Microcellular foam molding visual monitoring device

Abstract

The present application provides a visual monitoring device for microporous foam molding, comprising: a molding unit, comprising a detachably connected upper die and a lower die, a through molding cavity formed between the upper die and the lower die along the molding direction, a transparent plate provided on the top of the molding cavity along the molding direction, the transparent plate fixed to the bottom of the upper die, a transparent pressing block provided along the molding direction abutting the transparent plate above the transparent plate, the top of the transparent pressing block passing through the upper die; a video acquisition unit provided above the transparent pressing block, configured to acquire product image information within the molding cavity through the transparent pressing block and the transparent plate. The visual monitoring device for microporous foam molding provided in the present application has a simple structure, is convenient for observing and acquiring product image information, is low in cost, can visually display the foaming molding process of a polymer melt / supercritical fluid homogeneous system, and provides a reliable basis for optimizing foaming process parameters.

Description

Technical Field

[0001] The present application relates to the field of microporous foaming technology, and in particular to a visual monitoring device for microporous foaming molding. Background Art

[0002] Plastic processing using foaming technology can reduce the weight of products. Microporous foam plastics refer to foams with a diameter of less than 10 μm and a density of 10 9 -10 15 pieces / cm 3 A new type of plastic can be widely used in military and transportation support equipment. The performance of microcellular foam products is closely related to the morphology of the bubbles. During the foaming molding process of the polymer melt / supercritical fluid homogeneous system, its rheological behavior, mold filling process and bubble evolution process all directly affect the final bubble morphology. However, the existing foaming molding device is not visual and cannot observe the foaming molding process of the product in real time. Summary of the Invention

[0003] In view of this, the purpose of this application is to propose a visual monitoring device for microcellular foam molding to solve the related problems mentioned in the background technology.

[0004] The present application provides a visual monitoring device for microcellular foam molding, comprising: a molding unit, comprising a detachably connected upper mold and a lower mold, a through molding cavity formed between the upper mold and the lower mold along the molding direction, a transparent plate provided on the top of the molding cavity along the molding direction, the transparent plate fixed to the bottom of the upper mold, a transparent pressure block provided along the molding direction abutting the top of the transparent plate, the top of the transparent pressure block passing through the upper mold; a camera acquisition unit, arranged above the transparent pressure block, configured to acquire product image information in the molding cavity through the transparent pressure block and the transparent plate.

[0005] Furthermore, the microporous foam molding visual monitoring device also includes: a testing unit, including a sampling plate, which is arranged at the bottom of the molding cavity along the molding direction and fixed on the top of the lower mold, and a through capillary channel is provided inside the sampling plate along the molding direction, and both ends of the capillary channel are connected to the inside of the molding cavity, and test sensors are provided at intervals at the bottom of the capillary channel along the molding direction.

[0006] Furthermore, the test sensor includes a first pressure sensor and a temperature sensor.

[0007] Furthermore, the video acquisition unit includes: a camera, arranged above the transparent pressing block and installed on a universal bracket, with an optical microscope provided at the bottom of the camera; a light source, arranged on the side of the camera and located above the transparent pressing block.

[0008] Furthermore, a pressure valve is provided at the outlet of the molding cavity, and a limiting piece is provided at the top of the upper die.

[0009] Furthermore, the microcellular foam molding visual monitoring device also includes: an injection unit, connected to the inlet of the molding cavity; a supercritical fluid generating unit, connected to the injection unit; a molding unit, connected to the outlet of the molding cavity, a traction device is provided at the outlet of the molding unit, and a cutting device is provided at the outlet of the traction device.

[0010] Furthermore, the molding unit further includes: a cooling device, which is arranged on the top of the upper die and / or the bottom of the lower die; and a heating device, which is arranged on the side walls of the upper die and the lower die.

[0011] Furthermore, the heating device is a condenser, the cooling device is an evaporator, the supercritical fluid generating unit is connected to the inlet of the condenser, the outlet of the condenser is connected to the inlet of the evaporator, a throttle valve is connected between the condenser and the evaporator, and the outlet of the evaporator is connected to the gas storage bottle of the supercritical fluid generating unit.

[0012] Furthermore, the molding unit includes: an upper molding box and a lower molding box that are detachably connected, with a molding channel formed therebetween running along the molding direction, a first coolant contained inside the upper molding box and the lower molding box, the inlet of the molding channel being connected to the outlet of the molding cavity; a cooling box containing a second coolant, the side wall of the cooling box being provided with a feed port and a discharge port along the molding direction, the feed port being opposite to the outlet of the molding channel, and a sealing member being provided on the feed port and the discharge port respectively.

[0013] Furthermore, the injection unit includes: a barrel, a side wall of which is provided with a second pressure sensor.

