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A suitable shape of the suction head for a cleaning process in a factory developed by computational fluid dynamics
(2021-11-01)
Thongsri, Jatuporn
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Tangsopa, Worapol
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Khongsin, Jirawat
The previous shape of the suction head (SH) employed in a cleaning process in a factory had a low performance, removed fewer particles, and generated an annoying noise. Therefore, new shapes of SH have been proposed to solve the issues and the cleaning performance was investigated by the Shear Stress Transport (SST) k-ω turbulence, Discrete Phase (DP), Large Eddy Simulation (LES), and Ffowcs Williams and Hawkings (FW–H) models in a transient state of computational fluid dynamics (CFD). The SST k-ω and DP models were applied to determine the airflow, suspension velocity, cleaning region, and particle trace. In addition, the LES and FW–H models were used to evaluate the noise, sound pressure level, and frequency generated from the proposed shapes. All simulation results were validated with the air velocity and noise measurements and were analyzed to find a suitable shape. The simulation and experimental results revealed that the shapes of the SH affected the cleaning performance and noise generation. The higher the air velocity, the higher the noise generation. The suitable shape delivered a 4.37% better particle removing performance and 11.1 dB less noise generation than the previous shape. The outcomes of this research are the suitable shape of the SH and the research methodology which enabled the application of both CFD and experiments to solve the issue to help enhance the efficiency of the cleaning process in an actual factory.
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Evaluation and improvement of ventilation systemreduceinside low-costparticle contaminationautomation line to
(2020-02-28)
Puangburee, Lamai
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Busayaporn, Wutthikrai
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Kaewbumrung, Mongkol
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Thongsri, Jatuporn
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 ve-locity 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 momen-tum source (S<inf>m</inf>) and/or redesigning the LCA’s model especially extending its height of cover. The increasing of S<inf>m</inf> can be simply implemented by increasing the air-condition power to the optimal values accord-ing to the calculation leading to a reduction in recir-culation 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.
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Numerical investigation on the performance of suction head in a cleaning process of hard disk drive factory
(2020-02-28)
Khongsin, Jirawat
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Thongsri, Jatuporn
The suction head is a component positioned at the vacuum cleaner’s tip and used to control airflow to eliminate small particles, thus preventing contamination from occurring during the cleaning process at a hard disk drive (HDD) manufacturing factory. At the factory, 2 suction head types (bowl and straight) were used in the cleaning process. From an actual usage, the operators questioned the operating condi-tion’s performance and suitability. In order to seek an answer to the questions, the researchers used computational fluid dynamics (CFD) to simulate airflow and particle trace using the ANSYS Fluent software, the factory’s actual conditions, and a suction distance ranging between 2.5–15 mm. CFD simulation results showed that the bowl type suction head performed better compared to the straight type in every suction range under the exact same operating conditions. Both suction heads performed well at a 5 mm distance between the suction head and cleaning area. Suction performance decreased when the head was positioned closer or farther than the mentioned distance. Apart from applying all results from this research to increase cleaning efficiency in the actual factory, the findings could also be used as basic information for designing new suction head models with higher efficiency than the original model.
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A CFD investigation of airflow in a hard disk drive production line to detect the cause(s) of contamination and its mitigation
(2017-07-02)
Khaokom, Adisorn
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Thongsri, Jatuporn
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Kaewkhaw, Polsate
Contamination exceeds the standards in certain areas within the production line of hard disk drive (HDD) manufacturing, such as in the clean room of a factory. In order to find the cause(s) and solve the problem, we decided to use the computational fluid dynamics (CFD) to simulate the airflow within the production line. The results show the cause of contamination, which is from the exhaust fan installed in the electrical testing machine in the production line of HDD manufacturing, which releases large amounts of particles. To resolve this problem, the CFD results were analyzed to design and create a new cover for the exhaust fan. Once this invention is installed to the electrical testing machine, it can control the airflow to float into other areas that do not affect nor contaminate the product. The factory utilized this research. Other than solving contamination problems that exceed standards, it also saves production costs from purchasing new machines as well.
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A Successful CFD-Based Solution to a Water Condensation Problem in a Hard Disk Drive Factory
(2017-01-01)
Thongsri, Jatuporn
This paper was intended as an article of a practical solution. The settings of a ventilation system for a production line in a hard disk drive (HDD) factory were inappropriate leading to a condensation problem in a work area causing the finished products to be defective and unsalable. This paper describes an attempt to solve this problem and the outcome. Computational fluid dynamics (CFD) was used to simulate the airflow from a ventilation system in an HDD factory. The simulation results were validated with actual values measured with instruments readily available at the factory. The simulation results showed that the airflow patterns and temperature distribution of the air above and around some areas in the production line were not proper. The old temperature setting of the system for the air coming out of the inlet caused the temperature of the air above the said areas to be in the range of 13-20.5 °C, which was lower than the dew point temperature thus causing a condensation problem. From the results of the simulation, we recommended the factory to increase the inlet air temperature to be around 16.5-22 °C, so that the temperature of the air above and around the work areas would be higher than the dew point temperature and more uniform. The factory implemented our recommendation and found that it not only solved the problem satisfactorily but also saved the air-conditioning cost.
