The Process of PCB Manufacturing
Depending on the design, the pcb manufacturing process takes multiple steps to complete. These steps include: design, fabrication and testing.
The first stop for a PCB is the fab or board house. This is where the materials for the bare board stackup are bound together.
Next, the laminate panels receive photo-reactive chemicals and are exposed to ultraviolet light. This light hardens the photoresist that covers the copper layer of the bare board.
The design process for a PCB involves a logical workflow implemented in specialized CAD software. The result is a set of files that can be used to fabricate and assemble pcb manufacturing the circuit board. This process generates a wealth of data and allows the designer to ensure that the final product meets their functional and performance requirements. In addition, the designer must work alongside mechanical designers to ensure that the physical form and fit of the device is a good match for its function.
The first step of the manufacturing process is to print the PCB design onto a piece of laminate material. This is followed by copper being pre-bonded to the laminate, which assists in its structure. Then, a photosensitive chemical called photo resist is printed over the top of the copper foil layer. This enables technicians to see the blueprints underneath. Then, the machine can automatically compare the digital image to the original Gerber file and alert the technician of any issues.
PCB manufacturers who specialize in quick-turn projects use a variety of advanced automated processes to reduce turnaround times and deliver the best quality. They also offer a range of materials to suit different applications. Businesses can choose from a wide range of FR-4, aluminum, Rogers and HDI options to create a custom PCB that suits their needs. Moreover, online PCB manufacturers can provide technical support services to their clients.
Once the PCB design is complete, it’s forwarded to a manufacturing shop or “fab house.” The fab house will conduct a check called a Design for Manufacture (DFM) to make sure the blueprint meets the minimum tolerances required during fabrication.
Once a DFM check is complete, the fab house will use a special printer known as a plotter to make a photo film of the PCB’s inner layers and outer layer. This will allow them to print the pattern on a blank copper-clad board. Then, the outer layer is covered with a layer of photoresist material. Then, the outer layer is exposed to UV light. The UV exposure hardens the photoresist, leaving only the bare copper on the inner layers. This will be plated later on.
After the inner layers are printed, they’re etched. This removes the non-essential copper and exposes the black ink that shows the conductive paths. Finally, the etching process is repeated for the outer layer.
Depending on the design, a legend may be printed on the outer layers. This is helpful for identifying components, switch settings, and test points. Originally, this was done with silkscreen printing epoxy ink, but now it’s more common to use liquid photo imaging or another type of printing method. Then the board is ready for assembly. You can choose to mount components on it using through-hole technology or surface mount technology.
Testing PCBs is a crucial step in the manufacturing process. It ensures that the components are functioning properly and follows the original blueprint design. In addition, it helps reduce production costs and prevents product defects. Testing consists of various methods and tools to examine the functionality, quality, and features of the final product. These tests include flying probe, In-Circuit Test (ICT), and bed of nails tester.
Before the etching stage, the panel is coated with photo resist. This is a type of film that can be imaged by special printers. The manufacturer then uses a powerful chemical to eat away at the copper that isn’t covered by the resist. Once the etching is complete, the technician inspects the finished board to ensure that it meets the specifications of the blueprint.
Functional testing is another common method for ensuring that the board PCB Manufacturing Supplier is functioning properly. It simulates the environment in which the board will be used and is best at detecting errors in component values. It is also cheaper than other types of testing.
Other types of testing for PCBs include ionic contamination tests and micro-section analysis. These tests help detect ionic residues that can degrade the circuit boards, and they are essential in ensuring that a final product has a high quality and performance. They are a part of the DFM (Design for Manufacture) process and should be implemented in the initial stages of the design process.
After all the effort that goes into designing a PCB and having it made, the last thing you want to see is it damaged during shipment. That’s why reputable PCB manufacturers use proper packaging that protects the boards from ESD damage and moisture penetration. This type of packaging is called static shielding. It is usually pink poly bubble wrap and it’s a good idea to ask about this before placing your order.
A key step in the PCB manufacturing process is imaging the inner layer. Unlike architectural blueprints, which print out on an 8.5 x 11 sheet of paper, PCB plans are printed with a special plotter printer that develops a film. Technicians also print out the solder mask for the inner layer using a different color film. Then, a machine creates registration holes in the two films so that they line up properly when adding copper to the laminate material later.
The next stage is etching. After the photo resist is removed, a powerful chemical is used to eat away at the copper that isn’t covered by the hardened photo resist. Once the unwanted copper is gone, technicians add the solder mask and apply the copper paste to each layer. They then place the inner layer onto the laminate material, lining up the registration holes with those in the outer layers.