A Low-Cost Automation (LCA) line, a group of machines to manufacture hard disk drive's components located inside a clean room of factory, faces the problem of particle contamination caused by an improper ventilation system. To solve this problem, Computational Fluid Dynamics (CFD) has been implemented to evaluate airflow and simulate solutions to improve the ventilation system of the LCA. By using actual operating conditions collected at the factory and Fluent CFD software, the simulation showed that airflow patterns in such areas were substandard. For example, the large areas of recirculation zone with air velocities lower than 0.2 m/s such as Fan Filter Units' conveyor and Work Area. The low velocity of the airflow can cause particle contamination and leads to low-quality production. To reduce the particle contamination, we suggested novel solutions based on the CFD results by increasing the momentum source (S m ) and/or redesigning the LCA's model especially extending its height of cover. The increasing of S m can be simply implemented by increasing the air-condition power to the optimal values according to the calculation leading to a reduction in recirculation areas. In addition, extending the height of the LCA's cover also improved the air velocities in the critical areas to meet the factory's standard.