Cold Solder Joint – The Definitive Guide To Soldering
As already noted, a cold solder joint is a solder joint problem that often occurs during soldering when the solder fails to melt entirely and flow to form an ideal solder joint. Cold solder joints often appear dull and make convex mounting on the pins and the board flex areas. Sometimes, they also take rough shapes, as shown in image 2. A cold solder joint or an improperly formed joint can be the trigger for reliability problems of an electronic assembly. Cold solder joints increase the electrical resistance of the solder joints, and hence reduce the reliability of the solder joints. There are a number of factors that can cause cold solder joints.
Home » Hardware » What is a cold solder joint? Years ago, my monitor broke. Back how to write a how to write book we had repair shops for such things. I called one and described the symptoms I was having. But what is a cold solder joint? There are several types of underperforming solder joints, all of which tend to give the same symptoms.
The cause can be different, but the overall effect is the same. These are cold, cracked, and dry solder joints. All of them result in intermittent or lack of electrical conductivity, which means unreliable operation.
A cracked solder joint is just what it sounds like. This allows the pin to move around in its hole in the circuit board. Depending on where it moves, the electrical connection can stop or start.
Heavy components on boards mounted vertically are more prone to cracked solder joints, due to gravity. Vibration exacerbates the problem. Solder is metal heated to liquid, and the goal is to flow it into the joint and wet the entire connection before the solder freezes back into solid form. These look dull, so they are easy to identify. A cold solder joint just is one of the two. If you want to be pedantic, a what can you do for ear mites in dogs solder joint can be cracked, dry, or both.
And technically, not all cracked or dry solder joints are necessarily completely cold. A good solder joint is shiny and cone-shaped, ideally slightly concave, like a volcano, and smooth, not lumpy. A cracked solder joint has a crack in it. The solder can be either shiny or dull. The crack is the bigger problem, usually. The quick fix for a cold solder joint is reflowing. Add a bit of flux to the cold solder joint, heat up your soldering iron, and touch the soldering iron to the joint to remelt the solder.
Hold it there for a second or two, then pull the soldering iron away. If all goes well, the result is a smooth, concave joint. If you know what kind of solder it is, you can try again, adding a bit of fresh solder. It should mix well with the existing solder. If it was made afteruse a lead-free solder. Add flux, heat up the joint, and touch just a bit of solder to the joint. The safer thing to do is remove the solder and completely what makes you you quotes the joint.
Add flux, then use a desoldering wick, desoldering pump, or desoldering gun to remove the old solder. A trace of solder will remain on the surfaces, but the pin will move freely in its hole. Add fresh flux, then solder with whatever solder you like.
Apply heat to the joint, not the solder. The heat from the joint pulls the solder in. Let it cool, and examine the joint afterward. It should be smooth, shiny, and concave. If it is, clean it with isopropyl alcohol, contact cleaner, or mineral spirits to remove any remaining flux. This site uses Akismet to reduce spam. Learn how your comment data is processed. Types of cold solder joints The solder joint near the center looks like a cold solder joint to me.
The one on the upper left seems suspect too, it looks a bit lumpy. The ones on the right look pretty good. Cracked solder joint A cracked solder joint is just what it sounds like. Cold solder joint A cold solder joint just is one of the two. What does a cold solder joint look like? A dry solder joint is dull, and likely to be the wrong shape. How to fix a cold solder joint The quick fix for a cold solder joint is reflowing.
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What does a cold solder joint look like?
Jan 14, · A cold solder joint doesn’t refer to temperature, but rather, lack of electrical conductivity. A cold solder joint is a solder connection that isn’t conducting electricity the way it should. Types of cold solder joints The solder joint near the center looks like a cold solder joint to me. Cold solder joint is an electrical soldering joint where the joining metal or the solder has not been heated enough to form a proper joint. It often results in cracks in soldered joint over the period. The sole reason for this to happen is insufficient heating of joints while soldering. It can be solved by simply re-heating the joint. Dry or cold solder joint means that there are a small quantity of tin column in the welding spot, which causes bad contactin the circuit.. Well, in order to solve such a problem, we should pay more attention to at least these aspects, such as the quality of solder paste, flux quantity and quality, the temperature of soldering iron, soldering time, components itself quality (No pin oxidation.
Have you ever encountered cold solder joint in the past? How did you solve the issue? Did you get online help? Most engineers have to face the problem of producing unreliable electronics due to cold solder joints, either during the Industrial PCB assembly or when prototyping with newer trends like say when using the flexible PCBs.
Because of these concerns, we ventured to research more on this particular topic and try to answer questions that could worry PCB designers. This edition is a collection of information on cold solder joints that could help you to develop better PCBs. Have you ever encountered a cold solder joint in the past? Most engineers have to face producing unreliable electronics due to cold solder joints, either during the Industrial PCB assembly or when prototyping with newer trends like, say, when using the flexible PCBs.
We ventured to research more on this particular topic and try to answer questions that could worry PCB designers because of these concerns. This edition is a collection of information on cold solder joints that could help you develop better PCBs.
Soldering is the process of forming electrical and mechanical connections on a Printed Circuit Board PCB by connecting electronic components to the board using an alloy of molten Lead and Tin. It is a fundamental skill in electrical engineering as it stands as a central part of developing and troubleshooting circuits. Soldering is often done using a solder station or a soldering iron and a solder wire the alloy of tin and lead.
