Process and properties of micro-ultrasonic powder molding with polypropylene

Ultrasonic Molding Technology: Recent Advances and Potential Applications in the Medical Industry

“…The research works of Fairbanks [10], Paul and Crawford [11], Matsuoka [12], Kellomäki and Törmälä [9], Liang et al [13] and Zeng et al [14] were identified as ultrasonic compression molding. In all of them, the raw material is directly poured into the mold cavity, compacted by the sonotrode, and plasticized by ultrasonic energy inside the mold cavity.…”

“…Ultrasonic compression molding is a manufacturing process where polymeric powders are ultrasonically plasticized and shaped by the action of compressive forces inside a mold cavity. In UCM of small parts, the polymer is rapidly plasticized and fills the mold cavity reducing problems of insufficient filling and welding marks [14]. Moreover, UCM is capable of processing polymeric and eutectic alloy powders [24] in a relatively short time cycle (usually less than 10 s).…”

“…They fabricated ultra-high-molecular-weight polyethylene (UHWPE) column micro-arrays, achieving good replication results reaching up to 91.9% replication rates of a micro-column of 117.3 µm of diameter. Examples of other geometric shapes recently produced are micro-dual gears of ethylene vinyl acetate with pitch diameters of 1 and 1.8 mm respectively with a 60 µm thickness [13] and polypropylene gears with pitch diameters of 4.8 mm with a 1 mm thickness [14]. Currently, this technology is focused on manufacturing micro-parts, leaving behind its application in the fabrication of macro size parts.…”

“…According to K. Zeng et al [14] the understanding of the temperature distribution phenomenon in UCM is essential for processing homogenous and degradation-free polymeric parts. During the UCM, the heat generated by the compressive forces among the powder particles and the ultrasonic energy transmitted to the polymer increases the temperature that melts the powder particles.…”

Micro-ultrasonic powder moulding of Sn–Bi/Cu composite micro parts in semisolid form

“…Fairbanks (1974) introduced ultrasonic wave techniques into the moulded formation of a polymer powder; the polymer was processed without external heating and melted with the thermal energy resulting from the friction between the grains which caused by ultrasonic vibration. Zeng et al (2014) proposed micro-ultrasonic powder moulding (micro-UPM) and successfully fabricated micro parts using isotactic polypropylene powder. Micro-UPM is characterised by a short forming period and low energy consumption, which is suitable for forming various polymer powders.…”