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IPad Tablet PC Case Cover Analysis On Technical Difficulties Of Aluminum Production Technology

Dongguan Kinga Packing Co.,Ltd | Updated: Sep 28, 2017

First, the market situation and prospects analysis

According to market research firm IDC data show that the first quarter of 2011 to the second quarter of the global Tablet PC sales plummeted. The second quarter sales of 13.6 million units, an increase of 303.8%, the third quarter sales of 18.1 million units, an increase of 264.5%. At the same time, IDC expects global sales in 2012 is expected to reach 63.3 million units.

If the average amount of aluminum for each tablet is 2kg, the amount of aluminum used in this product is 12,600 tons in 2012, about twice the amount of aluminum for rail vehicles, and it is not the outbreak of Tablet PC sales. As an electronic product, like a cell phone, its replacement cycle is relatively short. With the rapid increase in penetration, Tablet PC late demand will be very large, so the product will become another important industrial aluminum market.

Tablet PC aluminum shell with a good material is generally made of composite materials, more than 10 percent of the alloy, the other is the polymer material. If the use of pure alloy to do it is generally made of sheet metal, aluminum alloy, then the surface treatment is generally spray, drawing or oxidation, more high-end surface treatment I do not know, the alloy may be in order to reduce the cost of 6 series Aluminum alloy, its strength is basically able to meet the requirements, and the surface treatment is relatively easy, other aluminum alloy surface treatment effect is not very satisfactory.

Second, the current main problems

As a high-end electronic products Tablet PC, the shell has a strong decorative, not only mechanical performance is better, and the appearance of beautiful appearance. So after machining and surface treatment of aluminum shell, do not allow black spots, miscellaneous points, markings, scratches and other naked eye can be found defects. Because the machining is used for CNC machining, so the aluminum plate before processing the dimensional accuracy requirements are very high (250mm wide plane gap can not exceed 0.05mm), so to bring a great challenge to the production.

At present, there are many domestic manufacturers in the production of the product, but really do a good few, there are low yield, high scrap rate, especially after processing, large amount of scrap, resulting in a substantial increase in processing costs. The main flaws are as follows:

1, the plane gap tolerance;

2, the size of precision tolerance;

3, short tail is too long;

4, slag generated by oxides or other inclusions;

5, grain coarse;

6, low strength;

7, layer, bubble, from the skin;

8, dark spots, snow spots.

Some of the above defects are found in the machining before, this kind of scrap caused by the single loss is not great, but the larger number. This kind of scrapping is often due to the plane gap tolerance, size tolerance and low strength caused by, because these defects can be tested before machining. A considerable part of the defect is to be processed in the chemical surface after machining to be able to find this kind of scrap caused by a single loss is very large. And the kind of scrapped is often due to shrinkage, oxide or other inclusions generated slag, coarse grain, layer, bubble, from the skin, dark spots, snow spots and other reasons.

Third, the key technology

There are many reasons for the above defects, there are inherent deficiencies in the production equipment, there are unreasonable design of the production process, the operator's improper control of the scene. To solve the above problems, a substantial increase in yield, pass rate, mainly from the following aspects:

1, casting side

1), because the wall thickness of such products is relatively thick, the extrusion ratio is usually not large, when the amount of metal deformation is not. As the plane gap requirements are very high, quenching strength can not be too much, so more prone to coarse grain phenomenon. To solve this problem, in the alloy ratio, smelting process, casting process and other aspects should focus on the ingot of the grain size, should be appropriate to increase the number of fine grain elements, to strengthen the refining and casting cooling control.

2), in order to avoid the oxide or other inclusions into the ingot, and then entrained into the extrusion products, casting should use a good ceramic filter plate, the effective oxide or other slag filter out.

2, Tablet PC shell aluminum extrusion

1) In order to make the product evenly and with the same performance, the ingot should be homogenized and the homogenization process can be carried out according to the ordinary 6063 alloy.

2) because the product is a single species, large quantities of the type, it is recommended to use short bar fast heating furnace, it is best to make the ingot temperature gradient. First of all, the first long-spindle hot shear cut out of the ingot port deformation of a larger impact on the subsequent stripping effect, easily lead to the ingot skin flow to the extrusion products inside; second, a large number of cracks on the mouth, Crushing, it is difficult to exhaust thoroughly, will cause the extrusion product to produce bubbles; Third, the rapid heating of shorts, is conducive to maintaining the homogenization of the ingot after the state; Fourth, the short spindle gradient heating (ingot front temperature of about 500 ℃, the end temperature of about 460 ℃ is appropriate), is conducive to reducing the formation of extrusion products tail, is conducive to the consistency of mechanical properties of products.

From the cost and the ingot temperature control comprehensive consideration, I think it is best to use the first gas heating, after heating with induction furnace.

3) ingot hot peeling

In order to avoid the surface of the ingot surface oxide and other debris into the extruded product inside, should be heated in the ingot into the Sheng barrel into the "stripping" treatment, the casting of the skin and so removed. The thickness of the peeling is related to the diameter of the ingot and the quality of the ingot, usually 3-5 mm.

4) quenching treatment

Because the product is 6063T6 state, and the wall thickness is thick, the plane gap is higher. Such as air-cooled, cooling rate is too low, quenching effect is poor, the product is too large grain, mechanical properties are low. If you use the sink or spray cooling, the cooling rate is too fast, and the cooling is not uniform, resulting in serious deformation of the product, the plane gap is extremely poor. To solve this problem, a combination of a variety of cooling forms should be used. After the test, the best solution is the first 4-5 meters mixed with a fume cooling, the product temperature down to about 250 degrees, and then 1-2 m spray. Of course, the layout of the spray to pay attention to, must be the product around the point of uniform cooling. After this quenching, the product temperature is reduced to about 100 ° C. If coupled with a section of air-cooled (4 meters is better), the effect is better. This treatment, both to achieve the requirements of cooling strength, give full play to the mechanical properties of the alloy, but also reduce the deformation of the product to ensure that the requirements of the plane gap, and to avoid the water mark, dark spots and other defects. The link is very important, but often easy to be overlooked.

Tablet PC shell with aluminum quenching

Aluminum extrusion is a systematic project, each link will have a greater impact on product quality, every link should cause enough attention. The above describes the link is the product is different from other building materials to pay attention to, and often is easy to be ignored, so for the focus that the hope that the production enterprises can help.