Micro injection mold with adjustable frequency amplitude combined variable angle vibration flow channel structure

Abstract

This invention discloses a micro-injection mold with an adjustable frequency amplitude combined variable angle vibration flow channel structure, including a sprue bushing disposed in a fixed mold plate; the sprue bushing includes two oppositely arranged arc-shaped blocks, and a mechanical vibration block and an ultrasonic vibration block oppositely arranged between the two arc-shaped blocks; the arc-shaped blocks are fixed to the fixed mold plate; the mechanical vibration block and the ultrasonic vibration block are multiple blocks, each stacked layered between the two arc-shaped blocks; the mechanical vibration block, the ultrasonic vibration block, and the two arc-shaped blocks enclose an internal region that is a through flow channel; the flow channel has a variable angle structure, and from the inlet of the sprue bushing to the cavity, the inclination angle of the inner surfaces of the stacked mechanical vibration block and ultrasonic vibration block gradually changes, causing the cross-sectional area of ​​the flow channel to gradually increase. The mechanical vibration block and the ultrasonic vibration block are respectively connected to a vibration source, applying increased vibration to the polymer melt, reducing the viscosity of the polymer melt during injection molding, and improving fluidity and filling capacity.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of polymer microstructure manufacturing, and particularly relates to a micro injection mold with adjustable amplitude and angle vibration flow channel structure. BACKGROUND

[0002] Micro injection molding technology is a widely used technology, especially suitable for manufacturing micro-sized plastic parts, such as optical cameras, microfluidic chips, etc. These products usually require very high precision to ensure their performance and stability. And some products have harsh service conditions, such as aerospace, medical detection, etc., which also have very strict requirements on mechanical properties. However, in the production process of micro-sized plastic parts, due to the influence of scale effect, it is limited by processing conditions, and various defects are easily caused. For example, due to the increase of the viscosity of the polymer melt during the filling process, the flow resistance increases, the flow of the plastic material is uneven, causing the product surface to appear bending or twisting, and the weld mark is obvious; the gas generated by the polymer melt during the injection molding process is trapped in the micro cavity and cannot be smoothly discharged, causing product air pockets, burns, etc. Therefore, in order to ensure the quality and performance of micro-sized plastic parts, high-precision micro injection molding technology needs to be used, and the injection molding process needs to be finely controlled and adjusted. Only in this way, can the requirements of micro-sized plastic parts on precision and quality be met, and the harsh service conditions be met, to ensure the reliability and stability of micro-sized plastic parts.

[0003] Vibration-assisted injection molding technology is a new type of injection molding technology that applies vibration technology to injection molding. It uses mechanical vibration or ultrasonic vibration to assist injection molding, which makes the molten plastic particles more uniformly dispersed in the matrix in a molten state, thereby improving its flowability and uniformity, making the plastic more uniformly filled into the mold, avoiding defects such as insufficient filling or uneven gate position; reduce the viscosity of the molten plastic, thereby reducing the pressure and energy required to fill the mold, improving production efficiency; improve the molecular exchange of the material, improve the crystallization behavior of the material, thereby improving the physical and mechanical properties of the product. This technology can be applied to various polymer materials, including thermoplastic plastics, thermosetting plastics, rubbers and composites, etc., to manufacture various types of injection molded products, such as automobile parts, medical devices, electronic product housings, etc. However, in the field of micro injection molding, the micro injection molded products have many fine structures, which leads to the structure of the mold core of the corresponding mold being very complex. These structures include closely arranged flow channels, ejector pins, vents, etc., increasing the difficulty of mold manufacturing and injection molding process. At present, the vibration source of vibration-assisted injection molding technology is generally large, such as ultrasonic generator, voice coil motor, etc., which is difficult to integrate into the mold core of the micro injection mold. This has led to certain limitations in the application of vibration-assisted technology in the field of micro injection molding.

