Polymer molding detection device based on piezoelectric-thermocouple array and optical integration

Abstract

The present invention discloses a polymer molding detection device based on piezoelectric-thermocouple array and optical integration, wherein the basic components include: a measurement channel, an outer edge layer, and an insulating sleeve arranged coaxially from the inside to the outside; the measurement channel is a microarray structure channel, in which the polymer melt flows axially; the temperature control component includes a heating coil and a cooling water channel, the heating coil is arranged on the outside of the outer edge layer, and the cooling water channel is arranged in the outer edge layer; the microarray component includes two thermocouple sensor arrays and two piezoelectric sensor arrays of equal thickness; the two thermocouple sensor arrays are arranged relatively on the surface of the inner wall of the measurement channel, the piezoelectric sensor array and the thermocouple sensor array are arranged in a stacked manner, and the positions of the two piezoelectric sensor arrays are relative; the optical axis of the optical-stress measurement component is perpendicular to the axis of the measurement channel, and the internal stress of the polymer melt is detected by polarized light and a CCD camera. The present invention can realize the detection of global polymer melt information in the micro-molding measurement channel.

Description

Technical Field

[0001] The invention relates to the field of polymer molding processing detection, and in particular to a polymer molding detection device based on a piezoelectric-thermocouple array and optical integration. Background Art

[0002] Polymer micro-molding technology is one of the main directions for the development of the country's future strategic emerging industries. With its unique manufacturing advantages of high integration, high efficiency, low carbon, low cost, and resource conservation, it is widely used in consumer electronics, information and communications, computers, automobiles, energy, medical care, national defense and other fields.

[0003] Polymer micro-molding manufacturing technologies mainly include: micro-injection molding, micro-extrusion, micro-foaming, micro-nano 3D printing, etc. Micro-injection molding is used for mass production of products with overall dimensions, characteristic functional areas or tolerance requirements in millimeters or even microns, such as precision optical lenses, car lamp parts, etc. Micro-extrusion generally uses a die with a specific shape, supplemented by stretching to continuously mold products with micron-level characteristic dimensions, such as the preparation of various medical micro-tubes. Micro-foaming is made by special process control or adding foaming agents to form porous polymer products with pores ranging from tens to hundreds of microns. The precision of micro-nano 3D printing can theoretically reach the mesoscopic, microscopic or nanoscopic level, which is used for personalized replication of tiny structures, but its printing speed and production capacity are currently limited. Compared with various laboratory prototype micro-molding methods, the above-mentioned polymer micro-structure manufacturing technology can not only realize the mass production of lightweight, high-precision, high-performance micro-structure products, but also saves raw materials and is more economical and energy-saving. The changes in polymer melt temperature and pressure run through the process of all the above-mentioned micro-molding technologies and are the key parameters for regulating the continuous consistency of the quality of micro-structure products. At the same time, the internal stress generated by flow or cooling in polymer micro-molding greatly affects the quality of the product, and its online detection is very important.

[0004] At present, the field of polymer microstructure manufacturing detection is relatively weak, and there are still great difficulties in detecting the information of polymer melt flow in the micro-molding process. Conventional sensors have disadvantages such as large probe diameter, invasiveness, and delay, and cannot meet the needs of accurately detecting global polymer melt information under the influence of factors such as raw material property fluctuations, equipment performance and external environment changes, and auxiliary molding processes in the polymer micro-molding process. In summary, the existing technology still cannot be directly applied to the actual production process, and there are still many difficulties in realizing the detection of the melt state in micro-molding. Summary of the invention

[0005] In view of the deficiencies of the prior art, the present invention proposes a polymer molding detection device based on a piezoelectric-thermocouple array and optical integration.

[0006] The specific technical solutions are as follows:

[0007] A polymer molding detection device based on piezoelectric-thermocouple array and optical integration, comprising: a microarray component, a temperature control component, an optical-stress measurement component, and a basic component;

[0008] The basic components include: a coaxially arranged thermal insulation sleeve, an outer edge layer, and a measuring channel; the measuring channel is a microarray structure channel, and during the micro-molding process, the polymer melt flows axially in the measuring channel; the outer edge layer is arranged on the outside of the measuring channel, and the thermal insulation sleeve is arranged on the outside of the outer edge layer;

[0009] The temperature control assembly includes a heating coil and a cooling water channel. The heating coil is arranged outside the outer edge layer and is covered with an insulating sleeve to uniformly heat the polymer melt in the measuring channel. The cooling water channel is arranged in the outer edge layer to uniformly cool the polymer melt in the measuring channel.

