Plastic container molding defect detection system

Abstract

The invention discloses a plastic container molding defect detection system, belongs to the technical field of plastic container detection, and solves the problem that the production efficiency is reduced for the production of cosmetic bottles because whether the problem occurs or not can be found in a mode of matching manual quality inspection with testing during sampling inspection. Comprising a front conveyor belt and a rear conveyor belt, when the cosmetic bottle detection device works, cosmetic bottles are conveyed through the front conveying belt, and after the detection piece detects the bottles at the inner connecting plate, the inner electric push rod pushes the inner connecting plate and the multi-mode sensor probe to detect the bottles. The multi-mode sensor probe synchronously performs dielectric detection and ultrasonic reflection and feeds back bottle layer data to the defect detection system in real time, and the system judges whether the bottle layer has the interlayer debonding defect or not. If no defects exist, the bottles are conveyed to a backward conveying belt; if defects exist, the outer electric push rod pushes the outer connecting plate, so that the bottles fall from the front conveying belt and are recycled.

Description

Technical Field

[0001] The present invention relates to the technical field of plastic container detection, and particularly to a detection system for plastic container molding defects. Background Art

[0002] Plastic container mold forming is an efficient industrial production technology for manufacturing various plastic containers, such as bottles, jars, boxes, etc. The mold usually consists of two parts, namely the female mold and the male mold, which cooperate with each other during the forming process. First, the plastic raw material is heated to a molten state to form a plastic melt. Then, the melt is injected into the mold, and the plastic melt fills the mold cavity through processes such as injection molding, blow molding, or compression molding, and solidifies after cooling. The design and manufacturing precision of the mold directly affect the quality and performance of plastic containers, including dimensional accuracy, surface finish, wall thickness uniformity, etc. During the production process, parameters such as the temperature control of the mold, the injection pressure and speed of the plastic melt also need to be precisely adjusted to ensure the forming effect. In addition, the maintenance and upkeep of the mold are also very important. Regularly cleaning and inspecting the mold can extend its service life and improve production efficiency. The plastic container mold forming technology is widely used in fields such as food packaging, daily necessities, and chemical product packaging, and has the advantages of high production efficiency, low cost, and stable product quality.

[0003] Among them, cosmetic bottles are also processed through the technology of plastic container mold forming. However, in the actual operation process, the structure of multi-layer cosmetic bottles is that the outer layer is PETG and the inner layer is an EVOH barrier layer. During mass production, delamination frequently occurs at the bottle shoulder part, manifested as interface separation, emulsion leakage, and micron-level pores and unfused areas visible under a microscope.

[0004] The root cause lies in the synergistic failure of process parameters and material properties: the EVOH barrier layer needs to achieve effective bonding above 80°C, while the mold temperature of the outer layer PETG is set at 60°C, resulting in its premature cooling and solidification, forming a significant cooling rate difference with the still molten EVOH. Specifically, the shrinkage rate of PETG is 0.5% and that of EVOH is 1.5%. Shear stress is generated at the interface due to mismatched shrinkage. At the same time, an injection pressure of 60 MPa is not sufficient to ensure that the molten EVOH fully penetrates the micropores on the surface of PETG, weakening the interfacial bonding strength. Moreover, the difference in the linear expansion coefficients of PETG and EVOH further forms tensile stress during the cooling process. In addition, the design defect of the mold exhaust groove with a depth of only 0.02 mm causes gas to remain at the interface during melt filling, forming 10 - 50 μm pores, which become the starting point of delamination. These factors are coupled and amplified under the stress concentration effect at the bottle shoulder curvature mutation part, ultimately triggering a delamination problem that expands from microscopic pores to macroscopic functional failure.

[0005] Under normal circumstances, the surface defects of cosmetic bottles can be judged and identified by visual inspection technology in cooperation with a camera, so as to ensure that the product qualification rate of the final produced cosmetic bottles reaches a relatively high level. However, in the face of the problem of frequent delamination between layers at the shoulder part of multi-layer cosmetic bottles, this cannot be achieved solely by visual recognition technology. Even sampling inspection of cosmetic bottles after production is required. Only through the method of manual quality inspection in cooperation with testing during sampling inspection can it be found whether this problem has occurred. For the production of cosmetic bottles, this will lead to a decrease in production efficiency.

[0006] Therefore, a plastic container forming defect detection system is proposed to solve or alleviate the above problems. Summary of the Invention

[0007] The purpose of the present invention is to solve the deficiencies existing in the prior art and propose a plastic container forming defect detection system.

[0008] In order to achieve the above purpose, the present invention adopts the following technical solutions: A plastic container forming defect detection system includes a front conveyor belt and a rear conveyor belt arranged in sequence. On both sides of the frame of the front conveyor belt, a number of outer ring connection seats and inner ring connection seats arranged in a staggered manner are respectively fixedly connected. An outer connecting plate and an inner connecting plate that can displace along the width direction of the front conveyor belt are respectively arranged on the outer ring connection seat and the inner ring connection seat. The outer connecting plate is used to push the non-compliant cosmetic bottles on the front conveyor belt away. A multi-modal sensor probe is arranged on one of the inner connecting plates, and a detection member for detecting the passing of the cosmetic bottle is arranged on the previous sequence of the inner connecting plates, and it controls the inner connecting plate of the subsequent sequence to drive the multi-modal sensor probe to approach the cosmetic bottle. The multi-modal sensor probe is coupled to a defect detection system. The multi-modal sensor probe captures the changes in the interlayer dielectric constant and acoustic impedance of the cosmetic bottle in real time through synchronous dielectric detection and ultrasonic reflection. The defect detection system combines the changes in the interlayer dielectric constant and acoustic impedance of the cosmetic bottle fed back by the multi-modal sensor probe with hardware decision logic and adaptive environment compensation to accurately identify and sort the delamination and micro-porosity defects in multi-layer cosmetic bottles in real time.

