No-Clean Solder Paste

No-Clean Solder Paste – TENSAN TS-503 Mid-Temperature Solution

In modern SMT assembly, the choice of solder paste directly impacts production efficiency, component reliability, and long‑term product performance. TENSAN TS‑503 is a No-Clean Solder Paste engineered specifically for medium‑temperature reflow processes, offering the ideal balance between thermal protection and soldering performance. This advanced solder paste formulation features a unique Sn‑Ag0.3‑Bi35 alloy, delivering a significantly lower melting point than conventional SAC305 pastes while maintaining excellent wettability and joint reliability. As a true No-Clean Solder Paste, TS‑503 eliminates post‑reflow cleaning, reduces process costs, and ensures high electrical reliability – making it the preferred solder paste for LED lighting, flexible circuits, and heat‑sensitive component assemblies.

What Is TENSAN TS-503 No-Clean Solder Paste?

TENSAN TS‑503 is a lead‑free, no‑clean solder paste designed for SMT assembly processes that demand medium‑temperature reflow and superior cleanliness. This No-Clean Solder Paste is formulated with a Sn‑Ag0.3‑Bi35 alloy, offering:Lower reflow temperature – Bismuth content (34.5–35.5%) reduces melting point, protecting heat‑sensitive componentsNo‑clean convenience – Minimal, clear residue that supports ICT testing without cleaningFull RoHS compliance – 100% lead‑free, meeting global environmental standardsExcellent printability – Type 4 powder (20–38 μm) ensures consistent deposit volume for fine‑pitch applicationsLong stencil life – Stable rheology maintains print performance over extended production shiftsHigh reliability – Passes SIR and electromigration tests for long‑term electrical stabilityAs a No-Clean Solder Paste, TS‑503 is trusted by manufacturers across LED lighting, automotive electronics, consumer devices, and telecommunications for its consistent performance and thermal protection capabilities.

Key Specifications

Alloy Composition & Physical Properties

Chemical & Electrical Properties

Physical Properties

Why Choose TENSAN TS-503 as Your No-Clean Solder Paste?

1. Medium-Temperature Alloy – Protects Heat-Sensitive Components

TS‑503 uses a Sn‑Ag0.3‑Bi35 alloy that significantly reduces the melting point compared to standard SAC305. 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 this No-Clean Solder Paste the ideal choice for assemblies that cannot tolerate high temperatures, while still providing strong, reliable joints.

2. Low Silver Content – Cost-Effective Formulation

With silver content reduced to 0.3–0.5% (compared to 3.0% in SAC305 or 1.0% in SAC105), TS‑503 offers significant material cost savings while maintaining excellent soldering performance. This No-Clean Solder Paste provides the perfect balance between cost and reliability, making it an attractive solder paste choice for high‑volume production.

3. Excellent Printability – Consistent Fine‑Pitch Performance

With Type 4 powder (20–38 μm), TS‑503 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 No-Clean 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‑503 a highly efficient solder paste for high‑volume production.

5. Long Stencil Life and Stable Viscosity

TS‑503 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 No-Clean 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‑503 ensures that the residue left by this solder paste does not compromise long‑term reliability – even in humid environments. This makes it a trusted No-Clean 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 No-Clean 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

Important: Do not mix leftover solder paste with fresh paste in the same container. Always warm up this No-Clean Solder Paste in its sealed container to prevent moisture condensation, which can cause spattering during reflow.

Alloy Composition Overview

Typical Applications for This No-Clean Solder Paste

TS‑503 is ideal for applications requiring lower reflow temperatures and no‑clean processing:

• 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 requiring medium‑temperature soldering
• 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
• Heat‑Sensitive Components – Thermal devices, thermistors, and similar components

As a versatile No-Clean Solder Paste, TS‑503 is trusted by manufacturers across these diverse industries.

Quality Assurance

Every batch of TENSAN TS‑503 is accompanied by a Certificate of Analysis confirming:

• Model and batch number
• Alloy composition (Sn‑Ag0.3‑Bi35)
• Powder size distribution (Type 4, 20–38 μm)
• Flux content (wt%)Viscosity at 25°C

Our manufacturing processes ensure consistent solder paste quality from lot to lot, giving you confidence in every production run with this No-Clean Solder Paste.

Frequently Asked Questions

Q: What makes TS‑503 a no-clean solder paste?

A: TS‑503 is formulated with a flux system that leaves a clear, non‑conductive, non‑corrosive residue after reflow. This residue does not require removal and supports ICT testing without cleaning, making it a true No-Clean Solder Paste.

Q: How does TS‑503 differ from TS‑501?

A: TS‑503 has a lower silver content (0.3–0.5%) compared to TS‑501 (0.9–1.1%). This further reduces material costs while maintaining good soldering performance for less demanding applications. Both are No-Clean Solder Paste products with medium‑temperature alloys.

Q: Is TS‑503 compatible with standard SMT equipment?

A: Yes. This 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‑503 require post‑reflow cleaning?

A: No. TS‑503 is a No-Clean Solder Paste. 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 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‑503 be used for nitrogen reflow?

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

Q: What industries commonly use this No-Clean Solder Paste?

A: TS‑503 is widely used in LED lighting, consumer electronics, automotive, flexible PCB, and telecommunications manufacturing – anywhere that medium‑temperature reflow and no‑clean processing are required.

Conclusion

For manufacturers who demand medium‑temperature processing, cost efficiency, and no‑clean convenience, TENSAN TS‑503 is the definitive No-Clean Solder Paste solution. This solder paste offers excellent printability, stable viscosity, clear residue, and proven electrical reliability – all at a cost‑effective low‑silver composition.

By choosing TS‑503, you select a No-Clean Solder Paste that:

• Protects heat‑sensitive components with lower reflow temperatures (210–230°C peak)
• Delivers consistent, fine‑pitch print performance with Type‑4 powder
• Eliminates cleaning steps with no‑clean residue
• Ensures long‑term reliability with high SIR and electromigration resistance
• Meets full RoHS compliance as a lead‑free product
• Reduces material costs with low silver content (0.3–0.5%)

Upgrade to TENSAN TS‑503 – the No-Clean Solder Paste that combines performance, protection, and cost efficiency.

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