CN117484745B - Piezoelectric copolymer thick film forming die and processing mode - Google Patents

Abstract

The application discloses a piezoelectric copolymer thick film forming die and a processing mode, wherein a forming bottom surface, a forming peripheral surface and a forming top surface are all provided with hard metal coatings, the surface roughness of the hard metal coatings is Ra less than or equal to 0.02, the flatness of the hard metal coatings on the forming bottom surface is better than 0.02mm, the flatness of the hard metal coatings on the forming top surface is better than 0.02mm, and the parallelism of the hard metal coatings on the forming bottom surface and the hard metal coatings on the forming top surface is better than 0.02 mm; according to the piezoelectric copolymer thick film forming die and the processing mode, through the cross section shape setting and the height setting of the concave die cavity, piezoelectric copolymer thick films of different types can be realized; the hardness, wear resistance, temperature resistance, corrosion resistance and other performances of the lower die and the upper die are improved by utilizing the hard metal coating, and the risk of polluting the piezoelectric copolymer thick film is reduced; the surface roughness of the hard metal coating is Ra less than or equal to 0.02, so that the stripping effect of the piezoelectric copolymer thick film after molding is excellent.

Description

Piezoelectric copolymer thick film forming mold and processing method

Technical Field

The invention relates to the field of piezoelectric film forming, and in particular to a piezoelectric copolymer thick film forming die and a processing method.

Background Art

Piezoelectric copolymer films have unique piezoelectric and mechanical properties and are widely used in various fields. During the manufacturing process, the polymer film is combined with a conductive material to give it good flexibility and plasticity. Under the action of external pressure, the piezoelectric copolymer film will generate voltage, thereby realizing the conversion of mechanical energy into electrical energy. This material plays an increasingly important role in the fields of smart sensors, energy harvesting, sound control, medical devices, etc. With the continuous advancement of technology and the expansion of application fields, piezoelectric copolymer films will be more widely used and promoted.

At present, the commonly used plastic film forming method is mainly extrusion molding. However, due to the sudden change in the temperature of the copolymer film during the extrusion cooling process, the surface will bend and uneven. Therefore, the extrusion molding process cannot guarantee the flatness of the piezoelectric copolymer thick film, and the risk of thickness non-uniformity is also relatively large. The surface of conventional ordinary metal molds is easily corroded by resin materials under high temperature and high pressure, causing them to fall off, thereby contaminating the copolymer resin raw materials and causing polarization breakdown of the copolymer thick film under high electric fields.

Summary of the invention

The main purpose of the present invention is to provide a piezoelectric copolymer thick film molding mold and processing method, aiming to solve the risks of uneven bending and uneven thickness in the current piezoelectric copolymer film processing method. At the same time, the surface of the metal mold is easily corroded by the resin material under high temperature and high pressure, causing it to fall off, thereby causing polarization breakdown of the copolymer thick film under high electric field.

In order to achieve the above object, the present invention provides a piezoelectric copolymer thick film forming mold for forming the piezoelectric copolymer thick film having a thickness greater than 0.1 mm, comprising:

A lower die made of metal material, with at least one concave die cavity disposed on the upper surface, the bottom of the concave die cavity being the molding bottom surface, and the peripheral wall of the concave die cavity being the molding peripheral surface;

An upper die made of metal material can be detachably stacked on the lower die, and the area of the lower surface of the upper die corresponding to the concave die cavity is the molding top surface;

Among them, the molding bottom surface, the molding peripheral surface and the molding top surface are all provided with a hard metal coating, and the surface roughness of the hard metal coating is Ra≤0.02, the flatness of the hard metal coating on the molding bottom surface is better than 0.02 mm, the flatness of the hard metal coating on the molding top surface is better than 0.02 mm, and the parallelism of the hard metal coating on the molding bottom surface and the hard metal coating on the molding top surface is better than 0.02 mm.

Furthermore, the number of the die cavities is multiple, and they are densely arranged on the plane in the form of equilateral triangle arrangement units or square arrangement units, wherein any one of the die cavities is connected to the multiple die cavities adjacent to it through a connecting channel, wherein the length of the connecting channel is between 0.1 and 3 mm, and the cross-section of the connecting channel is between 1 and 3 square millimeters.

Furthermore, the lower mold includes a mesh body and a lower plate body, the mesh body is stacked on the lower plate body, a plurality of cavities are arranged on the mesh body, and the lower plate body has the same structure as that of the upper mold.

