Double-injection molding system

Abstract

The utility model discloses a double-injection molding system, which is mainly characterized in that a material quantity control device is arranged between each injection device and a feeding device, each injection device is provided with an injection pipe with an injection port and a needle valve unit arranged in the injection pipe, each material quantity control device is provided with a control unit and a stop unit, and the needle valve unit is provided with a needle valve. The needle valve unit and the stopping unit are respectively controlled by the control unit, and after the screw rod of the feeding device mixes the material and the supercritical fluid into a mixture, the stopping unit and the needle valve unit are linked through the control unit so as to control the communication state between the feeding device and the ejection pipe and control the blocking degree of the ejection opening; therefore, the feeding amount and the ejection amount of the mixture are controlled, the defect of incomplete filling caused by uneven discharging is avoided, and the subsequent forming quality and the yield are effectively improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of injection molding systems, specifically to a kind of double-shot injection molding system. BACKGROUND

[0002] Double-shot injection molding technology is a common and very mature process technology, which can injection mold two different materials into a single object, producing plastic products with different colors, materials or textures. It not only can form relatively complex and more diversified products, but also can be used for injection molding individual objects, thereby improving processing efficiency. Compared with single-shot injection molding technology, it can reduce processing procedures, save time and cost spent on subsequent assembly, reduce waste rate during production, and thus improve production efficiency and economic benefits. Therefore, it is widely used in various fields such as electronic products, automobile parts, medical devices, sports equipment and various household items.

[0003] The existing double-shot injection molding system includes two injection devices, and a feeding device and a mold clamping device connected with the injection devices respectively. The feeding device has a feeding pipe, a hopper and a supply unit connected with the feeding pipe respectively, and a screw installed in the feeding pipe. Each injection device has an injection pipe with a feeding port and an injection port, and a push unit in the injection pipe. The mold clamping device has an upper mold and a lower mold arranged correspondingly, and a ejector unit connected with the lower mold. The upper mold is connected with the injection port of each injection device. When the ejector unit pushes the lower mold towards the upper mold, the upper mold and the lower mold are tightly closed to form a molding space.

[0004] Continuing the foregoing, when using the double-shot injection molding system, the material stored in the hopper is first introduced into the feeding pipe, and a foaming agent is input into the feeding pipe through the supply unit. During the rotation of the screw, the material and the foaming agent are fully mixed into a mixture. The mixture is pushed into the injection pipes of the injection devices by the screw. The ejector unit pushes the lower mold towards the upper mold, so that the upper mold and the lower mold are closed to form the molding space. Then the mixture is extruded by the push unit and injected into the molding space, thereby forming an object.

[0005] However, it is found that the screw is provided with a plurality of threads on the surface thereof to push the mixture forward by rotating the threads, and the threads must be continuously spirally inclined along the surface of the screw, so that the left and right sides of the same thread are not in the same position when viewed from the end face, that is, a front and back difference is generated, which leads to different feeding amounts of the left and right sides of the threads of the screw, the amount of the mixture carried on the front side is less than that on the rear side, the feeding amount of the mixture received by the injection device is different, and the phenomena of uneven discharge and incomplete filling are generated, thereby increasing the defective rate of subsequent injection molding. In addition, the connection channel between the injection device and the mold clamping device is bent, which is more likely to cause pressure changes of the mixture during transportation and unevenly enter the molding space, thereby leading to relatively unstable molding quality, which needs to be improved. Content of the utility model

[0006] Therefore, the purpose of the present utility model is to provide a double-injection molding system which can accurately control the feeding and subsequent injection amount of the mixture, effectively avoid the defects of uneven discharge and incomplete filling, and thereby improve the subsequent molding quality and yield.

[0007] Therefore, the purpose of the present utility model is to provide a double-injection molding system which can accurately control the feeding and subsequent injection amount of the mixture, effectively avoid the defects of uneven discharge and incomplete filling, and thereby improve the subsequent molding quality and yield.

[0008] As a further improvement of the present utility model, each of the material amount control devices is provided with a metering unit connected with the control unit.

[0009] As a further improvement of the present utility model, the mold clamping device is connected with an air inlet and outlet device to maintain the constant pressure state and stable foaming in the molding space.

[0010] Compared with the prior art, the utility model has the beneficial effects that:

[0011] The utility model can adjust and precisely control the feeding operation of different shooting devices and the shooting amount of the mixture shot subsequently, effectively avoid the lack of incomplete filling caused by uneven discharging, and effectively improve the subsequent molding quality and yield. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 It is the schematic diagram of a preferred embodiment of the utility model.

