Multi-layer injection molding device for thick-walled plastic parts

Abstract

The present invention provides a multi-layer injection molding device for thick-walled plastic parts, which is used for injection molding thick-walled plastic parts divided into 2n + 1 layers, and includes: a fixed mold and a movable mold; 2n fixed stations are arranged along the circumferential direction of the fixed mold, and 2n movable stations are arranged along the circumferential direction of the movable mold; n is a natural number; the 2n fixed stations and the 2n movable stations form 2n injection molding stations, and a moving component is arranged on the movable mold, and the moving component can move the workpiece formed by injection molding at the previous injection molding station to the next injection molding station; the first injection molding station injects and forms the first layer structure located in the central area of the thick-walled plastic part. The device of the present invention adopts multi-layer injection molding, first injects the core of the product, and then injects and forms the two sides of the product in multiple layers in a divided manner, so that the resin of each layer can be cooled most sufficiently, and the problem of long molding cycle is solved.

Description

Technical Field

[0001] The present invention relates to the field of injection molding technology, and specifically, to a multi-layer injection molding device for thick-walled plastic parts, especially a 2n + 1 layer high-efficiency and high-quality injection molding device for thick-walled lenses. Background Art

[0002] The typical thickness of the automotive lighting high and low beam module lens is usually 25 mm or even more than 30 mm. When the material of the lens is resin, the commonly used polymer materials are PC or PMMA. The thick lens formed by polymer injection molding faces two key technical problems: one is the extremely long cooling time, and the other is the shrinkage of the polymer during the cooling process. In the case of a thick lens, the extremely long cooling time extremely affects the production efficiency. For mass-produced automobiles, a long cycle means low efficiency, which means more investment in molds and forming equipment. For lenses with strict light distribution requirements, the continuous shrinkage of the polymer highly affects the accuracy of light distribution. Summary of the Invention

[0003] Aiming at the defects in the prior art, the purpose of the present invention is to provide a multi-layer injection molding device for thick-walled plastic parts with the name as above.

[0004] A multi-layer injection molding device for thick-walled plastic parts according to the present invention, which is used for injection molding a thick-walled plastic part divided into 2n + 1 layers, includes: a fixed mold and a movable mold;

[0005] There are 2n fixed stations circumferentially distributed on the fixed mold, and 2n movable stations are arranged circumferentially on the movable mold; n is a natural number;

[0006] The 2n fixed stations and the 2n movable stations form 2n injection molding stations, and a moving component is arranged on the movable mold, and the moving component can move the workpiece formed by injection molding at the previous injection molding station to the next injection molding station;

[0007] The first injection molding station injects and forms the first layer structure located in the central area of the thick-walled plastic part;

[0008] When n is equal to 1, the second injection molding station injects and forms the second layer structure and the third layer structure respectively located on both sides of the first layer structure;

[0009] When n is greater than 1, the second injection molding station to the 2n - 1th injection molding station alternately inject and form the second layer structure to the 2n - 1th layer structure on both sides of the first layer structure in sequence, and the 2nth injection molding station injects and forms the 2nth layer structure and the 2n + 1th layer structure;

[0010] For the second-layer structure to the (2n + 1)-layer structure, the cavities for forming the even-layer structures are located on the movable mold, and the cavities for forming the odd-layer structures are located on the fixed mold.

[0011] Preferably, when n equals 1, the first fixed station and the first movable station perform injection molding to form the first-layer structure located in the central region of the thick-walled plastic part;

[0012] The second fixed station and the second movable station perform injection molding to form the second-layer structure connected to one side of the first-layer structure, and perform injection molding to form the third-layer structure connected to the other side of the first-layer structure.

[0013] Preferably, when n equals 2, the first fixed station and the first movable station perform injection molding to form the first-layer structure located in the central region of the thick-walled plastic part;

[0014] The second fixed station and the second movable station perform injection molding to form the second-layer structure connected to one side of the first-layer structure;

[0015] The third fixed station and the third movable station perform injection molding to form the third-layer structure connected to the other side of the first-layer structure;

[0016] The fourth fixed station and the fourth movable station perform injection molding to form the fourth-layer structure covering the second-layer structure, and perform injection molding to form the fifth-layer structure covering the third-layer structure.

