Preparation system and preparation method of structural adhesive test sample for automobile

Abstract

The invention discloses a preparation system and a preparation method of a structural adhesive test sample for an automobile. The preparation system comprises a forming mold; a temperature control assembly; a glue gun assembly; a pressure maintaining assembly; provided is a program control device. Through the design of the middle-layer mold and the silicon-plated film in the forming mold, the demolding performance of the structural adhesive test sample is improved; through the design of the temperature control assembly, the glue gun assembly, the pressure maintaining assembly and the program controller, stable glue injection and curing are achieved, the prepared structural glue test sample is good in surface quality and free of internal defects, and the forming quality and the yield of the structural glue test sample are improved; and the obtained structural adhesive test sample has good and stable mechanical properties.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile manufacturing, and particularly to a preparation system and a preparation method for a structural adhesive test sample for an automobile, which are designed for the preparation method and a special device of a structural adhesive dumbbell sample in the steel-aluminum hybrid body connection technology, and are particularly suitable for the high-precision forming and rapid demolding of high-viscosity structural adhesives. Background Art

[0002] The steel-aluminum hybrid body technology is an important development technology in the field of automobile manufacturing in recent years. Due to its high strength and light weight, the steel-aluminum hybrid body has attracted much attention under the increasing demand for automobile lightweighting.

[0003] At present, the connection technologies for steel-aluminum hybrid bodies mainly include riveting, welding (laser welding, spot welding, etc.), bonding, and mechanical connection, etc., each having its own advantages and disadvantages. Among them, bonding can connect various materials, has a simple process, does not require pre-drilled holes, can reduce weight and cost, has a uniform stress distribution in the adhesive layer, has good performance in terms of sealing, shock absorption, durability, and fatigue resistance, can connect complex structures, and has a protective effect on electrochemical corrosion. The adhesive-riveting combined connection technology combines the advantages of advanced riveting technologies such as self-piercing riveting and flow drill riveting with bonding to form a new type of connection method. Compared with traditional pure riveted joints, the adhesive-riveting composite joints have significantly improved strength, stiffness, and fatigue performance. In this composite connection, the contribution of the adhesive to the mechanical properties of the joint is particularly prominent, and the combined action of factors such as its curing temperature, curing time, and adhesive layer thickness has a significant impact on the joint performance. Therefore, it is particularly important to deeply study the performance of structural adhesives, which helps to better understand and optimize the mechanical behavior of adhesive-riveting composite joints, improve the strength of new connection processes, significantly enhance the safety performance of the whole vehicle, identify and solve potential performance bottlenecks, and ensure the reliability and durability of adhesive-riveting combined connections in practical applications. This comprehensive research method is of great significance for promoting technological progress in the field of automobile manufacturing.

[0004] The existing structural adhesive test samples have the following disadvantages during the preparation process and are difficult to meet the high-precision test requirements: 1. Difficult demolding: Since the structural adhesive body is in a high-viscosity fluid state and forms a solid with a relatively high hardness after heat curing treatment, reprocessing is likely to cause defects on the surface of the sample or even cause the sample to break. Moreover, during the curing process, a very strong adhesion force will be generated at the edge of the structural adhesive, and the cured colloid will adhere to the metal mold, and demolding is likely to cause damage to the sample. 2. Unstable extrusion of the colloid: Due to the relatively high viscosity of the colloid, it is difficult to stably extrude it by manpower alone, resulting in low extrusion efficiency and many bubbles. 3. Uncontrollable curing pressure: The thermal expansion of the colloid causes internal defects, affecting the quality of the test sample. Summary of the Invention

[0005] The present invention provides a preparation system and a preparation method for an automotive structural adhesive test sample, which can solve the above-mentioned defects existing in the preparation process of automotive structural adhesive test samples in the prior art.

[0006] To solve the above technical problems, the present invention provides a preparation system for an automotive structural adhesive test sample, comprising: A molding die, which includes an upper die, a middle die, and a lower die; wherein, the middle die is provided with a colloid molding cavity and a glue injection port and an overflow port communicating therewith; the middle die is a die made of Teflon material, and silicon-coated films are laid on both sides thereof; A temperature control component, which is installed in a groove at the bottom of the lower die; A glue gun component, which is detachably connected to the glue injection port and is used for injecting structural adhesive into the colloid molding cavity; A pressure maintaining component, which is detachably connected to the glue injection port and the overflow port and is used for stabilizing the pressure in the molding die during the glue injection process and the curing process; A program control device, which is signal-connected to the temperature control component, the glue gun component, and the pressure maintaining component.