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Optimum airflow to reduce particle contamination inside welding automation machine of hard disk drive production line
(2015-03-01)
Thongsri, Jatuporn
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Pimsarn, Monsak
Welding automation machine (WAM), used for welding minute components to the head gimbal assembly (HGA) of a hard disk drive (HDD), needs to operate in a strictly clean environment. In today’s HDD factories, to prevent airborne particle contamination to the WAM, Fan Filter Units (FFUs) are installed on top of it to supply clean air and blow away outside airborne micro particles, keeping the microenvironment clean. Furthermore, the mass of the clean air should also carry away harmful particles generated inside the microenvironment. In this research, numerical simulation of airflow inside a WAM was performed in order to verify these cleaning functions of the airflow. A transition shear stress transport turbulence model was employed to simulate airflow from the FFUs through and out of the microenvironment. The simulation results showed that the airflow from the FFUs truly performs the two cleaning functions as intended. Moreover, they also revealed that the optimum air speed, the speed resulting in the lowest particle counts, is in the range of 0.35–0.55 m/s. Our findings can be useful for developers who may use FFUs to reduce particle counts in the environment of other types of industrial machinery.
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Simulated trajectories of particles and the number of particles trapped by the circulating filter in a hard disk drive
(2014-01-01)
Thongsri, Jatuporn
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Pongkom, Vana
The particle trajectories and the number of them trapped by circulating filter of a 2.5 inch dual platter hard disk drive (HDD) were numerically investigated using a transition shear stress transport turbulence model (transition SST). Four head gimbal assemblies (HGAs) were placed at the outer diameter positions where tiny particles of alumina were released. The simulation revealed the results of airflow, particle trajectories and efficiency of a circulating filter. This result can be applied as fundamental information to design HDD layout in order to reduce its contamination. © (2014) Trans Tech Publications, Switzerland.
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Successful simulation of airflow in the microenvironment of an assembly automation machine and its implication
(2014-01-01)
Thongsri, Jatuporn
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Khaokom, Adisorn
Today, the hard disk drive (HDD) industry is using assembly automation machine (AAM) to construct head stack assembly (HSA) from smaller parts. AAM needs to operate in a clean environment with very low particle counts. To achieve this end, fan filter Unit (FFU) is used to supply purified air into the environment by filtering out airborne particles from recirculating air. In this study, we investigated numerically the airflow induced by FFUs inside a microenvironment that houses an AAM in an HDD factory. The boundary conditions chosen for simulation were directly derived from the real ambient conditions in this HDD factory. We found that the FFUs not only filter out airborne particles from the air supplied into the microenvironment but also act as a particle blocker, pushing away the nearby particles in the air surrounding the openings of the microenvironment. The findings from this study can be applied to cases where other kinds of machinery need to be protected from airborne particles. © (2014) Trans Tech Publications, Switzerland.
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Numerical investigation of airflow pattern inside environmental chamber
(2014-01-01)
Thongsri, Jatuporn
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Suksawaeng, Wutthinan
In industrial hard disk drive research and development laboratories, an environmental chamber is normally used to perform a mechanical verification test of Head Gimbal Assembly (HGA). It is very important to verify that the airflow pattern in the chamber is comparable to that in a real hard disk drive. Hence, we applied a transition shear stress transportation turbulence model (transition SST), one of the robust mathematical models in computer fluid dynamics, to simulate the airflow behavior inside both an environmental chamber and a hard disk drive (HDD). We found that, overall, the two patterns of airflow were not comparable at all. The air velocity vectors around the HGA in VENA were smaller than that in HDD. The reason for this is likely to be that there was more space between the top cover of the chamber and the platter than the space between the top cover of the hard disk drive and its platter. © (2014) Trans Tech Publications, Switzerland.
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A simulation of the number of particles trapped by the circulating filter of a hard disk drive and their trajectories
(2014-01-01)
Thongsri, Jatuporn
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Pongkom, Vana
A transition shear stress transport turbulence model and a discrete phase model of Fluent software were employed to simulate numerically the trajectories of loose particles and the number of them trapped by the circulating filter of a hard disk drive (HDD). The filter was located either at the left or the right of a 2.5 inch dual platter HDD rotating at 7200 rpm. Particles were released from the middle diameter position where four head gimbal assemblies (HGAs) were located. The simulation included airflow and particle trajectories released from any of the four HGAs. The results of this simulation can help determine the efficiency of a circulating filter and its optimal placement. © (2014) Trans Tech Publications, Switzerland.

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