阅读说明：本技术 一种热压印用柔性金属微模具的制造方法 (Manufacturing method of flexible metal micro-mold for hot stamping ) 是由 杨海峰 时明天 刘昊 郝敬宾 刘新华 于 2020-05-11 设计创作，主要内容包括：本发明公开了一种热压印用柔性金属微模具的制造方法,首先对金属箔进行退火处理,消除内应力并降低硬度；然后采用金属箔表面微结构激光连续加工装置对退火后的金属箔进行加工,在金属箔的一面加工得到金属微模具需要的微结构；带有微结构的金属箔再次进行退火处理,去除金属箔内因加工产生的残余应力；最后将热塑性塑料薄膜或热固性塑料薄膜与金属箔无结构侧结合在一起,从而得到热压印用柔性金属微模具。本发明通过激光烧蚀牺牲层产生的热力耦合作用进行金属箔表面的微结构成型,具的绿色、高效的特点。(The invention discloses a manufacturing method of a flexible metal micro-mould for hot stamping, which comprises the following steps of firstly, carrying out annealing treatment on a metal foil, eliminating internal stress and reducing hardness; then processing the annealed metal foil by adopting a metal foil surface microstructure laser continuous processing device, and processing one side of the metal foil to obtain a microstructure required by a metal micromold; annealing the metal foil with the microstructure again to remove residual stress generated in the metal foil due to processing; and finally, combining the thermoplastic plastic film or the thermosetting plastic film with the unstructured side of the metal foil together to obtain the flexible metal micromold for hot stamping. The invention carries out the microstructure forming on the surface of the metal foil through the thermal coupling effect generated by laser ablation of the sacrificial layer, and has the characteristics of greenness and high efficiency.)

1. A method for manufacturing a flexible metal micromold for hot stamping is characterized by comprising the following steps:

step 1: annealing the metal foil to eliminate internal stress and reduce hardness;

step 2: processing the annealed metal foil by adopting a metal foil surface microstructure laser continuous processing device, and processing one side of the metal foil to obtain a microstructure required by a metal micromold;

and step 3: annealing the metal foil with the microstructure again to remove residual stress generated in the metal foil due to processing;

and 4, step 4: and combining the thermoplastic plastic film or the thermosetting plastic film with the unstructured side of the metal foil to obtain the flexible metal micromold for hot stamping.

2. The method of claim 1, wherein the metal foil has a thickness of not more than 200 μm, the annealing temperature in step 1 is higher than the recrystallization temperature of the metal foil and lower than 0.7 times the melting point, and the annealing time is not less than 20 min.

3. The method for manufacturing the flexible metal micromold for hot stamping according to claim 1, wherein the metal foil surface microstructure laser continuous processing device comprises a laser module and a material transfer module; the material transmission module comprises a bottom lifting platform (8) and a top lifting frame (5), wherein a master mould (7) is fixed on the bottom lifting platform (8), and a transparent transmission layer (4) is fixed on the top lifting frame (5); a first tensioning roller (13), a first unreeling roller (11) wound with a sacrificial layer (12) and a second unreeling roller (16) wound with a metal foil (17) are arranged on one side of the bottom lifting platform (8), and a second tensioning roller (14), a first reeling roller (15) for recycling the sacrificial layer (12) and a second reeling roller (18) for recycling the metal foil (17) are arranged on the other side of the bottom lifting platform (8); the sacrificial layer (12) and the metal foil (17) pass through between the master mould (7) and the transparent transmission layer (4) after being laminated and tensioned by the first tensioning roller (13) and the second tensioning roller (14); the laser module is positioned above the top lifting frame (5).

4. The method of manufacturing a flexible metal micromold for hot stamping according to claim 1, wherein in step 3, the annealing temperature is lower than the recrystallization temperature of the metal foil and higher than 0.2 times the melting point, and the annealing time is not less than 20 min.

5. The method of claim 1, wherein the thermoplastic or thermosetting plastic film has a thickness of no more than 1 mm.

6. The method for manufacturing a flexible metal micromold for hot embossing according to claim 3, wherein the transparent transfer layer (4) is glass having a thickness not less than 1 mm.

7. The method for manufacturing a flexible metal micromold for hot embossing according to claim 3, wherein the sacrificial layer (12) is a metal thin film having a thickness of less than 0.2mm and a black paint coated on the upper surface.

Technical Field

The invention relates to the technical field of manufacturing of metal micro molds, in particular to a manufacturing method of a flexible metal micro mold for hot stamping.