[0007] In a preferred embodiment of the present invention, dovetail lifting plates are further provided on the upper die and the middle die.

[0008] In a preferred embodiment of the present invention, the glue injection port and the overflow port are located at both ends of the colloid molding cavity, and the overflow port is connected to a vertical threaded port penetrating through the upper die.

[0009] In a preferred embodiment of the present invention, the temperature control component includes a thermocouple, an electric heating pipeline, and a cooling water channel; wherein, the thermocouple and the switching valves of the electric heating pipeline and the cooling water channel are respectively signal-connected to the program control device.

[0010] In a preferred embodiment of the present invention, the glue gun component includes a glue gun body, a pressing plate, and a speed regulating motor; wherein, the glue outlet end of the glue gun body is threadedly connected to the glue injection port, the pressing plate is installed at the other end thereof, and the speed regulating motor is connected to the pressing plate to drive the pressing plate to extrude glue towards the glue outlet end; the speed regulating motor is signal-connected to the program control device.

[0011] In a preferred embodiment of the present invention, a preheating coil is further wound around the glue gun body for preheating the colloid in the glue gun body.

[0012] In a preferred embodiment of the present invention, the pressure-holding assembly includes a pressure-controlled overflow tank, and the open end of the pressure-controlled overflow tank is connected to the glue injection port or the overflow port; a pressure-regulating piston, a pressure-regulating spring and a pressure-regulating screw are sequentially installed in the pressure-controlled overflow tank from the open end to the other end; the pressure-regulating screw penetrates through the pressure-controlled overflow tank and is connected to a pressure calculator, and the pressure calculator is in signal connection with the program control device.

[0013] In a preferred embodiment of the present invention, a protection air hole is further opened on one side of the pressure-controlled overflow tank, and the protection air hole is located below the pressure-regulating screw when the pressure-controlled overflow tank is in the maximum pressure state.

[0014] To solve the above technical problems, the present invention also provides a preparation method for a structural adhesive test sample for an automobile, which uses the above preparation system and includes the following steps: (1) Mold preheating: Turn on the temperature control component to preheat the forming mold to 40-60 °C; (2) Glue injection: Install the pressure-holding assembly and the glue gun assembly on the overflow port and the glue injection port respectively. The program control device adjusts the glue extrusion speed of the glue gun assembly through the PID algorithm according to the real-time pressure data fed back by the pressure calculator of the pressure-holding assembly, and extrudes glue into the forming mold; (3) Heating and curing forming: Remove the glue gun assembly, install the pressure-holding assembly on the glue injection port, adjust the upper limit values of the pressures of the two pressure-holding assemblies, and complete the heating and curing treatment through the temperature control component; (4) Cooling and demolding: After curing, cool with the mold to below 50 °C, open the mold and demold to obtain the structural adhesive test sample for the automobile.

[0015] In a preferred embodiment of the present invention, in step (3), the temperature control component monitors the temperature of the forming mold in real time, and dynamically adjusts the heating power through the PID controller in the temperature control component by using the PID algorithm.

[0016] The beneficial effects of the present invention are as follows: For the preparation system of the structural adhesive test sample for an automobile of the present invention, through the design of the middle mold and the silicon-coated film in the forming mold, the demolding performance of the structural adhesive test sample is improved; through the design of the temperature control component, the glue gun assembly, the pressure-holding assembly and the program controller, stable glue injection and curing are realized, so that the surface quality of the prepared structural adhesive test sample is good, there are no internal defects, the forming quality and the yield of the structural adhesive test sample are improved; the mechanical properties of the obtained structural adhesive test sample are good and stable. Description of the Drawings

