CN106455391B

CN106455391B - 3C electronic product shell and preparation method thereof

Info

Publication number: CN106455391B
Application number: CN201610868230.9A
Authority: CN
Inventors: 唐臻; 张维; 王长明; 刘建; 张加赞; 谢守德
Original assignee: Guangdong Chuangshi Intelligent Equipment Group Co ltd
Current assignee: Guangdong Chuangshi Intelligent Equipment Group Co ltd
Priority date: 2016-09-28
Filing date: 2016-09-28
Publication date: 2022-03-22
Anticipated expiration: 2036-09-28
Also published as: CN106455391A

Abstract

The invention discloses a 3C electronic product shell and a preparation method thereof, wherein the electronic product shell comprises a metal structural part, a plurality of antenna splitting position micro-seams are arranged between the back surface and the front surface of the metal structural part in a penetrating manner, non-conductive pre-injection molding materials are filled in the antenna splitting position micro-seams, the back surface of the metal structural part is provided with a secondary injection molding plastic structure, and the plastic structure, the pre-injection molding materials and the metal structural part are combined into a whole. The invention can completely eliminate the problem of exposure of the antenna splitting position on the surface of the metal shell of the electronic product, realizes complete and coherent appearance of the metal shell of the electronic product, has strong metal texture and simple manufacturing process.

Description

3C electronic product shell and preparation method thereof

Technical Field

The invention relates to a 3C electronic product shell and a preparation method thereof.

Background

With the development requirements of miniaturization, lightness, thinness, fashion and practicality of 3C (Computer, Communication, Consumer Electronics) electronic products, the shells of the existing electronic products are increasingly made of metal materials with light weight and high strength, such as aluminum alloy, stainless steel, titanium alloy and the like, so as to meet the requirements of thinner and thinner product thickness, higher and higher strength of the whole machine, light weight, outstanding texture and fast heat dissipation.

Although the strength and the texture of the shell of the electronic product can be improved by using the metal material, due to the problem of antenna signal shielding of the communication electronic product, the antenna is required to be processed and positioned on the metal piece and connected by using plastic, so that the signal problem of the communication electronic product is solved, and the structural member cannot keep a complete and coherent appearance effect.

Meanwhile, the width of the antenna cutting position of the metal shell of the communication electronic product is limited by the traditional processing mode, equipment, materials and cost, so that the filled plastic material is leaked on the appearance surface of the metal shell, a consumer can obviously see and has obvious hand feeling difference with the metal material, the metal texture of the shell and the experience effect of the consumer are greatly reduced, the appearance effect of high-end fashion cannot be met, and the appearance effect is difficult to eliminate.

Disclosure of Invention

The invention mainly aims to overcome the defects of the prior art and provide a 3C electronic product shell and a preparation method thereof, which can completely eliminate the problem of exposure of antenna splitting positions on the surface of a metal shell of an electronic product, realize complete and coherent appearance of the metal shell of the electronic product, have strong metal texture and simple manufacturing process.

In order to achieve the purpose, the invention adopts the following technical scheme:

the utility model provides a 3C electronic product casing, includes metal structure, run through between metal structure's the back and the front and seted up many antennas and cut a little seam, the antenna is cut a little seam intussuseption and is filled with non-conductive pre-injection molding material, metal structure's the back has secondary injection moulding's plastic structure, the plastic structure with pre-injection molding material and metal structure combines as an organic wholely.

Further:

the width of the antenna slitting position micro-slit is 0.03 mm-0.8 mm.

The spacing distance of the antenna splitting position micro-slits is more than 0.15 mm.

An anodic oxidation layer formed by anodic oxidation is formed on the metal surface of the front surface of the metal structural member except for the area of the antenna slitting position micro-seam, and the pre-injection material is a material with the color similar to or the same as that of the anodic oxidation layer, or a white or black material.

The front surface of the metal structural member is entirely covered with an anodic oxide film or an anodic-like oxide film formed by thermal transfer printing, and preferably, a primer layer is arranged between the front surface of the metal structural member and the anodic oxide film or the anodic-like oxide film.

The front surface of the metal structural member is integrally plated with an aluminum film layer, an anodic oxidation layer formed by anodic oxidation is formed on the aluminum film layer, and preferably, a primer layer is arranged between the front surface of the metal structural member and the aluminum film layer.