Furthermore, each of the cavities on the upper surface of the mesh body is surrounded by a high-smoothness circle to form a first sealing area, and the surface roughness of the first sealing area is Ra≤0.02; the area on the lower surface of the upper mold corresponding to the die cavity and the high-smoothness circle is a second sealing area, and the surface roughness of the second sealing area is Ra≤0.02, wherein the surface roughness of the lower surface of the mesh body and the upper surface of the lower plate body are Ra≤0.02, the surface roughness of the upper surface of the lower mold except the first sealing area is greater than 1, and the surface roughness of the lower surface of the upper mold except the second sealing area is greater than 1.

Furthermore, each of the die cavities on the upper surface of the lower die is surrounded by a high-smoothness circle to form a first sealing area, and the surface roughness of the first sealing area is Ra≤0.02; the area on the lower surface of the upper die corresponding to the die cavity and the high-smoothness circle is a second sealing area, and the surface roughness of the second sealing area is Ra≤0.02, wherein the surface roughness Ra of the area on the upper surface of the lower die except the first sealing area is greater than 1, and the surface roughness Ra of the area on the lower surface of the upper die except the second sealing area is greater than 1.

Furthermore, the width of the high-smoothness circle is between 2 and 10 mm.

Furthermore, a plurality of first through hole groups are provided on the upper mold, the first through hole group includes a plurality of first through holes, the first through hole group is arranged corresponding to the position of the high smoothness circle, and the first through holes are arranged in the middle of the high smoothness circle in the width direction.

Furthermore, the material of the hard metal coating is selected from one of a hard chrome coating and a titanium nitride coating.

The present invention also provides a processing method for a piezoelectric copolymer thick film forming mold, which is applied to the above-mentioned piezoelectric copolymer thick film forming mold, comprising:

S1. Polishing the concave mold cavity on the lower mold;

S2, polishing the upper surface of the lower mold;

S3, roughening the upper surface of the lower mold except the first sealing area by electrochemical means;

S4, polishing the lower surface of the upper mold;

S5. Roughening the lower surface of the upper mold except the second sealing area by electrochemical means.

The present invention also provides a processing method for a piezoelectric copolymer thick film forming mold, which is applied to the above-mentioned piezoelectric copolymer thick film forming mold, comprising:

P1. Polish the upper surface of the lower plate;

P2. Polish the inner wall of the cavity on the mesh body;

P3, roughening the upper surface of the lower mold except the first sealing area by electrochemical method;

P4. Polish the lower surface of the upper mold;

P5. The lower surface of the upper mold except the second sealing area is roughened by electrochemical means.

The piezoelectric copolymer thick film forming mold and processing method provided by the present invention, the cross-sectional shape of the concave mold cavity is not limited to a circle, but can also be a rectangle or other shapes. By setting the cross-sectional shape of the concave mold cavity and the height setting, different types of piezoelectric copolymer thick films can be realized; the lower mold and the upper mold have good thermal conductivity and can achieve uniform heating; the hardness, wear resistance, temperature resistance and corrosion resistance of the lower mold and the upper mold are improved by using a hard metal coating, and the risk of contaminating the piezoelectric copolymer thick film is reduced; the surface roughness of the hard metal coating is Ra≤0.02, so the piezoelectric copolymer thick film has an excellent detachment effect after molding. The flatness of the hard metal coating on the molding bottom surface is better than 0.02 mm, and the flatness of the hard metal coating on the molding top surface is better than 0.02 mm, so the flatness of the surface of the piezoelectric copolymer thick film is improved; the parallelism of the hard metal coating on the molding bottom surface and the hard metal coating on the molding top surface is better than 0.02 mm, so the thickness of the piezoelectric copolymer thick film is uniform.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a piezoelectric copolymer thick film forming mold according to a first embodiment of the present invention (from an upper perspective);

FIG2 is a partial enlarged view of FIG1;

3 is a schematic diagram of a piezoelectric copolymer thick film forming mold according to a first embodiment of the present invention (from a lower viewing angle);

4 is a schematic diagram of a piezoelectric copolymer thick film forming mold according to a second embodiment of the present invention (from an upper perspective);

FIG5 is a partial enlarged view of FIG4;

6 is a schematic diagram of a piezoelectric copolymer thick film forming mold according to a second embodiment of the present invention (from a lower viewing angle);

7 is a schematic diagram of a mesh body in a piezoelectric copolymer thick film forming mold according to a third embodiment of the present invention;

8 is a schematic diagram of a lower plate in a piezoelectric copolymer thick film forming mold according to a third embodiment of the present invention;

9 is a schematic diagram of a lower mold in a piezoelectric copolymer thick film molding mold according to a third embodiment of the present invention;

10 is a schematic diagram of the processing steps of the piezoelectric copolymer thick film molding mold according to the fourth embodiment of the present invention;

FIG. 11 is a schematic diagram showing the steps of processing a piezoelectric copolymer thick film molding mold according to the fifth embodiment of the present invention.

