The Pros and Cons of Using Lead-Bearing Solder Paste

With electronic engineering booming worldwide, there is continuous R&D efforts being put into the techniques and methods used for highly mechanized mass-production of printed circuit boards. This process can be daunting if the prerequisites are not falling in place. One such process is soldering, where solder paste, solder bars (or solder wire) and other electronic materials are used to manufacture high quality printed circuit boards. There are lead based and lead-free solder pastes used for PCB assembly. Here, in this blog, we will focus on the pros and cons of using lead solder paste for manufacturing of printed circuit board.

Pros -
1.    Lead-bearing solder paste has a low melting point, making it easy to form the joint nicely without damaging the parts of the circuit board.
2.    Because of low melting points, less heat is needed to get the job done, thus consuming less energy and indirectly helping you save on energy bills.
3.    Due to the advantage of the viscosity of lead solder paste, different types and kinds of solder paste can be formed depending on the particle size, shape and flux.

Cons –
1.    Lead is toxic, thus lead based solder pastes used for electrical connections are harmful for humans and for the environment.
2.    Joints attained by lead solder paste are weaker as compared to lead-free solder paste.
3.    Lead solder paste is a poor conductor of heat and hence a large percentage of the joint mass demonstrates electrical resistance.

With this evaluation of the pros and cons of using lead solder paste, it might be easy for you choose the best for your PCB manufacturing requirements.

How to Choose the Best Low Temperature Soldering Paste?

A solder is the most essential part of soldering process for manufacturing printed circuit boards. It has been invented for creating permanent electrical connections between various electronic components. Simply put, solders are fusible metal alloys consisting of different elements and combinations which are then used in different electronic device manufacturing applications. The right kind of solder paste helps to join two metal pieces during the PCB assembling process, and creates a stable bond between the different metal pieces. The most essential part is that these solder alloys are to be used in the right combination and at the right temperature as per the specifications of the printed circuit board being assembled. Let’s see how one can choose the right low temperature solder paste for their requirements.

Solder paste is made up of alloys comprising mostly of tin these days. Low temperature solders are easily fusible at temperatures generally below 200 degrees °C. The alloy you choose should take into consideration the chemistry of the surfaces to be joined and the alloy itself. Any adverse reaction should not be taking place at the selected temperature range.

# Unless otherwise stated in the PCB specifications, low temperature solder paste should be lead-free as per the latest norms notified by various authorities, as lead is a toxic metal, and can harm humans when absorbed through the skin. Even trace amounts of this metal can result in terminal health issues.

# Selecting the right low temperature solder paste also depends on the thickness of the board and the density of the alloy. Some printed circuit boards need to be manufactured with extremely thin widths on which high temperatures may have adverse effects.

Just keep these factors in mind and make the best selection of low temperature solder paste for your PCB assembly.