[0017] Figure 1 It is a three-dimensional structural schematic diagram of the forming mold in the preparation system of the structural adhesive test sample for an automobile of the present invention Figure 1 ; Figure 2 Schematic three-dimensional structure of the molding die in the preparation system of a structural adhesive test sample for an automobile according to the present invention Figure 2 ; Figure 3 Exploded structure schematic diagram of the shown molding die; Figure 4 Schematic structure diagram of the shown middle-layer die; Figure 5 Combined structure schematic diagram of the shown molding die, temperature control component and program control device; Figure 6 Temperature feedback regulation control flow chart of the shown molding die; Figure 7 Combined structure schematic diagram of the shown molding die and glue gun assembly; Figure 8 Pressure holding feedback regulation control schematic diagram of the shown glue gun assembly; Figure 9 Combined structure schematic diagram of the shown molding die and pressure holding component; Figure 10 Internal structure schematic diagram of the shown pressure control overflow tank; Figure 11 Schematic diagram of the tensile test results of the test sample prepared in Example 2; The markings of each component in the drawings are as follows: 10. Molding die, 11. Upper-layer die, 12. Middle-layer die, 13. Lower-layer die, 14. U-shaped bolt groove, 15. Dovetail lifting plate, 16. Silicon-coated film, 121. Colloid molding cavity, 122. Glue injection port, 123. Overflow port, 124. Positioning pile, 125. Vertical threaded port, 131. Die positioning anchor hole, 132. Nut limit groove, 133. Temperature control component installation groove; 20. Temperature control component, 21. Thermocouple, 22. Electric heating pipe, 23. Cooling water channel, 30. Glue gun assembly, 31. Glue gun body, 32. Pressure plate, 33. Speed regulating motor, 34. Preheating coil, 40. Pressure control overflow tank, 41. Pressure regulating piston, 42. Pressure regulating spring, 43. Pressure regulating screw, 44. Protection air hole, 45. Pressure calculator; 50. Program control device. Detailed implementation manners

[0018] The following elaborates on the preferred embodiments of the present invention in conjunction with the drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making the protection scope of the present invention more clearly defined.

[0019] Example 1

[0020] The present invention discloses a preparation system for a structural adhesive test sample for an automobile, including a forming mold 10, a temperature control component 20, a glue gun component 30, a pressure maintaining component, and a program control device 50.

[0021] As Figures 1-4 shown, the forming mold 10 includes an upper mold 11, a middle mold 12, and a lower mold 13. Both the upper mold 11 and the lower mold 13 are made of high-strength mold steel to ensure the overall stiffness and stability of the forming mold. The middle mold 12 is made of Teflon material, which does not adhere to the cured structural adhesive, so as to facilitate the demolding of the formed structural adhesive test sample and improve the forming quality.

[0022] Specifically, a total of 8 U-shaped bolt slots 14 are provided at the two side edges of the forming mold 10 for positioning fastening bolts, improving the convenience and accuracy of installing the forming mold on the machine tool.

[0023] Four precise mold positioning anchor holes 131 are designed at the edge of the lower mold 13 for the precise positioning and installation of the forming mold 10. The bottom of the lower mold 13 also has a nut limiting groove 132 and a temperature control component installation groove 133. Through the structural design of the lower mold 13, the overall rapid and accurate positioning and installation of the forming mold are realized.

[0024] Dovetail lifting plates 15 are installed on both the upper mold 11 and the middle mold 12, facilitating the quick opening of the middle mold 12 from the forming mold, realizing the quick disassembly, assembly, and sampling of the forming mold.

[0025] The middle mold 12 is provided with a colloid forming cavity 121, specifically a standard dumbbell-shaped forming cavity in ASTM D638 standard. One end of the colloid forming cavity 121, such as Figure 4 the right end shown, is an open end and is connected to a horizontal glue injection port 122, which is a horizontal threaded port. The other end of the colloid forming cavity 121, that is, Figure 4 the left end in, is a closed end with an overflow port 123. The overflow port 123 is connected to a vertical threaded port 125 arranged vertically, and the vertical threaded port 125 penetrates through the upper mold 11 upward. The overflow port 123 is used to adjust the pressure and exhaust air in the colloid forming cavity 121, ensuring the unidirectional movement of the colloid to fill the cavity, so as to ensure the integrity and forming quality of the forming. In addition, 4 positioning posts 124 arranged at intervals are provided in the area where the center line of the middle mold 12 is located, and corresponding positioning grooves are provided on the upper mold 11. Specifically, the positioning posts 124 are cylindrical with a diameter of 5 mm and are in clearance fit with the positioning grooves of the upper mold 11, used to determine the position of the middle mold 12 and ensure the precise alignment of the molds.

[0026] In addition, a layer of 0.1-0.3 mm thick silicon-coated film 16 made of polysiloxane composite material is laid on both sides of the middle mold 12 and between the upper mold 11 and the lower mold 13. The silicon-coated film has strong polymer repellency and will not produce adhesion with the cured structural adhesive. At the same time, the silicon-coated film is thin, strong, and has good density, and is a good material for the interlayer of the structural adhesive molding mold.

