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PCB Soldering - Wave Soldering vs Reflow Soldering

October 18, 2021

PCB Soldering - Wave Soldering vs Reflow Soldering

Soldering is an essential process in constructing printed circuit boards (PCBs). Two of the most common methods of soldering PCBs are wave soldering and reflow soldering. These methods both have their advantages and drawbacks, and deciding which one to use depends on various factors, such as cost, production volume, and the type and size of the PCB.

Wave Soldering

Wave soldering is a through-hole technology that uses a wave of molten solder to transfer to the PCB to create solder joints. First, the PCB is coated with a flux to clean and prepare the surface for soldering. The PCB is then passed over a wave of molten solder, which mechanically applies the solder to the through-hole and surface-mount components. The excess solder is then removed by a mechanism called vacuum extractors.

Advantages of Wave Soldering

  • Suitable for high-volume production of PCBs: wave soldering is ideal for large-scale production due to its high throughput.
  • Cost-effective: wave soldering machines have a lower upfront cost compared to reflow soldering machines.
  • Works well with through-hole components: wave soldering is the preferred method for through-hole components as it ensures complete solder penetration.

Disadvantages of Wave Soldering

  • Temperature limitations: wave soldering cannot be used for temperature-sensitive components or PCBs with varying solder requirements as the process relies on a consistent wave of high-temperature solder.
  • Not suitable for fine-pitch components: wave soldering cannot effectively solder surface-mounted, fine-pitch components or components with tight spacing.

Reflow Soldering

Reflow soldering is a surface-mount technology that applies paste solder onto a PCB to create solder joints. The paste contains metal particles that form the solder alloy when heated. The PCB is then passed through a conveyor oven, which causes the temperature to rise and melt the solder paste. The solder paste solidifies as it cools to create a sturdy solder joint.

Advantages of Reflow Soldering

  • Suitable for fine-pitch components: reflow soldering is the ideal method for surface-mounted and fine-pitch components or PCBs with a tight spacing layout.
  • Versatile: reflow soldering works well with a wide range of components, including Quad Flat No-Lead (QFN) packages and Ball Grid Array (BGA) components.
  • Precise and accurate: reflow soldering is a controlled process that ensures consistent and accurate solder joints.

Disadvantages of Reflow Soldering

  • Not suitable for high-volume production: reflow soldering has a lower throughput than wave soldering, making it unsuitable for high-volume production.
  • Higher production costs: reflow soldering machines have a higher upfront cost compared to wave soldering machines.

Conclusion - Wave Soldering vs Reflow Soldering

In summary, both wave soldering and reflow soldering have their advantages and limitations. The chosen method depends on the type of the PCB, the components used, and the production volume required. Wave soldering is the preferred method for through-hole components and high-volume production due to its high-throughput and lower upfront cost. Reflow soldering is the ideal method for surface-mounted and fine-pitch components, and precise and accurate solder joints.

We hope this comparison helped you make an informed decision on which method to use for your next PCB project.

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