A processing technology of 3C accessories based on 7 series aluminum alloy

Abstract

The application provides a processing technology of 3C accessories based on a 7-series aluminum alloy, the 7-series aluminum alloy contains 1.5-2% of magnesium, 4-6% of zinc, 0.01-0.1% of copper, 0.03-0.08% of silicon, 0.02-0.03% of titanium and the rest of aluminum in terms of weight fraction; the 7-series aluminum alloy is transferred into a barrel after being prepared in a liquid or semi-solid state, and the barrel is docked with a mold; the 7-series aluminum alloy in the barrel is sent into the mold to fill the mold; a moving die of the mold is provided with at least one extrusion pin, the extrusion pin penetrates into a cavity of the mold, the extrusion pin is in a retreat state during filling, the extrusion pin is inserted into the cavity after filling is completed with a delay of 1-3S, and the extraction time of the extrusion pin is 8-13S. The 3C accessory of the scheme can form a uniform, dense and appropriate thickness oxide layer in the anodic oxidation process, has better corrosion resistance, a color-uniform outer surface and a stronger tensile strength.

Description

Technical Field

[0001] The present invention relates to the field of 3C accessories processing, and in particular to a processing technology for 3C accessories based on 7 series aluminum alloy. Background Art

[0002] With the development of the demand for thinner and lighter 3C accessories, the requirements for frames are gradually increasing. Aluminum alloy frames are characterized by being thin and light and high-strength, and are being adopted by more and more manufacturers. At present, the 6-series aluminum alloy has a relatively high degree of commercialization. The 6-series aluminum alloy has magnesium and silicon as the main additives and has better corrosion resistance. As manufacturers further pursue the thinning of mobile phones, the strength of the 6-series aluminum alloy is difficult to meet the requirements. The 7-series aluminum alloy has magnesium, zinc and copper as the main additives and has ultra-high hardness. It is widely used in the aviation field. The application of the 7-series aluminum alloy to 3C accessories can meet the demand for higher hardness of 3C accessories. However, the surface quality of the 7-series aluminum alloy is poor and it is easy to produce element segregation. Therefore, it is difficult to obtain a better anodizing effect by directly applying the 7-series aluminum alloy to 3C accessories, and the oxide layer is prone to corrosion and shedding.

[0003] Therefore, it is necessary to provide a processing technology for 3C accessories based on 7 series aluminum alloy. Summary of the Invention

[0004] The first aspect of the present invention provides a processing technology for 3C accessories based on 7 series aluminum alloy, wherein the 7 series aluminum alloy contains, by weight, 1.5-2% magnesium, 4-6% zinc, 0.01-0.1% copper, 0.03-0.08% silicon, 0.02-0.03% titanium and the remainder aluminum. The 7 series aluminum alloy is prepared into a liquid or semi-solid state and then transferred to a barrel, and the barrel is docked with a mold; the 7 series aluminum alloy in the barrel is fed into the mold for filling; the movable mold of the mold is provided with at least one extrusion pin, which penetrates into the mold cavity of the mold. The extrusion pin is in a retracted state during filling, and the extrusion pin is inserted into the mold cavity with a delay of 1-3S after filling is completed. The removal time of the extrusion pin is 8-13S.

[0005] Beneficial effects: This solution reduces the content of copper and silicon. Copper dissolves much faster than aluminum during the anodizing process, which will cause the oxide film to be too thin and affect the color of the oxide layer. Silicon does not react during the anodizing process, thereby preventing the oxidation of aluminum and resulting in uneven oxide layer thickness. The above problems can be avoided by reducing the content of copper and silicon; by reducing the zinc content and using titanium as a refiner, the formation of coarsened MgZn2 can be reduced, the risk of stress corrosion cracking can be reduced, and the fluidity of the melt can be improved; however, reducing the content of zinc, copper and silicon will cause the fluidity of the 7 series aluminum alloy to further decrease. Therefore, this solution combines indirect extrusion and local extrusion processes to reduce the shrinkage problem caused by reduced fluidity. Therefore, the 3C accessories of this solution can form a uniform, dense and appropriately thick oxide layer during the anodizing process, with better corrosion resistance and a uniformly colored outer surface and strong tensile strength.

