What is a presensitized PCB

What is a presensitized PCB

Presensitization is a method of processing PCBs (printed circuit boards) that involves the use of UV exposure. Presensitizing PCBs with UV light is a fun and unique way to approach your DIY electronics projects. However, there are many steps involved!

Before you start, ask yourself if you like the idea of a lighter PCB fabrication process, and if you like the idea of trying your own DIY electronics project. If your answer is yes, it's worth learning more about presensitized PCB manufacturing.

In this guide, even if you've never done it before, you'll learn more about the process of presensitizing PCBs, photosensitive PCB boards, and how to handle presensitized PCB boards from scratch.

Introduction to Presensitized PCB

If you love electronics, are a pro, or just an expert electronics tinkerer, you've probably read all about handling PCBs. Manufacturing your unique PCB can be a tricky process that is very labor-intensive, better suited to professionals! But maybe you want to use custom board artwork to create a unique PCB? If this is the case, then creating a presensitized PCB might be right up your alley.

You might be asking yourself, what's the point of presensitizing the PCB in the first place? The main benefit of presensitization is that it can be more accurate than other PCB processing methods such as toner transfer methods.

If you are an electronics hobbyist and enjoy modifying unique pieces, creating pre-sensitized PCBs can also be a lot of fun.

Another huge benefit of presensitizing PCBs is that the cost of the process is very low. The PCB presensitization process reduces costs by eliminating manufacturing steps, so you can afford experimental creative passion without worrying about running out of budget!

What exactly is a presensitized PCB?

A pre-sensitized PCB is a special type of PCB in which the surface of the board contains a unique coating of photosensitive material. This pre-sensitized PC board allows you to easily apply unique custom designs by transferring (or "burning") the image using UV light.

A presensitized PCB is just like a normal copper clad PCB, the main difference is how the design is transferred to the board.

Traditional (copper clad) PCB boards transmit images by:

*Toner transfer method

*Inkjet mask method

*Dry film photopolymer method

Using an innovative liquid film approach

Presensitized PCB boards transmit images by:

*Exposure to UV light

Pre-sensitized PCBs have a special photosensitive coating added during the manufacturing process. Photosensitive coatings are very sensitive to light! A "peel-off" layer protects the unique photosensitive coating from accidental light exposure. Only remove the peelable protective layer just before exposure to UV light!

PCB Printing Preparation Process

Remember that PCB printing requires a lot of effort, patience and testing! So, keep in mind that mistakes can be made when printing a PCB board with a photosensitive PCB for the first time. So creating multiple breadboards on the first attempt at any manufacturing test can be a genius idea.

It's also a good idea to familiarize yourself with a reliable PCB manufacturer, so you can rest assured that you're using reliable components and that your supply chain won't diminish, fade, or become a problem during production!

PCB preparation

When working with a presensitized PCB, the first thing to do is to take a close look at the thick gray film on both sides of the board. The film is designed to protect the circuit board itself from UV exposure.

Remember that the board will be very sensitive to light when you remove the film, so don't remove the film until you're ready to expose it to UV light right away!

Before removing the protective film, be sure to cut the board to the specifications of the project. The PCB board and protective film are surprisingly durable, so you don't have to worry about damage. Cutting the PCB to a larger size than the pre-sensitized pattern can be a very sensible move, as this added space is very useful during the etch stage of the board.

Now that your boards are cut and ready, it might be a better idea to prepare a second (or third) copy of the board, so you can experiment with the exposure process and try to get the best results. Remember, practice makes perfect, and using presensitized boards for the first time can be tricky!

PCB exposure

PCB exposure is usually carried out in an exposure box. An exposure box is just a box with a UV light. You can create a unique exposure box yourself, or search your favorite electronics store to find a pre-assembled box. Exposure boxes are available on both Amazon and eBay, but if you're a true electronics hobbyist, creating your own may be more fun.

One of the most important things to remember is that if the glass on both sides of the exposure box gets dirty, those smudges can easily transfer to the PCB board during the exposure process!

There is nothing more annoying and frustrating than an ugly spot, spec, blemish or blemish on a perfect board. So it goes without saying that the glass and UV lamps in the exposure box are completely clean. Before starting the exposure process, you should wipe the glass of the exposure box with a microfiber cloth and a mild detergent to ensure the surface is free of contamination.

Also keep in mind that almost any light source will have an effect on your board when removing the grey protective film from the pre-sensitized board. Your board is very sensitive to light! So it's best to work in a relatively controlled area with no bright lights (other than, of course, the UV in the exposure box).

When you're sure the exposure box is clean and you've eliminated all extra strong light sources, it's time to remove the protective film from either side of the presensitized plate.

Now that the desensitized board has had its protective film removed, it is important to remember not to touch the surface of the board. Circuit boards are very sensitive, so be careful not to get them dirty or expose them to any sharp, bright lights!

Carefully place the top and bottom of the pre-sensitized PCB artwork layer on the board so everything is perfectly aligned and centered. Once you are satisfied with the alignment, place the presensitized plate in the exposure box. Don't turn on the lights!

After placing the board in the exposure box, it is best to place a thin, flat piece of glass on top of the board. The reason for this is so that the artwork layer can touch the surface of the board and to ensure that both the board and the artwork layer are flat.

Once you're sure your artwork layers are perfectly aligned on the board, and once you're sure your artwork is flat on the board, turn on the exposure light.

The time required for the exposure process will vary depending on the intensity of your light and the overall design of your exposure box. Typically, you can expect the exposure process to last anywhere from 1 minute to over 10 minutes! This difference is why experimentation is so important, and why we recommend that you create many different copies of the board!

Pre-Sensitive PCB Conclusion Paper

congratulations! You now have a better understanding of pre-sensitized PCBs, and you also realize that creating custom PCBs can be a truly unique, fun, and inexpensive way to experiment with all your love for electronics.

Without a doubt; being able to manufacture PCBs is probably one of the most important skills for an electronics hobbyist. If you master this skill, you can save a lot of frustration, time, and money while still having a lot of fun!

To recap, here are the advantages of creating a unique presensitized PCB:

1. A very handy skill for electronics DIY tinkerers.

2. May be a good way to make unique PCB designs.

3. Steps in the manufacturing process can be eliminated, making it faster and cheaper.