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Ultrasonic stencil cleaners

dalejans

#17874

Ultrasonic stencil cleaners | 12 October, 2001

Is it acceptable to clean an assembled board in the ultasonic stencil cleaner? The cleaning requirement is where water soluable flux is used and needs to be removed.

Thanks for you information!

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#17877

Ultrasonic stencil cleaners | 12 October, 2001

Hi,

Maybe Yes� Maybe No�

Actually, it most likely is acceptable to clean assembled boards in an ultrasonic cleaning system (40 kHz). There are some concerns in some circles about possible damage to wire bonds in components. There have been published articles that refute this concern but there are still some �old-timers� that are not convinced. Ultrasonics are excellent in removing flux. Rinsing is critical though as many ultrasonic cleaners are not designed to rinse with the impingement necessary to remove the wash water. Also, ultrasonic cleaners are not normally equipped with fast and efficient drying systems.

Spray-in-air systems are always acceptable methods of de-fluxing boards and are not subject to the same controversy.

Mike Konrad Aqueous Technologies (909) 944-7771

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#17894

Ultrasonic stencil cleaners | 15 October, 2001

Hi Dale,

I have copies of the articles of which Mike references. If you need copies for support, contact me at: bill@smartsonic.com.

Rinsing should be done by ultrasonics also. Spray in atmosphere systems will not penetrate into the same tight areas as u/s. A second ultrasonic bath with fresh DI water should be used. We recommend a rinse cycle of at least one-half the time as the ultrasonic wash cycle.

However, if these boards are double-sided misprints, (paste on side B and components on side A) be careful. Not all water washable solder paste cleans effectively with water alone. The post-solder flux residue may clean OK, but the paste may need a surfactant. Orientation of the board is also important in order to prevent solder ball contamination.

Please feel free to call or e-mail me if you need additional information.

Good luck.

Bill Schreiber Smart Sonic Corporation Tel: 1-818-909-6400 E-mail: bill@smartsonic.com

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Eric Chua

#17964

Ultrasonic stencil cleaners | 19 October, 2001

Hi,

Not so sure. I know one of the equipment can do it, there is Kolb RB6D. This system can clean stencil, misprint, assembly board, etc. This Kolb also provide chemcil for the correct cleaner.

Hope this can help you. Email to me if you need any help. ericchua@smtnet.com

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#17970

Ultrasonic stencil cleaners | 22 October, 2001

Eric,

The Kolb RB6D (and the RB5D) are not ultrasonic cleaners. They are high pressure spray cleaners. I would not recommend high pressure spray cleaners for misprinted assemblies with previously placed components (unless you don�t mind solder paste blasted under a component).

High pressure spray-in-air cleaners are great for post-reflow de-fluxing where getting under a component is the objective. If the misprinted assembly is not populated, then spray-in-air systems do well. Otherwise, stick with ultrasonic systems.

Mike

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