Cold Solder Joints: Everything You Need To Know in 2022


One of the essential phases of producing and assembling a circuit board is soldering. However, there are instances that it promotes the occurrence of problems.

It is referred to as Cold Solder Joints; this can significantly affect the product’s performance to a greater extent. Also, it could potentially increase the cost of the assembly moderately.

Do you have experience with links that have cold solder owing to insufficient thermal treatment? Do you know how to manage this issue or how to spot, stop, cure, and restore it?

All of these will be tackled in this blog, starting with its causes and solutions. Keep on reading until the end for a better understanding of this topic.


Introduction to Cold Solder Joints

What is Cold Solder Joint?

If something isn’t appropriately heated and fails to melt as it should, it is regarded as Cold Solder Joint. It forms convex-like shapes into its pins and the versatile portion of the board.

They can sometimes appear coarse and sluggish. This issue occurs if you don’t warm the solder thread to the necessary degree before joining. Furthermore, cold solder joints can be caused by unwelcome disturbances in the PCB and solder once they solidify.

Also, dielectric properties don’t consider cold joints’ impact particularly appealing. Cold junctions’ increased solder susceptibility hampers the current flow among PCB components. The circuit board can stop conducting electricity if the solder connection gets too cold. That implies that in that situation, you must upgrade the panel.

Additionally, since the materials are not securely linked, these junctions cannot withstand resonance. As interconnections with cold solder, even erratic temperature changes might severely impact them.

Nevertheless, cold solder joints don’t occur naturally; they result from substandard production. Thus, we suggest going for experienced and skilled manufacturers to avoid such.

Different Types of Cold Solder Joints

When contacting a circuit board, different cold solder junctions are noticeable. Each of these physically and electronically weak solder junctions has unique impacts and fixes.

To make things easier, we’ve listed the most popular cold solder joints below.

Different Types of Cold Solder Joints

Types of Cold Solder Joints

Distributed Cold Joints

Often the soldering iron begins to move when the solder alloy is deposited on the specific area of the PCB. The term scattered cold solder joint refers to this phenomenon; a hollow form, a pointed pin, crystals, etc., can be used to identify it.

The most significant source of dispersed cold solder joints is the motion of the PCB. This problem can be deliberately avoided if PCB mobility can be stopped. Maintaining the circuit board on an adequately positioned soldering clamp or PCB adapter allows you to execute the soldering process. When operating, it aids in keeping the PCB’s stability.

Cracked Solder Joint

Unsatisfactory solder or mechanical forces can cause some cold solder joints to break. In this situation, the element pin falls loose, completely disregarding the electrical transport circuits.

Typically, the weight of the PCB pieces causes the gravitational forces that cause damaged solder junctions. Vertically placed components usually result in high gravity and cracked solder junctions. This breaking could worsen if the circuit board experiences stress or flipping.

One should be aware that not all broken solder junctions are cold joints. However, if neglected, they can lower the circuit board’s productivity.

Dry Solder Joint

In PCB-based electrical appliances, this is yet another type of cold solder link that can be found. The most significant source of dry solder junctions is a lack of solders. There is not enough iron in these joints. They experience open connections as a result, which causes various mishaps.

The electrical potential and erratic current flow that dry links encourage are often critical. As a result, noise may be heard when PCBs are operating.

The characteristics of both a dry and a fractured connection can often be found in a cold solder connection. If you cannot recognize the solder junction design, seek the advice of a seasoned assembly service supplier. Long term, you’ll save both time and money.

Importance of Solder Joints in PCB

Semiconductor devices are joined to the circuit board at specific joining points called solder joints. It significantly contributes to raising PCB efficiency to a different level.

Solder joints’ form is fundamental. The contour of a flawless solder joint is hollow. To be able to access the tip of the PCB part, the molten solder must be smooth and slightly glossy.

The poor solder junction form prevents the PCB components from being connected perfectly. Additionally, it negatively impacts electrical characteristics. It causes PCB materials to frequently experience problems. Eventually, you’ll have to bear with expensive repairs.

A trained worker with knowledge of various PCB welding techniques is someone you need to supervise. To administer the solder wire and iron with precision and delicacy takes a lot of practice. Don’t disregard this problem as a result when producing circuit boards.

Primary Causes of Cold Solder Joints in PCB

The root cause of PCB cold solder junctions has already been addressed. However, a circuit board may experience cold joints for various reasons that aren’t always related to this problem.

In this, we’ve provided you with a list of the typical leading causes of cold solder joints:

  • Tin and lead poisoning in solder.
  • Improper arrangement of components.
  • Measurement Fluctuation.
  • Inadequate moisture.
  • Extremely low temperatures.
  • Reflowing waste particles onto the solder junction.
  • In response to high temperatures, solder flux breaks down prematurely.
  • Preferential soldering framework.
  • An irregularity between the PCB and its elements.

One can avoid cold solder connections in various PCB configurations by taking care of this problem.

How to Identify and Examine Cold Solder Joints?

We can comprehend the discomfort during PCB assembly owing to chilly soldiers based on our practical expertise. An electrician will find it quite frustrating to solve this problem, mainly if you work with a high-volume PCB fabrication.

Since cold soldiers are problematic, it’s important to spot them early on. If you don’t, you might go through some unpleasant things. For instance, the circuit board could stop responding altogether. The PCB elements can occasionally produce wildly erroneous results, which necessitates a significant amount of time.

There is a good possibility that an electronic program will become flawed if PCB activity continues with the unresolved cold solder problem. In order to swiftly discover and fix cold solder connections, you must perform trustworthy testing.