Background

Hot stamping is a high throughput, low cost microstructure fabrication technique by which the microstructure of a micromold surface can be accurately transferred to a polymeric substrate under appropriate temperature and pressure conditions. Hot stamping is considered a reliable method for fabricating high-precision micro-nano structures in both academic and industrial fields. Hot stamping has outstanding performance in various fields, and has advantages that other processes do not have when some microstructures with simple structures and regular arrangement are manufactured. The advantage makes the hot stamping have an important position in the fields of optics, biology, bionics, medicine and MEMS manufacture and the like. And the microstructure is manufactured on the surface of the polymer by adopting a hot stamping mode, and the method has the advantages of high forming efficiency, simple processing, high cost performance and the like. In recent years, roll-to-roll hot stamping techniques have been greatly developed, and higher demands have been made on metal micromold for hot stamping. In the roll-to-roll hot stamping process, the metal micro-mold with the microstructure on the surface plays a decisive role in the quality of hot stamping. The metal micro-mould commonly used at present mainly comprises an ultra-precision machining method, a LIGA technology and the like. The ultra-precision machining method can be used for manufacturing a high-precision micro-nano structure on the surface of a roll subjected to roll-to-roll hot stamping, but the method has high precision requirements on a machine tool and a cutter, is high in machining cost and is not suitable for large-area high-precision machining. The LIGA technology is to realize the processing of the metal micro-mold through the processes of exposure, etching, electroforming, demolding and the like, but the manufacturing process route is long, relates to the electrochemical technology, has pollution, low efficiency and the like, has large investment on manufacturing equipment, and is not suitable for large-area manufacturing.

Currently, there is still no method for manufacturing a metal micromold with a large area, simplicity and high efficiency for roll-to-roll hot stamping technology, and therefore, a new process for manufacturing a flexible metal micromold for hot stamping needs to be provided.

Disclosure of Invention

The purpose of the invention is as follows: in order to solve the problem of green and efficient manufacturing of the existing metal micro-die for roll-to-roll hot stamping, the method for manufacturing the flexible metal micro-die for hot stamping by using the laser continuous processing technology is provided.

The technical scheme is as follows: a manufacturing method of a flexible metal micromold for hot stamping comprises the following steps:

step 1: annealing the metal foil to eliminate internal stress and reduce hardness;

step 2: processing the annealed metal foil by adopting a metal foil surface microstructure laser continuous processing device, and processing one side of the metal foil to obtain a microstructure required by a metal micromold;

and step 3: annealing the metal foil with the microstructure again to remove residual stress generated in the metal foil due to processing;

and 4, step 4: and combining the thermoplastic plastic film or the thermosetting plastic film with the unstructured side of the metal foil to obtain the flexible metal micromold for hot stamping.

Further, the thickness of the metal foil is not more than 200 μm, the annealing temperature in the step 1 is higher than the recrystallization temperature of the metal foil and lower than 0.7 times of the melting point, and the annealing time is not less than 20 min.

Further, the metal foil surface microstructure laser continuous processing device comprises a laser module and a material transmission module; the material transmission module comprises a bottom lifting platform and a top lifting platform, wherein a primary mould is fixed on the bottom lifting platform, and a transparent transmission layer is fixed on the top lifting platform; a first tensioning roller, a first unreeling roller wound with a sacrificial layer and a second unreeling roller wound with a metal foil are arranged on one side of the bottom lifting platform, and a second tensioning roller, a first reeling roller for recycling the sacrificial layer and a second reeling roller for recycling the metal foil are arranged on the other side of the bottom lifting platform; the sacrificial layer and the metal foil pass through the space between the original die and the transparent transmission layer after being stacked and tensioned by the first tensioning roller and the second tensioning roller; the laser module is located above the top lifting frame.

Further, in the step 3, the annealing temperature is lower than the recrystallization temperature of the metal foil and higher than 0.2 times of the melting point, and the annealing time is not less than 20 min.

Further, the thickness of the thermoplastic plastic film or the thermosetting plastic film is not more than 1 mm.

Further, the transparent transmission layer is made of glass with the thickness not less than 1 mm.

Furthermore, the sacrificial layer is a metal film with the thickness of less than 0.2mm and the upper surface covered with black paint.

Has the advantages that: (1) the invention carries out the microstructure forming on the surface of the metal foil through the thermal coupling effect generated by laser ablation of the sacrificial layer, has no cutting force generated by a cutter and no pollution problem caused by chemical reaction, and has the processing characteristics of environmental protection and no cutter abrasion.

(2) Compared with the traditional method, the laser continuous processing method for preparing the flexible metal micromold has the advantages of less procedures, no need of an ultra-precise machine tool and a cutter, small equipment investment and simple process.

(3) The invention combines the roller to continuously transmit and recover the sacrificial layer and the restraint layer, and can realize large-area and high-efficiency processing of the flexible metal micromold.

