Some people new to the electronics manufacturing industry may not fully understand PCBA and PCB and might confuse the two. When I first entered the electronics field, I faced this issue as well. To help everyone differentiate between them and avoid unnecessary confusion, the following editor will explain the difference between PCB and PCBA.
Quickly Recognize the Difference Between PCBA and PCB
1. Recognize the PCB
PCB has several names, including circuit board, printed circuit board, etc. It is a crucial electronic component used to support and connect electronic components.
2. Recognize PCBA
PCBA stands for Printed Circuit Board Assembly. In English, it is commonly referred to as PCB Assembly. It refers to the completed product formed through processes such as SMT patch, DIP plug-in, and testing of an empty PCB board.
3. The Difference Between PCBA and PCB
PCB is an empty board with no components on its surface, while PCBA is a processed PCB with resistors, capacitors, chips, and other components installed to create a board with specific functions. The core components of all electronic products are made up of PCBA.
4. Core Board Punching and Inspection
Once the core board is successfully produced, alignment holes are punched to facilitate alignment with other materials. Since modifications cannot be made once the core board is pressed with other PCB layers, inspection is crucial. The machine will automatically compare the board with the PCB layout drawing to check for errors.
5. Laminating
A new raw material called prepreg is required here. It serves as the adhesive between the core board and other PCB layers (if there are more than four), as well as between the core board and the outer copper foil. Additionally, it provides insulation. The lower copper foil and two layers of prepreg are fixed in advance using the alignment hole and the lower iron plate. The finished core board is then placed in the alignment hole. Finally, two layers of prepreg, a layer of copper foil, and a layer of pressure-bearing aluminum plate are added on top of the core plate. The PCB boards, clamped by the iron plates, are placed on the support and sent to the vacuum heat press for laminating. The high temperature in the vacuum heat press melts the epoxy resin in the prepreg, bonding the core boards and copper foils together under pressure. After lamination, remove the upper iron plate and then the pressure-bearing aluminum plate. The aluminum plate isolates different PCBs and ensures the smoothness of the outer copper foil. The PCB surfaces now have a layer of smooth copper foil.
6. Drilling
To connect the four layers of non-contact copper foils in the PCB, first drill through the through holes to open the PCB and then metalize the hole walls to ensure conductivity. Use the X-ray drilling machine to locate the inner core board. The machine automatically finds and locates the hole on the core board, then punches a positioning hole on the PCB to ensure accurate drilling from the hole’s center. Place a layer of aluminum plate on the punching machine, then position the PCB on top. For efficiency, stack 1 to 3 identical PCBs for perforation. Cover the top PCB with another layer of aluminum plate. The aluminum plates prevent tearing of the copper foil during drilling. In the previous lamination process, excess molten epoxy was squeezed out, requiring trimming. A profiling milling machine cuts the PCB’s periphery according to its XY coordinates.
7. Copper Chemical Precipitation on the Hole Wall
Since almost all PCB designs use perforations to connect different layers, a good connection requires a 25-micron copper film on the hole wall. This thickness is achieved by electroplating, but the hole wall consists of non-conductive epoxy resin and glass fiber. The first step is to deposit a conductive material on the hole wall and form a 1-micron copper film on the entire PCB surface, including the hole wall, through chemical deposition. The entire process, including chemical treatment and cleaning, is controlled by a machine. Fixed PCB. Cleaning the PCB. Shipping PCB.
8. Outer PCB Layout Transfer
Next, transfer the outer layer PCB layout to the copper foil. This process is similar to the transfer of the inner core board’s PCB layout. The layout is transferred to the copper foil using photocopying and photosensitive films. The key difference is that positive films are used for the outer layer. For the internal PCB layout, a subtractive method and negative films are used. The PCB is covered by the cured photosensitive film as a circuit, and uncured photosensitive film is cleaned away. After etching the exposed copper foil, the PCB layout circuit is protected by the cured photosensitive film. For the outer PCB layout, a positive film is used. The non-circuit areas are covered with cured photosensitive film, while uncured film is cleaned off. Electroplating is then performed, with copper plated first and tin added afterward where no film is present. After removing the film, alkaline etching is carried out, followed by tin removal. The circuit pattern remains because it is protected by tin. Clamp the PCB and electroplate copper. As previously noted, to ensure sufficient conductivity in the holes, the copper film on the hole walls must be 25 microns thick. This process is automatically controlled by a computer to ensure accuracy.
9. Outer PCB Etching
An automated assembly line completes the etching process. First, clean the cured photosensitive film from the PCB. Then use a strong alkali to remove any unnecessary copper foil. Next, use a tin-stripping solution to remove the tin plating from the PCB layout copper foil. After cleaning, the 4-layer PCB layout is complete.