[0010] The microarray assembly includes two thermocouple sensor arrays and two piezoelectric sensor arrays; the two thermocouple sensor arrays are arranged oppositely on the surface of the inner wall of the measuring channel, and are used to detect the temperature of the polymer melt in the measuring channel; the piezoelectric sensor array and the thermocouple sensor array are arranged in a stacked manner, and the thermocouple sensor array is located between the piezoelectric sensor array and the inner wall of the measuring channel, and the two piezoelectric sensor arrays have the same thickness and are located oppositely, and are used to detect the pressure of the polymer melt in the measuring channel;

[0011] The optical axis of the optical-stress measurement component is arranged perpendicularly to the axis of the measurement channel, and the internal stress of the polymer melt is detected by polarized light and a CCD camera by means of an optical path design based on the stress birefringence principle.

[0012] Furthermore, the optical-stress measurement component includes: a light source, a monochromator, a collimator, a polarizer, a quartz optical window, an analysis mirror, and a CCD camera arranged in sequence on the same optical axis; there are two quartz optical windows, which are respectively opened on opposite side walls of the measurement channel; the light emitted by the light source is converted into monochromatic light by the monochromator, and the monochromatic light is converted into polarized light by the collimator and the polarizer in sequence, and is emitted into the polymer melt in the measurement channel through a quartz optical window, and then emitted from another quartz optical window; since polarized light undergoes birefringence in an inhomogeneous polymer melt, the light after birefringence interferes and superimposes, and after passing through the analysis mirror, a birefringent stripe pattern is presented in the CCD camera.

[0013] Furthermore, the heating coil is evenly arranged on the outside of the outer edge layer along the axial direction, and the cooling water path is evenly wound along the axial direction of the measuring channel.

[0014] Furthermore, the cooling water channel is parallel to the axis of the measuring channel and is evenly arranged along the circumference thereof.

[0015] Furthermore, the cross-sectional shape of the measuring channel is circular, rectangular, triangular or trapezoidal.

[0016] A polymer molding detection method based on a piezoelectric-thermocouple array and optical integration is implemented based on the polymer molding detection device based on a piezoelectric-thermocouple array and optical integration, specifically:

[0017] During the micro-molding process, the polymer melt flows axially inside the measuring channel. At this time, the piezoelectric sensor array detects the pressure of the polymer melt based on the relationship between pressure and potential. The expression based on the relationship between pressure and potential is as follows:

[0018]

[0019] Where P is the pressure of the polymer melt, V p is the potential difference between the two piezoelectric sensor arrays, c p is the pressure conversion coefficient, H is the thickness of the piezoelectric sensor array;

[0020] The thermocouple sensor array uses the thermoelectric effect to detect the temperature of the polymer melt. The relationship between temperature and potential is expressed as follows:

[0021] T=c t V t

[0022] Where T is the temperature of the polymer melt, c t is the temperature conversion coefficient, V t is the potential difference between the two thermocouple sensor arrays;

[0023] The optical-stress measurement assembly detects the internal stress of the polymer melt, and the relationship between the number of optical fringes in the optical CCD camera and the internal stress is expressed as follows:

[0024]

[0025] Where N is the number of optical fringes, C is the photoelastic coefficient, λ is the wavelength of the incident light; σ1 is the first principal stress, i.e., the stress in the flow direction of the polymer melt; σ2 is the second principal stress, i.e., the stress perpendicular to the flow direction of the polymer melt; and t is the channel thickness of the measurement channel.

[0026] The beneficial effects of the present invention are:

[0027] (1) The present invention develops a set of high-precision polymer melt information measurement devices that are easy to integrate through the combined design of stacked arrays and optical integration. The device overcomes the shortcomings of conventional sensors such as large probe diameter, invasiveness, and delay, and can collect the polymer melt state information in the entire micro-molding measurement channel.

[0028] (2) The device of the present invention integrates optical-stress measurement components, which can be used to study the nonlinear rheological behavior of micro-molded polymer melts and the critical conditions and laws of specific rheological phenomena such as wall slip, shear heating and unstable flow, and to establish measurement and characterization methods for the viscosity and elasticity of polymer melts. It plays an important role in promoting the development of micro-molding detection disciplines and opening up new fields of precision intelligent manufacturing of polymer microstructures. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of a polymer molding detection device based on a piezoelectric-thermocouple array and optical integration according to the present invention.

[0030] Figure 2 It is a schematic diagram of the design of the special-shaped measurement channel and stacked grid microarray of the present invention.

[0031] Figure 3 It is a schematic diagram of the structure of the optical-stress measurement assembly of the present invention.

