TWI884709B - Method for manufacturing mold for molding - Google Patents

Abstract

A method for manufacturing a mold for molding includes: providing a substrate having a substrate surface; forming a sacrificial layer on the substrate surface; performing laser processing on the substrate with the sacrificial layer formed thereon, to form a plurality of deep recessed holes that penetrate the sacrificial layer and are recessed into the substrate surface, wherein a recast portion remaining from laser processing is accumulated around the opening edge of each deep recessed hole, and the recast portion is located on the side of the sacrificial layer away from the substrate; and then the sacrificial layer and the recast portion are removed.

Description

Method for manufacturing molding die

The present invention relates to a method for manufacturing a mold, and in particular to a method for manufacturing a molding mold by laser processing.

It is a common method to use laser processing to make dots on the molding mold of light guide components. The molding mold is generally made of steel. The laser beam is focused on the surface of the steel, and the steel surface is heated to melt and vaporize to form tiny concave holes. Some molten steel material accumulates around the concave holes to form a crater-shaped recast structure. This crater-shaped recast structure will be transferred to the light guide component after molding, resulting in undesirable optical properties of the light guide component; or when using this molding mold for injection molding, the recast structure may increase the plastic flow resistance or make demolding difficult; in addition, due to the formation of the recast structure, the laser spot diameter is enlarged, resulting in the risk of visible dots on the light guide component.

Currently, the common method of removing heavy casting structures is to use a tool to plane the steel surface to remove the protrusions on the steel surface including the periphery of the concave hole; or to remove the protrusions around the concave hole through a grinding process. However, in the method of cutting the steel surface through a tool, the tool needs to move in a direction parallel to the steel surface, and the tool base plane adjustment is difficult; and in the method of removing the protrusions around the concave hole through a grinding process, the area with a higher density of concave holes requires a longer grinding time, resulting in different sizes of concave holes on the steel.

The "Prior Art" section is only used to help understand the content of the present invention. Therefore, the content disclosed in the "Prior Art" section may contain some knowledge that does not constitute the common knowledge in the relevant technical field. The content disclosed in the "Prior Art" section does not mean that the content or the problems to be solved by one or more embodiments of the present invention have been known or recognized by the common knowledge in the relevant technical field before the application of the present invention.

The present invention provides a method for manufacturing a molding die, which can effectively remove the protruding recast portion around the concave hole and obtain a molding die with a consistent concave hole size.

Other purposes and advantages of the present invention can be further understood from the technical features disclosed in the present invention.

To achieve one or part or all of the above purposes or other purposes, a manufacturing method of a molding mold in an embodiment of the present invention includes: providing a substrate having a substrate surface; forming a sacrificial layer on the substrate surface; performing laser processing on the substrate with the sacrificial layer to form a plurality of deep recessed holes penetrating the sacrificial layer and recessed into the substrate surface, wherein a recast portion remaining from the laser processing is accumulated around the opening of each deep recessed hole, and the recast portion is located on a side of the sacrificial layer away from the substrate; and removing the sacrificial layer and the recast portion.

In one embodiment of the present invention, after removing the sacrificial layer and the recast portion, a plurality of shallow recesses are formed on the substrate surface at positions corresponding to the deep recesses, and the shallow recesses have the same size.

In one embodiment of the present invention, the maximum inner diameter of the deep concave hole is the first inner diameter, and the maximum inner diameter of the shallow concave hole is the second inner diameter, and the second inner diameter is smaller than the first inner diameter.

In one embodiment of the present invention, after removing the sacrificial layer and the recast portion, a polishing process is further included for the substrate having the shallow concave hole formed therein.

In one embodiment of the present invention, the thickness of the substrate is greater than or equal to the thickness of the sacrificial layer, and the thickness of the sacrificial layer is greater than 0.1 micrometers and less than or equal to 300 micrometers.

In one embodiment of the present invention, before forming the above-mentioned sacrificial layer, the surface of the substrate is passivated to form a passivation layer, and the passivation layer is located between the substrate and the sacrificial layer.