[0004] For example, a kind of "ultrasonic vibration and vacuum integrated micro injection mold and molding method" disclosed in Chinese patent literature, its announcement number: CN102601936, discloses a mold structure that ultrasonic transducer end face is processed into a part of cavity, but the product of this scheme production structure is simple, cannot be applied in the mold with complex mould structure. SUMMARY

[0005] In order to solve the problem that vibration-assisted technology cannot be applied to micro injection mold with complex mould structure, and the effect of vibration on the processing performance of polymer material is not ideal, the present application provides a micro injection mold with adjustable frequency and amplitude combined vibration runner structure, by increasing ultrasonic vibration and mechanical vibration components in the runner, without affecting the mould structure of the mould, the polymer melt flowing through the runner can be maximally vibrated, and the vibration angle (0°-80°), order and combination can be flexibly changed, by controlling the ultrasonic vibration power, mechanical vibration frequency and amplitude, the micro morphology of multi-component polymer in multiple scenarios can be improved, and the performance of micro injection product can be improved.

[0006] The object of the present application is achieved by the following technical solutions:

[0007] A micro injection mold with adjustable frequency and amplitude combined variable-angle vibration runner structure, comprising a movable mold plate and a fixed mold plate, further comprising a gate sleeve arranged in the fixed mold plate;

[0008] The gate sleeve comprises two oppositely arranged arc blocks, and oppositely arranged mechanical vibration blocks and ultrasonic vibration blocks between the two arc blocks; the two arc blocks are fixedly connected to the fixed mold plate; the mechanical vibration blocks and the ultrasonic vibration blocks are all multiple, the multiple mechanical vibration blocks are stacked between the two arc blocks, and the multiple ultrasonic vibration blocks are stacked between the two arc blocks; the mechanical vibration blocks, the ultrasonic vibration blocks and the two arc blocks enclose an internal area as a through-flow channel; the flow channel is a variable-angle structure, the inner surface inclination angle of the stacked mechanical vibration blocks and ultrasonic vibration blocks gradually changes from the inlet of the gate sleeve to the cavity, so that the cross-sectional area of the flow channel gradually increases;

[0009] The micro injection mold further comprises an ultrasonic transducer, an ultrasonic generator, a voice coil motor and a controller; the ultrasonic transducer is fixed on the fixed mold plate, and a probe of the ultrasonic transducer penetrates through the fixed mold plate into a through hole of the fixed mold plate where a gate bushing is arranged, and is used for being fixedly connected with the ultrasonic vibration block; the voice coil motor is connected with the controller through a wire, and the voice coil motor is fixed on the fixed mold plate, and an output shaft of the voice coil motor also penetrates through the fixed mold plate into the through hole of the fixed mold plate where the gate bushing is arranged, and is used for being fixedly connected with the mechanical vibration block; the ultrasonic generator, the ultrasonic transducer and the ultrasonic vibration block form an ultrasonic vibration unit, and the controller, the voice coil motor and the mechanical vibration block form a mechanical vibration unit.

[0010] Further, three holes are arranged on the mechanical vibration block and the ultrasonic vibration block, when the vibration block is used for applying vibration, the hole in the middle is used for being fixedly connected with the ultrasonic transducer or the voice coil motor; when the vibration block is not used for applying vibration, the vibration block is fixedly connected with the fixed mold plate through the holes on two sides.

[0011] Further, in order to provide space for the movement of the mechanical vibration block, a plurality of spring structures are arranged on a side of the mechanical vibration block close to the voice coil motor.

[0012] Further, in order to provide space for the movement of the ultrasonic vibration block, a rubber gasket is arranged on a side of the ultrasonic vibration block close to the ultrasonic transducer.

[0013] Further, the ultrasonic vibration unit applies high-frequency low-amplitude vibration to the polymer melt in the flow channel, and the mechanical vibration unit applies low-frequency high-amplitude vibration to the polymer melt in the flow channel.

