Focusing on the birth of the most vital component of the phone: the motherboard, we have been able to follow its creation step by step. From a simple empty plate to becoming the complete brain that gives life to each device. A fascinating mix of extreme heat, robotic precision, laser scans and a level of protection that seems straight out of a science fiction movie. This was all we saw in the ‘heart’ of Oppo.
The beginning: optical inspection and assembly
The process begins when the motherboards undergo an automated optical inspection (AOI). The guide who gave us the tour explained that in the past, they had to move some components because the light on the original inspection machine couldn’t scan them properly. After this verification, the board advances to a chip assembly machine, which positions the tiny components with robotic precision.
Precision soldering: the nitrogen reflow oven
Once the components are assembled, the board enters a “BTU nitrogen reflow oven.” This machine is essential. The guide described how the board goes through four controlled temperature zones: preheat, activation, reflux, and cool down.
The goal is to melt the solder paste. As the temperature increases, the paste melts and, as it cools, creates the solder joints that permanently connect the components to the board.
The use of nitrogen is deliberate. The guidance was emphatic: “at very high temperatures, oxygen could cause some damage to electrical products.” Nitrogen, being “much more stable,” is crucial “for the quality of the product.”
Quality control at 245°C
Maintaining the exact temperature inside the oven, which reaches peaks of 245 degrees, is vital. To ensure this, the facility does not skimp on controls. “We have over twelve different temperature sensors inside this oven,” the guide noted.
If any section deviates from the “stable range,” the sensors will send the message and an alert to managers. This allows the monitoring team to see what is happening inside the oven and make immediate corrections.
The global brain: a connected control center
One of the most revealing aspects of the visit was the factory control center. This room not only manages the lines of this plant Oppo in Dongguan, but “helps manage all these different lines, not just in this factory, but around the world.”
A system of colored lights informs the status of each production line:
- Green Light: “It means everything is working fine.”
- Yellow Light: Indicates “waiting for materials”.
- Red light: “It means something bad has happened.”
A “red light” incident can be anything from “missing material” to a “stuck robotic arm.” When it occurs, it will “send the message to the control center” and the center will mobilize personnel to solve the problem.
Total traceability and the power of the barcode
After the welding process, the guide highlighted the importance of barcodes. Every motherboard and “some important components” have one.
These codes are the key to a complete record of information. “By scanning the barcode, we can help record all the information,” he explained. This includes “on what production line it was manufactured, at what time, what type of material was used and from what supplier.”
This database is a fundamental quality tool. “In case something bad has happened, it’s very easy for us to trace back and see what went wrong with this product.”
Inspection, replay and hidden layers
The work on the motherboard does not end in the first oven. It goes through another inspection machine that specifically looks for defects like solder bridges or missing solder.
From hardware to software: giving “life” to the board
Once the board hardware is finished, the guide offered a clear analogy: the board is like a “newborn baby,” but it is “empty in its head.”
The next stage is downloading the software. It is at this point where we add a lot of information and all the essential software is downloaded to the hard drive, from the ColorOS operating system to the preloaded applications that the end user will find when turning on their phone.
Rigorous calibration and testing
With the software installed, the board enters an intensive testing phase. First, the calibration of the radio frequency values. The guide highlighted that “Oppo has set strict requirements compared to our national requirements.”
Once the values are calibrated, they are recorded on the mobile and it goes through a comprehensive test, followed by Wi-Fi and Bluetooth tests and finally an electricity test to ensure that each function of the motherboard worked well under current.
Extreme protection: motherboard shielding
Since the motherboard is the most important component, its protection is a priority. The guide contextualized its importance: “around 2000, the biggest problem that could happen to a mobile phone was the motherboard” due to drops or water. “Nowadays,” he continued, “the biggest problem may be the screen,” precisely because the motherboard is now excellently protected.
This protection is achieved by adding many accessories and applying glue on the surface of the motherboard. This glue has a double function: it helps to solidify the components and, on the other hand, it also has the function of being waterproof.
This technology is what allows some series of our mobile phones to be taken to the shower, swimming or diving. Additionally, copper sheets and silicone waterproof coatings are added, all as part of the protection work.
Production, human factor and final tests
The plant’s production figures are notable. The floor visited houses several production lines, and “each production line can produce around 2 thousand to 3 thousand” motherboards “in one day.”
Regarding personnel, the number varies. For the Reno series, between 30 and 50 people are needed on a single line, while other high-end series may require fewer staff and other ranges more.
Finally, even after passing basic tests (such as the 5G signal test), the phones do not go to market. They must go through the “Reliability Lab”. In the words of the guide, this is where the devices “fight” against different stress tests that range from blows to other types of attacks that the cell phone could suffer to guarantee that resistance that the brand boasts so much about. Only after passing them are they allowed to be launched on the market.