NC Paste Flux is a no clean tacky/rework flux designed to wet virtually all solderable electronic surfaces, components, assemblies, and substrates. AIM NC Paste Flux may be used for general touch up or rework of printed circuit boards, and for attaching spheres to ball grid array (BGA) packages.
The superior wetting ability of NC Paste Flux results in bright, smooth and shiny solder joints whether reflowed by hand, hot-air rework station, convection reflow oven, or vapor phase soldering systems. Residues that remain on surfaces after soldering are clear, leaving a cosmetically appealing repair that can be easily pin probed during in-circuit test. NC Paste Flux is compatible with all tin-lead and lead-free alloys and is suitable for a wide range of applications. NC Paste Flux can be brushed, dispensed, pin transferred, or stencil printed. NC Paste Flux is available in 10cc and 30cc syringes.
Features:
- Excellent Wetting
- Wide Process Window
- Tin-Lead and Lead-Free Compatible
- Used for Ball Attach
Printing:
- Apply sufficient paste to the stencil to allow a smooth, even roll during the print cycle (a bead diameter of 12 to 16 mm (½ to ⅝ inch) is normally sufficient to begin).
- Apply small amounts of fresh solder paste to the stencil at controlled intervals to maintain paste chemistry and workable properties.
- NC254 provides the necessary tack time and force for today’s high speed placement equipment, which will enhance product performance and reliability.
- Cleaning of your stencil will vary by application, however, it can be accomplished using AIM 200AX-10 stencil cleaner.
- Snap-off distance = on contact 0.00 mm (0.00”)
- PCB Separation Distance = 0.75-2.0 mm (.030-.080”)
- PCB Separation Speed = Slow
- Squeegee Pressure = 0.10-0.30 kg/cm (.6 -1.7 lbs/in.) of blade
- Squeegee Stroke Speed = 25-50 mm/sec. (1-2 in./sec.)
• Note: Recommended initial printer settings above are dependent on PCB and pad design
Reflow Profile:
Two unique profile families are depicted below; both can be used in ramp-spike or ramp-soak-spike applications, and they each have similar reflow temperatures.
The two profiles differ in where they reach their respective peak temperatures, as well as the time above liquidus (TAL). The shorter profile of the two would apply to smaller assemblies, where as the longer profile would apply to larger assemblies, such as backplanes or high-density boards.
The shaded area defines the process window. Oven efficiency, board size/mass, component type and density all influence the final profile for a given assembly.
These profiles are starting points, and processing boards with thermal-couples attached is recommended to optimize the process.
- THE RECOMMENDED REFLOW PROFILE FOR NC254 IS PROVIDED AS A GUIDELINE. OPTIMAL PROFILE MAY DIFFER DUE TO OVEN TYPE, ASSEMBLY LAYOUT, OR OTHER PROCESS VARIABLES. CONTACT AIM TECHNICAL SUPPORT IF YOU REQUIRE ADDITIONAL PROFILING ASSISTANCE.
- THE REFLOW PROFILE FOR THE Sn/Pb PASTES USING A VAPOR PHASE REFLOW OVEN:PEAK TEMPERATURE RANGE I S 230°C–245°C.