[0013] Figures 2-3 It is the feeding schematic diagram of the preferred embodiment.

[0014] Figures 4-5 It is the stop feeding schematic diagram of the preferred embodiment.

[0015] Figure 6 It is another schematic diagram of the preferred embodiment.

[0016] Figure 7 It is the shooting schematic diagram of the preferred embodiment.

[0017] Figure 8 It is the stop shooting schematic diagram of the preferred embodiment.

[0018] SYMBOL EXPLANATION:

[0019] (The utility model)

[0020] 3: double shooting shooting system

[0021] 31: feeding device

[0022] 32: shooting device

[0023] 33: clamp mold device

[0024] 34: material amount control device

[0025] 35: air inlet and exhaust device

[0026] 311: hopper

[0027] 312: feeding pipe

[0028] 313: supply unit

[0029] 314: screw

[0030] 315: feeding channel

[0031] 321: shooting pipe

[0032] 322: feeding port

[0033] 323: shooting port

[0034] 324 needle valve unit

[0035] 331 upper mold

[0036] 332 lower mold

[0037] 333 top mold unit

[0038] 334 molding space

[0039] 341 control unit

[0040] 342 stop unit

[0041] 343 metering unit

[0042] A material

[0043] B supercritical fluid

[0044] C mixture DETAILED DESCRIPTION

[0045] The foregoing and other technical contents, features and effects of the present application will be apparent from the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings.

[0046] Referring to Figure 1 , Figure 2 and Figure 6 , a preferred embodiment of the dual-shot injection molding system 3 includes a feeding device 31, two injection devices 32 respectively connected to the feeding device 31, and a mold clamping device 33 connected to the plurality of injection devices 32. The plurality of injection devices 32 are independently arranged from each other, and each injection device 32 is provided with a material amount control device 34 between the injection device 32 and the feeding device 31. In this embodiment, the mold clamping device 33 is connected to an air feeding and exhausting device 35. The feeding device 31 has a hopper 311 storing a material A, a feeding pipe 312 connected to the hopper 311, a supply unit 313 connected to the feeding pipe 312, and a screw 314 installed in the feeding pipe 312. The feeding pipe 312 is provided with a feeding passage 315 between the feeding pipe 312 and each injection device 32. In addition, the supply unit 313 is used to input a supercritical fluid B into the feeding pipe 312 as a physical foaming agent.

[0047] Referring to Figure 2 , Figure 3 and Figure 6As shown, each of the injection devices 32 has a hollow injection tube 321, an inlet 322 connected to the feeding channel 315, an injection outlet 323 formed on the injection tube 321, and a needle valve unit 324 installed in the injection tube 321, and the injection tube 321 is arranged in a straight line. In addition, the mold clamping device 33 has an upper mold 331 connected to the injection outlet 323 of each of the injection devices 32, a lower mold 332 arranged in correspondence with the upper mold 331, and a top mold unit 333 connected to the lower mold 332, and the top mold unit 333 can push the lower mold 332 towards the upper mold 331 to tightly close the upper mold 331 and the lower mold 332 to form a molding space 334. In this embodiment, the mold clamping device 33 has two independent molding spaces 334, and the plurality of molding spaces 334 are preferably shoe-shaped.

[0048] As shown, Figure 2 and Figure 3 As shown, each of the material amount control devices 34 has a control unit 341, a stop unit 342 driven by the control unit 341, and a metering unit 343 connected to the control unit 341. The stop unit 342 is arranged between the inlet 322 of the corresponding injection device 32 and the corresponding feeding channel 315. In this embodiment, the control unit 341 can control the stop unit 342 to extend and retract to control the communication state between the feeding channel 315 and the corresponding injection tube 3221 through the stop unit 342. In addition, the metering unit 343 is arranged in the injection tube 321 to detect the feeding amount and injection amount of the mixture C.

