Causes, Tests, and Tips to Avoid Insufficient Solder in Your PCB


Insufficient solder can be a frustrating problem for PCB designers, especially when it comes to troubleshooting. There are many different factors that can contribute to this issue. This is making it difficult to pinpoint the exact cause of insufficient solder on your board.

In this article, we’ll go over some of the most common causes of insufficient solder, as well as some tips that you can use to avoid it in your PCB design work.

Insufficient Solder

Insufficient Solder

What is Insufficient Solder?

This is a problem that can occur when you’re soldering a component to a PCB. It happens when you have too much solder on the pad of the component. This prevents it from making contact with the PCB.

Insufficient solder is a problem that can happen when you’re soldering a joint. Insufficient solder happens when the molten metal pools or pools around the wire but does not completely cover it. This can cause problems with electrical conductivity and mechanical strength. The joint may be weak and break easily. It might not be able to carry enough current to power your project.

Insufficient Solder and Excess Solder Difference

Insufficient solder happens when there is not enough solder to fill the gap between the components being joined together by the heat of the soldering process. This can be caused by not having enough flux in the joint, not enough heat, or not enough time for the solder to flow into all of the gaps between components. If this happens, there will be a gap between components that weren’t intended.

Excess solder happens when there is too much solder for a given joint size and configuration. This can occur when too much flux has been applied to a joint. Also when a very small area is being soldered but too much heat has been applied to it. The excess solder will flow out beyond where it should go.  Creating a bump on top of the joint instead of an even surface.

Causes of Insufficient Solder

There are many causes of insufficient solder. Here are some of the most common ones:

Non-Coplanar Leads

Non-Coplanar Leads

Non-Coplanar Leads

When you’re soldering, your goal is to make sure that all of the leads are in contact with the pad and that no air bubbles are forming in between them. This can happen when the component’s leads aren’t perfectly coplanar, or they are not at the same height.

Excessive Warpage

Excessive Warpage

Excessive Warpage

Insufficient solder can also be caused by these when soldering. Once the components have been soldered, the solder should be allowed to cool for at least 5 seconds. If the parts have warped before this period has elapsed. It will be difficult for the solder to form an adequate bond and this could result in insufficient solder.

Poor Wetting

Poor Wetting

Poor Wetting

Wetting is the process by which a fluid like solder spreads across a surface like a PCB. It’s important that the solder can spread easily and evenly over the entire surface because otherwise, it will form only along certain areas. The resulting solder joint will be weak, which in turn can cause circuit failure.

Improper Printing Parameters

Insufficient solder is caused by improper printing parameters. The most common cause of insufficient solder is when the extruder temperature is set too low, causing the plastic to flow too slowly and not fill the entirety of the soldering tip.

Another thing to look out for is an incorrect nozzle size. If your nozzle is too large, it will cause a lot of plastic to flow out at once instead of more consistently over time, which can lead to an inconsistent amount of solder in each print.

Blocked Stencil Aperture

Blocked Stencil Aperture

Blocked Stencil Aperture

Stencils are used to apply solder paste to PCBs. The paste is spread evenly across the pad areas before being melted by a hot plate or oven. When there are no holes in the stencil, it prevents solder from transferring properly onto the pads, which can lead to insufficient solder flow.

The problem with this issue is that it can be difficult to detect at first glance. When using an infrared camera, you may see no difference between having holes in your stencil or not having them.

Misaligned Solder Print

The cause of insufficient solder can be traced back to the solder print alignment, which is the distance between pads and traces on the board. If the board has been printed with a misaligned print, then there will be too much or too little space between the pads and traces, resulting in insufficient solder.

Improper Stencil Thickness

When a stencil is too thin, there will not be enough solder to fill all of the holes in the board. The result will be missing solder connections and possible short circuits.

When a stencil is too thick, it does not allow for enough heat to flow through it and melt the solder paste adequately.

Excessive Pad Size

Excessive Pad Size

Excessive Pad Size

When you’re designing your PCB, it’s important to make sure that all of your pads are big enough to accommodate the amount of solder needed to make a good connection between layers. If you have larger pads than that, then you’ll end up with insufficient solder on your board and have trouble making good connections.

If you notice that your printed circuit boards are having trouble making good connections, start by looking for any large pads on your board and see if there’s anything about them that could be changed.

Preheat Too Aggressive

The purpose of the preheat is to remove any moisture from the board, and this is done by heating it up quickly and then cooling it down just as quickly. If the preheat is too aggressive, it can cause the solder to flow too fast when you come to solder it.