[0027] The material design of the middle mold 12 and the use of the silicon-coated films 16 on both sides thereof can effectively prevent the structural adhesive from adhering to the mold after molding, making demolding easier, thereby improving the demolding effect and preventing adhesion to the metal mold to affect the quality of the test sample after molding and the accuracy of the test results.

[0028] like Figure 5 As shown, the temperature control component 20 is installed in a groove at the bottom of the lower mold 13, specifically in a temperature control component installation groove 133. The temperature control component 20 includes a thermocouple 21, an electric heating pipe 22 and a cooling water channel 23.

[0029] The electric heating pipe 22 and the cooling water channel 23 are arranged in a rectangular shape, and the cooling water channel 23 is located inside the electric heating pipe 22. The thermocouple 21 is installed on the lower mold and symmetrically distributed outside the electric heating pipe 22 to monitor the temperature of the molding mold in real time. The thermocouple 21 and the switch valves of the electric heating pipe 22 and the cooling water channel 23 are respectively connected to the program control device 50 by signal.

[0030] The program control device 50 contains a small computer, which can set the temperature required for curing and control the electric heating pipe current and the opening and closing of the water flow in the cooling water channel 23. The program control device 50 also has a PID regulator, which can achieve precise control of electric heating and water cooling based on the temperature signal fed back by the thermocouple 21 in real time through the PID algorithm to achieve the purpose of constant temperature control. The specific temperature feedback control flow chart is shown in the attached figure. Figure 6 shown.

[0031] like Figure 7As shown, the glue gun assembly 30 is detachably connected to the glue injection port 122 and is used to inject structural glue into the colloidal molding cavity 121. Specifically, the glue gun assembly 30 includes a glue gun body 31, a pressing plate 32, a speed-regulating motor 33, and a preheating coil 34. Among them, the glue outlet end of the glue gun body 31 (i.e., the glue gun nozzle) is threadedly connected to the glue injection port 122, and the pressing plate 32 is installed at the other end thereof. The speed-regulating motor 33 is connected to the pressing plate 32 to drive the pressing plate 32 to extrude glue toward the glue outlet end, so as to ensure that the glue gun body 31 extrudes the structural glue into the molding die at a stable speed. The preheating coil 34 is wound around the glue gun body 31 and preheats and softens the structural glue therein to reduce the viscosity of the colloid and increase the fluidity of the colloid. The speed-regulating motor 33 is signal-connected to the program control device 50, and the program control device 50 can regulate the speed of the speed-regulating motor 33 to adjust the glue injection speed.

[0032] The pressure maintaining assembly is detachably connected to the glue injection port 122 and the vertical thread port 125 and is used to stabilize the pressure in the molding die during the glue injection process and the curing process.

[0033] The pressure maintaining assembly is a pressure control overflow tank 40, and the open end of the pressure control overflow tank 40 is threadedly connected to the glue injection port 122 or the vertical thread port. As Figure 10 shown, a pressure regulating piston 41, a pressure regulating spring 42, and a pressure regulating screw 43 are sequentially installed in the pressure control overflow tank 40 from the open end to the other end. The pressure regulating spring 42 is located between the pressure regulating piston 41 and the pressure regulating screw 43, and the pressure regulating screw 43 penetrates through the pressure control overflow tank 40. The pressure regulating screw 43 is also connected to a pressure calculator 45, which can calculate the pressure in the pressure control overflow tank 40 according to the telescopic beam of the pressure regulating screw and is used to monitor the pressure in the colloidal molding cavity 121 in real time.

[0034] The pressure calculator 45 is signal-connected to the program control device 50. The program control device 50 can preset the pressure in the pressure control overflow tank 40. The pressure regulating screw 43 can rotate. By rotating the pressure regulating screw 43, the tension of the pressure regulating spring 42 can be adjusted to reach the set pressure value, and the accuracy is high.

[0035] A protection air hole 44 is further opened on one side of the pressure control overflow tank 40, and the protection air hole 44 is located below the pressure regulating screw 43 when the pressure control overflow tank is in the maximum pressure state. When the internal pressure of the pressure maintaining overflow tank is higher than the set pressure, the pressure regulating piston 41 is extruded to a position higher than the protection air hole 44. At this time, the protection air hole 44 is communicated with the outside, and the gas is preferentially discharged to avoid the overload failure of the pressure regulating spring and improve the safety of the system. This setting can accurately control the pressure in the molding die, ensure the stability and safety of the pressure during the glue injection or curing process, and thus improve the molding quality of the test sample.

