阅读说明：本技术 带有力敏薄膜的条带式柔性线阵压力传感器、智能工装夹具及力敏薄膜制备方法 (Strip-type flexible linear array pressure sensor with force-sensitive film, intelligent tool fixture and force-sensitive film preparation method ) 是由 杨俊� 欧雷 胡宁 徐龙 谢磊 台国君 魏大鹏 于 2021-05-21 设计创作，主要内容包括：本发明公开带有力敏薄膜的条带式柔性线阵压力传感器、智能工装夹具及力敏薄膜制备方法。本发明增强了条带式柔性线阵压力传感器的压敏特性,进而避免各部位的受力不均匀所导致的加工工件曲面厚度不一致。(The invention discloses a strip-type flexible linear array pressure sensor with a force-sensitive film, an intelligent tool fixture and a force-sensitive film preparation method. The invention enhances the pressure-sensitive characteristic of the strip-type flexible linear array pressure sensor, thereby avoiding the inconsistency of the curved surface thickness of the processed workpiece caused by uneven stress of each part.)

1. The utility model provides a flexible linear array pressure sensor of strip formula which characterized in that: the flexible substrate (2) and a plurality of pressure sensor linear array units (101) are included.

The flexible substrate (2) is constructed with a plurality of micro-nano structures;

a plurality of pressure sensor linear array units (101) are integrated on the surface of the flexible substrate (2);

the surface of each pressure sensor linear array unit (101) is provided with a stress conduction contact (102);

the pressure sensor linear array unit (101) comprises interdigital electrodes and a semi-conformal micro-nano force sensitive film which are integrated on the surface of the flexible substrate (2);

the semi-conformal micro-nano force-sensitive film comprises a micro-nano conformal conducting layer (301) and a semi-conformal piezoelectric tunneling layer (302);

the micro-nano conformal conducting layer (301) covers the surface of the micro-nano structure;

the semi-conformal piezoelectric tunneling layer (302) partially covers the surface of the micro-nano conformal conducting layer (301).

2. The strip flexible linear array pressure sensor according to claim 1, wherein: the area of the stress conduction contact (102) is smaller than that of the pressure sensor linear array unit (101).

3. The strip flexible linear array pressure sensor according to claim 1, wherein: the stress conduction contact (102) is made of elastic material;

the flexible substrate (2) is made of silicon rubber, polyurethane elastomer and Eco-Flex;

the material of the micro-nano conformal conducting layer (301) comprises graphene, a graphene nanowall, a carbon nanotube, carbon black, a conducting polymer and metal;

the material of the semi-conformal piezoelectric tunneling layer (302) comprises PVDF, PVDF: TrFE, PVDF-HFP.

4. The strip flexible linear array pressure sensor according to claim 1, wherein: the semi-conformal piezoelectric tunneling layer (302) is subjected to a high voltage polarization process.

5. The strip flexible linear array pressure sensor according to claim 1, wherein: the semi-conformal piezoelectric tunneling layer (302) does not wrap the top of the micro-nano conformal conducting layer (301).

6. The strip flexible linear array pressure sensor according to claim 1, wherein: the pattern of the micro-nano structure comprises a pyramid, a column and a hemisphere.

7. An intelligent tool clamp with the strip-type flexible linear array pressure sensor as claimed in any one of claims 1 to 6, which is characterized in that: the device comprises a plurality of strip-type flexible linear array pressure sensors (1) and a metal tool clamp (4);

the inner surface of the metal tool clamp (4) is matched with the curved surface contour of the workpiece to be machined;

the metal tool clamp (4) is used for fixing a workpiece to be machined;

the lower surface of the strip-type flexible linear array pressure sensor (1) is attached to the inner surface of the metal tool clamp (4), and the upper surface of the strip-type flexible linear array pressure sensor is in contact with a workpiece to be processed;

in the processing process of a workpiece to be processed, the strip-type flexible linear array pressure sensor (1) detects the pressure applied to each part of the surface of the workpiece to be processed in real time.

8. The intelligent tool clamp with the strip-type flexible linear array pressure sensor as claimed in claim 7, wherein: the strip-type flexible linear array pressure sensor (1) feeds the detected pressure back to an external processing equipment control system; the processing equipment control system is prestored with a pressure threshold value; and the processing equipment control system compares the received pressure with a pressure threshold value and adjusts the processing parameters in real time according to the comparison result.

9. The intelligent tool clamp with the strip-type flexible linear array pressure sensor as claimed in claim 7, wherein: a plurality of strip-type flexible linear array pressure sensors (1) are attached to the inner surface of the metal tool clamp (4) one by one.

