Solder Paste Material

Product Details

I. Solder Paste Composition

The solder paste composition of TS-503 consists of two main components: metal powder and solder flux. The alloy composition is Sn-Ag0.3-Bi35, with Bismuth (Bi) content ranging from 34.5% to 35.5%, Silver (Ag) content from 0.3% to 0.5%, and the balance being Tin (Sn). This unique solder paste composition design enables the solder paste to achieve medium-temperature soldering characteristics, with a melting point significantly lower than traditional SnAgCu-based solder paste.

II. Solder Paste Type & Solder Paste Type 4

TS-503 is classified under solder paste type as a medium-temperature lead-free solder paste, falling into the ROL1 no-clean solder paste type category. In terms of powder particle size, TS-503 adopts Type 4 (20–38μm) solder powder, belonging to the solder paste type 4 grade. This solder paste type is ideally suited for printing fine-pitch components (0.5mm and below).

Key advantages of choosing solder paste type 4 particle size include:

• Better suited for high-density, fine-pitch PCB designs
• Excellent release characteristics, reducing defects such as insufficient solder or missing prints
• Outstanding rollability and thixotropy when used with solder paste printer

Different solder paste type options (Type 3/Type 4/Type 5) cater to various applications. TS-503's Type 4 powder size strikes an optimal balance between fine-pitch printing capability and cost-effectiveness.

III. Solder Paste Lead Free

TS-503 is a typical solder paste lead free product, fully compliant with RoHS environmental directives. As a key member of the solder paste lead free series, TS-503 eliminates lead (Pb) from the formulation, with impurity lead content strictly controlled below 0.04%.

Choosing solder paste lead free is not only an environmental regulation requirement but also offers the following process advantages:

• High solder joint reliability with uniform IMC (Intermetallic Compound) layer growth
• Compliance with international environmental standards such as EU RoHS and REACH
• Alignment with the global lead-free trend in electronics manufacturing

As a solder paste lead free product, TS-503 provides a reliable lead-free medium-temperature solution for heat-sensitive components.

IV. SnAgBi Solder Paste

TS-503 belongs to the SnAgBi solder paste (Tin-Silver-Bismuth) family. Unlike traditional SnAgCu solder paste (Tin-Silver-Copper), SnAgBi solder paste significantly lowers the melting point of the solder paste (TS-503 at approximately 140°C, compared to SAC305 at approximately 217–221°C) by incorporating Bismuth (Bi) into the Tin-Silver alloy.

Core advantages of SnAgBi solder paste include:Low melting point:

• Suitable for components and substrates that cannot withstand high soldering temperatures
• Excellent wettability: Demonstrates superior spreading capability even at lower temperatures
• Cost advantage: Bismuth addition reduces silver content, making the material cost more competitive

As a representative product of SnAgBi solder paste, TS-503 holds irreplaceable advantages in medium-temperature soldering applications such as LED lighting, sensor modules, and flexible circuit boards.

V. Solder Paste Printer and Printing Process

TS-503 demonstrates excellent printing stability and extended stencil life when used with a Solder Paste Printer. The following parameters are recommended for Solder Paste Printer setup:

During Solder Paste Printer operation, metal squeegees or polyurethane rubber squeegees (hardness 80–90 Shore) are recommended, with a squeegee angle of 60°. The Type 4 powder size of TS-503, combined with precise Solder Paste Printer control, ensures consistent printing viscosity for over 8 hours with minimal variation, significantly improving production line efficiency.

VI. Solder Paste Mixer

TS-503 requires thorough thawing and mixing prior to use, which can be accomplished using a Solder Paste Mixer or by manual mixing:

• Refrigerated Storage: TS-503 should be stored at 5–10°C with a shelf life of 6 months; do not freeze
• Thawing Requirement: Allow to sit at room temperature for at least 4 hours before use to reach working temperature
• Manual Mixing: Mix manually for 3–6 minutes after thawing to ensure thorough homogenization of solder flux and metal powder
• Machine Mixing: Use a Solder Paste Mixer for 1–3 minutes for efficient and uniform mixing

Using a Solder Paste Mixer achieves more efficient and uniform mixing, preventing viscosity inconsistencies and printing defects caused by insufficient mixing. The recommended Solder Paste Mixer mixing time is 1–3 minutes; excessive mixing may raise paste temperature and affect performance.

VII. Solder Flux Performance

The solder flux contained in TS-503 is a core functional component, accounting for 10.5±1 wt% of the solder paste composition. This solder flux system features the following characteristics:

This solder flux employs low-ionic activators, ensuring excellent wettability while minimizing corrosiveness, resulting in minimal residue after reflow and reliable insulation performance, enabling true no-clean processing.

VIII. Solder Paste Physical Properties

As a high-performance solder paste, TS-503 demonstrates outstanding physical properties:

These excellent physical properties ensure TS-503 achieves extended continuous printing on a Solder Paste Printer without quality fluctuation, while maintaining stable printing performance across varying humidity conditions (30–60%RH).

IX. Recommended Reflow Profile

X. Target Applications and Recommended Industries

TS-503, as an SnAgBi solder paste, is particularly well-suited for:

• LED Lighting Modules – LED chips have limited temperature tolerance; medium-temperature solder paste prevents thermal damage
• Consumer Electronics – Smartphones, tablets, and other thin-profile designs are sensitive to soldering temperatures
• Automotive Electronics – Certain in-vehicle sensors require medium-temperature soldering processes
• Flexible Printed Circuits (FPC) – Flexible substrates cannot withstand high-temperature reflow
• Heat-Sensitive Components – Thermal devices, thermistors, and similar components

As a solder paste lead free product, TS-503 simultaneously meets the dual requirements of lead-free compliance and medium-temperature soldering, making it an ideal choice for heat-sensitive component SMT processes.