[0014] From the above description, it can be seen that the microporous foaming molding visualization monitoring device provided by the present application can visually display the foaming molding process of the polymer melt / supercritical fluid homogeneous system in the molding cavity by setting a transparent plate and a transparent pressing block; the camera acquisition unit is set to collect product image information through the transparent plate and the transparent pressing block, and directly monitor and analyze the filling process and foaming process of the polymer melt / supercritical fluid homogeneous system, so as to understand the product foaming situation and surface defects in real time, adjust the process parameters in time, and improve product quality; the transparent pressing block can rely on gravity to provide downward pressure for the transparent plate, increase the strength of the transparent plate, and prevent the transparent plate from being damaged by excessive pressure in the molding cavity; the microporous foaming molding visualization monitoring device has a simple structure, is easy to observe and collect product image information, is low in cost, can visually display the foaming molding process of the polymer melt / supercritical fluid homogeneous system, and provide a reliable basis for optimizing the foaming process parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in this application or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are merely embodiments of this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0016] Figure 1 Schematic diagram of the cross-sectional structure of a visual monitoring device for microcellular foam molding along the molding direction according to an embodiment of the present application;

[0017] Figure 2 This is a schematic diagram of the cross-sectional structure of a visual monitoring device for microcellular foam molding according to an embodiment of the present application, perpendicular to the molding direction;

[0018] Figure 3 This is a schematic diagram of the cross-sectional structure of another microcellular foam molding visual monitoring device according to an embodiment of the present application, perpendicular to the molding direction;

[0019] Figure 4 This is a schematic structural diagram of another microcellular foam molding visual monitoring device according to an embodiment of the present application along the molding direction;

[0020] Figure 5 Schematic diagram of the cross-sectional structure of the shaping unit according to an embodiment of the present application;

[0021] Figure 6 This is a connection diagram of a computer terminal according to an embodiment of the present application.

[0022] Reference numerals: 1, molding unit; 1-1, upper die; 1-2, lower die; 1-3, molding cavity; 1-4, transparent plate; 1-5, transparent pressing block; 1-6, cooling device; 1-7, limiter; 1-8, pressure valve; 1-9, heating device;

[0023] 2. Video acquisition unit; 2-1. Camera; 2-2. Universal bracket; 2-3. Optical microscope; 2-4. Light source;

[0024] 3. Test unit; 3-1. Sampling plate; 3-2. Capillary tube; 3-3. Test sensor;

[0025] 4. Injection unit; 4-1. Barrel; 4-2. Second pressure sensor;

[0026] 5. Supercritical fluid generation unit; 5-1. First valve; 5-2. Second valve; 5-3. Vaporization chamber; 5-4. Throttle valve; 5-5. Gas cylinder;

[0027] 6. Forming unit; 6-1. Upper forming box; 6-2. Lower forming box; 6-3. Forming channel; 6-4. First coolant; 6-5. Cooling box; 6-6. Second coolant; 6-7. Feed port; 6-8. Discharge port; 6-9. Sealing element;

[0028] 7. Traction device; 8. Cutting device; 9. Computer terminal; 10. Product. DETAILED DESCRIPTION

[0029] In order to make the objectives, technical solutions and advantages of this application more clear, this application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0030] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should have the usual meanings understood by people with ordinary skills in the field to which this application belongs. The "first", "second" and similar words used in the embodiments of the present application do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0031] Plastics processing uses foaming technology to reduce the weight of finished products, but traditional foaming processes use petroleum gas (such as butane and pentane) as a foaming agent. With the increasing prominence of environmental and production safety issues, the demand for new foaming agents that are energy-saving, environmentally friendly, safe, and stable continues to expand. In recent years, microcellular foaming technology has gained widespread application. Under normal conditions, the amount of carbon dioxide or nitrogen dissolved in molten resin is very small, insufficient for foaming. However, under supercritical conditions, the solubility and diffusion rate of carbon dioxide or nitrogen will be greatly increased, thus fully meeting the process conditions required for microcellular foaming. With the support of comprehensive process technology and equipment, supercritical gas can achieve the perfect microcellular foaming effect.

[0032] Microporous foaming technology first mixes / diffuses supercritical carbon dioxide or nitrogen with the polymer melt to form a polymer melt / supercritical fluid homogeneous system: the polymer melt / supercritical fluid homogeneous system is introduced into the mold cavity or die, generating a huge pressure drop, thereby causing a large number of bubble nuclei to precipitate inside. During the subsequent cooling and molding process, the internal bubble nuclei continue to grow and take shape, ultimately obtaining a microporous foamed plastic product.

