Things to Consider When Making PCB Circuit Boards
At this stage, in the field of electronic product processing, PCB boards are indispensable as one of the most crucial electronic components. Currently, there are various types of PCB boards, such as high-frequency PCB boards, microwave PCB boards, and other specialized printed circuit boards that have gained market recognition. PCB board manufacturers have specific production processes for different types of boards. However, in general, the production and processing of PCB boards need to address several key aspects:
1. Consider the Choice of Substrate
The base material of PCB boards can be categorized into two types: organic and inorganic materials. Each material has its unique advantages. Therefore, the choice of substrate type must account for various properties such as dielectric characteristics, copper foil type, base groove thickness, and production and processing attributes. Among these, the thickness of the surface copper foil is a critical factor influencing the performance of the printed circuit board. Generally, a thinner thickness facilitates easier etching and improves graphic precision.
2. Consider the Production Environment
The indoor environment of the PCB board production and processing workshop is also crucial. Controlling the working environment’s temperature and relative humidity are particularly important. Significant fluctuations in temperature may cause damage to the holes on the base plate.
1. If the relative humidity of the air is too high, it adversely affects the performance of substrates with high water absorption, particularly in terms of dielectric properties. Thus, maintaining appropriate indoor environmental conditions during PCB production and processing is crucial.
2. Consider the choice of technological process
3. PCB production is influenced by many factors. The number of layers, punching process, surface coating treatment, and other procedures all impact the quality of the finished PCB. Therefore, it is essential to carefully consider the indoor environment, production equipment characteristics, and adjust flexibly according to PCB types and production requirements.
4. In summary, PCB production and processing require careful consideration of substrate choice, production environment settings, and process flow selection. Additionally, the processing and blanking methods for PCB engineering materials must be selected with care, as they significantly affect the circuit board’s smoothness.
5. Damage characteristics of electronic components on PCB circuit boards
6. Resistance damage
7. Resistors are the most numerous components in electrical equipment, though they are not the most frequently damaged. Open circuits are the most common type of resistor damage. An increase in resistance value is rare, and a decrease is even rarer. Common types include carbon film resistors, metal film resistors, wire wound resistors, and fuse resistors.
8. The first two types are the most widely used. Low resistance (below 100Ω) and high resistance (above 100kΩ) resistors are more likely to be damaged. Low-resistance resistors often burn and blacken, making them easier to detect, whereas high-resistance resistors are rarely damaged. Wire wound resistors, used for high current limiting, may burn, turn black, or crack, but some show no visible damage. Cement resistors, a type of wire wound resistor, might break when burned out. Fuse resistors may blow off a piece of skin from the surface but generally do not turn black. These characteristics help in quickly identifying damaged resistors.
9. Electrolytic capacitor damage
10. Electrolytic capacitors are common in electrical equipment and have a high failure rate. Damage can manifest as complete loss or reduction of capacity, mild to severe leakage, or a combination of both. Methods to identify damaged electrolytic capacitors include:
11. (1) Visual inspection: Damaged capacitors may leak, leaving oil on the circuit board or capacitor surface. These capacitors should be discarded. Some capacitors bulge when damaged and cannot be used.
12. (2) Touch: Capacitors with severe leakage may become hot and should be replaced.
13. (3) Electrolyte inside capacitors can dry out from prolonged heat, reducing capacitance. Capacitors near heat sinks and high-power components are more likely to be damaged.
14. Damaged semiconductor devices such as diodes and transistors
15. Diodes and transistors usually suffer from PN junction breakdown or open circuits, with short circuits being more common. There are two main damage types: one involves deteriorated thermal stability, causing issues after prolonged use; the other involves PN junction characteristics deteriorating, which might not be apparent with an R*1k multimeter setting but may show abnormal forward resistance at lower settings.
16. Testing transistors involves measuring forward and reverse resistance with a multimeter set to R*10 or R*1. If the forward resistance is within normal range and the reverse resistance is high, the PN junction is likely intact. Otherwise, further inspection is necessary. Note that peripheral resistance can affect readings on low-range settings.
17. Damaged integrated circuits
18. Integrated circuits have complex internal structures, making any part’s malfunction critical. Integrated circuits may suffer from complete damage or poor thermal stability. To diagnose complete damage, compare pin resistances with a functioning IC of the same model. For poor thermal stability, cooling the IC with absolute alcohol while it is operational can help determine if the failure persists or resolves. Typically, replacing the IC is necessary for a definitive diagnosis.