[0017] Preferably, when n is greater than 2, the first fixed station and the first movable station perform injection molding to form the first-layer structure located in the central region of the thick-walled plastic part;

[0018] The second fixed station and the second movable station perform injection molding to form the second-layer structure connected to one side of the first-layer structure;

[0019] The third fixed station and the third movable station perform injection molding to form the third-layer structure connected to the other side of the first-layer structure;

[0020] The mth fixed station and the mth movable station perform injection molding to form the mth layer structure covering the (m - 2)th layer structure; the (m + 1)th fixed station and the (m + 1)th movable station perform injection molding to form the (m + 1)th layer structure covering the (m - 1)th layer structure; m is an even number greater than or equal to 4 and less than 2n;

[0021] The 2nth fixed station and the 2nth movable station perform injection molding to form the 2nth layer structure covering the (2n - 2)th layer structure, and perform injection molding to form the (2n + 1)th layer structure covering the (2n - 1)th layer structure.

[0022] Preferably, the cavity for forming the second layer structure is located on the movable working position; the cavity for forming the third layer structure is located on the fixed working position;

[0023] The cavity for forming the m-th layer structure is located on the movable working position; the cavity for forming the (m + 1)-th layer structure is located on the fixed working position;

[0024] The cavity for forming the 2n-th layer structure is located on the movable working position, and the cavity for forming the (2n + 1)-th layer structure is located on the fixed working position.

[0025] Preferably, the moving component includes: a driving component and a movable-side built-in rotating arm;

[0026] The driving component and the movable-side built-in rotating arm are located within the area surrounded by 2n movable working positions, and the driving component drives the movable-side built-in rotating arm to rotate;

[0027] One end of the movable-side built-in rotating arm is connected to the driving component, and the other end of the movable-side built-in rotating arm can move the workpiece formed by the previous injection molding station to the next injection molding station.

[0028] Preferably, when the movable-side built-in rotating arm reaches the first fixed working position and the first movable working position, the other end of the movable-side built-in rotating arm can be located within the injection cavity formed by the first fixed working position and the first movable working position;

[0029] The first layer structure formed by injection molding at the first fixed working position and the first movable working position can be fixed on the movable-side built-in rotating arm.

[0030] Preferably, a pin is provided at the other end of the movable-side built-in rotating arm, and the pin is used to fix the first layer structure;

[0031] And / or, the heat of the first layer structure can be transferred out through the movable-side built-in rotating arm.

[0032] Preferably, the injection runner for injection molding the first layer structure is the first runner;

[0033] The injection runner for injection molding the (j + 1)-th layer structure is the (j + 1)-th runner, and the injection runner for injection molding the (j + 2)-th layer structure is the (j + 2)-th runner. The (j + 1)-th runner and the (j + 2)-th runner are respectively arranged on both sides of the first runner. The (j + 1)-th runner is located on the movable side, and the (j + 2)-th runner is located on the fixed side; j is an odd number greater than or equal to 1 and less than 2n + 1;

[0034] All the even-numbered flow channels are arranged in one or more layers on the movable side of the first flow channel. Each layer contains at least two even-numbered flow channels. The multiple even-numbered flow channels in each layer are arranged along the width direction of the first flow channel. The width of the first flow channel can cover the widths of the multiple even-numbered flow channels in each layer. When arranged in multiple layers, the multiple layers of even-numbered flow channels are arranged in sequence along the movable side direction.

[0035] All the odd-numbered flow channels are arranged in one or more layers on the fixed side of the first flow channel. Each layer contains at least two odd-numbered flow channels. The multiple odd-numbered flow channels in each layer are arranged along the width direction of the first flow channel. The width of the first flow channel can cover the widths of the multiple odd-numbered flow channels in each layer. When arranged in multiple layers, the multiple layers of odd-numbered flow channels are arranged in sequence along the fixed side direction.

[0036] Preferably, the width and thickness of the first flow channel are the largest among all the flow channels.

[0037] And / or, the multiple flow channels in each layer are arranged in sequence from both sides to the center along the width direction of the first flow channel.

[0038] And / or, when n is odd, the number of flow channels arranged in each layer is odd.