[0033] The diameter of the pores of microporous foamed plastics is less than 10 μm, and the pore density is 10 9 -10 15 pieces / cm 3 The unique structure of microporous foam plastic gives it excellent impact strength, specific strength, toughness, thermal stability and fatigue resistance. It also has the advantages of low dielectric constant, low thermal conductivity, heat insulation and sound insulation. It can be used as thermal insulation material, packaging material and lightweight sound insulation, pressure-resistant and earthquake-resistant material, etc., and is widely used in transportation support equipment.

[0034] The performance of microcellular foamed products is closely related to the morphology of the cells. During the foaming molding process of the polymer melt / supercritical fluid homogeneous system, its rheological behavior, mold filling process, and bubble evolution process all directly affect the final cell morphology. However, the existing foaming molding equipment is not visual and cannot observe the foaming molding process of the product in real time. In addition, the existing equipment cannot obtain the rheological characteristics of the homogeneous system during the foaming molding process, lacking a basis for adjusting and optimizing the process parameters.

[0035] In the process of realizing the present invention, it was found that it is possible to consider visual design of the foaming molding device and collect product image information during the foaming molding process in real time; and to monitor the pressure and temperature of the product at different positions during the foaming molding process, and deduce the rheological characteristics of the homogeneous system, so as to guide the adjustment of process parameters.

[0036] Below, through specific embodiments and combined Figure 1-5 The technical solution of the present invention is further described in detail.

[0037] Some embodiments of the present invention provide a visual monitoring device for microcellular foaming molding, such as Figure 1 and Figure 2 As shown, it includes: a molding unit 1, including a detachably connected upper mold 1-1 and a lower mold 1-2, a through molding cavity 1-3 is formed between the upper mold 1-1 and the lower mold 1-2 along the molding direction, a transparent plate 1-4 is provided on the top of the molding cavity 1-3 along the molding direction, the transparent plate 1-4 is fixed to the bottom of the upper mold 1-1, a transparent pressing block 1-5 arranged along the molding direction is abutted above the transparent plate 1-4, and the top of the transparent pressing block 1-5 passes through the upper mold 1-1; a camera acquisition unit 2, arranged above the transparent pressing block 1-5, and configured to collect product image information in the molding cavity 1-3 through the transparent pressing block 1-5 and the transparent plate 1-4.

[0038] The molding direction is the direction from the inlet to the outlet of the molding unit 1.

[0039] The transparent plate 1-4 is made of colorless sapphire material, which not only has high strength and high thermal conductivity, but also can meet the high temperature and high pressure requirements in the microporous foaming molding process. In addition, the colorless sapphire material has excellent optical properties and can meet the needs of visual observation. In some embodiments, a protrusion is provided at the bottom of the upper mold 1-1, and the transparent plate 1-4 can be fastened to the protrusion by bolts.

[0040] The transparent pressing block 1-5 can be made of silica material, which has good thermal insulation effect and prevents the temperature of the upper mold 1-1 from dissipating; the transparent pressing block 1-5 is in contact with the transparent plate 1-4, and can rely on gravity to provide downward pressure for the transparent plate 1-4, thereby improving the strength of the transparent plate 1-4, preventing the local pressure in the molding cavity 1-3 from being too high and causing damage to the transparent plate 1-4, thereby extending the service life of the transparent plate 1-4 and not affecting the visualization effect of the transparent plate 1-4.

[0041] By arranging the transparent plate 1-4 and the transparent pressing block 1-5, a visual channel is formed above the molding cavity 1-3, and the foaming molding of the homogeneous system is not affected, and the foaming molding process of the polymer melt / supercritical fluid homogeneous system in the molding cavity 1-3 can be visually displayed.

[0042] By setting up the camera acquisition unit 2, product image information can be collected through the transparent plates 1-4 and the transparent pressing blocks 1-5, and the filling process and foaming process of the polymer melt / supercritical fluid homogeneous system can be directly monitored, which is convenient for analyzing the flow behavior of the homogeneous system and the evolution process of the foam cells. The foaming situation and surface defects of the product can be understood in real time, providing a reliable scientific basis for optimizing the foaming process parameters, facilitating timely adjustment of the process parameters, and improving product quality.

[0043] The microcellular foaming molding visualization monitoring device has a simple structure, is easy to observe and collect product image information, is low-cost, and can visualize the foaming molding process of the polymer melt / supercritical fluid homogeneous system, providing a reliable basis for optimizing foaming process parameters. It greatly shortens the process debugging time of the product, avoids repeated trial mold testing, reduces the production cost of the product, improves production efficiency, and has universal applicability.

[0044] In some embodiments, as Figure 1 and Figure 2 As shown, the microcellular foam molding visual monitoring device also includes: a testing unit 3, including a sampling plate 3-1, the sampling plate 3-1 is arranged at the bottom of the molding cavity 1-3 along the molding direction, and is fixed on the top of the lower die 1-2, and a through capillary channel 3-2 is provided inside the sampling plate 3-1 along the molding direction, both ends of the capillary channel 3-2 are connected to the interior of the molding cavity 1-3, and test sensors 3-3 are provided at intervals along the molding direction.

