1. Design the schematic diagram based on the circuit’s function. The schematic design primarily considers the electrical characteristics of each component and organizes them according to their functional requirements. The diagram accurately reflects the critical functions of the PCB and the interrelationships between various components. This schematic design is the initial and crucial step in the PCB production process. Typically, software such as PROTEL is used for designing circuit schematics.
2. Once the schematic design is complete, each component must be packaged in PROTEL to create and standardize the grid with consistent appearance and size. After modifying the component package, go to Edit/Set Preferences/pin 1 to set the package reference point at the first pin. Then, execute Report/Component Rule Check to ensure all rules are verified, and confirm by selecting OK. At this point, the package is established.
3. Generate the PCB layout. After generating the netlist, position each component according to the dimensions of the PCB panel. During placement, ensure that no component leads cross each other. Once component placement is finished, perform a Design Rule Check (DRC) to correct any pin or lead crossing errors from component wiring. After resolving all errors, the PCB design process is complete.
4. Use special carbon paper to print the designed PCB diagram using an inkjet printer. Then, press the printed circuit diagram against the copper plate and place it on a heat press for hot transfer. The high temperature causes the ink on the circuit diagram to adhere to the copper plate.
5. Board Making. Prepare the solution by mixing sulfuric acid and hydrogen peroxide in a 3:1 ratio. Submerge the copper plate with ink stains into the solution and wait for about three to four minutes until the copper plate, excluding the ink stains, is fully corroded. Remove the copper plate and rinse it with clean water.
6. Punch Holes. Use a hole drill to create necessary holes in the copper plate. Afterward, insert each component’s pins into the holes from the back of the copper plate, and then solder the components in place using a welding tool.
7. Once soldering is complete, perform a comprehensive test of the circuit board. If issues arise during testing, identify the problem location using the schematic diagram from the initial design phase, and then re-solder or replace components as needed. The circuit board is considered complete once it passes all tests successfully.
How to Improve the Thermal Reliability of PCB Circuit Boards?
Under normal circumstances, the distribution of copper foil on a PCB circuit board is complex and difficult to model accurately. Thus, simplify the wiring shapes during modeling and use simplified models for electronic components close to the actual board, such as MOSFETs and integrated circuit blocks.
Thermal Analysis
Thermal analysis in SMD processing helps designers assess the electrical performance of PCB components and determine whether they or the circuit board might overheat. Simple thermal analysis calculates the average temperature, while more complex analyses require a transient model with multiple circuit boards. The accuracy of thermal analysis ultimately relies on the component power consumption data provided by the circuit board designer.
In many cases, weight and size are crucial. If the component’s actual power consumption is low, an overly conservative safety factor might lead to a design using inaccurate power consumption values. Conversely, if the thermal safety factor is too low, components may overheat beyond the analyst’s predictions, often necessitating heat sinks or fans, which increase cost and complexity. The addition of fans can also affect reliability, so active cooling methods are preferred over passive ones (e.g., natural convection, conduction, and radiation).
Simplified Modeling of Circuit Boards
Before modeling, identify key heating components like MOSFETs and integrated circuits, which convert most of their power loss into heat. These components should be carefully considered in the model.
Additionally, consider the copper foil on the circuit board substrate as a conductor of both electricity and heat. Although thin, copper’s high thermal conductivity (400 W/(m°C)) compared to the epoxy resin’s low thermal conductivity (0.276 W/(m°C)) makes it crucial in thermal modeling. Even thin copper foil has significant heat-guiding effects and should not be overlooked.
2. Once the schematic design is complete, each component must be packaged in PROTEL to create and standardize the grid with consistent appearance and size. After modifying the component package, go to Edit/Set Preferences/pin 1 to set the package reference point at the first pin. Then, execute Report/Component Rule Check to ensure all rules are verified, and confirm by selecting OK. At this point, the package is established.
3. Generate the PCB layout. After generating the netlist, position each component according to the dimensions of the PCB panel. During placement, ensure that no component leads cross each other. Once component placement is finished, perform a Design Rule Check (DRC) to correct any pin or lead crossing errors from component wiring. After resolving all errors, the PCB design process is complete.
4. Use special carbon paper to print the designed PCB diagram using an inkjet printer. Then, press the printed circuit diagram against the copper plate and place it on a heat press for hot transfer. The high temperature causes the ink on the circuit diagram to adhere to the copper plate.
5. Board Making. Prepare the solution by mixing sulfuric acid and hydrogen peroxide in a 3:1 ratio. Submerge the copper plate with ink stains into the solution and wait for about three to four minutes until the copper plate, excluding the ink stains, is fully corroded. Remove the copper plate and rinse it with clean water.
6. Punch Holes. Use a hole drill to create necessary holes in the copper plate. Afterward, insert each component’s pins into the holes from the back of the copper plate, and then solder the components in place using a welding tool.
7. Once soldering is complete, perform a comprehensive test of the circuit board. If issues arise during testing, identify the problem location using the schematic diagram from the initial design phase, and then re-solder or replace components as needed. The circuit board is considered complete once it passes all tests successfully.
How to Improve the Thermal Reliability of PCB Circuit Boards?
Under normal circumstances, the distribution of copper foil on a PCB circuit board is complex and difficult to model accurately. Thus, simplify the wiring shapes during modeling and use simplified models for electronic components close to the actual board, such as MOSFETs and integrated circuit blocks.
Thermal Analysis
Thermal analysis in SMD processing helps designers assess the electrical performance of PCB components and determine whether they or the circuit board might overheat. Simple thermal analysis calculates the average temperature, while more complex analyses require a transient model with multiple circuit boards. The accuracy of thermal analysis ultimately relies on the component power consumption data provided by the circuit board designer.
In many cases, weight and size are crucial. If the component’s actual power consumption is low, an overly conservative safety factor might lead to a design using inaccurate power consumption values. Conversely, if the thermal safety factor is too low, components may overheat beyond the analyst’s predictions, often necessitating heat sinks or fans, which increase cost and complexity. The addition of fans can also affect reliability, so active cooling methods are preferred over passive ones (e.g., natural convection, conduction, and radiation).
Simplified Modeling of Circuit Boards
Before modeling, identify key heating components like MOSFETs and integrated circuits, which convert most of their power loss into heat. These components should be carefully considered in the model.
Additionally, consider the copper foil on the circuit board substrate as a conductor of both electricity and heat. Although thin, copper’s high thermal conductivity (400 W/(m°C)) compared to the epoxy resin’s low thermal conductivity (0.276 W/(m°C)) makes it crucial in thermal modeling. Even thin copper foil has significant heat-guiding effects and should not be overlooked.
