CN115972478A - Polymer melt composite vibration injection molding device - Google Patents

Abstract

The invention discloses a polymer melt composite vibration injection molding device, which comprises an injection molding machine, a composite vibration system and an injection mold, wherein the most difference from common injection molding is the composite vibration system of the device. The composite vibration system comprises a medium-low frequency hydraulic vibration system and a high-frequency ultrasonic vibration system, wherein the hydraulic vibration system comprises a hydraulic pump, a rotary valve, a hydraulic cylinder, a vibration rod and the like, the vibration rod extends into a polymer melt flow passage, the number of the vibration rods is even, and the vibration rods can be divided into two groups which can simultaneously perform reciprocating vibration in the same direction or in the opposite direction so as to realize pressure vibration or shearing vibration of the melt. The ultrasonic vibration system consists of an ultrasonic generator, an energy transducer, an amplitude transformer and a vibration rod, and the ultrasonic vibration rod extends into the polymer melt runner and directly acts on the melt. The device can obviously reduce the viscosity of the melt, and is suitable for thin-wall or large-scale injection molding parts which are difficult to fill the mold and injection molding parts with more weld marks or poorer weld mark strength.

Description

Polymer melt composite vibration injection molding device

Technical Field

The invention relates to the field of polymer processing equipment, in particular to a polymer melt composite vibration injection molding device capable of improving the mold filling performance of a polymer and reducing weld marks.

Background

The existing mainstream polymer melt injection molding device can only provide a simple shear field, and the generated shear direction, shear rate and the like are not changed. This simple shear field causes slippage of the molecular chains between the layers of the fluidized bed in a direction perpendicular to the direction of flow, thereby releasing the entanglement sites to some extent, causing a phenomenon of viscosity reduction, known as "shear thinning". Although the viscosity reduction caused by shear thinning is beneficial to the processing process, the shear rate is constant and the shear time is short, when the recovery entanglement caused by the thermal motion of the molecular chain and the shear-induced disentanglement reach the dynamic balance, the entanglement state of the molecular chain is kept unchanged, the disentanglement cannot be continued, and the viscosity is also kept unchanged.

Chinese invention with publication number CN112793098A discloses an injection molding machine capable of improving flowability of high polymer material, and specifically discloses an injection molding machine which can generate good mixing effect during material conveying by arranging a plurality of rows of parallel and convex ribs on the outer surface of a mandrel of a disentangling mechanism of the injection molding machine, and can increase uniformity of shearing effect on a plastic melt, thereby avoiding the disadvantage of poor disentangling effect of the material caused by non-uniform shearing in the layer thickness direction; meanwhile, the space between the ribs is large, so that the capacity of the melt can be effectively increased, and the disentangling efficiency is improved. The problems that exist are mainly that: 1. the disentanglement mode is single, mainly depends on the cutting mode, and the disentanglement effect is limited; 2. the polymer melt enters the device in a direction different from that of the injection molding device, and an additional power device (a driving motor) is required to make the polymer melt flow in a specified direction for injection molding.

Chinese patent publication No. CN110815628A discloses a polymer melt disentangling device, which specifically discloses a polymer melt disentangling device that applies a circumferential rotation stress field or a circumferential vibration stress field or a composite motion stress field in which circumferential rotation and circumferential vibration are superimposed to a melt, so that molecular chains in the melt gradually move away in the circumferential shear field or the circumferential vibration field, especially in the composite stress field in which circumferential shear and circumferential vibration are superimposed, while the stress direction is constantly changed by one relaxation, thereby achieving a high disentangling effect. It has the following problems: 1. the disentanglement mode is single, mainly depends on a mechanical mode (vibration and shearing), and the disentanglement effect is limited; 2. the polymer melt enters the device in a direction different from that of the injection molding device, and an additional power device (a driving motor) is required to make the polymer melt flow in a specified direction for injection molding.

