What is a cold soldering connection and how do you prevent it? PCB & MCPCB – Best Technology

When a cold soldering connection appears on the PCB, it may not fail immediately. But over time, it can cause real problems – intermittent signals, unstable connections, or even total circuit failures. These defects are often hidden, and if they are not caught early, they can waste time and money in re -work.

On this blog, you will learn:

• Cold Solder Connection Visible
• What causes it
• How to avoid and fix it
• Why Trusted PCB Assembly Partners Like Best Technology Matters

What is a cold soldder joints?â € ‹

Solder Cold Solder Connection or Cold Connection, is a damaged connection between lead components or terminals and PCB pads during the PCB assembly process. Unlike the rules of solder that is formed correctly, which provides strong and reliable electricity and mechanical connections, cold solder joints fail to fully bind the two elements together.

When solder is done correctly, solder melts completely and wet the two tin components and PCB bearings, creating a smooth, shiny, and concave surface. However, in the case of cold solder joints, solder does not reach the optimal melting point or does not flow properly. This produces a rough, boring, and often uneven surface. The joints may look like they are attached, but in reality, the relationship is weak and vulnerable to failure. This may do electricity for a while or not at all, which leads to erratic behavior on electronic devices, from occasionally disruption to completing damage.

Causes of cold soldering jointsâ € ‹

Some factors can contribute to the formation of cold solder connections. Understanding this cause is the first step in preventing it

• Inadequate soldering temperatureâ € ‹

One of the main causes is insufficient soldering temperature. Each type of solder has a specific melting range, and if the solder or oven reflow does not reach and maintains the appropriate temperature, the solder will not melt completely. For example, if the temperature is too low, solder is only partially liquid, leaving solid particles that prevent proper bonds.

• WRONG Solder timeâ € ‹

If the soldering iron is applied too short, solder will not have enough time to melt and flow properly. On the other hand, too hot joints by leaving the Solder iron for too long can also cause problems. It can damage the tin components, PCB bearings, or even change the nature of the solder itself, potentially leading to the cold solder connection.

• Poor surface preparationâ € ‹

Cleanliness and surface conditions to be soldered are very important. If the component leads or pcb bearings is dirty, oxidized, or contaminated with oil, residues, or other substances, solder will not stick correctly. Oxidation, in particular, forms a thin layer on a metal surface that acts as a soldering barrier.

• Use of inappropriate fluxâ € ‹

Flux is a key component in the solder process. It helps clean the surface, eliminate oxidation, and promote solder flow. However, using the wrong type of flux, too little flux, or applying it incorrectly can cause cold solder connections. Some fluxes may not be compatible with certain solders or components, while inadequate flux will not provide enough cleaning and wetting action.

• Movement of components during solderâ € ‹

When the component moves while solder is still liquid, it can interfere with the right joint formation. This can occur due to vibrations during the polishing process, inappropriate PCB handling, or inadequate security of components. Even small movements can break the developing bonds, resulting in cold solder connections or weak connections.

Cold soldering joint imageâ € ‹

Visual aids can be very helpful in identifying cold solder connections. Here are common visual signs:

• Dull and rough appearance: good joint shiny and smooth. The cold looks frozen or matte.
• Crack or gap: visible separation or cavity between components and PAD.
• Shape like a ball: If the solder beads up instead of flowing smoothly, most likely not binding.
• Lifting lead: The component that seems a little from the bearing might indicate a cold connection below.

Below are some examples of cooler solder images Example: â € ‹

How to identify good solder jointsâ € ‹‹ ‹

Identifying a good solder connection is as important as recognizing the cold one. High -quality soldering joints have several different characteristics: â € ‹

1. Appearanceâ € ‹

A good soldering connection must have a smooth, shiny, and concave surface. The solder must flow evenly around the tin of the components and to the PCB pad, form a natural fillet.

2. Elimination

The right removal is the main indicator of a good solder connection. Solder must spread and attach evenly to lead components and PCB pads, cover the surface completely. When wetting is correct, there will be no gaps, cavities, or naked spots where the metal surface is exposed.

