1. Screen Printing Method:
The circuit board is commonly referred to as a “printed circuit board” (abbreviated as PCB), derived from its “screen printing” technique. The basic steps involved are:
Design layout – tracing – exposure of the board (creating the screen printing master) – printing – chemical etching – cleaning and surface treatment – applying soldering, markings, solder mask, and other layers – mechanical processing such as cutting and punching – finalizing the circuit board.
This method encompasses numerous production steps and a complex workflow. It is primarily utilized in the mass production of PCBs and is seldom employed in laboratory settings.
2. Engraving Method:
The engraving method is executed using a specialized engraving machine, where the actual electrical connections are established after the excess copper foil on the copper substrate is removed through mechanical milling. This technique offers high precision, but it operates at a slow processing speed and incurs relatively high costs.
3. Freehand method
Utilize a pen or a pen-like tool to apply anti-corrosion paint directly onto the copper-clad laminate, followed by chemical etching and other processes. Given that today’s electronic components are compact, with pin spacings often in the millimeter range and narrow copper traces, drawing by hand has become increasingly challenging.
4. Layout method
Electronics stores offer “standard pre-cut symbols and tape.” You can select the appropriate symbols (primarily pads) and tape based on your circuit design, then adhere them to the copper foil surface of the laminate. Use a softer hammer, like one made of smooth rubber or plastic, to ensure full adhesion of the stickers to the copper foil, paying special attention to the bends and overlaps in the traces. If needed, a heater can be employed to enhance adhesion. Once affixed, the board can be etched.
5. Use of pre-coated photosensitive copper clad laminate
A special type of copper clad laminate features a pre-coated layer of photosensitive adhesive on its copper foil surface, commonly referred to as “pre-coated photosensitive copper clad laminate” or “photosensitive board.” The production method is as follows: Print the PCB design from your computer as a black-and-white image at a 1:1 ratio. Take a photosensitive board matching the drawing size and remove the protective film. Press the drawing against the photosensitive PCB using a glass or clear plastic plate. After exposing it to ultraviolet light for 1-5 minutes, develop the board using a solution of developer mixed with water at a ratio of 1:20. Once the unnecessary copper coating is fully exposed, rinse with water before etching with ferric chloride. With practice, trace accuracy can reach 0.1mm. Currently, the market price for “pre-coated photosensitive copper clad sheets” remains relatively high.
6. Thermal transfer method
Graphics for printed circuit boards are printed onto specialized thermal transfer paper processed by a laser printer. The “toner” consists of black plastic particles with magnetic properties. The thermal transfer paper is then placed over the copper-clad board and sent through the plate-making apparatus. This machine operates on a heat transfer principle, utilizing two specially designed high-temperature silicone rollers as a transmission mechanism. Two infrared quartz heating tubes uniformly heat the rollers to 180.5 degrees Celsius, while the surface of the rollers can withstand temperatures up to 300 degrees Celsius. The rollers are driven by a synchronous motor, maintaining low and constant speed. As the thermal transfer paper and copper-clad board pass between these heated rollers, the toner melts. The thermal transfer paper, treated with several layers of special coatings, exhibits high temperature resistance and non-stick properties. At 180.5 degrees Celsius, the adhesion of the thermal transfer paper to the melted toner significantly diminishes, allowing the melted toner to bond to the copper-clad board under pressure. Once cooled, a solid print is formed. The toner thus creates a protective layer on the copper-clad board, exhibiting good corrosion resistance against corrosive solutions like FeCl3. This process results in a finely crafted printed circuit board.
The circuit board is commonly referred to as a “printed circuit board” (abbreviated as PCB), derived from its “screen printing” technique. The basic steps involved are:
Design layout – tracing – exposure of the board (creating the screen printing master) – printing – chemical etching – cleaning and surface treatment – applying soldering, markings, solder mask, and other layers – mechanical processing such as cutting and punching – finalizing the circuit board.
This method encompasses numerous production steps and a complex workflow. It is primarily utilized in the mass production of PCBs and is seldom employed in laboratory settings.
2. Engraving Method:
The engraving method is executed using a specialized engraving machine, where the actual electrical connections are established after the excess copper foil on the copper substrate is removed through mechanical milling. This technique offers high precision, but it operates at a slow processing speed and incurs relatively high costs.
3. Freehand method
Utilize a pen or a pen-like tool to apply anti-corrosion paint directly onto the copper-clad laminate, followed by chemical etching and other processes. Given that today’s electronic components are compact, with pin spacings often in the millimeter range and narrow copper traces, drawing by hand has become increasingly challenging.
4. Layout method
Electronics stores offer “standard pre-cut symbols and tape.” You can select the appropriate symbols (primarily pads) and tape based on your circuit design, then adhere them to the copper foil surface of the laminate. Use a softer hammer, like one made of smooth rubber or plastic, to ensure full adhesion of the stickers to the copper foil, paying special attention to the bends and overlaps in the traces. If needed, a heater can be employed to enhance adhesion. Once affixed, the board can be etched.
5. Use of pre-coated photosensitive copper clad laminate
A special type of copper clad laminate features a pre-coated layer of photosensitive adhesive on its copper foil surface, commonly referred to as “pre-coated photosensitive copper clad laminate” or “photosensitive board.” The production method is as follows: Print the PCB design from your computer as a black-and-white image at a 1:1 ratio. Take a photosensitive board matching the drawing size and remove the protective film. Press the drawing against the photosensitive PCB using a glass or clear plastic plate. After exposing it to ultraviolet light for 1-5 minutes, develop the board using a solution of developer mixed with water at a ratio of 1:20. Once the unnecessary copper coating is fully exposed, rinse with water before etching with ferric chloride. With practice, trace accuracy can reach 0.1mm. Currently, the market price for “pre-coated photosensitive copper clad sheets” remains relatively high.
6. Thermal transfer method
Graphics for printed circuit boards are printed onto specialized thermal transfer paper processed by a laser printer. The “toner” consists of black plastic particles with magnetic properties. The thermal transfer paper is then placed over the copper-clad board and sent through the plate-making apparatus. This machine operates on a heat transfer principle, utilizing two specially designed high-temperature silicone rollers as a transmission mechanism. Two infrared quartz heating tubes uniformly heat the rollers to 180.5 degrees Celsius, while the surface of the rollers can withstand temperatures up to 300 degrees Celsius. The rollers are driven by a synchronous motor, maintaining low and constant speed. As the thermal transfer paper and copper-clad board pass between these heated rollers, the toner melts. The thermal transfer paper, treated with several layers of special coatings, exhibits high temperature resistance and non-stick properties. At 180.5 degrees Celsius, the adhesion of the thermal transfer paper to the melted toner significantly diminishes, allowing the melted toner to bond to the copper-clad board under pressure. Once cooled, a solid print is formed. The toner thus creates a protective layer on the copper-clad board, exhibiting good corrosion resistance against corrosive solutions like FeCl3. This process results in a finely crafted printed circuit board.