The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings.

DETAILED DESCRIPTION

It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

Those skilled in the art will appreciate that, unless expressly stated otherwise, the singular forms "a", "an", "said", "above", and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements, units, modules, and/or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, units, modules, components, and/or groups thereof. It should be understood that when we refer to an element as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be intermediate elements. In addition, the "connection" or "coupling" used herein may include wireless connection or wireless coupling. The term "and/or" used herein includes all or any unit and all combinations of one or more associated listed items.

It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined as herein.

1 to 9, in one embodiment of the present invention, a piezoelectric copolymer thick film molding die is used to mold the piezoelectric copolymer thick film having a thickness greater than 0.1 mm, comprising:

The lower mold 100 is made of metal, and has at least one concave mold cavity 110 on its upper surface. The bottom of the concave mold cavity 110 is a molding bottom surface 111, and the peripheral wall of the concave mold cavity 110 is a molding peripheral surface 112.

The upper mold 200 made of metal material can be detachably stacked on the lower mold 100, and the area of the lower surface of the upper mold 200 corresponding to the concave mold cavity 110 is the molding top surface 210;

Among them, the molding bottom surface 111, the molding peripheral surface 112 and the molding top surface 210 are all provided with a hard metal coating, and the surface roughness of the hard metal coating is Ra≤0.02, the flatness of the hard metal coating on the molding bottom surface 111 is better than 0.02 mm, the flatness of the hard metal coating on the molding top surface 210 is better than 0.02 mm, and the parallelism of the hard metal coating on the molding bottom surface 111 and the hard metal coating on the molding top surface 210 is better than 0.02 mm.

In the prior art, the commonly used plastic film forming method is mainly extrusion molding. However, due to the sudden change in temperature of the copolymer film during the extrusion cooling process, the surface will bend and uneven. Therefore, the extrusion molding process cannot guarantee the flatness of the piezoelectric copolymer thick film, and the risk of thickness unevenness is also relatively large. The surface of conventional ordinary metal molds is easily corroded by the resin material under high temperature and high pressure, causing it to fall off, thereby contaminating the copolymer resin raw materials and causing polarization breakdown of the copolymer thick film under high electric fields.

In the present invention, the piezoelectric copolymer thick film forming mold is fixed in the up and down directions when in use, so a certain direction is indicated in an up and down manner. The piezoelectric copolymer thick film forming mold is used to form a piezoelectric copolymer thick film with a thickness greater than 0.1 mm. For a thinner film, the mold forming method of the present invention is not suitable.

The lower mold 100 is made of metal, and at least one concave mold cavity 110 is disposed on the upper surface of the lower mold 100. The bottom of the concave mold cavity 110 is a molding bottom surface 111, and the peripheral wall of the concave mold cavity 110 is a molding peripheral surface 112. When a plurality of concave mold cavities 110 are disposed on the lower mold 100, a structural relationship can also be formed between the concave mold cavities 110, which will be further described in subsequent embodiments.

The upper mold 200 is made of metal and can be detachably stacked on the lower mold 100 . The area on the lower surface of the upper mold 200 corresponding to the concave mold cavity 110 is a molding top surface 210 .

The cross-sectional shape of the concave mold cavity 110 is not limited to a circle, but can also be a rectangle or other shapes. By setting the cross-sectional shape and height of the concave mold cavity 110, different types of piezoelectric copolymer thick films can be achieved. The material selection of the lower mold 100 and the upper mold 200 is preferably a metal material with good thermal conductivity and a certain hardness, such as copper, brass, mold steel, etc.

The molding bottom surface 111, the molding peripheral surface 112 and the molding top surface 210 are all provided with a hard metal coating, and the surface roughness of the hard metal coating is Ra≤0.02, the flatness of the hard metal coating on the molding bottom surface 111 is better than 0.02 mm, the flatness of the hard metal coating on the molding top surface 210 is better than 0.02 mm, and the parallelism of the hard metal coating on the molding bottom surface 111 and the hard metal coating on the molding top surface 210 is better than 0.02 mm; it should be noted that if the surface roughness of the hard metal coating naturally meets the requirements, no subsequent processing is required, otherwise a subsequent polishing process step is required. The specific polishing process step can be mechanical polishing, chemical polishing or electrochemical polishing, or a combination of multiple polishing methods.