[0032] Figure 4 It is a schematic diagram of the birefringent optical fringe pattern presented on the CCD camera of the present invention.

[0033] Figure 5 It is a schematic flow chart of the polymer molding detection method based on piezoelectric-thermocouple array and optical integration of the present invention.

[0034] Figure 6 It is a schematic diagram of the detection principle of the piezoelectric sensor array of the present invention.

[0035] Figure 7 It is a schematic diagram of the detection principle of the thermocouple sensor array of the present invention.

[0036] In the figure, microarray component 1, temperature control component 2, optical-stress measurement component 3, basic component 4, upper thermocouple sensor array 101, upper piezoelectric sensor array 102, lower piezoelectric sensor array 103, lower thermocouple sensor array 104, heating coil 201, cooling water channel 202, light source 301, monochromator 302, collimator 303, polarizer 304, quartz optical window 305, analysis mirror 306, CCD camera 307, insulation sleeve 401, outer edge layer 402, and measurement channel 403. DETAILED DESCRIPTION

[0037] The present invention will be described in detail below according to the accompanying drawings and preferred embodiments, and the purpose and effect of the present invention will become more clear. The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0038] like Figure 1As shown, a polymer molding detection device based on a piezoelectric-thermocouple array and optical integration includes: a microarray component 1, a temperature control component 2, an optical-stress measurement component 3, and a basic component 4.

[0039] The basic component 4 includes: an insulating sleeve 401, an outer edge layer 402, and a measuring channel 403. The measuring channel 403 is a microarray structure channel, and the polymer melt flows in the measuring channel 403 during the micromolding process. The insulating sleeve 401, the outer edge layer 402, and the measuring channel 403 are coaxially arranged in sequence, wherein the outer edge layer 402 is evenly arranged on the outside of the measuring channel 403 in the circumferential direction to play a fixing role; the insulating sleeve 401 is evenly arranged on the outside of the outer edge layer 402 in the circumferential direction to play a role in isolating the influence of the external environment.

[0040] The temperature control component 2 includes a heating coil 201 and a cooling water path 202, and the cooling water path 202 and the heating coil 201 are both arranged circumferentially on the outside of the measuring channel 403. The heating coil 201 is evenly arranged on the outside of the outer edge layer 402 along the axial direction, and is covered with an insulating sleeve 401 on the outside, so as to evenly heat the polymer melt flowing inside the measuring channel 403. The cooling water path 202 is evenly arranged in the outer edge layer 402, and can be evenly wound along the axial direction of the measuring channel 403, or can be evenly arranged parallel to the axis of the measuring channel 403 and along its circumference, so as to evenly cool the polymer melt flowing inside the measuring channel 403. The temperature control component 2 is used to constantly adjust the temperature in the measuring channel 403 and make the temperature uniform.

[0041] The microarray assembly 1 includes: an upper thermocouple sensor array 101, an upper piezoelectric sensor array 102, a lower piezoelectric sensor array 103, and a lower thermocouple sensor array 104. The upper thermocouple sensor array 101 is arranged on the upper surface of the inner wall of the measuring channel 403, and the lower thermocouple sensor array 104 is arranged on the lower surface of the inner wall of the measuring channel 403. The two thermocouple sensor arrays have the same specifications and are located opposite to each other. The upper thermocouple sensor array 101 and the lower thermocouple sensor array 104 are both used to detect the temperature of the polymer melt flowing inside the measuring channel 403. The upper piezoelectric sensor array 102 and the upper thermocouple sensor array 101 are arranged in a stacked manner, and the upper thermocouple sensor array 101 is located between the upper piezoelectric sensor array 102 and the inner wall of the measuring channel 403; the lower piezoelectric sensor array 103 and the lower thermocouple sensor array 104 are arranged in a stacked manner, and the lower thermocouple sensor array 104 is located between the lower piezoelectric sensor array 103 and the inner wall of the measuring channel 403; the two piezoelectric sensor arrays have the same specifications (specifically the same thickness) and are located relative to each other, and the upper piezoelectric sensor array 102 and the lower piezoelectric sensor array 103 are both used to detect the pressure of the polymer melt flowing inside the measuring channel 403. Compared with the detection of conventional sensors using probes, the stacked sensor design overcomes its shortcomings such as large diameter, intrusion, and delay, and meets the needs of accurately detecting global polymer melt information under the influence of factors such as fluctuations in raw material properties, changes in equipment performance and external environment, and auxiliary molding processes in the polymer micro-molding process.