[0006] Furthermore, it contains 4.5-5.5% zinc. If the zinc content is too low, it will affect the formation of the MgZn2 strengthening phase, resulting in low tensile strength of the 3C parts; if the zinc content is too high, it will promote the coarsening of the MgZn2 strengthening phase. The combination of the above zinc content and the preparation process can produce 3C parts with both tensile strength and corrosion resistance.

[0007] Furthermore, it contains 0.02-0.06% copper. If the copper content is too low, it will not play an alloying role to improve the strength of 3C accessories; if the copper content is too high, it will affect the oxide layer, ultimately affecting the surface quality and corrosion resistance.

[0008] Furthermore, the 7-series aluminum alloy contains 1.5% magnesium, 4.5% zinc, 0.03% copper, 0.03% silicon, 0.02% titanium, and the balance aluminum. The above-mentioned ratio combined with the preparation process can achieve optimal corrosion resistance and tensile strength.

[0009] Furthermore, the filling speed is 180-220 mm / s. In this process, the 7 series aluminum alloy has poor fluidity and requires a higher filling speed to avoid defects such as shrinkage and pores.

[0010] Furthermore, the filling pressure is 140-200 MPa, and the holding time is 10-30 seconds. If the holding pressure is too low, the material will have difficulty overcoming flow resistance during the holding phase to fully fill the mold cavity, resulting in a large number of defects such as shrinkage cavities. If the holding pressure is too high, it may cause material overflow. If the holding time is too short, the casting temperature will be too high, resulting in insufficient shrinkage compensation. If the holding time is too long, production efficiency will be affected.

[0011] Furthermore, the extrusion depth is 2-6 mm. If the extrusion depth is too small, the metal liquid added is insufficient and it is difficult to achieve the shrinkage compensation effect; if the extrusion depth is too large, it is easy to cause damage to the casting.

[0012] Furthermore, the extrusion pin is arranged on the plane or bottom hole of the thick wall of the 3C accessory. The thick wall can allow a greater extrusion depth and achieve a better shrinkage feeding effect.

[0013] A second aspect of the present invention provides a 3C accessory, characterized in that it is prepared using the above-mentioned 3C accessory processing technology.

[0014] The 3C accessories obtained by the above preparation method have excellent anodizing effect, corrosion resistance and tensile strength. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the 3C accessories of Example 1.

[0016] Figure 2 Schematic diagram of the 3C accessories of Comparative Example 1.

[0017] Figure 3 Comparison diagram of the 3C accessories of Example 1 (top) and Comparative Example 1 (bottom). DETAILED DESCRIPTION

[0018] For ease of understanding of the present application, the present application will be described more fully below. The present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0019] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. In the description of this application, the meaning of "several" is at least one, such as one, two, etc., unless otherwise clearly and specifically defined.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0021] In this application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0022] In this application, when referring to numerical ranges, unless otherwise specified, the numerical ranges are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges can be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges subsumed therein.

[0023] Unless otherwise specified, the percentage contents mentioned in this application refer to mass percentage for solid-liquid mixture and solid-solid mixture, and refer to volume percentage for liquid-liquid mixture.

[0024] The percentage concentrations mentioned in this application, unless otherwise specified, refer to the final concentration, which refers to the percentage of the added component in the system after the addition of the component.

[0025] The temperature parameters in this application, unless otherwise specified, allow for both constant temperature treatment and treatment within a certain temperature range. The constant temperature treatment allows for temperature fluctuations within the precision range of instrument control.

[0026] The "particles" mentioned in this application, or materials with a defined particle size distribution, are not necessarily spherical in shape but may be irregular, primary or secondary. The particle size of irregular particles is the average of their maximum and minimum diameters.

[0027] Example 1: This example provides a processing technology for 3C accessories based on 7 series aluminum alloy (all examples and comparative examples are mobile phone frames), which is prepared by optimizing the 7 series aluminum alloy formula and combining indirect extrusion and local extrusion, and includes the following steps:

[0028] Prepare 10 kg of 7 series aluminum alloy melt: 1.5% magnesium, 6% zinc, 0.1% copper, 0.08% silicon, 0.03% titanium and the balance aluminum are weighed, mixed, heated, degassed and deslaged to form an aluminum alloy melt, and kept warm at 680°C.