The utility model provides a metal blank for making 3C electronic product casing offer on the back of metal blank corresponding to the position that the position slit was cut to the antenna and extend to the gluey hole of walking between the back of metal blank and the front, the position slit is cut to the antenna is in communicate after the shaping comes out on the metal blank walk the gluey hole so that right the position slit is cut to the antenna is moulded plastics in advance, preferably, walk the deepest distance in gluey hole more than 0.2mm in the front of metal blank.

A preparation method for preparing the 3C electronic product shell comprises the following steps:

processing a penetrating antenna sub-positioning micro-slit between the back surface and the front surface of the metal blank, preferably processing by adopting a laser cutting or laser etching process or a CNC process;

pre-injection molding the antenna sub-position micro-gap by using a non-conductive pre-injection molding material, and filling the antenna sub-position micro-gap;

performing secondary injection molding on the back of the metal blank to form a plastic structure, wherein the plastic structure and the pre-injection molding material are integrally combined together with a set strength and are combined with the metal blank;

preferably, the metal blank is provided with a reinforcing structure to prevent the metal area cut off during the antenna slitting position micro-seam processing from deforming or separating and falling off; the reinforcing structure is removed before the second injection molding.

Further:

before the pre-injection molding is carried out, glue running holes which can be connected with the antenna sub-positioning micro-slits and penetrate through the metal blank but do not penetrate through the metal blank are machined on the back surface of the metal blank; before secondary injection molding, processing and removing the part with the glue running hole on the back surface of the metal blank to expose the antenna sub-parting micro-seam; and the glue running hole is processed before the antenna splitting position micro-seam is processed, or is processed after the antenna splitting position micro-seam is processed.

After the secondary injection molding, the method also comprises the following steps:

forming an anodic oxidation layer on the metal surface of the front surface of the metal structural part except for the area of the antenna splitting position micro-slit by an anodic oxidation process, wherein the pre-injection material is a material with a color similar to or the same as that of the anodic oxidation layer; or

Covering an anodic oxide film or an anodic oxide-like film on the front surface of the metal structural member integrally by a thermal transfer printing process, preferably, coating a primer layer on the front surface of the metal structural member and then performing thermal transfer printing; or

Plating an aluminum film layer on the front surface of the metal structural member, and forming an anodic oxidation layer on the aluminum film layer by an anodic oxidation process.

The invention has the beneficial effects that:

the 3C electronic product shell and the preparation method thereof provided by the invention are beneficial to eliminating the problem of exposure of the antenna splitting position on the surface of the metal shell of the electronic product, so that the metal shell of the electronic product has complete and coherent appearance, strong metal texture, simple manufacturing process and low manufacturing cost, is suitable for large-scale mass production, not only effectively meets the requirement of the appearance quality of the structural member of the 3C electronic product, but also has the advantages of easiness in manufacturing, low cost and practicability. The advantages of the invention are embodied in the following aspects:

1. the invention provides an integrally formed shell of a metal piece, a micro-seam non-conductive pre-injection molding material and a secondary injection molding material, which can realize the surface decoration of the full metal appearance of a 3C electronic product and is easy for large-scale mass production;

2. based on the structure and the process, the micro-seam processing (for example, through laser cutting or laser engraving process or CNC processing) is carried out, the width of the antenna sub-position of the shell of the communication electronic product can be reduced from 1.2mm to below 0.40mm, even below 0.15mm, the influence of the traditional processing mode on the overall consistency of the metal shell is greatly reduced, and the effect that the metal shell is difficult to distinguish by naked eyes is achieved;

3. based on the structure and the process, the traditional etching process effect can be realized, the structure and the process are safe and environment-friendly, the large-scale mass production is easy, the pollution of the processing process to the environment is avoided, and the process is green and environment-friendly;

4. by utilizing a twice injection molding mode, the fine micro-cracks at the antenna splitting position of the product are filled firstly, so that the non-conductive pre-injection molding material in the micro-cracks is combined with metal in high strength, the problem that the antenna splitting position of the traditional communication electronic metal shell product is easy to crack is solved, the processing and manufacturing yield is improved, and the production and manufacturing cost is reduced;

5. the processing and manufacturing yield is improved, the appearance effect is improved, meanwhile, the antenna signal of the communication electronic product is not influenced, and the method is suitable for metal shells of various structures such as a middle frame, a back cover and a ring, and has wide process practicability;

6. the overall unified metal appearance effect can be realized on the surface of the product through surface decoration modes such as anodic oxidation, PVD, thermal transfer printing and the like, the influence of the existing metal product appearance antenna splitting position on the product appearance is completely eliminated, and the overall coherent metal texture is realized on the surface of the product; the requirements of consumers on practicability, fashion and durability of 3C electronic products are met.

