label: PCB Cleaner,printed circuit boards,PCB manufacturer
Newly manufactured printed circuit boards (PCBs) must be cleaned to remove excess solder, rosins and other contaminants before placed into use. An ultrasonic cleaner is by far the fastest and most efficient method to safely clean these components when proper procedures are applied.
With trichloroethylene no longer available for cleaning PCBs, a substantial amount of posted information relates to cleaning, soaking and scrubbing using high purity alcohol, flux removal sprays and special biodegradable solvents. These manual processes are time consuming, could damage delicate components, can be environmentally unfriendly, and there is no guarantee that contaminants have been completely removed from complex PCB configurations. An ultrasonic cleaner such as the Elmasonic S series available from Tovatech is the practical answer to producing thoroughly clean high performance PCBs.
Addressing Earlier Concerns
In the past some PCB manufacturers have shied away from using ultrasonic cleaners. One concern related to possible water damage. Another related to single-frequency ultrasonic energy creating harmonic vibrations that could damage the components. These concerns no longer apply. Water can be used when the appropriate ultrasonic cleaning solution is employed and the PCBs are thoroughly dried after the cleaning step. As to component damage, ultrasonic cleaning equipment such as the Elma S series employs a feature called a Sweep Mode that continually shifts the ultrasonic sound field from a single harmonic wave that could cause damage. As an added benefit, the Sweep Mode optimizes the cleaning process, saving more time.
Preparation and Cleaning
Processes may vary depending on the ultrasonic cleaner selected, the cleaning solution and number of components being cleaned. In every case, PCB manufacturers should consult with suppliers of ultrasonic cleaners and solutions based on their particular components and cleaning requirements.
In a typical scenario an ultrasonic cleaning solution such as Tovatech’s CLN-OM-S14 diluted 1:10 with water is placed in the ultrasonic cleaner tank. New solutions should be degassed using the cleaner’s Degas function to remove entrained air that can interfere with and slow the actual cleaning process. When the solution is ready new PCBs (cooled below 70˚F) placed in a mesh basket are carefully lowered into the solution. The Sweep Mode is selected, the timer set and the unit is turned on.
Bottom mounted ultrasonic transducers attached to an ultrasonic generator create billions of microscopic bubbles that implode on contact with the PCBs in a process called ultrasonic cavitation. This effectively strips away all contaminants from all surfaces without damaging the PCB components. Depending on the number and complexity of the PCBs the process can be completed in as little as 10 – 15 minutes.
After the cleaning steps PCBs are thoroughly dried using an air blower or warm air dryer and are ready for use.
Source://www.seekic.com