[0009] Preferably, a first connecting vertical rod and a second connecting vertical rod are respectively fixedly connected to the outer ring connection seat and the inner ring connection seat. Through holes are respectively opened on the first connecting vertical rod and the second connecting vertical rod. An outer electric push rod and an inner electric push rod are respectively fixedly connected in the through holes of the first connecting vertical rod and the second connecting vertical rod. The outer connecting plate and the inner connecting plate are respectively fixedly connected to the movable ends of the outer electric push rod and the inner electric push rod through mounting seats.

[0010] Preferably, the detection member includes a distance sensor fixedly connected to the front side of the inner connecting plate facing the front transmission belt, and a controller coupled to the output end of the distance sensor, and the output end of the controller is coupled to the controlled end of the inner electric push rod of the subsequent sequence.

[0011] Preferably, the defect detection system includes a multi-frequency signal generator module, a resonant bridge and dynamic matching network module, a signal conditioning and demodulation module, a hardware decision logic module, a power supply and anti-interference module, and a calibration and feedback control module; The output end of the multi-frequency signal generator module is connected to the input end of the resonant bridge and dynamic matching network module, and drives the multi-modal sensor probe through an impedance matching network. The output end of the multi-modal sensor probe is connected to the input end of the signal conditioning and demodulation module. The output end of the signal conditioning and demodulation module is connected to the input end of the hardware decision logic module. The output end of the hardware decision logic module is connected to the controlled end of the outer electric push rod. The calibration and feedback control module is respectively connected to the multi-frequency signal generator module, the resonant bridge and dynamic matching network module, and the power supply and anti-interference module through the SPI bus. The power supply and anti-interference system provides multi-stage regulated power supplies for all modules.

[0012] Preferably, the multi-frequency signal generator module includes a direct digital frequency synthesizer AD9959, a phase-locked loop ADF4351, an AD8000 ultra-high-speed operational amplifier, and an operational amplifier OPA847; The first output pin of the direct digital frequency synthesizer AD9959 is connected to the non-inverting input end of the operational amplifier OPA847 through a first resistor. The VDD pin of the direct digital frequency synthesizer AD9959 is powered on, and the ground pin of the direct digital frequency synthesizer AD9959 is grounded; The output end of the operational amplifier OPA847 is connected to the drive electrode of the four-electrode dielectric probe in the multi-modal sensor probe through an impedance matching network to apply a high-frequency alternating electric field. The VS± pins of the operational amplifier OPA847 are connected to the ±12V power supply; The CLKOUT pin of the phase-locked loop ADF4351 is connected to the SYNC_IN pin of the direct digital frequency synthesizer AD9959 through a first capacitor to output a reference clock signal. The RF pin of the phase-locked loop ADF4351 is grounded after passing through a second capacitor. The VCC pin of the phase-locked loop ADF4351 is connected to the +3.3V power supply, and the ground end of the phase-locked loop ADF4351 is grounded; The inverting input terminal of the AD8000 ultra-high-speed operational amplifier is connected to the third output pin of the direct digital frequency synthesizer AD9959 through a second resistor. The output terminal of the AD8000 ultra-high-speed operational amplifier is connected to the positive electrode of the piezoelectric ceramic probe in the multi-modal sensor probe. The VS± pins of the AD8000 ultra-high-speed operational amplifier are connected to a ±12V power supply, and the non-inverting input terminal of the AD8000 ultra-high-speed operational amplifier is grounded.

[0013] Preferably, the multi-modal sensor probe includes a four-electrode dielectric probe, a piezoelectric ceramic probe, and a temperature and humidity sensor SHT35; The four-electrode dielectric probe includes two drive electrodes and two detection electrodes. Both the drive electrodes and the detection electrodes are gold-plated copper foil electrodes. One of the drive electrodes is connected to the output terminal of the operational amplifier OPA847, and the other drive electrode is grounded. One of the detection electrodes is connected to the input terminal of the signal conditioning and demodulation module to capture the interface electric field change, and the other detection electrode is connected to the dynamic matching network module through a resonant bridge. The negative electrode of the piezoelectric ceramic probe is grounded, and the echo signal output terminal of the piezoelectric ceramic probe is connected to the non-inverting input terminal of the operational amplifier AD8065 in the signal conditioning and demodulation module. Each output terminal of the temperature and humidity sensor SHT35 is connected to the microcontroller STM32F407 in the calibration and feedback control module.

[0014] Preferably, the resonant bridge and the dynamic matching network module include a resonant bridge and a dynamic matching network. The resonant bridge includes a varactor diode BBY52, a multiplexer ADG1611, and a numerically controlled inductor LPC804. The dynamic matching network includes a π-type matching network; A first inductor is connected in series between the first general input / output pin and the second general input / output pin of the numerically controlled inductor LPC804. The third general input / output pin of the numerically controlled inductor LPC804 is connected to the anode of the varactor diode BBY52. The cathode of the varactor diode BBY52 is grounded after being connected in series with a third resistor. The numerically controlled inductor LPC804 and the varactor diode BBY52 form the reference arm of the resonant bridge. The detection arm of the resonant bridge is the detection electrode in the four-electrode dielectric probe. The COM1 pin of the multiplexer ADG1611 is connected to the output of the reference arm of the resonant bridge, and the COM2 pin of the multiplexer ADG1611 is connected to the output of the detection arm of the resonant bridge. The NO1 / NO2 pins of the multiplexer ADG1611 are connected in parallel through a fourth resistor to the -IN pin of the AD8421 differential amplifier in the signal conditioning and demodulation module. The π-type matching network includes a second inductor and a third capacitor connected in series between the output terminal of the operational amplifier OPA847 and the drive electrode of the four-electrode dielectric probe in the multi-modal sensor probe. The π-type matching network is an impedance matching network.