Drawings

FIGS. 1a and 1b illustrate CNC pre-machining of a metal structural blank according to an embodiment of the present invention;

FIGS. 2a-2c illustrate an embodiment of the present invention using laser cutting, laser etching, wire cutting, CNC processes to perform antenna micro-seam processing on a metal structure;

FIGS. 3a and 3b illustrate an embodiment of the present invention for surface treating a metallic structural member after forming micro-cracks and for first injection molding a micro-crack region to fill the micro-cracks;

FIGS. 4a and 4b illustrate CNC machining of an area to be provided with a plastic structure on a metal structural member after a first injection molding of an embodiment of the present invention;

FIGS. 5a and 5b illustrate an embodiment of the present invention in which a metal structural component of a product is surface treated and injection molded a second time to form a plastic structure within the product;

FIGS. 6a and 6b illustrate that the CNC fine machining of the front surface of the product after the second injection molding and the CNC machining of the holes of the functional structures, such as the side holes of a camera, a key, a power key and the like, are performed to remove the allowance of the front surface of the product according to the embodiment of the invention;

FIGS. 7a and 7b illustrate an embodiment of the present invention finishing an area of a product having assembly and dimensional accuracy requirements on the back side and separating the product from the excess metal blank;

FIGS. 8a and 8b illustrate the polishing, sand blasting, and surface finishing of the product surface according to an embodiment of the present invention;

fig. 9a-9c show the housing structure of the product according to the embodiment of the invention, and the product is subjected to secondary CNC high-light chamfering and secondary anodizing treatment according to the appearance of the product or the process requirements.

Detailed Description

The embodiments of the present invention will be described in detail below. It should be emphasized that the following description is merely exemplary in nature and is not intended to limit the scope of the invention or its application.

Referring to fig. 1 to 9C, in an embodiment, a 3C electronic product casing includes a metal structure member 1, a plurality of antenna splitting micro-gaps 4 are formed between a back surface 102 and a front surface 101 of the metal structure member 1 in a penetrating manner, the antenna splitting micro-gaps 4 are filled with a non-conductive pre-injection molding material 3, a plastic structure 2 formed by secondary injection molding is arranged on the back surface of the metal structure member 1, and the plastic structure 2, the pre-injection molding material 3 and the metal structure member 1 are combined into a whole.

In a preferred embodiment, the width of the antenna sub-positioning slit 4 is 0.03mm to 0.8 mm.

In a preferred embodiment, the spacing distance between the antenna-dividing positioning micro-slits 4 is more than 0.15 mm.

In a preferred embodiment, an anodized layer formed by anodization is formed on a metal surface of the front surface of the metal structural member 1 except for the area of the antenna splitting micro-slit 4, and preferably, the pre-injection material 3 is a material having a color similar to or the same as that of the anodized layer, and may also be a white or black material, etc.

In a preferred embodiment, the front surface of the metal structural member 1 is entirely covered with an anodic oxide film or anodic-like oxide film 5 formed by thermal transfer printing, and preferably, a primer layer is provided between the front surface of the metal structural member 1 and the anodic oxide film or anodic-like oxide film.

In a preferred embodiment, the front surface of the metal structural member 1 is integrally plated with an aluminum film layer on which an anodized layer formed by anodization is formed, and a primer layer is preferably provided between the front surface of the metal structural member 1 and the aluminum film layer.

Referring to fig. 1 to 9C, in a metal blank for manufacturing a 3C electronic product casing, glue running holes 6 extending between a back surface 102 and a front surface 101 of the metal blank are formed in positions, corresponding to antenna sub-positioning micro-slits 4, of the back surface 102 of the metal blank, and the antenna sub-positioning micro-slits 4 are formed in the metal blank and then communicated with the glue running holes 6 so as to perform pre-injection molding on the antenna sub-positioning micro-slits 4. In a preferred embodiment, the deepest part of the glue hole 6 is more than 0.2mm away from the front surface of the metal blank.

Referring to fig. 1 to 9C, a method for manufacturing a housing of a 3C electronic product includes the following steps:

processing a penetrating antenna splitting positioning micro-seam 4 between the back surface 102 and the front surface 101 of the metal blank, preferably processing by adopting a laser cutting or laser etching process or a CNC process;

pre-injection molding is carried out on the antenna sub-position micro-gap 4 by using a non-conductive pre-injection molding material, and the antenna sub-position micro-gap is filled;

and performing secondary injection molding on the back surface of the metal blank to form a plastic structure, wherein the plastic structure 2 and the pre-injection molding material 3 are integrally combined together with a set strength and are combined with the metal blank.