[0045] The sampling plate 3-1 can be fastened to the top of the lower die 1-2 by bolts. The setting of the sampling plate 3-1 can perform micro-sampling of the polymer melt / supercritical fluid homogeneous system in the molding cavity 1-3 without affecting the flow of the remaining homogeneous system in the molding cavity 1-3 and without hindering the production process of the product.

[0046] The cross-section of the capillary channel 3-2 can be circular and the diameter can be 1-10 mm, which is not specifically limited. The inlet of the capillary channel 3-2 can be trumpet-shaped to facilitate the inflow of the homogeneous system and avoid affecting the product quality; the inlet of the capillary channel 3-2 is connected to the inlet of the molding cavity 1-3, and the outlet of the capillary channel 3-2 is connected to the outlet of the molding cavity 1-3. A small amount of homogeneous system flows into the capillary channel 3-2 for data monitoring and then flows out of the capillary channel 3-2 to merge with the remaining homogeneous system in the molding cavity 1-3, which will not reduce the output.

[0047] The homogeneous system performs the foaming molding process simultaneously in the capillary channel 3-2 and the molding cavity 1-3. The monitoring data measured in the capillary channel 3-2 can represent the monitoring data of the corresponding position in the molding cavity 1-3. By real-time analysis of the monitoring data and the product image information collected at the corresponding position, the process parameters can be adjusted in time to improve product quality. The process parameters include temperature or pressure, etc., which are not specifically limited.

[0048] The capillary channel 3-2 and the test sensor 3-3 cooperate to act as a capillary slit rheometer. The fluid environment in the capillary channel 3-2 is closer to the real environment, which improves the accuracy of the test rheological parameters and has a wide measurement range. The rheological parameters include viscosity, shear stress, etc., which are not specifically limited. By using capillary channels 3-2 of different sizes in combination with test sensors 3-3 of different ranges, the rheological properties of different homogeneous systems can be measured. The rheological properties include the relationship between viscosity and pressure, etc., which are not specifically limited.

[0049] By real-time monitoring of the data of the bubble evolution process, the relationship between the process parameters, the rheological properties of the polymer melt / supercritical fluid homogeneous system and the bubble morphology in the microcellular foaming molding process is explored, and the foaming behavior of the homogeneous system is analyzed and predicted. This provides a basis for evaluating the homogeneous system formula, seeking the optimal molding process conditions and optimizing product quality, which has important theoretical and practical application value for the research on microcellular foaming molding technology.

[0050] The test sensors 3-3 are arranged in multiple groups at intervals, and the test sensors 3-3 include a first pressure sensor and a temperature sensor, such as Figure 1As shown, a total of four groups of first pressure sensors and temperature sensors are set, among which the first group of first pressure sensors and temperature sensors are set at the inlet of the capillary channel 3-2, and can correspondingly measure the pressure and temperature of the inlet of the molding cavity 1-3; along the molding direction, a second group of first pressure sensors and temperature sensors are set at the front section of the capillary channel 3-2, a third group of first pressure sensors and temperature sensors are set at the middle section of the capillary channel 3-2, and a fourth group of first pressure sensors and temperature sensors are set at the rear section of the capillary channel 3-2, so that the pressure and temperature of each section of the homogeneous system in the molding cavity 1-3 can be correspondingly measured.

[0051] The distance between the test sensor 3-3 and the outlet of the capillary tube 3-2 is l, and the pressure measured by the first pressure sensor is P. The pressures measured by the test sensor 3-3 at different positions and the corresponding distances are linearly deduced to obtain the expression of the relationship between pressure and distance of the homogeneous system, as shown in formula (1), where a, b and c are constants.

[0052] P(l)=a+bl+cl 2 (1)

[0053] In some embodiments, as Figure 2 As shown, the cross section of the capillary channel 3-2 is rectangular, the cross section width is B, and the cross section height is H. Then the shear rate D of the homogeneous system is as shown in formula (2), where Q is the flow rate of the homogeneous system, which can be measured by the injection unit 4.

[0054]

[0055] The shear stress T of the homogeneous system can be calculated by the relationship between pressure and distance of the homogeneous system. ω , as shown in formula (3); the viscosity η of the homogeneous system is calculated by shear stress and shear rate α The change relationship is shown in formula (4). The viscosity value reflects the flow resistance of the homogeneous system. The higher the temperature, the lower the viscosity value.

[0056]

[0057]

[0058] Rheological properties mainly determine the quantitative relationship between the viscosity of a homogeneous system and pressure, temperature or shear rate. It characterizes the basic flow properties and is closely related to the appearance, size and structural stability of the final product. By comparing rheological properties with product quality, the optimal combination of process parameters can be obtained.

