Development of an effective cleaning method for metallic parts using microbubbles

In this study, microbubble flotation combined with deionized water was proposed as a novel approach to clean oil-contaminated metallic parts. The characteristics of microbubble such as bubble size distribution and filling/collapsing time describe the cleaning expectations of microbubble in oil removal of metallic parts. The preliminary cleaning performance using microbubble coupled with deionized water removed 60% of oil from contaminated metallic parts. Then, minor modifications on the flotation tank and microbubble inlet position successfully remove 80–90% of oil from metallic parts with an optimum cleaning time of 15 min. The oil removal performance of the newly setup microbubble cleaning is compared with ultrasonic cleaning to evaluate its cleaning efficiency. In terms of energy efficiency, microbubble cleaning consumed less power than ultrasonic cleaning when large volume of metallic parts are introduced to the cleaning system. Hence, this study showed experimental evidence for cleaning metallic parts using microbubble coupled with water as a green cleaning approach.