[0049] As shown, Figure 2 , Figure 3 and Figure 6 As shown, when the double-injection molding system 3 is used, the material A is first introduced into the feeding tube 312 from the hopper 311, and at the same time, the supercritical fluid B is introduced into the feeding tube 312 from the supply unit 313. During the rotation of the screw 314, the material A and the supercritical fluid B are uniformly mixed into the mixture C, and the mixture C is driven by the screw 314 to move towards the plurality of feeding channels 315. At this time, the control unit 341 drives the stop unit 342 to shorten to make the injection tube 321 and the feeding channel 315 communicate with each other, so that the mixture C is input into the injection tube 321 through the inlet 322, and the needle valve unit 324 blocks the injection outlet 323, and the metering unit 343 detects the feeding amount of the mixture C input into the injection tube 321 and returns the feeding amount information to the control unit 341. As shown, Figure 4 and Figure 5As shown, when the injection tube 321 is filled with enough mixture C, the control unit 341 drives the stop unit 342 to extend, so that the injection tube 321 is not communicated with the feeding passage 315, to stop the feeding operation of the mixture C.

[0050] Referring to Figure 4 and Figure 7 As shown, then the top die unit 333 pushes the lower die 332, so that the lower die 332 and the upper die 331 are closed to form a plurality of the molding spaces 334, and then the control unit 341 drives the needle valve unit 324 to move away from the injection outlet 323, so that the mixture C enters the corresponding molding space 334 in a straight line through the injection outlet 323, thereby avoiding the mixture C being blocked during the conveying process, and ensuring that the conveying pressure is uniform, while the metering unit 343 detects the injection amount of the mixture C input into the molding space 334, and returns the injection amount information to the control unit 341, referring to Figure 8 As shown, when the molding space 334 is filled with enough mixture C, the control unit 341 drives the needle valve unit 324 to block the injection outlet 323, to stop the injection operation of the mixture C, of course, the control unit 341 can also control the degree of the needle valve unit 324 blocking the injection outlet 323 according to the injection amount information, thereby controlling the injection amount and injection speed of the mixture C, to facilitate precise control and adjustment of the injection amount of the mixture C injected by each injection device 32 to the die clamping device 33, and to ensure that the molding space 334 receives enough amount of the mixture C, and to solve the lack of uniformity and incomplete filling caused by the screw 314 feeding process.

[0051] As described above, the exhaust device 35 also extracts the gas in the molding space 334, so that the mixture C in the molding space 334 is stably foamed and respectively molded into different objects (not shown in the figure), thereby effectively improving the molding quality and yield of the objects, and when the mixture C is not injected into the molding space 334, the exhaust device 35 inputs gas into the molding space 334 to maintain a constant pressure state, of course, the injection device 32 can also be filled with different mixtures C according to actual use, or the control unit 341 can drive the needle valve unit 324 to inject the filled mixture C into the corresponding molding space 334 at different times, to improve the variability of use.

[0052] In summary, the double-injection molding system can control and adjust the feeding amount and injection amount of the mixture accurately by controlling the corresponding stop unit and needle valve unit through the control unit of the material amount control device, so as to avoid incomplete filling caused by uneven discharging and the like, and effectively improve the subsequent molding quality and yield.

[0053] The above description is only a preferred embodiment of the present application, and cannot limit the scope of the present application. Any simple equivalent changes and modifications made according to the scope of the present application and the content of the present application should still be within the scope of the present application.

Claims

1. A bi-injection molding system comprising a feeding device, a plurality of injection devices each connected to the feeding device, and a clamping device connected to the plurality of injection devices; wherein, The feeding device has a hopper for storing material, a feeding pipe connected to the hopper, a feeding unit connected to the feeding pipe, and a screw arranged in the feeding pipe. Each of the injection devices has an injection pipe, and a feeding port and an injection port respectively arranged in the injection pipe. The mold clamping device has an upper mold connected to the injection port of each of the injection devices, a lower mold opposite to the upper mold, a ejector unit connected to the lower mold, and a molding space formed when the upper mold and the lower mold are closed. The feeding unit is used to input a supercritical fluid as a physical foaming agent. The supercritical fluid and the material are mixed by the screw in the feeding pipe to form a mixture. Each of the injection pipes is arranged in a straight line, and a needle valve unit is arranged in the injection pipe to control the injection amount of the mixture in the molding space. Each of the injection devices is provided with a quantity control device. The quantity control device has a control unit connected to the needle valve unit, and a stop unit driven by the control unit to control the feeding operation and the injection operation of the mixture. Each of the quantity control devices has a metering unit connected to the control unit.

2. The bi-injection molding system of claim 1, wherein, The mold clamping device is connected to an air supply and exhaust device to maintain a constant pressure in the molding space and stable foaming.

3. The bi-injection molding system of claim 1, wherein, ​

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