A subtle tip of metal or a relevant metallic material is attached to a controlled heating element connected to a power source during soldering. With time, the solder iron tip gets heated to degrees that can melt the solder wire to become molten and aids in making a solder joint. Soldering is the skill that is responsible for mounting electrical components on PCBs. A solder joint is merely a specific soldered point of interconnecting an electronic component onto the PCB.
A cross-section of an ideal solder joint should have a smooth and glossy concave-shaped molten solder that climbs up the pin of the element that is to be soldered as shown in image one below:. As you can guess from the simple explanation or from experience , good soldering is an acquired skill that requires much practice.
For most of us, this skill is perfected with time over repeated projects and experiments. Moreover, even then, you are never entirely free from error per se; you only become a little bit more improved than you were before the practice. Meaning, every time you solder a component, you get yourself a chance to do it better than before or learn a better way to do it from a mistake you will make. There are various mistakes you are likely to make during this process of soldering. Some of the common soldering mistakes you might make during making solder joints include:.
A disturbed joint: formed when a solder joint is disturbed before the molten solder solidifies. A cold joint: one where the solder fails to melt entirely after soldering. An overheated joint: this problem occurs when the soldering wire fails to melt despite heating. This act results in overheating the flux on the board, which complicates the soldering experience. Insufficient wetting: This problem happens on either the pin or the board.
It is an indication of not heating the solder unevenly on the board and the pin. Inadequate wetting of the pin shows that you burned the pin more than the board. Inadequate wetting on the board, on the other hand, could indicate the application of too little wetting material.
As already noted, a cold solder joint is a solder joint problem that often occurs during soldering when the solder fails to melt entirely and flow to form an ideal solder joint. Cold solder joints often appear dull and make convex mounting on the pins and the board flex areas. Sometimes, they also take rough shapes, as shown in image 2.
This cold solder joint often arises when one fails to heat the solder wire properly before soldering. In some cases, it can also emerge when one disturbs either the board or the soldered pin before the molten solder solidifies. In the subsequent chapters, we will examine more details on detecting and repair cold solder joints. We will also suggest practices that can help you to minimize the occurrence of cold solder joints. Nobody appreciates the importance of testing for cold solder joints like one who works on large electrical projects.
Look, here is an annoying stage I do encounter when working alone on electronic projects. I wonder if such a story relates to your daily work experiences too. It goes something like this:. I am working on an electrical module for a larger industrial project. My role is to develop one of the fundamental hardware components for the more massive project.
I already have the software, and electrical component tested on a regular breadboard and uploaded onto a microcontroller, ready for soldering. About 30 minutes later, I get done with the entire project. Everything looks fine from my end or so I should say. So, I power it up and start monitoring it. Moreover, guess what? So, I replace the resistor with a different one. I check for the multimeter and begin evaluating each component.
I notice a single cold solder joint and fix it. The device works, but then it gives unexpected readings. I get worked up and set for a new circuit examination using a lens.
I later discover a different cold solder joint after about another hour or so and fix it. This time I manage to bring it under control after a long and tedious experience that might sometimes bring you behind schedule. Do you see it? Without evaluating cold solder joints, you will run a risk of developing a defective electronic. Checking visually for cold solder joints and fixing them should be your primary step when developing circuits. We had already described how an ideal solder joint could look like in chapter one.
Primarily, a cold solder joint could look dull, whitish, and convex, or deformed. Moreover, maybe you are wondering why I have introduced it. Sometimes it goes beyond what we see with our eyes. You might need to get a magnifying lens and check through the solder joints to note the convex shape and that the solder filled the gaps. Often, such joints appear to be rough on a close examination. Also, when you suspect a joint, you should try to tilt the component mounted on the joint to see if it detaches.
Should such a thing happen, try and fix it with the methods we will discuss in the ensuing chapter. It is also critical to ensure that the solder does not spill over to other joints as this could create short-circuiting within the circuit. When testing for cold solder joint using a multimeter, there are two measures you can use to establish a cold solder joint.
These are:. Here you will begin by switching the multimeter to measure resistance. Depending on the multimeter type, you will either rotate the indicator or press a few control dials to switch. Use a resistance of about 1K ohms for this experiment.
Next, you connect one terminal of the multimeter directly to the other terminal of the meter. Here it would help if you read a resistance of zero ohms.
This step is to verify that your multimeter functions correctly. For non-resistor electrical components, you should observe a zero. Any reading above zero could be an indicator of a cold joint.
Using the same multime ter we used in test 2. Connect the two ends of the multimeter and notice that the multimeter beeps to indicate continuity. Image 3: Photo with an indication of continuity label. Once you are satisfied, repeat the process by connecting the two ends of the multimeter to the two ends of the circuit.
If the multimeter beeps, then all could be fine. Anything else is an indication of a discontinuity that could be a result of a cold solder joint. No specific device can test for cold solder joints. All the tests explored above are based on trial and error. This fact is the reason why you should not fail to make mistakes when doing this.
Thus, you should do all this courageously and be willing to rectify anything you encounter with the methods in chapter 3. Over time, with more solved mistakes that you make , you begin to become a little better than before.
Just like a beginner makes mistakes, professionals make mistakes too. The only difference is the type of errors and the amount of time they take to solve the errors. So, why should you be afraid? We will begin with:. These are the main types of cold solder joint problems to engineers.
These solder joints occur when either the component or the circuit board is moved before the molten solder mounts correctly. They are characterized by a concavely shaped look and tilted pin within the solder.
On a close observance, they are also likely to appear rough and a bit frosty. Primarily, they cannot be comfortably classified as cold solder joints as this type of joint sometimes may be made from well-molten solder.