Lead Free Solder Paste

Lead-Free Solder Paste The key variables in Lead-Free SMT are the higher reflow temperatures, flux activities, residue characteristics, cleanability, and pin testability. The slower wetting speeds associated with Lead-Free alloys require enhanced flux systems. Kester solder pastes have novel flux systems that are specifically designed for Lead-Free assembly. These new flux systems promote good wetting and excellent solder joint integrity at the higher temperatures commonly seen with most Lead-Free alloys such as SnAgCu.

No-Clean Lead-Free Solder Paste Formulas

Formula Application Product Characteristics Residue Removal Method Atmosphere Required for Reflow Compliant Specifications
R905 Stencil Printing Kester Lead-Free solder paste with a fine printing capability of 20 mils and a printing speed of 150mm/sec. Suitable for CSP and 0201 applications. Exhibits excellent compatibility with a wide variety of metallisation. The Exquisite paste flux system allows for a wide process printing window. Not normally required but its residue can be easily removed using automated cleaning equipment (in-line or batch) with Kester #5252M Solvent Cleaner or #5260 Aqueous Cleaner. Air or Nitrogen Bellcore Issue 1
GR-78-Core
IPC ANSI/J-STD-004
Flux Designator R0L0
TCS-502-3 Stencil Printing A highly reliable paste with high insulation resistance flux residue. Exhibits great viscosity stability and excellent wettability. A robust paste that can be re-use even after printing. Not normally required. Air or Nitrogen JIS-Z-3197
JIS-Z-3284
TCS-531-1 Stencil Printing A newly developed Lead-Free paste that solves your CSP/BGA and fine pitch printing problems. TCS-531-1 uses fine solder powder and its flux system exhibits high reliability with high insulation and corrosion resistance. Not normally required. Air or Nitrogen JIS-Z-3197
JIS-Z-3284
TCS-552-1 Stencil Printing Designed for the fine pitch printing. Possesses good printing characteristics that do not promote bridging or smearing. The flux system is capable of controlling deactivation during pre-heating in order to achieve superior wettability and solder joints. A very stable paste suitable for long time printing. Not normally required. Air or Nitrogen JIS-Z-3197
JIS-Z-3284
R276 Syringe Dispensing Provides optimal performance in all types of dispensing applications. R276 is packaged void-free to ensure consistent dispensing in high speed automated processes. Exhibits excellent dispensing characteristics with a wide range of needle diameters. Not normally required. Air or Nitrogen Bellcore Issue 1
GR-78-Core
IPC ANSI/J-STD-004
Flux Designator R0L0

Water-Soluble Lead-Free Solder Paste Formulas

Formula Application Product Characteristics Residue Removal Method Atmosphere Required for Reflow Compliant Specifications
R520A Stencil Printing Designed to withstand higher temperatures that are needed when soldering with Lead-Free alloys. R520A exhibits minimal voiding, long stencil life and track time while still delivering exceptional solderability to a wide variety of metallic substrates. Its residue can be easily removed using automated cleaning equipment (in-line or batch). Using de-ionised water at 49-60°C (120°F-140°F) or with 2% solution of Kester #5768 Bio-Kleen saponifier. Air or Nitrogen IPC ANSI/J-STD-004
Flux Designator 0RH0
EnviroMark 522 Stencil Printing An organic acid formula specifically designed for the printing requirements of CSP, GBA and 0201 components. Its excellent paste release and print stability makes it ideal for challenging designs with ultra-fine pitches and small stencil openings. Offers good solderability and excellent wettability. Its residue can be easily removed using automated cleaning equipment (in-line or batch). Use de-ionised water at 49°C-60°C (120°F-140°F). Air or Nitrogen IPC ANSI/J-STD-004
Flux Designator 0RH0
R505 Syringe Dispensing Specially designed as a consistent dot dispensing paste for automated dispense equipment. The activator package in this formula is extremely aggressive; to remove tenacious oxide layers or to solder to OSP coated boards. Excellent dispensing characteristics with a capability to dispense 4 dots per second. Its residue can be easily removed using automated cleaning equipment (in-line or batch). Use de-ionised water at 49°C-60°C (120°F-140°F) or with 2% solution of Kester #5768 Bio-Kleen saponifier. Air or Nitrogen IPC ANSI/J-STD-004
Flux Designator 0RH0