Improvement of Operational Performance through Value Stream Mapping and Yamazumi Chart: A case of Bangladeshi RMG Industry

Abstract

To secure a competitive position in the global market, the Ready Made Garment (RMG) sector in Bangladesh has been facing various challenges including the improvement of industrial operational performance. Among the various operational issues, balancing the cycle time along the production line is felt to be a common and effective way for enhanced performance. There are numerous exact and approximate methods which have already been proposed and are available in literature for repetitive batch production. Unfortunately such approaches are rarely applied in the real RMG shop floor presumably due to the enormous efforts needed to align with the frequent changes of product lines. Compared to the exact and approximate methods, adoption of lean tools like VSM and Yamazumi chart is highly acclaimed for their simpler and wider applicability with superior capability in addressing and solving the balancing problems. So for balancing purposes of the RMG shop floor an attempt is made to frame and apply an integrated model combining the VSM and Yamazumi chart as presented in this article. Depending on the theoretical framework, operational performance of an RMG shop floor is evaluated upon balancing the cycle time. In doing so, firstly a current state map (CSM) and the corresponding Yamazumi chart are plotted to comprehend the existing operational procedure and analyse the workstation cycle time with respect to the takt time. Using the Yamazumi chart, the workstations are reorganized to reduce or eliminate the non-value added activities, to introduce parallel workstations, and to merge workstations so that a balanced production line is attained. Performance is then assessed by means of Overall Effectiveness of Equipment (OEE), Capacity Utilization and Efficiency. The results as obtained through testing a real life case study of RMG industry, ensure the effectiveness of the integrated system of VSM and Yamazumi chart to identify the wastes, restore the line balance and improve operational performance.

Improvement of garment assembly line efficiency using line balancing technique

“…Nabi et al 4 on the other hand undertook a time study to determine the standard minute value (SMV), which was subsequently used to eliminate bottlenecks, reduce idle time, and improve efficiency. At present, line balancing techniques have received much attention than other line efficiency and process improvement techniques 23 such as lean manufacturing (VSM), [32][33][34][35] Lean-six sigma, 36,37 Six sigma, 38 and hybrid approach (lean manufacturing and line balancing). 39 Line balancing techniques involve several constraints that have to be put into consideration for example task assignment, task precedence, cycle time, and resource constraints.…”

“…As shown, 65 trouser assembly line tasks were assigned in 39 workstations with total workstations time of 41.763 minutes and total idle time of 33.117 minutes. The idle time for workstations number 5,6,8,10,19,21,24,26,27,28,29,33,34,36,37,38, and 39 remained very high because of the restrictions on the resource (machine type and helpers) and the precedence relations. The precedence diagram illustrating the relations between 65 tasks in 39 workstations was presented as shown in Figure 5.…”

Redesigning and optimizing an electronic device assembly cell through lean manufacturing tools and kaizen philosophy: an application case study

“…The visualizing process supports strategic planning and continuous improvement efforts by providing a comprehensive overview of the entire workflow. Value Stream Mapping (VSM) and the Yamazumi chart are widely praised lean tools for their simplicity and broad applicability as they offer superior capabilities in effectively addressing and resolving line-balancing issues (Kays et al, 2019). Rother and Shook (2003) introduced the Value Stream Mapping (VSM) technique in their book "Learning to See: Value-stream mapping to add value and eliminate muda" as a method for process improvement (Shou et al, 2017) and for organizations embarking on a lean journey, value stream mapping stands out as a formidable tool for planning, implementing, and continually improving their processes (Manos, 2006).…”

“…It involves mapping the entire value stream, collecting relevant data, and identifying waste. The current state map exhibits all the process flows stepwise, by which it is possible to understand what necessary action has to be taken to improve the process (Kays et al, 2019). The future state VSM, on the other hand, envisions an Redesigning electronic device assembly cell improved and more efficient process after implementing changes.…”

“…The visualizing process supports strategic planning and continuous improvement efforts by providing a comprehensive overview of the entire workflow. Value Stream Mapping (VSM) and the Yamazumi chart are widely praised lean tools for their simplicity and broad applicability as they offer superior capabilities in effectively addressing and resolving line-balancing issues (Kays et al ., 2019).…”