10. A preparation method based on a semi-conformal piezoelectric tunneling type micro-nano force-sensitive film is characterized by comprising the following steps:

1) selecting a silicon wafer, and etching a plurality of micro-nano structure patterns on the silicon wafer, wherein the steps comprise:

1.1) spin-coating photoresist on the surface of a silicon wafer and drying;

1.2) carrying out mask photoetching on the silicon wafer coated with the photoresist in a spinning mode by using an exposure machine;

1.3) placing the exposed silicon wafer into a developing solution for developing;

1.4) dry etching is carried out on the silicon chip to etch away SiO in the photoetching pattern₂；

1.5) sequentially carrying out wet etching and cleaning on the silicon wafer;

1.6) etching off the residual SiO in the silicon wafer₂Obtaining a micro-nano structured silicon sheet;

2) growing a micro-nano conformal graphene material layer on a silicon wafer by using a PECVD method; the micro-nano conformal graphene material layer comprises a graphene nano wall and a graphene film;

the method for growing the micro-nano conformal graphene material layer comprises the following steps:

3) carrying out micro-nano conformal graphene material layer transfer, wherein the steps comprise:

3.1) preparing a PDMS solution; pouring the PDMS solution on a micro-nano structured silicon wafer for growing a micro-nano conformal graphene material layer, and heating and curing;

3.2) cooling to room temperature, and stripping the PDMS and the micro-nano conformal graphene material layer from the silicon wafer mold;

4) preparing a piezoelectric polymer solution; the piezoelectric polymer solution comprises PVDF, PVDF: TrFE or PVDF-HFP;

spin-coating or spray-coating a piezoelectric polymer solution on the micro-nano conformal graphene material layer, and heating and drying to obtain a semi-conformal piezoelectric film;

5) and carrying out polarization treatment on the semi-conformal piezoelectric film in a high-voltage polarization device, so that the piezoelectric property of the semi-conformal piezoelectric film is improved.

Technical Field

The invention relates to the field of workpiece processing, in particular to a strip-type flexible linear array pressure sensor with a force-sensitive film, an intelligent tool fixture and a force-sensitive film preparation method.

Background

Compared with the traditional metal material cutting processing, the mechanical properties of the composite material such as hardness, rigidity and the like are lower. In the cutting process, the composite material is easy to generate large deformation, and the processing precision is influenced. Especially for the composite material special-shaped curved surface machining (as shown in fig. 1), the dimensional accuracy of the machined composite material workpiece usually cannot meet the design requirement.

Disclosure of Invention

The invention aims to provide a strip-type flexible linear array pressure sensor which comprises a flexible substrate and a plurality of pressure sensor linear array units.

The flexible substrate is constructed with a plurality of micro-nano structures. The pattern of the micro-nano structure comprises a pyramid, a column and a hemisphere.

The material of the flexible substrate comprises silicon rubber, polyurethane elastomer and Eco-Flex.

And a plurality of pressure sensor linear array units are integrated on the surface of the flexible substrate.

And stress conducting contacts are arranged on the surface of each linear array unit of the pressure sensor.

The area of the stress conduction contact is smaller than that of the linear array unit of the pressure sensor.

The stress-conducting contacts are made of an elastic material.

The pressure sensor linear array unit comprises interdigital electrodes and a semi-conformal micro-nano force-sensitive film, wherein the interdigital electrodes and the semi-conformal micro-nano force-sensitive film are integrated on the surface of a flexible substrate.

The semi-conformal micro-nano force-sensitive film comprises a micro-nano conformal conducting layer and a semi-conformal piezoelectric tunneling layer.

The micro-nano conformal conducting layer covers the surface of the micro-nano structure.

The semi-conformal piezoelectric tunneling layer partially covers the surface of the micro-nano conformal conductive layer.

The material of the micro-nano conformal conducting layer comprises graphene, a graphene nano wall, a carbon nano tube, carbon black, a conducting polymer and metal.

The material of the semi-conformal piezoelectric tunneling layer comprises PVDF, TrFE and PVDF-HFP.

The semi-conformal piezoelectric tunneling layer is subjected to high-voltage polarization treatment, and the piezoelectric property is improved.

The semi-conformal piezoelectric tunneling layer does not wrap the top of the micro-nano conformal conductive layer.