In one embodiment of the present invention, the passivation layer and the sacrificial layer have a first total thickness, the thickness of the substrate is greater than or equal to the first total thickness, and the first total thickness is greater than 0.1 micrometers and less than or equal to 300 micrometers.

In one embodiment of the present invention, the above-mentioned passivation layer and the substrate have a second total thickness, the second total thickness is greater than or equal to the thickness of the sacrificial layer, and the thickness of the sacrificial layer is greater than 0.1 microns and less than or equal to 300 microns.

In one embodiment of the present invention, the sacrificial layer and the recast portion are removed by a pickling step.

In one embodiment of the present invention, the material of the above-mentioned substrate is steel.

In one embodiment of the present invention, the sacrificial layer is an electroplated nickel layer or an electroplated copper layer.

In one embodiment of the present invention, the direction in which the laser beam of the above-mentioned laser processing enters the substrate is perpendicular to the substrate surface, or forms a specific angle with the substrate surface.

The present invention forms a sacrificial layer on the surface of a substrate (or forms a passivation layer on the surface of a substrate first and then forms a sacrificial layer), and removes the sacrificial layer after laser processing. The crater-shaped recast portion accumulated around the opening of the deep concave hole can be removed together with the sacrificial layer, and a shallow concave hole without a recast portion can be formed on the substrate, and the size of the shallow concave hole is consistent. The method of removing the recast portion can solve the difficulty of controlling the cutting reference surface of the tool in the conventional method of removing the recast portion by cutting, and can also improve the defect of inconsistent size of the shallow concave hole caused by the conventional method of removing the recast portion by grinding.

In order to make the above and other purposes, features and advantages of the present invention more clearly understood, the following is a detailed description of the preferred embodiment with the accompanying drawings.

10:Substrate

101:Substrate surface

12: Sacrifice layer

14: Deep concave hole

16: Recasting Department

18: Shallow concave hole

r1: first inner diameter

r2: Second inner diameter

_DB , _DS : thickness

D1: Total first thickness

D2: Second thickness sum

20: Laser beam

22, 22’: Passivation layer

24: Rough edges

30: Molding mold

Figures 1A to 1D are cross-sectional schematic diagrams of a method for manufacturing a molding die according to an embodiment of the present invention.

Figure 2 is a schematic top view of the sacrificial layer and deep recessed hole of an embodiment of the present invention.

FIG3 is a schematic top view of a substrate and a shallow concave hole according to an embodiment of the present invention.

Figures 4A to 4E are cross-sectional schematic diagrams of a method for manufacturing a molding die according to another embodiment of the present invention.

The other technical contents, features and effects of the present invention mentioned above will be clearly presented in the detailed description of the preferred embodiment with reference to the following drawings. The directional terms mentioned in the following embodiments, such as up, down, left, right, front or back, etc., are only referenced to the directions of the attached drawings. Therefore, the directional terms used are used to illustrate and are not used to limit the present invention.

1A to 1D are cross-sectional schematic diagrams of a method for manufacturing a molding die according to an embodiment of the present invention. As shown in FIG1A , a substrate 10 is provided, and the substrate 10 has a substrate surface 101 . As shown in FIG1B , a sacrificial layer 12 is formed on the substrate surface 101 . Next, as shown in FIG1C , the substrate 10 formed with the sacrificial layer 12 is laser processed to form a plurality of deep recessed holes 14 penetrating the sacrificial layer 12 and recessed into the substrate surface 101. Please also refer to FIG2 , which is a schematic top view of the sacrificial layer 12 and the deep recessed holes 14 of an embodiment of the present invention, wherein a recast portion 16 remaining from the laser processing is accumulated around the opening of each deep recessed hole 14, and the recast portion 16 is located on a side of the sacrificial layer 12 away from the substrate 10. After that, the sacrificial layer 12 and the recast portion 16 are removed, as shown in FIG1D , and a plurality of shallow recesses 18 are formed on the substrate surface 101 at positions corresponding to the deep recesses 14 (marked in FIG1C ). Please also refer to FIG3 , which is a schematic top view of a substrate 10 and shallow recesses 18 according to an embodiment of the present invention, wherein the shallow recesses 18 are distributed on the substrate surface 101 and the shallow recesses 18 may have the same size. In one embodiment, the maximum inner diameter of the deep recess 14 is, for example, the first inner diameter r1 (marked in FIG1C ), and the maximum inner diameter of the shallow recess 18 is, for example, the second inner diameter r2 (marked in FIG1D ), and the second inner diameter r2 is smaller than the first inner diameter r1.

