Ultrasonic Cleaning Equipment in Electronic Assembly
The addition of ultrasonic energy to a cleaning fluid dramatically increases it cleaning power. Ultrasonic creates countless vacuum bubbles within the cleaning fluid that then instantly collapse causing micro-shockwaves. This cavitation effect serves as a scrubbing action but without the abrasion that could be associated with a mechanical process or brush. This cleaning action can be used to penetrate cavities or within tight gaps. Within electronic assembly ultrasonic cleaning equipment is used to clean apertures in SMT stencils, around and under component bodies, through via holes, pick up tips used within placement machines, adhesive needles, probe pins on test fixtures and for softening paste materials prior to use. Ultrasonic transducers can used individually within portable mobile cleaning heads or configured within the process walls of cleaning tanks. Stencil apertures can be cleaned within the printer or off line on a bench using ultrasonic cleaning equipment. An absorbent pad dampened with cleaning fluid is placed within a tray under the stencil. Fluid is applied to the top surface prior to placing the Ultrasonic Head (US) in direct contact with the stencil. After just a few seconds all solder paste or adhesive residues trapped within the aperture walls will be released by the ultrasonic + solvent action. Direct Ultrasonic "On Contact" cleaning is used within automatic stencil cleaning equipment. A wall of Ultrasonic transducers fills the complete stencil area whilst cleaning fluid is pumped between both sides of the stencil. Cleaning cycles are under 2 minutes. Dirty test probes on In - Circuit test machine make contact with the printed circuit board difficult and gives inconsistent results. When cleaning pins with a brush damage can occur and the cleaning method is incomplete. An absorbent pad dampened with solvent positioned over the pins plus the action of a portable ultrasonic transducer will clean the pins perfectly in seconds without any risk of pin movement or damage.
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