Production process of three-proofing mobile phone battery cover

Abstract

The invention relates to a production process of a three-proofing mobile phone battery cover, and belongs to the technical field of mobile phone part production and manufacturing. Comprising the following steps: S1, injection molding of a shell body; s2, calculating the shrinkage rate; s3, designing a polycarbonate mold; s4, shell sealing ring LSR injection molding is conducted; s5, designing a TPU rubber coating mold; and S6, TPU (thermoplastic polyurethane) encapsulation. The invention provides a production process of a three-proofing mobile phone battery cover, which is used for solving the technical problems of insufficient adhesive coating binding force and leakage risk in the prior art.

Description

Technical Field

[0001] The invention belongs to the technical field of production and manufacturing of mobile phone parts, and in particular relates to a production process of a triple-proof mobile phone battery cover. Background Art

[0002] The triple-proof mobile phone has the functions of dustproof, shockproof and waterproof. It can adapt to various harsh environments. It has a wide range of applications in many fields and shows good development prospects.

[0003] For drop resistance, the body and battery cover themselves need to have high rigidity and toughness to ensure strong strength. At the same time, the outer surface needs to be made of soft glue such as TPU two-color molding or rubber coating to achieve the purpose of drop resistance, and then the waterproof performance is designed based on this process; usually, three-proof mobile phones use strict waterproof sealing design and high-level waterproof materials to achieve the purpose of waterproof. For example, some three-proof mobile phones are tested and certified based on the international protection level standard IP68, which means that the mobile phone can be immersed in an environment of 1.2 meters deep for 30 minutes without damage. However, in order to ensure the beauty and thin design of the product, the battery area cannot be designed to be too thick and have too many hooks and screws. Therefore, in the case of limited space, most of them use thinner sealing rings or waterproof glue structures, and use rubber rings to achieve sealing through interference fit on the battery cover.

[0004] The patent with announcement number CN111497122A discloses a pre-deformation process of injection molding and overmolding of a metal middle frame, which includes the following steps: step one: die casting; step two: chemical passivation; step three: laser etching; step four: product deformation reverse simulation design; step five: mold profiling design; step six: pre-deformation injection molding and overmolding.

[0005] In the implementation process of the existing technology, there are at least the following problems:

[0006] In the production process of the prior art, since the density of polycarbonate plus glass fiber material is relatively high, fibers are easily floated on the surface, resulting in insufficient bonding strength and the risk of leakage. Summary of the invention

[0007] The invention provides a production process for a triple-proof mobile phone battery cover, which is used to solve the technical problems in the prior art of insufficient adhesive bonding and leakage risk.

[0008] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0009] A production process for a triple-proof mobile phone battery cover comprises the following steps:

[0010] S1, shell body injection molding, a shell body made of polycarbonate and glass fiber is injection molded through a mold;

[0011] S2. Calculation of shrinkage rate: The flow direction and overall shrinkage of the plastic fluid in the mold cavity are simulated by CAE software. Combined with the temperature curve of the LSR injection process, the physical shrinkage rate a1 of the polycarbonate added glass fiber material is determined. After high-temperature baking by the LSR process, the post-shrinkage rate a2 of the body in the mold cavity of the overmolding mold is determined. Add the pre-compression value b1 required for the third shot TPU overmolding, and finally determine the total shrinkage rate a3 of the shell;

[0012] S3, polycarbonate mold design, according to the above-obtained shrinkage rate a3, design a mold to support the polycarbonate body, so that the outer dimensions of the shell produced meet the requirements of the second injection mold, so as to facilitate the subsequent LSR process;

[0013] S4, LSR injection molding of the housing seal ring, the polycarbonate body obtained by the first shot is subjected to plasma treatment to increase the surface tension of the polycarbonate after adding glass fiber material, and then the body is placed in a silicone mold after high temperature treatment, and the silicone is directly injected and combined with the body by a liquid silicone injection machine to form a sealing strip with stable shape and size;

[0014] S5. Design of TPU overmolding mold. In the design of TPU overmolding mold, an undercut fixing groove is designed according to the shape of silicone sealing ring. The undercut fixing groove is used to adsorb the shell on the mold during the third shot. At the same time, the elasticity of silicone is used to guide the shell and keep it in a suitable position at the moment of mold closing.

