CN110802795A

CN110802795A - Shell integrally-formed preparation method and shell

Info

Publication number: CN110802795A
Application number: CN201910957071.3A
Authority: CN
Inventors: 陈卓耿; 黄日杨; 许万; 许仁; 王伟
Original assignee: Wanjin Technology Co Ltd; Maxford Technology Ltd
Current assignee: Wanjin Technology Co Ltd; Maxford Technology Ltd
Priority date: 2019-10-10
Filing date: 2019-10-10
Publication date: 2020-02-18

Abstract

The invention discloses a shell integrally-formed preparation method and a shell. The preparation method comprises the following steps: adopting a UV transfer printing process to transfer printing UV grains on the plastic sheet to obtain a transfer printing sheet; performing PVD coating on the UV lines to form a PVD film layer to obtain a coated sheet; performing silk-screen printing on the PVD film layer to obtain a silk-screen sheet; covering high-temperature-resistant protective films on two sides of the silk-screen sheet to obtain a film-covered sheet; cutting the laminated sheet according to a preset size to obtain a cut sheet; carrying out high-pressure forming on the cut sheet to obtain a semi-finished product with an inner buckle structure; and carrying out CNC (computerized numerical control) processing on the semi-finished product to obtain the 3D forming sheet. The preparation method can realize the integration of the middle frame on the sheet, improve the design freedom of the product and the integration degree of the terminal product, and can perform surface decoration before the product is formed, so that the product has lines and a dazzling effect, the film sticking process is reduced, and the processing cost is reduced.

Description

Shell integrally-formed preparation method and shell

Technical Field

The invention relates to the field of injection molding, in particular to a shell integrally-formed preparation method and a shell.

Background

In the 5G era, the non-metal back cover of the mobile phone is mainly made of glass, plastic and ceramic, wherein the glass (2.5D/3D) and the ceramic are mainly applied to medium-high-end models, and the plastic is the first choice for the rear cover of the medium-low-end model with high cost performance, and is deeply valued by the vast mobile phone terminals. According to the forecast of the industry, the market share of the plastic shell mobile phone in 2019 can reach 70%, and the plastic shell industry is the most important. At present, a plastic shell mainly comprises two processes of a composite plate and injection molding of imitation glass, wherein the composite plate is used as a scheme of an imitation glass mobile phone back cover, and benefits from the high cost performance of the composite plate relative to glass, rich and flexible customizable appearance, simpler process flow, fast climbing and mass production of various models such as three stars, Huacheng, OPPO and vivo. The two fields of new materials and new processes are different day by day, the change is more and more intense, particularly in the evolution process of demetallizing the mobile phone shell, the plastic shell is gorgeously upgraded by virtue of a 3D glass imitation process, and the middle frame integrated machine body is more distinctive, namely the integrally formed machine body. At present, the mainstream forming process of the glass-imitated rear cover in the market is a composite board high-pressure forming process and a PC injection molding process. The high-pressure forming process has the advantages that the machine type of the existing mass production is limited to the simple 3D rear cover, the radian is gentle, the radian is low, an integrated machine body cannot be formed, the rear cover part can only be completed, a middle frame needs to be added to the whole machine, the cost of the middle frame is increased, and the integrated hand feeling of the whole machine is influenced. Although the injection molding process is applied to a small number of models in mass production, the injection molding process cannot perform grain decoration per se, only can rely on film pasting for decoration, has great limitation, and is immature in an integrated injection molding process and cannot perform in-mold decoration.

Disclosure of Invention

Therefore, it is necessary to provide a method for integrally manufacturing a housing, which can realize the center-integrated body structure on a sheet, improve the design freedom of a product, improve the integration degree of a terminal product, perform surface decoration before product molding to make the product have lines and a glare effect, reduce a film attaching process, and reduce the processing cost, and a housing.

A shell integrally-formed preparation method comprises the following steps:

(1) transferring UV lines on the plastic sheet to obtain a transfer sheet;

(2) performing PVD coating on the UV lines to form a PVD film layer to obtain a coated sheet;

(3) performing silk-screen printing on the PVD film layer to obtain a silk-screen sheet;

(4) covering high-temperature-resistant protective films on two sides of the silk-screen sheet to obtain a film-covered sheet;

(5) cutting the film-covered sheet according to a preset size to obtain a cut sheet;

(6) carrying out high-pressure forming on the cut sheet to obtain a semi-finished product with an inner buckle structure;

(7) and carrying out CNC (computer numerical control) processing on the semi-finished product to obtain a 3D forming sheet.