The chinese patent publication No. CN114633448A discloses a testing machine with an integrated function of broadband amplitude vibration test/rheological measurement, and specifically discloses that a broadband amplitude vibration field is formed by simultaneously using high-amplitude low-frequency mechanical vibration and high-frequency low-amplitude ultrasonic vibration to improve the processing efficiency and mechanical properties of a polymer. However, it has the following technical problems:

1. in fact, the testing instrument is difficult to be directly applied to industrial production by technicians in the field, and has complex structure and higher cost and requirements on manufacturing, installation and use;

2. the material inlet, the material flow channel and the material outlet are vertical to each other, the flow direction of the polymer in the material flow channel needs to pass through 2 90-degree right angles, obviously, the right angles inevitably cause the flow speed of the polymer melt at the position to be slowed down, and the temperature to be reduced, but as the material flow channel is a test instrument, the material flow channel only needs to output the material at the material outlet, and even if the material flow property is poor or the temperature is low, the performance of the material flow channel is not influenced in the subsequent experiment, and the material flow channel is a great problem if the material flow channel is used in industrial production;

3. the mechanical vibration direction of the polymer melt reciprocating along the flow direction of the polymer melt is equivalent to that only a single-direction shear flow field is applied in the melt flow direction, the melt is in frictional shear with the wall surfaces of an upper die and a lower die, the shear field is consistent with the shear field in the conventional injection molding process in principle, only two sides push the melt to shear in a reciprocating manner, the effective disentanglement is difficult to realize by the shear field, and in the direction perpendicular to the flow direction, because of the speed difference between layers, macromolecules can slide relatively, so that the aggregation entanglement point and the topological entanglement point are both released to a certain degree, and the viscosity is reduced. The disentanglement is inevitable during the processing, but the disentanglement effect is general, and the deep disentanglement effect and the high-efficiency disentanglement effect cannot be achieved.

4. The discharge is discontinuous and there are no problems in the experimental application, but in the industry it is a discontinuous production, which is clearly unacceptable. The continuous supply of the polymer melt can be ensured by connecting a plurality of testing machines in parallel and combining the testing machines to match the time for discharging materials from the outlets of the testing machines, the complexity of the system, the construction cost of the system and the like are increased by times due to the parallel connection of the testing machines, and the problem that the continuous supply is realized by the cooperation of the testing machines is a challenge for the technical personnel in the field and is difficult to realize in industrial production.

Disclosure of Invention

Aiming at the technical problems, the application provides a polymer melt injection molding device which has a simple structure and is suitable for industrial production and application and has hydraulic vibration and ultrasonic vibration.

In order to achieve the above object, the present application provides the following technical solutions:

the polymer melt compound vibration injection molding device comprises an injection molding machine, a compound vibration device and an injection mold;

the injection molding machine is used for plasticizing a polymer, and a plasticized polymer melt flows through the composite vibration device and then enters an injection mold; the injection mold is used for forming polymer melt;

the composite vibration device comprises a material passing die, a hydraulic vibration module and an ultrasonic module;

the material passing mold is formed by combining an upper mold and a lower mold, and a runner which penetrates through two ends of the material passing mold and is used for polymer melt to flow is arranged on a parting surface of the material passing mold; the upper die is provided with at least two first through holes, and the lower die is provided with at least one second through hole; the first through hole and the second through hole are respectively vertical to and communicated with the flow channel;

the hydraulic vibration module comprises a vibration rod and a hydraulic cylinder; the vibrating rod is arranged in the first through hole and extends into the flow channel, one end, far away from the upper die, of the vibrating rod is connected with a hydraulic cylinder, and the hydraulic cylinder is used for driving the vibrating rod to do piston motion in the first through hole;

the ultrasonic module comprises an ultrasonic vibration head and an amplitude transformer; the ultrasonic vibration head is arranged at one end of the amplitude transformer; the amplitude transformer is arranged in the second through hole, and the ultrasonic vibration head extends into the flow channel.

And two ends of the flow channel are respectively communicated with the injection molding machine and the injection mold.

In some preferred embodiments, the parting surfaces of the upper and lower molds are stepped to facilitate positioning.

In some preferred embodiments, a convergent boss is further arranged at a position, opposite to the second through hole, of the surface of the flow channel, and the convergent boss is used for reducing the thickness of the flow channel at the position; the cross section of the flow channel is rectangular, and the width of the flow channel is not less than the diameter of any one of the first through hole and the second through hole.

In some preferred embodiments, a wear-resistant sleeve is arranged in the first through hole, the inner surface of the wear-resistant sleeve is in clearance fit with the vibrating rod, and the outer surface of the wear-resistant sleeve is in interference fit with the first through hole; and a flexible sleeve is arranged in the second through hole.

