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Black PCB - An In-Depth Guide About It

You might have seen black PCB. The real color of the PCBs is the solder mask, not PCB itself.

 

In most cases, the Printed Circuit Boards are green in color. There are a few cases where different colors are used, and for this particular case, we will focus on the black PCB. 


One of the main reasons why the solder mask is kept black is because the reflection of the light is not desired in such circuits. 

Continue reading this guide to know more.

1、Black PCB

1.1 Definition

Printed Circuit Boards come in different colors. The most commonly used color is green which appears in most of the PCB’s that are present in the market. The other colors that may suffice include red, blue and black PCB among many others.

 

In this particular article, we will focus on the black PCB. The black PCB has its solder mask in the black color, and this may be because of some reasons as shared earlier. The main reason being the fact that reflected light may affect how a circuit operates; thus the black color makes sure this doesn't happen.

 

black pcb1.jpg

 

The black PCB is considered prestigious by those who use it as compared to the other colored PCB’s. In fact, even Apple uses the black PCB in the devices. It has gained much popularity even though the green PCB has still been the most used color.

 

The black PCB is made up of the black solder mask. The black solder mask is beneficial in the absorption of heat during the reflow. It depends on the user whether scaling up or down of the temperature is required to make the sensors used in the circuit safely.

 

The silkscreen of black PCB is also prone for the turning light into other colors such as brown for the heat absorption.

 

Manufacturers decide the color be used for the Printed Circuit Board as early as a molten stage. That is when it is most convenient and easy to apply the right color for the PCB. The black color mostly uses in the high-end devices as compared to the green one.

 

1.2 Black PCB Solder Mask

The solder mask is the most vital component or material required for the production of Printed Circuit Boards.

 

The solder mask is also known as the solder resist, and its primary purpose is to lacquer or varnish the entire surface of the PCB on both top and bottom for the formation of the protection layer which is permanent and the traces of copper are to be printed over it.

 

The solder mask is the primary agent to prevent the solder from coming in between the conductors and is also responsible for the creation of short in the circuit. The layer is also responsible for offering protection against the environment as well.

 

The solder mask of a black PCB, therefore, is colored black and this is done during the molten stage. The black solder mask is applied when the reflection of light is not wanted. The solder mask is, therefore, one of the most critical parts of the Printed Circuit boards.

 

black pcb6.png

 

Without a solder mask, as stated above, the circuit would have shorts and thus be inefficient in operation. The solder mask helps to prevent such a situation from taking place. The black solder mask is used in display systems where light is not supposed to be transparent.

 

There are some circuits where light reflection is not needed. In such circuits, the application of the black solder mask becomes of great importance. The mask absorbs heat during reflow. It means that you have to either reduce your profile or ensure that the temperature sensor has been placed on the board.

 

The other thing that would be required when coming up with the black solder mask is sufficient light. Since it is not easy to see the circuit, the black solder mask needs the adequate light that can be angled well for the manufacturer to see the board.

 

The inspection process for a black Printed Circuit board requires powerful magnification so that the circuit can be appropriately seen without strain. The green solder mask may be easy to inspect and manufacture since the circuit remains visible during its construction and even inspection.

 

The process of applying the black solder mask is not something you can do at home as a DIY process. The methods used are involved, and thus that would not be an efficient way to achieve your goal. You can, however, use the DIY method for simple boards but still, the quality will not be assured.

 

When it comes to the more complex Printed Circuit Boards, the process of applying a solder mask is not that easy. The first thing that you should be aware of is that there are stringent regulations that limit the production of such devices. Therefore the standards must be adhered to if you are to go commercial.

 

The manufacture of the solder masks is a process that has different stages that one must follow keenly. In these stages, the use of technology is professional and has high accuracy. In the process of manufacturing complex PCBs, they often use the software such as sprint layout.

 

The process of manufacturing the black solder mask starts with the cleaning of the board. The board is thoroughly cleaned after that the solder mask ink coating takes place. In this case, the black color is applied to the board before the pre-hardening phase.

 

After the pre-hardening phase comes to the imaging and hardening phase, which is followed by the developing phase. In the developing phase, software such as the sprint layout is made use of before final hardening and cleaning.

 

1.3 Matte Black PCB

The matte black Printed Circuit Board has become quite common in the recent times mainly due to its cool appearance. It is considered to look quite attractive to the eye and is preferable to the plain black PCB.

 

The gloss solder masks are also quite good and a suitable choice for Printed Circuit Boards but in this case, we will focus on the matte black PCB.

 

These days, unlike the past days, you can custom order the color of your PCB from the manufacturer instead of them just making the color they would want to. The good thing is that the matte black variety does not affect the functioning of the board in any way.

 

The use of matte black in PCB's gives the board a duller and softer finish as compared to other colors. This makes it also not to reflect much light that bounces on it and instead looks washed out when exposed to heavy light.

 

The matte finish can present some scratches for your board which can quickly be noticed and seen. They, however, look dull and don't shine as much. It makes the boards coated with matte black easier to see in light scenarios.

 

One advantage of the matte black PCB is that you can quickly detect problems on the board that has this variant of color.

2、Black PCB Board

The black PCB board is made from the use of a black solder mask. The solder mask that can also be referred to as a solder resist is a thin layer that covers copper traces. No matter the PCB design software that you may want to use say the sprint layout software, the solder mask is optional.

 

black pcb 0.png

 

The sprint layout software among other software can provide an automated solder mask. That's made possible by designing a solder mask through completing and filling out some parameters. It works just as efficiently as the traditional solder mask.