In one embodiment, the thickness of the plastic sheet in step (1) is between 0.5mm and 2.0 mm.

In one embodiment, the plastic sheet in step (1) is a plastic sheet prepared from PC, PMMA or a composite material of PC and PMMA.

In one embodiment, the thickness of the UV lines in step (1) is between 3 μm and 30 μm.

In one embodiment, the thickness of the ink during silk-screening in the step (3) is between 5 μm and 50 μm.

In one embodiment, the height of the semi-finished product in the step (6) is between 4mm and 8 mm.

In one embodiment, the CNC processing in step (7) is to remove an unnecessary skirt portion of the semi-finished product, and the height of the 3D shaped sheet after the CNC processing is between 3-7 mm.

In one embodiment, the cut sheet is high-pressure formed in step (6) by a preset die comprising: a lower die, a second upper die and a second upper die, wherein the upper surface of the lower die is provided with a forming groove, the inner side wall of the forming groove is curved, the first upper pressing die is provided with a first boss, the outward side surface of the first boss is curved and is sunken, the second upper pressing die is provided with a second boss, the outward side surface of the second boss is in a shape of an inwards sunken curved surface, the first boss and the second boss can enclose an annular matching boss, a matching groove is formed in the area between the first upper pressing die and the second upper pressing die and below the matching boss, the matching groove can be matched with the lower pressing die, the matching lug boss is in contact matching with the upper surface of the lower pressing die when the first upper pressing die and the second upper pressing die are arranged around the lower pressing die, the side surface of the first boss, the side surface of the second boss and the inner wall of the forming groove form an arc-shaped surface for obtaining the inner buckle structure.

In one embodiment, the high pressure forming process parameters in step (6) include: the heating temperature is 200-400 ℃, the heating time is 40-100 s, the forming blowing pressure is 30-60 Kgf, the pressure maintaining time is 1-60 s, and the mold temperature of the preset mold is 100-150 ℃.

In one embodiment, the method further comprises the step (8) of hardening and UV curing the 3D forming sheet to obtain the shell.

The shell is prepared by the shell integral forming preparation method.

The shell integrally-formed preparation method has the following beneficial effects:

(1) compared with the traditional high-pressure process, the invention realizes the integrated molding structure of the middle frame and the back shell on the plastic sheet, greatly improves the design freedom of the product and improves the integration degree of the terminal product.

(2) Compared with the traditional injection molding process, the invention can carry out surface decoration before the product is molded, so that the product has lines and a dazzling effect, the film sticking process is reduced, and the processing cost is greatly reduced.

(3) The equipment adopted by the invention is simple, is generally used for a high-pressure forming machine for a simple 3D plastic rear cover finished product, does not need additional newly-purchased equipment for a 3D plastic rear cover processing manufacturer, and has low production equipment requirement and low cost.

Drawings

Fig. 1 is a schematic view of a predetermined mold according to an embodiment of the present invention;

FIG. 2 is a schematic top view of the pre-mold shown in FIG. 1 after the first upper mold and the second upper mold are engaged;

FIG. 3 is a schematic view of the pre-mold shown in FIG. 1 during processing of the semi-finished product;

FIG. 4 is a schematic view of a semi-finished product;

fig. 5 is a schematic view of a 3D formed sheet.

Description of the reference numerals

20: presetting a mold; 201: pressing a die; 2011: forming a groove; 202: a first upper die; 2021: a first boss; 203: a second lower die; 2031: a second boss; 204: matching with the boss; (ii) a 205: a yielding groove; 206: an arc-shaped surface; 31: semi-finished products; 32: 3D forming a sheet; 321: an inner buckle structure.

Detailed Description

To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

An embodiment of the invention provides a shell integrally-formed preparation method, which comprises the following steps:

(1) taking a plastic sheet, wherein the thickness of the plastic sheet is between 0.5mm and 2.0 mm. The plastic sheet is made of PC, PMMA or a PC and PMMA composite material. And (3) adopting a UV transfer printing process to transfer UV grains on the plastic sheet to obtain a transfer printing sheet, wherein the thickness of the UV grains is between 3 and 30 micrometers.

(2) And performing PVD coating on the UV lines to form a PVD film layer to obtain a coated sheet.

(3) Performing silk-screen printing on the PVD film layer to obtain a silk-screen sheet; the thickness of the printing ink is between 5 and 50 mu m during silk-screen printing.

(4) And covering high-temperature-resistant protective films on two sides of the silk screen printing sheet to obtain a film-covered sheet.