In a preferred embodiment, the metal blank is provided with a reinforcing structure 7 to prevent the metal area cut off during the antenna cutting position micro-seam processing from deforming or separating and falling off; the reinforcing structure 7 is removed before the second injection molding.

In a preferred embodiment, before the pre-injection molding is carried out, glue running holes which can be connected with the antenna sub-positioning micro-slits and penetrate through the metal blank but do not penetrate through the metal blank are machined on the back surface of the metal blank; before secondary injection molding, processing and removing the part with the glue running hole on the back surface of the metal blank to expose the antenna sub-parting micro-seam; and the glue running hole is processed before the antenna splitting position micro-seam is processed, or is processed after the antenna splitting position micro-seam is processed.

In a preferred embodiment, after the second injection molding, the method further comprises the steps of:

forming an anodic oxidation layer on the metal surface of the front surface of the metal structural part except for the area of the antenna splitting position micro-slit by an anodic oxidation process, wherein the pre-injection material is a material with a color similar to or the same as that of the anodic oxidation layer, or a white or black material; or

Features and advantages of embodiments of the present invention are described further below with reference to the accompanying drawings.

Fig. 1a to 1b show a rough blank of a metal structural member and undergo CNC preprocessing, and the material of the rough blank is a metal material, such as aluminum alloy, stainless steel, magnesium alloy, titanium alloy, and the like. According to the product structure, the metal rough blank can be realized by selecting proper section stamping, aluminum extrusion, die casting, casting and other processing technologies, and the embodiment is realized by an aluminum extrusion technology.

The metal blank may be provided with a process reference surface, a fixing structure or a screw hole, a process positioning hole or structure, for example a positioning hole with a diameter of about 4mm, for subsequent injection molding or CNC machining. On the side surface or the bottom surface of the rough blank, a reinforcing rib structure for connecting the micro-seam and the metal product main body is processed in advance, so that the metal area cut by the micro-seam in the subsequent processing is prevented from deforming or falling off (in the example, the product bottom surface is thickened).

On the back of the metal rough blank (corresponding to the inner side of the product) to be processed with the antenna micro-seam, a glue-passing hole which can be connected with the micro-seam and can pass through but can not pass through the metal rough blank is processed in advance, and the glue-passing hole can be beneficial to the effect of the non-conductive pre-injection molding material on filling and exhausting the micro-seam and enhancing the aluminum-plastic bonding force. The glue walking holes are formed in the back face of the metal rough blank, and the deepest positions of the glue walking holes are preferably more than 0.2mm away from the front face of the metal rough blank.

According to the requirements of products and processes, a proper glue drawing structure can be added on the surface of the metal rough blank so as to increase the bonding force of metal and non-conductive pre-injection molding material in the micro-seam area and prevent the non-conductive pre-injection molding material from cracking and falling off in the processing process.

According to the process requirements, a supporting and reinforcing structure or thickness preprocessing can be carried out on the back area of the metal rough blank to be processed with the antenna micro-seam, and the post-processing allowance is reduced, so that the problems of cracking, deformation, size fluctuation and the like in the post-processing of filling the micro-seam with the non-conductive pre-injection molding material can be controlled. The supporting reinforcing structure or the reserved thickness can be processed according to the process requirements, so that the supporting effect is achieved, and the problems of deformation, cracking or size over-tolerance in the processes of micro-seam processing, micro-seam injection molding and post-process processing are solved.

According to the process requirements, the part with the precision requirement on the metal rough blank can be subjected to finish machining.

Fig. 2a to 2c illustrate the antenna micro-seam processing on the metal structure by using laser cutting, laser etching, wire cutting, and CNC processes, wherein the micro-seam penetrates through the antenna cutting position of the product.

Preferably, the width of the antenna dividing position micro-seam on the appearance surface after the micro-seam processing is generally 0.03 mm-0.8 mm, and the antenna dividing position micro-seam penetrates through the antenna dividing position area on the product, so that an antenna signal can conveniently pass through the metal shell. The minimum spacing between the antenna micro-slots is not less than 0.15 mm. The number of the antenna micro-slits can be 1-6 pieces respectively on the upper and lower parts or in the middle of the metal shell according to antenna signals or product requirements, and the structure is not limited. The antenna micro-slot can be shaped to pass through the antenna signal, and the structure is not limited to be a straight line, an arc line, a curve or other shapes.