[0015] Preferably, the signal conditioning and demodulation module includes a phase-locked amplifier AD630, a time-to-digital converter TDC7200, a band-pass filter LT1568, an AD8421 differential amplifier, an operational amplifier AD8065, and an LMH7324 comparator; The +IN pin of the AD8421 differential amplifier is connected to the detection electrode receiving interface of the four-electrode dielectric probe to receive the electric field change signal. The -IN pin of the AD8421 differential amplifier is switched to the reference arm or detection arm signal through the NO1 / NO2 pins of the multiplexer ADG1611. The OUT pin of the AD8421 differential amplifier is connected to the RinA pin of the phase-locked amplifier AD630 to output the amplified differential signal. The ±VS pins of the AD8421 differential amplifier are connected to the ±12V power supply, and the REF pin of the AD8421 differential amplifier is grounded; The REF IN pin of the phase-locked amplifier AD630 is connected to the first output pin of the direct digital frequency synthesizer AD9959 to input a 1MHz reference signal. The VOUT pin of the phase-locked amplifier AD630 is connected to the IN+ pin of the LT1016 comparator in the hardware decision logic module to output the demodulated in-phase signal. The RinB pin of the phase-locked amplifier AD630 is grounded through the fifth resistor to balance the input impedance. The CHA+ and CHA- pins of the phase-locked amplifier AD630 are grounded through the fourth capacitor to suppress common-mode noise. The CADJ1 and CADJ2 pins of the phase-locked amplifier AD630 are connected to the calibration and feedback control module. The B / A of the phase-locked amplifier AD630 is grounded. The VS± pins of the phase-locked amplifier AD630 are connected to the ±12V power supply. The SELB and SELA pins of the phase-locked amplifier AD630 are connected to the calibration and feedback control module. A sixth resistor and a seventh resistor are connected between the RA and RB pins of the phase-locked amplifier AD630 to set the internal amplifier gain. The COMP pin of the phase-locked amplifier AD630 is grounded through the fifth capacitor to stabilize the feedback loop; The START pin of the time-to-digital converter TDC7200 is connected to the output pin of the LMH7324 comparator to receive the ultrasonic echo trigger signal. The STOP pin of the time-to-digital converter TDC7200 is connected to the calibration and feedback control module to receive the stop pulse. The VDD pin of the time-to-digital converter TDC7200 is connected to the +5V power supply. The GND pin of the time-to-digital converter TDC7200 is grounded. The TIME pin of the time-to-digital converter TDC7200 outputs the time delay data to the calibration and feedback control module; The IN pin of the band-pass filter LT1568 is connected to the VOUT pin of the phase-locked amplifier AD630. The OUT pin of the band-pass filter LT1568 is connected to the IN+ pin of the LT1016 comparator in the hardware decision logic module. The VS± pin of the band-pass filter LT1568 is connected to the ±12V power supply. The GND pin of the band-pass filter LT1568 is grounded; The +IN pin of the operational amplifier AD8065 is connected to the negative electrode of the piezoelectric ceramic probe to receive the ultrasonic echo signal. The -IN pin of the operational amplifier AD8065 is grounded after being connected in series with the eighth resistor. The output pin of the operational amplifier AD8065 is connected to the IN+ pin of the LMH7324 comparator; The IN- pin of the LMH7324 comparator is connected to the first resistor voltage-dividing network. The OUT pin of the LMH7324 comparator is connected to the START pin of the time-to-digital converter TDC7200. The EN pin of the LMH7324 comparator is connected to the calibration and feedback control module.

[0016] Preferably, the hardware decision logic module includes a high-speed comparator LT1016, a four-way AND gate CD4081, and a relay driver chip ULN2003; The IN+ pin of the high-speed comparator LT1016 is connected to the VOUT pin of the phase-locked amplifier AD630. The IN- pin of the high-speed comparator LT1016 is connected with a second resistor voltage-dividing network. The OUT pin of the high-speed comparator LT1016 is connected to the A pin of the four-way AND gate CD4081. The B pin of the four-way AND gate CD4081 is connected to the calibration and feedback control module. The Y pin of the four-way AND gate CD4081 is connected to the input end of the relay driver chip ULN2003. The output end of the relay driver chip ULN2003 is connected with a relay, and the relay is coupled to an external electric push rod.

[0017] Preferably, the calibration and feedback control module includes a digital-to-analog converter AD5696R, an EEPROM memory AT24C512, and a microcontroller STM32F407; The CADJ1 and CADJ2 pins of the phase-locked amplifier AD630 are connected to the digital-to-analog converter AD5696R. The pins of the digital-to-analog converter AD5696R are all connected to the microcontroller STM32F407. The pins of the EEPROM memory AT24C512 are also all connected to the microcontroller STM32F407. The output terminals of the temperature and humidity sensor SHT35, the SELB pin and SELA pin of the phase-locked amplifier AD630, the STOP pin of the time-to-digital converter TDC7200, the TIME pin of the time-to-digital converter TDC7200, the EN pin of the LMH7324 comparator, and the B pin of the four-way AND gate CD4081 are all connected to the microcontroller STM32F407.

[0018] The present invention has the following beneficial effects: When the present invention works, the cosmetic bottle is transported by the front conveyor belt. After the detection part detects the bottle at the inner connecting plate, the inner electric push rod pushes the inner connecting plate and the multi-modal sensor probe to detect the bottle. The multi-modal sensor probe synchronizes dielectric detection and ultrasonic reflection, and real-time feedbacks the bottle layer data to the defect detection system, and the system judges whether there is an interlayer delamination defect in the bottle layer. If there is no defect, the bottle goes to the rear conveyor belt; if there is a defect, the outer electric push rod pushes the outer connecting plate to make the bottle fall from the front conveyor belt for recycling. Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as a limitation of the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0020] Figure 1 is a schematic structural diagram of the present invention; Figure 2 is a structural block diagram of the defect detection system in the present invention.

[0021] In the figure: 1. Front conveyor belt; 2. Rear conveyor belt; 301. Outer ring connection seat; 302. First connecting vertical rod; 303. Outer electric push rod; 304. Outer connecting plate; 401. Inner ring connection seat; 402. Second connecting vertical rod; 403. Inner electric push rod; 404. Inner connecting plate; 5. Multi-frequency signal generator module; 6. Multi-modal sensor probe; 7. Resonant bridge and dynamic matching network module; 8. Signal conditioning and demodulation module; 9. Hardware decision logic module; 10. Power supply and anti-interference module; 11. Calibration and feedback control module. Detailed Embodiments

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. The components of the embodiments of the present invention usually described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0024] It should be noted that: similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0025] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationships when the product of the present invention is normally placed, or the orientation or positional relationships commonly understood by those skilled in the art. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0026] In addition, the terms "first", "second", "third", etc. are only used for descriptive distinction and should not be construed as indicating or implying relative importance.

