CN111516213A

CN111516213A - Manufacturing method of high-precision texture injection mold

Info

Publication number: CN111516213A
Application number: CN202010293235.XA
Authority: CN
Inventors: 李泽辉
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-04-15
Filing date: 2020-04-15
Publication date: 2020-08-11

Abstract

The invention discloses a manufacturing method of a high-precision texture injection mold, which comprises the following steps: s1, manufacturing the high-precision texture to be manufactured on the initial mould; s2, copying the texture onto a stretchable second mold to obtain a second texture mold; s3, copying the second texture mold according to the shape of the product to obtain a copying mold; s4, manufacturing the profiling mold by adopting an electroforming method to obtain a production mold with the softening temperature of more than 500 ℃; and S5, arranging the production mold in an injection mold frame to obtain the high-precision texture injection mold. According to the invention, the injection mold which is matched with the product shape and has high-precision texture is obtained through the gradual manufacturing of the initial texture mold, the second texture mold, the profiling mold and the production mold, and the problems that the existing texture in the processing of the existing 3D injection mold is different in thickness, the texture cannot be arranged in a consistent manner, the appearance is not clean and tidy, the visual effect, the fineness and the dazzling effect are poor, and the high-precision texture is suitable for flat plates are effectively solved.

Description

Manufacturing method of high-precision texture injection mold

Technical Field

The invention relates to a manufacturing method of an injection mold, in particular to a manufacturing method of a high-precision texture injection mold.

Background

With the continuous development of the field of electronic devices, electronic products have more and more important roles in our lives, and meanwhile, the requirements of people on the exquisite degree of appearance decoration of the electronic products are continuously improved.

At present, the back shells of various portable electronic products including mobile phones, especially the back shells of electronic products with textures and dazzling light effects arranged on the outer surfaces are mainly manufactured by IML and IMT technologies. However, the adoption of the IML and IMT processes requires that the diaphragm is separately manufactured and placed in an injection mold, the process is complex, the yield is low, and the rear shell with texture cannot be manufactured by adopting a direct mold opening mode; the rear shell of the existing electronic product is formed by integrally forming a bottom plate and a frame, if a mold is adopted for processing, the shape of the mold needs to be consistent with that of the product, and the mold needs to be provided with an inner concave surface. When the mold is used for processing the electronic product rear shell with the texture in the inner concave surface, the texture is generally pulled out on the surface of the mold by adopting metal processing equipment. 3D injection mold can appear shaking because among the machining process, and the unable uniformity of guaranteeing (error >20 um) of distance between the shape of processing out the texture, the texture can appear the texture thickness and differ, leads to the naked eye to discern, and the unable uniformity of texture is arranged, the outward appearance is clean and tidy, visual effect, fineness, dazzle light effect relatively poor. If the photoetching machine is used for processing the textures, the precision is high, the width of the textures can reach 1-40um, various dazzling light or light column effects can be seen through naked eye identification, no textures can be seen, but the photoetching machine can only process the textures on a flat plate, and cannot process the textures on the inner concave surface.

Disclosure of Invention

In view of the above, the invention aims to provide a method for manufacturing a high-precision texture injection mold, which is characterized in that high-precision textures are manufactured on an initial mold, then copied on a stretchable second mold and subjected to profiling, and a production mold is manufactured to obtain the injection mold which is matched with the shape and radian of a product and has the high-precision textures, and the problems that the shape and the distance between the processed textures cannot guarantee consistency (the error is more than 20 micrometers) due to the fact that the existing 3D injection mold shakes in the machining process, the textures cannot be uniformly arranged, the appearances cannot be clean and tidy, the visual effect, the fineness and the dazzling effect are poor, and the high-precision textures are suitable for flat plates are effectively solved.

The invention adopts the technical scheme that the manufacturing method of the high-precision texture injection mold comprises the following steps:

s1, manufacturing the high-precision texture to be manufactured on an initial mold to obtain an initial texture mold;

s2, copying the texture on the initial texture mold obtained in S1 to a stretchable second mold to obtain a second texture mold;

s3, copying the second texture mould obtained in the step S2 according to the shape radian of the product to obtain a copying mould;

s4, manufacturing the copying mold obtained in the step S3 by an electroforming method to obtain a production mold;

wherein the softening temperature of the production mold is above 500 ℃;

and S5, arranging the production mold obtained in the step S4 in an injection mold frame to obtain the high-precision texture injection mold.

