TENSAN mid-temperature lead-free solder paste is formulated with Sn-Ag1-Bi35 alloy, offering a unique melting point profile ideal for heat-sensitive components and multi-step reflow processes. This solder paste delivers excellent printability, low residue, and reliable soldering performance at lower peak temperatures than standard SAC alloys. With Type 4 powder size and ROL1 flux classification, this mid-temperature solder paste is the preferred choice for consumer electronics, automotive modules, and LED lighting assemblies where thermal management is critical.
Mid-Temperature Lead-Free Solder Paste with Bi35 Alloy – TENSAN for Heat-Sensitive SMT Assembly
In modern electronics manufacturing, not all assemblies can withstand the high peak temperatures required by standard SAC305 solder paste. Heat-sensitive components, flexible PCBs, and multi-step reflow processes demand a solder paste that can form reliable solder joints at lower temperatures without compromising quality.
TENSAN mid-temperature lead-free solder paste is engineered to meet this exact need. Formulated with a Sn-Ag1-Bi35 alloy, this solder paste delivers excellent wetting and soldering performance at a significantly lower melting point than conventional SAC alloys, protecting thermal-sensitive components while maintaining production efficiency.
What Is TENSAN Mid-Temperature Lead-Free Solder Paste?
This product is a lead-free, no-clean solder paste designed for SMT assembly processes that require:
Key Specifications
Alloy Composition & Physical Properties
|
Parameter |
Specification |
|
Alloy Composition |
Sn-Ag1-Bi35 |
|
Alloy Components |
Sn (balance), Ag (0.9–1.1%), Bi (34.5–35.5%) |
|
Powder Size |
Type 4 (20–38 μm) |
|
Flux Content |
10.5 ± 1.0% (wt%) |
|
Viscosity (25°C, 10 RPM) |
140 – 190 Pa·s (Malcom Viscometer) |
|
Packaging |
500 ± 5 g per jar |
|
Shelf Life |
6 months (stored at 5–10°C) |
|
RoHS Compliance |
Yes |
|
Test Item |
Result |
Standard Reference |
|
Flux Classification |
ROL1 |
IPC J-STD-004 |
|
Halogen Content |
< 1500 ppm |
EN 14852:2007 |
|
Copper Mirror Test |
PASS |
IPC J-STD-004 |
|
Copper Corrosion Test |
PASS |
IPC J-STD-004 |
|
SIR (85°C/85% RH, 7 days) |
PASS, > 1.7 × 10⁹ Ω |
IPC J-STD-004 |
|
SIR (Bellcore, 65°C/85% RH, 96 hrs) |
PASS, > 6.4 × 10¹² Ω |
Bellcore GR78-CORE |
|
Electromigration (65°C/85% RH, 10V, 500 hrs) |
PASS – final 1.17 × 10¹⁰ Ω |
Bellcore GR78-CORE |
Physical Properties
|
Test Item |
Result |
Standard Reference |
|
Residue Color |
Clear / Transparent |
– |
|
Adhesion (8 hrs @ 25°C/75% RH) |
PASS, change < 1 g/mm² |
IPC J-STD-005 |
|
Adhesion (8 hrs @ 25°C/50% RH) |
PASS, variation < 10% |
JIS Z 3284 |
|
Solder Ball Test |
Acceptable |
IPC J-STD-005 |
|
Viscosity Hold Time on Stencil |
> 8 hours (@ 50% RH, 22°C) |
– |
Test methods conform to IPC J-STD-004, IPC J-STD-005, JIS Z 3284, and Bellcore GR78-CORE standards.
Why Choose TENSAN Mid-Temperature Lead-Free Solder Paste?
1. Unique Bi35 Alloy for Lower Reflow Temperatures
This solder paste lead free formulation provides the reliability of SAC alloys at a more forgiving temperature profile.
2. Excellent Print Performance with Type 4 Powder
With Type 4 powder size (20–38 μm), TENSAN mid-temperature solder paste delivers:
Whether you use a solder paste printer with automated settings or manual printing equipment, this solder paste adapts to your process requirements.
3. No-Clean, Low-Residue Formulation
This solder flux system is designed to leave clear, non-conductive residue that:
The no-clean design makes this product ideal for high-volume production where efficiency is paramount.