[0027] In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "installed", "connected", "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] A plastic container molding defect detection system, such as Figure 1As shown in the figure, it includes a front conveyor belt 1 and a rear conveyor belt arranged in sequence. On both sides of the frame of the front conveyor belt 1, a number of outer ring connection seats 301 and inner ring connection seats 401 arranged in a staggered manner are respectively fixedly connected. On the outer ring connection seat 301 and the inner ring connection seat 401, an outer connecting plate 304 and an inner connecting plate 404 that can be displaced along the width direction of the front conveyor belt 1 are respectively arranged. The outer connecting plate 304 is used to push the non-compliant cosmetic bottles on the front conveyor belt 1 away. A multi-modal sensor probe 6 is arranged on one of the inner connecting plates 404, and a detection component for detecting the passing of the cosmetic bottle is arranged on the previous sequence of inner connecting plates 404 and controls the next sequence of inner connecting plates 404 to drive the multi-modal sensor probe 6 close to the cosmetic bottle. The multi-modal sensor probe 6 is coupled to a defect detection system. The multi-modal sensor probe 6 captures the changes in the interlayer dielectric constant and acoustic impedance of the cosmetic bottle in real time through synchronous dielectric detection and ultrasonic reflection. The defect detection system combines the changes in the interlayer dielectric constant and acoustic impedance of the cosmetic bottle fed back by the multi-modal sensor probe 6 with hardware decision logic and adaptive environmental compensation to accurately identify and sort the interlayer delamination and micro-porosity defects in the multi-layer cosmetic bottles in real time.

[0029] A first connecting vertical rod 302 and a second connecting vertical rod 402 are respectively fixedly connected to the outer ring connection seat 301 and the inner ring connection seat 401. Through holes are respectively opened on the first connecting vertical rod 302 and the second connecting vertical rod 402. An outer electric push rod 303 and an inner electric push rod 403 are respectively fixedly connected in the through holes of the first connecting vertical rod 302 and the second connecting vertical rod 402. The outer connecting plate 304 and the inner connecting plate 404 are respectively fixedly connected to the movable ends of the outer electric push rod 303 and the inner electric push rod 403 through mounting seats. The detection component includes a distance sensor fixedly connected to the side of the inner connecting plate 404 facing the front conveyor belt, and a controller coupled to the output end of the distance sensor. The output end of the controller is coupled to the controlled end of the next sequence of inner electric push rods 403.

[0030] As Figure 2As shown in the figure, the defect detection system includes a multi-frequency signal generator module 5, a resonant bridge and dynamic matching network module 7, a signal conditioning and demodulation module 8, a hardware decision logic module 9, a power supply and anti-interference module 10, and a calibration and feedback control module 11. The output end of the multi-frequency signal generator module 5 is connected to the input end of the resonant bridge and dynamic matching network module 7, and drives the multi-modal sensor probe 6 through an impedance matching network. The output end of the multi-modal sensor probe 6 is connected to the input end of the signal conditioning and demodulation module 8. The output end of the signal conditioning and demodulation module 8 is connected to the input end of the hardware decision logic module 9. The output end of the hardware decision logic module 9 is connected to the controlled end of the external electric push rod 303. The calibration and feedback control module 11 is connected to the multi-frequency signal generator module 5, the resonant bridge and dynamic matching network module 7, and the power supply and anti-interference module 10 through the SPI bus respectively. The power supply and anti-interference system provides multi-stage regulated power supplies for all modules.

[0031] The multi-frequency signal generator module 5 includes a direct digital frequency synthesizer AD9959, a phase-locked loop ADF4351, an AD8000 ultra-high-speed operational amplifier, and an operational amplifier OPA847. The first output pin of the direct digital frequency synthesizer AD9959 is connected to the non-inverting input end of the operational amplifier OPA847 through a first resistor. The VDD pin of the direct digital frequency synthesizer AD9959 is powered on. The ground pin of the direct digital frequency synthesizer AD9959 is grounded. The output end of the operational amplifier OPA847 is connected to the drive electrode of the four-electrode dielectric probe in the multi-modal sensor probe 6 through an impedance matching network to apply a high-frequency alternating electric field. The VS± pins of the operational amplifier OPA847 are connected to the ±12V power supply. The CLKOUT pin of the phase-locked loop ADF4351 is connected to the SYNC_IN pin of the direct digital frequency synthesizer AD9959 through a first capacitor to output a reference clock signal. The RF pin of the phase-locked loop ADF4351 is grounded after passing through a second capacitor. The VCC pin of the phase-locked loop ADF4351 is connected to the +3.3V power supply. The ground terminal of the phase-locked loop ADF4351 is grounded. The inverting input end of the AD8000 ultra-high-speed operational amplifier is connected to the third output pin of the direct digital frequency synthesizer AD9959 through a second resistor. The output end of the AD8000 ultra-high-speed operational amplifier is connected to the positive electrode of the piezoelectric ceramic probe in the multi-modal sensor probe 6. The VS± pins of the AD8000 ultra-high-speed operational amplifier are connected to the ±12V power supply. The non-inverting input end of the AD8000 ultra-high-speed operational amplifier is grounded.

[0032] The multimodal sensor probe 6 includes a four-electrode dielectric probe, a piezoelectric ceramic probe, and a temperature and humidity sensor SHT35. The four-electrode dielectric probe includes two driving electrodes and two detecting electrodes. Both the driving electrodes and the detecting electrodes are gold-plated copper foil electrodes. One of the driving electrodes is connected to the output terminal of the operational amplifier OPA847, and the other driving electrode is grounded. One of the detecting electrodes is connected to the input terminal of the signal conditioning and demodulation module 8 to capture the interface electric field change. The other detecting electrode is connected to the dynamic matching network module 7 through a resonant bridge. The negative electrode of the piezoelectric ceramic probe is grounded, and the echo signal output terminal of the piezoelectric ceramic probe is connected to the non-inverting input terminal of the operational amplifier AD8065 in the signal conditioning and demodulation module 8. Each output terminal of the temperature and humidity sensor SHT35 is connected to the microcontroller STM32F407 in the calibration and feedback control module 11.

