Blog  /  The Ultimate Guide to PCB Solderability Test and Functionality

The Ultimate Guide to PCB Solderability Test and Functionality

In the manufacture of PCBs, two things matter the most: the product’s quality and the choice of PCB materials. If you want to ensure that PCB production runs well, then some tests are necessary. As a manufacturer, you need to reduce PCB failures to ensure that you raise your final product’s quality levels. Among other types of tests, the solderability test tops the list.

As a practitioner in the PCB industry, you need a clear understanding of the specific processes of solderability testing. By going through this article, you’ll understand much to do with solderability testing, problems it can solve, and its operation process, to mention but a few. Below is what you need to know about the solderability test.


1. What is the PCB Solderability Test?


The solderability test determines the solderability of terminals and leads through a specific soldering operation. Solderability measures how perfect or imperfect the metal is wet by molten solder to secure all connections.

Evaluating solderability tells your PCB tester whether the attached parts, such as terminations and leads, can withstand high temperatures. High temperatures may occur during welding. Tests also determine whether these components’ storage will adversely affect their ability to solder to circuit boards.

Understanding matters to do with PCB solderability tests can significantly minimize board failures while improving the product’s final quality. In short, solderability is the molten solder’s ability to maintain a uniform liquid state unbroken and even during the soldering process.


2. The Primary Types of Solderability Tests


There are three primary types of solderability tests. They include the following:


“Immersion” approach


This method also goes by the name Dip and Look. The “immersion” approach subjects the termination and leads up to 8 hours of steam conditioning. The steam conditioning is over; what follows is the dipping of components’ termination into the solder. This factor accelerates the aging process. Finally, inspection follows to ensure that they meet the required standards.


The surface mount simulation test 


It is another primary type of solderability test. It’s available for all SMT components, such as those that aren’t compatible with other types of PCB test methods, such as the “immersion” approach.


Wet balance analysis


Lastly, there’s wet balance analysis, a type of test that ages the circuit board components. Here, the testers get to plot the wetting force, beginning at negative (non-wet).


SMT simulation test

(SMT simulation test)


3. Equipment and Tools Needed for the Solderability Tests


The right tools and equipment are one of those factors which will see you staying relevant in a competitive environment.

Without a doubt, one of the essential tools that you must have is the soldering iron. A soldering iron provides the heat source to melt the solder. But again, the soldering iron doesn’t need to be expensive as such. If you look around, you’ll find some that go for as little as $10.

Besides the soldering iron, other tools that you may need during soldering include the following:


Solder Flux 


The Solder Flux acts as a purifying agent, and it purifies the components while closing out extra air to prevent rust. The Solder Flux is one of the essential tools to have at hand when soldering. Manufacturers love it as it goes further to better the dripping individuality of the solder itself.


Solder Paste  


Solder Paste joins various leads of chip packages to connection ends of boards. The solder paste appears like a gray putty-like substance. During soldering, the paste joins the multiple charges of chip packages to the connection ends on a PCB.


Solder suckers 


Solder suckers also go by the name solder pumps. These mechanical vacuum pumps suck solder away from solder joints. They enable the removal of solder from a joint for components desoldering for rework.


Wire cutters 


Even though they tend to be small, wire cutters are convenient tools. You can use the wire cutter to cut off long component legs. Also, you can use these wire cutters to strip the end of the wires. Wire cutters again go by names such as diagonal cutters, flush-cutters, clippers, electronic snippers, and more.


Soldering iron tip cleaner  


Soldering tip cleaners are necessary during soldering. They are for cleaning iron tips from any old solder or carbon accumulation. If you want your soldering iron to last for long, then you’ll need soldering iron tip cleaners.


Desoldering Wick 


Manufacturers use this to clean the leftovers of solder that remained behind during soldering. A desoldering wick is a finely braided copper wire. The copper wire has a rosin coating flux that can finely remove excess copper.