At this stage, in the field of electronic product processing, PCB boards are indispensable as one of the most crucial electronic components. Currently, there are various types of PCB boards, such as high-frequency PCB boards, microwave PCB boards, and other specialized printed circuit boards that have gained market recognition. PCB board manufacturers have specific production processes for different types of boards. However, in general, the production and processing of PCB boards need to address several key aspects:
1. Consider the Choice of Substrate
The base material of PCB boards can be categorized into two types: organic and inorganic materials. Each material has its unique advantages. Therefore, the choice of substrate type must account for various properties such as dielectric characteristics, copper foil type, base groove thickness, and production and processing attributes. Among these, the thickness of the surface copper foil is a critical factor influencing the performance of the printed circuit board. Generally, a thinner thickness facilitates easier etching and improves graphic precision.
2. Consider the Production Environment
The indoor environment of the PCB board production and processing workshop is also crucial. Controlling the working environment’s temperature and relative humidity are particularly important. Significant fluctuations in temperature may cause damage to the holes on the base plate.
1. If the relative humidity of the air is too high, it adversely affects the performance of substrates with high water absorption, particularly in terms of dielectric properties. Thus, maintaining appropriate indoor environmental conditions during PCB production and processing is crucial.
2. Consider the choice of technological process
3. PCB production is influenced by many factors. The number of layers, punching process, surface coating treatment, and other procedures all impact the quality of the finished PCB. Therefore, it is essential to carefully consider the indoor environment, production equipment characteristics, and adjust flexibly according to PCB types and production requirements.
4. In summary, PCB production and processing require careful consideration of substrate choice, production environment settings, and process flow selection. Additionally, the processing and blanking methods for PCB engineering materials must be selected with care, as they significantly affect the circuit board’s smoothness.
5. Damage characteristics of electronic components on PCB circuit boards
6. Resistance damage
7. Resistors are the most numerous components in electrical equipment, though they are not the most frequently damaged. Open circuits are the most common type of resistor damage. An increase in resistance value is rare, and a decrease is even rarer. Common types include carbon film resistors, metal film resistors, wire wound resistors, and fuse resistors.
8. The first two types are the most widely used. Low resistance (below 100Ω) and high resistance (above 100kΩ) resistors are more likely to be damaged. Low-resistance resistors often burn and blacken, making them easier to detect, whereas high-resistance resistors are rarely damaged. Wire wound resistors, used for high current limiting, may burn, turn black, or crack, but some show no visible damage. Cement resistors, a type of wire wound resistor, might break when burned out. Fuse resistors may blow off a piece of skin from the surface but generally do not turn black. These characteristics help in quickly identifying damaged resistors.
9. Electrolytic capacitor damage
10. Electrolytic capacitors are common in electrical equipment and have a high failure rate. Damage can manifest as complete loss or reduction of capacity, mild to severe leakage, or a combination of both. Methods to identify damaged electrolytic capacitors include:
11. (1) Visual inspection: Damaged capacitors may leak, leaving oil on the circuit board or capacitor surface. These capacitors should be discarded. Some capacitors bulge when damaged and cannot be used.
12. (2) Touch: Capacitors with severe leakage may become hot and should be replaced.
13. (3) Electrolyte inside capacitors can dry out from prolonged heat, reducing capacitance. Capacitors near heat sinks and high-power components are more likely to be damaged.
14. Damaged semiconductor devices such as diodes and transistors
15. Diodes and transistors usually suffer from PN junction breakdown or open circuits, with short circuits being more common. There are two main damage types: one involves deteriorated thermal stability, causing issues after prolonged use; the other involves PN junction characteristics deteriorating, which might not be apparent with an R*1k multimeter setting but may show abnormal forward resistance at lower settings.
16. Testing transistors involves measuring forward and reverse resistance with a multimeter set to R*10 or R*1. If the forward resistance is within normal range and the reverse resistance is high, the PN junction is likely intact. Otherwise, further inspection is necessary. Note that peripheral resistance can affect readings on low-range settings.
17. Damaged integrated circuits
18. Integrated circuits have complex internal structures, making any part’s malfunction critical. Integrated circuits may suffer from complete damage or poor thermal stability. To diagnose complete damage, compare pin resistances with a functioning IC of the same model. For poor thermal stability, cooling the IC with absolute alcohol while it is operational can help determine if the failure persists or resolves. Typically, replacing the IC is necessary for a definitive diagnosis.