[0033] The resonant bridge and the dynamic matching network module 7 includes a resonant bridge and a dynamic matching network. The resonant bridge includes a varactor diode BBY52, a multiplexer ADG1611, and a numerically controlled inductor LPC804. The dynamic matching network includes a π-type matching network. A first inductor is connected in series between the first general input / output pin and the second general input / output pin of the numerically controlled inductor LPC804. The third general input / output pin of the numerically controlled inductor LPC804 is connected to the anode of the varactor diode BBY52. The cathode of the varactor diode BBY52 is grounded after being connected in series with a third resistor. The numerically controlled inductor LPC804 and the varactor diode BBY52 form the reference arm of the resonant bridge. The detecting arm of the resonant bridge is the detecting electrode in the four-electrode dielectric probe. The COM1 pin of the multiplexer ADG1611 is connected to the output of the reference arm of the resonant bridge. The COM2 pin of the multiplexer ADG1611 is connected to the output of the detecting arm of the resonant bridge. The NO1 / NO2 pins of the multiplexer ADG1611 are connected in parallel through a fourth resistor to the -IN pin of the AD8421 differential amplifier in the signal conditioning and demodulation module 8. The π-type matching network includes a second inductor and a third capacitor connected in series between the output terminal of the operational amplifier OPA847 and the driving electrode of the four-electrode dielectric probe in the multimodal sensor probe 6. The π-type matching network is an impedance matching network.

[0034] The signal conditioning and demodulation module 8 includes a lock-in amplifier AD630, a time-to-digital converter TDC7200, a band-pass filter LT1568, an AD8421 differential amplifier, an operational amplifier AD8065, and an LMH7324 comparator; the +IN pin of the AD8421 differential amplifier is connected to the detection electrode receiving interface of the four-electrode dielectric probe to receive the interface electric field change signal, the -IN pin of the AD8421 differential amplifier is switched to the reference arm or detection arm signal through the NO1 / NO2 pins of the multiplexer ADG1611, the OUT pin of the AD8421 differential amplifier is connected to the RinA pin of the lock-in amplifier AD630 to output the amplified differential signal, the ±VS pins of the AD8421 differential amplifier are connected to the ±12V power supply, and the REF pin of the AD8421 differential amplifier is grounded; the REF IN pin of the lock-in amplifier AD630 is connected to the first output pin of the direct digital frequency synthesizer AD9959 to input a 1MHz reference signal, the VOUT pin of the lock-in amplifier AD630 is connected to the IN+ pin of the LT1016 comparator in the hardware decision logic module 9 to output the demodulated in-phase signal, the RinB pin of the lock-in amplifier AD630 is grounded through the fifth resistor to balance the input impedance, the CHA+ and CHA- pins of the lock-in amplifier AD630 are grounded through the fourth capacitor to suppress the common-mode noise, the CADJ1 and CADJ2 pins of the lock-in amplifier AD630 are connected to the calibration and feedback control module 11, the B / A of the lock-in amplifier AD630 is grounded, the VS± pins of the lock-in amplifier AD630 are connected to the ±12V power supply, the SELB and SELA pins of the lock-in amplifier AD630 are connected to the calibration and feedback control module 11, a sixth resistor and a seventh resistor are connected between the RA and RB pins of the lock-in amplifier AD630 to set the internal amplifier gain, and the COMP pin of the lock-in amplifier AD630 is grounded through the fifth capacitor to stabilize the feedback loop; the START pin of the time-to-digital converter TDC7200 is connected to the output pin of the LMH7324 comparator to receive the ultrasonic echo trigger signal, the STOP pin of the time-to-digital converter TDC7200 is connected to the calibration and feedback control module 11 to receive the stop pulse, the VDD pin of the time-to-digital converter TDC7200 is connected to the +5V power supply, the GND pin of the time-to-digital converter TDC7200 is grounded, and the TIME pin of the time-to-digital converter TDC7200 outputs the time delay data to the calibration and feedback control module 11; the IN pin of the band-pass filter LT1568 is connected to the VOUT pin of the lock-in amplifier AD630, the OUT pin of the band-pass filter LT1568 is connected to the IN+ pin of the LT1016 comparator in the hardware decision logic module 9, the VS± pins of the band-pass filter LT1568 are connected to the ±12V power supply, and the GND pin of the band-pass filter LT1568 is grounded;The +IN pin of the operational amplifier AD8065 is connected to the negative electrode of the piezoelectric ceramic probe to receive the ultrasonic echo signal. The -IN pin of the operational amplifier AD8065 is grounded after being connected in series with the eighth resistor. The output pin of the operational amplifier AD8065 is connected to the IN+ pin of the LMH7324 comparator. The IN- pin of the LMH7324 comparator is connected to the first resistor voltage division network. The OUT pin of the LMH7324 comparator is connected to the START pin of the time-to-digital converter TDC7200. The EN pin of the LMH7324 comparator is connected to the calibration and feedback control module 11.

[0035] The hardware decision logic module 9 includes a high-speed comparator LT1016, a four-way AND gate CD4081, and a relay driver chip ULN2003. The IN+ pin of the high-speed comparator LT1016 is connected to the VOUT pin of the phase-locked amplifier AD630. The IN- pin of the high-speed comparator LT1016 is connected with a second resistor voltage division network. The OUT pin of the high-speed comparator LT1016 is connected to the A pin of the four-way AND gate CD4081. The B pin of the four-way AND gate CD4081 is connected to the calibration and feedback control module 11. The Y pin of the four-way AND gate CD4081 is connected to the input end of the relay driver chip ULN2003. The output end of the relay driver chip ULN2003 is connected with a relay, and the relay is coupled to the external electric push rod 303.