[0036] The protection air hole is located below the pressure regulating screw. Specifically, during the glue injection process, the overflow port 123 is threadedly connected to the pressure control overflow tank 40, the glue injection port 122 is connected to the glue gun body in the glue gun assembly 30, and the speed regulating motor 33 is connected to the program control device. The pressure calculator 45 provides real-time feedback on the pressure in the cavity of the colloid forming die to the program control device 50. The program control device 50 adjusts the speed of the speed regulating motor 33 through a PID controller, thereby realizing the adjustment of the glue injection speed according to the real-time pressure in the cavity of the colloid forming die, effectively reducing the problem of gas existing inside the test sample, and significantly improving the finished product quality of the structural adhesive test sample. The glue injection speed adjustment diagram is as Figure 8 shown.

[0037] As Figure 9 shown, during the curing and forming process, the glue injection port 122 is threadedly connected to another pressure control overflow tank 40. During the curing process, the internal control of the forming mold expands due to heat, accumulates inside the pressure control overflow tank 40 and presses the pressure regulating piston 41. The displacement of the pressure regulating piston 41 is limited by the tension force of the pressure regulating spring 42, thereby achieving the effect of controlling the internal pressure of the mold. When the internal pressure of the pressure control overflow tank 40 is higher than the set pressure, the position of the pressure regulating piston 41 being pressed is higher than the protection position. At this time, the protection air hole 44 leaks to connect to the outside, discharging excess air for pressure adjustment. This system ensures the stability of the mold during the curing process by precisely controlling the pressure inside the mold, thereby improving the quality of the sample.

[0038] Example 2

[0039] Taking the 1840C one-component epoxy-based adhesive widely used in the current automotive manufacturing industry as an example, the preparation process of its test sample is described.

[0040] 1. Working environment preparation and material pretreatment First, thoroughly purify the working environment to ensure it meets the standards of being sterile and dust-free. Cut two precisely measured silicon-coated films, and turn on the preheating coil 34 in the glue gun assembly 30 for preheating treatment to improve the fluidity of the colloid and reduce adhesion.

[0041] 2. Assembly and debugging of the mold system 2.1 Mold positioning and fixation Through the precise mold positioning anchor holes 131, firmly fix the lower mold 13 on the workbench using high-strength bolts to ensure its stability and accuracy during operation.

[0042] 2.2 Installation of hot and cold runners and thermocouples Precisely install the hot and cold runners 23 and the thermocouple 21 in the temperature control component installation groove 133 of the lower mold 13 to ensure its tight combination with the lower mold 13 and provide accurate data support for subsequent temperature control.

[0043] 2.3 Laying of silicon-coated film Lay a layer of processed silicon-coated film 16 with a thickness of 0.2 mm on the lower mold 13 to reduce the adhesion between the mold and the colloid and improve the demolding efficiency.

[0044] 2.4 Assembly of the middle mold Install the middle mold 12 on the lower mold 13 and the silicon-coated film 16 thereon through precise positioning holes, and install the glue gun adapter to ensure the integrity and functionality of the mold structure.

[0045] 2.5 Laying of the top film Lay another layer of silicon-coated film 16 on the middle mold 12 to further improve the demolding effect and the sealing performance of the mold.

[0046] 2.6 Installation of the overflow adapter and the upper mold Install the vertical threaded port, that is, the overflow port 123 and the upper mold 11 on the middle mold 12 and the silicon-coated film 16 thereon to ensure the sealing and functionality of the mold system.

[0047] 2.7 Tightening and inspection of the whole mold Use high-strength tightening bolts to tighten the whole forming mold, and ensure through a precise inspection mechanism that there is no looseness or displacement of the mold body to ensure the stability and accuracy of the mold.

[0048] 3. Colloid injection and curing process 3.1 Preheat the mold Turn on the temperature control component 20, set the preheating temperature to 50°C ± 5°C, the heating-up time to 5 min, and keep it warm before curing. This temperature can reduce the viscosity of the 1840C one-component epoxy-based adhesive, make the colloid have good fluidity, and enable it to fully conform to the inner surface of the mold.