Preferably, the S4 further includes:

matching the production mold with a metal support piece, and manufacturing an outer layer at the outer bottom of the metal support piece by adopting an electroforming method, wherein the outer layer and the production mold are made of the same material and are coated on the metal support piece together for improving the support strength of the production mold;

wherein, the bottom of the metal support is flat, and the top of the metal support is matched with the production mold.

Preferably, the metal support is manufactured by a numerical control machining method according to the production mold obtained in S4.

Preferably, the production mold in S4 is a nickel sheet;

the specific process of the electroforming method is as follows: taking the profiling mold after the electric conduction treatment as a cathode of electroforming, taking metal nickel as an anode of electroforming, depositing a nickel sheet with the thickness of 200-500 mu m on the texture surface of the profiling mold by an electroforming method, and then removing the profiling mold to obtain the nickel sheet, namely the production mold.

Preferably, the specific process of profiling in S3 is as follows: covering the second texture mould on a forming mould matched with the shape radian of the product, baking for 20-25 s at 150-200 ℃, and copying the second texture mould by using high-pressure gas of high-pressure forming equipment after the second texture mould is softened.

Preferably, the width of the high-precision texture in S1 is 1-50 μm.

Preferably, in S1, the initial mold is a silicon crystal plate coated with photoresist, and the texture is formed on the initial mold by a photolithography exposure development method.

Preferably, the second mold in S2 is any one of polyester, polyethylene terephthalate, polymethyl methacrylate, and polyvinyl chloride.

Preferably, the specific process of copying the texture to the stretchable second mold in S2 is as follows: covering the second mold on the initial texture mold with the surface coated with the ultraviolet curing glue, carrying out imprinting, exposure curing and separation of the second mold to obtain the second texture mold.

Preferably, in the step S2, a metal halide lamp or an LED lamp is used for exposure, the spectrum of the LED lamp is 350 to 450nm, and the exposure time is 3 to 5 seconds.

The invention has the beneficial effects that: according to the invention, the high-precision texture is manufactured on the initial mould, the texture on the initial mould is copied on the stretchable second mould and is subjected to profiling, and then the production mould is manufactured, so that the injection mould which is matched with the shape and radian of a product and has the high-precision texture is obtained, and the problems that the shape of the processed texture and the distance between the textures cannot guarantee the consistency (the error is more than 20 mu m) due to the shake in the machining process of the existing 3D injection mould adopting metal processing, the texture can not be identified by naked eyes, the texture cannot be arranged in a consistent manner, the appearance is not clean and tidy, the visual effect, the fineness and the dazzling effect are poor, and the high-precision texture processed by a photoetching machine is only suitable for a flat plate are effectively solved.

Drawings

Fig. 1 is a flowchart of a method for manufacturing a high-precision texture injection mold according to an embodiment of the present invention;

FIG. 2 is a flowchart illustrating a method for manufacturing a high-precision texture injection mold according to an embodiment of the present invention;

fig. 3 is a structural diagram of an initial texture mold in the manufacturing method of the high-precision texture injection mold according to the embodiment of the present invention;

fig. 4 is a structural diagram of an initial texture mold and a second texture mold in the manufacturing method of the high-precision texture injection mold according to the embodiment of the invention;

fig. 5 is a structural diagram of the matching of a copying mold and a forming mold in the manufacturing method of the high-precision texture injection mold according to the embodiment of the invention;

FIG. 6 is a structural diagram of the matching of a copying mold and a production mold in the manufacturing method of the high-precision texture injection mold according to the embodiment of the invention;

FIG. 7 is a schematic structural diagram of an electroformed nickel mold core in a method of manufacturing a high-precision texture injection mold according to an embodiment of the present invention;

fig. 8 is a structural diagram of the assembly of an injection mold frame and an electroformed nickel mold core in the method for manufacturing a high-precision texture injection mold according to the embodiment of the present invention.