A preparation method based on a semi-conformal piezoelectric tunneling type micro-nano force-sensitive film comprises the following steps:

1) selecting a silicon wafer, and etching a plurality of micro-nano structure patterns on the silicon wafer, wherein the steps comprise:

1.1) spin-coating photoresist on the surface of a silicon wafer and drying;

1.2) carrying out mask photoetching on the silicon wafer coated with the photoresist in a spinning mode by using an exposure machine;

1.3) placing the exposed silicon wafer into a developing solution for developing;

1.4) dry etching is carried out on the silicon chip to etch away SiO in the photoetching pattern₂；

1.5) sequentially carrying out wet etching and cleaning on the silicon wafer;

1.6) etching off the residual SiO in the silicon wafer₂Obtaining a micro-nano structured silicon sheet;

2) growing a micro-nano conformal graphene material layer on a silicon wafer by using a PECVD method; the micro-nano conformal graphene material layer comprises a graphene nano wall and a graphene film;

the method for growing the micro-nano conformal graphene material layer comprises the following steps:

3) carrying out micro-nano conformal graphene material layer transfer, wherein the steps comprise:

3.1) preparing a PDMS solution; pouring the PDMS solution on a micro-nano structured silicon wafer for growing a micro-nano conformal graphene material layer, and heating and curing;

3.2) cooling to room temperature, and stripping the PDMS and the micro-nano conformal graphene material layer from the silicon wafer mold;

4) preparing a piezoelectric polymer solution; the piezoelectric polymer solution comprises PVDF, TrFE or PVDF-HFP;

spin-coating or spray-coating a piezoelectric polymer solution on the micro-nano conformal graphene material layer, and heating and drying to obtain a semi-conformal piezoelectric film;

5) and carrying out polarization treatment on the semi-conformal piezoelectric film in a high-voltage polarization device, so that the piezoelectric property of the semi-conformal piezoelectric film is improved.

An intelligent tool clamp with strip-type flexible linear array pressure sensors comprises a plurality of strip-type flexible linear array pressure sensors and a metal tool clamp.

The inner surface of the metal tool clamp is matched with the curved surface profile of the workpiece to be processed.

The metal tool clamp is used for fixing a workpiece to be machined.

The lower surface of the strip-type flexible linear array pressure sensor is attached to the inner surface of the metal tool clamp, and the upper surface of the strip-type flexible linear array pressure sensor is in contact with a workpiece to be processed.

The strip-type flexible linear array pressure sensor feeds the detected pressure back to an external processing equipment control system; the processing equipment control system is prestored with a pressure threshold value; and the processing equipment control system compares the received pressure with a pressure threshold value and adjusts the processing parameters in real time according to the comparison result.

And the strip-type flexible linear array pressure sensors are attached to the inner surface of the metal tool clamp one by one.

The strip-type flexible linear array pressure sensors are arranged on the inner surface of the metal tool clamp at equal intervals.

The invention has the advantages that the invention designs the intelligent tool clamp with the pressure sensing characteristic, and the metal-based tool clamp matched with the contour of the curved surface to be processed is processed based on the easy processing property of metal; and the strip-type flexible linear array pressure sensor is attached to the surface of the clamp by combining the light and ultrathin flexible pressure sensor. Due to the fact that the thickness of the flexible pressure sensor is thin, good conformal attachment can be conducted on the surface of the clamp.

This intelligence frock clamp can realize the real-time supervision of each position pressure distribution in the course of working, and especially the atress situation in machining region can feed back to operating personnel or digit control machine tool in real time to the power that the tool bit produced the work piece during adjustment, compensation are processed. The technical scheme can avoid the inconsistency of the curved surface thickness of the processed workpiece caused by uneven stress of each part.

The invention provides a flexible piezoresistive sensor constructed on the basis of a semi-conformal piezoelectric tunneling micro-nano force-sensitive film, which adopts a device structure of a lower interdigital electrode and an upper semi-conformal force-sensitive film. In order to improve the wide-range sensitivity and the corresponding time of the device, a PVDF piezoelectric material is used for constructing a semi-conformal piezoelectric tunneling layer, so that the initial current and the viscoelasticity relaxivity of the device are effectively reduced. In an initial state (no pressure loading), the semi-conformal piezoelectric layer can increase the initial contact resistance of the device; the polarization charge generated in the piezoelectric layer upon application of pressure can increase the pressure sensitive properties of the sensor.

Drawings

FIG. 1 is a profile of a composite material workpiece for machining a contoured surface;

FIG. 2 is a design drawing of a tooling fixture with pressure sensing features;

FIG. 3 is a design drawing I of a strip-type flexible linear array pressure sensor;

FIG. 4 is a design drawing II of the strip-type flexible linear array pressure sensor;

fig. 5 is a semi-conformal piezoelectric tunneling type micro-nano force-sensitive film.

FIG. 6 shows the design of a strip-type flexible linear array pressure sensor

FIG. 7 is a SEM representation diagram I of a semi-conformal piezoelectric tunneling type micro-nano force-sensitive film;

FIG. 8 is a SEM representation view II of a semi-conformal piezoelectric tunneling type micro-nano force-sensitive film;

FIG. 9 is a diagram of a force sensitive device structure;

FIG. 10 is a force sensitive property graph;

in the figure: the strip-type flexible linear array pressure sensor comprises a strip-type flexible linear array pressure sensor 1, a pressure sensor linear array unit 101, a stress conducting contact 102, a flexible substrate 2, a micro-nano conformal conducting layer 301, a semi-conformal piezoelectric tunneling layer 302, a metal tool clamp 4, a tool bit 5 and a curved surface outline 6 of a workpiece to be processed.