[0014] The beneficial effects of the present application are as follows:

[0015] (1) The present application can effectively improve the flow performance of the polymer melt and the forming quality by applying vibration in the flow channel. Compared with the method of increasing vibration near the mold core, applying vibration in the flow channel can more accurately control the flow of the polymer melt, and effectively avoid the disadvantages of complex structure and small volume of the precision injection mold core, and avoid the influence of vibration on the mold core structure, the arrangement of the ejector pin and the like. In addition, since the volume of the flow channel is small, the fluid will pass through the flow channel, and therefore the vibration effect is more obvious.

[0016] (2) The present application can improve the quality and production efficiency of injection molded products, and has wide application prospect.

[0017] (3) The ultrasonic vibration block of the present application is a small block assembly structure, which can realize the change of vibration angle, change the vibration direction by changing the vibration position, and can self-adjust the angle, size and combination of vibration according to the type and composition of different filler / high polymer composite materials, and apply in different directions and forms to achieve the best forming effect. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a main sectional view of the micro injection mold of the adjustable frequency and amplitude combined variable angle vibration flow channel structure of the embodiment of the present application.

[0019] Figure 2 It is a schematic diagram of the fixing mode of the ultrasonic vibration block and the mechanical vibration block respectively, wherein figure (a) is a schematic diagram of the connection of the vibration block in the working state, and figure (b) is a schematic diagram of the structure of the vibration block fixed on the fixed mold plate 11 in the non-working state.

[0020] Figure 3 It is a schematic diagram of the micro injection mold observed from the direction of the flow channel inlet.

[0021] Figure 4 It is a flow chart of the use method of the micro injection mold of the embodiment of the present application.

[0022] Figure 5 It is a schematic diagram of the structure of the ultrasonic generator and the voice coil motor assembled to the vibration block at different positions on two sides.

[0023] In the figure, 1 is a movable mold fixed plate, 2 is a push plate fixed plate, 3 is a push rod, 4 is a ejector pin hole, 5 is an ejector pin, 6 is a push plate, 7 is a guide pillar, 8 is a movable mold support plate, 9 is a movable mold plate, 10 is a micro structure cavity, 11 is a fixed mold plate, 12 is an ultrasonic generator, 13 is an ultrasonic transducer, 14 is a fixed mold fixed plate, 15 is an ultrasonic vibration block, 16 is a gate bushing, 17 is a gate bushing positioning ring, 18 is a mechanical vibration block, 19 is a voice coil motor, 20 is a controller, 21 is a spring, 22 is a limit screw, 23 is a rubber washer, 24 is a flow channel, and 25 is an arc block. DETAILED DESCRIPTION

[0024] The purpose and effect of the present application will become more apparent from the following detailed description of the preferred embodiments according to the drawings, and it should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0025] The principle of the present application is: applying vibration to the flow channel structure of the micro injection mold, connecting the vibration blocks of different angles in the flow channel with the vibration assembly, combining different forms of vibration through different ways to form corresponding mechanical / ultrasonic composite vibration field, applying vibration shear field to the polymer melt, so that the molecular chain of the polymer melt is disentangled and the microstructure such as crystallization performance is changed under the applied composite vibration field.

[0026] As shown in Figure 1 The adjustable frequency amplitude combined variable angle vibration flow channel structure micro injection mold of the embodiment includes a movable mold plate 9 and a fixed mold plate 11. The movable mold plate 9 is pressed against the fixed mold plate 11 and the fixed mold plate 14 through a movable mold support plate 8, a guide column 7, a push plate 6, a ejector pin 5, a push rod 3, a movable mold fixed plate 1, and a push plate fixed plate 2. When the mold is locked, the movable mold plate 9 and the fixed mold plate 11 form a product cavity containing microstructures. Cooling pipes are arranged inside the movable mold plate 9 and the fixed mold plate 11 for temperature control of the mold, and the cooling pipes inside the movable mold plate 9 and the fixed mold plate 11 are not connected. A through hole is formed in the fixed mold plate 11, and a gate bushing 16 is installed in the through hole of the fixed mold plate 11.