[0029] Indirect extrusion and partial extrusion: The extrusion pin is installed in the bottom hole of the mold corresponding to the thick wall of the casting and is placed in a retracted state. The 7 series aluminum alloy melt is transferred into the barrel, and the barrel and mold are docked in preparation for injection. The barrel is preheated to 250°C. The melt is injected into the mold at a speed of 220mm / s. After filling is completed, the pressure is maintained at 200MPa for 15 seconds. The extrusion pin is activated 3 seconds after the start of filling. The extrusion depth is 6mm and maintained for 13 seconds before removal. After the holding time is over, the mold is opened and the casting is removed.

[0030] T6 heat treatment: solution treatment at 550°C for 1 hour, aging treatment at 185°C for 10 hours to obtain 3C castings.

[0031] Anodizing: CNC machining and anodizing of the casting surface.

[0032] Example 2: This example provides a processing technology for 3C accessories based on 7 series aluminum alloy, which is prepared by optimizing the 7 series aluminum alloy formula and combining indirect extrusion and local extrusion, comprising the following steps:

[0033] Prepare 10 kg of 7 series aluminum alloy melt: weigh 2% magnesium, 4% zinc, 0.1% copper, 0.03% silicon, 0.02% titanium and the balance aluminum, mix them, heat, degas and deslag to form an aluminum alloy melt, and keep it at 680°C.

[0034] Indirect extrusion and partial extrusion: The extrusion pin is installed in the bottom hole of the mold corresponding to the thick wall of the casting and is placed in a retracted state. The 7 series aluminum alloy melt is transferred into the barrel, and the barrel and mold are docked in preparation for injection. The barrel is preheated to 250°C. The melt is injected into the mold at a speed of 220mm / s. After filling is completed, the pressure is maintained at 200MPa for 15 seconds. The extrusion pin is activated 3 seconds after the start of filling. The extrusion depth is 6mm and maintained for 13 seconds before removal. After the holding time is over, the mold is opened and the casting is removed.

[0035] T6 heat treatment: solution treatment at 550°C for 1 hour, aging treatment at 185°C for 10 hours to obtain 3C castings.

[0036] Anodizing: CNC machining and anodizing of the casting surface.

[0037] Example 3: This example provides a processing technology for 3C accessories based on 7 series aluminum alloy, which is prepared by optimizing the 7 series aluminum alloy formula and combining indirect extrusion and local extrusion, comprising the following steps:

[0038] Prepare 10 kg of 7 series aluminum alloy melt: 1.5% magnesium, 5.5% zinc, 0.1% copper, 0.08% silicon, 0.03% titanium and the balance aluminum are weighed, mixed, heated, degassed and deslaged to form an aluminum alloy melt, and kept warm at 680°C.

[0039] Indirect extrusion and partial extrusion: The extrusion pin is installed in the bottom hole of the mold corresponding to the thick wall of the casting and is placed in a retracted state. The 7 series aluminum alloy melt is transferred into the barrel, and the barrel and mold are docked in preparation for injection. The barrel is preheated to 250°C. The melt is injected into the mold at a speed of 220mm / s. After filling is completed, the pressure is maintained at 200MPa for 15 seconds. The extrusion pin is activated 3 seconds after the start of filling. The extrusion depth is 6mm and maintained for 13 seconds before removal. After the holding time is over, the mold is opened and the casting is removed.

[0040] T6 heat treatment: solution treatment at 550°C for 1 hour, aging treatment at 185°C for 10 hours to obtain 3C castings.

[0041] Anodizing: CNC machining and anodizing of the casting surface.

[0042] Example 4: This example provides a processing technology for 3C accessories based on 7 series aluminum alloy, which is prepared by optimizing the 7 series aluminum alloy formula and combining indirect extrusion and local extrusion, comprising the following steps:

[0043] Prepare 10 kg of 7 series aluminum alloy melt: 1.5% magnesium, 6% zinc, 0.06% copper, 0.08% silicon, 0.03% titanium and the balance aluminum are weighed, mixed, heated, degassed and deslaged to form an aluminum alloy melt, and kept warm at 680°C.