Detailed Description

The present invention is further illustrated by the following examples, but it should not be construed that the scope of the above-described subject matter is limited to the following examples. Various substitutions and alterations can be made without departing from the technical idea of the invention and the scope of the invention is covered by the present invention according to the common technical knowledge and the conventional means in the field.

Example 1:

referring to fig. 3 to 6, 9 and 10, a strip-type flexible linear array pressure sensor comprises a flexible substrate 2 and a plurality of pressure sensor linear array units 101;

the flexible substrate 2 is constructed with a plurality of micro-nano structures; the pattern of the micro-nano structure comprises a pyramid, a column and a hemisphere.

The material of the flexible substrate 2 comprises silicon rubber, polyurethane elastomer and Eco-Flex;

a plurality of pressure sensor linear array units 101 are integrated on the surface of the flexible substrate 2;

the surface of each pressure sensor linear array unit 101 is provided with a stress conduction contact 102;

the area of the stress-conducting contact 102 is smaller than the area of the pressure sensor linear array unit 101.

The stress conducting contacts 102 are made of an elastic material;

the pressure sensor linear array unit 101 comprises interdigital electrodes and a semi-conformal micro-nano force-sensitive film which are integrated on the surface of the flexible substrate 2;

the semi-conformal micro-nano force-sensitive film comprises a micro-nano conformal conducting layer 301 and a semi-conformal piezoelectric tunneling layer 302;

the micro-nano conformal conducting layer 301 covers the surface of the micro-nano structure;

the semi-conformal piezoelectric tunneling layer 302 partially covers the surface of the micro-nano conformal conductive layer 301.

The semi-conformal piezoelectric tunneling layer 302 is subjected to high-voltage polarization processing, and the piezoelectric property is improved.

The material of the micro-nano conformal conducting layer 301 comprises graphene, a graphene nanowall, a carbon nanotube, carbon black, a conducting polymer and metal;

the material of the semi-conformal piezoelectric tunneling layer 302 comprises PVDF, TrFE and PVDF-HFP.

The semi-conformal piezoelectric tunneling layer 302 does not wrap the top of the micro-nano conformal conductive layer 301.

Example 2:

a strip-type flexible linear array pressure sensor comprises a flexible substrate and a pressure sensor linear array unit, and a stress conduction contact is arranged above the sensing unit for improving the monitoring precision of cutting pressure. The stress conduction contacts correspond to the sensor units one by one, the contact materials are made of elastic materials such as silica gel, the size of the contact materials is controlled to be 0.5-0.8 times of that of the sensor units, and the thickness of the contact materials is 0.1-1.0 mm. The unit size, the number and the spacing of the linear array sensors are specifically designed according to the characteristics of the composite material workpiece to be processed. The strip width of the linear array sensor is 5-20 mm, and the overall thickness is less than or equal to 1.0 mm.

The flexible piezoresistive sensor is constructed on the basis of a semi-conformal piezoelectric tunneling type micro-nano force-sensitive film, and a device structure of a lower interdigital electrode and an upper semi-conformal force-sensitive film is adopted. In order to improve the wide-range sensitivity and the corresponding time of the device, a PVDF piezoelectric material is used for constructing a semi-conformal piezoelectric tunneling layer, so that the initial current and the viscoelasticity relaxivity of the device are effectively reduced. In an initial state (no pressure loading), the semi-conformal piezoelectric layer can increase the initial contact resistance of the device; the polarization charge generated in the piezoelectric layer upon application of pressure can increase the pressure sensitive properties of the sensor.

In order to improve the overall flexibility of the device, the thickness of the force-sensitive film prepared by the method is 0.1-1.0 mm; precisely processing a semi-conformal force-sensitive unit by adopting a laser circular cutting technology; and the preparation of the strip-type flexible linear array pressure sensor is realized by combining the flexible vacuum patch and film alignment laminating technology.

The pressure-sensitive film comprises a flexible elastic substrate, a micro-nano conformal conductive layer and a semi-conformal piezoelectric layer;

the flexible elastic substrate is one of silicon rubber, polyurethane elastomer and Eco-Flex, and a micro-nano structure is constructed by photoetching and soft photoetching; the micro-nano structure is characterized by being one of a pyramid, a column, a hemisphere and a random structure;

the conducting layer is one of graphene, a graphene nano wall, a carbon nano tube, carbon black, a conducting polymer and metal, and is wrapped on the surface of the flexible elastic micro-nano structure in a full-conformal mode, and the thickness of the conducting layer is 10 nanometers to 10 micrometers;