[0015] S6, TPU encapsulation, put the shell with LSR injection molding seal ring into the designed TPU encapsulation mold, carry out TPU encapsulation, through secondary compression during encapsulation and inspection of the firmness of LSR process, finally obtain the triple-proof mobile phone battery cover product.

[0016] Furthermore, in the step S2, pre-pressure is provided to the sealing area during the encapsulation process to ensure a thickness margin of 0.1mm-0.2mm on one side of the shell, and a shrinkage rate of 0.1% is added when the shell is shot.

[0017] Furthermore, in the step S4, the polycarbonate body of the first shot is subjected to plasma treatment to improve the reliability of the bonding force between the silicone and the polycarbonate.

[0018] Furthermore, 10% of glass fiber is added to the polycarbonate in step S1.

[0019] Furthermore, in step S2, the temperature curve of the LSR injection process is combined to determine the physical shrinkage rate a1 of the polycarbonate plus 10% glass fiber material, the post-shrinkage rate a2 of the body in the overmolding mold cavity caused by the high-temperature baking of the LSR process for 90 seconds, and the pre-compression value b1 required for the third shot TPU overmolding, and finally the total shrinkage rate a3=a1+a2+b1 of the shell is determined.

[0020] Furthermore, in the step S4, the surface tension of the rubber-encapsulated area is ≥51 dyn.

[0021] The present invention provides a production process for a triple-proof mobile phone battery cover, and the beneficial effects are:

[0022] Plasma treatment of the first shot polycarbonate body is used to solve the problem of high density of polycarbonate plus glass fiber material and easy fiber floating on the surface, which leads to poor bonding during encapsulation, thereby making the bonding between silicone and polycarbonate firm and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 This is a line chart of the shrinkage rate of the material at different temperatures when the LSR process is baked at high temperature for 90 seconds;

[0025] Figure 2 A production process flow chart of a triple-proof mobile phone battery cover provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0026] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0027] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0028] 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. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0029] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be welding, bolt connection, or riveting; it can be fixed connection, detachable connection, or integral connection; it can be mechanical connection or electrical connection; it can be directly connected or indirectly connected through an intermediate medium, or it can be internal communication between two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0030] Example:

[0031] This embodiment provides a production process for a triple-proof mobile phone battery cover, comprising the following steps:

[0032] S1, shell body injection molding, a shell body made of polycarbonate and glass fiber is injection molded through a mold;

[0033] S2. Calculation of shrinkage rate: The flow direction and overall shrinkage of the plastic fluid in the mold cavity are simulated by CAE software. Combined with the temperature curve of the LSR injection process, the physical shrinkage rate a1 of the polycarbonate added glass fiber material is determined. After high-temperature baking by the LSR process, the post-shrinkage rate a2 of the body in the mold cavity of the overmolding mold is determined. Add the pre-compression value b1 required for the third shot TPU overmolding, and finally determine the total shrinkage rate a3 of the shell;

[0034] S3, polycarbonate mold design, according to the above-obtained shrinkage rate a3, design a mold to support the polycarbonate body, so that the outer dimensions of the shell produced meet the requirements of the second injection mold, so as to facilitate the subsequent LSR process;

[0035] S4, LSR injection molding of the housing seal ring, the polycarbonate body obtained by the first shot is subjected to plasma treatment to increase the surface tension of the polycarbonate after adding glass fiber material, and then the body is placed in a silicone mold after high temperature treatment, and the silicone is directly injected and combined with the body by a liquid silicone injection machine to form a sealing strip with stable shape and size;

[0036] S5. Design of TPU overmolding mold. In the design of TPU overmolding mold, an undercut fixing groove is designed according to the shape of silicone sealing ring. The undercut fixing groove is used to adsorb the shell on the mold during the third shot. At the same time, the elasticity of silicone is used to guide the shell and keep it in a suitable position at the moment of mold closing.