Hence, we’d like to provide insight into the various inspections we perform in such cases.

How to Identify and Examine Cold Solder Joint

Identifying and Examining Cold Solder Joints

Visual Inspection

Cold solder interconnections can be visually inspected to see if they are working. This method of locating cold joints is the simplest and most effective. Due to various soldering issues, it allows you to be sure that there are no cold joints.

One will need a magnifying glass and light for this test’s visual components. The connection of solders among opposite edges can be checked with these substances—the area where the element and PCB board interface need to be lighter. If you see that illumination rapidly flows through the solder joint, this is a sign that the solder joints have not been adequately bonded.

Additionally, cold joints have stiffness to them. It shows that the solder compositions are not sufficiently annealed. This issue may lead to the solder coming loose from the circuit board. Further, when used in an electronic circuit, PCB gets warm.

A further visual inspection is required. Solder joints are leaking onto a linked joint from the original ones. Although unlikely to occur, this situation does occasionally happen when soldering PCBs. It results in short circuit problems, which frequently cause the circuit board to collapse.

Checking Through Multimeter

A multimeter can be used to inspect cold solder junctions. There are two efficient ways to use a tester for this purpose. They are as follows:

  • Testing the Continuity – To the extremities of cold joints, one must attach two multimeter leads. If there is no disconnection issue, a beeping sound will be heard. If the solder joint beeps irregularly or not at all, it suggests a discontinuance, and if there is no noise, it necessitates rehabilitation. The voltmeter must, however, be initially set to the continuous setting.
  • Testing the Resistance – Adjust the tester impedance to 1000 Ohm for this test. The multimeter’s two wires should then be connected. Attach the terminals to various solder joints once confident that the resistivity is zero. The voltmeter value will not be zero in the event of a damaged cold joint. That implies that there is a cold solder junction present.

How to Repair Cold Solder Joints?

Notwithstanding one’s best efforts, a cold solder joint may appear on any circuit board. After that, you must handle the circumstance and correctly resolve the problem. The question is, though, how? There isn’t a simple, one-sentence solution to this query. It relies on the kinds of cold joints on your PCB and its structural strength. The following techniques are the most effective for repairing cold solder joints:

Problem Solution

Distributed Cold Solder

–          Employ a PCB holder or soldering clamp. It secures and stabilizes the PCB.

Typical Cold Solder

–          Adequately warm up the soldering iron.

–          Use lead-free solder cable with a faster annealing temperature shift.

Excessive Solder

–          To get rid of extra solder, use a hot iron point, solder wisp, or solder stripper.
Starved Solder Joints –          Reheat the solder junction and add additional solder as needed.

How to Prevent the Occurrences of Cold Solder Joints?

One must ensure that the soldering is efficient and flawless to prevent cold solder connections during PCB construction. In order to boost the soldering procedure, it is crucial to use the most excellent strategies feasible. One can carry out the actions listed below:

How to Prevent the Occurrences of Cold Solder Joint

Preventing the Rise of Cold Solder Joints

Using Appropriate Equipment

In managing cold solder joints, this is the step that has the most significant importance. Poor soldering tools are typically to blame for imperfect joining. To put it more clearly, don’t sacrifice when using a soldering iron. It carries out the solder wire’s melting process.

Consequently, use a soldering iron that is simple to handle and helpful for a regulated heating source. It must be gathered from a trustworthy source. Any further actions you make won’t be fruitful if you don’t.

Temperature Control

The temperature is a crucial factor regardless of the form of PCB soldering. To ensure that the solder wire melts effectively, one must establish a reasonable heat state that is neither more nor less.

Using Sufficient Solder

Cold soldering frequently results from over-soldering or junctions with staves. Therefore, you must prepare enough solder for the operation. Apply as little solder solution as possible. It lessens the likelihood of a situation with cold solder.

Proper Environment

Technically speaking, soldering calls for high-caliber perfection. As a result, the environment is crucial in this case. When soldering, the circuit board must be placed in a secure vice. Additionally, remove any potential sources of disturbance from that area.

Clean Soldering Iron

It’s essential to sterilize the soldering iron regularly. Additionally, ensure that soldering supplies are kept in an area free of dust. Try to prevent humidity from getting on the wires and soldering iron.

Flawless Power Supply

If using a soldering iron or gun, ensure it has a constant power source.

Lead-Free Soldering

According to RoHS, producers nowadays attempt to assemble PCBs following sustainable electronics standards. The use of lead-free and halogen-free solder wire is another way to help this cause. It increases ecological productivity and significantly lessens problems.

Time Management

All through PCB soldering, impatience is not permitted. One must allow the soldering iron enough time to heat up and thoroughly dissolve the wire. It wouldn’t obtain the desired result otherwise.

User Experience

Handling cold solder junctions requires confidence in your skills and knowledge. The soldering iron rattles a lot when new technicians become anxious. Maintain composure and accurately adhere to the soldering process configuration instructions.

One can consider hiring a reputable supplier to provide this service. Keep in mind the technical personnel can manage this by ensuring that they are knowledgeable and competent.


Technological device connections are strengthened through PCB bonding. Since cold solder junctions are a common issue with PCB implementations, one should take the necessary precautions to lessen their incidence.

In China, PCBTok is a reputable PCB producer. The business has been offering reliable assembly and production services, including soldering, for over twelve (12) years. Anyone can get in touch with the company to obtain the most outstanding service at an affordable rate. Stay tuned to learn more about the various PCB manufacturing processes.

Please don’t hesitate to contact us with any inquiries or requests!

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