The objective of this research was to improve the productivity for the air conditioner unit of for car manufacturers. The target production volume of the air conditioner unit was greater than 46 pieces per hour. The current capacity was insufficient, so the researchers studied the problems using a study of the assembly standard time. The study found the assembly line bottleneck standard time was 1.64 minutes per piece, representing a yield of 36 pieces per hour. The labor productivity was 1.84 pieces per person per hour. The operation two-hand chart and operation area check sheet analysis was applied to find the operations that should be improved because the standard time was over the takt time. After that the Eliminate, Combine, Rearrange, Simplify (ECRS) technique was used to propose a method for process improvement. After improvement, the bottleneck was 1.28 minutes per piece which represented a yield of 46.9 pieces per hour. The labor production rate was equivalent to 2.35 pieces per hour or an increase of 27.1%.
