Discussion on the process flow of aluminum extruded profile shell of electronic cigarette

After the market contraction and industry reshuffle in 2015 and 2016, the e-cigarette industry finally ushered in a new development turning point in 2017. The global e-cigarette market showed a warming trend, and the sales volume further increased. And today's e-cigarette shell more and more personality, color is also more and more beautiful. But there are many complicated and tedious processes hidden behind the bright appearance.

E-cigarette shell production materials generally include plastic, stainless steel, aluminum, zinc, magnesium alloy, etc. today's main process is the most commonly used aluminum extrusion shell production process.

Making a small aluminum shell usually goes through the following processes: mold opening, extrusion, sawing, CNC machining (some need stamping, wire drawing), polishing, wire drawing, and final surface treatment: anodizing or spraying, electroplating, ceramic oxidation, etc.

1、 Open the mold.

Mold is designed according to the needs of high-precision specification of the tool, used to extrude the required specifications and cross-section of the profile products. Its design and maintenance should pay attention to the following points:

1. The structure of the mold should first meet the production needs, but also meet the common sense of physical mechanics, to ensure that the product can achieve the performance of the use.

2. The material selection and hardness of the die should be appropriate to avoid deformation, scratch and other hard damage in the extrusion process.

3. It is necessary to clean and inspect the die frequently, and repair the problem in time, so as to avoid scratch, burr and other hard damage in the extrusion process, which seriously affects the quality of industrial aluminum profile products.

2、 Extrusion.

Key points for aluminum profile extrusion process:

1. Temperature control: for extrusion production, extrusion temperature is the most basic and critical process factor. Extrusion temperature has great influence on product quality, production efficiency, die life and energy consumption.

2. Extrusion speed: the extrusion speed must be carefully controlled in the extrusion process. The extrusion speed has an important influence on the deformation thermal effect, deformation uniformity, recrystallization and solid solution process, mechanical properties and surface quality of products.

3. On machine quenching: the purpose of quenching is to keep the Mg2Si which is dissolved in the base metal at high temperature after it is quickly cooled to room temperature. The cooling rate is always proportional to the content of strengthening phase. The minimum hardening cooling rate of 6063 alloy is 38 ℃ / min, so it is suitable for air quenching. The cooling intensity can be changed by changing the number of fan and fan revolutions, so that the temperature of products before tension straightening can be reduced to below 60 ℃.

4. Profile straightening correction: there will be some deviation after the industrial aluminum profile is extruded and formed. After forming, straightening correction should be carried out by straightening machine. The industrial aluminum profile just extruded and formed should be corrected to the required tolerance range. Straightening correction must be completed by straightening machine to ensure its accuracy.

5. Artificial aging: aluminum profiles produced by extrusion have low hardness before aging and can not be used as finished products. Therefore, generally speaking, they must be aged to improve strength.

The above process must be strictly controlled according to the above requirements. If it is not well controlled, it is easy to have open line, deformation, surface sand hole, dark line, etc. Especially for the materials with dark lines, if the surface treatment is anodic oxidation, this step can not be seen. Only after anodic oxidation can we see a black line coming out of the whole product, causing great losses.

3、 Sawing and cutting.

The profile just extruded is generally 6 meters long. The profile factory will cut it into 2 meters or 2.5 meters according to the demand and send it to the aluminum products processing factory. Then the aluminum products factory will cut it into different lengths according to the drawing size requirements.

4、 CNC machining (some need stamping).

The length of sawing machine can't reach the drawing size. These materials must be put on CNC machine one by one for confidential processing. Of course, CNC machining is not only as simple as milling length, but also needs to machine different shapes (such as chamfering, drilling, opening windows, etc.) according to the product drawing. Some products also need to open stamping die to punch in the punch to achieve the shape you want.

5、 Polishing | wire drawing

After the above four steps, then the rough finished product of the electronic shell comes out. At this time, the surface of the shell is dirty and uneven, and there are many machine-made burrs left. At this time, the surface must be further treated.

1. Polishing: it is a kind of surface modification technology. It generally refers to a kind of processing method to change the physical properties of material surface by friction with the help of rough objects (sandpaper with high hardness particles, etc.), and the main purpose is to obtain specific surface roughness.

Cloth wheel, nylon wheel, hemp wheel and water grinding process can be selected according to the surface fineness of products. If the surface requirement of the product is not very high, it can be polished with cloth wheel and nylon wheel; if the surface requirement is high, it must be polished with hemp wheel or even water wheel. A lot of wax will be used in the grinding of Ma Lun, so the products polished by this method must be specially cleaned to remove wax. The aluminum case of mobile phones of big companies such as iPhone, Huawei and Xiaomi all use water grinding to achieve that polishing effect. Of course, these costs are higher.