In some preferred embodiments, the hydraulic cylinder comprises a horizontal chute; the vibrating rod is connected with the horizontal sliding groove through a sliding block arranged at one end far away from the die.

In some preferred embodiments, one side of the horizontal sliding groove, which is far away from the slot, is provided with a plurality of third through holes, and the sliding block is provided with threaded blind holes at positions corresponding to the third through holes.

In some preferred embodiments, the hydraulic cylinder further comprises a piston rod; the movable end of the piston rod is connected with the horizontal chute.

Advantageous effects

1. The polymer melt runner is reasonable in design, can be connected with an injection molding machine at the feed end of the runner, and is connected with an injection mold at the discharge end, so that the industrial polymer melt injection molding production application is realized;

2. the disentanglement effect is realized through the composite external force field superposed by ultrasonic vibration and hydraulic vibration, the viscosity of the polymer melt can be greatly reduced, and the device has three modes: the ultrasonic vibration mode, the hydraulic vibration mode and the hydraulic-ultrasonic composite vibration mode have the advantages that the ultrasonic vibration has a better effect on reducing the viscosity of the thermosensitive polymer, the hydraulic vibration has a better effect on the thermosensitive polymer, and the composite vibration can realize the superposition or synergistic effect of the ultrasonic vibration and the thermosensitive polymer. The reduction of the viscosity can greatly reduce the injection pressure on the premise of ensuring the filling effect, reduce the injection molding difficulty, shorten the cooling time and realize the low-energy-consumption and high-efficiency injection molding of the polymer with high viscosity and difficult processing; the injection molding temperature can be greatly reduced under the condition of keeping the melt viscosity substantially unchanged, and the degradation in the molding process can be reduced by low-temperature molding, so that the overall temperature difference of the product is reduced, and the internal stress is reduced; the defects of warping deformation, underfilling, welding marks and the like caused by insufficient melt flowability in the molding process of thin-wall and large-size injection molded parts can be effectively overcome, and the product quality is improved;

3. the macromolecule after chain disentanglement has higher movement capability, the ordering process of the system is accelerated, the crystallization capability of the polymer is enhanced, and the 'configuration' process of the crystal form of the polymer melt is easier to control and adjust, so that special crystal structures such as a crystal string structure and a columnar crystal structure can be generated under the induction of an external field or a nucleating agent, the crystal perfection degree can be improved, an oriented structure is generated, and the physical and mechanical properties of the product are obviously improved.

Drawings

FIG. 1 is a schematic diagram of the overall structure of an apparatus according to a preferred embodiment of the present invention;

FIG. 2 is a schematic diagram showing the overall structure of an apparatus according to another preferred embodiment of the present invention;

FIG. 3 is a schematic axial view of a composite vibration device according to a preferred embodiment of the present invention;

FIG. 4 is a schematic front view of a composite vibration device according to a preferred embodiment of the present invention;

FIG. 5 is a schematic side view of a composite vibration device in accordance with a preferred embodiment of the present invention;

FIG. 6 is an enlarged schematic view of the main structure of section A-A inbase:Sub>A preferred embodiment of the present invention;

FIG. 7 isbase:Sub>A schematic structural view ofbase:Sub>A connecting flange andbase:Sub>A nozzle ofbase:Sub>A material passing mold mounting injection molding machine of section A-A inbase:Sub>A preferred embodiment of the present invention;

FIG. 8 is an enlarged schematic view of the cross-sectional structure A-A of the passing die inbase:Sub>A preferred embodiment of the present invention;

FIG. 9 is an enlarged schematic view of a cross-sectional structure B-B of a material passing mold in a preferred embodiment of the present invention;

FIG. 10 is a schematic representation of the LDPE processability results of a preferred experimental example of the present invention;

