Effect of Temperature and Frequency on Removal of Nano-Dimensional Contaminants
|Vetrimurugan1, J. Michael Goodson2, Terry Lim3
Cleaning Development Manager, Crest Ultrasonics, Penang, Malaysia1
CEO, Crest Ultrasonics Corporation, USA2
Executive Vice President (Asia) of Crest Group Inc, Malaysia3
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This study investigates the effect of temperature on removal of sub-micron particles from metal surfaces for various frequencies. The frequency used for this study was 25 kHz, 40 kHz, 58 kHz, 58/132 kHz, 132 kHz, 360 kHz, 470 kHz and 1 MHz. The temperature studied ranging from 30 οC - 70 οC. The parts are washed with various frequencies and temperatures and then the parts are subjected to Liquid Particle Counter (LPC) analysis. The size of the particles reported for this study was >0.2 um counts. The result shows that the particle count decreases with increase of temperature hence higher cleaning efficiency until 50 -60 οC and then the particle count start increases. The removal efficiency for various frequencies increases with increase of temperature until 50 -60 οC and then it start decreases. The effect of temperature on cavitation intensity for various frequencies (measured by ppb probe) was also carried out. The aluminium foil test was also carried out to see the effect of temperature for various frequencies. The result shows that the cavitation intensity decreases with increase of frequency and temperature. The aluminium foil study shows that the erosion rate is high for 30 οC compared to 70 οC. The erosion rate decreases with increase of temperature and also found more uniform dents on the aluminium foil for higher temperature. The result also shows that the erosion rate is high for 25 kHz compared to other frequencies tested. This is due the fact that the energy released during bubble implosion is significantly more for low frequencies compared to higher frequencies.