An analysis of a production process, undertaken as part of a case study, revealed that a company was unable to meet its expected production capacity during the assembly process of wheelchairs. A deviation of 53% from the current production capacity resulted in a delay in product delivery. This investigation revealed that the company's calculation formula was not aligned with the current working condition, leading to extremely imprecise estimations of the production capacity and cycle time, due to the variations in the parts needed for each wheelchair model. To address this issue, this study centered on the Model A wheelchair, which shared 80% of its components with other models, as a benchmark for analyzing the standard assembly time and identifying key parameters. Simulation tools were also applied to support improvements, as bottlenecks and imbalances were observed in the production line. In this research, ECRS principles were applied to tackle these inefficiencies, resulting in a notable increase in production capacity from 35 to 46 wheelchairs per hour, representing an additional 143,000 baht per hour in revenue. The cycle time at Workstation 4 was reduced from 100.53 s to 60.41 s, while the production line efficiency rose from 64.70% to 107.65%, giving a 42.95% reduction in waste. A comparison between the actual system and the simulation indicated a minor difference in production capacity per hour, with a deviation of only 1.57%, consistent with the initial hypothesis.