Wave Soldering vs Selective Soldering: Concerns for Manufacturing

April 20, 2021 , in Blog

Building circuit boards essentially requires two-stages: fabrication—or the physical construction of the board architecture—and assembly, where components are added and the PCBA is finalized. The main activity during the latter stage is the soldering of components to the board. The type of soldering depends upon the components utilized. If through-hole technology is used, manufacturers should consider how wave soldering vs selective soldering can impact the time and costs of the optimal board build.

Example of selective soldering

Selective soldering process

Wave Soldering Process

Wave soldering is the original automated PCBA soldering process. As the name implies, the board passes over a wave of solder. Double-sided PCBAs, where components are attached to both the top and bottom surfaces, may require a second pass. This process bonds all components simultaneously. In addition to improved speed, the wave soldering process provides other important advantages:

Advantages

  • Easy setup
  • Rapid process
  • Low costs

However, when deciding whether to institute this process, there are also disadvantages to consider:

Disadvantages

  • Requires more materials-solder, flux, nitrogen and power
  • Certain components necessitate more masking
  • Often results in increased post-assembly cleaning
  • Rework is more common to ensure good solder joint quality

As board size decreased and smaller SMDs proliferated, manufacturers required a more precise soldering process to ensure the solder joint quality of these components. Selective soldering was the answer.

Selective Soldering Process

Selective soldering is a slower process than wave soldering; individual components are soldered sequentially by a local wave on an x-y gantry, as opposed to a full wave which hits all solder joints at once. However, further advantages have propelled selective soldering to become the preferred method in many cases. Several significant advantages offered by the selective soldering process are listed below, as well as a few disadvantages to remember.

Advantages

  • Customizable to accommodate different component parameters such as pitch
  • Masking can be limited to the board areas that need to be soldered
  • No glue needed for SMDs
  • Uses less solder and flux
  • Can be used for special THT cases where size prevents the use of wave soldering
  • Repeatability
  • Does not require applying excessive levels of heat to board areas that may be more sensitive to high temperatures

Disadvantages

  • Complex setup
  • More time-consuming than wave soldering
  • Not efficient for mass production

Selective soldering can offer an advantageous process for many scenarios—especially for today’s small, densely packed boards.

Comparing Wave Soldering vs Selective Soldering

The decision to apply wave soldering vs selective soldering reflects a process choice between efficiency and flexibility—provided that your CM is able to institute both. Selected attributes of each process are described more fully in the table below.

WAVE SOLDERING VS SELECTIVE SOLDERING
Attribute Wave Soldering Selective Soldering
Setup Simple Complex
Material requirements More Less
Need for rework More likely Less likely
Repeatability No Yes
Cleaning Additional Less
Speed Faster Slower
Cost Less More

As the table above indicates, each method has its advantages. For example, manufacturers can realize significant cost savings by using wave soldering for high-volume production. Alternatively, for prototyping and low-volume manufacturing of complex boards, selective soldering can provide a more cost-efficient process.

Tempo’s Software-Driven Smart Factory Delivers the Industry’s Leading Custom Turnkey PCBA Manufacturing Services
  • Virtual PCBA Contract manufacturing.
  • Rapid, accurate quotes.
  • DFM support from Day 1 of design.
  • Digital Thread Processing with real-time monitoring.
  • Fastest turnaround times in the industry to maximize ROI.
  • QC certified Agile Manufacturing process to support risk management.
  • Standard and Advanced QC testing.
  • Worry-free supply chain continuity.
  • Specialization in rapid prototyping and low-volume production.
  • PCBA development optimization for complex critical system industries like Aerospace, Medical Devices, Automotive, and Industrial.

Tempo Automation, the industry leader in building fast, precise, complex boards for prototyping and low-volume production, utilizes advanced selective soldering to ensure secure solder joints and the highest overall quality for your boards.

And to help you get started on the best path, we furnish information for your DFM checks and enable you to easily view and download DRC files. If you’re an Altium Designer or Cadence Allegro user, you can simply add these files to your PCB design software. For Mentor Pads or other design packages, we furnish DRC information in other CAD formats and Excel.

If you are ready to have your design manufactured, try our quote tool to upload your CAD and BOM files. If you want more information on wave soldering vs selective soldering, contact us.

The latest PCB news delivered to your inbox.

Search Sign In
[[]
[[]
[").replace(/[]]
[").replace(/[]]
[?&]
[?&]
[^&#]
[^&#]
[name="email"]
[name="email"]
[w-.]
[w-.]
[w-]
[w-]