[0059] In some embodiments, as Figure 1As shown, the video acquisition unit 2 includes: a camera 2-1, which is arranged above the transparent pressing block 1-5 and installed on a universal bracket 2-2, and an optical microscope 2-3 is provided at the bottom of the camera 2-1; a light source 2-4, which is arranged on the side of the camera 2-1 and located above the transparent pressing block 1-5.

[0060] Camera 2-1 is a high-speed camera, which is opposite to the transparent pressing block 1-5 to facilitate dynamic recording of the product foaming process; the optical microscope 2-3 is installed on the camera 2-1, and the bubble image can be magnified through the optical microscope 2-3, so that the camera 2-1 can record the foaming process more clearly.

[0061] The light source 2-4 is set on both sides of the camera 2-1 to provide the camera 2-1 with the lighting conditions required for shooting. The light source 2-4 can be a light pipe, which has high brightness, strong penetration and uniform brightness distribution, allowing the camera 2-1 to shoot under high-quality lighting conditions.

[0062] The camera 2-1 is installed on the universal bracket 2-2. The angle of the camera 2-1 can be adjusted by adjusting the universal bracket 2-2 so that the camera 2-1 can shoot at the optimal angle. The camera 2-1 can also be moved along the molding direction to take pictures to show the complete foaming molding process; the light source 2-4 can be set on the universal bracket 2-2 to adjust the illumination angle of the light source 2-4.

[0063] In some embodiments, as Figure 1 As shown, a pressure valve 1-8 is provided at the outlet of the molding cavity 1-3. When the pressure valve 1-8 is closed, the pressure in the molding cavity 1-3 can be increased to study the effect of pressure on the viscosity of the homogeneous system.

[0064] A limiter 1-7 is provided on the top of the upper die 1-1. The limiter 1-7 can be a rotary buckle for limiting the position of the transparent pressing block 1-5, increasing the downward pressure of the transparent pressing block 1-5, and further improving the strength of the transparent plate 1-4.

[0065] In some embodiments, as Figure 3 As shown, the molding unit 1 also includes: a cooling device 1-6, which is arranged on the top of the upper die 1-1 and / or the bottom of the lower die 1-2; and a heating device 1-9, which is arranged on the side walls of the upper die 1-1 and the lower die 1-2.

[0066] The upper die 1-1, the lower die 1-2 and the sampling plate 3-1 are all made of die steel, which has good heat conduction effect.

[0067] The heating device 1-9 can be a heating wire, which is not limited to a specific one. Figure 3As shown, the number of heating devices 1-9 can be two groups, which are respectively arranged on the opposite side walls of the upper mold 1-1 and the lower mold 1-2 to improve the heating effect. The injection foaming molding process is an intermittent periodic injection. Before injection foaming, the upper mold 1-1 and the lower mold 1-2 can be heated and insulated by the heating device 1-9 to ensure that the molding cavity 1-3 has a suitable molding temperature, and at the same time ensure that the homogeneous system in the capillary channel 3-2 can flow smoothly to prevent the homogeneous system from being blocked due to a sudden drop in temperature.

[0068] The cooling devices 1-6 may be refrigerators, which are not specifically limited. Figure 3 As shown, the number of cooling devices 1-6 can be two groups, which are respectively arranged at the top of the upper mold 1-1 and the bottom of the lower mold 1-2 to improve the cooling effect. The injection foaming molding process is intermittent periodic injection. After the injection foaming starts, after a short period of pressure holding, the upper mold 1-1 and the lower mold 1-2 are cooled by the cooling device 1-6, so that the high-temperature homogeneous system in the molding cavity 1-3 can be initially cooled and formed during the foaming process to avoid large foaming and affecting the product quality. The top of the transparent pressing block 1-5 passes through the cooling device 1-6 set on the top of the upper mold 1-1 to avoid affecting the collection of product image information.

[0069] The heating device 1-9 and the cooling device 1-6 are arranged at different positions of the upper die 1-1 and the lower die 1-2, on the one hand to avoid the temperature control conflict between heating and cooling, and on the other hand to improve the temperature control effect and make the heating and cooling changes in the molding cavity 1-3 uniform.

[0070] In some embodiments, as Figure 4 As shown, the microcellular foam molding visual monitoring device also includes: an injection unit 4, which is connected to the inlet of the molding cavity 1-3; a supercritical fluid generating unit 5, which is connected to the injection unit 4; a molding unit 6, which is connected to the outlet of the molding cavity 1-3, and a traction device 7 is provided at the outlet of the molding unit 6, and a cutting device 8 is provided at the outlet of the traction device 7.