Drawings

FIG. 1 is a schematic structural diagram of a laser continuous processing device for a microstructure on a metal foil surface.

Detailed Description

The invention is further explained below with reference to the drawings.

A manufacturing method of a flexible metal micromold for hot stamping comprises the following steps:

step 1: and the metal foil is annealed, so that the internal stress is eliminated, the hardness is reduced, and the processing manufacturability of subsequent laser processing is improved. Wherein the metal foil can be aluminum foil, copper foil, stainless steel foil, nickel foil and other metal films, the thickness is not more than 200 μm, the annealing temperature is higher than the recrystallization temperature of the metal foil and lower than 0.7 times of the melting point, and the annealing time is not less than 20 min.

Step 2: and processing the annealed metal foil by adopting a metal foil surface microstructure laser continuous processing device, and processing one surface of the metal foil to obtain the microstructure required by the metal micromold.

As shown in FIG. 1, the laser continuous processing device for the microstructure on the surface of the metal foil comprises a laser module and a material transmission module. The laser processing module comprises a pulse laser controller 1, a pulse laser generator 2 and a beam shaping device 3. The material transmission module comprises a bottom lifting platform 8 and a top lifting platform 5, wherein a primary mould 7 is fixed on the bottom lifting platform 8, and a transparent transmission layer 4 is fixed on the top lifting platform 5. One side of the bottom lifting platform 8 is provided with a first tensioning roller 13, a first unreeling roller 11 wound with a sacrificial layer 12 and a second unreeling roller 16 wound with a metal foil 17, and the other side of the bottom lifting platform 8 is provided with a second tensioning roller 14, a first reeling roller 15 for recycling the sacrificial layer 12 and a second reeling roller 18 for recycling the metal foil 17. The sacrificial layer 12 and the metal foil 17 are passed between the master 7 and the transparent transfer layer 4 after being laminated and tensioned by a first tensioning roller 13 and a second tensioning roller 14.

The laser module is positioned above the top lifting frame 5 and is right opposite to the transparent transmission layer 4, and the width of the laser pulse emitted by the pulse laser generator 2 is not less than 1 ps. The transparent transmission layer 4 is glass having a thickness of not less than 1 mm. The sacrificial layer 12 is a metal film with the thickness less than 0.2mm and the upper surface covered with black paint. The master mould 7 may be of metal, plastic or other material and has a microstructure on its upper surface, the shape of which is opposite to that of the desired metal micromold.

The processing process comprises 4 steps, namely clamping, processing, separating and transmitting. Firstly, the controller 10 controls the two motors 9 to drive the bottom lifting platform 8 and the top lifting platform 5 to move towards each other, the top lifting platform 5 drives the transparent transmission layer 4 to move downwards, and the bottom lifting platform 8 drives the original mould 7 to move upwards, so that the sacrificial layer 12 and the metal foil 17 are clamped. Then, the pulse laser controller 1 controls the pulse laser generator 2 to emit pulse laser beams, the laser beams pass through the transparent transmission layer 4 after passing through the beam shaping device 3 and act on the surface of the sacrificial layer 12, and the thermal coupling effect generated in the interaction process of the laser and the sacrificial layer 12 enables the lower surface of the metal foil 17 to obtain a microstructure opposite to that of the master 7. And thirdly, the controller 10 controls the two motors 9 to separate the bottom lifting platform 8 from the top lifting platform 5, the top lifting platform 5 drives the transparent transmission layer 4 to move upwards, and the bottom lifting platform 8 drives the original mold 7 to move downwards, so that the separation of the transparent transmission layer 4 and the original mold 7 is realized. Finally, the controller 10 controls the rolling roller 15 and the rolling roller 18 to rotate, the rotation of the rolling roller 15 enables the sacrificial layer 12 to be released from the unreeling roller 11, sequentially pass through the tensioning roller 13 and the tensioning roller 14, and be recovered in the rolling roller 15; the rotation of the winding roller 18 causes the metal foil 17 to be discharged from the unwinding roller 16, sequentially pass through the tension roller 13, the tension roller 14 and be recovered to the winding roller 18. The four processes are repeated, and the laser continuous processing of the surface microstructure of the metal foil 17 can be realized.

And step 3: and annealing the processed metal foil with the microstructure again to remove residual stress generated in the metal foil due to processing. The annealing temperature is lower than the recrystallization temperature of the metal foil and higher than 0.2 times of the melting point, and the annealing time is not less than 20 min.

And 4, step 4: and combining a thermoplastic plastic film or a thermosetting plastic film with the thickness of not more than 1mm with the unstructured side of the metal foil to obtain the flexible metal micromold for hot stamping, wherein the plastic film can be PI, PDMS and the like.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.