عملية طباعة شاشة ثنائي الفينيل متعدد الكلور

عملية طباعة شاشة ثنائي الفينيل متعدد الكلور

PCB screen printing is a sub-process of solder masking and others, like baking, UV exposure, and development. Most people consider it the most refined among the four categories because of its general effect on the product’s grading and reliability.

The entire PCB silk printing process comprises 32 steps that can further be grouped into six broad processes. These processes may differ in real scenarios based on the PCB material, quality requirements, and expenses.

Let us dive deeper into each of these 6 processes.

1. PCB Silkscreen Design

In this process, the artwork you designed to be printed on your board is prepared. You can use computer-aided software EAGLE to carry it out easily and creatively.

As part of the PCB design package, the silkscreen section allows you to design the silkscreen layer, circuitry, and other design elements pleasantly. The yellow rectangular shape is the silkscreen outline. You can find it on top of the grey package measurement lines.

Once you have chosen your silkscreen menu, you can proceed with the design easily. You can turn the component placement points into texts via various menu options available.

2. Board Preparation

Once you have finalized your CAD blueprint, you can proceed to the hardware implementation. Here, you need to carry out some steps diligently to get a high-quality PCB.

First, select the board type you will use in the production process. After that, clean, tape troll, and handle your board well to prepare it for printing. Print the design you prepared in step one on transparent paper. After that, place them on dry silk fabric the way you would want them to look on the actual PCB.

Ensure you maintain the PCB design paper at its original position. To achieve this, mount the designs firmly on the surface with clear tape. Afterward, turn the whole setup (silkscreen and the mounted designs) to face downwards. Cover the upper part with opaque cardboard.

Expose the lower part to UV light for approximately 15 minutes to develop the board silkscreen artwork fully. Then use pressurized water to wash away the emulsion sections that were not cured and expose the designed silkscreen template.

3. Silkscreen Printing

This is where the actual silkscreen printing takes place. For this to happen, you have to fix your board on a printing machine. Consequently, the machine moves the screen upwards, downwards, and sideways for directional printing. The design you created on Eagle is now etched on the board.

Now, to print the silkscreen on the board, place the etched PCB under the silkscreen fabric. Ensure it aligns well with the silkscreen artwork on top. Additionally, fix the PCB properly to ensure it does not move during the application process. This can be achieved using stoppers at the PCB edges.

مقبل, apply the silkscreen UV curable ink evenly on top of the artwork using a squeegee. From there, dry the PCB for approximately ten minutes with a drying oven. The texts or marking are clearly displayed on the board surface now.

4. Handling Procedures

At this point, you have finished screen printing your board. لكن, it would be best if you practiced proper handling to maintain the PCB quality. This is why the biggest steps are done in handling procedures. You should conduct about 12 steps to ensure that your PCB quality is not affected by the silkscreen printing process negatively.

5. Inspection Procedure

You should carry out an inspection process during the handling steps and after the processing steps. The aim is to determine the quality of the board panels you created visually. Besides, this process ensures that the printed information is readable by the human eye. In small boards, ensure you print all the essential information first.

6. Silkscreen Treatment

This is the last step of the PCB screen printing process. Here, you treat your silkscreen print and inspect whether it is ready for use. This will be determined by the quality of the silkscreen process.

Mix an emulsion with a developer in a ratio of about 10:1; if possible, mix them in a dark room. Apply the mixture on the silk fabric surface using a wide squeegee. It is recommendable to apply two layers on every side to create four layers in total. The layers must be even and devoid of spaces or bubbles. It would be best if you allow them to dry naturally, or you can speed up the process with a drier.