[0027] As shown in Figure 1 and Figure 3 In the embodiment, the gate bushing 16 includes two oppositely arranged arc-shaped blocks 25, and a mechanically vibrating block 18 and an ultrasonic vibrating block 15 oppositely arranged between the two arc-shaped blocks 25. The two oppositely arranged arc-shaped blocks 25 are fixed to the fixed mold plate 11. The mechanically vibrating block 18 and the ultrasonic vibrating block 15 are both multiple blocks, which are stacked layer by layer between the two arc-shaped blocks 25. The mechanically vibrating block 18, the ultrasonic vibrating block 15, and the two arc-shaped blocks 25 enclose an internal region that is a through flow channel 24. From the inlet of the gate bushing 16 to the cavity, the inner surfaces of the stacked mechanically vibrating blocks 18 and ultrasonic vibrating blocks 15 gradually change in angle, so that the cross-sectional area of the flow channel 24 gradually increases, i.e., the flow channel 24 is a variable angle structure. The gate bushing 16 is axially limited by a gate bushing positioning ring 17 fixed to the fixed mold fixed plate 14.

[0028] As shown in Figure 1As shown, in this embodiment, the micro injection mold further comprises an ultrasonic transducer 13 and an ultrasonic generator 12. The ultrasonic transducer 13 is fixed on the fixed mold plate 11 by a flange structure through a screw, and is connected to the ultrasonic generator 12 through a wire. The ultrasonic transducer 13 comprises a transducer, an amplifier and a probe connected in sequence. The probe penetrates through the fixed mold plate 11 and is deeply inserted into the through hole of the fixed mold plate 11, and is connected to one of the ultrasonic vibration blocks 15 through a thread. The ultrasonic generator 12, the ultrasonic transducer 13 and the ultrasonic vibration block 15 form an ultrasonic vibration unit. The ultrasonic vibration unit can provide high-frequency low-amplitude vibration of 1-10 μm, the frequency range is between 20 kHz-40 kHz, and the maximum power can reach 1200 W. The settings of the transducer, the amplifier and the probe are adjusted to adjust the ultrasonic vibration unit. The ultrasonic vibration unit provides a given high-frequency vibration in the flow direction of the polymer melt to improve the molecular exchange of the material, improve the crystallization behavior of the material, and make the molecular chains of the polymer melt bear high-frequency vibration with small displacement, so as to dynamically disentangle and further improve the tensile orientation of the polymer melt. As shown in Figure 2 As shown, in order to provide space for the movement of the ultrasonic vibration block 15, a rubber gasket 23 is arranged on the side of the ultrasonic vibration block 15 close to the ultrasonic transducer 13.

[0029] As shown in Figure 1 As shown, in this embodiment, the micro injection mold further comprises a voice coil motor 19 and a controller 20. The voice coil motor 19 is fixed on the fixed mold plate 11, and the output shaft thereof is threadedly connected to one of the mechanical vibration blocks 18. The voice coil motor 19 is further connected to the controller 20 through a wire. The controller 20, the voice coil motor 19 and the mechanical vibration block 18 form a mechanical vibration unit, which provides low-frequency high-amplitude vibration with an amplitude of 0-5 mm and a frequency of 0-100 Hz. The mechanical vibration generated by the voice coil motor 19 is adjusted by the controller 20, and is further transmitted by the mechanical vibration block 18, so that the polymer melt follows the mechanical vibration block 18 to move back and forth when flowing through the flow channel 24, thereby providing reciprocating high-amplitude shear action in the corresponding angle, and making the molecular chains in the polymer melt bear large displacement continuous stretching motion in this direction. Similarly, as shown in Figure 2 As shown, in order to provide space for the movement of the mechanical vibration block 18, a plurality of spring structures 21 are arranged on the side of the mechanical vibration block 18 close to the voice coil motor 19.