[0042] like Figure 2 As shown, the arrangement of the microarray component 1 is not limited to the cross-sectional shape of the measuring channel 3. For various types of irregular microchannels with cross-sectional shapes such as circle, rectangle, triangle, trapezoid, etc., the microarray component 1 used in the present invention can be applicable only by performing corresponding grid microarray design, and then the state of the polymer melt flowing inside the measuring channel 403 can be detected.

[0043] like Figure 3As shown, the optical-stress measurement assembly 3 includes: a light source 301, a monochromator 302, a collimator 303, a polarizer 304, a quartz optical window 305, an analysis mirror 306, and a CCD camera 307 arranged in sequence on the same optical axis. The optical axis of the optical-stress measurement assembly 3 is perpendicular to the axis of the measurement channel 403. With the help of the optical path design based on the stress birefringence principle, the internal stress of the polymer melt is detected by polarized light and a CCD camera. The light emitted by the light source 301 is converted into monochromatic light by the monochromator 302, and the monochromatic light is converted into polarized light by the collimator 303 and the polarizer 304 in turn. There are two quartz optical windows 305, which are respectively opened on the opposite side walls of the measuring channel 403. The polarized light is transmitted from one quartz optical window 305 into the polymer melt flowing inside the measuring channel 403, and then emitted from the other quartz optical window 305. Since the polarized light is birefred in the inhomogeneous polymer melt in the measuring channel 403, the light after birefringence is interfered and superimposed, and after passing through the analysis mirror 306, it is displayed in the CCD camera 307 as follows: Figure 4 The birefringent optical fringes shown in the figure reflect the stress field distribution inside the polymer melt in the measurement channel 403. The design of the present invention breaks through the limitation that the traditional offline method can only detect the condensed polymer solid, and realizes the online monitoring of the internal stress of the melt flow process in the polymer molding process.

[0044] like Figure 5 As shown, based on the above-mentioned polymer molding detection device based on piezoelectric-thermocouple array and optical integration, a polymer molding detection method based on piezoelectric-thermocouple array and optical integration is proposed, specifically:

[0045] During the micro-molding process, the polymer melt flows axially inside the measuring channel 403. At this time, the upper piezoelectric sensor array 102 and the lower piezoelectric sensor array 103 detect the pressure of the polymer melt according to the relationship between pressure and potential. The detection principle is as follows: Figure 6 As shown, the relationship between pressure and electric potential is expressed as follows:

[0046]

[0047] Where P is the pressure of the polymer melt, V p is the potential difference between the two piezoelectric sensor arrays, c p is the pressure conversion coefficient, and H is the thickness of the piezoelectric sensor array.

[0048] The upper thermocouple sensor array 101 and the lower thermocouple sensor array 104 use the thermoelectric effect to detect the temperature of the polymer melt. The detection principle is as follows: Figure 7 As shown, the relationship between temperature and electric potential is expressed as follows:

[0049] T=c t V t

[0050] Where T is the temperature of the polymer melt, c t is the temperature conversion coefficient, V t is the potential difference between the two thermocouple sensor arrays.

[0051] The optical-stress measurement component 3 detects the internal stress level of the polymer melt. The relationship between the number of optical fringes in the optical CCD camera 307 and the internal stress is expressed as follows:

[0052]

[0053] Wherein, N is the number of optical fringes, C is the photoelastic coefficient, λ is the wavelength of the incident light; σ1 is the first principal stress, specifically the stress in the flow direction of the polymer melt; σ2 is the second principal stress, specifically the stress perpendicular to the flow direction of the polymer melt (i.e., the stress in the optical axis direction of the optical-stress measurement component 3); t is the channel thickness of the measurement channel 403.

[0054] The present invention develops a set of high-precision polymer melt information measurement devices that are easy to integrate through stacked array and optical integrated design. The device can study the nonlinear rheological behavior of micro-molded polymer melts and the critical conditions and laws of specific rheological phenomena such as wall slip, shear heating and unstable flow, and establish measurement and characterization methods for polymer melt viscosity and elasticity. It plays an important role in promoting the development of micro-molding detection disciplines and opening up new fields of precise intelligent manufacturing of polymer microstructures.

[0055] Those skilled in the art can understand that the above are only preferred examples of the invention and are not intended to limit the invention. Although the invention is described in detail with reference to the above examples, those skilled in the art can still modify the technical solutions recorded in the above examples or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, etc. made within the spirit and principle of the invention shall be included in the protection scope of the invention.

