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Features:
· PIN-PROBE TESTABLE RESIDUES · EXCELLENT WETTING
· 12-14 HOUR STENCIL LIFE · AIR REFLOW / NITROGEN NOT NECESSARY
· 8-12 HOUR TACK TIME · AQUEOUS CLEAN WITH SAPONIFIER
· PRINTS UP TO 6 INCHES PER SECOND · REDUCES VOIDING ON MICRO-BGA’S
* Passes BELLCORE (Telecordia GR-78-Core Flux Requirements) and IPC (product testing summary on third page, data available upon request)
Description:
NC251 is a mildly activated, resin-based formulation developed to offer pin-probeable residues. In addition, NC251 has proven to reduce voiding on BGAs and offers excellent activity and wetting characteristics, superior slump resistance, and excellent printing characteristics. NC251 also offers high humidity tolerance and a chemistry developed for use in air reflow. Slump and humidity tolerances found in NC251 extend the solder pastes useable life in facilities where environmental control is not at its optimum. NC251 has been utilized on various assemblies with RF designs without cleaning; however, the compatibility of flux residues on RF assemblies is strongly dependent upon circuitry design.
Standard Paste Composition:
|
Application Method |
IPC Powder Type
|
Metal Load |
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Standard Stencil Printing |
3 |
90.25% |
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Fine Pitch Stencil Printing |
5 |
89.75% |
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Ultra-Fine Pitch Stencil Printing |
5 |
89.25% |
|
Dispensing syringes |
3 |
85.00% |
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Note: These are typical starting guidelines. To achieve optimal performance, actual metal load and particle size may vary per process, application, and environment. |
Handling:
- ·NC251 has a refrigerated shelf life of 1 year, at 4°C (40°F), and a non-refrigerated shelf life of 6 months at 22°C (72°F). Do not freeze this product.
- Allow the solder paste to warm completely and naturally to ambient temperature; (8 hours is recommended), prior to breaking seal for use.
- Mix the product lightly and thoroughly for 1 to 3 minutes to ensure even distribution of any separated material resulting from storage.
- Do not store new and used paste in the same container. Re-seal any opened containers while not in use.
- Replace the internal plug in conjunction with the cap of the 500 gram jar to ensure the best possible seal.
Printer Setup
Suggested starting parameters for your screen printer. Assumptions were made as to the printer types used in today’s applications, and adjustments will vary between equipment, application and facility environment.
SNAP-OFF DISTANCE ON CONTACT - 0.00”
SQUEEGEE PRESSURE - 0.6 -0 .7 LBS/IN. OF BLADE
PCB SEPARATION DISTANCE - .030-.050”
SQUEEGEE STROKE SPEED - .5 - 6 IN/SEC * DEPENDENT ON PCB AND PAD DESIGNS
PCB SEPARATION SPEED - MEDIUM
Paste Application:
· Apply sufficient paste to the stencil to allow a smooth, even roll during the print cycle. A bead diameter of 1/2 to 5/8 inch is normally sufficient to begin.
· Apply small amounts of fresh solder paste to the stencil at frequent, controlled intervals to maintain paste chemistry and workable properties.
· Cleaning of your stencil will vary according to the application; however, it can be accomplished using AIM’s 200AX-10 or DJAW-10 stencil cleaners. Use these in moderation and remove any excess cleaner from the stencil surface.
· NC251 provides the necessary tack time/force for today’s high-speed placement equipment. Ensuring proper support of PCBs during assembly and handling will enhance product performance and reliability.
· For technical advice, consult the AIM web page at www.aimsolder.com
Reflow Data:
Cleaning:
NC251 can be cleaned, if necessary, with a saponified tap water. AIMTERGE-520 is recommended. DI-water is recommended for the final rinse. A temperature of 120 - 150ºF is sufficient for removing any residues. An in-line or other pressurised spray cleaning system is suggested, but is not required.
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