PCB Measling: Everything You Need To Know in 2023


Every PCB experience various concerns after production if it isn’t produced well and without protection on its surfaces. Some of the issues it can possibly encounter is the PCB Measling and Delamination; however, these problems don’t occur often.

Measling isn’t a typical concern in every circuit board; however, once they appear, they pose a substantial risk to the device’s performance. Thus, it is highly suggested to address them right away and in an appropriate method.

One of the common causes of this phenomenon is the inadequate application of the resin because of the presence of humidity and other contaminants that hinder the sophisticated attachment of the resin to the board. If left untreated, these Measles will lead the device to malfunction, reducing the device’s electrical and physical performance.

As a result, we at PCBTok have decided to help our potential customers prevent PCB Measling by discussing its definition, distinction against delamination, its causes, reasons for appearance, ways to prevent them, and assessing their presence. Therefore, we suggest reading the entire post until the end to grasp the PCB Measling concept fully.

Introduction to PCB Measling

Introduction to PCB Measling

What is PCB Measling?

As stated, the PCB Measling forms due to the poor implementation of resin directly through the board. As for their appearance, they are likely white spots. Further, they frequently rise following the manufacturing cycle, indicating that the board is defective.

Typically, the presence of tiny Measles doesn’t necessarily affect the performance of the device; however, if the PCB Measling is enormous, it can significantly affect the electrical and overall efficiency of the circuit board. In terms of PCB Measling cause, they are commonly due to the presence of moisture and harmful contaminants.

In order to address this problem, it is essential to have proper manufacturing techniques to lessen the formation of PCB Measles. Hence, it is necessary to approach a manufacturer with extensive industry experience to avoid this occurrence. Additionally, PCB Measling might develop due to significant pressure in addition to production-related factors.

What is PCB Measling?

Definition of PCB Measling

Difference Between Delamination and Measling

Although there are a lot of people that quickly get confused between Delamination and Measling; hence, we will provide a clear distinction between these two in this section.

  • Delamination – It typically occurs during the production process when there is too much heating or dampness. Basically, if there is a substantial detachment of the layers of the PCB foundation materials, it will culminate in blister-like spaces or bubbles, thus creating PCB Delamination.
  • Measling – Typically, this occurrence happens due to stress and the production phase. In essence, it’s the existence of white flecks inside the PCB mesh. Some modest Measling can be permitted if they are not overly widespread or lack Measling that straddles conductors and welding junctions since they don’t signify the obliteration of the board’s constituents.

Testing PCB Delamination

Various Causes of Measling and Delamination

Misusing resin is one of the central issues of Measling. Nevertheless, its formation can be limited through the help of a proper production approach. Another cause would be the mechanical stress experienced by the circuit board. Additionally, PCB Measling might appear at any time; but in some circumstances, a minuscule fraction of it is remarkably harmless.

As for Delamination, usually, it can only happen when something is being produced. If humidity intensity increases, the lamination could lift up and cause holes in the layers. Besides that, as dampness is typically caused by heat sources that have the capacity to generate a gas, inorganic materials may develop delamination when subjected to extreme heat pressure from welding. A poorly managed lamination technique, thermal stress, and employing the incorrect temperature for glass transition are additional causes in conjunction with that one.

Why Does PCB Measling Appear?

Typically, the materials used to build PCBs are made from FR4, considered hygroscopic. Hence, they can easily absorb moisture from the environment. Along with that, it is recommended that it should be stored in a temperature-controlled setting because once the board gets subjected to soldering iron, reflow oven, and other approaches that utilize heat, its moisture will then evaporate, resulting in the formation of Measles. In the end, it can form in fiberglass mesh, but it can also develop in the prepreg sealant inter-layer.

Apart from the material utilized, PCB Measling could occur due to the manufacturer’s negligence. In fact, lower-quality PCB manufacturers could not always have the constraints required to join the PCB’s layers effectively. The consequence is PCB Measling, which are white patches.

How to Prevent PCB Measling?

One of the most straightforward approaches to prevent the occurrence of PCB Measling is going to the well-experienced and trusted manufacturer; this will ensure that all of the materials involved in the production of the circuit board are top-tier. Further, by selecting such a manufacturer, we can guarantee that they will only perform quality techniques that abide by the standard guidelines. However, it doesn’t end here; there are other ways to ward off PCB Measles.

Some of the ways are mentioned below:

  • By using the highly monitored production method.
  • By establishing appropriate resin temperature and monitoring systems.
  • By ensuring that the PCBs are stored in a dry environment and paying attention to the Surface Finishes.
  • Prior to actually beginning any thermal treatment, keep the board at a constant temperature.

PCB Measling: Test Procedure

There are various ways to evaluate Measling in a PCB during a testing phase. However, a single unique method is followed by practically all producers. Its process is pretty straightforward; essentially, this approach introduces the laminate to humidity before being placed within the molten solder paste. Typically, the laminate is immersed in solder paste at a temperature of roughly 500°F or 260°C.

In essence, we carry out this evaluation since it is utilized to determine the board’s functionality. Additionally, the board shows up for the subsequent stage after successfully executing the phase. Afterward, the laminates undergo solder treatment and etching in the subsequent steps. This particular method generates a PCB of excellent quality that is Measling and white spot-free.

Nevertheless, one shouldn’t use the circuit’s subsequent etching and soldering steps if it fails the examination. Instead, the board will seem cluttered with white patches and Measling, which will be a colossal waste of time and energy.

PCB Measling: Test Procedure

Evaluating PCB Measling


To wrap things up, it was proven that PCB Measling is a highly destructive concern that a PCB could experience; however, if followed the proper guidelines as they should be performed, we guarantee that this phenomenon wouldn’t be any problem. Hence, it is essential to research the manufacturer’s capability before utilizing their service.

As one of the leading manufacturers in China, PCBTok has been recognized globally because of its exceptional service performance and remarkable quality of produced products. We have built our reputation for over a decade and will continue to thrive on this legacy. Hence, if you’re afraid of the PCB Measling formation, then look no further; PCBTok is an expert and experienced in this field, and we haven’t encountered any customers that returned to us after receiving our finished products with the presence of Measles.

At PCBTok, we only want the finest for our customers. So, what are you waiting for? Send us your requirements regardless of their complexity, and we can provide them for you! By sending us a message today, you can get a chance to avail our daily ongoing offers! Contact us right away!

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