[0071] The supercritical fluid generating unit 5 is used to deliver supercritical fluid to the injection unit 4, and includes a gas cylinder 5-5, a cooling pump and a high-pressure metering pump, wherein the gas cylinder is used to store gas for generating supercritical fluid, and the gas in the gas cylinder 5-5 is cooled and compressed by the cooling pump and then enters the high-pressure metering pump, and is converted into a supercritical fluid after being pressurized by the high-pressure metering pump; the cooling pump can compress the gas output from the gas cylinder 5-5 in advance, thereby improving the pressurization efficiency of the high-pressure metering pump, so that the gas output from the gas cylinder 5-5 is quickly converted into a supercritical fluid; the gas in the gas cylinder 5-5 can be carbon dioxide or nitrogen, which is not specifically limited.

[0072] In some embodiments, as Figure 3and Figure 4 As shown, the gas in the gas cylinder 5-5 is carbon dioxide, the heating device 1-9 is a condenser, and the cooling device 1-6 is an evaporator; the supercritical fluid generating unit 5 is connected to the inlet of the condenser, and a first valve 5-1 is connected between the supercritical fluid generating unit 5 and the condenser; the outlet of the condenser is connected to the inlet of the evaporator, and a throttle valve 5-4 is connected between the condenser and the evaporator; the outlet of the evaporator is connected to the gas cylinder 5-5 of the supercritical fluid generating unit 5, and a vaporization chamber 5-3 and a second valve 5-2 are connected between the evaporator and the supercritical fluid generating unit 5.

[0073] A carbon dioxide transcritical circulation system is formed by the supercritical fluid generating unit 5, the condenser, the throttle valve 5-4 and the evaporator. The supercritical fluid generating unit 5 can generate supercritical carbon dioxide, which enters the condenser for constant pressure heat release, thereby increasing the temperature of the upper mold 1-1 and the lower mold 1-2; the carbon dioxide flows out of the condenser and enters the throttle valve 5-4 for pressure reduction to become wet steam, and the wet steam enters the evaporator for evaporation and heat absorption, thereby decreasing the temperature of the upper mold 1-1 and the lower mold 1-2; the gaseous carbon dioxide flows out of the evaporator and flows back to the supercritical fluid generating unit 5, thereby realizing a cyclic cooling and heating process and improving the energy utilization rate of the supercritical fluid generating unit 5.

[0074] The first valve 5-1 and the second valve 5-2 can be one-way valves, and are not specifically limited. The injection foaming molding process is an intermittent periodic injection. Before injection foaming, the first valve 5-1 can be opened, and the throttle valve 5-4 and the second valve 5-2 can be closed to allow supercritical carbon dioxide to enter the condenser and heat the upper mold 1-1 and the lower mold 1-2; after the injection foaming starts, after a short period of pressure maintenance, the first valve 5-1 is closed and the throttle valve 5-4 is opened to allow carbon dioxide to flow out of the condenser and enter the throttle valve 5-4 for pressure reduction to become wet steam, and then enter the evaporator for evaporation and heat absorption, thereby cooling the upper mold 1-1 and the lower mold 1-2; after the injection foaming is completed, the second valve 5-2 is opened to allow gaseous carbon dioxide to flow out of the evaporator and flow back to the supercritical fluid generating unit 5, completing the cycle process.

[0075] By controlling the three valves, a time difference is formed between the heating process and the cooling process of the upper die 1-1 and the lower die 1-2 to avoid temperature control conflicts. The time control of the heating process and the cooling process can be adjusted according to the foaming process.

[0076] A vaporization chamber 5-3 is connected between the evaporator and the supercritical fluid generating unit 5, which can fully vaporize the carbon dioxide flowing out of the evaporator; the condenser and the evaporator can be heat exchangers, and the heat exchanger consists of a coil and a heat sink. The coil provides space for the carbon dioxide to change its form, and the heat sink can expand the heat exchange area.

[0077] The injection unit 4 is used to fuse the polymer melt and the supercritical fluid to form a homogeneous system, and inject the homogeneous system into the molding cavity 1-3. The injection unit 4 includes a barrel 4-1, a screw and a foaming head, wherein the barrel 4-1 is used to hold polymer particles and heat the polymer particles to a molten state to form a polymer melt; the supercritical fluid enters the barrel 4-1 and fuses with the polymer melt to form a homogeneous system; the foaming head is arranged at the discharge end of the barrel 4-1, and the screw can push the polymer melt / supercritical fluid homogeneous system into the foaming head. The homogeneous system generates a pressure drop through the foaming head, and the internal gas begins to precipitate and nucleate under the drive of the pressure drop.

[0078] The shaping unit 6 is used to cool and shape the polymer melt / supercritical fluid homogeneous system after foaming; the traction device 7 can be a roller traction machine, which can continuously pull the product 10 from the molding cavity 1-3 to the cutting device 8; the cutting device 8 can cut the cooled and shaped product 10 according to a preset length to meet the size requirements of the product 10.