the piezoelectric layer is one of PVDF (polyvinylidene fluoride), PVDF, TrFE (copolymer of vinylidene fluoride and trifluoroethylene) and PVDF-HFP (poly (vinylidene fluoride-co-hexafluoropropylene)), the piezoelectric layer partially wraps the conductive layer microstructure, the top of the micro-nano structure is exposed, the area of an unwrapped area is 10% -40%, and the thickness of the piezoelectric layer is 10 nanometers-2 micrometers;

the preparation method of the conductive layer comprises chemical vapor deposition (CVD, PECVD), spin coating, spray coating, vacuum evaporation/sputtering. The method comprises the following steps of preparing a micro-nano conformal graphene or a graphene nanowall by adopting a CVD (chemical vapor deposition) or PECVD (plasma enhanced chemical vapor deposition) method, and transferring a flexible replica to a flexible elastic substrate; the micro-nano conformal conducting layers such as graphene, carbon nano tubes, carbon black and conducting polymers can be directly prepared on the micro-nano structured flexible elastic substrate by using a solution film deposition method such as spin coating or spray coating; metal films such as gold, silver, copper and the like can be directly deposited on the micro-nano structured flexible elastic substrate by using methods such as vacuum evaporation or sputtering;

the preparation method of the piezoelectric layer adopts a solution film deposition method such as spin coating or spray coating, and obtains a partially conformal piezoelectric film by controlling the film forming thickness and the annealing condition.

Example 3:

referring to fig. 7 and 8, a preparation method of a semi-conformal piezoelectric tunneling type micro-nano force-sensitive film comprises the following steps:

1) selecting a silicon wafer, and etching a plurality of micro-nano structure patterns on the silicon wafer, wherein the steps comprise:

1.1) spin-coating photoresist on the surface of a silicon wafer and drying;

1.2) carrying out mask photoetching on the silicon wafer coated with the photoresist in a spinning mode by using an exposure machine;

1.3) placing the exposed silicon wafer into a developing solution for developing;

1.4) dry etching is carried out on the silicon chip to etch away SiO in the photoetching pattern₂；

1.5) sequentially carrying out wet etching and cleaning on the silicon wafer;

1.6) etching off the residual SiO in the silicon wafer₂Obtaining a micro-nano structured silicon sheet;

2) growing a micro-nano conformal graphene material layer on a silicon wafer by using a PECVD method (a plasma enhanced chemical vapor deposition method); the micro-nano conformal graphene material layer comprises a graphene nano wall and a graphene film;

the method for growing the micro-nano conformal graphene material layer comprises the following steps:

3) carrying out micro-nano conformal graphene material layer transfer, wherein the steps comprise:

3.1) preparing a PDMS (polydimethylsiloxane) solution; pouring the PDMS solution on a micro-nano structured silicon wafer for growing a micro-nano conformal graphene material layer, and heating and curing;

3.2) cooling to room temperature, and stripping the PDMS and the micro-nano conformal graphene material layer from the silicon wafer mold;

4) preparing a piezoelectric polymer solution; the piezoelectric polymer solution comprises PVDF, TrFE or PVDF-HFP;

spin-coating or spray-coating a piezoelectric polymer solution on the micro-nano conformal graphene material layer, and heating and drying to obtain a semi-conformal piezoelectric film;

5) and carrying out polarization treatment on the semi-conformal piezoelectric film in a high-voltage polarization device, so that the piezoelectric property of the semi-conformal piezoelectric film is improved.

Example 4:

a preparation method based on a semi-conformal piezoelectric tunneling type micro-nano force-sensitive film comprises the following steps:

1) selecting a silicon wafer, and etching a plurality of micro-nano structure patterns on the silicon wafer, wherein the steps comprise:

1.1) spin-coating photoresist on the surface of the silicon wafer and drying.

1.2) carrying out mask photoetching on the silicon slice coated with the photoresist in a spinning mode by using an exposure machine.

1.3) placing the silicon wafer after exposure into a developing solution for development.

1.4) dry etching is carried out on the silicon chip to etch away SiO in the photoetching pattern₂。

1.5) carrying out wet etching and cleaning on the silicon wafer in sequence.

1.6) etching off the residual SiO in the silicon wafer₂。

2) Growing a graphene nanowall or a graphene film on a silicon wafer by using a PECVD method, comprising the following steps:

3) carrying out micro-nano conformal graphene material layer transfer, wherein the steps comprise:

3.1) preparing a PDMS solution; pouring the PDMS solution on a micro-nano structured silicon wafer for growing a micro-nano conformal graphene material layer, and heating and curing;

3.2) cooling to room temperature, and stripping the PDMS and the micro-nano conformal graphene material layer from the silicon wafer mold;

4) preparing a piezoelectric polymer (PVDF or PVDF: TrFE or PVDF-HFP) solution; and spin-coating or spraying a PVDF (or PVDF: TrFE or PVDF-HFP) solution on the graphene nanowall or the graphene nanofilm, and heating and drying.

