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Model : Kester FL250DS SOLDER PASTE
Type : Soldering & Cleaning
Simple Explanation
Excellent residue characteristics that are completely compatible with conformal coating and potting processes.
High print speeds to 200mm/sec (8 in/sec).
Compatible with 0201 technology.
Excellent printing characteristics to 0.4mm (16 mil) pitch with Type 3 powder.
Excellent wetting on a variety of substrates, including OSPs.
Capable of 90 minute break times in printing.
Scrap is reduced due to less paste dry out.
Stable tack over 8+ hours.
Classified as ROL0 per J-STD-004.
Compliant to Bellcore GR-78-CORE(uncleaned).
Compatible with DEK ProFlowTM and MPM RheopumpTM enclosed print head systems.

Product Description
Kester FL250DS is a no-clean, air or nitrogen reflowable solder paste specifically designed for automotive requirements. FL250DS is compatible with post-soldering process chemicals, including conformal coatings and potting compounds. FL250DS is capable of stencil printing downtimes of up to 90 minutes with an effective first print at 20mils. FL250DS also has the capability of printing up to 200mm/sec (8in/sec) with squeegees or within an enclosed head.


Standard Applications
90% Metal -- Stencil Printing.
90% Metal ? Enclosed Head Printing.


Physical Properties
(Data given for Sn63/Pb37,90% metal, -325+500 mesh)
Viscosity (typical) : 1600 poise
Malcom Viscometer @ 10 rpm and 25°C
Initial Tackiness (typical) : 42 grams
Tested to J-STD-005, IPC-TM-650, Method 2.4.44
Slump Test: Pass
Tested to J-STD-005, IPC-TM-650, Method 2.4.35
Solder Ball Test: Preferred
Tested to J-STD-005, IPC-TM-650, Method 2.4.43
Wetting Test: Pass
Tested to J-STD-005, IPC-TM-650, Method 2.4.45


Recommended Reflow Profile

The recommended convection reflow profile for FL250DS formula made with either the Sn63Pb37 or Sn62Pb36Ag02 is shown here. This profile is simply a guideline. Since FL250DS is a highly active, no-clean solder paste, it can solder effectively over a wide range of profiles. Your optimal profile may be different from the one shown based on your oven, board and mix of defects. Please contact Kester if you need additional profiling advice.