Circuit board holder 


It is the perfect equipment for holding the PCB into place during soldering. Some refer to this equipment as a soldering helping hand and comes in handy when soldering adequate equipment. The circuit board holder fixes the objects at the required angles for soldering.


The Printed Circuit Board 


Of course, you’ll need a printed circuit board where your components will sit. Depending on your project’s needs, the circuit board could be rigid, flexible, or rigid-flex.

The above isn’t all the tools that you’ll need. Others you may find ideal include Soldering Iron Stand, Preheaters, Thin nose pliers, etc. Depending on your project’s size, you may find yourself requiring more tools and equipment than you imagined. If the project is somewhat DIY, then the tools needed may not be too many and detailed.


A close pic of solderability equipment

(A close pic of solderability equipment)


4. The Importance of PCB Solderability Tests


Solderability test on a printed circuit board is critical. If you fail to undertake some tests, then you are inviting trouble. There’s nothing riskier and expensive than rolling out faulty boards to the market. You can avoid such by only undertaking solderability tests. So what’s the importance of the PCB solderability test? Here they are:


Evaluation of PCB coating, solder, and flux 


Solderability tests ensure that you assess the quality of your coating, solder, and flux before introducing them to the market. Having great coating solder and flux will give the end-user ample time during repairs while also ensuring the product is long-lasting.


Perform quality control  


Solderability tests confirm that there’s quality control of the circuit boards that PCB manufacturers make. By doing so, manufacturers ensure that they produce high-quality products that meet customer satisfaction.


Reduce assembly problems, including misapplication of solder mask 


During assembly, problems are likely to occur. Some of the typical assembly problems include insufficient copper-to-edge clearance and lousy soldering. Others include the misapplication of the mask, the solder mask, and non-wetting challenges. Fortunately, though, such isn’t the case with solderability tests. Manufacturers that get to undertake solderability tests will realize reduced assembly problems, an aspect that gives them an edge over their competitors.


Improve the possibility of reliable solder joints 


In the field of electronics, the quality of the solder matters a lot. Therefore, with poor solder joints, then the transmission of signals from one point of the board to the next would almost be impossible.

Reliability in solder joints is necessary for the proper functionality of the whole board. These tests point out faulty solder joints that need attention, thereby bringing out the possibility of having reliable solder joints.


Verify secure storage 


It’s essential to store these circuits within the shortest time possible as means of reducing possible damages. Solderability tests are crucial here because they help verify that suppliers meet solderability requirements. They help in proving that storage conditions don’t degrade solderability. With solderability tests, it’s easy to estimate some of the long-term effects that accompany storage.


The process of PCB solderability

(The process of PCB solderability)


5. Advantages of PCB solderability tests


Check all openings in the designated area. 


A circuit board must have openings at some places. These openings play different roles, such as transmitting current to other sites on the board. Solderability tests are advantageous as they check if all the spaces on a board’s designated area are there. Without solderability tests, then it would be challenging to review the entire openings on board.


A comprehensive inspection of solder residue 


With solderability testing, you get to inspect all the solder residue left on the board upon completing the soldering process. Even though it is typically hard for manufacturers to thoroughly check for the residues during production, you can’t avoid the tests’ inspections. Removing the excess solder residue improves the board’s quality and appeal and makes it easy to operate during repairs.


Measure surface tension 


Solderability tests are ideal ways of measuring a boards’ surface tension. Even though many circuit manufacturers use dyne pens, solderability tests are also suitable for measuring surface tension.


Reduce the risk of damaging thermal components 


There’s nothing worse than damaging the thermal components of your circuit board. Such may end up being a very costly affair that will see you spending unnecessary costs. However, such isn’t the case when it comes to solderability testing. Here, the parts undergo soldering for short periods. Such will end up reducing the risk that comes up with damaging heat-sensitive components.


Solderability can save costs. 


Without a doubt, solderability is much easier and less costly for manufacturers to prevent poorly soldered boards from reaching full production.


