LEAN-SUSTAINABILITY METHODOLOGY AND MODEL DEVELOPMENT IN BIO-STONE WASHING PROCESS

• Main Author: Syahrin Syah Putri, Alfi
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/72159
• Institution: Institut Teknologi Bandung

Bio-stone washing is a finishing process that is popularly implemented to degrade color and give an abrasive effect to denim fabric. The washing process requires large amounts of materials such as pumice stones, water, and chemicals, which results in waste that is harmful to the environment and employees. The reduction amount of materials can have an impact on decreasing the quality and productivity of process outputs. Therefore, a sustainability approach related to economics, environmental, and social aspects must be combined with a lean approach that is related to productivity and quality aspects. The purpose of this research is to develop a methodology and model that can optimize lean-sustainability aspects of the bio-stone washing process. As a limitation, the optimal solution of this research is an incremental change that is defined by the optimal process parameter. This methodology generally consists of the preparation, measurement, solution search, and improvement design stages. In the preparatory stage, efficiency indicators must be defined to measure lean-sustainability performance along the processes. Next, efficiency level of each process is mapped in the Sustainability Value Stream Mapping. This map can be used to determine critical processes that are defined as the goal of lean-sustainability improvement. Then a solution search is carried out by mapping relevant variables with the lean-sustainability aspect through an axiomatic sustainability approach. After that, the relationship among the variables is searched using the taguchi design and modeled into a linear regression equation. The search for optimal solutions is carried out by considering economic, environmental, technical, and quality aspects. The objective and constraint functions are built into the linear and non-linear programs for the development of the optimization model. The improvement design from this model is the optimal process parameters that are feasible to be applied in the real conditions of the company. The implementation of methodology and model at CV Oshwin Washing aims to minimize the use of pumice stones and water. Based on the analysis, the results showed a reduction: pumice-ratio from 3.13 to 2.08; water-ratio from 12.5 to 10; the percentage of waste from 61.76% to 55.67%; costs from Rp4.224,75 to Rp2.706,45. However, the quality of the product in terms of visual quality weight increased from 2.49 to 3.41 (scale 0 – 4) Overall, the efficiency level of the production process increased by 2.38% but the employee workload decreased by 1.73%. The difference between this research and previous researches is the development of a lean-sustainability mathematical model in the textile industry. Research in the field of textiles, especially process design and optimization, has not been widely studied. This research contributes in the form of methodology and model to optimize the lean-sustainability aspect of the bio-stone washing process in denim. The model built is comprehensive because it combines various multidimensional aspects that are often a problem in today's industry.