(5) The film-covered sheet is cut into a predetermined size to obtain a cut sheet.

(6) The cut sheet is subjected to high pressure forming to obtain a semi-finished product 31 having an inner snap structure 321. The height of the semi-finished product 31 is between 4mm and 8 mm.

As shown in fig. 3, the cut sheet is high-pressure molded by a preset die 20. Referring to fig. 1 and 2, the premold 20 includes: the upper die comprises a lower die 201, a second upper die 202 and a second upper die 203, wherein the upper surface of the lower die 201 is provided with a forming groove 2011, the inner side wall of the forming groove 2011 is curved, the first upper die 202 is provided with a first boss 2021, the outward side surface of the first boss 2021 is curved and is recessed inwards, the second upper die 203 is provided with a second boss 2031, the outward side surface of the second boss 2031 is curved and is recessed inwards, the first boss 2021 and the second boss 2031 can enclose an annular matching boss 204, a matching groove 205 is formed in the area between the first upper die 202 and the second upper die 203 and below the matching boss 204, the matching groove 205 can be matched with the lower die 201, the matching boss 204 is matched with the upper surface of the lower die 201 when the first upper die 202 and the second upper die 203 enclose the periphery of the lower die 201, the side surface of the first boss 2021, the side surface of the second boss 2031 and the inner wall of the molding groove 2011 form an arc-shaped surface 206 for obtaining the inside buckle structure. The semi-finished product 31 is obtained through the pre-mold 20, as shown in fig. 4.

The technological parameters during high-pressure forming comprise: the heating temperature is 200-400 ℃, the heating time is 40-100 s, the forming blowing pressure is 30-60 Kgf, the pressure maintaining time is 1-60 s, and the mold temperature of the mold is preset to be 100-150 ℃.

(7) The semi-finished product 31 is subjected to CNC processing, which is to remove an excessive skirt portion, to obtain a 3D shaped sheet 32, as shown in fig. 5. The height of the CNC-treated 3D profiled sheet 32 is between 3mm and 7 mm.

Further, the method further comprises a step (8) of hardening and UV curing the 3D forming sheet 32 after post-processing to obtain the shell.

(1) compared with the traditional high-pressure process, the invention realizes the integrated molding structure of the middle frame and the machine body on the plastic sheet, greatly improves the design freedom of the product and improves the integration degree of the terminal product.

Example 1

The embodiment provides a shell integrally-formed preparation method, which comprises the following steps:

(1) a plastic sheet made of 0.7mm transparent PC material was taken. And (3) adopting a UV transfer printing process to transfer the UV grains on the plastic sheet to obtain a transfer printing sheet, wherein the thickness of the UV grains is 10 mu m.

(3) Performing silk-screen printing on the PVD film layer to obtain a silk-screen sheet; the thickness of the printing ink is 20 mu m during silk-screen printing.

(6) The cut sheet is subjected to high pressure forming to obtain a semi-finished product 31 having an inner snap structure 321. The height of the semi-finished product 31 is 4 mm.

The technological parameters during high-pressure forming comprise: the IR heating temperature is 200 ℃, the IR baking time is 40s, the forming blowing pressure is 30Kgf, the pressure maintaining time is 60s, and the mold temperature of the preset mold is 150 ℃.

(7) The semi-finished product 31 is subjected to CNC processing to obtain a 3D formed sheet 32, the CNC processing being to remove an excessive skirt portion of the semi-finished product 31. The height of the CNC-processed 3D profiled sheet 32 is 5 mm.

(8) The 3D molded sheet 32 is hardened and UV cured to obtain a housing. The size of the shell product meets the requirement, and the problems of obvious warping and deformation are solved.

Example 2

(1) taking a plastic sheet prepared from the PC + PMMA composite material with the thickness of 0.8 mm. And (3) adopting a UV transfer printing process to transfer the UV grains on the plastic sheet to obtain a transfer printing sheet, wherein the thickness of the UV grains is 8 mu m.

(2) Performing PVD coating on the UV lines to form a PVD coating to obtain a coated sheet, wherein the PVD coating is TiO₂Layer thickness 80 nm.

(3) Performing silk-screen printing on the PVD film layer to obtain a silk-screen sheet; and the thickness of the printing ink is 25 mu m during silk-screen printing.

(6) The cut sheet is subjected to high pressure forming to obtain a semi-finished product 31 having an inner snap structure 321. The height of the 3D semi-finished product 31 is 6 mm.