[0079] In some embodiments, as Figure 5 As shown, the shaping unit 6 includes: an upper shaping box 6-1 and a lower shaping box 6-2 that are detachably connected, with a shaping channel 6-3 formed therebetween and running along the shaping direction, a first coolant 6-4 is contained in the upper shaping box 6-1 and the lower shaping box 6-2, and the inlet of the shaping channel 6-3 is connected to the outlet of the shaping cavity 1-3; a cooling box 6-5, which contains a second coolant 6-6, and the side wall of the cooling box 6-5 is provided with a feed port 6-7 and a discharge port 6-8 along the shaping direction, the feed port 6-7 is opposite to the outlet of the shaping channel 6-3, and a sealing member 6-9 is provided on the feed port 6-7 and the discharge port 6-8 respectively.

[0080] The cross-sectional dimensions of the shaping channel 6-3 are the same as those of the final product 10. The homogeneous system after foaming and molding enters the shaping channel 6-3 and is in close contact with the upper shaping box 6-1 and the lower shaping box 6-2 for preliminary cooling and heat exchange with the first cooling liquid 6-4, so that the shape of the product 10 is initially shaped; the preliminarily shaped product 10 enters the cooling box 6-5 from the feed port 6-7 for secondary cooling, and the product 10 is immersed in the second cooling liquid 6-6 for heat exchange, so that the product 10 is finally cooled and shaped; the finally shaped product 10 leaves the cooling box 6-5 from the discharge port 6-8 for rapid cutting, which can ensure the cutting effect and meet the size requirements of the product 10.

[0081] The initial cooling operation adopts contact cooling, which can only cool and shape the surface of the homogeneous system, and the cooling speed is slow, but it ensures the size and shape accuracy of the product 10; the secondary cooling operation adopts immersion cooling, which can cool and shape the interior of the homogeneous system, and the cooling speed is fast; the two-stage cooling and shaping operation further improves the cooling speed of the product 10, and also improves the shaping effect, thereby ensuring the cutting quality of the subsequent product 10.

[0082] The first coolant 6-4 can be cooling oil to improve the cooling effect; the second coolant 6-6 can be cooling water, which will not contaminate the product 10. After the product 10 is finally shaped, the cooling water attached can evaporate naturally and will not affect the quality of the product 10; the feed port 6-7 and the outlet of the shaping channel 6-3 are relative to each other, which can prevent the product 10 from bending and deforming; the sealing member 6-9 is, for example, a rubber ring, which is not specifically limited. The sealing member 6-9 can reduce the leakage of the second coolant 6-6 from the feed port 6-7 and the discharge port 6-8, thereby ensuring the sealing of the cooling box 6-5.

[0083] In some embodiments, as Figure 4 As shown, the injection unit 4 includes: a barrel 4-1, and a second pressure sensor 4-2 is provided on the side wall.

[0084] The second pressure sensor 4 - 2 is used to measure the hydrostatic pressure parameter of the polymer melt and can perform pressure calibration on the first pressure sensor.

[0085] In some embodiments, as Figure 4 and Figure 6 As shown, the microcellular foam molding visual monitoring device also includes: a computer terminal 9, which is electrically connected to the injection unit 4, the supercritical fluid generating unit 5, the molding unit 1, the shaping unit 6, the video acquisition unit 2 and the testing unit 3.

[0086] The computer terminal 9 is electrically connected to the injection unit 4, and can control the start or stop rotation of the screw and control the rotation speed, can control the temperature and pressure of the fusion of the polymer melt and the supercritical fluid, can control the bubble nucleation efficiency of the foaming head; can control the flow rate of the polymer melt / supercritical fluid homogeneous system entering the molding unit 1; can collect the hydrostatic pressure parameters of the polymer melt.

[0087] The computer terminal 9 is electrically connected to the supercritical fluid generating unit 5, and can control the conversion of gas into supercritical fluid, and control the filling amount of supercritical fluid injected into the injection unit 4, and can control the supercritical fluid to enter the condenser and control the gas flowing out of the storage evaporator.

[0088] The computer terminal 9 is electrically connected to the molding unit 1 , and can control the temperature and pressure of the polymer melt / supercritical fluid homogeneous system during the foaming molding process, and can control the homogeneous system after foaming molding to enter the shaping unit 6 .

[0089] The computer terminal 9 is electrically connected to the camera acquisition unit 2, and can collect product image information of the polymer melt / supercritical fluid homogeneous system during the foaming molding process, analyze the surface roughness, smoothness, whether there are bubbles, flow marks, floating fibers and other surface quality problems of the product surface, and compare and analyze with pre-set qualified product pictures to determine whether there are problems with the surface quality of the product under such process conditions and put forward corresponding adjustment suggestions.