Hard metal coating is a process of covering a base surface with one or more layers of metal or alloy by electroplating or chemical deposition methods. This coating can significantly improve the mechanical and thermal properties of the base surface. The most common are hard chrome coating and titanium nitride coating. Hard chrome coating is a process of depositing one or more layers of chromium alloy on a metal surface by electroplating, which has high hardness, good wear resistance and corrosion resistance, while titanium nitride coating is a process of forming a titanium nitride film on a metal surface by chemical deposition, which has high hardness, good corrosion resistance and oxidation resistance. In addition to hard chrome coating and titanium nitride coating, there are other types of hard metal coatings, such as chromium nitride coating, tungsten carbide coating, etc. These coatings have different characteristics and are suitable for different application scenarios. While the possibility of corrosion of the forming mold is reduced by hard metal coating, the structural shape accuracy of the lower mold 100 and the upper mold 200 itself is high. Hard metal coating is used to improve the hardness, wear resistance, temperature resistance and corrosion resistance of the lower mold 100 and the upper mold 200.

At the same time, if the surface roughness of the hard metal coating is Ra≤0.02, the piezoelectric copolymer thick film has an excellent release effect after molding. If the flatness of the hard metal coating on the molding bottom surface 111 is better than 0.02 mm, and the flatness of the hard metal coating on the molding top surface 210 is better than 0.02 mm, the flatness of the surface of the piezoelectric copolymer thick film is improved. If the parallelism of the hard metal coating on the molding bottom surface 111 and the hard metal coating on the molding top surface 210 is better than 0.02 mm, the thickness of the piezoelectric copolymer thick film is uniform.

In the upper mold 200 and the lower mold 100, a local area can be formed into a low roughness and a local area can be formed into a high roughness. The above processing methods of different roughness can be various. For example, the overall low roughness processing is completed first, and then the local roughening treatment is performed. The metal surface is roughened by chemical or physical methods. The physical method is to make the metal surface plastically deformed by grinding, shot peening, rolling, etc., so that it becomes rough; electrochemical roughening is to form a rough oxide film or electroplating layer on the metal surface by anodizing or cathode plating on the metal surface; or the overall roughness can be made high, and the local low roughness treatment (such as local polishing) can be performed.

When using:

First, fill the P (VDF-TrFE) ferroelectric copolymer powder into the concave mold cavity 110, and then put the upper mold 200 and the lower mold 100 into a flat-plate vulcanizer after the upper mold 200 and the lower mold 100 are closed. The molding mold is heated by the flat-plate vulcanizer, such as maintaining 190 degrees Celsius for eight minutes to melt the powder. After the raw material powder is completely melted, pressure is applied (pressure of 100 MPa for 1 minute) (the main function is to ensure the fit between the upper mold 200 and the lower mold 100), and then the pressure is released, the mold is taken out, and it is first placed in a 125-degree Celsius oven for 1 hour, and then naturally cooled to room temperature at room temperature, and finally the molded piezoelectric copolymer thick film is taken out.

In summary, the cross-sectional shape of the concave mold cavity 110 is not limited to a circle, but can also be a rectangle or other shapes. By setting the cross-sectional shape and height of the concave mold cavity 110, different types of piezoelectric copolymer thick films can be realized; the lower mold 100 and the upper mold 200 have good thermal conductivity and can achieve uniform heating; the hard metal coating is used to improve the hardness, wear resistance, temperature resistance and corrosion resistance of the lower mold 100 and the upper mold 200, and reduce the risk of contaminating the piezoelectric copolymer thick film; the surface roughness of the hard metal coating is Ra≤0.02, so the piezoelectric copolymer thick film has an excellent detachment effect after molding. The flatness of the hard metal coating on the molding bottom surface 111 is better than 0.02 mm, and the flatness of the hard metal coating on the molding top surface 210 is better than 0.02 mm, so the flatness of the surface of the piezoelectric copolymer thick film is improved; the parallelism of the hard metal coating on the molding bottom surface 111 and the hard metal coating on the molding top surface 210 is better than 0.02 mm, so the thickness of the piezoelectric copolymer thick film is uniform.

Referring to Figures 4 to 6, in one embodiment, the number of the die cavities 110 is multiple, and they are densely arranged on the plane in the form of equilateral triangle arrangement units or square arrangement units, wherein any one of the die cavities 110 is connected to the multiple die cavities 110 adjacent to it through a connecting channel 300, wherein the length of the connecting channel 300 is between 0.1 and 3 mm, and the cross-section of the connecting channel 300 is between 1 and 3 square millimeters.