[0030] Since the mechanical vibration blocks 18 and the ultrasonic vibration blocks 15 are both multiple, one vibration block is selected to apply vibration each time. Therefore, when vibration is applied, the selected mechanical vibration block 18 and the ultrasonic vibration block 15 are respectively screwed with the voice coil motor 19 and the probe of the ultrasonic transducer 13 through the middle screw holes to transmit the vibration generated by the vibration unit to the melt. The remaining mechanical vibration blocks 18 and the ultrasonic vibration blocks 15 are fixed on the fixed mold plate 11 through the screw holes on both sides. Since the inclination angles of the vibration blocks constituting the flow channel are different, different mechanical vibration blocks 18 and ultrasonic vibration blocks 15 can be connected to change the angle of applied vibration and combination.

[0031] As shown in Figure 4 The micro injection molding process using the micro injection molding mold with the adjustable amplitude and angle vibration flow channel structure of the present application is as follows:

[0032] 1. Select the vibration angle, size and combination according to the type and composition of the filler / polymer composite material to select the vibration mode to be superimposed, for example, select the ultrasonic vibration and mechanical vibration to trigger at the same angle on the vibration block, connect the vibration blocks corresponding to the vibration to the vibration assembly, and lock the remaining vibration blocks by the limiting screw as a part of the flow channel. Figure 1 According to the selection, the mold is assembled and installed on the injection molding machine.

[0033] 2. Dry the polymer raw material and preheat the injection molding unit of the injection molding machine.

[0034] 3. Perform injection molding to fill the microstructure cavity with the polymer through the nozzle sleeve 16 and the flow channel 24. At this time, the amplitude peak of the ultrasonic vibration can be adjusted by adjusting the driving electric signal and increasing or decreasing the amplitude rod, so that the molecular chains in the polymer melt are subjected to small displacement high frequency vibration for dynamic disentanglement. The voice coil motor 19 generates a superimposed reciprocating mechanical action in the flow direction, and the mechanical vibration amplitude peak of the piston can be controlled by adjusting the input electric signal of the motor, so that the molecular chains in the polymer melt are subjected to large displacement continuous stretching motion and small displacement high frequency vibration in the corresponding vibration direction, forcing the polymer melt molecular chains to dynamically disentangle, thereby realizing good stretching orientation of the polymer melt.

[0035] After the superimposed vibration field is applied, the polymer is cooled and shaped after a period of time, and the microstructure product with improved mechanical properties is obtained after the mold is opened. One processing process is completed, and the mold can be closed again to inject the unoriented polymer melt by the injection molding system to start the next cycle.

[0036] The present application will be described in detail below with reference to several embodiments.

[0037] Example 1

[0038] In assembling the mold, the ultrasonic transducer 13 and the voice coil motor 19 are assembled to the vibration blocks at the same position on both sides, so as to superimpose the wide-frequency amplitude vibration mode to act on the polymer.

[0039] As shown in Figure 1 When the polymer melt flows through the flow channel 24 via the injection molding machine nozzle, the excitation signals are generated to the ultrasonic generator 12 and the voice coil motor controller 19, the ultrasonic probe generates high-frequency low-amplitude vibration, and the voice coil motor 19 generates low-frequency high-amplitude vibration, and the two vibration modes are superimposed in the same normal direction to generate shear action on the melt flowing through the flow channel 24, effectively inducing the disentanglement of the polymer chain and promoting the formation of the oriented structure.

[0040] Through the above-mentioned embodiments, for the single-component polymer melt, the degree of molecular chain entanglement can be effectively reduced by superimposing the vibration field, the aggregate state structure can be directionally controlled, the melt viscosity can be effectively reduced, the melt flowability can be improved, and the melt can be more fully filled into the microstructure mold.

[0041] Example 2

[0042] In assembling the mold, the ultrasonic generator 12 and the voice coil motor 19 are assembled to the vibration blocks at different positions on both sides, and different shear actions are generated on the polymer in sequence.

[0043] As shown in Figure 5 When the polymer melt flows through the flow channel 24 via the injection molding machine nozzle, the melt first flows through the mechanical vibration block 18, the voice coil motor 19 generates low-frequency high-amplitude vibration to generate large-amplitude shear action, and the high molecular chain is induced to disentangle, and then flows through the ultrasonic vibration block 15, the ultrasonic probe generates high-frequency low-amplitude vibration to destroy the force between the polymer molecular chains, thereby reducing the viscosity of the melt, reducing the flow channel resistance, and improving the filling performance of the melt. The two vibration modes sequentially apply vibration to the melt flowing through the flow channel, induce the disentanglement of the high molecular chain, and improve the flowability of the melt.

