Today's electronics manufacturers face a key decision: choosing the right lead-free solder for their specific application. While traditional leaded solder remains an option, many are making the switch to lead-free alternatives. Let's explore the main lead-free options to help you select the best one for your needs.
Understanding Lead-Free Solder Properties
Lead-free solders require higher melting temperatures and behave differently in terms of wetting and spreading compared to leaded alternatives. While this can impact production speed and tip wear, understanding each option's characteristics helps you make the right choice.
Popular Lead-Free Solder Options
SAC 305 (Tin-Silver-Copper)
- Composition: 96.5% tin, 3% silver, 0.5% copper
- Best for: PCB Assembly and general electronics
- Advantages: Excellent thermal properties, mechanical strength, and reliability
- Industry standard for lead-free PCB assembly
Tin-Copper
- Copper content: 0.7% to 3.0%
- Best for: General electrical work and electronics
- Advantages: Good wetting properties, reliable joints
- Cost-effective alternative to silver-containing alloys
Tin-Silver
- Best for: Applications requiring high thermal conductivity
- Advantages: Superior thermal performance and reliability
- Note: Higher cost due to silver content
Tin-Bismuth
- Best for: Low-temperature applications
- Limitations:
- Challenging to produce in small diameters
- Lower strength compared to other options
- More brittle composition
Making Your Selection
When choosing a lead-free solder, consider:
- Your maximum temperature constraints
- Required mechanical properties
- Budget considerations
- Production volume and speed requirements
Each type offers distinct advantages, and the best choice depends on your specific manufacturing requirements and constraints.
Below are common lead-free solder alloys and their melting point temperatures:
SOLDER ALLOY |
SOLIDUS °F |
LIQUIDUS °F |
SAC 305 (96.5/3.0/0.5) |
423 |
426 |
99.3 Sn/0.7 CU |
441 |
441 |
97 Sn/3 CU |
441 |
590 |
96.3 Sn/ 3.7 Ag |
430 |
430 |
42 Sn/57.6 Bi / 0.4 Ag |
281 |
284 |
63 Sn / 37 Pb Tin /Lead | 361 | 361 |
Which Lead-Free Solder is Easiest to Use When Hand Soldering?
When hand soldering, the best lead-free solder should be one that has a lower melting point as well as silver for strength. Therefore, the SAC 305 and the 96.3/3.7 alloy Tin/Silver would be best if your budget allows it.
Still not sure? Send us an email or speak to one of our Customer Service team to figure out which is best for what you're building.