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Soft and Hard PCB Soldering Process Discussed

Soft and Hard PCB Soldering Process Discussed

May 25,2022

PCB soldering is an important step in the PCB manufacturing process. Different components are soldered onto the circuit board using employing this process. This soldering is performed using different tools and lead or lead-free solder materials. Although this term is quite popular and well-known to most PCB users and enthusiasts, its underlying processes are rarely discussed. This post introduces you to hard and soft PCB soldering process and more.

An Overview of Soft PCB Soldering Process

The printed circuit boards are available in standard sizes such as 18" × 24", 18" × 12", 9" × 24", and 9" × 12". Nowadays, many applications use large-sized boards with denser configurations. These boards feature several small and fine components, which are soldered onto the board using soft soldering. The small components usually break down at high temperatures because they have small liquefying temperatures. Hence, an extra layer of filler material is added on the board before soldering the component. The filler material made of tin-lead alloy is used for the purpose. The tin-lead alloy has a high liquefying temperature of 752 degrees Fahrenheit. This alloy acts as a binding agent between the board and the component.

An Overview of Hard PCB Soldering Process

This process is distinguished into brazing and silver soldering. In this process, a solid solder is used to join two different elements on the board. The solid solder is melted and allowed to cover the holes, which unlock at high temperatures.

During brazing, a liquid filler is used to connect two terminals on the board. These terminals are usually made of base metals. The liquid filler gets attracted to the vessel through the joints and it creates a strong bond between the component and the board through atomic diffusion and magnetization.

Silver soldering receives its name from the silver alloy used in the process. Generally, cadmium silver is used for the process and it helps fabricate small components to the board easily. Silver soldering is also employed during the board maintenance activities. The silver alloy used for this purpose is usually free-flowing, but it may not be space-filling like tin-lead filler. Thus, a different type of flux is used for creating stronger bonds.

Types of Tools Used for Hard and Soft PCB Soldering Process

Both hard and soft soldering uses similar type of tools. They are:

  • Soldering Iron:

    This tool provides the heat necessary for melting the solder. Soldering irons have a pencil-like tip and possess parts like a wand, solder wick, and rest that work together to form a soldering iron.

  • Solder Flux:

    This is used as a purifying agent in soldering. It works in three ways – purifying and cleaning the components by removing the rust over them, improving the flowing individuality of the solder used for the purpose, and closing any extra air that comes in contact with the material.

  • Soldering Paste:

    This material is used to join the leads of chip packages to connect ends to the PCB.

The choice of soft and hard soldering entirely depends on the type of components used. Partnering with an experienced PCB assembly and manufacturing services provider is always recommended because they know the apt implementation of PCB soldering processes. Creative Hi-Tech is one of the leading PCB assembly and manufacturers in Illinois, USA that has been using advanced PCB soldering processes to deliver robust PCBs. Over the years, the CHTL has invested in state-of-the-art equipment, including SMT and PTH technology equipment, two production lines, and machines for testing and inspection. You can get in touch with the team at the company for more information on PCB assembly and manufacturing services offered by the company.

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