Medical Device Link.

QUALITY CONTROL

Megasonic cleaning can remove submicron human protein from materials such as syringe tips and surgical instruments.

Ultrasonic cleaners work by means of cavitation—the formation of short-lived bubbles caused by a pressure decrease in a liquid. Cavitation also occurs when motorboat propellers quickly spin in water, which creates noise and can cause propeller damage and efficiency loss. Ultrasonic cleaning exploits cavitation in a liquid bath to dislodge impurities clinging to components. Ultrasonic systems in the 40-kHz range are routinely used to treat products such as semiconductor wafers. But in much the same way that cavitation can damage propellers, the bubbles produced by the procedure can harm fragile components as it scours them, causing microscopic surface pitting and wear.

Megasonic cleaning, on the other hand, is capable of safely removing molecules such as submicron human proteins without damaging the components being cleaned. Generating frequencies exceeding 1 MHz, “megasonic cleaners do not operate by means of cavitation like ultrasonic cleaners do,” explains Jon Helgeland, director of sales and application engineering at Piezo Technologies (Indianapolis, IN, USA). “They function by creating a zone of streaming fluid very close to the material’s surfaces.” Capable of being aimed and adjusted, the stream safely removes detached particles from submerged products. “Megasonic cleaners disrupt the boundary layer between the surface and the bulk fluid that can tightly bind particles to the surface,” Helgeland explains.

Piezo Technologies’ megasonic cleaning components can be used on the assembly line to clean small devices, surgical instruments, and lab equipment. The firm does not offer stock products but has its engineering staff tailor transducers, piezoelectric ceramics, and other products to meet the needs of specific applications. “For instance, the medical device industry employs our devices to clean syringe tips between dispensing or fluid pickup operations,” Helgeland notes. The firm’s database of past projects provides a base for developing custom products and modular devices.