(1) alloy shell
1, Al-Mg alloy
Al-Mg alloy is mainly composed of aluminum, and a small amount of magnesium or other metal materials is added to strengthen its hardness. Because it is metal, its thermal conductivity and strength are particularly outstanding. Al-Mg alloy has light hardness, low density, good heat dissipation and strong compression resistance, which can fully meet the requirements of 3C products for high integration, thinness, miniaturization, anti-collision and electromagnetic shielding heat dissipation. Its hardness is several times that of the traditional plastic case, but its weight is only one third of the latter, and it is usually used for the case of middle and high-grade ultra-thin or small-sized notebooks.
Moreover, the silver magnesium-aluminum alloy shell can make the product more luxurious and beautiful and easy to color. Through the surface treatment process, it can be turned into personalized powder blue powder, which adds a lot of color to notebook computers, which is incomparable to engineering plastics and carbon fiber. Therefore, Al-Mg alloy has become the preferred shell material for portable notebook computers. At present, most manufacturers have applied aluminum-magnesium alloy shell technology to notebook computer products.
2. Titanium alloy
Although Al-Mg-Au alloy is good, it also has many disadvantages. In order to overcome the shortage of Al-Mg-Au material, IBM engineers applied a more effective material-carbon fiber reinforced titanium composite to notebook computers.
Titanium is an expensive metal, much more expensive than magnesium. In the past, it was mainly used in special occasions requiring high strength and low weight applications, such as aerospace components, aircraft manufacturing and medical devices.
Excellent impact resistance makes it a perfect choice for sports equipment such as racing car shells and golf clubs. Titanium alloy can be said to be a reinforced version of aluminum-magnesium alloy, which is superior to aluminum-magnesium alloy in heat dissipation, strength and surface texture, and has better machinability and more complex and changeable appearance than aluminum-magnesium alloy. Its key breakthrough is stronger and thinner.
In terms of strength and toughness, titanium alloy is three to four times that of magnesium alloy. The higher the toughness, the greater the pressure it can withstand, and the more it can support large-size displays. Therefore, even if the titanium alloy model is equipped with a 15-inch display screen, there is no need to reserve a too wide border around the panel. As for the thinness, the thickness of titanium alloy is only 0.5mm, which is half that of magnesium alloy. Halving the thickness can make the laptop more petite. This is also the special material for many books of IBM in recent years, which has not been seen in other books.
The only disadvantage of titanium alloy is that it needs complicated processing procedures such as welding to make a notebook computer case with complicated structure. These production processes generate considerable costs, so they are very expensive. At present, titanium composite materials such as titanium alloy are still IBM's special materials, which is one of the reasons why IBM notebook computers are more expensive.
(2), plastic shell
1, carbon fiber
Carbon fiber material is a very interesting material, which has both elegant and strong characteristics of aluminum-magnesium alloy and high plasticity of ABS engineering plastics. Its appearance is similar to that of plastic, but its strength and thermal conductivity are better than that of ordinary ABS plastic, and carbon fiber is a conductive material, which can play a shielding role similar to metal (ABS shell needs to be shielded by another metal film).
Therefore, as early as June 65438+April 0998, IBM took the lead in launching a notebook computer with a carbon fiber shell, which is also the protagonist that IBM has been vigorously promoting. According to IBM's data, the strength and toughness of carbon fiber are twice that of aluminum-magnesium alloy, and the heat dissipation effect is the best. If used at the same time, the carbon fiber type shell is the least hot to the touch.
The disadvantage of carbon fiber is high cost, and it is not easy to form without ABS shell, so the shape of carbon fiber shell is generally simple and lacks change, and it is also difficult to color. In addition, the carbon fiber shell has a disadvantage, that is, if the grounding is not good, there will be a slight leakage inductance, so IBM covers its carbon fiber shell with an insulating coating.
2.PC-GF-## (polycarbonate PC)
PC-GF-## is also a kind of material used in notebook computer shell. Its raw material is petroleum, which becomes polyester chip particles after being processed by the polyester chip factory, and then becomes finished products after being processed by the plastic factory. Compared with PC+ABS, it lacks some characteristics of ABS, but PC-GF-## has its own characteristics.
Different specifications have different characteristics, such as PC-GF 10, PC-GF 15, PC-GF20, PC-GF30, etc. It has super high mechanical properties, heat resistance and dimensional stability, and can replace aluminum, lead or other metal stamping parts in different degrees of commercial appliances.
PC-GF-## is also called enhanced modified PC. It also has excellent impact strength, high heat resistance and good dimensional stability. It is stable in water, minerals and organic acids, partially soluble in aromatic carbohydrates, soluble in chloride, and decomposed under the action of strong alkali.
The water absorption of glass fiber and carbon fiber reinforced PC is very low. Strengthening PC can greatly improve the corrosion resistance to the environment. High fluidity PC can be used to make thin-walled parts below 1 mm, and the creep resistance and deformation resistance of PC modified materials are obviously improved. From a practical point of view, its heat dissipation performance is better than ABS plastic, and its heat dissipation is more uniform. Its biggest disadvantage is that it is fragile, and it will break when it falls. Our common optical discs are made of this material.
Fujitsu is the most famous company that uses this material. Many models use PC-GF20, and the whole shell is made of this material.
The material of PC-GF-# feels like metal in terms of surface and feel. If there is no logo on the notebook computer, it may be thought to be alloy if it is not observed very carefully from the outer surface. So pay attention to distinguish when buying, and don't be confused by its appearance.
3.ABS engineering plastics
ABS engineering plastics are probably the most used in notebook computers, and they are found in almost every notebook: some are used in the whole shell, some are only used in the screen top cover, and some are only used in the memory or hard disk cover.
In domestic notebook computers, this material is uniformly used for most notebook computers with nominal ordinary shell, while in foreign brands, ASB working plastics are mostly used for slightly larger notebook computers (that is, all-in notebook computers), such as the wrist rest and screen top cover of Sony Z 1 which we are familiar with. The biggest advantage of engineering plastics lies in its low price.
ABS engineering plastics, that is, PC+ABS (engineering plastic alloy), is called plastic alloy in Chinese in chemical industry, so it is named PC+ABS because this material not only has excellent heat and weather resistance, dimensional stability and impact resistance of PC resin, but also has excellent processing fluidity of ABS resin. Therefore, when it is applied to thin-walled and complex-shaped products, it can maintain its excellent performance and formability of materials composed of plastics and esters. At present, it is mainly used in communication equipment, household appliances, automobiles, computers and peripheral components.
The main disadvantages of ABS engineering plastics are heavy weight and poor thermal conductivity. In addition, ABS is also a carcinogenic chemical, which will cause cancer if inhaled into the human body to a certain extent. Of course, people only use laptops and generally don't inhale this chemical, but when users face laptops at close range for a long time, they will inhale a small amount of ABS odor, which is not good for health.
Generally speaking, ABS engineering plastics are adopted by most notebook computer manufacturers because of their low cost. At present, most notebook computers with plastic casings are ABS engineering plastics, while carbon fiber and polycarboacetic acid are relatively rare.