Abstract:
The manufacturer of the motorcycle factory is the case study of this research. In the
conventional production, it took 256.07 seconds for one piece or 197 pieces per day for one machine. Which is not enough for the current demand of 230 pieces per day for one machine.
Therefore, this research objective is to improve the process of motorcycle tire production to be
more efficient. Firstly, the tire production process was studied, there were a total of 4 workstations.
The second workstation and the fourth workstation (the shaping station) are the bottleneck stations.
After that, the sub-tasks in bottleneck workstations were taken into account. There were 3 sub-tasks
that consumed time: 1) Wrapping the steel structure (JLB), 2) Rolling the steel structure on the
tread, and 3) Assembly the 1st product with the 2nd product. They took an average time of 42
seconds, 40 seconds and 43.51 seconds respectively. The why-why principle was applied together
with decision trees to analyze causes and solutions. The causes and solutions of 3 sub-tasks
following these; 1) Too low speed of wrapping the steel structure is the cause of wrapping the steel
structure (JLB) sub-task. Increasing the speed as high as possible but not breaking the steel structure
has been corrected. The new process takes 28.79 seconds. 2) Rolling the steel structure on the tread
caused by rolling the tire is too wide. Corrected by reducing the distance of rolling the steel structure
and the tread from 55 degrees to 30 degrees, reducing the time to 15.77 seconds. And 3) Assembling
the 1st product and the 2nd product caused by the speed of roller movement being too slow. Fixed
by increasing the speed of the assembly roller, reducing the time to 36.83 seconds. After making
productivity improvements to all 3 sub-tasks, it was found that the total production time of
motorcycle tires was 211.95 seconds per tire per machine, or decreased by 18%, resulting in a yield
of 238 tires per day per machine.