[0036] The power supply and anti-interference module 10 includes a low-dropout regulator LT3045 and a high-PSRR regulator TPS7A4701. The input end of the low-dropout regulator LT3045 is connected to a 24V power supply. The output end of the low-dropout regulator LT3045 provides a 5V power supply. The input end of the high-PSRR regulator TPS7A4701 is connected to a 24V power supply. The output end of the high-PSRR regulator TPS7A4701 provides a 12V power supply.

[0037] The calibration and feedback control module 11 includes a digital-to-analog converter AD5696R, an EEPROM memory AT24C512, and a microcontroller STM32F407. The CADJ1 and CADJ2 pins of the phase-locked amplifier AD630 are connected to the digital-to-analog converter AD5696R. The pins of the digital-to-analog converter AD5696R are all connected to the microcontroller STM32F407. The pins of the EEPROM memory AT24C512 are also all connected to the microcontroller STM32F407. The output ends of the temperature and humidity sensor SHT35, the SELB pin and SELA pin of the phase-locked amplifier AD630, the STOP pin of the time-to-digital converter TDC7200, the TIME pin of the time-to-digital converter TDC7200, the EN pin of the LMH7324 comparator, and the B pin of the four-way AND gate CD4081 are all connected to the microcontroller STM32F407.

[0038] When the present invention is working, the cosmetic bottle is transported through the front conveyor belt 1. When it passes through the position where an inner connecting plate 404 is located, the detector detects its presence. Then, a series of inner electric push rods 403 push the inner connecting plate 404 and the multi-modal sensor probe 6 thereon to detect the cosmetic bottle. The multi-modal sensor probe 6 synchronously performs dielectric detection and ultrasonic reflection on the cosmetic bottle to capture the changes in the interlayer dielectric constant and acoustic impedance of the cosmetic bottle in real time and feedback them to the defect detection system. Thereby, the defect detection system can determine whether there is a defect in the cosmetic bottle layer corresponding to the frequent occurrence of interlayer debonding at the bottle shoulder part. If not, then the cosmetic bottle smoothly goes to the rear conveyor belt for transfer. If so, then the outer electric push rod 303 is controlled to push the outer connecting plate 304, so that the cosmetic bottle with this defect can fall off the front conveyor belt 1 for recycling, avoiding the situation where defects cannot be detected.

[0039] When the specific defect detection system is working, The working process of the plastic container delamination defect detection circuit based on multi-modal sensing takes the interlayer debonding problem of a multi-layer cosmetic bottle (the outer layer is PETG and the inner layer is an EVOH barrier layer) as the core detection target. Its detailed working process is as follows: After the system is powered on, the direct digital frequency synthesizer AD9959 in the multi-frequency signal generator module 5 receives instructions from the microcontroller STM32F407 through the SPI bus, starts the dynamic frequency sweeping mode. The first output pin of the direct digital frequency synthesizer AD9959 outputs a 1MHz sine wave signal. After being amplified by the operational amplifier OPA847, it drives a four-electrode dielectric probe through a π-type matching network. Among them, an alternating electric field is applied to the driving electrode of the four-electrode dielectric probe to penetrate the bottle body to the EVOH layer interface, and the detection electrode of the four-electrode dielectric probe captures the local change in the dielectric constant caused by interlayer debonding or air holes. At the same time, the third output pin of the direct digital frequency synthesizer AD9959 outputs a frequency sweeping signal. This signal is amplified by the ultra-high-speed operation amplifier of the AD8000 ultra-high-speed operational amplifier and then drives the piezoelectric ceramic probe to emit ultrasonic pulses.

[0040] At this time, the inner layer of the double-layer shielded coaxial line in the multi-modal sensor probe 6 module transmits ultrasonic signals, and the detection electrode of the four-electrode dielectric probe monitors the electric field distribution at the PETG / EVOH interface in real time. If there is interlayer debonding or air holes, the equivalent capacitance value of the interface will decrease by 0.5% - 15%. This change is amplified by the AD8421 differential amplifier and then input into the lock-in amplifier AD630 for coherent demodulation with the 1MHz reference signal at the first output pin of the direct digital frequency synthesizer AD9959, and the X component is output to the LT1016 comparator. The X component reflects the amplitude of the change in the dielectric constant.

[0041] Meanwhile, after the ultrasonic echo signal is amplified by the operational amplifier AD8065, it is converted into digital pulses by the comparator LMH7324, triggering the time-to-digital converter TDC7200 to measure the time delay difference between the transmitted wave and the echo. This time delay data is input through the microcontroller STM32F407.

[0042] In the hardware decision logic module 9, the comparator LT1016 compares the X component output by the lock-in amplifier AD630 with the threshold value. At the same time, the microcontroller STM32F407 analyzes the time delay data of the time-to-digital converter TDC7200. If it is detected that the time delay difference of the echo is less than the threshold value and the voltage of the X component is greater than the threshold value, the four-way AND gate CD4081 outputs a high level to trigger the relay driver chip ULN2003, and the external electric push rod 303 works to remove the defective bottle body.

[0043] In the power supply and anti-interference module 10, the low-dropout regulator LT3045 provides a low-noise 5V digital power supply, and the high PSRR regulator TPS7A4701 outputs ±12V analog power supplies. Throughout the process, the microcontroller STM32F407 reads the data of the temperature and humidity sensor SHT35 every 15 minutes to dynamically correct the dielectric detection threshold. For every 1°C increase in temperature, the dielectric constant of EVOH decreases by 0.3%. The reference arm capacitor of the resonant bridge is fine-tuned through the digital-to-analog converter AD5696R to achieve full-automatic environmental compensation. Finally, the system can stably detect to ensure the quality of the final cosmetic bottles produced.