[0044] Through the above-mentioned embodiments, for the multi-component polymer melt, the bubbles, cavities and particle agglomerates in the melt are first broken by the mechanical vibration, and then the distribution of different components of the polymer melt is adjusted by the ultrasonic vibration, thereby improving the quality and consistency of the product.

[0045] Those skilled in the art can understand that the above-mentioned is only a preferred example of the application, and is not used to limit the application, although the application is described in detail with reference to the foregoing examples, and those skilled in the art can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features. Any modification, equivalent replacement, etc. made within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A micro injection mold with a variable amplitude and variable angle vibration flow channel structure, characterized in that, The injection mold comprises a movable mold plate and a fixed mold plate, and a sprue bushing arranged in the fixed mold plate; The sprue bushing comprises two oppositely arranged arc blocks, and oppositely arranged mechanical vibration blocks and ultrasonic vibration blocks between the two arc blocks; the two arc blocks are fixedly connected to the fixed mold plate; the mechanical vibration blocks and the ultrasonic vibration blocks are both multiple, and the multiple mechanical vibration blocks are stacked between the two arc blocks layer by layer, and the multiple ultrasonic vibration blocks are stacked between the two arc blocks layer by layer; the mechanical vibration blocks, the ultrasonic vibration blocks and the two arc blocks form an internal region which is a through flow channel; the flow channel is of a variable angle structure, and the inner surfaces of the stacked mechanical vibration blocks and ultrasonic vibration blocks gradually change in inclination angle from the inlet of the sprue bushing to the cavity, so that the cross-sectional area of the flow channel gradually increases; The micro injection mold further comprises an ultrasonic transducer, an ultrasonic generator, a voice coil motor and a controller; the ultrasonic transducer is fixed to the fixed mold plate, and the probe of the ultrasonic transducer extends into the through hole of the fixed mold plate where the sprue bushing is arranged, for being fixedly connected with the ultrasonic vibration blocks; the voice coil motor is connected with the controller through wires, and the voice coil motor is fixed to the fixed mold plate, and the output shaft of the voice coil motor also extends into the through hole of the fixed mold plate where the sprue bushing is arranged, for being fixedly connected with the mechanical vibration blocks; the ultrasonic generator, the ultrasonic transducer and the ultrasonic vibration blocks form an ultrasonic vibration unit, and the controller, the voice coil motor and the mechanical vibration blocks form a mechanical vibration unit; Three holes are arranged on the mechanical vibration blocks and the ultrasonic vibration blocks, and when the vibration blocks are used to apply vibration, the middle hole is used to be fixedly connected with the ultrasonic transducer or the voice coil motor; when the vibration blocks are not used to apply vibration, the vibration blocks are fixedly connected with the fixed mold plate through the two side holes.

2. The micro injection mold with adjustable frequency and amplitude combination variable angle vibration flow channel structure according to claim 1, characterized in that, In order to provide space for the movement of the mechanical vibration blocks, a plurality of spring structures are arranged on the side of the mechanical vibration blocks close to the voice coil motor.

3. The micro injection mold with adjustable frequency amplitude combination variable angle vibration flow channel structure according to claim 1, characterized in that, In order to provide space for the movement of the ultrasonic vibration blocks, a rubber gasket is arranged on the side of the ultrasonic vibration blocks close to the ultrasonic transducer.

4. The micro injection mold with adjustable amplitude-combined variable-angle vibration flow channel structure according to claim 1, characterized in that, The ultrasonic vibration unit applies high-frequency low-amplitude vibration to the polymer melt in the flow channel, and the mechanical vibration unit applies low-frequency high-amplitude vibration to the polymer melt in the flow channel.

Images