Fig. 3a to 3b show a surface treatment of a metallic structural member after micro-crack processing and a first injection molding of the micro-crack region to fill the micro-crack with a non-conductive pre-injection molding material.

Before injection molding, the metal structure may be subjected to surface nano-treatment, passivation treatment or other surface treatment that enhances the bond strength of the non-conductive pre-injection molded material to the metal, depending on the process requirements.

After injection molding, the product can be subjected to aging treatment for enhancing the bonding strength of the injection molding material and the metal and eliminating stress according to the process requirements, and the baking temperature and time are required to be carried out according to the injection molding material and the injection molding process requirements.

Fig. 4a to 4b illustrate CNC machining of the region to be provided with the plastic structure on the metal structural member after the first injection molding.

And performing CNC (computer numerical control) finish machining on the area to be provided with the plastic structure and the area with the requirement on dimensional accuracy on the metal structural part so as to perform secondary injection molding on the plastic structure of the product.

According to the requirements of products and processes, the metal pulling glue position can be processed on the area with weak bonding strength of metal and plastic cement, so that the integral strength of the product is ensured, and the problem of deformation or cracking is prevented.

Fig. 5a to 5b show a metal structural part of a product subjected to a surface treatment and a second injection molding to form a plastic structure in the product.

Before injection molding, the metal structural part is subjected to surface nano treatment, passivation treatment or other surface treatment capable of enhancing the bonding strength of plastic and metal according to the process requirements.

The material of moulding plastics for the first time and the material of moulding plastics for the second time have good bonding strength, and layering or the problem of droing do not appear, avoid reducing the bonding strength of antenna cutting position region.

After injection molding, the product can be subjected to aging treatment for enhancing the bonding strength of plastic and metal and eliminating stress according to the process requirements, and the baking temperature and time are required to be carried out according to the plastic material and the injection molding process requirements.

Fig. 6a to 6b are the front CNC fine machining and the CNC machining of the side holes of the functional structure, such as the camera, the key, the power key, etc., of the product after the second injection molding is completed, and the front allowance of the product is removed.

Fig. 7a to 7b are views showing the finishing of the area of the product having the assembly and dimensional accuracy requirements on the back side and the separation of the product from the excess metal blank.

Fig. 8a to 8b are the surface of the product is polished and sand blasted, and then surface decoration treatment is carried out, and according to different product requirements, various surface treatment schemes can be adopted:

the first scheme is as follows: after polishing and sand blasting are carried out on the product, anodic oxidation treatment is carried out on the surface of the metal part of the product, so that an appearance surface which is integrally consistent or approximately consistent is generated on the surface of the product, the visibility of the antenna cutting position on the metal shell of the communication electronic product is eliminated, and the appearance effect that the appearance is consistent and unified is realized.

Scheme II: the spraying process is used for spraying a layer of primer on the surface of the product and filling the primer on the surface of each structure part of the product, so that the defects of gaps, steps and the like between the structure connecting parts of the product are further eliminated, the surface of the product generates an integrally consistent appearance surface, and the binding force between the thermal transfer printing anodic oxide film or similar anodic oxide film and each product structure in the post-process is enhanced. Then, the appearance surface of the product is coated with a layer of non-conductive anodic oxide film or anodic oxide-like film by using the heat transfer printing procedures of heating, pre-stretching, pressure forming, cooling and the like, thereby thoroughly eliminating the visibility of the antenna cutting position on the metal shell of the communication electronic product and realizing the appearance effect of anodic oxidation with consistent appearance and integral unity.

The third scheme is as follows: according to different processes of metal and injection molding materials and matching, a primer layer is sprayed or plated on the surface of the product to cover and fill the surface of each structure part of the product, so that the defects of gaps, steps and the like among the structure connecting parts of the product are further eliminated, and the surface of the product generates an overall uniform appearance surface. Then plating an aluminum film layer on the appearance surface of the product, and then carrying out an anodic oxidation process to form an anodic oxidation layer on the aluminum film layer, wherein the thickness of the anodic oxidation layer is based on that the aluminum film layer is not conductive. Preferably, the thickness of the aluminum film layer is 0.07 mm-0.35 mm.

As shown in fig. 9a to 9c, finally, according to the appearance of the product or the process requirement, the product can be selectively subjected to the secondary CNC high-light chamfering and the secondary anodizing to meet the product requirement.