FIG. 11 is a schematic diagram showing the PLA processability results in a preferred example of the invention;

in the figure: 1. an injection molding machine; 2. a composite vibration device; 3. injection molding of the mold; 4. connecting the injection molding machine with a flange; 5. a nozzle; 21. a material passing mold; 22. a hydraulic vibration module; 23. an ultrasonic module; 210. converging the boss; 211. an upper die; 212. a lower die; 213. a feeding end; 214. a discharge end; 215. a flow channel; 216. a first through hole; 217. a second through hole; 218. a wear-resistant sleeve; 219. a flexible sleeve; 221. a vibrating rod; 222. a hydraulic cylinder; 231. an amplitude transformer; 232. an ultrasonic vibration head; 2221. a horizontal chute; 2222. a piston rod; 2223. a threaded blind hole; 2224. a third through hole;

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described below with reference to the accompanying drawings. In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", and the like, are used in the orientations and positional relationships indicated in the drawings, which are based on the orientations and positional relationships indicated in the drawings, and are used for convenience of description and simplicity of description, but do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

The embodiment discloses a polymer melt composite vibration injection molding device, which comprises an injection molding machine 1, a composite vibration device 2, an injection mold 3, an injection molding machine connecting flange 4 and a nozzle 5, wherein the injection molding machine connecting flange is provided with a vibration cavity;

the injection molding machine 1 is used for plasticizing polymer materials, and a plasticized polymer melt flows through the composite vibration device 2 and then enters the injection mold 3; the plasticized polymer melt flows through a composite vibration device 2 and then enters an injection mold 3; the injection mold 3 is used for molding a polymer melt;

as shown in fig. 1, an example is given of directly connecting the injection molding machine 1 with the compound vibration device 2, and then connecting the injection mold 3 after the discharge end of the compound vibration device 2 is connected with the nozzle, in other preferred embodiments, as shown in fig. 2, the injection molding machine 1 can be connected with the nozzle first, and then the compound vibration device 2 and the injection mold 3 are connected in sequence. The specific use of the two embodiments described above can be determined by the person skilled in the art according to the actual needs in the field. It should be understood that, since the injection molding machine 1 and the injection mold 3 are not the focus of the present application, they are shown in simplified drawings and are not further defined in the description, and those skilled in the art can adopt the structural arrangements commonly used in the art.

The composite vibration device 2 comprises a material passing die 21, a hydraulic vibration module 22 and an ultrasonic module 23;

the material passing mold 21 is formed by combining an upper mold 211 and a lower mold 212, and a runner 215 which penetrates through two ends of the material passing mold 21 and is used for polymer melt to flow is arranged on the parting surface of the material passing mold 21; the upper mold 211 is provided with at least two first through holes 216, and the lower mold 212 is provided with at least one second through hole 217; the first through hole 216 and the second through hole 217 are respectively vertical to and communicated with the flow channel 215; in some preferred embodiments, in order to achieve more precise positioning of the upper and lower molds 212 when they are closed and to enable the higher pressure during the injection process to cause the material to overflow the runner 215 into the parting plane, thereby causing material leakage, the parting planes of the upper mold 211 and the lower mold 212 are stepped to facilitate positioning, for example, by providing matching grooves and shoulders. The cross-sectional size of the flow channel 215 is generally small, and in order to make the vibration module and the ultrasonic module 23 contact the polymer melt in the flow channel 215 more sufficiently, it is considered to design the cross-sectional shape of the flow channel 215 to be rectangular, and the width of the flow channel is not less than the diameter of any one of the first through hole 216 and the second through hole 217.

The hydraulic vibration module 22 comprises a vibration rod 221 and a hydraulic cylinder 222; the vibrating rod 221 is installed in the first through hole 216 and extends into the flow channel 215, one end of the vibrating rod 221, which is far away from the upper die 211, is connected with a hydraulic cylinder 222, and the hydraulic cylinder 222 is used for driving the vibrating rod 221 to perform piston motion in the first through hole 216; it should be understood that the vibrating rod 221 may be driven by a variety of driving methods, such as mechanical driving, electric driving, and hydraulic driving. In the present application, the vibration frequency of the vibration rod 221 is 0-200Hz and the vibration amplitude is 0-140mm, depending on the driving mode, and in practice, the vibration amplitude is sufficient, and generally not more than 10Hz.

The ultrasonic module 23 comprises an ultrasonic vibration head 232 and a horn 231; the ultrasonic vibration head 232 is arranged at one end of the amplitude transformer 231; the horn 231 is installed in the second through hole 217 and the ultrasonic vibration head 232 protrudes into the flow passage 215. It should be understood that the ultrasonic vibration module is a device commonly used in the art, and includes necessary components such as an ultrasonic transmitter, a transducer, a cooling device, an ultrasonic generator, and an electric parameter device in addition to the ultrasonic vibration head 232 and the horn 231, so that the present application does not describe structures and components not directly related to the present technical solution. Since the ultrasonic vibration head 232 is inserted into the lower mold 212 from bottom to top in the present application, the horn 231 should be provided with a connecting device for connecting and fixing, in some preferred embodiments, a flange; after the horn 231 is inserted in place, the horn 231 is fixedly connected to the lower mold 212 through the connecting flange. In other preferred embodiments, considering that the mold is generally a metal mold and the ultrasonic waves are not directly applied to the metal surface, a flexible sleeve 219 is disposed in the second through hole 217, the inner surface of the flexible sleeve 219 is in interference fit with the ultrasonic vibration head 232, and the outer surface of the flexible sleeve 219 is in transition fit with the second through hole 217. Preferably, the flexible sleeve 219 is a high temperature rubber.

In some preferred embodiments, the two ends of the runner 215 may be connected to the injection molding machine connecting flange 4 and the nozzle 5, respectively. It should be understood that the injection molding machine attachment flange 4 and the nozzle 5 are not essential components, but are only limited in this embodiment as a preferred embodiment, and that the injection molding machine attachment flange 4 and the nozzle 5 are both detachably connected, preferably flanged, to the blanking mold 21. The injection molding machine connecting flange 4 is used for connecting a mold and an injection molding machine, the injection molding machine can be any one of common injection molding machines in the field, and in order to realize industrial injection molding production, other necessary equipment such as an injection system, a mold closing system, a heating system, a cooling system, a control system and the like are all equipped by the technical personnel in the field according to needs, and are not repeated as the key points of the invention.

In order to enhance the effect of the ultrasonic vibration head 232 on the polymer melt in the runner 215 and increase the penetration of the ultrasonic wave, it is also considered in some preferred embodiments that a converging boss 210 is further provided on the surface of the runner 215 opposite to the second through hole 217 for reducing the thickness of the runner 215 at this point, thereby achieving the following effects: 1. the higher pressure is facilitated to be established on the two sides of the convergence boss 210 in the flow channel 215, so that the vibration module can better shear and stretch the polymer melt; 2. the thickness of the polymer melt is reduced at this location to allow better reception of the high frequency vibratory force field of the ultrasonic waves, allowing better penetration of the ultrasonic waves and thus better disentanglement.

It should be noted that from the perspective of melt disentanglement, in a simple shear force field generated by a single mechanical vibration, the cohesive entanglement perpendicular to the shear direction is pulled apart, while the influence on the cohesive entanglement parallel to the shear direction is not great, and when the topological entanglement is located at one end of the molecular chain, the macromolecular chain is likely to slip apart in the shear force field, and when the entanglement is in the middle of the macromolecular, the entanglement is more and more pulled in the pure shear force field and is difficult to detach, resulting in a limited degree of melt disentanglement.

In a single ultrasonic vibration field, the cavitation effect of ultrasonic waves is reduced due to the high viscosity of the polymer melt, the penetration capacity is limited, and the topological entanglement points can be loosened only by the single ultrasonic field under the condition of no shearing and stretching external fields, so that the relative slippage and disentanglement of molecular chains from the entanglement points are difficult to realize.

The design idea of the invention is that the ultra-high frequency impact is applied to the melt by utilizing the ultrasonic wave to instantly break the condensation entanglement in the melt, then the shear force field can enable the molecular chains to gradually loosen from the opened entanglement points and gradually pull apart under the action of a relaxed vibration field by combining with the high-frequency reciprocating vibration shear field, and the high disentanglement is realized.

Meanwhile, from the analysis of the intrinsic characteristics of molecular chain motion, the molecular weight of a high molecular chain has certain dispersibility and shows typical viscoelastic behavior characteristics, the response time of different molecular chains to an external field is inconsistent and is distributed in a time range (relaxation time spectrum), if the action of the external field changes at a certain moment, a part of the molecular chains can timely respond to the pace of changing with the external field, but the larger part of the molecular chains show different degrees of hysteresis and still move in the original mode, so that the motion conditions of all the molecular chains are different; the composite external field combined with different motion forms can cause disturbance to the melt to the maximum extent, and is beneficial to the 'opening' of entangled molecular chains.

In some preferred embodiments, a specific structural example is given in which the vibration rod 221 is connected to the hydraulic cylinder 222, and the hydraulic cylinder 222 includes a horizontal sliding groove 2221; the vibration rod 221 is connected to the horizontal sliding groove 2221 through a sliding block disposed at an end far away from the mold. During installation, one end of the vibration rod 221 with the sliding block slides into the horizontal sliding groove 2221, and the other end is inserted into the first through hole 216, so that the installation of the vibration rod 221 can be completed. In other preferred embodiments, in order to lock the vibrating rod 221 installed in place in the sliding chute, a plurality of third through holes 2224 are formed in one side of the horizontal sliding chute 2221 away from the slot, and threaded blind holes 2223 are formed in positions of the sliding block corresponding to the third through holes 2224. The position of the third through hole 2224 corresponds to the installation position of the vibration rod 221, and when the vibration rod 221 slides in the sliding groove to the right position, a bolt is screwed into the threaded blind hole 2223 through the third through hole 2224, so as to lock the position of the vibration rod 221. It should be understood that, in order to prevent the installed bolt head from being exposed to the surface of the horizontal sliding groove 2221, it is considered that the third through hole 2224 is provided as a stepped through hole.

In some preferred embodiments, a specific composition example of the hydraulic cylinder 222 is also given, and the hydraulic cylinder 222 further comprises a piston rod 2222; the movable end of the piston rod 2222 is connected to the horizontal sliding groove 2221. The piston rod 2222 may be any common hydraulic cylinder telescopic structure, and may also be a pneumatic cylinder, an electric cylinder, or other telescopic structures such as a mechanical telescopic structure, which is not further limited in this application, and a person skilled in the art may determine the specific form of the energy supply device according to the specific form of the piston rod 2222 and the conventional technology in the art, for example, when the piston rod 2222 adopts a hydraulic cylinder, the energy supply device includes a hydraulic pipe, a hydraulic pump, a liquid outlet tank, a hydraulic valve, a hydraulic control system, and other components. Furthermore, in order to adjust the expansion and contraction width of the piston rod 2222 and thus the vibration width of the vibration rod 221, an amplitude adjustment device such as an adjustment nut commonly used in the art may be further provided.

The working process of the present invention is explained as follows:

the molten compound flows out of the injection molding machine through the injection molding machine connecting flange 4 into the flow channel 215 in the feed-through mold 21, the cross-sectional dimension of the flow channel 215 being smaller than the discharge dimension of the injection molding machine connecting flange 4, so that the molten compound converges in the flow channel 215, resulting in a higher pressure and tensile convergence. The vibration rod 221 extends into the flow channel 215 when the piston moves under the action of the hydraulic cylinder 222, directly contacts and acts on the molten compound, directly acts on the molten compound with vibration acting force, and enables the molten compound to be compressed and released in the flow channel 215 in a reciprocating manner, and when the vibration rod 221 moves to the lowest end, the distance between the surface of the vibration rod 221 and the bottom surface of the flow channel 215 is small, so that a convergence flow channel 215 is formed, and the repeated stretching action of the molten compound is enhanced; as the vibration rod 221 reciprocates, the molten polymer is repeatedly compressed, released, and sheared and stretched. The flow channel 215 at the ultrasonic vibration head 232 is narrowed by the convergence boss 210, so that the flow channel 215 generates a convergence effect and increases the pressure of the molten compound, and the action time of the ultrasonic waves on the molten compound is prolonged. The molten compound, after the combined action of the mechanical vibration and the ultrasonic wave, enters the nozzle 5 through the discharge end 214, and is injected into the injection mold to be molded into a desired plastic product. The application has the advantages that the vibration action area is large, the vibration action is strong, the mechanical vibration stress field and the ultrasonic high-frequency stress field which are released by compression can be provided independently, the synergistic effect of the two stress fields can be provided, and effective regulation and control and efficient disentanglement of the processing performance of the polymer melt are realized.

Examples of the experiments

As shown in fig. 10 to fig. 11, the experimental examples take PLA (biodegradable plastic polylactic acid) and LDPE (low density polyethylene) as examples, and various properties of the materials produced by the polymer melt injection molding apparatus of the present application were studied.

After the ultrasonic and vibration composite force field is applied, the melt pressure and the apparent viscosity of PLA and LDPE entering the nozzle 5 are obviously reduced, which shows that the melt with high disentanglement degree after the composite external field treatment has excellent processability, and the device can effectively improve the injection molding speed, reduce the pressure and the melt viscosity of the nozzle 5 and continuously and efficiently inject a product with high mechanical property.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are given by way of illustration of the principles of the present invention, but that various changes and modifications may be made without departing from the spirit and scope of the invention, and such changes and modifications are within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims (7)

1. The polymer melt compound vibration injection molding device is characterized in that: comprises an injection molding machine (1), a composite vibration device (2) and an injection mold (3);

the injection molding machine (1) is used for plasticizing a polymer, and a plasticized polymer melt flows through the composite vibration device (2) and then enters the injection mold (3); the injection mould (3) is used for forming polymer melt;

the composite vibration device (2) comprises a material passing die (21), a hydraulic vibration module (22) and an ultrasonic module (23);

the material passing mold (21) is formed by combining an upper mold (211) and a lower mold (212), and a runner (215) which penetrates through two ends of the material passing mold (21) and is used for polymer melt to flow is arranged on a parting surface of the material passing mold (21); the upper die (211) is provided with at least two first through holes (216), and the lower die (212) is provided with at least one second through hole (217); the first through hole (216) and the second through hole (217) are respectively vertical to and communicated with the flow channel (215);

the hydraulic vibration module (22) comprises a vibration rod (221) and a hydraulic cylinder (222); the vibrating rod (221) is installed in the first through hole (216) and extends into the flow channel (215), one end, far away from the upper die (211), of the vibrating rod (221) is connected with a hydraulic cylinder (222), and the hydraulic cylinder (222) is used for driving the vibrating rod (221) to do piston motion in the first through hole (216);

the ultrasonic module (23) comprises an ultrasonic vibration head (232) and a variable amplitude rod (231); the ultrasonic vibration head (232) is arranged at one end of the amplitude transformer (231); the amplitude transformer (231) is arranged in the second through hole (217) and the ultrasonic vibration head (232) extends into the flow channel (215).

And the two ends of the flow channel (215) are respectively communicated with the injection molding machine (1) and the injection mold (3).

2. The polymer melt composite vibration injection molding apparatus of claim 1, wherein: the parting surfaces of the upper die (211) and the lower die (212) are stepped for convenient positioning.

3. The polymer melt composite vibration injection molding apparatus of claim 1, wherein: a convergent boss (210) is further arranged at the position, opposite to the second through hole (217), of the surface of the flow channel (215) and used for reducing the thickness of the flow channel (215) at the position; the cross section of the flow channel (215) is rectangular, and the width of the flow channel is not less than the diameter of any one of the first through hole (216) and the second through hole (217).

4. The polymer melt composite vibration injection molding apparatus of claim 1, wherein: a wear-resistant sleeve (218) is arranged in the first through hole (216), the inner surface of the wear-resistant sleeve (218) is in clearance fit with the vibrating rod (221), and the outer surface of the wear-resistant sleeve (218) is in interference fit with the first through hole (216); a flexible sleeve (219) is arranged in the second through hole (217).

5. The polymer melt composite vibration injection molding apparatus of claim 1, wherein: the hydraulic cylinder (222) comprises a horizontal chute (2221); the vibrating rod (221) is connected with the horizontal sliding groove (2221) through a sliding block arranged at one end far away from the die.

6. The polymer melt composite vibration injection molding apparatus of claim 5, wherein: one side of the horizontal sliding groove (2221) far away from the groove is provided with a plurality of third through holes (2224), and threaded blind holes (2223) are arranged at positions of the sliding block corresponding to the third through holes (2224).

7. The polymer melt composite vibration injection molding apparatus of claim 5, wherein: the hydraulic cylinder (222) further comprises a piston rod (2222); the movable end of the piston rod (2222) is connected with the horizontal sliding groove (2221).

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