Lead-Free Solder Paste

Lead-Free Solder Paste – TENSAN TS-501 Mid-Temperature Solution

In today's global electronics industry, environmental compliance is not optional – it is a fundamental requirement. RoHS, REACH, and other regulations mandate the elimination of lead from electronic products, making the choice of a reliable solder paste lead free formulation critical for every SMT assembly line. Beyond mere compliance, the right lead-free solder paste must deliver excellent printability, strong wetting, and reliable joint formation – all while protecting heat-sensitive components and maintaining production efficiency.

TENSAN TS‑501 is a Lead-Free Solder Paste engineered to meet these demands. Formulated with a Sn‑Ag1‑Bi35 alloy, this solder paste lead free solution offers a lower melting point than conventional SAC alloys, making it ideal for assemblies with thermal‑sensitive components, flexible PCBs, and step‑soldering processes. With Type‑4 powder, ROL1 flux classification, and no‑clean residue, TS‑501 is the lead-free solder paste that combines environmental responsibility with outstanding process performance.

What Is TENSAN TS‑501 Lead-Free Solder Paste?

TS‑501 is a no‑clean solder paste lead free product designed for SMT assembly processes that require:

• Full RoHS compliance – 100% lead‑free alloy (Sn‑Ag1‑Bi35), meeting global environmental standards
• Lower reflow temperatures – Bismuth content reduces melting point to protect heat‑sensitive components
• Excellent printability – Type 4 powder (20–38 μm) ensures consistent deposit volume and shape retention
• No‑clean convenience – Clear, minimal residue that supports ICT testing without cleaning
• Long stencil life – Stable rheology maintains print performance over extended production shifts
• High reliability – Passes SIR and electromigration tests for long‑term electrical stability

Whether you are manufacturing LED lighting, automotive electronics, or consumer devices, this lead-free solder paste delivers the performance and compliance you need.

Key Specifications

Alloy Composition & Physical Properties

Chemical & Electrical Properties

Physical Properties

Test methods conform to IPC J‑STD‑004, IPC J‑STD‑005, JIS Z 3284, and Bellcore GR78‑CORE standards.

Why Choose TENSAN TS‑501 as Your Lead-Free Solder Paste?

1. Full Environmental Compliance – A Responsible Solder Paste Lead Free Choice

TS‑501 is manufactured with a 100% lead‑free alloy, fully compliant with RoHS Directive requirements. By choosing this solder paste lead free product, you eliminate the risk of non‑compliance penalties and ensure that your products can be exported to all major global markets. This lead-free solder paste also meets REACH and other regional environmental standards, giving you peace of mind in your supply chain.

2. Unique Bi35 Alloy – Lower Reflow Temperatures

Unlike standard SAC305, this solder paste lead free product uses a Sn‑Ag1‑Bi35 alloy that significantly reduces the melting point. The peak reflow temperature of 210–230°C protects heat‑sensitive components such as LEDs, plastic connectors, and flexible substrates from thermal degradation. This makes TS‑501 the ideal lead-free solder paste for assemblies that cannot tolerate high temperatures, while still providing strong, reliable joints.

3. Excellent Printability – Consistent Fine‑Pitch Performance

With Type 4 powder (20–38 μm), TS‑501 delivers:

• Consistent paste volume transfer for fine‑pitch applications down to 0.25 mm
• Sharp edge definition and minimal slump after printing
• Compatibility with both standard and fine‑pitch stencil designs

Whether you use an automatic printer or manual equipment, this lead-free solder paste adapts to your process requirements, ensuring high first‑pass yields.

4. No‑Clean, Low‑Residue – Saves Process Steps

The flux system leaves a clear, non‑conductive residue that:

• Supports ICT (In‑Circuit Test) without post‑reflow cleaning
• Eliminates cleaning process steps, reducing chemical costs and cycle time
• Maintains high surface insulation resistance even under humid conditions (SIR > 1.7 × 10⁹ Ω)

This no‑clean design makes TS‑501 a highly efficient solder paste lead free product for high‑volume production.

5. Long Stencil Life and Stable Viscosity

TS‑501 maintains consistent viscosity for:

• Over 8 hours on stencil under normal production conditions (22°C, 50% RH)
• Reduced stencil cleaning frequency and less paste waste
• Stable printing performance across entire production shifts

This stability ensures that your lead-free solder paste printer operates at peak efficiency with minimal interruptions.

6. High Electrical Reliability – Essential for Long‑Term Performance

With SIR exceeding 1.7×10⁹ Ω (IPC) and 6.4×10¹² Ω (Bellcore), and passing 500‑hour electromigration testing, TS‑501 ensures that the residue left by this solder paste lead free product does not compromise long‑term reliability – even in humid environments. This makes it a trusted lead-free solder paste for automotive, telecommunications, and industrial applications.

