Wave-soldering

for thousands of joints per minute.

SOLUTIONS with Effective, Practical Advice

Making Connections on Electronics Boards

Brazing Problem? Solve it! with
Help from a Welding Professional
Contact Us.

Note: To view Google Ads, Pls.
Right Click and
Open in a New Window.

Wave-soldering is an automatic soldering process for printed circuits.

These are passed through a wave or fountain of molten filler solder, created by a pump at the bottom of the solder tank.

It is a unique method suitable for special cases.

For the process in general see our page on Soldering.

Boards Mass Production with Wave-soldering

It is essentially one of the major techniques used for mass production of electronic boards.

Printed wiring boards (PWB) or Printed circuit boards (PCB) assure electrical contacts using through hole connections and/or surface mount devices.

Wave-soldering is therefore highly automated to assure the highest productivity measured in thousands of soldered joints per minute.

In practice a pump located at the bottom of the heated tank, generates on the free liquid surface a fountain of molten solder, or waves precisely designed to lap the bottom side of the boards moving on a conveyor.

As the passing printed circuit boards meet the wave, the solder wets the metal leads and terminations, and fills the holes, establishing electrical contacts between the different elements. The board is in contact with the solder wave for about 5-7 sec.

The boards are kept on the conveyor at a slight slant, to ease the draining of excess solder back to the solder pot.

Note: To view Google Ads, Please
Right Click and
Open in a New Window.

Integrated units for Wave-soldering are built to perform all the required operations:

  • Flux application either as a liquid or as a foam spray,
  • board preheating,
  • wetting by the solder wave,
  • natural or accelerated cooling.

It is impractical to inspect the single joints manufactured by Wave-soldering, and even less to repair faulty joints, given the huge quantities produced.

Quality Control Procedures are based therefore on solderability tests and on lot sampling providing acceptance/rejection statistics.

The design must be accurate enough to permit actual wetting of the clean and fluxed metal surfaces and to avoid too large gaps.

Different techniques are applied depending on whether the surface devices are dipped in the wave or kept outside.

Besides missed joint soldering named "skips", other joining defects are called bridges, or unwanted shorts caused by solder deposits between near by conductors, and icicles, solder drops hanging from metal surfaces.

Process parameters for Wave-soldering must be carefully established and monitored because they are critical to the success of the whole operation.

Both the flux condition, likely to deteriorate because of accumulation of contaminants washed out from the large number of passing boards, and the application parameters must be closely followed and corrected when necessary.

The solder wave shape and properties are of fundamental importance to the success of the operation.

The entrance zone of the wave has to be mildly turbulent to ease the reaching of all joints and the escape of volatile parts of the flux that may cause voids.

The main part of the wave supplies the needed heat to promote wetting of the substrate elements.

The exit region (the last contact between the solder wave and the board) should be calm and smooth, possibly by reducing the speed difference between the board and the wave, to prevent formation of bridges and icicles.

Dross formation on the solder surface may be lowered by reducing solder temperature (if possible), by using a protective atmosphere or by covering it with suitable oils.

Wave-soldering uses higher than usual molten solder temperatures to provide sufficient heating of the substrate>

This is needed for improved wetting and for reducing the viscosity in the separation or peel-back region to minimize defects formation.

Contamination of the solder with prolonged use must be checked and kept under control, as its physical properties may change with composition bringing about unacceptable results.

The composition of the solder filler metal is currently under scrutiny as the presence of lead has been banned, for health and environmental reasons.

Practically all parameters must be optimized and kept under strict control, with severe limits on the maximum contamination allowable.

Conditions include composition of filler and of flux, temperatures at the different positions along the Wave-soldering process path, times of preheating, of contact and of cooling.

An Article on Filler Metals Reliability of Solder Joints was published (4) in Issue 164 of Practical Welding letter for April 2017.
Click on PWL#164.

You may wish to watch the following Videos illustrating the process introduced in this page.

1 - PC Board Assembly - Wave Soldering Machine
2 - Circuit board assembly at SMA's German factory

1 - http://www.youtube.com/watch?v=inHzaJIE7-4
2 - http://www.youtube.com/watch?v=2qk5vxWY46A

* * *

Any questions or comments or feedback? Write them down and send them to us by e-mail. Click on the Contact Us button in the NavBar at top left of every page.

Hardness Testing
made simple Let us remind you that, if you are interested, we offer a no cost subscription to our Practical Welding Letter and a bonus book in pdf format to be made available for download to your computer on the subject of
PRACTICAL HARDNESS TESTING MADE SIMPLE. Click on Subscription.

To reach a Guide to the collection of the most important Articles from Past Issues of Practical Welding Letter, click on Welding Topics.

Note: To view Google Ads, Please
Right Click and
Open in a New Window.

Back Home
Processes
Site Map

Metals Knowledge
Friction Welding Processes
Friction Stir Welding
Flash Welding Process
Stud Welding
Upset Welding
Resistance Welding Processes
Projection Welding
Gas Welding Processes
Arc Welding Processes
High Energy Welding Processes
Micro Welding Processes
Additional Processes
Cold Welding
Ultrasonic Welding
Explosion Welding


If you did not yet find what you need, why not typing your question in the following Search Box?


How can you solve
your Welding Problems?

Click on Welding Consultation and
Metallurgical Expertise.

Wave-soldering Top



Watch the following video...

Click on the following image to watch the SBI! TV Show!

SBI TV Show

BUILT BY:

Solo Build It!

Click on this Logo NOW!


Watch - The Video:

Why Don't I Work From Home?

and also

Think outside the Cube.

Follow this Invitation!

Experience C2 power and flexibility in action by clicking SBI! 2.0 For You.
Where SBIers share their business-building experiences first-hand.
You will realize that there is nothing comparable to SBI! when you read
real stories from SBIers who share how C2 has helped them
expand, accelerate, build trust and monetize their sites.

Copyright (©) 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017
by Elia E. Levi and www.welding-advisers.com
All Rights Reserved

SBI!