[0044] Indirect extrusion and partial extrusion: The extrusion pin is installed in the bottom hole of the mold corresponding to the thick wall of the casting and is placed in a retracted state. The 7 series aluminum alloy melt is transferred into the barrel, and the barrel and mold are docked in preparation for injection. The barrel is preheated to 250°C. The melt is injected into the mold at a speed of 220mm / s. After filling is completed, the pressure is maintained at 200MPa for 15 seconds. The extrusion pin is activated 3 seconds after the start of filling. The extrusion depth is 6mm and maintained for 13 seconds before removal. After the holding time is over, the mold is opened and the casting is removed.

[0045] T6 heat treatment: solution treatment at 550°C for 1 hour, aging treatment at 185°C for 10 hours to obtain 3C castings.

[0046] Anodizing: CNC machining and anodizing of the casting surface.

[0047] Example 5: This example provides a processing technology for 3C accessories based on 7 series aluminum alloy, which is prepared by optimizing the 7 series aluminum alloy formula and combining indirect extrusion and local extrusion, comprising the following steps:

[0048] Prepare 10 kg of 7 series aluminum alloy melt: 1.5% magnesium, 4.5% zinc, 0.03% copper, 0.03% silicon, 0.02% titanium and the balance aluminum are weighed, mixed, heated, degassed and deslaged to form an aluminum alloy melt, and kept warm at 680°C.

[0049] Indirect extrusion and partial extrusion: The extrusion pin is installed in the bottom hole of the mold corresponding to the thick wall of the casting and is placed in a retracted state. The 7 series aluminum alloy melt is transferred into the barrel, and the barrel and mold are docked in preparation for injection. The barrel is preheated to 250°C. The melt is injected into the mold at a speed of 220mm / s. After filling is completed, the pressure is maintained at 200MPa for 15 seconds. The extrusion pin is activated 3 seconds after the start of filling. The extrusion depth is 6mm and maintained for 13 seconds before removal. After the holding time is over, the mold is opened and the casting is removed.

[0050] T6 heat treatment: solution treatment at 550°C for 1 hour, aging treatment at 185°C for 10 hours to obtain 3C castings.

[0051] Anodizing: CNC machining and anodizing of the casting surface.

[0052] Example 6: This example provides a processing technology for 3C accessories based on 7 series aluminum alloy, which is prepared by optimizing the 7 series aluminum alloy formula and combining indirect extrusion and local extrusion, and includes the following steps:

[0053] Prepare 10 kg of 7 series aluminum alloy melt: 1.5% magnesium, 6% zinc, 0.1% copper, 0.08% silicon, 0.03% titanium and the balance aluminum are weighed, mixed, heated, degassed and deslaged to form an aluminum alloy melt, and kept warm at 650°C.

[0054] Indirect extrusion and partial extrusion: The extrusion pin is installed on the flat surface of the mold corresponding to the thick wall of the casting and is placed in a retracted state. The 7 series aluminum alloy melt is transferred into the barrel, which is then docked with the mold in preparation for injection. The barrel is preheated to 250°C. The melt is injected into the mold at a speed of 180mm / s. After filling is complete, the pressure is maintained at 140MPa for 30 seconds. The extrusion pin is activated 3 seconds after the start of filling. The extrusion depth is 6mm and maintained for 13 seconds before removal. After the holding time is over, the mold is opened and the casting is removed.

[0055] T6 heat treatment: solution treatment at 550°C for 1 hour, aging treatment at 185°C for 10 hours to obtain 3C castings.

[0056] Anodizing: CNC machining and anodizing of the casting surface.

[0057] Example 7: This example provides a processing technology for 3C accessories based on 7 series aluminum alloy, which is prepared by optimizing the 7 series aluminum alloy formula and combining indirect extrusion and local extrusion, comprising the following steps:

[0058] Prepare 10 kg of 7 series aluminum alloy melt: 1.5% magnesium, 4.5% zinc, 0.03% copper, 0.03% silicon, 0.02% titanium and the balance aluminum are weighed, mixed, heated, degassed and deslaged to form an aluminum alloy melt, cooled to obtain a melt with a solid phase fraction of 30%, and kept warm.