And optimizing the concentration of the piezoelectric polymer solution, spin coating or spray coating parameters and annealing parameters to obtain the semi-conformal piezoelectric film.

And carrying out polarization treatment on the semi-conformal piezoelectric film in a high-voltage polarization device so as to improve the piezoelectric property of the semi-conformal piezoelectric film.

Example 5:

the preparation method of the semi-conformal piezoelectric tunneling type micro-nano force sensitive film based on the graphene nanowall with the micro-nano structure of a pyramid and the conducting layer of PECVD conformal growth comprises the following steps:

1) pyramid etching template

1.1) silicon wafer acquisition. Taking a silicon wafer with an oxidation layer of 300nm, sequentially cleaning the silicon wafer with deionized water, acetone and ethanol to ensure that the clean surface of the silicon wafer has no impurities, and placing the cleaned silicon wafer in the ethanol for the last time for storage for later use;

1.2) spin coating photoresist. Blow-drying a clean silicon wafer by a nitrogen gun, fixing the silicon wafer on a spin coater in vacuum, spin-coating a photoresist on Si according to a certain thickness, and heating and drying the spin-coated silicon wafer on a hot plate;

1.3) exposure. Carrying out mask photoetching on the silicon wafer with the photoresist rotated by an exposure machine

1.4) developing. And placing the exposed silicon wafer into a developing solution for developing.

1.5) dry etching. Placing the silicon wafer obtained in the step 4 into RIE (reactive ion etching) for etchingEtching SiO in the pattern in the etching machine₂；

1.6) wet etching. Cleaning the photoresist on the surface of the silicon wafer obtained by dry etching with acetone and ethanol, and drying; preparing wet etching solution KOH H₂0, 2.89g of IPA (isopropyl alcohol), 50ml of 15ml of the wet etching solution, putting the wet etching solution into a water bath kettle, keeping the temperature constant at 80 ℃, then putting the silicon wafer into the etching solution, heating the silicon wafer in the water bath for 30min, and immediately taking out the silicon wafer and washing the silicon wafer with deionized water;

1.7) residual SiO₂And (5) etching. SiO possibly remained around the microstructure in the silicon wafer finished by wet etching₂Etching the silicon wafer in HF atmosphere for about 1min to remove SiO₂And then cleaning the silicon wafer by using deionized water, acetone and ethanol in sequence.

2) Growing graphene nanowall

And growing the graphene nanowalls on the silicon wafer by using a PECVD method.

2.1) air-firing. Firstly, the tubular furnace is subjected to empty burning at 800 ℃ for 30min to remove impurities in the tubular furnace, and then the temperature is reduced

2.2) growing. Placing the silicon chip in a heating area of a tube furnace, vacuumizing, and then adjusting H₂The flow index is 10, the temperature is raised to 700 ℃ for 30min, the temperature is kept for 30min, the temperature is raised to 750 ℃ for 10min, the radio frequency is started, the frequency is adjusted to 250, the Pr is adjusted to 0, and the CH is adjusted₄：H₂6: 4, growing for 60min, turning off the radio frequency after the growth is finished, and adjusting the gas to be H₂Index 10, CH₄0, opening the cover and cooling, taking out the sample when the temperature is reduced to normal temperature

2.3) exhausting and finishing. Close CH₄Cylinder valve, will CH₄Adjust to the cleaning gear to wait for CH₄The numerical value is decreased to more than ten, and the CH is loosened₄And (4) closing a secondary valve, and closing the vacuum pump and the tube furnace.

3) Graphene nanowall transfer

Placing the silicon wafer with the grown graphene nanometer wall on PET (polyethylene terephthalate), fixing the PET on an iron plate, and preparing PDMS: crosslinking agent 10: 1, stirring, vacuumizing and defoaming, pouring the PDMS solution on a silicon chip to naturally level the PDMS solution, and heating and curing the PDMS solution at 80 ℃ for 1h

4) Spin-coated PVDF

Preparing a PVDF solution, wherein the PVDF solution is dissolved by stirring at the temperature of 65 ℃ and the rmp of 950 under the condition that the NMP is 1: 10; treating the graphene nanowall/PDMS in an oxygen plasma cleaning machine at low power for 10s, then spin-coating PVDF (with the rotation speed of 500-3000 rpm) on the graphene nanowall by using a spin coater, and heating and drying at 40 ℃ for 1h, 60 ℃ for 1h and 80 ℃ for 1 h.

