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How actually the process of Electrofoam Stencil?

Deepak Mudliar

#31927

How actually the process of Electrofoam Stencil? | 7 January, 2005

Following are my queries : 1. How actually the process of electrofoam Stencil preparation?

2. How N2 Helps for Leadfree soldering ? 3. Does Ultrasonic Cleaning process affects the internal bonding of IC ?

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Rob

#31928

How actually the process of Electrofoam Stencil? | 7 January, 2005

3) Not usually a problem on IC's, however on certain crystal/frequency products there have been issues with harmonics causing damage. Also would not like to speculate what would happen with the new ranges of MEM's silicon sensors.

Cheers,

Rob.

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#31933

How actually the process of Electrofoam Stencil? | 7 January, 2005

Electroformed stencil suppliers follow. The describe the stencil production process on their sites. * Aplpha Metals [ http://www.alphametals.com/products/ stencils/pdf/PG_Electroform_Stencils.pdf ] * Chepaume [ http://www.chepaume.com/electroforming.html ]

Potential benefits of using a nitrogen atmosphere follow: * Improved wetting. * Less solder-paste residues. * Less oxidation. * Protection of OSP-treated PCB due to low oxygen levels. * Preheating support of VOC-free fluxes. * Preservation of soldering conditions for multiple soldering steps. * Increased process window. * Reduced solder balls. * Less voiding.

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#31937

How actually the process of Electrofoam Stencil? | 7 January, 2005

3) There are several papers on the safety of cleaning PCBs and ICs using ultrasonic technology. The latest is in the October 2004 issue of SMT magazine by William Kenyon, "Why Not Ultrasonics?" Most of the studies have been performed by Dr. B.P. Richards of GEC Marconi and the EMPF Lab.

Dr. Richards published a report in Circuit World, Vol. 18, No. 4, "The Effects of Ultrasonic Cleaning on Device Degradation - Quartz Crystal Devices." In his conclusion he states "...ultrasonic cleaning of boards containing such devices can be undertaken, but with some caution." I have these articles in electronic format. If you would like a copy, send me an e-mail.

A good summary of the precautionary cleaning parameters can be found at the following URL: http://www.smartsonic.com/news.html

Regards, Bill Schreiber Smart Sonic Stencil Cleaning Systems Tel: 1(818) 610-7900 E-mail: bill@smartsonic.com

Web: http://www.smartsonic.com

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