300μm。犧牲層12例如為電鍍鎳層或電鍍銅層，惟不限於金屬，犧牲層12可以為任何在雷射加工後能自基板10移除的材質。 The material of the substrate 10 can be steel, such as SUS304, SUS430 or SUS420; the substrate 10 can be a thin plate, a thick plate or a module. As shown in FIG. 1A and FIG. 1B , the thickness _DB of the substrate 10 is greater than or equal to the thickness _DS of the sacrificial layer 12. In one embodiment, the thickness _DS of the sacrificial layer 12 is greater than 0.1 micrometers and less than or equal to 300 micrometers, that is, 0.1μm< _DS

The sacrificial layer 12 is, for example, an electroplated nickel layer or an electroplated copper layer, but is not limited to metals. The sacrificial layer 12 can be any material that can be removed from the substrate 10 after laser processing.

The laser processing is, for example, using a solid state Nd:YAG laser or a fiber laser to process the substrate 10 coated with the sacrificial layer 12 to form the deep recessed hole 14. The direction in which the laser beam 20 of the laser processing enters the substrate 10 can be perpendicular to the substrate surface 101 (as shown in FIG. 1C ), or form a specific angle with the substrate surface 101. During the laser processing of the workpiece (i.e., the substrate 10 formed with the sacrificial layer 12), the laser beam 20 is focused on the workpiece surface, and the workpiece surface is heated to melt and vaporize to form a tiny deep concave hole 14, and some molten workpiece material is accumulated around the deep concave hole 14 to form a heavy casting part 16 like a crater, wherein the working surface is, for example, the surface of the sacrificial layer 12, and the molten workpiece material includes, for example, the molten substrate 10 and the molten sacrificial layer 12. In one embodiment, the maximum inner diameter (i.e., the first inner diameter r1) of the deep concave hole 14 can be between 10 microns and 100 microns, and the depth of the deep concave hole 14 is greater than the thickness of the sacrificial layer 12, for example, the thickness of the sacrificial layer 12 is 4 microns, and the depth of the deep concave hole 14 formed by laser processing is 8 microns.

Continuing with the above description, in one embodiment of the present invention, after removing the sacrificial layer 12 and the recast portion 16, a polishing process is further included for the substrate 10 formed with the shallow recessed hole 18. Specifically, in one embodiment, the sacrificial layer 12 and the recast portion 16 can be removed by an acid pickling step, wherein the acid pickling step is, for example, to dissolve the sacrificial layer 12 using dilute nitric acid. Although the recast portion 16 is not easily dissolved by dilute nitric acid, most of the recast portion 16 can be removed along with the removal of the sacrificial layer 12, and the remaining recast portion 16 can be easily removed by a subsequent polishing process.

In the manufacturing method of the molding mold of the embodiment of the present invention, by forming a sacrificial layer 12 on the substrate surface 101 and removing the sacrificial layer 12 after laser processing, the crater-shaped recast portion 16 accumulated around the opening of the deep concave hole 14 can be removed together with the sacrificial layer 12, and a shallow concave hole 18 without the recast portion 16 is formed on the substrate 10. The substrate 10 with the shallow concave hole 18 can be directly used as a molding mold 30, or can be reproduced as an electroplating plate or a soft mold and then used as a molding mold, so that the surface of the light guide plate produced by injection molding has convex points or concave points transferred from the shallow concave hole, which serves as a microstructure for controlling the light emission of the light guide plate.