Example 6:

referring to fig. 2, an intelligent tool clamp with strip-type flexible linear array pressure sensors comprises a plurality of strip-type flexible linear array pressure sensors 1 and a metal tool clamp 4;

the inner surface of the metal tool clamp 4 is matched with the curved surface profile of the workpiece to be processed;

the metal tool clamp 4 is used for fixing a workpiece to be machined;

the lower surface of the strip-type flexible linear array pressure sensor 1 is attached to the inner surface of the metal tool clamp 4, and the upper surface of the strip-type flexible linear array pressure sensor is in contact with a workpiece to be processed;

during the machining process of the tool bit 5 on the workpiece to be machined, the strip-type flexible linear array pressure sensor 1 monitors the pressure applied by the workpiece to be machined.

The strip-type flexible linear array pressure sensors 1 are attached to the inner surface of the metal tool clamp 4 one by one.

The strip-type flexible linear array pressure sensors 1 are arranged on the inner surface of the metal tool clamp 4 at equal intervals.

The strip-type flexible linear array pressure sensor feeds the detected pressure back to an external processing equipment control system; the processing equipment control system is prestored with a pressure threshold value; and the processing equipment control system compares the received pressure with a pressure threshold value and adjusts the processing parameters in real time according to the comparison result.

Example 7:

an intelligent tool clamp with a strip-type flexible linear array pressure sensor comprises a clamp and the strip-type flexible linear array pressure sensor attached to the surface of the clamp. Due to the fact that the thickness of the flexible pressure sensor is thin, good conformal attachment can be conducted on the surface of the clamp.

This intelligence frock clamp can realize the real-time supervision of each position pressure distribution in the course of working, and especially the atress situation in machining region can feed back to operating personnel or digit control machine tool in real time to the power that the tool bit produced the work piece during adjustment, compensation are processed. The technical scheme can avoid the inconsistency of the curved surface thickness of the processed workpiece caused by uneven stress of each part.

Specifically, the flexible linear array pressure sensor comprises a flexible substrate and a pressure sensor linear array unit, and a stress conduction contact is arranged above the sensing unit for improving the monitoring precision of cutting pressure. The stress conduction contacts correspond to the sensor units one by one, the contact materials are made of elastic materials such as silica gel, the size of the contact materials is controlled to be 0.5-0.8 times of that of the sensor units, and the thickness of the contact materials is 0.1-1.0 mm. The unit size, the number and the spacing of the linear array sensors are specifically designed according to the characteristics of the composite material workpiece to be processed. The strip width of the linear array sensor is 5-20 mm, and the overall thickness is less than or equal to 1.0 mm.

Due to the fact that the strip-type strip-by-strip attaching mode is adopted, the complex surface of the tool clamp can be effectively covered by the sensor. And on the premise of ensuring that the key points are detected, the distances of the strip sensors are distributed at equal intervals or at unequal intervals according to the characteristics of the curved surface profile 6 of the workpiece to be processed. In addition, the processing circuit of the distributed sensor can select two schemes of serial connection or parallel connection of the linear arrays.

In the processing process of a workpiece to be processed, the strip-type flexible linear array pressure sensor 1 detects the pressure applied to each part of the surface of the workpiece to be processed in real time.

The strip-type flexible linear array pressure sensor feeds back the detected surface pressure of the workpiece to a processing equipment control system, and the control system judges whether the applied processing pressure is larger or smaller, so that the processing parameters are adjusted in real time.

Example 8:

a strip-type flexible linear array pressure sensor comprises a flexible substrate 2 and a plurality of pressure sensor linear array units 101;

the flexible substrate 2 is constructed with a plurality of micro-nano structures; the pattern of the micro-nano structure comprises a pyramid, a column and a hemisphere.

The material of the flexible substrate 2 comprises silicon rubber, polyurethane elastomer and Eco-Flex;

a plurality of pressure sensor linear array units 101 are integrated on the surface of the flexible substrate 2;

the surface of each pressure sensor linear array unit 101 is provided with a stress conduction contact 102;

the area of the stress-conducting contact 102 is smaller than the area of the pressure sensor linear array unit 101.

The stress conducting contacts 102 are made of an elastic material;

the pressure sensor linear array unit 101 comprises interdigital electrodes and a semi-conformal micro-nano force-sensitive film which are integrated on the surface of the flexible substrate 2;

the semi-conformal micro-nano force-sensitive film comprises a micro-nano conformal conducting layer 301 and a semi-conformal piezoelectric tunneling layer 302;

the micro-nano conformal conducting layer 301 covers the surface of the micro-nano structure;

the semi-conformal piezoelectric tunneling layer 302 partially covers the surface of the micro-nano conformal conductive layer 301.

The material of the micro-nano conformal conducting layer 301 comprises graphene, a graphene nanowall, a carbon nanotube, carbon black, a conducting polymer and metal;

the material of the semi-conformal piezoelectric tunneling layer 302 comprises PVDF, TrFE and PVDF-HFP.

The semi-conformal piezoelectric tunneling layer 302 does not wrap the top of the micro-nano conformal conductive layer 301.