In the figure: 1. an initial texture mold; 2. a second texture mold; 3. profiling a mold; 4. producing a mould; 5. injection molding a mold frame; 6. a metal support; 7. an outer layer; 8. and (5) forming a die.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The invention provides a manufacturing method of a high-precision texture injection mold, which comprises the following steps:

s1, manufacturing the high-precision texture to be manufactured on the initial mold to obtain an initial texture mold 1;

therefore, a photoetching machine can be adopted to process high-precision textures on the initial mould of the flat plate structure;

s2, copying the texture on the initial texture mold 1 obtained in S1 to a stretchable second texture mold 2;

when a product with radian is manufactured, an initial die which cannot be stretched is not suitable any more; by copying the texture, the texture on the initial texture mould 1 which cannot be stretched is transferred to a second stretchable mould, and the product with the shape radian can be manufactured;

s3, copying the second texture mould 2 obtained in the step S2 according to the shape radian of the product to obtain a copying mould 3;

the shape radian of the profiling mold 3 is the same as that of a product to be produced;

in a specific embodiment, the texture of the profiling mold 3 can be provided on the outer surface or inside of the profiling mold 3 according to the needs of the product.

S4, manufacturing the copying mold 3 obtained in the step S3 by an electroforming method to obtain a production mold 4;

wherein the softening temperature of the production mold 4 is above 500 ℃;

the stretchable second texture mold 2 is usually a stretchable plate, the temperature resistance of the mold can not reach the injection temperature (about 300 ℃) of an injection mold, and the mold can not be directly used as the injection mold for injection molding, so the profiling mold 3 is manufactured into a production mold 4 by an electroforming method, the softening temperature of the production mold 4 can reach more than 500 ℃, and the production mold can be directly used as the injection mold.

And S5, arranging the production mold 4 obtained in the step S4 in an injection mold frame 5 to obtain the high-precision texture injection mold.

Example 1

The embodiment provides a manufacturing method of a high-precision texture injection mold, as shown in fig. 1, including the following steps:

therefore, a photoetching machine can be adopted to process high-precision textures on the initial mould of the flat plate structure; in general metal processing, the shape and distance of the processed texture cannot be guaranteed to be consistent (the error is more than 20 μm) due to the fact that the shape and distance of the processed texture are shaken in the process of a mechanical technician, so that the texture can be recognized by naked eyes, and the texture is different in thickness, so that the dazzling effect is poor. The line width of the texture processed by the photoetching machine reaches 1-50 mu m.

As shown in fig. 3, in order to obtain a high-precision texture, the initial mold is a silicon wafer coated with photoresist, and the texture is made on the initial mold by using an exposure and development method;

the specific process is as follows: coating a layer of photoresist with the thickness of 100 mu m on a silicon crystal plate, exposing by using a photoetching machine, developing, and finally washing off the photoresist of a photosensitive part to form textures, thereby obtaining an initial texture mould 1;

wherein the relevant parameters are:

a photoetching machine: the light source wavelength is 350-450 nm;

an exposure machine: visible light: g, line: 436 nm; ultraviolet light (UV): i line: 365 nm.

The line width of the texture is 5 to 50 μm, and the line height is 5 to 15 μm.

that is, the silicon crystal plate in S1 cannot be stretched into an arc shape, and therefore the texture on the silicon crystal plate is transferred to a stretchable material.

In operation, the stretchable material is generally selected from any one of a stretchable sheet material, i.e., polyester, polyethylene terephthalate, polymethyl methacrylate, and polyvinyl chloride.

When the texture is copied, the texture presentation materials used are: the ultraviolet light curing glue is glue which can be cured only by ultraviolet light irradiation, and can be acrylate specifically.

As shown in fig. 4, the specific process of copying the texture to the stretchable second mold in S2 is as follows: covering the second mold on the initial texture mold 1 coated with the ultraviolet curing glue on the surface, performing imprinting, exposure curing, and separating the second mold to obtain a second texture mold 2; in the specific operation, a metal halogen lamp or an LED lamp is used for exposure, the spectrum of the LED lamp is 350-450 nm, and the exposure time is 3-5 s.

The method comprises the steps of pouring ultraviolet curing glue on an initial texture mold 1, placing a second mold on the ultraviolet curing glue, impressing by using a roller press to fix the ultraviolet curing glue with texture on the second mold, then exposing by using a metal halogen lamp or an LED lamp (the main spectrum is 350-450 nm), fixing the ultraviolet curing glue with texture on the second mold after exposing for 3-5 s for curing, and then separating the second mold fixed with the curing glue from the initial mold to obtain a second texture mold 2.

the shape radian of the profiling mold 3 is the same as that of a product to be produced; in this way, the second texture mold 2 can be shaped into a product desired by a customer.

