The expanding manufacturing sector of plastic items is coming about because of the injection molding process and the quick advancement of existing innovation. One of the most time-consuming, non-value-added tasks in a manufacturing process is setup, or changeover. The study was conducted at a plastic product manufacturing company in Bangladesh. This study's goal was to demonstrate how changeover time reduction approaches may be used in a medium-sized production facility to cut down on total process lead time with the assistance of lean manufacturing tools. The analysis of numerous factors, including non-conformities, complaints, and delivery delays, revealed improvement prospects. In this research, three cases were considered for reducing overall changeover time: one is Reduce 7 Wastes (Case 1), the second is Improve SMED with 5S and 7 Wastes (Case 2), and the third is Total Change Over Works, which can be classified into external and internal works (Case 3). After implementing improvement measures, changeover time was reduced by 18%–33%. The most essentially decreased changeover time was 33% compared to the result for case 2, and they improved their main manufacturing line's output capacity by 10% by focusing on lean tools (5S, SMED, 7 waste). The company was able to avoid using temporary workers due to this development since it allowed employees to work longer hours during peak times. The study also explores how these techniques may be used in other major manufacturing industries that engage in mass production at several worldwide locations, in addition to a medium-sized facility.The expanding manufacturing sector of plastic items is coming about because of the injection molding process and the quick advancement of existing innovation. One of the most time-consuming, non-value-added tasks in a manufacturing process is setup, or changeover. The study was conducted at a plastic product manufacturing company in Bangladesh. This study's goal was to demonstrate how changeover time reduction approaches may be used in a medium-sized production facility to cut down on total process lead time with the assistance of lean manufacturing tools. The analysis of numerous factors, including non-conformities, complaints, and delivery delays, revealed improvement prospects. In this research, three cases were considered for reducing overall changeover time: one is Reduce 7 Wastes (Case 1), the second is Improve SMED with 5S and 7 Wastes (Case 2), and the third is Total Change Over Works, which can be classified into external and internal works (Case 3). After implementing improvement measures, changeover time was reduced by 18%–33%. The most essentially decreased changeover time was 33% compared to the result for case 2, and they improved their main manufacturing line's output capacity by 10% by focusing on lean tools (5S, SMED, 7 waste). The company was able to avoid using temporary workers due to this development since it allowed employees to work longer hours during peak times. The study also explores how these techniques may be used in other major manufacturing industries that engage in mass production at several worldwide locations, in addition to a medium-sized facility.