[0049] 3.2 Connect the glue gun assembly Threadedly install the pressure-controlled overflow tank 40 on the overflow port 123, threadedly connect the glue gun system to the glue injection port 122, and at the same time input the real-time pressure of the pressure-controlled overflow tank 40 into the program control device 50. According to the actual sample size, adjust the pressure-regulating screw 43 of the pressure-controlled overflow tank 40 so that the upper limit of the pressure that the pressure-controlled overflow tank 40 can withstand is 0.3 MPa. Set the glue extrusion speed to be between 0.8 ml / s and 1 ml / s, and evenly and stably extrude the structural glue into the molding die. The total extrusion amount is 11 ml. According to the real-time pressure data of the pressure calculator 45 at the overflow port 123, the rotation speed of the speed-regulating motor 33 in the glue gun assembly can be closed-loop controlled to control the glue inflow speed and keep the pressure in the overall die at about 0.25 MPa. Keeping the pressure in the die can increase the density of the glue sample, effectively reduce the internal bubble defects of the molded glue sample, and ensure the accuracy and yield of the test sample.

[0050] 3.3 Installation of the pressure-controlled overflow tank at the glue injection port After the glue injection is completed, remove the glue gun assembly 30 and horizontally install the pressure-controlled overflow tank 40 on the glue injection port. Adjust the upper limit values of the pressures of the two pressure-controlled overflow tanks on the overflow port 123 and the glue injection port 122 to 0.5 MPa respectively to ensure the pressure control during the curing process, avoid the defect problems caused by the thermal expansion of the colloid inside the sample, and improve the quality of the sample.

[0051] 3.4 Setting and execution of the curing parameters In the program control device 50, according to the process manual of the 1840C one-component epoxy-based adhesive, set the curing temperature to 180 °C, the heating-up time to 5 min, and the curing time to 30 min, and start the curing program. At this time, the molding die will gradually heat up to the set temperature and maintain at 180 °C to ensure that the physical properties of the colloid reach the expected standard.

[0052] 3.5 Cooling and disassembly After reaching the curing time of 30 min, the curing is completed. Control the flow of the cooling water through the PID controller (PID algorithm) in the program control device 50 to cool the molding die to 50 °C and keep it warm. At this temperature, it is beneficial for the demolding of the 1840C one-component epoxy-based adhesive dumbbell sample after molding. After the curing is completed, the mold fastening bolts and the pressure-controlled overflow tank can be disassembled to ensure the integrity and safety of the sample.

[0053] 4. Sample removal and quality inspection With the help of the designed dovetail lifting plate 15, carefully and slowly remove the upper mold 11 one by one, and take out the middle mold 12. At this time, the middle mold 12 and the formed specimen are protected by the silicon-coated films 16 on both sides. Uncover the silicon-coated films on both sides. At the same time, since the structural adhesive does not adhere to the Teflon material used for the middle mold 12, the cured dumbbell-shaped specimen can be easily taken out and placed in a safe position and left standing for a period of time to eliminate the residual heat of the specimen, obtaining a dumbbell-shaped test specimen.

[0054] The dumbbell-shaped test specimen prepared by this method is easy to demold, does not stick to the mold, has good surface quality, no bubbles, no sticking mold damage, and no internal defects, and the quality is uniform and stable.

[0055] 10 groups of test specimens were prepared in parallel by the above method and subjected to tensile property tests. The Young's modulus of the 1840C one-component epoxy-based adhesive structural adhesive test specimens was 2505 MPa, and the official data was 2270 MPa; the fracture stress was 35.1 MPa, and the official data was 36 MPa. The standard deviation of the Young's modulus of the 10 groups of test specimens was ±15 MPa, and the standard deviation of the fracture stress was ±0.3 MPa. The consistency was good, indicating that the method and equipment of the present invention have feasibility and reusability, filling the gap in the existing technology. The test results are as shown Figure 11 as follows.

[0056] The present invention has the following advantages: 1. Through the dumbbell-shaped cavity design of the middle mold and the design of the overflow port, the flow direction of the colloid is fixed, and the rapid one-piece forming preparation of the dumbbell-shaped glue sample can be realized.

[0057] 2. The middle mold is made of Teflon material, and the upper and lower molds are designed to be made of mold steel material. During use, silicon-coated films are used to solve the demolding problem after the colloid is cured.

[0058] 3. Through the design of the temperature control component, the integrated production of dumbbell-shaped glue sample forming + curing is realized, ensuring the temperature and time during the curing process, avoiding the problem of insufficient curing caused by unstable furnace temperature, and improving the yield of the glue sample.