As shown in fig. 5, the specific process of profiling in S3 is as follows: covering the second texture mould 2 on a forming mould 8 matched with the shape radian of the product, baking for 20-25 s at 150-200 ℃, and copying the second texture mould 2 by adopting high-pressure gas of high-pressure forming equipment after the second texture mould 2 is softened.

In a specific embodiment, the forming die 8 may be a high pressure drawing die.

Firstly, manufacturing a high-pressure stretching die according to the shape of a product, when the high-pressure stretching die is manufactured, determining whether the high-pressure stretching die is concave or convex according to the texture of an injection molding product to be on the surface or inside, manufacturing the high-pressure stretching die into the concave if the texture is required to be on the inside of the product, and manufacturing the high-pressure stretching die into the convex if the texture is required to be on the outside of the product;

then covering the second texture mould 2 on a high-pressure stretching mould, baking for 20-25 s at 150-200 ℃ to soften the second texture mould 2, and after the second texture mould 2 is softened, adopting high-pressure gas (30-50 kgf/cm) of high-pressure forming equipment²) Profiling the second texture mould 2.

wherein the softening temperature of the production mold 4 is above 500 ℃;

In a specific embodiment, the production mold 4 is a nickel sheet; the softening temperature of the nickel sheet reaches more than 500 ℃, and the nickel sheet can be directly used as an injection mold

The specific process of the electroforming method is as follows: taking the profiling mold 3 after the conductive treatment as a cathode of electroforming, taking metal nickel as an anode of electroforming, depositing a nickel sheet with the thickness of 200-500 mu m on the texture surface of the profiling mold 3 by an electroforming method, and then removing the profiling mold 3 to obtain the nickel sheet, namely the production mold 4.

As shown in fig. 6, the profiling mold 3 is subjected to a conductive treatment by using vacuum coating or metal powder spraying, that is, nickel is used as an electroplated layer, and a layer of metal powder is coated on the surface of the profiling mold 3, or a layer of metal powder is directly sprayed on the surface of the profiling mold 3, so that the profiling mold 3 after the conductive treatment overcomes the defect that the profiling mold 3 is not conductive, and can be used for an electroforming process;

then, by using an electroforming process, the profiling mold 3 after the conductive treatment is used as an electroforming cathode, metal nickel is used as an electroforming anode, a nickel sheet with the thickness of 200-500 μm is generated on the texture surface of the profiling mold 3, and then the profiling mold 3 is removed to obtain the nickel sheet, namely the production mold 4.

The specific parameters of the electroforming process refer to the existing method; in a specific embodiment, the electroforming solution in the electroforming process can be a solution containing 20-50g/L of boric acid, 5-20g/L of nickel chloride, 200-500g/L of nickel sulfamate and pH of 3.0-4.5, the electroforming temperature can be 40-70 ℃, and the current density can be 1-15A/dm²。

At this time, the production mold 4 can be matched with the injection mold frame 5 for producing injection molding products.

However, since the nickel plate is easily broken at a thickness of less than 200 μm due to low electroforming efficiency, a metal supporter 6 is added to the nickel plate, i.e., the production mold 4, in order to enhance the rigidity of the nickel plate and to reduce the electroforming time.

In a specific embodiment, the metal supporter 6 may be an iron plate.

As shown in fig. 7, the production mold 4 is matched with a metal support 6, an outer layer 7 is manufactured at the outer bottom of the metal support 6 by an electroforming method, the material of the outer layer 7 is the same as that of the production mold 4, and the outer layer 7 and the production mold 4 jointly coat the metal support 6 to improve the supporting strength of the production mold 4;

wherein the bottom of the metal support 6 is flat, and the top of the metal support is matched with the production mold 4; the metal support 6 is manufactured by a numerical control machining method according to the production mold 4.

Namely, a sheet of iron plate with the thickness of 1cm is manufactured by a data processing method (CNC) according to the profiling shape on the production mold 4, namely the nickel sheet, so as to obtain a metal support member 6, namely the iron plate, wherein the top of the iron plate is matched with the nickel sheet, and the bottom of the iron plate is a flat surface; then putting the iron plate under the nickel sheet with good profile modeling, and depositing a nickel layer outer layer 7 with the thickness of 200 mu m on the outer lower part and the bottom of the iron plate by using an electroforming process, so that the nickel layer outer layer 7 and the nickel sheet wrap the iron plate together, namely the nickel sheet with good profile modeling, the iron plate and the nickel layer outer layer 7 are completely fused into a whole.