[0039] When n is even and its factors do not include odd numbers greater than 1, the number of flow channels arranged in each layer is even. When n is even and its factors include odd numbers greater than 1, the number of flow channels arranged in each layer is even or odd.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] 1. The present invention can realize the multi-layer injection molding of thick-walled plastic parts. First, the first fixed station and the first movable station are used to form the first layer structure in the central area of the thick-walled plastic part, and then the subsequent fixed stations and movable stations are alternately used to form multiple layers of structures on both sides of the first layer structure in sequence, thereby realizing the layered injection molding of thick-walled plastic parts, which can greatly reduce the injection molding cycle of thick-walled plastic parts. Taking the product with a wall thickness of 25 mm mentioned above as an example, when divided into 7 layers, its forming cycle can be reduced to one-eighth to one-twelfth of the cycle required for single-layer injection molding. At the same time, the present invention optimizes the setting method of the flow channels, greatly improving the product quality of layered injection molding, achieving the simultaneous improvement of efficiency and quality.

[0042] 2. Through layered injection molding, the present invention forms the light-emitting surface of the lens at the last station. The existing light-emitting surface of the lens usually requires processing complex and expensive micro-structured patterns on the injection-molded product. The present invention only forms the last layer on the front and back of the product at the last station, so only an optical micro-structured insert needs to be set at the last station.

[0043] 3. By ingeniously dividing the injection levels of the thick-walled lens and selecting the injection sequence that best conforms to the law of heat transfer, the present invention achieves the goal of low equipment investment and high-efficiency production of high-quality lenses. Both PC and PMMA are poor conductors of heat. The thermal conductivity of typical die steel is approximately 29 w / m2C. Generally speaking, the thermal conductivity of plastic PMMA and PC is no higher than 0.29 w / m2C, which is 100 times that of the latter. Only by allowing the injected resin to come into more contact with the steel can the heat of the plastic be discharged more quickly. The present invention first injects the core part of the product to fully cool the core part of the product first, and then sequentially stacks high-temperature resin on the formed part on the front or back of the formed part. This way, the product formed by the previous injection molding can still maintain contact with the steel on one side of the product in the 2nd to 5th stations, continuously taking out the heat of the product. One side of the newly injection-molded part will continuously contact the die steel in the next station, continuously taking out the heat of the product.

[0044] 4. Due to the optical requirements of the lens, there are extremely high requirements for the shape accuracy of the light incident surface and the light exit surface. Through ingenious design, the present invention places the two surfaces with the highest requirements at the last station for forming. At this time, most of the core material of the lens has been fully cooled, and the resin shrinkage has also been relatively fully compensated during the forming of the first layer. On this basis, the 2nd to 2n + 1st layers are sequentially injection-molded in layers, preferably injecting the 2nth and 2n + 1st layers simultaneously. The shrinkage of the resin injected in the previous layer will also be compensated during the injection and pressure holding of the next layer. This makes the forming process stronger, with strong anti-interference ability of the forming process, maximized forming window, and at the same time forming the light incident surface and the light exit surface of the product, converting the thick-wall injection molding into general thin-wall injection molding, greatly improving the shape accuracy of the optical lens. Even if it is necessary to adjust the cavity shape of the light incident surface and the light exit surface due to certain reasons, only the corresponding inserts at the last station need to be adjusted.

[0045] 5. Through multi-layer injection molding, the present invention first injects the core part of the product and then injects the two sides of the product in multiple layers in a layered manner, allowing each layer of resin to be fully cooled, thus solving the problem of long forming cycle. Through multi-layer injection molding, the next layer is injected on the basis of the part of the product that has been fully cooled in the front, so that the shrinkage generated by the previous layer of the product is compensated during the injection of the next layer. Through the injection compensation of multiple stations, the lens shape deviation caused by the natural shrinkage of the resin can be minimized. Description of the Drawings

[0046] By reading the detailed description of the non-restrictive embodiments with reference to the following drawings, other features, objectives, and advantages of the present invention will become more obvious:

[0047] Figure 1 Schematic structural diagram highlighting the fixed stations on the fixed mold;

[0048] Figure 2 Schematic structural diagram highlighting the workable position on the movable mold;

[0049] Figure 3 Schematic structural diagram highlighting the swing arm on the movable mold;

[0050] Figure 4 Schematic structural diagram highlighting the rotation direction of the swing arm;

[0051] Figure 5 Schematic diagram highlighting the formation of the first layer structure;

[0052] Figure 6 Schematic diagram highlighting the formation of the second layer structure;

[0053] Figure 7 Schematic diagram highlighting the formation of the third layer structure;

[0054] Figure 8 Schematic diagram highlighting the formation of the fourth layer structure;

[0055] Figure 9 Schematic diagram highlighting the formation of the fifth layer structure;

