TS-502 is a lead-free low-temperature solder paste. This SnBi Solder Paste features a eutectic melting point of only 138°C, specifically designed for soldering heat-sensitive components and flexible substrates. TS-502 is precision-engineered with Type 3/4 spherical solder powder and Solder Flux to deliver excellent continuous printing resolution on the Solder Paste Printer. Prior to use, thorough mixing via a Solder Paste Mixer is recommended to ensure uniform Solder Paste Composition. This Solder Paste Lead Free product has been widely adopted in low-temperature assembly applications including LED modules, sensors, and high-frequency components, with sufficient monthly production capacity to guarantee stable supply.
Product Details
I. Solder Paste Composition
The Solder Paste Composition of TS-502 consists of Sn42/Bi58 alloy powder and Solder Flux. According to the technical datasheet, the Solder Paste Composition contains 41.5–42.5% Tin and 57.5–58.5% Bismuth, forming a eutectic alloy with both liquidus and solidus at 138°C. The Solder Flux within this Solder Paste Composition is formulated with hydrogenated rosin (45–48%), straight-chain C9-C12 aliphatic alcohol (20–22%), cyclical C12-C16 ester (9–15%), polymerized fatty oil (4–6%), di-carboxylic acid activator (4–8%), and organic amine C8-C10 (2–3%). The Solder Flux content is 10.0±1wt% with halogen content below 0.05wt%, ensuring the SnBi Solder Paste leaves minimal residue after reflow with reliable insulation performance. The metal content of this Solder Paste Composition is 90.0%, with a specific gravity of 8.7g/cm³.
II. Solder Paste Type and Printing Performance
TS-502 features a powder particle size of 25–45μm, positioned between Solder Paste Type 3 (25–45μm) and Solder Paste Type 4 (20–38μm), making it suitable for both conventional and fine-pitch printing applications. On the Solder Paste Printer, this SnBi Solder Paste operates with the following printing parameters: squeegee speed 20–60mm/s, pressure 1.0–2.0kg/cm² (10–20N, 100–200kPa), and squeegee angle 50–70°. TS-502 exhibits minimal viscosity variation during continuous printing on the Solder Paste Printer, delivering exceptionally stable printability, and maintains stable performance even at humidity levels up to 80% RH (the datasheet notes that TS-502 is non-hydrophilic and insensitive to humidity), with stencil life exceeding 8 hours.
III. Solder Paste Lead Free and SnBi Alloy Advantages
TS-502 is a typical Solder Paste Lead Free product with lead content below 0.001%, fully compliant with RoHS directives. The Sn42/Bi58 eutectic alloy used in this Solder Paste Lead Free product exhibits the following properties: tensile strength of 55MPa with 13% elongation at 25°C, and 28MPa with 18% elongation at 100°C, with a thermal expansion coefficient of 13.4×10⁻⁶/°C. Compared to SnAgCu Solder Paste, this SnBi Solder Paste has a melting point approximately 80°C lower, making it particularly suitable for soldering components and substrates with poor heat resistance. As a SnBi Solder Paste, it demonstrates excellent creep resistance and thermal fatigue performance, with mass adoption in low-temperature applications including LED lighting modules, automotive sensors, and high-frequency components.
IV. Solder Flux and Electrical Reliability
The Solder Flux in TS-502 employs a low-ionic activator system, having passed all three tests—Copper Mirror Test, Copper Corrosion Test, and Silver Chromate Paper Test—with no corrosion risk. This Solder Flux ensures the SnBi Solder Paste achieves Surface Insulation Resistance (SIR) exceeding 1×10⁶Ω·cm, electromigration resistance exceeding 1.02×10⁶Ω·cm, water extraction resistance of 102KΩ, slump below 0.2mm, and spreadability exceeding 90%. The solder ball test shows virtually no solder ball occurrence (Solder Ball Test PASS), with residue remaining dry and non-tacky. With this Solder Flux system, TS-502 delivers exceptionally high reliability in No-Clean processes even without post-reflow cleaning.
V. Solder Paste Mixer and Process Guidelines
TS-502 requires thawing for 4–6 hours at 25°C before use, followed by mixing via a Solder Paste Mixer or manual stirring. The Solder Paste Mixer is recommended to operate for 2–5 minutes (with the container sealed), while manual stirring requires 3–6 minutes to ensure uniform Solder Paste Composition with viscosity restored to 180±20Pa·s (Brookfield DV-E Viscometer @25°C, 10rpm). After printing this SnBi Solder Paste on the Solder Paste Printer, component placement should be completed within 3–6 hours to prevent the Solder Paste surface from drying out. The reflow profile recommends a peak temperature of 170–185°C, with time above 138°C maintained at 50–90 seconds, time above 150°C at 30–60 seconds, and a ramp rate of 0.5–2.0°C/sec.
VI. Application Scenarios and Supply Capacity
This SnBi Solder Paste has been deployed in volume production across three major sectors: Consumer Electronics (TWS earbuds, smart wearables), LED Lighting (COB modules), and Automotive Electronics (BMS, in-vehicle sensors), serving over 30 customers. TS-502 maintains a monthly production capacity exceeding 2 tons with ample inventory, enabling delivery within 72 hours to fully support continuous SMT line production requirements.