4A to 4E are cross-sectional schematic diagrams of a method for manufacturing a molding die according to another embodiment of the present invention. As shown in FIG4A , a substrate 10 is provided, the substrate 10 has a substrate surface 101, and the substrate surface 101 is passivated to form a passivation layer 22 on the substrate surface 101. Then, as shown in FIG4B , a sacrificial layer 12 is formed on a side of the passivation layer 22 away from the substrate 10, so that the passivation layer 22 is between the substrate 10 and the sacrificial layer 12. Next, as shown in FIG. 4C , the substrate 10 formed with the sacrificial layer 12 and the passivation layer 22 is laser processed to form a plurality of deep recessed holes 14 penetrating the sacrificial layer 12 and the passivation layer 22 and recessed into the substrate surface 101, wherein a recast portion 16 left over from the laser processing is accumulated around the opening of each deep recessed hole 14, and the recast portion 16 is located on the side of the sacrificial layer 12 away from the substrate 10. Afterwards, the sacrificial layer 12 and the recast portion 16 are removed, as shown in FIG. 4D , and a plurality of shallow recessed holes 18 are formed on the substrate 10 at positions corresponding to the deep recessed holes 14 (shown in FIG. 4C ).

Continuing with the above description, in one embodiment, the passivation layer 22 is, for example, an oxide layer, as shown in FIG. 4B and FIG. 4C . The provision of the passivation layer 22 can facilitate the removal of the sacrificial layer 12. Specifically, the bond between the passivation layer 22 and the substrate 10 is stronger, and the bond between the passivation layer 22 and the sacrificial layer 12 is weaker; when the sacrificial layer 12 is removed, the passivation layer 22 will still be attached to the substrate 10. In one embodiment, when laser processing is performed on a workpiece (i.e., a substrate 10 formed with a sacrificial layer 12 and a passivation layer 22), a portion of the molten workpiece material is not only accumulated around the deep recessed hole 14 to form a recast portion 16, but also solidifies in the area between the sacrificial layer 12 and the passivation layer 22. Therefore, after the sacrificial layer 12 is removed, the solidified molten workpiece material may form burrs 24 remaining on the passivation layer 22. In addition, the above-mentioned molten workpiece material includes, for example, the molten substrate 10, the molten passivation layer 22, and the molten sacrificial layer 12.

In the manufacturing method of the molding mold of an embodiment of the present invention, after removing the sacrificial layer 12 and the recast portion 16, a polishing process is further included for the substrate 10 formed with the shallow concave hole 18, as shown in FIG. 4E, to remove the remaining burrs 24 (indicated in FIG. 4D). In one embodiment, the polishing process is, for example, velvet polishing. After velvet polishing, in addition to removing the remaining burrs 24, a portion of the passivation layer 22 will be removed together, and the portion of the passivation layer 22' remaining on the surface of the substrate will not affect the surface roughness of the substrate 10, in other words, will not affect the surface roughness of the light guide plate emitted later.

In one embodiment of the present invention, as indicated on the left side of FIG. 4B , the passivation layer 22 and the sacrificial layer 12 have a first thickness sum D1, the thickness _DB of the substrate 10 is greater than or equal to the first thickness sum D1, and the first thickness sum D1 is greater than 0.1 micrometers and less than or equal to 300 micrometers. Alternatively, as indicated on the right side of FIG. 4B , the passivation layer 22 and the substrate 10 have a second thickness sum D2, the second thickness sum D2 is greater than or equal to the thickness _DS of the sacrificial layer 12, and the thickness _DS of the sacrificial layer 12 is greater than 0.1 micrometers and less than or equal to 300 micrometers.

In summary, in the manufacturing method of the molding die of the embodiment of the present invention, by forming a sacrificial layer on the surface of the substrate (or first forming a passivation layer on the surface of the substrate and then forming the sacrificial layer), and removing the sacrificial layer after laser processing, the crater-shaped recast portion accumulated around the opening of the deep concave hole can be removed together with the sacrificial layer, and a shallow concave hole without a recast portion can be formed on the substrate. The method of removing the recast portion can solve the difficulty of controlling the cutting reference surface of the tool in the known removal of the recast portion by cutting method, and can also improve the defect of inconsistent size of the shallow concave hole caused by the known removal of the recast portion by grinding method.