[0056] Figure 10 Schematic diagram highlighting the formation of the sixth layer structure and the seventh layer structure;

[0057] Figure 11 Schematic structural diagram highlighting the workable position;

[0058] Figure 12 Schematic three-dimensional structural diagram of the thick-walled plastic part;

[0059] Figure 13 Schematic plan structural diagram of the thick-walled plastic part;

[0060] Figure 14 For Figure 13 Schematic sectional structural diagram along lines B-B and A-A;

[0061] Figure 15 Schematic three-dimensional structural diagram of the thick-walled plastic part driving the injection molding structure in the runner;

[0062] Figure 16 Schematic plan structural diagram of the thick-walled plastic part driving the injection molding structure in the runner;

[0063] Figure 17 For Figure 16 Schematic sectional structural diagram along line C-C;

[0064] Figure 18 For Figure 16 Schematic sectional structural diagram along line D-D;

[0065] Figure 19 is Figure 16 Schematic cross-sectional structure diagram along line E-E;

[0066] Figure 20 is Figure 16 Schematic cross-sectional structure diagram along line F-F;

[0067] Figure 21 Schematic distribution diagram of the runner injection molding structure with every three runners as one layer;

[0068] Figure 22 Schematic distribution diagram of the runner injection molding structure with every two runners as one layer;

[0069] Figure 23 Schematic injection molding process diagram;

[0070] Figure 24 Schematic flow chart of the steps of the multi-layer injection molding method for thick-walled plastic parts;

[0071] Figure 25 Schematic structure diagram showing the thickness h of each layer structure;

[0072] Figure 26 Schematic diagram of simultaneously injecting the second layer structure and the third layer structure.

[0073] The figure shows:

[0074] Specific embodiments

[0075] The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several changes and improvements can still be made. These all belong to the protection scope of the present invention.

[0076] Example 1:

[0077] Such as Figures 1 to 26As shown in the figure, this embodiment provides a multi-layer injection molding device for thick-walled plastic parts, which is used to injection mold thick-walled plastic parts divided into 2n + 1 layers, including: a fixed mold 1 and a movable mold 2; 2n fixed stations are arranged along the circumferential direction of the fixed mold 1, and 2n movable stations are arranged along the circumferential direction of the movable mold 2; n is a natural number; the 2n fixed stations and the 2n movable stations form 2n injection molding stations, and a moving component is arranged on the movable mold 2, and the moving component can move the workpiece injection molded at the previous injection molding station to the next injection molding station; the first injection molding station injection molds the first layer structure located in the central area of the thick-walled plastic part; when n is equal to 1, the second injection molding station injection molds the second layer structure and the third layer structure respectively located on both sides of the first layer structure; when n is greater than 1, the second injection molding station to the 2n - 1th injection molding station alternately inject and form the second layer structure to the 2n - 1th layer structure on both sides of the first layer structure in sequence, and the 2nth injection molding station injection molds the 2nth layer structure and the 2n + 1th layer structure; for the second layer structure to the 2n + 1th layer structure, the cavities for forming the even layer structures are located on the movable mold 2, and the cavities for forming the odd layer structures are located on the fixed mold 1.

[0078] The moving component includes: a driving component and a movable-side built-in rotating arm 3; the driving component and the movable-side built-in rotating arm 3 are located in the area surrounded by the 2n movable stations, and the driving component drives the movable-side built-in rotating arm 3 to rotate; one end of the movable-side built-in rotating arm 3 is connected to the driving component, and the other end of the movable-side built-in rotating arm 3 can move the workpiece injection molded at the previous injection molding station to the next injection molding station.

[0079] When the movable-side built-in rotating arm 3 reaches the first fixed station and the first movable station, the other end of the movable-side built-in rotating arm 3 can be located in the injection cavity formed by the first fixed station and the first movable station; the first layer structure injection molded by the first fixed station and the first movable station can be fixed on the movable-side built-in rotating arm 3. A pin is arranged at the other end of the movable-side built-in rotating arm 3, and the pin is used to fix the first layer structure; the heat of the first layer structure can be transferred out through the movable-side built-in rotating arm 3.

[0080] When n is equal to 1, the first fixed station and the first movable station injection mold the first layer structure located in the central area of the thick-walled plastic part; the second fixed station and the second movable station injection mold the second layer structure connected to one side of the first layer structure, and injection mold the third layer structure connected to the other side of the first layer structure.