In the present embodiment, the processing of the piezoelectric copolymer thick film is carried out through the die cavity 110. After adding the raw material powder in the die cavity 110, the die is closed and heated to complete the molding process. In the present embodiment, considering the different amounts of raw material powder added in each die cavity 110, the molding pressure will be different, and the parameters of the piezoelectric copolymer thick film finally formed are uneven. Then the multiple die cavities 110 on the lower mold 100 are connected, and the connection between the die cavity 110 and the nearby die cavity 110 is made to average the pressure. The length of the connecting channel 300 is between 0.1 and 3 mm. If the length of the connecting channel 300 is too long, it will affect the interaction between the raw materials in the die cavity 110 on the one hand, and on the other hand, it will also cause the raw materials to be stored in the connecting channel 300 and affect the accuracy of the amount of raw materials in the die cavity 110. The cross section of the connecting channel 300 is between 1 and 3 square millimeters. Combined with its length, the connecting channel 300 can reduce the deviation of the raw material quantity under the premise of satisfying the communication. In particular, the length of the connecting channel 300 can also be considered in the injection amount of the raw material powder, thereby improving the accuracy of molding. The smaller the size of the concave mold cavity 110, the more uniform the molding. After the molding is completed, the connected piezoelectric copolymer thick film units are divided to achieve a balance between efficiency and quality.

7 to 9 , in one embodiment, the lower mold 100 includes a mesh body 120 and a lower plate body 130 , the mesh body 120 is stacked on the lower plate body 130 , a plurality of cavities 121 are provided on the mesh body 120 , and the lower plate body 130 has the same structure as the upper mold 200 .

In this embodiment, since the surface roughness of the bottom of the concave mold cavity 110 has strict requirements, and due to its special shape, the difficulty of surface processing is relatively high. In this embodiment, the lower mold 100 is divided into a mesh body 120 and a lower plate body 130. When the mesh body 120 and the lower plate body 130 are combined, the cavity 121 is combined with the lower plate body 130 to form the concave mold cavity 110. By surface processing the upper surface of the lower plate body 130, when the mesh body 120 and the lower plate body 130 are combined, the bottom of the concave mold cavity 110 is a surface that meets the roughness. In particular, the structure of the lower plate body 130 is consistent with that of the upper mold 200, so that the processing technology of the lower surface of the upper mold 200 and the upper surface of the lower plate body 130 can be consistent. The inner wall of the cavity hole 121 on the corresponding mesh body 120 can also be surface processed to achieve an appropriate roughness. The fixing method between the mesh body 120 and the lower plate body 130 can be various, either mechanically or by welding. It is particularly noted that when the thickness of the piezoelectric copolymer thick film is large, the thickness of the mesh body 120 is large, which is convenient for processing; if the thickness of the piezoelectric copolymer thick film is small, then a protruding structure may need to be set at the corresponding position of the lower plate body 130 and extend into the cavity 121 to ensure that the processing thickness of the mesh body 120 is actually operational.

Referring to Figures 7 to 9, in one embodiment, each of the cavities 121 on the upper surface of the mesh body 120 is surrounded by a high-smoothness ring 113 to form a first sealing area, and the surface roughness of the first sealing area is Ra≤0.02; the area on the lower surface of the upper mold 200 corresponding to the die cavity 110 and the high-smoothness ring 113 is a second sealing area, and the surface roughness of the second sealing area is Ra≤0.02, wherein the surface roughness of the lower surface of the mesh body 120 and the upper surface of the lower plate body 130 is Ra≤0.02, the surface roughness Ra of the upper surface of the lower mold 100 except the first sealing area is greater than 1, and the surface roughness Ra of the lower surface of the upper mold 200 except the second sealing area is greater than 1.

In this embodiment, first, the high smoothness ring 113 surrounds the die cavity 110. The first sealing area formed by the multiple high smoothness rings 113 surrounds the multiple die cavities 110. The surface roughness of the first sealing area is Ra≤0.02. The area on the lower surface of the upper mold 200 corresponding to the die cavity 110 and the high smoothness ring 113 is the second sealing area. The surface roughness of the second sealing area is Ra≤0.02. When the upper mold 200 is combined with the lower mold 100, the first sealing area is combined with the second sealing area. At this time, the excellent fit between the two can form an excellent sealing effect (the combination of air pressure and high flatness). It should be noted that when the concave mold cavities 110 are connected to each other, the first sealing area is a plurality of dispersed ring-shaped structures; when the concave mold cavities 110 are connected with a hooking channel 300, a high smoothness channel (as a part of the first sealing area) can also be set on the upper surface of the lower mold 100 and on both sides of the length direction of the hooking channel 300, so as to form a sealing effect at the hooking channel 300, and at this time, the first sealing area is a structure connected to form an integral whole. In particular, the surface roughness of the upper surface of the lower mold 100 except the position of the first sealing area is relatively large, and the surface roughness of the lower surface of the upper mold 200 except the second sealing area is relatively large, so the difficulty of separating the lower mold 100 from the upper mold 200 will not be reduced. At the same time, the surface roughness Ra of the lower surface of the mesh body 120 and the upper surface of the lower plate body 130 is ≤ 0.02, so the contact sealing effect of the mesh body 120 and the lower plate body 130 is excellent, which is conducive to the piezoelectric copolymer thick film forming process.