[0090] The computer terminal 9 is electrically connected to the test unit 3, and can collect the temperature and pressure changes of the polymer melt / supercritical fluid homogeneous system during the foaming molding process, and then analyze the rheological properties of the homogeneous system. By comparing with the product image information at the corresponding position, the process parameters can be improved to obtain the optimal process parameter combination; the relationship between the process parameters, the rheological properties of the homogeneous system and the bubble morphology in the microporous foaming molding process can be explored, and the foaming behavior of the homogeneous system can be analyzed and predicted.

[0091] The computer terminal 9 is electrically connected to the shaping unit 6 , and can control the speed and effect of cooling and shaping the foam-molded product 10 ; and control the size of the final product 10 .

[0092] The various embodiments in this application are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0093] The description of this application is provided for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the disclosed form. Many modifications and variations will be apparent to those skilled in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of this application and to enable those skilled in the art to understand the application and design various embodiments with various modifications suitable for specific applications.

[0094] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present application (including the claims) is limited to these examples. Within the scope of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0095] In addition, when details are set forth to describe exemplary embodiments of the present application, it will be apparent to those skilled in the art that the present application embodiments can be implemented without these details or with variations in these details. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0096] While the present application has been described in conjunction with the embodiments thereof, many alternatives, modifications and variations of these embodiments will be apparent to those skilled in the art in light of the foregoing description.

[0097] The embodiments of the present application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the scope of protection of this application.

Claims

1. A visual monitoring device for microcellular foaming, characterized in that: include: A molding unit comprises a detachably connected upper die and a lower die, wherein a through molding cavity is formed between the upper die and the lower die along a molding direction, a transparent plate is provided at the top of the molding cavity along the molding direction, the transparent plate is fixed to the bottom of the upper die, a transparent pressing block provided along the molding direction abuts against the transparent plate above, and the top of the transparent pressing block passes through the upper die; a camera acquisition unit, disposed above the transparent pressing block and configured to acquire product image information in the molding cavity through the transparent pressing block and the transparent plate; The video acquisition unit includes: a camera, which is arranged above the transparent pressing block and mounted on a universal bracket, and an optical microscope is provided at the bottom of the camera; A light source is provided on the side of the camera and above the transparent pressing block; The testing unit includes a sampling plate, which is arranged at the bottom of the molding cavity along the molding direction and fixed on the top of the lower die. A through capillary channel is provided inside the sampling plate along the molding direction. Both ends of the capillary channel are connected to the interior of the molding cavity. Test sensors are provided at intervals at the bottom of the capillary channel along the molding direction.

2. The visual monitoring device for microcellular foaming molding according to claim 1, characterized in that: The test sensor includes a first pressure sensor and a temperature sensor.

3. The visual monitoring device for microcellular foaming molding according to claim 1, characterized in that: A pressure valve is provided at the outlet of the molding cavity, and a limiting piece is provided at the top of the upper die.

4. The visual monitoring device for microcellular foaming molding according to claim 1, characterized in that: Also includes: an injection unit, connected to the inlet of the molding cavity; a supercritical fluid generating unit, connected to the injection unit; The shaping unit is communicated with the outlet of the shaping cavity. A traction device is provided at the outlet of the shaping unit, and a cutting device is provided at the outlet of the traction device.

5. The visual monitoring device for microcellular foaming molding according to claim 4, characterized in that: The molding unit further comprises: A cooling device is provided on the top of the upper die and / or the bottom of the lower die; A heating device is arranged on the side walls of the upper die and the lower die.

6. The visual monitoring device for microcellular foaming molding according to claim 5, characterized in that: The temperature-raising device is a condenser, the temperature-lowering device is an evaporator, the supercritical fluid generating unit is connected to the inlet of the condenser, the outlet of the condenser is connected to the inlet of the evaporator, a throttle valve is connected between the condenser and the evaporator, and the outlet of the evaporator is connected to the gas storage bottle of the supercritical fluid generating unit.

7. The visual monitoring device for microcellular foaming molding according to claim 4, characterized in that: The shaping unit comprises: An upper molding box and a lower molding box are detachably connected, with a molding channel formed therebetween and extending along the molding direction. A first coolant is contained in the upper molding box and the lower molding box, and an inlet of the molding channel is connected to an outlet of the molding cavity. A cooling box is provided with a second coolant inside, and a side wall of the cooling box is provided with a feed port and a discharge port along the forming direction, the feed port and the outlet of the shaping channel are opposite to each other, and a sealing member is provided on the feed port and the discharge port respectively.

8. The visual monitoring device for microcellular foaming molding according to claim 4, characterized in that: The injection unit includes a barrel, and a second pressure sensor is provided on a side wall of the barrel.

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