PCB printing includes the following:
Preparation of Substrate: Select suitable substrate, such as FR4, CEM-1, etc., and clean it to remove surface dirt and impurities.
Coating: Pour the coating on the substrate and use a squeegee or coating machine to spread the coating evenly on the substrate.
Drying: Place the coated substrate in a drying oven and heat to the proper temperature to dry and cure the paint.
Cooling: Remove the dried substrate and cool it naturally to room temperature.
Processing: Process the coated and printed substrate according to the need, such as stamping and cutting.
Inspection: Conduct quality check on the processed substrate, including the thickness, uniformity, adhesion and other indicators of the coating.
Packaging: The inspected and qualified substrates are packaged to prevent contamination and damage.
In the PCB coating and printing process, the following points need to be noted:
Selection of Coating: Select the appropriate coating according to the need, including color, viscosity, curing temperature and other indicators.
Uniformity of Coating: In the coating process, it is necessary to ensure the uniformity of the coating to avoid uneven coating and leakage.
Drying Temperature and Time: Proper drying temperature and time are the key factors to ensure the quality of coatings, and need to pay attention to control.
Processing Precision: In the process of processing, it is necessary to ensure the precision and quality of processing to avoid errors and defective products.
Inspection Standard: In the inspection process, it needs to be carried out according to the unified standard to ensure the consistency and reliability of product quality.
Packaging Protective Measures: In the packaging process, the need for effective protective measures for the substrate to prevent contamination and damage.
The above is the basic process of PCB coating and printing and precautions, the specific operation may vary depending on the actual situation.
Characteristics of The PCB Printing process
In the PCB printing process, the following points need to be noted:
Uniformity: The uniformity of PCB coating and printing is very good, which can ensure the stable transmission of current and improve the performance of electronic products.
Stability: PCB coating and printing materials and processes can enhance the stability and durability of the PCB to ensure a long service life.
Adhesion: PCBcoating and printing of strong adhesion, can ensure that the coating and the substrate of the close combination, to avoid peeling, blistering and other phenomena.
Protection: PCB coating can protect the PCB board from environmental factors, such as moisture, oxidation, etc., which prolongs the service life of the PCB board.
Aesthetics: PCB printing can be customized according to the design requirements of the color and style, so that the PCB board is more beautiful and generous.
Functionality: PCB coating can also give the PCB board some special functions, such as thermal conductivity, fire prevention, etc., to meet the needs of different products.
Reliability: PCB coating and printing process and materials undergo strict quality control and testing, which can ensure the stability and reliability of the coating.
PCB coating and printing has the characteristics of uniformity, stability, adhesion, protection, aesthetics, functionality and reliability, which can enhance the performance and quality of electronic products.
PCB Printing Process Considerations
In the PCB printing process, the following points need to pay attention:
Ink Selection: The appropriate ink should be selected according to the PCB material and design requirements to ensure the quality and stability of the coating and printing.
Coating Thickness: The coating thickness should be controlled within the appropriate range, too thick or too thin will affect the coating quality and precision of the circuit board.
Coating Uniformity: The printing process should ensure that the entire PCB board surface coating thickness is consistent, in order to avoid uneven board surface or uneven coating.
Graphic Integrity: In the coating process, should ensure that the circuit graphics are not damaged or deformed, in order to maintain the design accuracy and reliability of the circuit board.
Ambient Temperature and Humidity: The ambient temperature and humidity during the coating and printing process should be controlled within a suitable range to avoid affecting the viscosity of the ink and the quality of the coating and printing.
Ink Drying: Drying is required after printing to ensure that the ink adheres firmly. Drying conditions should be selected according to ink type and PCB material.
Prevent Clogging: During the coating and printing process, the screen plate should be kept clean to avoid poor coating and printing due to screen plate clogging.
Safety Measures: Appropriate safety equipment, such as gloves and protective glasses, should be worn during the production process to ensure the safety of employees.
Quality Inspection: Quality inspection should be carried out during the coating and printing process, such as visual inspection and thickness measurement to scrutinize the circuit boards in order to ensure the coating and printing quality and reliability of the circuit boards.
In addition, the following matters need to be noted:
A. When applying coatings to the PCB, generally connectors, software sockets, switches, heat sinks, heat dissipation areas, plugboard areas, etc. are not allowed to have coating materials, and it is recommended to use tearable solder resist to cover them.
B, The thickness of the film layer depends on the application method. With a high thinner addition, the adhesive viscosity is low and the thickness of the applied adhesive is thin; conversely, the adhesive viscosity is high and the thickness of the applied adhesive is thick.
C. All coating operations should be carried out under conditions of not less than 16°C and relative humidity of less than 75%. PCB as a composite material will absorb moisture. If it does not get wet, the three-proof paint can not play a sufficient protective role. Pre-drying and vacuum drying can remove most of the moisture.
D. Repair has been coated devices, just soldering iron directly in contact with the coating can be removed from the component, after installing a new component, and then the area with a brush or solvent cleaning, and then dry, re-coated with paint.
PCB coating and printing process requires attention to many issues, the need for board manufacturers with advanced equipment and technical strength and strict quality management system to ensure that the production of circuit boards to meet customer requirements. At the same time, the design stage needs to take into account the performance and reliability requirements of the circuit, rational arrangement of component layout and wiring and other elements. In addition, attention also needs to be paid to environmental protection and safety measures and other aspects of the problem.