Referring to Figures 4 to 6, in one embodiment, each of the concave mold cavities 110 on the upper surface of the lower mold 100 is surrounded by a high-smoothness ring 113 to form a first sealing area, and the surface roughness of the first sealing area is Ra≤0.02. The area on the lower surface of the upper mold 200 corresponding to the concave mold cavity 110 and the high-smoothness ring 113 is a second sealing area, and the surface roughness of the second sealing area is Ra≤0.02, wherein the surface roughness Ra of the upper surface of the lower mold 100 except the first sealing area is greater than 1, and the surface roughness Ra of the lower surface of the upper mold 200 except the second sealing area is greater than 1.

In this embodiment, first, the high smoothness ring 113 surrounds the die cavity 110. The first sealing area formed by the multiple high smoothness rings 113 surrounds the multiple die cavities 110. The surface roughness of the first sealing area is Ra≤0.02. The area on the lower surface of the upper mold 200 corresponding to the die cavity 110 and the high smoothness ring 113 is the second sealing area. The surface roughness of the second sealing area is Ra≤0.02. When the upper mold 200 is combined with the lower mold 100, the first sealing area is combined with the second sealing area. At this time, the excellent fit between the two can form an excellent sealing effect (the combination of air pressure and high flatness). It should be noted that when the concave mold cavities 110 are connected to each other, the first sealing area is a plurality of dispersed ring-shaped structures; when the concave mold cavities 110 are connected with a hooking channel 300, a high smoothness channel (as a part of the first sealing area) can also be set on the upper surface of the lower mold 100 and on both sides of the length direction of the hooking channel 300, so as to form a sealing effect at the hooking channel 300, and the first sealing area is connected to form an integral structure. In particular, the surface roughness of the upper surface of the lower mold 100 except the position of the first sealing area is relatively large, and the surface roughness of the lower surface of the upper mold 200 except the second sealing area is relatively large, so the difficulty of separating the lower mold 100 from the upper mold 200 will not be reduced.

In one embodiment, the width of the high smoothness circle 113 is between 2 and 10 mm.

In this embodiment, the appropriate width range of the high smoothness ring 113 is given, and the size of the corresponding second sealing area is also limited. If the width of the high smoothness ring 113 is too large, the difficulty of processing will increase, and the difficulty of mold separation will also increase; if the width of the high smoothness ring 113 is too small, the sealing effect will be reduced. The width of the high smoothness ring 113 is more preferably between 2 and 10 mm.

In one embodiment, a plurality of first through hole groups are provided on the upper mold 200 , the first through hole group includes a plurality of first through holes, the first through hole group is arranged corresponding to the position of the high smoothness ring 113 , and the first through holes are arranged in the middle of the high smoothness ring 113 in the width direction.

In this embodiment, due to the existence of the first sealing area and the second sealing area, the sealing effect between the upper mold 200 and the lower mold 100 at the position of the concave mold cavity 110 is relatively superior, which also causes the difficulty of separating the upper mold 200 and the lower mold 100. In this embodiment, the first through hole group is introduced to facilitate the entry of air during the mold separation process (air can even be pressed into the first through hole), thereby reducing the difficulty of separating the upper mold 200 and the lower mold 100. The first through hole is set in the middle of the width direction of the high smoothness circle 113, which can facilitate the entry of air while ensuring the sealing effect.

In one embodiment, the material of the hard metal coating is selected from one of a hard chrome coating and a titanium nitride coating.

In this embodiment, the material selection of the hard metal coating is given. In fact, there are many choices of hard metal coatings, but hard chromium coatings and titanium nitride coatings are widely used. At the same time, the hardness, wear resistance, temperature resistance and corrosion resistance can meet the requirements of the piezoelectric copolymer thick film forming process.

10 , the present invention further provides a processing method for a piezoelectric copolymer thick film molding mold, which is applied to the above-mentioned piezoelectric copolymer thick film molding mold, comprising:

S1, polishing the concave mold cavity 110 on the lower mold 100;

S2, polishing the upper surface of the lower mold 100;

S3, roughening the upper surface of the lower mold 100 except the first sealing area by electrochemical means;

S4, polishing the lower surface of the upper mold 200;

S5. Roughening the lower surface of the upper mold 200 except the second sealing area is performed in an electrochemical manner.