The technological parameters during high-pressure forming comprise: the IR heating temperature is 300 ℃, the IR baking time is 60s, the forming blowing pressure is 40Kgf, the pressure maintaining time is 40s, and the preset mold temperature of the mold is 140 ℃.

(7) The semi-finished product 31 is subjected to CNC processing to obtain a 3D formed sheet 32, the CNC processing being to remove an excessive skirt portion of the semi-finished product 31. The height of the CNC-processed 3D profiled sheet 32 was 6 mm.

Example 3

(1) taking a plastic sheet prepared from 1.5mm PMMA material. And (3) adopting a UV transfer printing process to transfer the UV grains on the plastic sheet to obtain a transfer printing sheet, wherein the thickness of the UV grains is 30 mu m.

(3) Performing silk-screen printing on the PVD film layer to obtain a silk-screen sheet; the thickness of the printing ink is 50 mu m during silk-screen printing.

(6) The cut sheet is subjected to high pressure forming to obtain a semi-finished product 31 having an inner snap structure 321. The height of the semi-finished product 31 is 8 mm.

The technological parameters during high-pressure forming comprise: the IR heating temperature is 400 ℃, the IR baking time is 100s, the forming blowing pressure is 60Kgf, the pressure maintaining time is 10s, and the mold temperature of the preset mold is 120 ℃.

(7) The semi-finished product 31 is subjected to CNC processing to obtain a 3D formed sheet 32, the CNC processing being to remove an excessive skirt portion of the semi-finished product 31. The height of the CNC-processed 3D profiled sheet 32 is 7 mm.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. The shell integrally-formed preparation method is characterized by comprising the following steps of:

(1) transferring UV lines on the plastic sheet to obtain a transfer sheet;

2. The method for integrally manufacturing a housing according to claim 1, wherein the thickness of the plastic sheet in step (1) is between 0.5mm and 2.0 mm.

3. The method for preparing the shell in an integrally formed manner according to claim 1, wherein the plastic sheet in the step (1) is a plastic sheet prepared from PC, PMMA or a composite material of PC and PMMA.

4. The integrally formed manufacturing method of casing as claimed in any one of claims 1 to 3, wherein the thickness of the UV veins in step (1) is between 3 μm and 30 μm.

5. A method for manufacturing a casing in an integrated manner as claimed in any one of claims 1 to 3, wherein the thickness of the ink during silk-screen printing in step (3) is between 5 μm and 50 μm.

6. The integrally formed manufacturing method of casing as claimed in any one of claims 1 to 3, wherein the height of the semi-finished product in step (6) is between 4mm and 8 mm.

7. The case body integrally formed manufacturing method of any one of claims 1 to 3, wherein the CNC processing in step (7) is to remove an unnecessary skirt portion of the semi-finished product, and the height of the CNC processed 3D formed sheet is between 3mm and 7 mm.

8. The integrally formed manufacturing method of a housing as claimed in any one of claims 1 to 3, wherein the cut sheet is high-pressure formed by a preset die in the step (6), the preset die comprising: a lower die, a second upper die and a second upper die, wherein the upper surface of the lower die is provided with a forming groove, the inner side wall of the forming groove is curved, the first upper pressing die is provided with a first boss, the outward side surface of the first boss is curved and is sunken, the second upper pressing die is provided with a second boss, the outward side surface of the second boss is in a shape of an inwards sunken curved surface, the first boss and the second boss can enclose an annular matching boss, a matching groove is formed in the area between the first upper pressing die and the second upper pressing die and below the matching boss, the matching groove can be matched with the lower pressing die, the matching lug boss is in contact matching with the upper surface of the lower pressing die when the first upper pressing die and the second upper pressing die are arranged around the lower pressing die, the side surface of the first boss, the side surface of the second boss and the inner wall of the forming groove form an arc-shaped surface for obtaining the inner buckle structure.

9. The method for preparing the shell in an integrally formed mode according to claim 8, wherein the process parameters during the high-pressure forming in the step (6) comprise: the heating temperature is 200-400 ℃, the heating time is 40-100 s, the forming blowing pressure is 30-60 Kgf, the pressure maintaining time is 1-60 s, and the mold temperature of the preset mold is 100-150 ℃.

10. The method for manufacturing the shell body integrally formed according to any one of claims 1 to 3, further comprising a step (8) of hardening and UV curing the 3D formed sheet to obtain the shell body.

11. A shell obtained by the shell integrally-forming preparation method according to any one of claims 1 to 10.