performance, and collecting and recording the time studies to systematic recording and critical examination of existing & proposed ways of doing work. Further Calculation was made for SMV & Efficiency to know the time required to complete one piece of garment by a qualified (standard) operator at standard condition. Finally, for smooth production flow, improved efficiency and productivity, appropriate and a balance line will be proposed with modified layout based on.

RESULTS AND DISCUSSION
For this thesis work the researcher interpret and analysis three main data, first analysis current company used data as it is, this data was directly collected from the company .secondly analysis current factory performance study by the researcher who record observing time to analysis correctly for method study and time study to the current garment assembly line in sewing section, thirdly critically analysis assembly line balance of the factory and implemented finding solutions on the assembly line balancing of Telaje garment and sales plc., Based on the two data reduce drawback of the existing scenario and implementation proposed solutions to enhance productivity and efficiency.  Pitch time is used for line setting and calculating the production targets for the line.
A graphical presentation of individual operation's time and pitch time on the same chart is called pitch diagram.
In this chart on X-axis operation the assigned name and on Y-axis the time value is depicted. First, conduct a capacity study for all operators and determine how many pieces the operators are making at each operation.
Where more than one operator is doing the same operation, sum up their capacity for that particular operation.
Based on this information, the calculated existing scenario of pitch time is mandatory for assembly line balancing.   As comparing the existing scenario and proposed data based on rate, basic time, SAM value target and total capacity are analysis as follows. In existing scenario it gives 90% of rating but based upon operator experience, Fluid motions, coordination and wasted actions this data is more exaggerated so that proposed rating is 80%  Not any operators were doing the jobs more promptly than the requirement. So this indicates the line was imbalance. work load is excess that was distributed among the higher capacity possessing workers considering the layout. Thus the bottlenecks were solved and maximum capacity was utilized and most importantly productivity was improved. Finally minimize thus bottleneck process and increasing line productivity and total line efficiency enhancing up to 50.04%.
Proposed line Operational procedure for selected style

Production Cost for five pocket trousers
In the daily production report, many companies include the actual garment production costs of the style. In this study, the production cost represents the sewing room cost and is taken to identify the cost of each situation. .Actual garment production cost of five pocket trousers is sum of the cost incurred for direct and indirect cost

CONCLUSION
The objective of this thesis was to improve the productivity of the manual single model assembly line. Line balancing concept was applied to a case study problem and four different assembly solutions were developed and 29.1% to 50.04%,productiveity from 184 pieces/day to 387 pieces/day and production cost was minimize from 32.796 cost per pieces( ET birr) to16.72 cost per pieces( ET birr).Therefore this thesis work improved assembly line in all aspects especially productivity and efficiency of the company.

Authors' Contributions
Yohannes Admassu researched the data, undertook data processing, contributed to data analysis, interpretation, and preparation of the manuscript. Contributed to the direction of the study, supervised data acquisition, reviewed, and revised the manuscript.