In this embodiment, since the first sealing area and the second sealing area have more small width areas, it is difficult to achieve roughening treatment by mechanical means; similarly, it is also difficult to polish this position. Therefore, the processing logic is to polish a large area first, and then electrochemically roughen a small area, so as to complete the formation of differences in the roughness of each area of the piezoelectric copolymer thick film molding mold. Specifically, the order of polishing the concave mold cavity 110 on the lower mold 100 and polishing the upper surface of the lower mold 100 can be reversed according to actual conditions. The specific polishing method can be mechanical polishing, chemical polishing or electrochemical polishing, etc., or a combination of multiple polishing methods. In this embodiment, mechanical polishing assisted by polishing powder is used.

11 , the present invention further provides a method for processing a piezoelectric copolymer thick film molding die, which is applied to the above-mentioned piezoelectric copolymer thick film molding die, comprising:

P1. Polishing the upper surface of the lower plate 130;

P2. Polishing the inner wall of the cavity hole 121 of the mesh body 120;

P3, roughening the upper surface of the lower mold 100 except the first sealing area by electrochemical means;

P4, polishing the lower surface of the upper mold 200;

P5. Roughening the lower surface of the upper mold 200 except the second sealing area is performed by electrochemical means.

In this embodiment, considering that the entire cavity 110 has roughness requirements, in fact, when the cavity 110 is an integrated structure, the polishing process of the cavity 110 is difficult to perform. The lower mold 100 is divided into a mesh body 120 and a lower plate body 130. When the mesh body 120 and the lower plate body 130 are combined, the cavity 121 is combined with the lower plate body 130 to form the cavity 110. By surface processing the upper surface of the lower plate body 130, when the mesh body 120 and the lower plate body 130 are combined, the bottom of the cavity 110 is a surface that meets the roughness. In particular, the structure of the lower plate body 130 is consistent with that of the upper mold 200, so that the processing technology of the lower surface of the upper mold 200 can be consistent with the processing technology of the upper surface of the lower plate body 130. The inner wall of the cavity hole 121 on the corresponding mesh body 120 is also surface processed to achieve an appropriate roughness. Since the first sealing area and the second sealing area have many small width areas, it is difficult to achieve roughening by mechanical means; similarly, it is also difficult to polish this position. Therefore, the processing logic is to polish a large area first, and then electrochemically roughen a small area, so as to achieve the difference in roughness of each area of the piezoelectric copolymer thick film molding mold.

In summary, in the piezoelectric copolymer thick film molding mold and processing method provided by the present invention, the cross-sectional shape of the concave mold cavity 110 is not limited to a circle, but can also be a rectangle or other shapes. By setting the cross-sectional shape and height of the concave mold cavity 110, different types of piezoelectric copolymer thick films can be achieved; the lower mold 100 and the upper mold 200 have good thermal conductivity and can achieve uniform heating; the hard metal coating is used to improve the hardness, wear resistance, temperature resistance and corrosion resistance of the lower mold 100 and the upper mold 200, thereby reducing the risk of contaminating the piezoelectric copolymer thick film; the surface roughness of the hard metal coating is Ra≤0.02, so the release effect of the piezoelectric copolymer thick film after molding is excellent. The flatness of the hard metal coating on the molding bottom surface 111 is better than 0.02 mm, and the flatness of the hard metal coating on the molding top surface 210 is better than 0.02 mm, so the flatness of the surface of the piezoelectric copolymer thick film is improved; the parallelism of the hard metal coating on the molding bottom surface 111 and the hard metal coating on the molding top surface 210 is better than 0.02 mm, so the thickness of the piezoelectric copolymer thick film is uniform.

The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims (8)