A preparation method based on a semi-conformal piezoelectric tunneling type micro-nano force-sensitive film comprises the following steps:

1) selecting a silicon wafer, and etching a plurality of micro-nano structure patterns on the silicon wafer, wherein the steps comprise:

1.1) spin-coating photoresist on the surface of a silicon wafer and drying;

1.2) carrying out mask photoetching on the silicon wafer coated with the photoresist in a spinning mode by using an exposure machine;

1.3) placing the exposed silicon wafer into a developing solution for developing;

1.4) dry etching of silicon wafersEtching away SiO in the pattern₂；

1.5) sequentially carrying out wet etching and cleaning on the silicon wafer;

1.6) etching off the residual SiO in the silicon wafer₂；

2) The method for growing the graphene nanowalls on the silicon wafer by using the PECVD method comprises the following steps:

3) carrying out graphene nanowall transfer, comprising the following steps:

3.1) placing the silicon wafer with the graphene nanowalls on PET, and fixing the PET;

3.2) preparing a PDMS solution; pouring the PDMS solution on a silicon chip, and heating and curing;

4) preparing a PVDF solution; and (3) spin-coating the PVDF solution on the graphene nanometer wall, and heating and drying.

An intelligent tool clamp with strip-type flexible linear array pressure sensors comprises a plurality of strip-type flexible linear array pressure sensors and a metal tool clamp;

the inner surface of the metal tool clamp is matched with the curved surface profile of the workpiece to be processed;

the metal tool clamp is used for fixing a workpiece to be machined;

the lower surface of the strip-type flexible linear array pressure sensor is attached to the inner surface of the metal tool clamp, and the upper surface of the strip-type flexible linear array pressure sensor is in contact with a workpiece to be processed;

in the processing process of the workpiece to be processed, the strip-type flexible linear array pressure sensor monitors the pressure applied by the workpiece to be processed.

And the strip-type flexible linear array pressure sensors are attached to the inner surface of the metal tool clamp one by one.

The strip-type flexible linear array pressure sensors are arranged on the inner surface of the metal tool clamp at equal intervals.

Example 9:

the processing method of the intelligent tool clamp with the strip-type flexible linear array pressure sensor comprises the following steps:

1) determining a workpiece to be processed; the workpiece to be processed has the characteristic of a special-shaped curved surface.

2) Attaching a flexible sensor on the surface of the tool clamp; the flexible sensor is provided with a plurality of sensing units; a sensing unit corresponds to a sub-area of the workpiece to be processed;

the inner surface of the tool clamp is completely matched with the standard workpiece.

3) Placing a workpiece to be processed on a tool clamp, and enabling the inner surface of the workpiece to be processed to be attached to the flexible sensor; a pre-processing error gap exists between the inner surface of the workpiece to be processed and the flexible sensor;

4) the workpiece to be processed and the tool clamp are connected through the fixing hole bolt, the fastening connection of the workpiece to be processed and the tool clamp is completed, and the inner surface of the workpiece to be processed exerts pressure on the flexible sensor; the sensing unit generates deformation after being stressed, so that an electric signal is output to an upper computer;

5) the upper computer judges whether the surface of the workpiece to be machined is different from the inner surface of the tool clamp in shape or not on the basis of the received electric signals, if not, the part machining is finished, and if yes, the step 6 is carried out);

the method for judging whether the surface of the workpiece to be machined is different from the inner surface of the tool clamp in shape comprises the following steps: judging whether the electric signals output by each sensing unit are equal, if so, judging that the shape difference does not exist between the workpiece to be processed and the inner surface of the tool clamp, and if not, judging that the shape difference exists;

when the shape difference exists between the machined part and the inner surface of the tool clamp, recording the number of repeated electric signal values, and taking the electric signal with the largest number of repeated electric signals as a reference electric signal; and the sensing unit with the electric signal not equal to the reference electric signal is a to-be-processed sensing unit.

6) Determining sub-regions of the workpiece to be processed with shape difference, and recording as the sub-regions to be processed;

determining the difference degree between the sub-area to be processed and the inner surface of the tool clamp; the degree of difference includes a difference shape and a difference thickness;

the sub-area of the workpiece to be processed with the shape difference is an area corresponding to the sensing unit to be processed.

7) The upper computer controls the processing cutter to process the subarea to be processed according to the difference degree; after the processing is finished, returning to the step 5); in the machining process and after machining is completed, the sensing unit continuously generates an electric signal under the pressure action of a workpiece to be machined and sends the electric signal to an upper computer.

The flexible sensor also monitors the real-time pressure of the tool bit action position of the machining tool and feeds the real-time pressure back to the upper computer, so that the upper computer adjusts and compensates the force of the tool bit on the workpiece to be machined during machining.