The easiest way to avoid insufficient solder is to use a lower temperature for your preheat.

Peak Reflow Temperature Not Attained

The reflow process is used to solder components and pads together, which makes the final product more durable and reliable. However, if the temperature is not high enough, there will be insufficient solder on each pad. This can lead to poor connections between components or pads, causing them to come loose or fail altogether.

Malfunctioning Oven

Malfunctioning Oven

Malfunctioning Oven

The soldering oven is used to heat the circuit board to allow the solder to melt and flow over the pads on the circuit board. If there is not enough heat, then the solder will not flow properly, resulting in insufficient solder.

Tests on How to Know Insufficient Solder in your PCB

If you’re having trouble with your PCB, here are some tests to do to determine if the problem is insufficient solder.

Thermal Shock

The thermal shock test is a way to determine whether your PCB has sufficient solder. It works by increasing the temperature of your circuit board, then cooling it again quickly. If there’s not enough solder in your circuit board, it will crack or warp when subjected to these sudden changes in temperature.

Random Vibration

This test is designed to determine if there is insufficient solder in the joints of your PCB. The test will be conducted by placing the board into a vibration machine that will shake it for a given amount of time. If there is insufficient solder, the board will not hold together during this test.

Combined Environment

There are many ways to test for insufficient solder in your PCBs, but one of the best ways is by running a combined environment test. This test uses both thermal and mechanical stresses on a PCB under different temperatures and humidity levels for a specified period of time.

The results will show if there are any cracks or holes in your board that could cause problems later on when you’re using it. If there isn’t enough solder on your board, you’ll see some kind of damage after running this test. For example: if you have cracks or holes in an area where there should be solder present but isn’t, then that means there’s not enough solder there to hold things together properly during operation.

Bend Test

The bend test is a simple way to determine if there is insufficient solder in your PCB. This test can be performed by hand or machine. If you are performing it by hand, you will need a magnifying glass and a strong light source. If you are performing it with a machine, there are many devices on the market that can perform this test for you.

To perform this test, place the PCB under scrutiny on a flat surface and look for any cracks or other signs of cracking or separation from the board. If there are any cracks, then you should consider re-soldering your board before using it again.

Tips to Avoid Insufficient Solder

Insufficient solder is a common issue when soldering. Here are some tips to avoid insufficient solder:

Print Enough Solder Paste

One of the most important things you can do to avoid insufficient solder paste is to print enough paste. You want to make sure that you’re printing enough solder paste, so that it covers the entire board. If you don’t print enough, then there will be spots on your board where there isn’t any solder paste at all. Those spots won’t be covered by solder when you apply heat.

In order to avoid this problem, make sure that you’re printing enough solder paste for each layer of your board. This will ensure that all of your holes get filled in with solder. No parts of your PCB are left uncovered by solder.

Cover the Vias with Soldermask

When you’re soldering, it’s easy to accidentally let some of your solder flow onto the vias that connect your circuit board components. This can be a problem. There’s no way for the solder to make contact with the pad underneath it after it’s cooled down.

To avoid insufficient solder, you should cover the vias with soldermask. This will prevent the solder from bridging and creating a weak point in your PCB.

Accurate Alignment of Printing Solder Paste

Solder paste is an essential part of the final product. It is used to fill the gaps between components and components and provides a strong electrical connection between them. If you don’t have enough solder paste, your connections may be weak or short-circuited, which can cause problems in the long run.

You can avoid insufficient solder paste by using an accurate alignment tool to place the solder paste on your PCBs. This will ensure that all of your components are properly connected and that there aren’t any voids between them.

Accurate Alignment of Components

If you want to avoid insufficient solder, make sure that your components are properly aligned. It’s not enough to just throw them together and hope for the best—you need to make sure they’re aligned correctly so that they can conduct electricity efficiently.

Proper Preheating to Avoid Warpage

The problem is that many people think they can just put their connector in place and start soldering right away, but that’s not how it works. In order to avoid insufficient solder and poor connections, you need to preheat your connectors and connectors. You have to clean them before applying any solder. By doing this, you can make sure that there isn’t any oxidation or other contaminants on either one. That could affect your connection quality or durability over time.

Proper Solder in PCB

Proper Solder in PCB


The tips listed above will help you to use the most appropriate materials and processes to avoid insufficient solder in your PCB and having to order a new batch of boards. They’ll also help you know where to look if you do have insufficient solder so that you can solve the problem as soon as possible. The sooner you find the issues, the better. Otherwise, it could lead to problems later on down the line such as mechanical breakage or even electrical connectivity issues.

Update cookies preferences
Scroll to Top