On the other hand, due to the removal of the recast part, a simple shallow concave hole is obtained, which can reduce the undesirable optical properties of the transferred light guide plate such as stray light caused by the recast part; and when the molding mold is used as an injection molding mold, the resistance of plastic flow during injection can be reduced. In addition, with the removal of the sacrificial layer and the recast part, the maximum inner diameter (second inner diameter) of the shallow concave hole on the substrate is smaller than the maximum inner diameter (first inner diameter) of the deep concave hole, that is, the laser spot diameter will be reduced, which can reduce the diameter of the light guide plate dots and reduce the risk of dots being visible.

However, the above is only the preferred embodiment of the present invention, and it cannot be used to limit the scope of the implementation of the present invention. That is, all simple equivalent changes and modifications made according to the scope of the patent application and the content of the invention description are still within the scope of the present invention. In addition, any embodiment or patent application of the present invention does not need to achieve all the purposes, advantages or features disclosed by the present invention. In addition, the abstract and title are only used to assist in searching patent documents, and are not used to limit the scope of rights of the present invention. In addition, the terms "first" and "second" mentioned in this specification or patent application are only used to name the element or distinguish different embodiments or scopes, and are not used to limit the upper or lower limit of the number of elements.

10:Substrate

101:Substrate surface

12: Sacrifice layer

14: Deep concave hole

16: Recasting Department

r1: first inner diameter

20: Laser beam

Claims (11)

A method for manufacturing a molding die includes: providing a substrate having a substrate surface; forming a sacrificial layer on the substrate surface; performing a laser process on the substrate with the sacrificial layer formed thereon to form a plurality of deep recessed holes penetrating the sacrificial layer and recessed into the substrate surface, wherein a recast portion remaining from the laser process is accumulated around the opening of each of the deep recessed holes, and the recast portion is located on a side of the sacrificial layer away from the substrate; and removing the sacrificial layer and the recast portion, wherein before forming the sacrificial layer, the method further includes performing a passivation process on the substrate surface to form at least one passivation layer, and the at least one passivation layer is located between the substrate and the sacrificial layer. A method for manufacturing a molding die as described in claim 1, wherein after removing the sacrificial layer and the recast portion, a plurality of shallow recessed holes are formed on the substrate surface at positions corresponding to the deep recessed holes, and the shallow recessed holes have the same size. A method for manufacturing a molding die as described in claim 2, wherein the maximum inner diameter of each of the deep recesses is a first inner diameter, and the maximum inner diameter of each of the shallow recesses is a second inner diameter, and the second inner diameter is smaller than the first inner diameter. The manufacturing method of the molding die as described in claim 2 further includes a polishing process for the substrate having the shallow recessed holes formed therein after removing the sacrificial layer and the recast portion. A method for manufacturing a molding die as described in claim 1, wherein the thickness of the substrate is greater than or equal to the thickness of the sacrificial layer, and the thickness of the sacrificial layer is greater than 0.1 micrometers and less than or equal to 300 micrometers. The manufacturing method of the molding die as described in claim 1, wherein the at least one passivation layer and the sacrificial layer have a first thickness sum, the thickness of the substrate is greater than or equal to the first thickness sum, and the first thickness sum is greater than 0.1 micrometers and less than or equal to 300 micrometers. The manufacturing method of the molding die as described in claim 1, wherein the at least one passivation layer and the substrate have a second thickness sum, the second thickness sum is greater than or equal to the thickness of the sacrificial layer, and the thickness of the sacrificial layer is greater than 0.1 micrometers and less than or equal to 300 micrometers. A method for manufacturing a molding die as described in claim 1, wherein the sacrificial layer and the recast portion are removed by a pickling step. A method for manufacturing a molding die as described in claim 1, wherein the substrate is made of steel. The method for manufacturing a molding die as described in claim 1, wherein the sacrificial layer is an electroplated nickel layer or an electroplated copper layer. A method for manufacturing a molding die as described in claim 1, wherein the direction in which the laser beam of the laser processing enters the substrate is perpendicular to the surface of the substrate, or forms a specific angle with the surface of the substrate.

Images