As shown in fig. 9a to 9c, six micro-slits of 0.15mm may be provided at the front and rear ends of the housing, or three micro-slits of 0.4mm may be provided at the front and rear ends of the housing.

The traditional one-time injection molding process can realize direct injection molding of a 1.2mm groove structure, has binding force, is not trapped in air, is not deformed, cannot perform injection molding of a micro-seam with the width of 0.4mm or less, can generate injection molding defects of deformation of an antenna cutting position, air trapping, glue shortage, no binding strength and the like, and cannot realize mass production.

The preferred embodiment of the invention employs the following process: 1. firstly, strengthening the structure of the back of the micro-seam area; 2. processing the gap of the micro-gap area; 3. firstly, independently carrying out first-time micro-seam injection molding on a micro-seam area; 4. CNC removes the back reinforcing support structure, and then carries out the second plastic structure injection molding.

Through a first pre-injection molding process, the antenna micro-gap area is specially filled, the strength of the micro-gap area is enhanced, and then the second injection molding is carried out, so that the micro-gap filling and the injection molding with binding force which can be completely filled with injection molding materials are realized.

The traditional process can not realize the centralized processing of three or six antenna grooves, and the traditional process has the defects that the quality of an antenna cutting position is unqualified and the actual mass production performance is not caused due to the problems of distortion (weak metal strength caused by narrow space of the antenna cutting position), deformation, inconsistent gaps after processing, over-poor size, caking or blockage of metal residues and the like caused by air pressure, water pressure and processing stress in the process of laser, CNC and wire cutting processing because the three or six antenna grooves are densely distributed together.

In the preferred embodiment of the invention, the structural reinforcement is realized by designing a supporting structure on the back of the micro-seam processing area or increasing the thickness allowance, so that the metal slitting positions are ensured not to deform.

Preferably, before the first injection molding is performed on the micro-seam area, the micro-seam injection molding glue-walking holes are processed on the back of the product, so that the glue-walking holes are increased, and the following advantages can be obtained: 1. the filling of the micro-gap by the non-conductive pre-injection molding material is facilitated; 2. the excessive gas is discharged, the gas trapping is avoided, and meanwhile, the metal residues in the micro-seam processing can be smoothly discharged; 3. the glue running time of the micro-seam area is shortened, and the bonding strength of the aluminum alloy and the non-conductive pre-injection molding material is increased; 4. the injection molding pressure of the micro-gap area is reduced, and the problems of bending, deformation and size over-tolerance of the antenna micro-gap structure caused by insufficient metal strength when the non-conductive pre-injection molding material is filled in the dense and weak-strength antenna micro-gap structure area under high pressure are solved.

The foregoing is a more detailed description of the invention in connection with specific/preferred embodiments and is not intended to limit the practice of the invention to those descriptions. It will be apparent to those skilled in the art that various substitutions and modifications can be made to the described embodiments without departing from the spirit of the invention, and these substitutions and modifications should be considered to fall within the scope of the invention.

Claims

1. A metal blank for manufacturing a 3C electronic product shell is characterized in that a glue running hole extending between the back surface and the front surface of the metal blank is formed in a part to be machined and removed, corresponding to the position of an antenna splitting position micro-seam, on the back surface of the metal blank, the antenna splitting position micro-seam is communicated with the glue running hole after being formed on the metal blank so as to perform pre-injection molding on the antenna splitting position micro-seam, and before performing secondary injection molding on the back surface of the metal blank, the part, provided with the glue running hole, on the back surface of the metal blank is machined and removed so as to expose the antenna splitting position micro-seam; preferably, the deepest part of the glue hole is more than 0.2mm away from the front surface of the metal blank.

2. A preparation method for preparing a 3C electronic product shell is characterized by comprising the following steps:

preferably, the metal blank is provided with a reinforcing structure to prevent the metal area cut off during the antenna slitting position micro-seam processing from deforming or separating and falling off; removing the reinforcing structure before performing the secondary injection molding;

before the pre-injection molding is carried out, glue running holes which can be connected with the antenna sub-positioning micro-slits and penetrate through the metal blank but do not penetrate through the metal blank are machined on the part to be machined and removed on the back surface of the metal blank; before secondary injection molding, processing and removing the part with the glue running hole on the back surface of the metal blank to expose the antenna sub-parting micro-seam; and the glue running hole is processed before the antenna splitting position micro-seam is processed, or is processed after the antenna splitting position micro-seam is processed.

3. The method of claim 2, further comprising the step of, after the second injection molding: