A device and process for injection molding of plastic parts for vehicles with uniform material function

Abstract

This invention discloses an injection molding device and process for automotive plastic parts with a material homogenization function, relating to the field of mold forming technology. It includes a mounting base, a compaction unit, a flash removal unit, a demolding unit, a material homogenization and conveying unit, and a mixing and reaction unit. The mounting base provides a foundation for installation and fixation. The compaction unit is used for mold forming, ensuring complete mold filling and avoiding shrinkage marks that could affect molding quality. The flash removal unit removes flash from the mold after it appears, preventing impact on mold quality and reducing the need for subsequent trimming processes. The demolding unit enables rapid demolding of the mold, ensuring non-destructive demolding and maintaining quality. The material homogenization and conveying unit uniformly mixes monomers and chopped glass fibers while simultaneously conveying a catalyst. The mixing and reaction unit mixes the monomers and the catalyst.

Description

Technical Field

[0001] This invention relates to the field of mold forming technology, specifically to an injection molding device and process for automotive plastic parts with a material equalization function. Background Technology

[0002] Polydicyclopentadiene (PDCPD) is an advanced thermosetting engineering plastic used in reaction injection molding (RIM) to manufacture high-performance automotive parts (such as large body panels and fairings). The process involves mixing low-viscosity two-component liquid monomers (A / B components) under high pressure in a mixing head, then injecting the mixture into a sealed mold. Within the mold, a rapid chemical reaction occurs, leading to cross-linking and curing. Compared to traditional melt injection molding of thermoplastics, the PDCPD-RIM process offers advantages such as lower energy consumption, lower internal stress, and the ability to mold large, thin-walled products. However, its unique chemical reaction molding mechanism presents three core challenges to mold design that traditional injection molds cannot address:

[0003] PDCPD involves low-ratio chemical foaming during the in-mold reaction to reduce product density and ensure complete filling of thick-walled areas. However, the "holding pressure" strategy used in traditional injection molding to address shrinkage marks is almost ineffective in RIM because once the material gels, it cannot be replenished externally. If left unchecked, a loose, porous structure easily forms inside the product, leading to a significant decrease in mechanical properties (especially impact strength and rigidity).

[0004] PDCPD is a thermosetting plastic that does not melt once cured, and its low molding shrinkage results in a different clamping force characteristic between the molded product and the mold cavity compared to thermoplastic plastics. Its cured product exhibits extremely high rigidity and brittleness. During demolding, even slight increases in ejection resistance or uneven stress can easily cause the product to "whiten" or even crack. This is particularly true for deep cavities, undercuts, or products with fine textures; traditional ejector pins and push plates are highly prone to causing punctures or tears.

[0005] PDCPD raw materials are extremely low-viscosity liquids when injected into the mold cavity, with permeability and fluidity far exceeding that of molten thermoplastics. This means that any micron-sized gaps or poor fits on the mold parting surface can be easily penetrated, forming thin, difficult-to-remove burrs. These burrs not only increase the cost of subsequent trimming processes but also damage the appearance quality of the finished product. Summary of the Invention

[0006] The purpose of this invention is to provide an injection molding apparatus and process for automotive plastic parts with a material equalization function, so as to solve the problems raised in the prior art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] The aforementioned injection molding device for automotive plastic parts with a material homogenization function includes a mounting base, a compaction unit, a flash removal unit, a demolding unit, a material homogenization conveying unit, and a mixing reaction unit. The mounting base is placed on a horizontal surface, the compaction unit is placed on a horizontal surface, the compaction unit is fixedly connected to the flash removal unit, the compaction unit has the function of preventing shrinkage marks from the mold, the demolding unit is fixedly connected to the compaction unit, the demolding unit is fixedly connected to the flash removal unit, the material homogenization conveying unit is fixedly connected to the mounting base, the material homogenization conveying unit is fixedly connected to the mixing reaction unit, and the mixing reaction unit is fixedly connected to the demolding unit.

[0009] Furthermore, the compaction unit includes a fixed box, a drive motor, a rotating drum, a push rod, a vibrating plate, and a mounting plate. The fixed box is placed on a horizontal surface, and its upper surface is fixedly connected to the mounting plate. The fixed end of the drive motor is fixedly installed on the inner wall of the fixed box, and its output end is fixedly connected to the rotating drum. One end of the push rod abuts against the outer surface of the rotating drum, and the other end of the push rod passes through the fixed box and is fixedly connected to the vibrating plate. The push rod is slidably connected to the mounting plate, and the vibrating plate is connected to the mounting plate via a telescopic spring.

[0010] Furthermore, the rotating drum is provided with multiple levers. In the vertical direction, the height of the levers gradually increases along the rotation direction of the drum, and a conductive sheet is provided on one side surface of the lever.

[0011] Furthermore, the deflash removal unit includes a spring cylinder, a pressure plate, a conductive cylinder, a guide rod, a drive coil, an electromagnet, a magnetic block, and a cutter. One end of the spring cylinder is fixedly installed on the inner wall of the fixed box, and the other end of the spring cylinder is fixedly connected to the pressure plate. The conductive cylinder is fixedly connected to the pressure plate, and the pressure plate abuts against the surface of the dial plate. The end of the pressure plate near the dial plate is an arc surface. The conductive cylinder is slidably connected to the guide rod, and a conductive ring is provided at the end of the conductive cylinder. The guide rod is fixedly connected to the fixed box and is located inside the spring cylinder. A drive coil is provided on the guide rod. The conductive cylinder is electrically connected to the conductive sheet on the dial plate. The electromagnet is electrically connected to the push rod. The electromagnet is connected to the magnetic block through a telescopic spring, and the cutter is fixedly connected to the magnetic block.

[0012] Furthermore, the end of the drive coil furthest from the inner wall of the fixed box is the current input terminal.

[0013] Furthermore, the demolding unit includes an upper mold, a lower mold, an electric telescopic rod, an air inlet pipe, a sliding plate, a return spring, and a winding tape. The electromagnet is fixedly connected to the upper mold, the cutter is slidably connected to the upper mold, the upper mold is fixedly connected to the telescopic end of the electric telescopic rod, the lower mold is fixedly connected to the fixed end of the electric telescopic rod, the fixed end of the electric telescopic rod is fixedly mounted on the upper surface of the mounting plate, the sliding plate is slidably mounted in the fixed box, the sliding plate divides the fixed box into an upper chamber and a lower chamber, the upper chamber is filled with air, and the lower chamber is a vacuum. Flexible airbags are provided in the mold cavities of the upper and lower molds, and air inlet pipes are provided in the upper and lower molds. The air inlet pipes are connected to the upper chamber of the fixed box through conduits. One end of the return spring is fixedly connected to the sliding plate, and the other end of the return spring is fixedly connected to the fixed box. One end of the winding tape is fixedly connected to the lower surface of the sliding plate, and the other end of the winding tape is fixedly connected to the output shaft of the drive motor. A controller is provided on the mounting base.

[0014] Furthermore, the material equalization and conveying unit has two sets. One set of the material equalization and conveying unit is used to convey monomers, and the other set of the material equalization and conveying unit is used to convey catalysts. The material equalization and conveying unit includes a material cylinder, a conveying motor, a spiral auger, a conveying cylinder, and a discharge pipe. The material cylinder and the conveying cylinder are connected by a conduit. The fixed end of the conveying motor is fixedly installed on the mounting base, and the output end of the conveying motor is fixedly connected to the spiral auger. The spiral auger is located inside the conveying cylinder. The conveying cylinder is fixedly connected to the mounting base, and a discharge pipe is provided at the end of the conveying cylinder. The conveying cylinder used to convey monomers is connected to the external chopped glass fiber conveying barrel through the conveying pipe.

[0015] Furthermore, the mixing reaction unit includes a mixing cylinder, a holding cylinder, and a reaction cylinder. The mixing cylinder is connected to the mounting base via a connecting rod. The holding cylinder is fixedly installed inside the mixing cylinder. The holding cylinder is connected to the discharge pipe via a conduit. An electric stirring rod is installed inside the holding cylinder. The reaction cylinder is installed at the bottom of the mixing cylinder. The holding cylinder and the reaction cylinder are connected via a conduit. A pressurization system is installed inside the holding cylinder.

[0016] Furthermore, the reaction cylinder is connected to the upper mold via a conduit, and an exhaust valve is provided at the connection conduit between the upper mold and the reaction cylinder.

[0017] The injection molding process for automotive plastic parts with material homogenization function includes the following steps:

[0018] S1, conveying;

[0019] Step S1 includes the following specific steps:

[0020] S11. The monomer and catalyst are conveyed to the next processing unit via a conveying mechanism;

[0021] S2, homogenization;

[0022] Step S2 includes the following specific steps:

[0023] S21. The monomer is premixed with chopped glass fiber by a conveying mechanism;

[0024] S3, Mixing;

[0025] Step S3 includes the following specific steps:

[0026] S31. The premixed monomers are mixed with the catalyst through a mixing mechanism;

[0027] S4, Molding;

[0028] Step S4 includes the following specific steps:

[0029] S41. The mixed material is conveyed to the mold for molding.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] 1. In this invention, during the gradual injection of the mixed material between the upper and lower molds, the controller starts the drive motor, thereby driving the rotary drum to rotate forward. As the rotary drum drives the platen to rotate forward, the push rod contacts the platen, which gradually increases in height. Under the pushing action of the platen, the distance the push rod moves upward each time gradually increases, thereby increasing the force of the push rod driving the vibrating plate to strike the lower surface of the lower mold. As the mixed material in the mold cavity gradually increases, in the initial stage of filling, the mixed material is small and has low viscosity. The small vibration force avoids material splashing and initially compacts the material, expelling surface air bubbles and laying a dense foundation for subsequent filling. In the middle stage of filling, the mixed material gradually accumulates, and the vibration force increases simultaneously, squeezing the gaps between the material and reducing internal porosity, thus avoiding shrinkage marks caused by volume shrinkage during curing. In the later stage of filling, the mixed material is close to the cavity, and the maximum vibration force is concentrated to compact the cavity surface and complex structures, such as rounded corners and rib roots, which are high-risk areas for shrinkage marks. Strong vibration allows the material to fully adhere to the cavity wall, compensating for curing shrinkage, thereby improving the mold forming quality.

[0032] 2. In this invention, after the mold is formed, the controller simultaneously controls the electric telescopic rod to extend, causing the upper mold to separate from the lower mold, and simultaneously controls the drive motor to start, causing the rotating drum and the push plate to rotate in opposite directions. As the gradually decreasing height of the push plate pushes the pressure plate's existing compression spring cylinder, it causes the conductive cylinder to gradually slide to the right along the smooth rod. During the contact between the conductive ring of the conductive cylinder and the drive coil, the effective coil connected to the circuit gradually decreases, reducing the resistance value of the connected resistor. This causes the output current through the conductive cylinder to the conductive plate to gradually increase. When the push rod contacts the conductive plate, the current is transmitted to the electromagnet through the push rod, energizing the electromagnet. Presenting the same polarity as the magnetic block, as the current received by the electromagnet gradually increases, the distance that the electromagnet pushes the magnetic block to move the cutter downwards gradually increases, thus removing the burrs generated at the joint between the upper and lower dies. At the same time, the cutting distance of the cutter gradually increases to adapt to the gradually rising upper die, avoiding the situation where the cutting distance of the cutter is equal each time, which would not be able to effectively remove the burrs at the joint. Online removal of burrs avoids increasing the cost of subsequent trimming processes and can improve the appearance quality of the product. When the push rod is not in contact with the conductive plate on the dial plate, the electromagnet is de-energized and does not present polarity, thus pulling the magnetic block and the cutter back to their original positions under the action of the self-restoring force of the extension spring.

[0033] 3. In this invention, during the raw material injection process, the drive motor rotates forward to rewind the tape, thereby pulling the slide plate downward and stretching the return spring. This draws gas between the flexible airbag and the mold into the upper chamber through the air inlet pipe. Under the pressure difference, the flexible airbag adheres tightly to the inner surfaces of the upper and lower molds, preventing any impact on the mold forming quality. After the mold forming is completed, the controller controls the drive motor to rotate in the reverse direction. At this time, under the restoring force of the return spring, the tape is stretched while the slide plate moves upward, delivering the gas in the upper chamber through the air inlet pipe to the space between the upper and lower molds and the flexible airbag. This causes the flexible airbag to inflate, quickly breaking the adhesion force in a gentle and evenly distributed manner. This avoids the problems of excessive resistance or uneven force distribution caused by traditional ejector pins and push plates, which can lead to product whitening or even cracking, thus improving the product yield. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the overall appearance and structure of the present invention;

[0035] Figure 2 This is a schematic diagram of the material conveying unit structure of the present invention;

[0036] Figure 3 This is a schematic diagram of the hybrid reaction unit structure of the present invention;

[0037] Figure 4 This is a schematic diagram of the internal structure of the fixing box of the present invention;

[0038] Figure 5 for Figure 4 Another perspective structural diagram;

[0039] Figure 6 This is a schematic diagram of the internal structure of the spring cylinder of the present invention;

[0040] Figure 7 This is a schematic diagram of the internal structure of the upper and lower molds of the present invention;

[0041] Figure 8 This is a schematic diagram showing the installation positions of the electromagnet, magnetic block, and cutter in this invention.

[0042] In the diagram: 1. Mounting base; 2. Compacting unit; 21. Fixing box; 22. Drive motor; 23. Rotary drum; 24. Push rod; 25. Vibrating plate; 26. Mounting plate; 27. Pulley; 3. Deburring unit; 31. Spring cylinder; 32. Pressure plate; 33. Conductive cylinder; 34. Smooth rod; 35. Drive coil; 36. Electromagnet; 37. Magnetic block; 38. Cutter; 4. Demolding unit; 41. Upper mold; 42. Lower mold; 43. Electric telescopic rod; 44. Air inlet pipe; 45. Slide plate; 46. Return spring; 47. Belt winding; 5. Material conveying unit; 51. Material cylinder; 52. Conveyor motor; 53. Spiral auger; 54. Conveying cylinder; 55. Discharge pipe; 6. Mixing reaction unit; 61. Mixing cylinder; 62. Container cylinder; 63. Reaction cylinder. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] Example: Figures 1-8 As shown, the present invention provides a technical solution:

[0045] like Figure 1 , Figure 4 As shown, an injection molding device for automotive plastic parts with a material equalization function includes a mounting base 1, a compaction unit 2, a flash removal unit 3, a demolding unit 4, a material equalization conveying unit 5, and a mixing reaction unit 6. The mounting base 1 is placed on a horizontal surface, the compaction unit 2 is placed on a horizontal surface, the compaction unit 2 is fixedly connected to the flash removal unit 3, and the compaction unit 2 has the function of preventing shrinkage marks from the mold. The demolding unit 4 is fixedly connected to the compaction unit 2 and the flash removal unit 3. The material equalization conveying unit 5 is fixedly connected to the mounting base 1, the material equalization conveying unit 5 is fixedly connected to the mixing reaction unit 6, and the mixing reaction unit 6 is fixedly connected to the demolding unit 4.

[0046] Mounting base 1 provides a fixed foundation for installation; compaction unit 2 is used for mold forming to ensure complete mold filling and avoid shrinkage marks that could affect molding quality; deflash removal unit 3 is used to remove deflashes from the mold after they appear, to avoid affecting the quality of the mold and adding subsequent trimming processes; demolding unit 4 is used for rapid demolding of the mold, to avoid damage to the mold and ensure quality; uniform material conveying unit 5 is used for uniform mixing of monomers and chopped glass fibers, while simultaneously conveying the catalyst; and mixing reaction unit 6 is used for mixing monomers and catalysts.

[0047] like Figure 4 , Figure 5 As shown, the compaction unit 2 includes a fixed box 21, a drive motor 22, a rotating drum 23, a push rod 24, a vibrating plate 25, and a mounting plate 26. The fixed box 21 is placed on a horizontal ground, and the upper surface of the fixed box 21 is fixedly connected to the mounting plate 26. The fixed end of the drive motor 22 is fixedly installed on the inner wall of the fixed box 21, and the output end of the drive motor 22 is fixedly connected to the rotating drum 23. One end of the push rod 24 abuts against the outer surface of the rotating drum 23, and the other end of the push rod 24 passes through the fixed box 21 and is fixedly connected to the vibrating plate 25. The push rod 24 is slidably connected to the mounting plate 26, and the vibrating plate 25 is connected to the mounting plate 26 through a telescopic spring.

[0048] like Figure 5 As shown, a plurality of levers 27 are provided on the rotating drum 23. In the vertical direction, the height of the levers 27 gradually increases along the rotation direction of the rotating drum 23, and a conductive sheet is provided on one side surface of the levers 27.

[0049] As the mixture is gradually injected between the upper mold 41 and the lower mold 42, the controller starts the drive motor 22, causing the rotating drum 23 to rotate forward. As the rotating drum 23 drives the dial plate 27 to rotate forward, the push rod 24 contacts the dial plate 27, which gradually increases in height. Under the pushing action of the dial plate 27, the distance the push rod 24 moves upward each time gradually increases, thus increasing the force with which the push rod 24 drives the vibrating plate 25 to strike the lower surface of the lower mold 42. Because the amount of mixture in the mold cavity gradually increases, the mixture... With low viscosity and minimal vibration, the material is prevented from splashing. At the same time, the material is initially compacted, and surface air bubbles are expelled, laying a dense foundation for subsequent filling. In the middle stage of filling, the mixture gradually accumulates, and the vibration intensity increases simultaneously to compress the gaps between the materials, reduce internal porosity, and prevent shrinkage marks caused by volume shrinkage during curing. In the later stage of filling, when the mixture is close to full cavity, the maximum vibration intensity is concentrated to compact the cavity surface and complex structures, such as rounded corners and rib roots, which are high-risk areas for shrinkage marks. Strong vibration allows the material to fully adhere to the cavity wall, compensating for curing shrinkage, thereby improving the mold forming quality.

[0050] like Figure 6 , Figure 8As shown, the deflash removal unit 3 includes a spring cylinder 31, a pressure plate 32, a conductive cylinder 33, a guide rod 34, a drive coil 35, an electromagnet 36, a magnetic block 37, and a cutter 38. One end of the spring cylinder 31 is fixedly installed on the inner wall of the fixed box 21, and the other end of the spring cylinder 31 is fixedly connected to the pressure plate 32. The conductive cylinder 33 is fixedly connected to the pressure plate 32. The pressure plate 32 abuts against the surface of the dial plate 27. The end of the pressure plate 32 near the dial plate 27 is an arc surface. The conductive cylinder 33 is slidably connected to the guide rod 34. A conductive ring is provided at the end of the conductive cylinder 33. The guide rod 34 is fixedly connected to the fixed box 21 and is located inside the spring cylinder 31. A drive coil 35 is provided on the guide rod 34. The conductive cylinder 33 is electrically connected to the conductive sheet on the dial plate 27. The electromagnet 36 is electrically connected to the push rod 24. The electromagnet 36 is connected to the magnetic block 37 through a telescopic spring. The cutter 38 is fixedly connected to the magnetic block 37.

[0051] like Figure 6 As shown, the end of the drive coil 35 furthest from the inner wall of the fixed box 21 is the current input terminal.

[0052] After the mold is formed, the controller controls the electric telescopic rod 43 to extend, causing the upper mold 41 to separate from the lower mold 42. Simultaneously, it controls the drive motor 22 to start, causing the rotating drum 23 and the lever 27 to rotate in opposite directions. As the lever 27, whose height gradually decreases, pushes the pressure plate 32 against the existing compression spring cylinder 31, the conductive cylinder 33 gradually slides to the right along the smooth rod 34. During the contact between the conductive ring of the conductive cylinder 33 and the drive coil 35, the effective coil in the circuit gradually decreases, reducing the resistance value and thus increasing the output current from the conductive cylinder 33 to the conductive plate. When the push rod 24 contacts the conductive plate, the current is transmitted through the push rod 24 to the electromagnet 36, causing the electromagnet 36 to become energized. With the same polarity as the magnetic block 37, as the current received by the electromagnet 36 gradually increases, the distance that the electromagnet 36 pushes the magnetic block 37 to move the cutter 38 downward gradually increases, thus removing the burrs generated at the joint of the upper mold 41 and the lower mold 42. At the same time, the downward distance of the cutter 38 gradually increases to adapt to the gradually rising upper mold 41, avoiding the situation where the downward distance of the cutter 38 is equal each time, which would prevent the burrs at the joint from being effectively removed. Online removal of burrs avoids increasing the cost of subsequent trimming processes and can improve the appearance quality of the product. When the push rod 24 is not in contact with the conductive sheet on the dial plate 27, the electromagnet 36 is de-energized and does not exhibit polarity, thus pulling the magnetic block 37 and the cutter 38 back to their original positions under the action of the self-restoring force of the extension spring.

[0053] like Figures 3-5 , Figure 7As shown, the demolding unit 4 includes an upper mold 41, a lower mold 42, an electric telescopic rod 43, an air inlet pipe 44, a sliding plate 45, a return spring 46, and a winding tape 47. An electromagnet 36 is fixedly connected to the upper mold 41, and a cutter 38 is slidably connected to the upper mold 41. The upper mold 41 is fixedly connected to the telescopic end of the electric telescopic rod 43, and the lower mold 42 is fixedly connected to the fixed end of the electric telescopic rod 43. The fixed end of the electric telescopic rod 43 is fixedly installed on the upper surface of the mounting plate 26. The sliding plate 45 is slidably installed inside the fixed box 21, dividing the fixed box 21 into an upper chamber. The upper chamber is filled with air, while the lower chamber is a vacuum. Flexible airbags are installed inside the mold cavities of the upper mold 41 and the lower mold 42. Air inlet pipes 44 are installed inside the upper mold 41 and the lower mold 42. The air inlet pipes 44 are connected to the upper chamber of the fixed box 21 through a conduit. One end of the return spring 46 is fixedly connected to the slide plate 45, and the other end of the return spring 46 is fixedly connected to the fixed box 21. One end of the winding tape 47 is fixedly connected to the lower surface of the slide plate 45, and the other end of the winding tape 47 is fixedly connected to the output shaft of the drive motor 22. A controller is installed on the mounting base 1.

[0054] During the raw material injection process, the drive motor 22 rotates in the forward direction, driving the tape 47 to rewind. This pulls the slide plate 45 downward while stretching the return spring 46, drawing the gas between the flexible airbag and the mold into the upper chamber through the air inlet pipe 44. Under the action of the pressure difference, the flexible airbag adheres tightly to the inner surfaces of the upper mold 41 and the lower mold 42, avoiding affecting the molding quality. After the mold is formed, the controller controls the drive motor 22 to rotate in the reverse direction. At this time, under the action of the return spring 46's own restoring force, the tape 47 is pulled to elongate while the slide plate 45 moves upward, delivering the gas in the upper chamber through the air inlet pipe 44 to the space between the upper mold 41, the lower mold 42 and the flexible airbag. This causes the flexible airbag to inflate, quickly breaking the adhesion force in a gentle and evenly distributed manner. This avoids the phenomenon of whitening or even cracking of products caused by the slightly greater resistance or uneven force of traditional ejection methods such as ejector pins and push plates, thereby improving the product yield.

[0055] like Figure 2 As shown, there are two sets of uniform material conveying units 5. One set of uniform material conveying units 5 is used to convey monomers, and the other set of uniform material conveying units 5 is used to convey catalysts. The uniform material conveying unit 5 includes a material cylinder 51, a conveying motor 52, a spiral auger 53, a conveying cylinder 54, and a discharge pipe 55. The material cylinder 51 and the conveying cylinder 54 are connected by a conduit. The fixed end of the conveying motor 52 is fixedly installed on the mounting base 1. The output end of the conveying motor 52 is fixedly connected to the spiral auger 53. The spiral auger 53 is located inside the conveying cylinder 54. The conveying cylinder 54 is fixedly connected to the mounting base 1. The end of the conveying cylinder 54 is provided with a discharge pipe 55. The conveying cylinder 54 used to convey monomers is connected to the external chopped glass fiber conveying barrel through a conveying pipe.

[0056] The controller starts the conveyor motor 52, which drives the auger 53 to rotate, conveying the monomers that have passed through the material cylinder 51 into the conveyor cylinder 54. At the same time, under the action of the auger 53, the chopped glass fiber and the monomers are evenly mixed to achieve premixing of the material. After premixing, the premixed material is discharged through the discharge pipe 55.

[0057] like Figure 3 As shown, the mixing reaction unit 6 includes a mixing cylinder 61, a holding cylinder 62, and a reaction cylinder 63. The mixing cylinder 61 is connected to the mounting base 1 via a connecting rod. The holding cylinder 62 is fixedly installed inside the mixing cylinder 61. The holding cylinder 62 is connected to the discharge pipe 55 via a conduit. An electric stirring rod is installed inside the holding cylinder 62. The reaction cylinder 63 is installed at the bottom of the mixing cylinder 61. The holding cylinder 62 and the reaction cylinder 63 are connected via a conduit. A pressurization system is installed inside the holding cylinder 62.

[0058] like Figure 3 As shown, the reaction cylinder 63 is connected to the upper mold 41 via a conduit, and an exhaust valve is provided at the connection conduit between the upper mold 41 and the reaction cylinder 63.

[0059] The premixed material discharged from the discharge pipe 55 enters the container 62 inside the mixing tank. Under the action of the electric stirring rod, it undergoes secondary stirring and mixing to improve the uniformity of the mixture. Then, the pressurization system sprays the mixture and catalyst at high speed into the reaction cylinder 63 for reaction. After the reaction is completed, it is transported to the mold cavities of the upper mold 41 and the lower mold 42.

[0060] The injection molding process for automotive plastic parts with material homogenization function includes the following steps:

[0061] S1, conveying;

[0062] Step S1 includes the following specific steps:

[0063] S11. The monomer and catalyst are conveyed to the next processing unit via a conveying mechanism;

[0064] S2, homogenization;

[0065] Step S2 includes the following specific steps:

[0066] S21. The monomer is premixed with chopped glass fiber by a conveying mechanism;

[0067] S3, Mixing;

[0068] Step S3 includes the following specific steps:

[0069] S31. The premixed monomers are mixed with the catalyst through a mixing mechanism;

[0070] S4, Molding;

[0071] Step S4 includes the following specific steps:

[0072] S41. The mixed material is conveyed to the mold for molding.

[0073] Working principle of the invention:

[0074] As the mixture is gradually injected between the upper mold 41 and the lower mold 42, the controller starts the drive motor 22, causing the rotating drum 23 to rotate forward. As the rotating drum 23 drives the dial plate 27 to rotate forward, the push rod 24 contacts the dial plate 27, which gradually increases in height. Under the pushing action of the dial plate 27, the distance the push rod 24 moves upward each time gradually increases, thus increasing the force with which the push rod 24 drives the vibrating plate 25 to strike the lower surface of the lower mold 42. Because the amount of mixture in the mold cavity gradually increases, the mixture... With low viscosity and minimal vibration, the material is prevented from splashing. At the same time, the material is initially compacted, and surface air bubbles are expelled, laying a dense foundation for subsequent filling. In the middle stage of filling, the mixture gradually accumulates, and the vibration intensity increases simultaneously to compress the gaps between the materials, reduce internal porosity, and prevent shrinkage marks caused by volume shrinkage during curing. In the later stage of filling, when the mixture is close to full cavity, the maximum vibration intensity is concentrated to compact the cavity surface and complex structures, such as rounded corners and rib roots, which are high-risk areas for shrinkage marks. Strong vibration allows the material to fully adhere to the cavity wall, compensating for curing shrinkage, thereby improving the mold forming quality.

[0075] After the mold is formed, the controller controls the electric telescopic rod 43 to extend, causing the upper mold 41 to separate from the lower mold 42. Simultaneously, it controls the drive motor 22 to start, causing the rotating drum 23 and the lever 27 to rotate in opposite directions. As the lever 27, whose height gradually decreases, pushes the pressure plate 32 against the existing compression spring cylinder 31, the conductive cylinder 33 gradually slides to the right along the smooth rod 34. During the contact between the conductive ring of the conductive cylinder 33 and the drive coil 35, the effective coil in the circuit gradually decreases, reducing the resistance value and thus increasing the output current from the conductive cylinder 33 to the conductive plate. When the push rod 24 contacts the conductive plate, the current is transmitted through the push rod 24 to the electromagnet 36, causing the electromagnet 36 to become energized. With the same polarity as the magnetic block 37, as the current received by the electromagnet 36 gradually increases, the distance that the electromagnet 36 pushes the magnetic block 37 to move the cutter 38 downward gradually increases, thus removing the burrs generated at the joint of the upper mold 41 and the lower mold 42. At the same time, the downward distance of the cutter 38 gradually increases to adapt to the gradually rising upper mold 41, avoiding the situation where the downward distance of the cutter 38 is equal each time, which would prevent the burrs at the joint from being effectively removed. Online removal of burrs avoids increasing the cost of subsequent trimming processes and can improve the appearance quality of the product. When the push rod 24 is not in contact with the conductive sheet on the dial plate 27, the electromagnet 36 is de-energized and does not exhibit polarity, thus pulling the magnetic block 37 and the cutter 38 back to their original positions under the action of the self-restoring force of the extension spring.

[0076] During the raw material injection process, the drive motor 22 rotates in the forward direction, driving the tape 47 to rewind. This pulls the slide plate 45 downward while stretching the return spring 46, drawing the gas between the flexible airbag and the mold into the upper chamber through the air inlet pipe 44. Under the action of the pressure difference, the flexible airbag adheres tightly to the inner surfaces of the upper mold 41 and the lower mold 42, avoiding affecting the molding quality. After the mold is formed, the controller controls the drive motor 22 to rotate in the reverse direction. At this time, under the action of the return spring 46's own restoring force, the tape 47 is pulled to elongate while the slide plate 45 moves upward, delivering the gas in the upper chamber through the air inlet pipe 44 to the space between the upper mold 41, the lower mold 42 and the flexible airbag. This causes the flexible airbag to inflate, quickly breaking the adhesion force in a gentle and evenly distributed manner. This avoids the phenomenon of whitening or even cracking of products caused by the slightly greater resistance or uneven force of traditional ejection methods such as ejector pins and push plates, thereby improving the product yield.

[0077] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. An injection molding apparatus for automotive plastic parts with a material equalization function, characterized in that: The aforementioned injection molding device for automotive plastic parts with a material homogenization function includes a mounting base, a compaction unit, a flash removal unit, a demolding unit, a material homogenization conveying unit, and a mixing and reaction unit. The mounting base is placed on a horizontal surface, the compaction unit is placed on a horizontal surface, the compaction unit is fixedly connected to the flash removal unit, the compaction unit has the function of preventing shrinkage marks from the mold, the demolding unit is fixedly connected to the compaction unit, the demolding unit is fixedly connected to the flash removal unit, the material homogenization conveying unit is fixedly connected to the mounting base, the material homogenization conveying unit is fixedly connected to the mixing and reaction unit, and the mixing and reaction unit is fixedly connected to the demolding unit. The compaction unit includes a fixed box, a drive motor, a rotating drum, a push rod, a vibrating plate, and a mounting plate. The fixed box is placed on a horizontal ground, and its upper surface is fixedly connected to the mounting plate. The fixed end of the drive motor is fixedly installed on the inner wall of the fixed box, and its output end is fixedly connected to the rotating drum. One end of the push rod abuts against the outer surface of the rotating drum, and the other end of the push rod passes through the fixed box and is fixedly connected to the vibrating plate. The push rod is slidably connected to the mounting plate, and the vibrating plate is connected to the mounting plate through a telescopic spring. The rotating drum is provided with multiple levers. In the vertical direction, the height of the levers gradually increases along the rotation direction of the drum. A conductive sheet is provided on one side surface of the lever. The deflash removal unit includes a spring cylinder, a pressure plate, a conductive cylinder, a guide rod, a drive coil, an electromagnet, a magnetic block, and a cutter. One end of the spring cylinder is fixedly installed on the inner wall of the fixed box, and the other end of the spring cylinder is fixedly connected to the pressure plate. The conductive cylinder is fixedly connected to the pressure plate, and the pressure plate abuts against the surface of the dial plate. The end of the pressure plate near the dial plate is an arc surface. The conductive cylinder is slidably connected to the guide rod, and a conductive ring is provided at the end of the conductive cylinder. The guide rod is fixedly connected to the fixed box and is located inside the spring cylinder. A drive coil is provided on the guide rod. The conductive cylinder is electrically connected to the conductive sheet on the dial plate. The electromagnet is electrically connected to the push rod. The electromagnet is connected to the magnetic block through a telescopic spring, and the cutter is fixedly connected to the magnetic block. The end of the drive coil furthest from the inner wall of the fixed box is the current input terminal.

2. The injection molding apparatus for automotive plastic parts with material equalization function according to claim 1, characterized in that: The demolding unit includes an upper mold, a lower mold, an electric telescopic rod, an air inlet pipe, a sliding plate, a return spring, and a winding tape. The electromagnet is fixedly connected to the upper mold, the cutter is slidably connected to the upper mold, the upper mold is fixedly connected to the telescopic end of the electric telescopic rod, and the lower mold is fixedly connected to the fixed end of the electric telescopic rod. The fixed end of the electric telescopic rod is fixedly mounted on the upper surface of the mounting plate. The sliding plate is slidably mounted inside the fixed box, dividing the fixed box into an upper chamber and a lower chamber. The upper chamber is filled with air, and the lower chamber is a vacuum. Flexible airbags are provided inside the mold cavities of the upper and lower molds. Air inlet pipes are provided inside the upper and lower molds and are connected to the upper chamber of the fixed box via conduits. One end of the return spring is fixedly connected to the sliding plate, and the other end of the return spring is fixedly connected to the fixed box. One end of the winding tape is fixedly connected to the lower surface of the sliding plate, and the other end of the winding tape is fixedly connected to the output shaft of the drive motor. A controller is provided on the mounting base.

3. The injection molding apparatus and process for automotive plastic parts with material equalization function according to claim 2, characterized in that: The material conveying unit has two sets. One set of material conveying units is used to convey monomers, and the other set is used to convey catalysts. The material conveying unit includes a material cylinder, a conveying motor, a spiral auger, a conveying cylinder, and a discharge pipe. The material cylinder and the conveying cylinder are connected by a conduit. The fixed end of the conveying motor is fixedly installed on the mounting base, and the output end of the conveying motor is fixedly connected to the spiral auger. The spiral auger is located inside the conveying cylinder. The conveying cylinder is fixedly connected to the mounting base, and a discharge pipe is provided at the end of the conveying cylinder. The conveying cylinder used to convey monomers is connected to the external chopped glass fiber conveying barrel through the conveying pipe.

4. The injection molding apparatus for automotive plastic parts with material equalization function according to claim 3, characterized in that: The mixing reaction unit includes a mixing cylinder, a holding cylinder, and a reaction cylinder. The mixing cylinder is connected to the mounting base via a connecting rod. The holding cylinder is fixedly installed inside the mixing cylinder. The holding cylinder is connected to the discharge pipe via a conduit. An electric stirring rod is installed inside the holding cylinder. The reaction cylinder is located at the bottom of the mixing cylinder. The holding cylinder and the reaction cylinder are connected via a conduit. A pressurization system is installed inside the holding cylinder.

5. The injection molding apparatus for automotive plastic parts with a material equalization function according to claim 4, characterized in that: The reaction cylinder is connected to the upper mold via a conduit, and an exhaust valve is provided at the connection conduit between the upper mold and the reaction cylinder.

6. An injection molding process for automotive plastic parts with material homogenization function, characterized in that: The injection molding apparatus for automotive plastic parts with a material equalization function as described in claim 1 includes the following steps: S1, conveying; Step S1 includes the following specific steps: S11. The monomer and catalyst are conveyed to the next processing unit via a conveying mechanism; S2, homogenization; Step S2 includes the following specific steps: S21. The monomer is premixed with chopped glass fiber by a conveying mechanism; S3, Mixing; Step S3 includes the following specific steps: S31. The premixed monomers are mixed with the catalyst through a mixing mechanism; S4, Molding; Step S4 includes the following specific steps: S41. The mixed material is conveyed to the mold for molding.

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