What is PCB screen printing?

PCB screen printing is mainly text-based information, including circuit points, components, circuit symbols, etc. The silk screen signal varies depending on the size of the PCB. If space is limited, you need to consider the most critical information first.

PCB screen printing mainly includes the following:

Component Reference Mark

Polarity Marking

Pin 1 Marking

Component Boundary

Company Logo

Manufacturer's mark

Warning Symbol

Season No.

Version Number

Date Code

2. PCN screen printing all operation process
1. Design screen printing

Use EDA class software to design the screen printing layer. Includes all necessary markings, symbols and text required to identify and assemble components on the PCB. It is then exported in a format that the manufacturer can use.

2. Manufacturing PCB

The PCB manufacturing process involves printing a layer of copper on the substrate, drilling holes for the components, and then etching away the excess copper to create the PCB, which may have different shapes and patterns.

The screen is printed on top of the copper layer using a specialized screen printing process.

3. Application of screen printing

After the PCB manufacturing is completed, the screen layer is printed using a screen printing process, which here involves creating a template for the screen printing design. Create a template for the desired image by applying a photographic emulsion to the grid.

4. Curing ink

After applying the screen printing layer, the ink must be cured to ensure that it adheres correctly to the PCB substrate, usually by exposing the PCB to high temperature or ultraviolet light for a specified period of time.

5. Check and test PCB

Finally, check and test the PCB to ensure that the screen printing layer can be applied normally, and the necessary marks and symbols are printed. Errors and omissions in screen printing can lead to assembly errors or functionality.

This gap can be compared to ensure that the PCB has the correct marking, which can be easily identified, thereby reducing the risk of errors in the assembly process and improving the overall reliability of the finished product.

3. PCB screen printing design
Here are some notes for PCB screen printing design:

1. Component direction and polarity

The direction on the screen marks the direction in which the component is soldered, usually represented by a dot, identifying pin 1 of the IC. If it is an LED and a diode, it is "" or "C", C is the cathode and A is the anode. In the case of capacitance, the half-shaded circle indicates negative polarity and "" indicates positive polarity.,

2. Direction overlap

Edit the text direction of component references, part types, etc. to ensure that they are all in one direction for easy reading, and you can also set top and bottom screen printing.

Check for text overlap before rotating the text and adjusting the component reference designator. As shown in the figure below, the directions of the markers are inconsistent and overlap. There is no way to refer to it when assembling and troubleshooting. Therefore, at the time of design, if such an overlapping situation is encountered, it is necessary to rotate and move the component reference indicator to the correct direction and position through the corresponding component.

Check whether the component reference indicator placed on the PCB pad overlaps the pad. The first mark circled in the following figure overlaps with the pad, and there is no way to refer to the group leader and troubleshooting. It is therefore necessary to move the marker to the blank position of the corresponding component.

Check the marking on the through hole. The second component tag in the following figure. Since there is no way to print without a tent through hole, but when you use a solder resist layer to cover the tent through hole of the through hole, you cannot use it as a test point, and it is best to move it to the side of the component.

Check that the reference mark is placed so that the reference mark is below the object after welding the component. If there is a mark under the component, move the empty space next to the component, as shown below.

3. Additional Marking

The added additional marks can better display the direction of the components. If the following figure shows, in addition to the original marking direction of the components, you can also add triangular, circular and other shaped marks to display the direction of the I/O components.

A polarity mark is placed outside the component object mark, as shown in the following figure. Generally, components with polarity such as electrolytic capacitors, diodes, LEDs, etc. need to be marked with this.

Measurement marks for the number of pins and lines on the IC can be added in silk screen printing,

4. Screen printing process

It is very important to choose the right screen printing work. The printing method will affect the design parameters, such as the size, gap and position of the screen printing on different component pads, traces and through holes.

5, the appropriate screen printing font

Choose the right font, readability is high, such as silk screen size, height, color, font, etc. The most common dimensions are 35mil height and 5 mil line width, and 25 mil height and 5 mil line width