[0059] Indirect extrusion and partial extrusion: The extrusion pin is installed in the bottom hole of the mold corresponding to the thick wall of the casting and is placed in a retracted state. The 7 series aluminum alloy melt is transferred into the barrel, and the barrel and mold are docked in preparation for injection. The barrel is preheated to 250°C. The melt is injected into the mold at a speed of 220mm / s. After filling is completed, the pressure is maintained at 200MPa for 15 seconds. The extrusion pin is activated 1 second after the start of filling. The extrusion depth is 2mm and maintained for 8 seconds before removal. After the holding time is over, the mold is opened and the casting is removed.

[0060] T6 heat treatment: solution treatment at 550°C for 1 hour, aging treatment at 185°C for 10 hours to obtain 3C castings.

[0061] Anodizing: CNC machining and anodizing of the casting surface.

[0062] Comparative Example 1: This comparative example provides a processing technology for 3C accessories, comprising the following steps:

[0063] Prepare 10 kg of 7 series aluminum alloy melt: 1.5% magnesium, 6% zinc, 0.1% copper, 0.08% silicon, 0.03% titanium and the balance aluminum are weighed, mixed, heated, degassed and deslaged to form an aluminum alloy melt, and kept warm at 680°C.

[0064] Indirect extrusion: Install the extrusion pin in the bottom hole of the mold corresponding to the thick wall of the casting and place it in the retracted position. Transfer the 7 series aluminum alloy melt into the barrel, dock the barrel with the mold and prepare for injection. The barrel is preheated to 250°C. The melt is injected into the mold at a speed of 220mm / s. After filling, the pressure is maintained at 200MPa for 15 seconds. After the pressure holding time is over, the mold is opened and the casting is removed.

[0065] T6 heat treatment: solution treatment at 550°C for 1 hour, aging treatment at 185°C for 10 hours to obtain 3C castings.

[0066] Anodizing: CNC machining and anodizing of the casting surface.

[0067] Comparative Example 2: This comparative example provides a processing technology for 3C accessories, comprising the following steps:

[0068] Prepare 10 kg of 7 series aluminum alloy melt: weigh 2% magnesium, 8% zinc, 1% copper, 0.08% silicon, 0.03% titanium and the balance aluminum, mix them, heat, degas and deslag to form an aluminum alloy melt, and keep it at 680°C.

[0069] Indirect extrusion: Install the extrusion pin in the bottom hole of the mold corresponding to the thick wall of the casting and place it in the retracted position. Transfer the 7 series aluminum alloy melt into the barrel, dock the barrel with the mold and prepare for injection. The barrel is preheated to 250°C. The melt is injected into the mold at a speed of 220mm / s. After filling, the pressure is maintained at 200MPa for 15 seconds. After the pressure holding time is over, the mold is opened and the casting is removed.

[0070] T6 heat treatment: solution treatment at 550°C for 1 hour, aging treatment at 185°C for 10 hours to obtain 3C castings.

[0071] Anodizing: CNC machining and anodizing of the casting surface.

[0072] Comparative Example 3: This comparative example provides a processing technology for 3C accessories, comprising the following steps:

[0073] Prepare 10 kg of 7 series aluminum alloy melt: weigh 2% magnesium, 8% zinc, 1% copper, 0.08% silicon, 0.03% titanium and the balance aluminum, mix them, heat, degas and deslag to form an aluminum alloy melt, and keep it at 680°C.

[0074] Indirect extrusion and partial extrusion: The extrusion pin is installed in the bottom hole of the mold corresponding to the thick wall of the casting and is placed in a retracted state. The 7 series aluminum alloy melt is transferred into the barrel, and the barrel and mold are docked in preparation for injection. The barrel is preheated to 250°C. The melt is injected into the mold at a speed of 220mm / s. After filling is completed, the pressure is maintained at 200MPa for 15 seconds. The extrusion pin is activated 3 seconds after the start of filling. The extrusion depth is 6mm and maintained for 13 seconds before removal. After the holding time is over, the mold is opened and the casting is removed.