Claims

1. A polymer molding detection device based on piezoelectric-thermocouple array and optical integration, characterized in that: include: Microarray assembly, temperature control assembly, optical-stress measurement assembly, basic assembly; The basic components include: a coaxially arranged thermal insulation sleeve, an outer edge layer, and a measuring channel; the measuring channel is a microarray structure channel, and during the micro-molding process, the polymer melt flows axially in the measuring channel; the outer edge layer is arranged on the outside of the measuring channel, and the thermal insulation sleeve is arranged on the outside of the outer edge layer; The temperature control assembly includes a heating coil and a cooling water channel. The heating coil is arranged outside the outer edge layer and is covered with an insulating sleeve to uniformly heat the polymer melt in the measuring channel. The cooling water channel is arranged in the outer edge layer to uniformly cool the polymer melt in the measuring channel. The microarray assembly includes two thermocouple sensor arrays and two piezoelectric sensor arrays; the two thermocouple sensor arrays are arranged oppositely on the surface of the inner wall of the measuring channel, and are used to detect the temperature of the polymer melt in the measuring channel; the piezoelectric sensor array and the thermocouple sensor array are arranged in a stacked manner, and the thermocouple sensor array is located between the piezoelectric sensor array and the inner wall of the measuring channel, and the two piezoelectric sensor arrays have the same thickness and are located oppositely, and are used to detect the pressure of the polymer melt in the measuring channel; The optical axis of the optical-stress measurement component is arranged perpendicularly to the axis of the measurement channel. The optical-stress measurement component includes two quartz optical windows, which are respectively opened on opposite side walls of the measurement channel. Polarized light is emitted into the polymer melt in the measurement channel through one quartz optical window and then emitted from the other quartz optical window. With the help of the optical path design based on the principle of stress birefringence, the internal stress of the polymer melt is detected by polarized light and a CCD camera.

2. The polymer molding detection device based on piezoelectric-thermocouple array and optical integration according to claim 1 is characterized in that: The optical-stress measurement component includes: a light source, a monochromator, a collimator, a polarizer, a quartz optical window, an analysis mirror, and a CCD camera arranged in sequence on the same optical axis; the light emitted by the light source is converted into monochromatic light by the monochromator, and the monochromatic light is converted into polarized light by the collimator and the polarizer in sequence, and is emitted into the polymer melt in the measurement channel through a quartz optical window, and then emitted from another quartz optical window; since polarized light undergoes birefringence in an inhomogeneous polymer melt, the light after birefringence interferes and superimposes, and after passing through the analysis mirror, a birefringent fringe pattern is presented in the CCD camera.

3. The polymer molding detection device based on piezoelectric-thermocouple array and optical integration according to claim 1, characterized in that: The heating coil is evenly arranged on the outside of the outer edge layer along the axial direction, and the cooling water path is evenly wound along the axial direction of the measuring channel.

4. The polymer molding detection device based on piezoelectric-thermocouple array and optical integration according to claim 1, characterized in that: The cooling water channel is parallel to the axis of the measuring channel and is evenly arranged along the circumference thereof.

5. The polymer molding detection device based on piezoelectric-thermocouple array and optical integration according to claim 1, characterized in that: The cross-sectional shape of the measuring channel is circular, rectangular, triangular or trapezoidal.

6. A polymer molding detection method based on piezoelectric-thermocouple array and optical integration, which is implemented based on the polymer molding detection device based on piezoelectric-thermocouple array and optical integration according to any one of claims 1 to 5, characterized in that: Specifically: During the micro-molding process, the polymer melt flows axially inside the measuring channel. At this time, the piezoelectric sensor array detects the pressure of the polymer melt based on the relationship between pressure and potential. The expression based on the relationship between pressure and potential is as follows: ； In the formula, P is the pressure of the polymer melt, is the potential difference between the two piezoelectric sensor arrays, is the pressure conversion coefficient, H is the thickness of the piezoelectric sensor array; The thermocouple sensor array uses the thermoelectric effect to detect the temperature of the polymer melt. The relationship between temperature and potential is expressed as follows: ； In the formula, T is the temperature of the polymer melt, is the temperature conversion coefficient, is the potential difference between the two thermocouple sensor arrays; The optical-stress measurement assembly detects the internal stress of the polymer melt, and the relationship between the number of optical fringes in the optical CCD camera and the internal stress is expressed as follows: ； Where N is the number of optical fringes, C is the photoelastic coefficient, λ is the wavelength of the incident light; σ1 is the first principal stress, i.e., the stress in the flow direction of the polymer melt; σ2 is the second principal stress, i.e., the stress perpendicular to the flow direction of the polymer melt; and t is the channel thickness of the measurement channel.

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