PCBA circuit board design precautions
In the design process of PCBA board, the following matters need to be paid attention to to ensure the rationality and reliability of the design:
1. Demand analysis:
• Clear product functional requirements, performance indicators, use environment, etc., which is the basis of design.
2. Schematic design:
• Draw circuit schematic diagram according to requirements to ensure correct circuit logic and reasonable signal connection.
3. PCB design:
• PCB layout and routing according to the schematic diagram, reasonable arrangement of component positions and wiring to ensure the rationality of electrical performance and mechanical structure.
• Reasonably plan the routing of power and ground to avoid interference and noise.
• Pay attention to signal integrity to ensure the transmission quality of high-speed signals.
• Set the bypass capacitor and decoupling capacitor correctly to improve circuit stability.
4. Component selection:
• Select the right electronic components, to consider the performance, cost, availability and other factors.
• Ensure compatibility between components and match with the circuit board.
5. Thermal Management:
• For components with large heat output, the location should be reasonably arranged to ensure good heat dissipation.
• Consider the thermal conductivity of the PCB to avoid local overheating.
6. Mechanical structure:
• Ensure that the PCB size and shape meet the product requirements and is easy to install and use.
• Consider the installation method and space requirements of components to avoid interference.
7. Manufacturing process:
• Follow the requirements of PCB manufacturing process to avoid production difficulties caused by unreasonable design.
• Pay attention to the selection of PCB board thickness, aperture and other parameters.
8. Quality control:
• Use reliable components to reduce the risk of failure.
• Conduct environmental adaptability tests to ensure that products can operate reliably under a variety of conditions.
9. Maintenance and testing:
• The design should consider the convenience of maintenance, easy to replace components and fault diagnosis.
• Set test points and marks reasonably to facilitate the operation of maintenance personnel.
10. Cost and environmental protection:
• Minimize material costs and processing costs while meeting performance requirements.
• Optimize design to reduce unnecessary components and process steps.
• Select materials and processes that meet environmental standards to reduce environmental impact.
PCBA circuit board production process
The production process of PCBA (Printed Circuit Board Assembly) board covers the entire process from bare board to final electronic product assembly, the following are the main steps:
1. Raw material preparation:
• Check and prepare PCB (bare board) and all electronic components.
• Solder Paste onto the pad of the PCB by screen printing. Solder paste is a mixture of solder and flux used to connect component pins to PCB pads.
2. Patch:
• Use an automatic mounter to precisely place the surface mount component (SMD) on the PCB pad printed with solder paste. The placement machine picks up and places components through a vacuum nozzle or a robotic arm.
3. Reflow welding:
• The PCB with the attached component is passed through the reflow furnace, where the solder paste melts and cures at high temperatures to form a reliable electrical and mechanical connection.
4. Optical Inspection (AOI) :
• Check the welding quality on the PCB with automatic optical inspection equipment to detect welding defects, misalignments, missed stickers, welding Bridges, etc.
5. Plug-in components insertion:
• For through-hole plug-in components (such as electrolytic capacitors, high-power components, etc.), insert the components into the through-hole of the PCB by hand or automated equipment.
6. Wave soldering:
• For through-hole insert components, solder is melted by wave soldering process and connected to component pins and PCB pads by wave crest.
7. Cleaning:
• Remove flux and other contaminants from the welding process by chemical or ultrasonic cleaning to ensure that the PCB surface is clean and prevent electrochemical migration and corrosion.
8. Test:
Perform online testing (ICT) or functional testing (FT) to verify the electrical performance of the board and ensure its functionality and reliability.
9. Rework and repair:
• For problems found during inspection and testing, repair them by hand welding, rework station or other equipment to ensure that all PCBS meet quality standards.
10. Assembly:
• Assembly of the tested PCBA into the final product, which may include attaching enclosures, installing heat sinks, securing connectors, etc.
11. Final Test:
• Perform final tests on fully assembled products to verify their overall functionality and performance to ensure full compliance with specifications and quality requirements before leaving the factory.
12. Packing and shipping:
• Clean and pack qualified products, label them as required, and protect them against static electricity and moisture.
In summary, the production process and design considerations of PCBA board are key links to ensure product quality and reliability. In the design and production process, it is necessary to fully consider various factors and follow the corresponding process and precautions to ensure the quality and performance of the product.
English
Chinese