[0059] 4. Through the design of the glue extrusion device, preheating of the colloid before extrusion is realized, enhancing the fluidity of the colloid, and then improving the integrity of the colloid filling the mold; through the design of the extrusion motor to ensure the extrusion flow rate, and then reducing the generation of bubbles and improving the quality of the glue sample.

[0060] 5. Through the design of the pressure control overflow tank, the cavity pressure during the curing process of the colloid is ensured, and then the generation of internal bubbles in the colloid caused by volume expansion during the curing process is avoided.

[0061] The above are only embodiments of the present invention, and thus do not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall similarly be included within the patent protection scope of the present invention.

Claims

1. A preparation system for a structural adhesive test sample for an automobile, characterized in that, Including: A forming mold, which includes an upper mold, a middle mold, and a lower mold; wherein, the middle mold is provided with a colloid forming cavity, a glue injection port, and an overflow port communicating therewith; the middle mold is a Teflon material mold, and silicon-coated films are laid on both sides thereof; A temperature control component, which is installed in a groove at the bottom of the lower mold; A glue gun component, which is detachably connected to the glue injection port and is used to inject structural glue into the colloid forming cavity; A pressure maintaining component, which is detachably connected to the glue injection port and the overflow port and is used to stabilize the pressure in the forming mold during the glue injection process and the curing process; A program control device, which is signal-connected to the temperature control component, the glue gun component, and the pressure maintaining component.

2. The preparation system according to claim 1, characterized in that, The upper mold and the middle mold are also provided with dovetail lifting plates.

3. The preparation system according to claim 1, characterized in that, The glue injection port and the overflow port are located at both ends of the colloid forming cavity, and the overflow port is connected to a vertical threaded port penetrating the upper mold.

4. The preparation system according to claim 1, wherein The temperature control component includes a thermocouple, an electric heating pipeline, and a cooling water channel; wherein, the thermocouple and the switching valves of the electric heating pipeline and the cooling water channel are respectively signal-connected to the program control device.

5. The preparation system according to claim 1, characterized in that, The glue gun component includes a glue gun body, a pressing plate, and a speed regulating motor; wherein, the glue outlet end of the glue gun body is threadedly connected to the glue injection port, the pressing plate is installed at the other end thereof, and the speed regulating motor is connected to the pressing plate to drive the pressing plate to extrude glue towards the glue outlet end; the speed regulating motor is signal-connected to the program control device.

6. The preparation system according to claim 5, characterized in that, A preheating coil is also wound around the glue gun body for preheating the colloid in the glue gun body.

7. The preparation system according to claim 1, wherein The pressure maintaining component includes a pressure control overflow tank, and the open end of the pressure control overflow tank is connected to the glue injection port or the overflow port; a pressure regulating piston, a pressure regulating spring, and a pressure regulating screw are sequentially installed in the pressure control overflow tank from the open end to the other end; the pressure regulating screw penetrates through the pressure control overflow tank and is connected to a pressure calculator, and the pressure calculator is signal-connected to the program control device.

8. The preparation system according to claim 7, characterized in that, A protection air hole is also opened on one side of the pressure control overflow tank, and the protection air hole is located below the pressure regulating screw when the pressure control overflow tank is in the maximum pressure state.

9. A preparation method for a structural adhesive test sample for an automobile, characterized in that, Using the preparation system according to any one of claims 1-8, the following steps are included: (1) Mold preheating: Turn on the temperature control component to preheat the forming mold to 40-60 °C; (2) Glue injection: Install the pressure maintaining component and the glue gun component on the overflow port and the glue injection port respectively. The program control device adjusts the glue extrusion speed of the glue gun component through the PID algorithm according to the real-time pressure data fed back by the pressure calculator of the pressure maintaining component, and extrudes glue into the forming mold; (3) Heating and curing forming: Disassemble the glue gun component, install the pressure maintaining component on the glue injection port, adjust the upper limit values of the pressures of the two groups of pressure maintaining components, and complete the heating and curing treatment through the temperature control component; (4) Cooling and demolding: After curing, cool the mold to below 50 °C, open the mold to demold, and obtain the test sample of the automotive structural glue.

10. The preparation method according to claim 9, characterized in that, In step (3), the temperature control component monitors the temperature of the molding die in real time, and the PID controller in the temperature control component dynamically adjusts the heating power by using the PID algorithm.

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