High-quality solderability-tested boards

(High-quality solderability-tested boards)


6. Is the solderability tests required for all PCB projects?


There are plenty of printed circuit board projects out there. Some are for hobbyists and DIY enthusiasts, while others are professional and meant for big projects. Some apt examples of PCB electronic projects for beginners include:


Fridge Door Alarm 


It is one of those simple PCB projects. It can detect and subsequently inform the status of the refrigeration unit’s door. If the door is open for long, then there’s the production of a long and monotonous beeping noise.


DIY Clap Switch Circuit 


It is a simple electronic circuit known for making use of dynamic control application by use of sound. It’s relatively easy to understand and cheap to create.


Music Reactive LED Circuit 


This device responds to rhythmic changes of any musical instrument. They are suitable for those starting in the world of PCBs.


Electronic Piano Printed Circuit Board 


The electronic piano is also a simple based PCB project. This piano tends to produce a melodic sound with every press of a button.


Call Detector Printed Circuit Board 


The call detector PCB can easily detect the presence of any nearby RF transmitting mobile device nearby. It can also provide easy alerts concerning it.


Crystal Testers 


They play the role of oscillators aimed at generating high frequencies. In major electronic projects, crystal finds heavy usage as opposed to coils. Here, the use of PCBs is also every day.


Battery Voltage Monitor 


This one monitors the charging and discharging of the battery. It makes sure that the battery voltage does not exceed the specified level. Again, the use of PCBs is evident here.

The above does not constitute the entire beginner projects that may require the use of printed circuit boards. There are plenty of other beginner’s/DIY projects where the use of printed circuit boards finds heavy use.


Is this test necessary?


Regardless of the project at hand, solderability tests are necessary. As mentioned earlier, solderability is more of a cost-saving mechanism. It also reduces the risks of damaging the internal components and ensure that the members have a stable electrical contact—professionals and DIY alike need to ensure that they subject all their projects to solderability tests.

Based on the advantages above and the importance of solderability tests, no project needs to ignore such tests. In short, solderability tests are ideal for all PCB projects. Without them, manufacturers may end up rolling out faulty boards that aren’t fit for market use.


Professional PCBs under solderability test

(Professional PCBs under solderability test)


7. Can you afford the price of the solderability tests?


Do you think that the cost of the solderability test is cheap? If so, then you are in for a rude shock. The price of undertaking solderability tests is relatively high, especially if you are starting. Most printed circuit board designers give up way before they even venture on their projects.

For instance, looking around, you’ll notice that solder paste doesn’t come cheap as you may imagine. The cheapest ones go for about $100, and that’s just a single pound roll. If you seek such services from PCB makers, then rest assured of high solderability costs. Besides the solder paste, the soldering station is also expensive. While you may think of sourcing them cheaply from offshore countries, still, you’ll have to pay huge shipping costs.


Solderability tests–The high cost of equipment 


Soldering equipment doesn’t also come relatively cheap. For instance, some of the most affordable and mostly low-quality soldering irons go for $10. How about the best ones in the market then? Most of them are so expensive, with manufacturing affording them. That’s not all when it comes to solderability expenses. The cost of repairing errors occurring during the soldering process is also high.

As you can see from above, solderability tests are slightly a costly affair. But that doesn’t mean that you cannot afford it. You can suit your needs depending on your budget. If you are on a budget, then you can go for cheaper tests.


A highly expensive multi-layer PCB

(A highly expensive multi-layer PCB)




Now more than ever, we cannot ignore the importance of solderability testing, especially across the circuit board industry. Solderability comes with many benefits, such as the ones mentioned above. We at OurPCB understand the importance of solderability testing. We have the equipment to do such tests with ease.

Better yet, it doesn’t have to be expensive on your end. We can have a discussion and meet in the middle. Do you have any upcoming PCB solderability test needs? We can help you with such in addition to more PCB production. Call us today for a discussion about what you need to know about solderability testing and PCB production.