The process is generally as follows:
1. Open material
Cut the purchased copper sheets, which come in rolls, into smaller sheets of various sizes, similar to cutting paper.
2. Internal printing
Print the inner layer of the circuit board onto the cut copper sheets, establishing the PCB’s internal circuitry.
3. Pressing
Following the previous step, an inner circuit board is created. To safeguard this circuit, a layer of material is pressed onto the front and back to prevent damage. The name of the material escapes me.
4. Drilling
When we open the case, we notice numerous electronic components on the computer motherboard. These components require holes for attachment to the board. This involves drilling holes in the board, similar to how road repair workers use machines to drill into the ground. The holes serve the same purpose. Depending on the wear of the punching machine’s needles, the company incurs annual costs for replacing the damaged needles.
5PTH
Copper (Cu) is utilized in the holes, providing significant advantages. Newly punched holes may be compromised during subsequent processes. Copper offers a relatively high load-bearing capacity, helping to protect these holes. Why not use other materials? The answer is complex and cannot be summarized in a single statement; there is a process involving zinc plating that plays a role here.
6 Outside Lines
Finally, the printing of the outer circuit board can commence.
7 Plating
A layer of tin is applied and then etched. I can’t recall the specific details.
8 Half Test
The testing of semi-finished products begins here. If any issues arise with the internal wiring, they must be promptly addressed. Some clients stipulate that repairs are not permitted and that faulty boards should be scrapped directly. Once scrapped, the copper material on the board can be recycled through chemical extraction.
9 Solder Mask
10 Spray Tin
11 Text
Text is engraved on the board according to customer specifications. In modern manufacturing, OEM production is quite common, typically involving printing the required text with ink on the board and then curing it in a high-temperature oven.
12 Molding
13% Finished Product Test
14% Finished Product Inspection
15 Packs
16 Lending
The production of PCB boards follows an assembly line model. The cutting process can be tightly controlled, but monitoring during the intermediate stages is more challenging. After extensive effort, it becomes nearly impossible to identify the original form of the copper piece. Work in Progress (WIP) can be closely monitored at each stage, allowing us to determine whether timely delivery is feasible. The output of PCB boards is measured in square feet, not by quantity.
The WIP control method is known as CheckPoint. For instance, a checkpoint can be established at process 8 to assess how many qualified products have been produced so far. If any irregularities are detected, an investigation into the cause should be initiated, and necessary materials should be replenished promptly to maintain production.
Adding some fundamental knowledge, the significance of PCBs:
PCBs are foundational components in the information and electronics industry, categorized within the electronic component sector. Based on the number of layers, PCBs are classified into single-sided boards (SSB), double-sided boards (DSB), and multi-layer boards (MLB). In terms of flexibility, PCBs are categorized as rigid printed circuit boards (RPC) and flexible printed circuit boards (FPC). The PCB industry is further divided into six major segments: single-sided, double-sided, conventional multilayer, flexible, HDI (high-density interconnect) boards, and package substrates, following the basic classifications mentioned above.