 

The solder mask is a vital part of Printed Circuit Boards determines the performance of the boards. It, therefore, prevents different problems in the circuit. Some solder mask fault issues may affect the entire circuit board, and they include the following:

 

       • Excessive openings.

       • Insufficient solder mask opening.

       • Mismatching between some openings in the circuit board.

 

The above PCB issues can be avoided when the process is done efficiently and with accuracy. In most cases, the PCB’s that have the above problems are the ones that have been made using the DIY process instead of being manufactured with the right facilities.

3、Black PCB Material

Printed Circuit Boards are usually made from different materials. Software such as the sprint layout software is used to design the PCB’s. The black PCB is made out of a black solder mask. Most solder masks are made from resin material due to the following reasons.

 

       • The resin is perfect regarding humidity resistance.

       • The resin is an excellent insulator. It offers excellent insulation for the board.

       • The resin is solder resistant.

       • The resin can bare and overcome high temperatures meaning it can stay on heated places without necessarily being affected.

       • Because of aesthetics reasons.

 

black pcb4.jpg

 

The procedure of applying resin on a Printed Circuit Board is as follows:

 

       1. Clean The Board.

Before you apply resin on the board, you must make sure that the board is clean and free from rust to avoid any functionality issues. The cleaning process can also help in removing some bit of oxidization.

 

       2. Apply Resin.

Once you have cleaned the board, you can now place it on a piece of blank film and release resin onto it by the use of a plunger or syringe, whichever that would work well for you. The size of the PCB will determine how much resin you can get to use. Without precise measurements, you can either put too much or too little resin.

 

       3. Spread The Resin.

In this process, you can use another piece of transparent blank film by laying it over the resin that has been placed on the board. That assists the resin in spreading all over the board effectively without missing any spot. A piece of glass can then be placed on top of the film to ensure that the resin has been distributed well.

 

       4. Squeegee The Resin.

In this step, you can make use of a squeegee to distribute the resin on the hard to reach areas, especially on the corners. You should be careful not to apply too much pressure, or otherwise, you may get bad spots on the board that may generally affect the functioning of the circuit board.

 

Another thing you should avoid is creating any air bubbles in due process as this may also affect the normal operation of the board. It is a process that needs time, and you shouldn't, therefore, be in a hurry to perform it otherwise you might do a shoddy job that will end up costing you.

 

       5. Place The Mask.

After you have applied the resin, you can then place the solder mask film over the Printed Circuit Board. The process is then followed by the alignment of the film which is yet again another important process that you shouldn't avoid. To give the film more grip, you can add a bit of alcohol to the back of the mask to make it stick on the clear film more professionally and conveniently.

 

       6. Expose The UV Resin.

Here you can use a UV flashlight that can cover the whole PCB and focus it for about 10 minutes keeping a distance of around 2-3 inches.

 

       7. Peel The Film.

After all, you can then gently peel off the film.

4、Black PCB Coating

Black PCB coating has some advantages. First of all, it boosts the safety of electronic devices. 

 

The coating can either be done in a manual process or automatically be depending on your choice. When you perform the coating procedure, and it happens that it penetrates to the shadowed areas, you can still rectify this through secondary means.

 

There are different types of coats that you can use for the black PCB. The following are some of the coats available to choose from:

 

       • Acrylic. This coat provides the PCB with good protection and sufficient elasticity. They are not complicated and thus can be applied and re-worked on easily. They can also be easily removed whenever the need may arise.  

 

       • Urethane. These coats are popular for their exquisite protection properties. They protect PCB's against chemical and mechanical attacks that are prone to happen. They are also suitable for moisture resistance.

 

       • Silicone. These coats provide the PCB’s with great temperature protection. They are also appropriate for chemical resistance.  

 

       • Varnish. These coats are moisture resistant and have high insulation and stability properties.

 

The above coats have different properties that would be a determinant of which one to choose. They, for instance, have different mechanical, chemical and moisture resistance properties.

 

Such properties are essential to consider when selecting the coat of your choice as they go a long way in ensuring your PCB lasts longer.

 

The resin that is used should also be qualified to ensure that your PCB and its components are safe and thus do not get affected in the long run.

 

Black PCB coating is helpful in protecting the circuit against factors in the environment that would somewhat affect its general performance.

 

Some of the conditions that may affect the functioning of the PCB include temperature and humidity which of course fluctuate on a day to day basis; this begs the importance of planning of time by using the right coat for your PCB.

 

The coats, therefore, have a variety of functions that they perform for the Printed Circuit Boards. Some of these functions include the following:

 

       • They reduce the stress that the environment may put on the PCB during assembly.

 

       • They provide insulation for the PCB.

 

       • They prevent the PCB’s from being affected by chemicals and mechanical attacks.

 

       • They reduce some potential factors that may inhibit the performance of the PCB’s.

 

black pcb coating.png

5、Conclusion

We do hope that you have learned and gained knowledge of the black PCB and the sprint layout software. The black PCB has its advantages that you can consider when choosing the color of the solder mask.

 

One of the main advantages of using a black Printed Circuit Board is that they are appropriate in circuits where the reflection of light is not required. Such circuits would need the use of a black PCB to function effectively.

 

The black PCBs can be coated with different coatings depending on which one would suit your needs. It is vital to consider properties such as chemical resistance, mechanical resistance, moisture resistance among other factors that make the PCB suitable for use effectively.

 

The matte black PCB offers a good vision for errors that may be present on the PCB such as scratches thus making it easier for you to rectify.

 

In case of any inquiries, you can contact us through the following leads:

 

       • sales@wellpcb.com

 

       • www.wellpcb.com

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