Recommended Application Parameters

Stencil Design Guidelines

Stencil Technologies: Electroformed and laser‑cut stencils with electro‑polishing provide optimal printing characteristics. "Roof‑shaped" aperture designs help reduce solder balling between components.

Printing Conditions

Reflow Profile (Recommended)

The lower peak temperature of this lead-free solder paste provides a protective thermal environment for heat‑sensitive components while still delivering strong, reliable solder joints. Adjust profiles based on your specific reflow oven and PCB assembly requirements.

Storage and Handling Guidelines for This Solder Paste Lead Free Product

Important: Do not mix leftover paste with fresh paste in the same container. Always warm up this lead-free solder paste in its sealed container to prevent moisture condensation, which can cause spattering during reflow.

Alloy Composition Overview (Lead-Free)

Lead content is strictly controlled below 0.04%, ensuring full RoHS compliance for this solder paste lead free product.

Typical Applications for This Lead-Free Solder Paste

TS‑501 is ideal for applications requiring lower reflow temperatures and full environmental compliance:

• LED Lighting – Protects LED chips and phosphor layers from thermal degradation
• Consumer Electronics – Smartphones, tablets, wearables with heat‑sensitive components
• Automotive Electronics – Sensors, lighting modules, ECUs
• Flexible PCBs – Prevents warpage and delamination of flexible substrates
• Step‑Soldering Processes – Secondary reflow after high‑temperature SAC assembly
• Telecommunications – RF modules, base station components

As a versatile solder paste lead free product, TS‑501 is trusted by manufacturers across these diverse industries.

Quality Assurance

Every batch of TENSAN TS‑501 is accompanied by a Certificate of Analysis confirming:

• Model and batch number
• Alloy composition (Sn‑Ag1‑Bi35) – verified lead‑free
• Flux content (wt%)
• Viscosity at 25°C

Our manufacturing processes ensure consistent product quality from lot to lot, giving you confidence in every production run with this lead-free solder paste.

Frequently Asked Questions

Q: Is TS‑501 fully lead‑free and RoHS compliant?

A: Yes. TS‑501 is a 100% solder paste lead free product, with lead content below 0.04%, fully compliant with RoHS and REACH requirements. This lead-free solder paste is safe for use in all global markets.

Q: How does this lead-free solder paste differ from SAC305?

A: TS‑501 contains 35% bismuth, which lowers the melting point significantly compared to SAC305. This makes it a superior solder paste lead free choice for heat‑sensitive components and step‑soldering processes.

Q: Is TS‑501 compatible with standard SMT equipment?

A: Yes. This lead-free solder paste works with all standard automatic and semi‑automatic printers, as well as standard reflow ovens. Its Type‑4 powder supports fine‑pitch printing down to 0.25 mm.

Q: Does TS‑501 require post‑reflow cleaning?

A: No. TS‑501 is a no‑clean solder paste lead free product. The residue is clear, non‑conductive, and compatible with ICT testing, eliminating cleaning steps and reducing costs.

Q: What is the shelf life of this lead-free solder paste?

A: Six months from production date when stored at 5–10°C. At room temperature, it can be kept for up to 15 days.

Q: Can TS‑501 be used for nitrogen reflow?

A: Yes, it performs well in both air and nitrogen reflow environments.

Q: What industries commonly use this solder paste lead free product?

A: TS‑501 is widely used in LED lighting, consumer electronics, automotive, flexible PCB, and telecommunications manufacturing – anywhere that lead‑free compliance and lower reflow temperatures are required.

Conclusion

For manufacturers who demand environmental compliance without compromising performance, TENSAN TS‑501 is the definitive lead-free solder paste solution. This solder paste lead free product offers lower reflow temperatures, excellent printability, stable viscosity, no‑clean convenience, and proven electrical reliability – all in one cost‑effective formulation.

By choosing TS‑501, you select a Lead-Free Solder Paste that:Fully meets RoHS and REACH requirementsProtects heat‑sensitive components with lower reflow temperaturesDelivers consistent, fine‑pitch print performanceEliminates cleaning steps with no‑clean residueEnsures long‑term reliability with high SIR and electromigration resistanceUpgrade to TENSAN TS‑501 – the lead-free solder paste that combines compliance, performance, and reliability.

Contact Information

TENSAN VIETNAM CO., LTD

TS10 Road, Tien Son Industrial Park, Bac Ninh Province, Vietnam

Tel: +84‑222‑650‑8818

Email: mark@sztensan.com