Thus, the electroforming nickel mold core with high-precision textures fused into a whole is obtained, and the electroforming nickel mold core not only improves the supporting strength of the nickel sheet, but also improves the electroforming efficiency through the addition of the metal support piece 6.

Furthermore, different textures may also share the same injection mold frame 5.

As shown in fig. 1 or fig. 2, the production mold 4 may be a textured profiling nickel sheet or an electroformed nickel mold core with improved support strength.

As shown in fig. 8, the production mold 4 is inserted into the injection mold frame 5, and injection molding is performed, and the product obtained by injection molding directly shows the precise texture.

The working principle is as follows: when the injection mold of the embodiment is manufactured, firstly, high-precision textures to be manufactured are manufactured on an initial mold, namely, the high-precision textures are processed on the initial mold of a flat plate structure by a photoetching machine, so that an initial texture mold is obtained; then the texture on the initial texture mould is copied to a stretchable second mould, so that the second mould has high-precision texture and can be used for manufacturing products with shape radians to obtain a second texture mould; then, copying the second texture mould according to the shape radian of the product to obtain a copying mould; then, manufacturing the profiling mold by adopting an electroforming method to obtain a production mold which has the softening temperature of more than 500 ℃ and can be directly used for an injection mold; and finally, arranging the production mold in an injection mold frame to obtain the high-precision texture injection mold.

This embodiment is through making high-accuracy texture to the primary mold on, the texture on the primary mold is copied to can tensile second mould and carry out the profile modeling again, then make production mould, obtain and just have the injection mold of high-accuracy texture with product shape radian looks adaptation, effectively solved current adoption 3D injection mold because the shake can appear in the machining process, process out the shape of texture, the unable uniformity of guaranteeing (error >20 um) of distance between the texture, the texture thickness can appear differently, lead to naked eye to discern, the unable uniformity of texture is arranged, the outward appearance is unclean and tidy, visual effect, fine and smooth degree, dazzle the relatively poor problem of light effect. And the problem that the high-precision texture processed by the photoetching machine is only suitable for a flat plate; meanwhile, the metal support is added into the production die, namely the nickel sheet, so that the support strength of the nickel sheet is improved, and the electroforming efficiency is improved.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. The manufacturing method of the high-precision texture injection mold is characterized by comprising the following steps of:

wherein the softening temperature of the production mold is above 500 ℃;

2. The method as claimed in claim 1, wherein the step S4 further comprises:

3. The method of claim 2, wherein the metal support is fabricated by a numerical control machining method according to the production mold.

4. The method for manufacturing a high precision texture injection mold as claimed in any one of claims 1 to 3, wherein the mold produced in S4 is a nickel sheet;

5. The method for manufacturing a high-precision texture injection mold as claimed in claim 1, wherein the specific process of profiling in the step S3 is as follows: covering the second texture mould on a forming mould matched with the shape radian of the product, baking for 20-25 s at 150-200 ℃, and copying the second texture mould by using high-pressure gas of high-pressure forming equipment after the second texture mould is softened.

6. The method for manufacturing an injection mold with high-precision textures as claimed in claim 1, wherein the width of the high-precision textures in S1 is 1-50 μm.

7. The method as claimed in claim 6, wherein the initial mold in S1 is a silicon wafer coated with photoresist, and the texture is formed on the initial mold by exposure and development of a photolithography machine.

8. The method as claimed in claim 1, wherein the second mold in S2 is any one of polyester, polyethylene terephthalate, polymethyl methacrylate, and polyvinyl chloride.

9. The method for manufacturing a high precision texture injection mold according to claim 1 or 8, wherein the specific process of copying the texture to the stretchable second mold in the step S2 is as follows: covering the second mold on the initial texture mold with the surface coated with the ultraviolet curing glue, carrying out imprinting, exposure curing and separation of the second mold to obtain the second texture mold.

10. The method for manufacturing a high-precision texture injection mold according to claim 9, wherein a metal halogen lamp or an LED lamp is used for exposure in S2, the spectrum of the LED lamp is 350-450 nm, and the exposure time is 3-5S.