1. A piezoelectric copolymer thick film forming mold, used for forming the piezoelectric copolymer thick film with a thickness greater than 0.1 mm, characterized in that it comprises: A lower mold (100) made of metal material has at least one concave mold cavity (110) disposed on its upper surface, the bottom of the concave mold cavity (110) being a molding bottom surface (111), and the peripheral wall of the concave mold cavity (110) being a molding peripheral surface (112); An upper mold (200) made of metal material can be detachably stacked on the lower mold (100), and the area of the lower surface of the upper mold (200) corresponding to the concave mold cavity (110) is a molding top surface (210); The molding bottom surface (111), the molding peripheral surface (112) and the molding top surface (210) are all provided with a hard metal coating, and the surface roughness of the hard metal coating is Ra≤0.02, the flatness of the hard metal coating on the molding bottom surface (111) is better than 0.02 mm, the flatness of the hard metal coating on the molding top surface (210) is better than 0.02 mm, and the parallelism of the hard metal coating on the molding bottom surface (111) and the hard metal coating on the molding top surface (210) is better than 0.02 mm; The lower mold (100) comprises a mesh body (120) and a lower plate body (130), the mesh body (120) is stacked on the lower plate body (130), a plurality of cavities (121) are provided on the mesh body (120), and the lower plate body (130) has the same structure as the upper mold (200); On the upper surface of the mesh body (120), each cavity (121) is surrounded by a high-smoothness ring (113) to form a first sealing area, and the surface roughness of the first sealing area is Ra≤0.02; the area on the lower surface of the upper mold (200) corresponding to the die cavity (110) and the high-smoothness ring (113) is the second sealing area, and the surface roughness of the second sealing area is Ra≤0.02, wherein the surface roughness of the lower surface of the mesh body (120) and the upper surface of the lower plate body (130) is Ra≤0.02, the surface roughness Ra of the upper surface of the lower mold (100) except the first sealing area is greater than 1, and the surface roughness Ra of the lower surface of the upper mold (200) except the second sealing area is greater than 1. 2. The piezoelectric copolymer thick film forming mold according to claim 1 is characterized in that the number of the concave mold cavities (110) is multiple, and they are closely arranged on the plane in the form of equilateral triangle arrangement units or square arrangement units, wherein any one of the concave mold cavities (110) is connected to the multiple concave mold cavities (110) adjacent to it through a connecting channel (300), wherein the length of the connecting channel (300) is between 0.1 and 3 mm, and the cross-section of the connecting channel (300) is between 1 and 3 square millimeters. 3. A processing method for a piezoelectric copolymer thick film forming mold, applied to the piezoelectric copolymer thick film forming mold according to claim 1, characterized in that it comprises: P1. Polishing the upper surface of the lower plate (130); P2. Polishing the inner wall of the cavity hole (121) on the mesh body (120); P3, roughening the upper surface of the lower mold (100) except the first sealing area by electrochemical means; P4, polishing the lower surface of the upper mold (200); P5. Roughening the lower surface of the upper mold (200) except the second sealing area is performed by electrochemical means. 4. A piezoelectric copolymer thick film molding die, used for molding the piezoelectric copolymer thick film with a thickness greater than 0.1 mm, characterized in that it comprises: A lower mold (100) made of metal material has at least one concave mold cavity (110) disposed on its upper surface, the bottom of the concave mold cavity (110) being a molding bottom surface (111), and the peripheral wall of the concave mold cavity (110) being a molding peripheral surface (112); An upper mold (200) made of metal material can be detachably stacked on the lower mold (100), and the area of the lower surface of the upper mold (200) corresponding to the concave mold cavity (110) is a molding top surface (210); The molding bottom surface (111), the molding peripheral surface (112) and the molding top surface (210) are all provided with a hard metal coating, and the surface roughness of the hard metal coating is Ra≤0.02, the flatness of the hard metal coating on the molding bottom surface (111) is better than 0.02 mm, the flatness of the hard metal coating on the molding top surface (210) is better than 0.02 mm, and the parallelism of the hard metal coating on the molding bottom surface (111) and the hard metal coating on the molding top surface (210) is better than 0.02 mm; On the upper surface of the lower mold (100), each of the corresponding concave mold cavities (110) is surrounded by a high-smoothness ring (113) to form a first sealing area, and the surface roughness of the first sealing area is Ra≤0.02. The area on the lower surface of the upper mold (200) corresponding to the concave mold cavity (110) and the high-smoothness ring (113) is a second sealing area, and the surface roughness of the second sealing area is Ra≤0.02. The surface roughness Ra of the upper surface of the lower mold (100) except the first sealing area is greater than 1, and the surface roughness Ra of the lower surface of the upper mold (200) except the second sealing area is greater than 1. 5. The piezoelectric copolymer thick film forming mold according to claim 4, characterized in that the width of the high smoothness circle (113) is between 2 and 10 mm. 6. The piezoelectric copolymer thick film molding mold according to claim 4 is characterized in that a plurality of first through hole groups are arranged on the upper mold (200), the first through hole group includes a plurality of first through holes, the first through hole group is arranged corresponding to the position of the high smoothness circle (113), and the first through holes are arranged in the middle of the width direction of the high smoothness circle (113). 7 . The piezoelectric copolymer thick film forming mold according to claim 4 , wherein the material of the hard metal coating is selected from one of a hard chrome coating and a titanium nitride coating. 8. A processing method for a piezoelectric copolymer thick film forming mold, applied to the piezoelectric copolymer thick film forming mold according to claim 4, characterized in that it comprises: S1, polishing the concave mold cavity (110) on the lower mold (100); S2, polishing the upper surface of the lower mold (100); S3, roughening the upper surface of the lower mold (100) except the first sealing area by electrochemical means; S4, polishing the lower surface of the upper mold (200); S5. Roughening the lower surface of the upper mold (200) except the second sealing area is performed in an electrochemical manner.