2. Wire drawing: it is a method to improve the surface finish of the workpiece by using the reciprocating motion of the wire drawing cloth and rubbing it back and forth on the surface of the workpiece. The surface texture is linear, which can improve the surface quality and mask the slight scratches on the surface.

6、 Surface treatment: anodizing or spraying, electroplating, ceramic oxidation. Due to space limitation, only the most common anodic oxidation treatment is introduced here.

In order to overcome the surface hardness, wear resistance and other defects of aluminum alloy, expand the scope of application and prolong the service life, surface treatment technology has become an indispensable part in the use of aluminum alloy, and anodization technology is the most widely used and the most successful.

Anodization of aluminum is a kind of electrolytic oxidation process. In this process, the surface of aluminum and aluminum alloy is usually transformed into an oxide film, which has protective, decorative and some other functional properties.

The general process flow of aluminum anodizing is as follows:

1. Degreasing. Its purpose is to remove the industrial lubricating oil and anti-corrosion oil on the surface of aluminum profile, as well as the dirt and impurities attached to the surface of profile, to ensure the uniform alkali corrosion of aluminum profile and the cleanness of alkali corrosion groove.

2. Surface sandblasting (this item is not necessary, only applicable to sandblasted products). It is a process of cleaning and roughening the surface of the substrate by using the impact of high-speed sand flow, so that the surface of the workpiece can obtain a certain degree of cleanliness and different roughness.

3. Hang it up. The workpiece is fixed on a specific hanger (too loose hanger will lead to poor conductivity, resulting in uneven or no coloring in the later stage).

4. Acid etching. The primary purpose of the acid etching process is to remove the oxide formed by the oxidation of other metal elements on the surface of aluminum profile and the oxide film naturally formed by the profile; after the acid etching treatment, it is necessary to wash immediately, and the washing temperature should be controlled as early as 50 ℃, so as to avoid the occurrence of flow marks on the surface of the profile, and then carry out active water cleaning. Due to the copper element in the aluminum profile, the surface darkens after acid corrosion test, so it needs to be soaked in nitric acid solution for 3-5 minutes to make the surface bright silver.

5. Alkali corrosion. The primary purpose of alkali etching process is to remove the residual material and transmutation layer on the surface of aluminum profile in the oxidation process, and to eliminate the scratch defects left on the surface of aluminum profile in the kneading process. After alkali etching, the product will feel more soft and smooth, but it will also lead to dark lines in some products with poor profile quality.

6. Neutralization. The purpose of neutralization process is to remove the copper, manganese, iron, silicon and other alloy elements or impurities insoluble in alkaline solution left on the surface of aluminum profile after acid etching and alkaline etching. The general method to neutralize the alkaline solution left on aluminum profile after alkaline etching is to use 30% - 50% nitric acid solution to cast and form high silicon aluminum alloy A mixture of nitric acid and hydrofluoric acid with a volume ratio of 1:3 was used. Silicon reacts with hydrogen and hydrofluoric acid to form fluorosilicic acid, which is separated from aluminum surface.

7. Anodic conductive oxidation. The anodizing method of aluminum profile is to use the solution (commonly 10-20% H2SO4 as electrolyte) as the medium, and select the tip discharge to form an oxide film on the surface of aluminum profile, so that the aluminum profile has super corrosion resistance. Because the protective layer obtained by anodizing aluminum profile has high hardness and corrosion resistance, and the standard thickness is 10-12 μ, it can be better The anti-oxidation function of advanced aluminum profile and the beauty of advanced profile.

8. Dyeing. After conductive treatment, aluminum surface will be attached with a layer of oxide film, then put in the color tank can be colored.

9. Sealing (heating or chromate solution to seal the pores in the surface oxide layer). After anodizing, the surface will form micropores, which are easy to be oxidized and corroded in the process of application, so sealing treatment should be carried out after anodizing.

10. Hang it down. (remove the finished product from the hanger)

After the above tedious processes, the small aluminum shell was finally made and finally presented to the world.

The above information is carefully sorted out by Shenzhen Xingsheng aluminum products Co., Ltd. in combination with its own years of experience in the aluminum products processing industry. Since its establishment, Shenzhen Xingsheng aluminum products has been focusing on the production and processing of aluminum products. After years of exploration and research in this industry, it has accumulated a set of experience on how to quickly produce high-quality aluminum shell with controllable finished products. We warmly welcome customers at home and abroad to consult and customize electronic cigarettes, smart home, power bank, data cable and other aluminum shell products. We hope to work closely with you in the coming days to create a brilliant future hand in hand!