[0037] S6, TPU encapsulation, put the shell with LSR injection molding seal ring into the designed TPU encapsulation mold, carry out TPU encapsulation, through secondary compression during encapsulation and inspection of the firmness of LSR process, finally obtain the triple-proof mobile phone battery cover product.

[0038] In this embodiment, if Figure 2 As shown in the flow chart, the first shot polycarbonate body is subjected to plasma treatment to solve the problem of high density of polycarbonate plus glass fiber material and easy floating fibers on the surface, which leads to poor bonding during encapsulation, thereby making the bonding between silicone and polycarbonate firm and reliable; by involving undercut fixing grooves on the TPU encapsulation mold, the shell body is prevented from falling or moving during the TPU encapsulation process, resulting in crushing and scrapping of the product, and the elasticity and certain strength of silicone are used to achieve positioning and protection of the shell; after plasma treatment, the surface tension of the shell is increased, which improves the bonding strength of LSR.

[0039] Furthermore, in some implementations of the present embodiment, in step S2, it is also necessary to combine the good fluidity of TPU and its overflow value of 0.015, as well as the sufficient pre-compression required for the sealing area during the encapsulation process, and a pre-compression requirement of 0.1-0.2mm on one side of the shell side is required. According to the existing product size, a shrinkage rate of 0.1% is calculated when the shell is shot.

[0040] In this embodiment, the stress condition of the sealing area during the encapsulation process is simulated, and the pre-pressure required for the sealing area under the premise of ensuring a good sealing effect is analyzed according to different product structures and sizes. At the same time, through actual production tests, the sealing performance of products under different pre-pressure values ​​is tested, including airtightness testing and watertightness testing, to determine that the pre-pressure requirement of 0.1-0.2mm on one side of the shell side can meet the sealing requirements of the product.

[0041] Furthermore, in some implementations of this embodiment, in step S4, the polycarbonate body of the first shot is subjected to plasma treatment to improve the reliability of the bonding force between the silicone and the polycarbonate.

[0042] In this embodiment, the surface tension of the shell is increased after plasma treatment through the technical process, so that the bonding strength of LSR is increased by 500%, and no defects are produced, which significantly improves the leakage risk of the entire product.

[0043] Furthermore, in some implementations of this embodiment, 10% of glass fiber is added to the polycarbonate in step S1.

[0044] In this embodiment, 10% glass fiber is added to the matrix material to improve the strength, rigidity and deformation resistance of the material, and the structural performance is improved without affecting the fluidity and formability of the material.

[0045] Furthermore, in some implementations of the present embodiment, in step S2, combined with the temperature curve of the LSR injection process, it is determined that the physical shrinkage rate a1 of the polycarbonate plus 10% glass fiber material is 0.5%, and the high-temperature baking of the LSR process for 90 seconds makes the post-shrinkage rate a2 of the main body in the overmolding mold cavity be 0.1%. The pre-compression value b1 required for the third shot TPU overmolding is 0.1%, and finally the total shrinkage rate a3 of the shell is determined to be 0.7%.

[0046] In this embodiment, if Figure 1 As shown, by combining the required shrinkage rates of the three injections, the shrinkage rate of the polycarbonate material in the first shot is finally set to 0.5%+0.1%+0.1%=0.7%, and the mold design is carried out based on this.

[0047] Furthermore, in some implementations of this embodiment, the surface tension of the rubber-encapsulated area in step S4 is ≥51 dyn.

[0048] In this embodiment, in order to increase the surface tension of the polycarbonate material with 10% glass fiber and enhance the coating force and reliability of the silicone and polycarbonate materials, a plasma treatment is performed on the area of ​​the polycarbonate material that needs to be coated with silicone to increase its surface tension to ≥51.

