Polycarbonate (PC) is a polymer containing a carbonate group in the molecular chain, which can be divided into aliphatic, aromatic, aliphatic-aromatic and other types according to the structure of the ester group.

The low mechanical properties of aliphatic and aliphatic-aromatic polycarbonates limit their application in engineering plastics. At present, only aromatic polycarbonate has been industrially produced. Due to the particularity of polycarbonate structure, it has become the fastest-growing general engineering plastic among the five major engineering plastics.

Strictly speaking, Seagate's personal computer hard drive, released in 1980, also uses polycarbonate, but it is more inclined to engineering plastics.

Li Yixuan's method side is different, although it belongs to polycarbonate, it is more inclined to plexiglass. In the manufacturing process, a certain amount of glass fiber material needs to be added to the polycarbonate base to make a hard disk base.

Hard disk platters made of this material can have a storage capacity of up to 20GB, which is enough to meet the development needs of personal computers in the next 20 years.

To tell the truth, this kind of disc material has not been popularized in history, it appeared too late, it only appeared in 2004, at this time the aluminum alloy disc has long been popularized, and its storage density is only 20GB on the line, therefore, it is a backward product as soon as it was born.

The reason why people discovered it was also stimulated by the glass hard drive launched by IBM in '98.

For another time and space, although this kind of disk-based material is backward, it is not lagging behind at such a point in time as 1978, which is a very advanced material.

Its physical and chemical properties are more stable and reliable than Seagate's engineering plastics, and it is more durable, less fragile, and its mechanical properties are much better than Seagate's engineering plastics. What's more, the material is a fraction of the cost of Seagate's disc base material, at one-fifth.

Li Yixuan gave this material a name, called acetate fiber glass plate. There is no other meaning, because it is made of polycarbonate + glass fiber mixture, and the molecular structure of the finished product is somewhat similar to the molecular structure of acetate, so it is named acetate fiber glass disc.

Polycarbonate is a petrochemical product and can also be extracted from coal, so polycarbonate materials are very common in the market and the material is very easy to obtain.

In addition, chemical products such as petrochemicals have a characteristic, that is, the larger the output, the lower the cost, and the smaller the output, the higher the cost. Therefore, Li Yixuan does not have to worry about Western countries getting stuck in his neck one day. Even if it's a real card, he can still get it from China.

Glass fiber does not need to worry, it can be produced in China, and it is how much it wants, and the quality of its products can fully meet the production needs of the plate base.

According to Li Yixuan's hard disk design requirements, it is necessary to establish two head plants, a reading head factory, a writing head factory, and a head bridge installation workshop, and the produced head needs to be installed on the bridge to form a reading and writing head group.

There is also a disc-based material processing plant and a magnetic material processing plant. Magnetic coating material is also the key raw material of the hard disk, it is directly related to how large the storage capacity of the hard disk can be, after many tests, Li Yixuan decided to use permalloy powder core, as the surface coating of the disc.

Permalloy powder core is not high-end at all, it can be produced in China and abroad, but it cannot be directly coated on the surface of the disc base, and it needs to be processed to process the magnetic powder to the nano level, and then use special industrial glue to coat the permalloy powder on the surface of the disc base.

Finally, there is the final assembly plant of hard disks. The shell of the hard disk is made of high-strength engineering plastics and aluminum alloy metal covers, which can be entrusted to third-party foundries like Foxconn.

In total, 5 factories need to be built. The total area of the hard disk production area designed by Li Yixuan is as high as 350,000 square meters, and the annual output of hard disks will be as high as 15 million after completion.

However, there is no need for such a large production capacity now, a production capacity of 100,000 pieces per year is completely enough, and it is necessary to slowly expand the plant and install new production lines in the future, but when the other party's production area is initially planned, the subsequent production capacity needs to be taken into account.

Li Yixuan's final plan is that the entire hard disk production area will eventually cover an area of 700,000 square meters, and the annual output of hard disks can reach more than 30 million per year. The 350,000 square meter production area can only be considered a medium-term plan.

The production of 3,000 hard drives is not high, you must know that in 2016 alone, Seagate's annual hard drive supply was as high as more than 60 million, and it is also the world's second largest hard drive supplier. In addition to the first place is Western Digital, the global annual supply of hard disks is close to 70 million.

Even Toshiba, which ranks outside the top 10 RB, has an annual supply of more than 30 million hard drives.

Li Yixuan spent a week to do a good job in the design and planning of the factory, and in Zhang Guifang's eyes, he questioned, "Son, I have no opinion on the medium-term plan with an annual output of 15 million hard disks and the long-term plan with an annual output of 30 million hard disks." But your initial annual production plan is 100,000 yuan, is this output too large? I'm afraid I won't be able to sell it then. ”

Li Yixuan took out a document from his briefcase, "Mom, this is Seagate's hard drive sales data in 1980. Seagate was founded in 1979 and released the company's first hard drive for personal computers the following year, with a size of 5.25 inches, a capacity of only 5MB, and a retail price of $599 in the market, which sold more than 33,000 units that year. ”

And my hard drive is much cheaper to produce than him due to the new thin-film sensing TFI head technology and disk-based material technology. I calculated, the production cost of a single hard disk is less than 50 US dollars, if the annual output of 100,000 units is calculated, the cost of each hard disk can be reduced to less than 40 US dollars, if it is an annual production of more than 500,000 units, the cost of hard disks can be reduced to less than 25 US dollars, if the annual output reaches more than 1 million, the cost can be controlled below 15 US dollars.

Seagate's hard drive capacity is only 5MB, and the platter speed is only 220-RPM Class; The read and write speed is only 2Kb/s, the cache chip capacity is not even 1Kb, the size is 5.25 inches larger, the retail unit price is 599 US dollars, and it can only sell more than 33,000 pieces a year.

Our hard drive is 3.5 inches, with a capacity of 10MB and a speed of 800-RPM Class; The read and write speed is 128Kb/s, and the cache chip capacity is 8K. We don't sell them as high, the international retail unit price is only 299 US dollars, so in comparison, can you sell 100,000 hard drives in a year? ”

In the end, Li Yixuan waved his hand in the air, and said confidently: "If we can't even sell 100,000 hard disks a year, what kind of business are we doing, let's close down and go back as soon as possible." ”