3. Strengthâ € ‹

A stronger connection must be strong enough to hold the components in its place. Gently pulling the component (with the right treatment not to damage it) must express a solid connection.

How to avoid cold soldering joints’ ‹‹?

Prevention is better than improvement. This is how to keep the cold soldering joints in the first place:

1. Use the right temperature

Always adjust your solder iron between 350 ° C to 400 ° C for standard tin -based solder. Higher temperatures may be needed for lead -free types.

2. Pacific bearings and Leads

Use isopropyl alcohol to clean the surface before soldering. Dirt and oxidation are invisible enemies.

3. Don’t pass the flux

Flux eliminates oxidation and increases solder flow. Many solder cables enter it, but extra flux helps in difficult places.

4. Stay with a great hand

Hold the components and iron stable until the solder cools. Use clamps or tools if needed.

5. Choose a quality tool

Ironing iron with an unstable end causes inconsistent heat. Invest at a reliable solder station with temperature control.

6. Working in a clean and safe area

Humidity, static, and poor lighting all increase the chances of making mistakes.

How do I fix a cold soldering connection ‘‹‹ ‹‹ ‹‹ ‹‹

Apart from our best efforts, cold solder joints may still occur. Fortunately, there is a way to fix it: â € ‹

1. Solderâ € ‹

The first step in improving cold solder connections is often defeated. Use reduced pumps or axes to remove existing solder from the connection. Heat the joints with solder iron to re -make the solder, and then use a desperation lane to suck or absorb liquid solder. Make sure to delete all old solders completely to start fresh.â €-

2. Cleaning â € ‹

After decreasing, clean the surface again to eliminate the residue of flux, oxidation, or other contaminants that may accumulate. This step is very important to ensure the right improvement. Use the appropriate cleaning solution and brush or clean cloth to wipe the clean surface.â € ‹

3. Resolderingâ € ‹

After the surface is clean, it’s time to resell the connection. Apply a little fresh flux to the surface that is cleaned, and then heat the connection with the solder iron. When the flux begins to bubble and activate, feed a small amount of solder into the connection.

4. Inspection and Testing € ‹

After being resold, check the joints visually to make sure it looks good and meets the criteria for the right solder connection. Then, use testing equipment to verify electricity connections. Check continuity and make sure the connection is to conduct electricity properly. If there are problems found, repeat the process of temples, cleaning, and re -sales until the connection is repaired.â € ‹

Trust the Best PCB Assembly Service Provider – Technologyâ € ‹

Avoiding cold solder joints is not only about skills € also about choosing the right PCB assembly partner. The best technology, we follow the strict quality process to ensure that every joint is clean, strong, and reliable. This is how we guarantee excellence:

• Automatic solder equipment: oven reflow, selective solder, and wave solder eliminate manual errors.
• X-Ray and AOI Inspection: We detect hidden cold connections and ensure solid connections throughout.
• Skilled Technician: Our team is trained for international IPC standards, ensuring accuracy with each combined solder.
• Fast prototype and mass production: whether you improve or perfect, we support your project at each stage.

Need a flawless assembly for your next project? Contact the best technology today for offers or consultations. Let’s build something that can be relied upon “together.

FAQ

1. What is a simply cold soldering joint?

Solder points that are weak or not connected badly that are not properly heated and can fail over time.

2. Are cold solder joints dangerous?

Yes, they can cause the circuit to fail, especially in a critical safety system such as medical or automotive electronics.

3. Can the cold solder connection be repaired easily?

Yes, with the right tool, you can reheat and fix it quickly.

4. What is the shape of the cold soldering joints?

Often looks dull, cracked, rough, or uneven € ”unlike joint who is shiny and smooth.

5. Can the PCB test pass a cold soldering connection?

Yes, especially if the mistake is cut off. That is why visual and X-ray inspection is important.

Tag: Cold Solder Connection, Causes of Cold Solder Connection, “Cold Solder Joint”