4. Long Stencil Life and Stable Viscosity
TENSAN mid-temperature solder paste maintains consistent viscosity for:
This stability ensures that your solder paste printer operates at peak efficiency with minimal interruptions.
5. Excellent Wetting and Solder Joint Quality
Despite its lower melting point, this snagcu solder paste (Sn-Ag-Bi system) provides:
Recommended Application Parameters
Stencil Design Guidelines
|
Component Type |
Recommended Aperture Reduction |
Aspect Ratio (Width/Thickness) |
|
Discrete Components |
10 – 20% reduction |
≥ 1.5 |
|
Fine-Pitch Components (≤ 0.5 mm) |
5 – 15% reduction |
≥ 1.5 |
Printing Conditions
|
Parameter |
Recommended Setting |
|
Printing Speed |
25 – 100 mm/s |
|
Squeegee Pressure |
0.020 – 0.027 kg/mm blade length |
|
Roll Diameter |
20 – 25 mm |
|
Wiping Frequency |
Every 10 – 25 prints |
|
Stencil Life |
> 8 hours @ 22–28°C, 30–60% RH |
|
Ambient Temperature |
22 – 28°C |
|
Ambient Humidity |
30 – 60% RH |
|
Process Parameter |
Recommended Value |
|
Preheat Rate |
1 – 2°C/s |
|
Soak Temperature |
150 – 180°C |
|
Soak Time |
60 – 120 seconds |
|
Peak Temperature |
210 – 230°C |
|
Time Above Liquidus |
40 – 60 seconds |
|
Cooling Rate |
≥ 2°C/s (forced cooling recommended) |
Note: The lower peak temperature of this mid-temperature 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.
Recommended Temperature
Storage and Handling Guidelines
|
Step |
Action |
|
Storage Temperature |
5 – 10°C (do not freeze) |
|
Room Temperature Storage |
Up to 15 days |
|
Warm-up Time |
4 hours minimum at room temperature (sealed) |
|
Mixing Duration (Manual) |
3 – 6 minutes |
|
Mixing Duration (Machine) |
1 – 3 minutes with solder paste mixer |
|
Resealing |
Immediately after each use; replace liner if seal is compromised |
Important: Do not mix leftover paste with fresh paste in the same container. Always warm up this solder paste in its sealed container to prevent moisture condensation, which can cause spattering during reflow.
Solder Paste Composition Overview
Alloy Chemistry (Mass%)
|
Element |
Content |
CAS No. |
|
Sn (Tin) |
Balance |
7440-31-5 |
|
Bi (Bismuth) |
34.5 – 35.5% |
7440-69-9 |
|
Ag (Silver) |
0.9 – 1.1% |
7440-22-4 |
|
Impurities (Total) |
< 0.1% |
– |
Typical Applications
TENSAN mid-temperature solder paste is ideal for applications requiring lower reflow temperatures:
Frequently Asked Questions
Q: What makes this mid-temperature solder paste different from SAC305?
A: This solder paste composition includes 35% bismuth, which lowers the melting point. This reduces thermal stress on heat-sensitive components and supports step-soldering processes.
Q: Is this solder paste compatible with standard solder paste printers?
A: Yes. This solder paste type 4 is compatible with all standard SMT printing equipment.
Q: Do I need to use a specific solder paste mixer for this product?
A: A standard planetary or centrifugal solder paste mixer is recommended for 1–3 minutes to ensure uniform mixing after cold storage.
Q: What is the solder paste type for this product?
A: This product uses solder paste type 4 (20–38 μm powder size), suitable for fine-pitch printing.
Q: Can this product be used for nitrogen reflow?
A: Yes, it performs well in both air and nitrogen reflow environments.
Q: Is this solder paste RoHS compliant?
A: Yes, this solder paste lead free product fully complies with RoHS Directive requirements.
Conclusion
For manufacturers dealing with heat-sensitive components, flexible substrates, or multi-step reflow processes, TENSAN mid-temperature lead-free solder paste offers the ideal solution.
This mid-temperature solder paste delivers:
By choosing TENSAN mid-temperature lead-free solder paste, you achieve reliable soldering results while extending component life and reducing thermal defects.
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
For alternative alloys or custom packaging, please contact your local TENSAN sales office.
