What Is PCB Measling?
Have you ever noticed small white patches on the core laminate layer of a printed circuit board? Yes, you have got it right! These white spots are called PCB measling. It mainly occurs when the resin does not get applied correctly during the lamination cycle. Now, you may wonder why the resin does not get applied correctly?
Well, the answer is simple! Sometimes the existence of extra precipitation or some other components hampers the natural state of the resin. Then, the unwanted lighter-colored smudges arrive, and the entire printed circuit board becomes poor in quality. PCB measling generally gets seen in multilayer printed circuit boards with more than four layers. The spots are mainly found at the edge of the prepreg adhesive as well as within the fiberglass weave, entirely unattached to the prepreg.
A printed circuit board containing a considerable number of measling is tolerable. But, in case a PCB contains lots of measling, it should not be accepted. This is because the existence of excessive measling on a printed circuit board impacts the across-the-board bodily and electrical execution of the circuit boards and stimulates PCB malfunctioning.
So, have a look at how you can avoid PCB measling and learn the measling test procedure as well. Read till the end of this guide and grab all the detailed information about PCB measling.
How to prevent PCB Measling?
Printed circuit board measling is a common occurrence for all PCBs. PCB measling can naturally be staved off by going for the precise PCB manufacturing method, keeping the components where the climate is perfect, and using resin controls. Another great way of reducing the chance of PCB measling is to preserve all PCBs in an arid and airtight area. In this way, you can guarantee the oxide layer on the inner sheets of the printed circuit board is alright.
But, there are other techniques as well. The best way to dissuade PCB measling is to adopt a quality printed circuit board fabricator. You can also put some extra effort and conserve the boards inside a condensation resistance bag and in a dry place, or ESD.
When it comes to the PCB assembling or PCBA process, you should not touch or open the bare boards. If you remove the care boards into the open air and leave them without even using them, the rest will get damaged for sure. However, if you already have some boards that are already exhibited measling, make sure to bake the boards in advance before using them. Additionally, do not forget to stuff and run the affected boards to check their compatibility.
According to the IPC standard, you can bake the boards at a temperature of one hundred to one hundred and five degrees Celsius for almost four to six hours and more. Once the boards get high heat like that, they become safer for use. But, there is a problem with baking. Once you bake a certain board, it sometimes inaugurates solderability into the board. So, it is recommended to go for baking only when it is necessary. Otherwise, following the processes mentioned above can help you.
In a nutshell, PCB measling is nothing out-of-the-box concept. It just needs a little attention and some techniques to get avoided. First, make sure to appoint a high-quality printed circuit board manufacturing partner if you want to avoid all hassles related to PCB measling. Then, have a look at some widespread ways to prevent PCB measling.
- Opt for a well-managed PCB manufacturing procedure
- Make sure to run the PCB assembly process under a proper temperature
- Always try to use resin control methods
- Ensure that the surface finishes of the circuit board are good in quality
- Always rest the printed circuit boards in a dry place
- You can use moisture resistance bags to store the PCBs so that they do not come to direct contact with air
- Always make sure to maintain the temperature of the board before going for the thermal processing
- Always contact a professional PCB manufacturer for getting advice related to PCB measling and how to avoid it
Measling Test Procedure:
There are many when it comes to the test procedure to assess measling in a printed circuit board. But, most printed circuit board manufacturers use one particular special technique. In this method, the laminate gets exposed to moisture before plopping it inside the hot solder paste. Generally, the solder paste temperature in which the laminate gets submerged revolves around five hundred degrees Fahrenheit.
This special technique generally gets used to test the compatibility of the board. Once the board successfully passes through the stage, it appears for the next stage. In the next stage, the laminates go through etching and solder processing. In this way, a measling and white spot-free good quality printed circuit board gets prepared.
But, in case your board does not pass the test, you should not apply the next etching and soldering processes to it. Otherwise, it will be a complete waste of time and effort, and your board will appear full of white spots and measling.
Conclusion
These were all you need to know about PCB measling, the processes of preventing it, and the measling test method. Hopefully, you have now understood everything related to PCB measling. But, still, if you are facing any issue related to printed circuit board measling and do not know how to avoid it, we are always here to help you out. We provide our customers with all necessary recommendations and processing needs so that they can effortlessly eliminate unwanted measling from their printed circuit boards.
Remember, however normal PCB measling is, it should be taken good care of if you want a satisfying printed circuit board finish. So, no matter whether you are facing this problem related to PCB measling for a single or large-scale production, your problem will undoubtedly get solved with our highly professional engineers. So, contact us at your early convenience.