[0044] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A plastic container forming defect detection system, comprising a front conveyor belt and a rear conveyor belt arranged in sequence, and a plurality of outer ring connection seats and inner ring connection seats which are arranged in a staggered manner are fixedly connected to both sides of the frame of the front conveyor belt respectively, and is characterized in that, The outer ring connection base and the inner ring connection base are respectively provided with an outer connecting plate and an inner connecting plate that can be displaced along the width direction of the front conveyor belt. The outer connecting plate is used to push the non-compliant cosmetic bottles on the front conveyor belt away. A multimodal sensor probe is provided on one of the inner connecting plates, and a detection member for detecting the passing of the cosmetic bottle is provided on the inner connecting plate of the previous sequence and controls the inner connecting plate of the subsequent sequence to drive the multimodal sensor probe close to the cosmetic bottle. The multimodal sensor probe is coupled to a defect detection system. The multimodal sensor probe captures the changes in the interlayer dielectric constant and acoustic impedance of the cosmetic bottle in real time through synchronous dielectric detection and ultrasonic reflection. The defect detection system combines the changes in the interlayer dielectric constant and acoustic impedance of the cosmetic bottle fed back by the multimodal sensor probe with hardware decision logic and adaptive environment compensation to accurately identify and sort the interlayer delamination and micro-porosity defects in the multi-layer cosmetic bottles in real time.

2. The plastic container forming defect detection system according to claim 1, characterized in that, A first connecting vertical rod and a second connecting vertical rod are respectively fixedly connected to the outer ring connection base and the inner ring connection base. Through holes are respectively formed in the first connecting vertical rod and the second connecting vertical rod. An outer electric push rod and an inner electric push rod are respectively fixedly connected in the through holes of the first connecting vertical rod and the second connecting vertical rod. The outer connecting plate and the inner connecting plate are respectively fixedly connected to the movable ends of the outer electric push rod and the inner electric push rod through mounting seats.

3. The plastic container molding defect detection system according to claim 2, characterized in that, The detection member includes a distance sensor fixedly connected to the side of the inner connecting plate facing the front conveyor belt, and a controller coupled to the output end of the distance sensor. The output end of the controller is coupled to the controlled end of the inner electric push rod of the subsequent sequence.

4. A plastic container forming defect detection system according to claim 2, wherein The defect detection system includes a multi-frequency signal generator module, a resonant bridge and dynamic matching network module, a signal conditioning and demodulation module, a hardware decision logic module, a power supply and anti-interference module, and a calibration and feedback control module; The output end of the multi-frequency signal generator module is connected to the input end of the resonant bridge and dynamic matching network module, and drives the multimodal sensor probe through an impedance matching network. The output end of the multimodal sensor probe is connected to the input end of the signal conditioning and demodulation module. The output end of the signal conditioning and demodulation module is connected to the input end of the hardware decision logic module. The output end of the hardware decision logic module is connected to the controlled end of the outer electric push rod. The calibration and feedback control module is respectively connected to the multi-frequency signal generator module, the resonant bridge and dynamic matching network module, and the power supply and anti-interference module through the SPI bus. The power supply and anti-interference system provides a multi-stage regulated power supply for all modules.

5. A plastic container forming defect detection system according to claim 4, characterized in that, The multi-frequency signal generator module includes a direct digital frequency synthesizer AD9959, a phase-locked loop ADF4351, an AD8000 ultra-high-speed operational amplifier, and an operational amplifier OPA847; The first output pin of the direct digital frequency synthesizer AD9959 is connected to the non-inverting input end of the operational amplifier OPA847 through a first resistor. The VDD pin of the direct digital frequency synthesizer AD9959 is powered on, and the ground pin of the direct digital frequency synthesizer AD9959 is grounded. The output terminal of the operational amplifier OPA847 is connected to the drive electrode of the four-electrode dielectric probe in the multi-modal sensor probe through an impedance matching network to apply a high-frequency alternating electric field. The VS± pins of the operational amplifier OPA847 are connected to the ±12V power supply; The CLKOUT pin of the phase-locked loop ADF4351 is connected to the SYNC_IN pin of the direct digital frequency synthesizer AD9959 through a first capacitor to output a reference clock signal. The RF pin of the phase-locked loop ADF4351 is grounded after passing through a second capacitor. The VCC pin of the phase-locked loop ADF4351 is connected to the +3.3V power supply, and the ground terminal of the phase-locked loop ADF4351 is grounded; The inverting input terminal of the AD8000 ultra-high-speed operational amplifier is connected to the third output pin of the direct digital frequency synthesizer AD9959 through a second resistor. The output terminal of the AD8000 ultra-high-speed operational amplifier is connected to the positive electrode of the piezoelectric ceramic probe in the multi-modal sensor probe. The VS± pins of the AD8000 ultra-high-speed operational amplifier are connected to the ±12V power supply, and the non-inverting input terminal of the AD8000 ultra-high-speed operational amplifier is grounded.

6. The plastic container molding defect detection system according to claim 4, characterized in that, The multi-modal sensor probe includes a four-electrode dielectric probe, a piezoelectric ceramic probe, and a temperature and humidity sensor SHT35; The four-electrode dielectric probe includes two drive electrodes and two detection electrodes. The drive electrodes and the detection electrodes are both gold-plated copper foil electrodes. One of the drive electrodes is connected to the output terminal of the operational amplifier OPA847, and the other drive electrode is grounded. One of the detection electrodes is connected to the input terminal of the signal conditioning and demodulation module to capture the interface electric field change. The other detection electrode is connected to the dynamic matching network module through a resonant bridge. The negative electrode of the piezoelectric ceramic probe is grounded. The echo signal output terminal of the piezoelectric ceramic probe is connected to the non-inverting input terminal of the operational amplifier AD8065 in the signal conditioning and demodulation module. Each output terminal of the temperature and humidity sensor SHT35 is connected to the microcontroller STM32F407 in the calibration and feedback control module.