[0075] T6 heat treatment: solution treatment at 550°C for 1 hour, aging treatment at 185°C for 10 hours to obtain 3C castings.

[0076] Anodizing: CNC machining and anodizing of the casting surface.

[0077] The 3C accessories obtained in Examples 1-7 and Comparative Examples 1-3 were tested. The tensile strength was tested using the method according to ASTM-B557 standard, the anode surface effect was tested by visual observation, and the corrosion test was performed using the method of GB / T10125, resulting in the following Table 1.

[0078] Table 1 3C accessories test results

[0079]

[0080] According to the data in Table 1, the tensile strength, surface quality and corrosion resistance of Examples 1-7 are better than those of Comparative Examples 1-3. This is because the present solution combines the optimized 7-series aluminum alloy formula with indirect extrusion and local extrusion processes, wherein the 7-series aluminum alloy formula reduces the content of copper and silicon, can form a uniform oxide layer, obtain good corrosion resistance and color uniformity after oxidation; by reducing the zinc content and using titanium as a refiner, the formation of coarsened MgZn2 can be reduced, the risk of stress corrosion cracking can be reduced, and the fluidity of the melt can be improved; the indirect extrusion process and the local extrusion process reverse the defects such as shrinkage cavities and shrinkage cavities caused by the poor fluidity of the melt during the die-casting process due to the optimization of the formula. In this way, the 3C accessories of this solution can form a uniform, dense and appropriately thick oxide layer during the anodizing process, have better corrosion resistance and a uniformly colored outer surface and have strong tensile strength. As shown in FIG. Figure 1-3 As shown, the 3C accessories of Example 1 have no obvious pores, the anode has no discoloration and no flow marks, while the 3C accessories of Comparative Example 1 have obvious flow marks and pores. Comparative Example 1 did not use local extrusion for shrinkage feeding, because the melt fluidity of this formula is poor, and the casting has more shrinkage cavities, which affects its tensile strength and surface quality. Comparative Example 2 used a conventional aluminum alloy with high magnesium, zinc and copper content. Compared with Comparative Example 1, the quality of its surface oxide layer is poor and its corrosion resistance is poor. Comparative Example 3 used a conventional aluminum alloy with high magnesium, zinc and copper content combined with indirect extrusion and local extrusion processes. It has fewer pores than Comparative Example 2, but its anodizing quality and corrosion resistance are not significantly improved.

[0081] Example 3 uses an optimal zinc content, which has better tensile strength. Example 4 uses an optimal copper content, and its oxide layer is less likely to fall off. Example 5 uses the most preferred 7-series aluminum alloy formula, and its tensile strength, surface quality, and corrosion resistance are improved. Example 7 uses the most preferred 7-series aluminum alloy formula and further forms the aluminum alloy melt into a semi-solid melt with a solid phase fraction of 30%, and its tensile strength is further improved compared to Example 5.

[0082] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0083] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A processing technology for 3C accessories based on 7 series aluminum alloy, characterized in that: The 3C accessory is a mobile phone frame. The 7 series aluminum alloy contains, by weight, 1.5% magnesium, 4.5% zinc, 0.03% copper, 0.03% silicon, 0.02% titanium and the remainder aluminum. The 7 series aluminum alloy is prepared as a semi-solid melt with a solid phase fraction of 30% and then transferred to a barrel, and the barrel is docked with a mold; the 7 series aluminum alloy in the barrel is fed into the mold for filling, the filling speed is 180-220mm / s, the filling pressure is 140-200MPa, and the holding time is 10-30S; the movable mold of the mold is provided with at least one extrusion pin, the extrusion pin penetrates into the mold cavity, the extrusion pin is in a retracted state during filling, and the extrusion pin is inserted into the mold cavity with a delay of 1-3S after filling is completed, and the removal time of the extrusion pin is 8-13S.

2. The processing technology according to claim 1, characterized in that: The extrusion depth of the extrusion pin is 2-6 mm.

3. The processing technology according to claim 1, characterized in that: The extrusion pin is arranged on the thick-walled plane or bottom hole of the 3C accessory.

4. A 3C accessory, characterized in that: It is prepared using the processing technology of the 3C accessories described in any one of claims 1-3.

Images