Quickly Recognize the Difference Between PCBA and PCB
1. Recognize the PCB
PCB has several names, including circuit board, printed circuit board, etc. It is a crucial electronic component used to support and connect electronic components.
2. Recognize PCBA
PCBA stands for Printed Circuit Board Assembly. In English, it is commonly referred to as PCB Assembly. It refers to the completed product formed through processes such as SMT patch, DIP plug-in, and testing of an empty PCB board.
3. The Difference Between PCBA and PCB
PCB is an empty board with no components on its surface, while PCBA is a processed PCB with resistors, capacitors, chips, and other components installed to create a board with specific functions. The core components of all electronic products are made up of PCBA.
4. Core Board Punching and Inspection
Once the core board is successfully produced, alignment holes are punched to facilitate alignment with other materials. Since modifications cannot be made once the core board is pressed with other PCB layers, inspection is crucial. The machine will automatically compare the board with the PCB layout drawing to check for errors.
5. Laminating
A new raw material called prepreg is required here. It serves as the adhesive between the core board and other PCB layers (if there are more than four), as well as between the core board and the outer copper foil. Additionally, it provides insulation. The lower copper foil and two layers of prepreg are fixed in advance using the alignment hole and the lower iron plate. The finished core board is then placed in the alignment hole. Finally, two layers of prepreg, a layer of copper foil, and a layer of pressure-bearing aluminum plate are added on top of the core plate. The PCB boards, clamped by the iron plates, are placed on the support and sent to the vacuum heat press for laminating. The high temperature in the vacuum heat press melts the epoxy resin in the prepreg, bonding the core boards and copper foils together under pressure. After lamination, remove the upper iron plate and then the pressure-bearing aluminum plate. The aluminum plate isolates different PCBs and ensures the smoothness of the outer copper foil. The PCB surfaces now have a layer of smooth copper foil.
6. Drilling
To connect the four layers of non-contact copper foils in the PCB, first drill through the through holes to open the PCB and then metalize the hole walls to ensure conductivity. Use the X-ray drilling machine to locate the inner core board. The machine automatically finds and locates the hole on the core board, then punches a positioning hole on the PCB to ensure accurate drilling from the hole’s center. Place a layer of aluminum plate on the punching machine, then position the PCB on top. For efficiency, stack 1 to 3 identical PCBs for perforation. Cover the top PCB with another layer of aluminum plate. The aluminum plates prevent tearing of the copper foil during drilling. In the previous lamination process, excess molten epoxy was squeezed out, requiring trimming. A profiling milling machine cuts the PCB’s periphery according to its XY coordinates.
7. Copper Chemical Precipitation on the Hole Wall
Since almost all PCB designs use perforations to connect different layers, a good connection requires a 25-micron copper film on the hole wall. This thickness is achieved by electroplating, but the hole wall consists of non-conductive epoxy resin and glass fiber. The first step is to deposit a conductive material on the hole wall and form a 1-micron copper film on the entire PCB surface, including the hole wall, through chemical deposition. The entire process, including chemical treatment and cleaning, is controlled by a machine. Fixed PCB. Cleaning the PCB. Shipping PCB.
8. Outer PCB Layout Transfer
Next, transfer the outer layer PCB layout to the copper foil. This process is similar to the transfer of the inner core board’s PCB layout. The layout is transferred to the copper foil using photocopying and photosensitive films. The key difference is that positive films are used for the outer layer. For the internal PCB layout, a subtractive method and negative films are used. The PCB is covered by the cured photosensitive film as a circuit, and uncured photosensitive film is cleaned away. After etching the exposed copper foil, the PCB layout circuit is protected by the cured photosensitive film. For the outer PCB layout, a positive film is used. The non-circuit areas are covered with cured photosensitive film, while uncured film is cleaned off. Electroplating is then performed, with copper plated first and tin added afterward where no film is present. After removing the film, alkaline etching is carried out, followed by tin removal. The circuit pattern remains because it is protected by tin. Clamp the PCB and electroplate copper. As previously noted, to ensure sufficient conductivity in the holes, the copper film on the hole walls must be 25 microns thick. This process is automatically controlled by a computer to ensure accuracy.
9. Outer PCB Etching
An automated assembly line completes the etching process. First, clean the cured photosensitive film from the PCB. Then use a strong alkali to remove any unnecessary copper foil. Next, use a tin-stripping solution to remove the tin plating from the PCB layout copper foil. After cleaning, the 4-layer PCB layout is complete.