7. A plastic container molding defect detection system according to claim 4, characterized in that, The resonant bridge and the dynamic matching network module include a resonant bridge and a dynamic matching network. The resonant bridge includes a varactor diode BBY52, a multiplexer ADG1611, and a numerically controlled inductor LPC804. The dynamic matching network includes a π-type matching network; A first inductor is connected in series between the first general-purpose input / output pin and the second general-purpose input / output pin of the digital control inductor LPC804. The third general-purpose input / output pin of the digital control inductor LPC804 is connected to the anode of the varactor diode BBY52. The cathode of the varactor diode BBY52 is grounded after being connected in series with a third resistor. The digital control inductor LPC804 and the varactor diode BBY52 form a reference arm of a resonant bridge. The detection arm of the resonant bridge is the detection electrode in a four-electrode dielectric probe. The COM1 pin of the multiplexer ADG1611 is connected to the output of the reference arm of the resonant bridge. The COM2 pin of the multiplexer ADG1611 is connected to the output of the detection arm of the resonant bridge. The NO1 / NO2 pins of the multiplexer ADG1611 are connected in parallel through a fourth resistor to the -IN pin of the AD8421 differential amplifier in the signal conditioning and demodulation module. The π-type matching network includes a second inductor and a third capacitor connected in series between the output terminal of the operational amplifier OPA847 and the drive electrode of the four-electrode dielectric probe in the multimodal sensor probe. The π-type matching network is an impedance matching network.

8. A plastic container molding defect detection system according to claim 4, characterized in that, The signal conditioning and demodulation module includes a lock-in amplifier AD630, a time-to-digital converter TDC7200, a band-pass filter LT1568, an AD8421 differential amplifier, an operational amplifier AD8065, and an LMH7324 comparator. The +IN pin of the AD8421 differential amplifier is connected to the detection electrode of the four-electrode dielectric probe to receive the interface electric field change signal. The -IN pin of the AD8421 differential amplifier is switched to the reference arm or the detection arm signal through the NO1 / NO2 pins of the multiplexer ADG1611. The OUT pin of the AD8421 differential amplifier is connected to the RinA pin of the lock-in amplifier AD630 to output the amplified differential signal. The ±VS pins of the AD8421 differential amplifier are connected to the ±12V power supply. The REF pin of the AD8421 differential amplifier is grounded. The REF IN pin of the phase-locked amplifier AD630 is connected to the first output pin of the direct digital frequency synthesizer AD9959 to input a 1 MHz reference signal. The VOUT pin of the phase-locked amplifier AD630 is connected to the IN+ pin of the LT1016 comparator in the hardware decision logic module to output the demodulated in-phase signal. The RinB pin of the phase-locked amplifier AD630 is grounded through the fifth resistor to balance the input impedance. The CHA+ pin and CHA- pin of the phase-locked amplifier AD630 are grounded through the fourth capacitor to suppress common-mode noise. The CADJ1 and CADJ2 pins of the phase-locked amplifier AD630 are connected to the calibration and feedback control module. The B / A of the phase-locked amplifier AD630 is grounded. The VS± pins of the phase-locked amplifier AD630 are connected to the ±12V power supply. The SELB pin and SELA pin of the phase-locked amplifier AD630 are connected to the calibration and feedback control module. A sixth resistor and a seventh resistor are connected between the RA pin and RB pin of the phase-locked amplifier AD630 to set the internal amplifier gain. The COMP pin of the phase-locked amplifier AD630 is grounded through the fifth capacitor to stabilize the feedback loop; The START pin of the time-to-digital converter TDC7200 is connected to the output pin of the LMH7324 comparator to receive the ultrasonic echo trigger signal. The STOP pin of the time-to-digital converter TDC7200 is connected to the calibration and feedback control module to receive the stop pulse. The VDD pin of the time-to-digital converter TDC7200 is connected to the +5V power supply. The GND pin of the time-to-digital converter TDC7200 is grounded. The TIME pin of the time-to-digital converter TDC7200 outputs the time delay data to the calibration and feedback control module; The IN pin of the band-pass filter LT1568 is connected to the VOUT pin of the phase-locked amplifier AD630. The OUT pin of the band-pass filter LT1568 is connected to the IN+ pin of the LT1016 comparator in the hardware decision logic module. The VS± pins of the band-pass filter LT1568 are connected to the ±12V power supply. The GND pin of the band-pass filter LT1568 is grounded; The +IN pin of the operational amplifier AD8065 is connected to the negative electrode of the piezoelectric ceramic probe to receive the ultrasonic echo signal. The -IN pin of the operational amplifier AD8065 is grounded after being connected in series with the eighth resistor. The output pin of the operational amplifier AD8065 is connected to the IN+ pin of the LMH7324 comparator; The IN- pin of the LMH7324 comparator is connected to the first resistor voltage divider network. The OUT pin of the LMH7324 comparator is connected to the START pin of the time-to-digital converter TDC7200. The EN pin of the LMH7324 comparator is connected to the calibration and feedback control module.

9. A plastic container molding defect detection system according to claim 4, characterized in that, The hardware decision logic module includes a high-speed comparator LT1016, a four-way AND gate CD4081, and a relay driver chip ULN2003; The IN+ pin of the high-speed comparator LT1016 is connected to the VOUT pin of the lock-in amplifier AD630. The IN- pin of the high-speed comparator LT1016 is connected to a second resistor voltage-dividing network. The OUT pin of the high-speed comparator LT1016 is connected to the A pin of the four-way AND gate CD4081. The B pin of the four-way AND gate CD4081 is connected to the calibration and feedback control module. The Y pin of the four-way AND gate CD4081 is connected to the input end of the relay driver chip ULN2003. The output end of the relay driver chip ULN2003 is connected to a relay, and the relay is coupled to an external electric push rod.

10. A plastic container forming defect detection system according to claim 4, characterized in that, The calibration and feedback control module includes a digital-to-analog converter AD5696R, an EEPROM memory AT24C512, and a microcontroller STM32F407. The CADJ1 and CADJ2 pins of the lock-in amplifier AD630 are connected to the digital-to-analog converter AD5696R. The pins of the digital-to-analog converter AD5696R are all connected to the microcontroller STM32F407. The pins of the EEPROM memory AT24C512 are also all connected to the microcontroller STM32F407. The output terminals of the temperature and humidity sensor SHT35, the SELB pin and SELA pin of the lock-in amplifier AD630, the STOP pin of the time-to-digital converter TDC7200, the TIME pin of the time-to-digital converter TDC7200, the EN pin of the LMH7324 comparator, and the B pin of the four-way AND gate CD4081 are all connected to the microcontroller STM32F407.

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