Factory Tour in China - How PCB Is Made | PCBWay

Summary

In this video, the process of PCB manufacturing and assembly at PCBWay factory is explored in detail. The journey begins with raw 2-layer PCB material, which is cut, drilled, and plated with copper. The boards undergo a series of chemical and electroplating steps to prepare for component placement. After applying a photosensitive layer and solder mask, the boards are tested and inspected for quality. The final steps include soldering components, inspecting for defects, and packaging for shipment. The video offers a comprehensive look at PCB production and the technology behind modern electronics manufacturing.

Takeaways

• 😀 The process of PCB manufacturing starts with large 2-layer raw materials, which are cut down to size and shaped into panels.
• 😀 Drilling is a critical step, with a drill file providing precise locations for holes that are drilled into the panels.
• 😀 Electroless copper plating is used to add copper to the drilled holes, creating electrical connections between layers of the PCB.
• 😀 The PCB panels are cleaned to remove chemicals before applying a photosensitive foil, which is essential for creating tracks on the board.
• 😀 After the photosensitive foil is applied, a UV light process projects the PCB layout, creating copper tracks on the material.
• 😀 Electroplating adds copper to the vias, while a subsequent tin bath coats the copper to protect it during further processing.
• 😀 The photosensitive layer is removed in a chemical process, leaving behind the copper tracks that form the PCB's electrical pathways.
• 😀 Solder mask, often green, is applied to the PCB to protect and insulate non-soldered areas, with precise removal over the pads.
• 😀 After the solder mask, a silkscreen process applies white markings (often text and symbols) on the PCB for component identification.
• 😀 Final testing is conducted to check for electrical continuity and proper connections, ensuring no shorts or broken lines.
• 😀 Once the board assembly is completed, it is inspected, cleaned, and packaged before being shipped to the customer.

Q & A

What is the raw material used to begin the PCB manufacturing process?

The raw material used at the beginning is a large 2-layer PCB, which has copper on both the top and bottom layers with isolation in between.

Why do the panels need to be cut down in size?

The panels need to be cut down to a specific size because the machines in the factory work with panels of a particular size.

Why is it important to round the corners of the panels?

Rounding the corners is important to make the panels safer to manipulate during the manufacturing process.

What is the purpose of drilling the PCB panels?

Drilling is necessary to create holes in the PCB, and the design file (drill file) specifies the exact position and size of the holes.

What is the process of electroless copper plating and why is it done?

Electroless copper plating is a chemical process used to deposit copper inside the drilled holes, making the top and bottom layers of the PCB electrically connected.

What is the difference between electroless plating and electroplating?

Electroless plating is slower and more expensive but is necessary for applying copper to non-conductive surfaces. Electroplating is faster and cheaper, used after electroless plating to grow the copper layer.

Why is cleaning the PCB an essential step?

Cleaning is necessary to remove chemicals and contaminants from the PCB's surface and holes, ensuring that the next process, such as applying photosensitive foil, is done properly.

What is the role of the photosensitive foil applied to the PCB?

The photosensitive foil is applied to the PCB to help in the creation of the copper tracks, which will form the circuit layout.

How does the PCB design get transferred onto the photosensitive layer?

The design is projected onto the photosensitive layer using a specialized machine that transfers the PCB tracks and layout onto the material.

What is the function of the solder mask on the PCB?

The solder mask, typically green in color, is applied to protect areas of the PCB from unwanted soldering. It is later removed from the areas where components will be soldered, known as pads.

Why is the PCB tested after the assembly process?

The PCB is tested to ensure that all components are correctly placed and soldered, and to detect any issues like short circuits or disconnected tracks.

What is the process for handling multilayer PCBs during manufacturing?

Multilayer PCBs require additional materials like prepreg (an insulating layer) and copper. The layers are stacked together and baked in an oven to bond them into a solid multilayer board.

How are components soldered onto the PCB during the assembly process?

The solder paste is applied to the pads where components will be placed. Then, an assembly machine places the components onto the board, which is heated in an oven to melt the solder and fix the components in place.

What is the purpose of the wave soldering process for through-hole components?

The wave soldering process involves applying flux to the board and then passing it through a tin wave, which melts the solder and secures the through-hole components to the PCB.

How is the final inspection of the PCB carried out?

The final inspection includes testing the board for any issues, such as misplaced or poorly soldered components. If everything checks out, the board is cleaned, packed, and ready for shipment.