PCB News - How to improve the reliability of PCB equipment

Technical measures to improve the reliability of PCB equipment: plan selection, circuit design, circuit board design, structural design, component selection, PCB manufacturing process, etc., and the specific measures are as follows:

(1) Simplify the design of the scheme.

When designing the scheme, under the premise of ensuring that the equipment meets the technical and performance indicators, the design should be simplified as much as possible, and the circuit and structural design should be simplified, so that each component becomes a simple design. The modular design method popular in the world today is an effective measure to improve equipment reliability. The block function is relatively single, and the system is composed of modules, which can reduce the complexity of the design and standardize and standardize the design. A large number of facts inside and outside have proved this point, and product design should adopt a modular design method.

(2) Adopt modules and standard components.

Modules and standard components are products that have been proven to be highly reliable after a large number of tests and extensive use, which can fully eliminate equipment defects and hidden dangers, and also bring convenience to replacement and repair after problems occur. The use of modules and standardized products can not only effectively improve the reliability of the equipment, but also greatly shorten the development cycle, providing extremely favorable conditions for the rapid modification and installation of the equipment.

(3) Improve integration.

Choose a variety of large-scale and very large-scale integrated circuits with strong functions and high integration to minimize the number of components. The fewer the components, the fewer the hidden dangers. In this way, not only can the reliability of the equipment be improved, but also. Can shorten the research and development cycle.

(4) Derating design.

Derating design means that the component works under the condition of lower than its rated stress, which is an effective method to reduce the failure rate of the component. Therefore, when setting the juice, the working voltage range of the component is Temperature characteristics, electrical characteristics and parameters are all derated to reduce the failure rate of components under various stress conditions.

In derating design, the factors to be considered for different components are different: some are voltage range, some are current, some are temperature, some are frequency, some are vibration, and so on. Under normal circumstances, the voltage, frequency, temperature characteristics of the capacitor, the power of the resistance, the current and frequency characteristics of the inductor, the junction current, junction temperature or The fan-out coefficient, the switch of the power supply and the withstand voltage/current and temperature performance of the main power supply cable, the frequency characteristics of the signal cable, and the use of heat sinks, connectors, module power supplies and other devices require derating design .

(5) Choose high-quality devices.

Components are the basic components of equipment, and their quality will directly affect the reliability of the equipment. Military communication equipment should use products above industrial grade as much as possible, preferably military products, and strictly carry out aging screening before getting on the machine to eliminate early failure devices.
(6) Make full use of software resources.
Due to the flexibility of software programming, software resources should be fully utilized in the design. At present, there are relatively many software debugging methods and tools, which are easy to locate faults and design problems, and the resolution cycle is relatively short. Making full use of software resources is an important method to improve reliability.

(7) Reliable structure, mature and advanced technology.

In the circuit and structure design, the number of connectors and metallized holes should be minimized. Circuit components and chips should be directly soldered on the printed board as far as possible. Surface mount devices should be selected and surface mount technology should be used to avoid poor contact., To ensure the reliability of the equipment.

(8) Thermal design.

Excessive temperature is one of the important factors that cause the equipment performance and reliability to decrease. For this reason, thermal protection measures should be taken to control and reduce the temperature rise of the equipment during operation, ensure good heat dissipation, and improve the thermal reliability of the equipment.

Too low temperature will also cause degradation of equipment performance and reliability, and some components will not work normally when the ambient temperature is too low. Therefore, equipment used in a low-temperature environment must also be subjected to low-temperature testing. The temperature conditions and environment of the equipment must be considered when designing.

(9) Electromagnetic compatibility design.

When the equipment is working, it will be interfered by many electromagnetic fields, both natural and man-made. This is especially true for military equipment. In modern high-tech electronic warfare, a very important technical means is to locally emit high-energy electromagnetic waves to destroy the components in the opponent's equipment, thereby causing the equipment to fail. To this end, effective shielding, filtering and other anti-interference measures should be taken to prevent noise and interference electromagnetic fields from interfering with the equipment to ensure reliable operation of the equipment.

(10) Anti-vibration design.

The equipment will be affected by various vibrations and shocks during use and transportation, which will affect its reliability. For this reason, the mechanical strength and rigidity of the equipment should be improved, and vibration damping and buffering measures should be taken to strengthen the equipment's resistance to vibration and shock. The ability to improve the reliability of the equipment.

(11) Adopt fault indication device.

Design fault detection circuits and fault alarm devices to find faults in time, thereby shortening the troubleshooting time of the equipment.

(12) Simple operation and convenient maintenance.

The function of operation and maintenance in the equipment is one of the main factors to ensure the reliability of the equipment. In the design, plug-in units and modules should be used as much as possible, while modularization, standardized structure and quick disassembly structure should be adopted to facilitate operation and maintenance. Facts have proved that the modular structure of the equipment can greatly simplify operation and facilitate maintenance.