[0049] In summary, the process has changed from the previous process of producing parts with multiple materials and multiple times, which required turnover and transportation to complete, to only two times of encapsulation, which improves the efficiency and convenience of production and saves more than 40% of time cost; the surface tension of the shell is improved after plasma treatment, which increases the bonding force of LSR by 500%, and no defects are produced, which significantly improves the leakage risk of the entire product; there is no need to manufacture multiple sets of molds and place them in different places to complete production, which saves more than 20% of mold costs, and silicone does not need to be vulcanized and removed, and the production efficiency is increased from the previous 240S / set to 160S / set, which is more than 30% higher efficiency;

[0050] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope of the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A production process for a triple-proof mobile phone battery cover, characterized in that: The following steps are involved: S1, shell body injection molding, a shell body made of polycarbonate and glass fiber is injection molded through a mold; S2. Calculation of shrinkage rate: The flow direction and overall shrinkage of the plastic fluid in the mold cavity are simulated by CAE software. Combined with the temperature curve of the LSR injection process, the physical shrinkage rate a1 of the polycarbonate added glass fiber material is determined. After high-temperature baking by the LSR process, the post-shrinkage rate a2 of the body in the mold cavity of the overmolding mold is determined. Add the pre-compression value b1 required for the third shot TPU overmolding, and finally determine the total shrinkage rate a3 of the shell; S3, polycarbonate mold design, according to the obtained shrinkage rate a3, design a mold to support the polycarbonate body so that the outer dimensions of the shell produced meet the requirements of the second injection mold, so as to facilitate the subsequent LSR process; S4, LSR injection molding of the housing seal ring, the polycarbonate body obtained by the first shot is subjected to plasma treatment to increase the surface tension of the polycarbonate after adding glass fiber material, and then the body is placed in a silicone mold after high temperature treatment, and the silicone is directly injected and combined with the body by a liquid silicone injection machine to form a sealing strip with stable shape and size; S5. Design of TPU overmolding mold. In the design of TPU overmolding mold, an undercut fixing groove is designed according to the shape of silicone sealing ring. The undercut fixing groove is used to adsorb the shell on the mold during the third shot. At the same time, the elasticity of silicone is used to guide the shell and keep it in a suitable position at the moment of mold closing. S6, TPU encapsulation, put the shell with LSR injection molding seal ring into the designed TPU encapsulation mold, carry out TPU encapsulation, through secondary compression during encapsulation and inspection of the firmness of LSR process, finally obtain the triple-proof mobile phone battery cover product.

2. The production process of a triple-proof mobile phone battery cover according to claim 1, characterized in that: In the step S2, pre-pressure is provided to the sealing area during the encapsulation process to ensure a thickness margin of 0.1mm-0.2mm on one side of the shell, and a shrinkage rate of 0.1% is added when the shell is shot.

3. The production process of a triple-proof mobile phone battery cover according to claim 1, characterized in that: In the step S4, the first shot polycarbonate body is subjected to plasma treatment to improve the reliability of the bonding force between the silicone and the polycarbonate.

4. According to the production process of a triple-proof mobile phone battery cover according to claim 1, 10% of glass fiber is added to the polycarbonate in the step S1.

5. The production process of a triple-proof mobile phone battery cover according to claim 1, characterized in that: In step S2, the temperature curve of the LSR injection process is combined to determine the physical shrinkage rate a1 of the polycarbonate plus 10% glass fiber material, the post-shrinkage rate a2 of the body in the overmolding mold cavity caused by the high-temperature baking of the LSR process for 90 seconds, and the pre-compression value b1 required for the third shot TPU overmolding, and finally determine the total shrinkage rate a3=a1+a2+b1 of the shell.

6. The production process of a triple-proof mobile phone battery cover according to claim 1, characterized in that: In the step S4, the surface tension of the rubber-encapsulated area is ≥51 dyn.

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