[0081] When n is equal to 2, the first fixed working position and the first movable working position perform injection molding to form the first layer structure located in the central region of the thick-walled plastic part; the second fixed working position and the second movable working position perform injection molding to form the second layer structure connected to one side of the first layer structure; the third fixed working position and the third movable working position perform injection molding to form the third layer structure connected to the other side of the first layer structure; the fourth fixed working position and the fourth movable working position perform injection molding to form the fourth layer structure covering the second layer structure, and perform injection molding to form the fifth layer structure covering the third layer structure.

[0082] When n is greater than 2, the first fixed working position and the first movable working position perform injection molding to form the first layer structure located in the central region of the thick-walled plastic part; the second fixed working position and the second movable working position perform injection molding to form the second layer structure connected to one side of the first layer structure; the third fixed working position and the third movable working position perform injection molding to form the third layer structure connected to the other side of the first layer structure; the m-th fixed working position and the m-th movable working position perform injection molding to form the m-th layer structure covering the (m - 2)-th layer structure; the (m + 1)-th fixed working position and the (m + 1)-th movable working position perform injection molding to form the (m + 1)-th layer structure covering the (m - 1)-th layer structure; m is an even number greater than or equal to 4 and less than 2n; the 2n-th fixed working position and the 2n-th movable working position perform injection molding to form the 2n-th layer structure covering the (2n - 2)-th layer structure, and perform injection molding to form the (2n + 1)-th layer structure covering the (2n - 1)-th layer structure.

[0083] The cavity for forming the second layer structure is located on the movable working position; the cavity for forming the third layer structure is located on the fixed working position; the cavity for forming the m-th layer structure is located on the movable working position; the cavity for forming the (m + 1)-th layer structure is located on the fixed working position; the cavity for forming the 2n-th layer structure is located on the movable working position, and the cavity for forming the (2n + 1)-th layer structure is located on the fixed working position.

[0084] The injection runner for injection molding the first-layer structure is the first runner; the injection runner for injection molding the (j + 1)-th layer structure is the (j + 1)-th runner, and the injection runner for injection molding the (j + 2)-th layer structure is the (j + 2)-th runner. The (j + 1)-th runner and the (j + 2)-th runner are respectively arranged on both sides of the first runner. The (j + 1)-th runner is located on the movable side, and the (j + 2)-th runner is located on the fixed side; j is an odd number greater than or equal to 1 and less than 2n + 1. All even runners are arranged in one or more layers on the movable side of the first runner. Each layer contains at least two even runners, and the multiple even runners in each layer are arranged along the width direction of the first runner. The width of the first runner can cover the widths of the multiple even runners in each layer. When arranged in multiple layers, the multiple layers of even runners are arranged in sequence along the movable side direction. All odd runners are arranged in one or more layers on the fixed side of the first runner. Each layer contains at least two odd runners, and the multiple odd runners in each layer are arranged along the width direction of the first runner. The width of the first runner can cover the widths of the multiple odd runners in each layer. When arranged in multiple layers, the multiple layers of odd runners are arranged in sequence along the fixed side direction.

[0085] The width and thickness of the first runner are the largest among all the runners. The multiple runners in each layer are arranged in sequence from both sides to the center along the width direction of the first runner;

[0086] When n is odd, the number of runners arranged in each layer is odd; when n is even and its factors do not include odd numbers greater than 1, then the number of runners arranged in each layer is even; when n is even and its factors include odd numbers greater than 1, then the number of runners arranged in each layer is even or odd.

[0087] In this embodiment, through 2n stations, the injection molding of the thick-walled plastic part in 2n + 1 layers is completed.

[0088] In this embodiment, n is 3. There are 6 fixed stations distributed along the circumferential direction on the fixed mold 1, and 6 movable stations are arranged along the circumferential direction on the movable mold 2. m is an even number greater than or equal to 4 and less than 2n, so m is 4.

[0089] When m is 4, the fourth fixed station and the fourth movable station injection mold the fourth layer structure connected to the second layer structure; the fifth fixed station and the fifth movable station injection mold the fifth layer structure connected to the third layer structure.

[0090] The sixth fixed station and the sixth movable station injection mold the sixth layer structure and the seventh layer structure respectively connected to the fourth layer structure and the fifth layer structure.

[0091] In other embodiments, if n is 4, then m is 4 and 6 in sequence; if n is 5, then m is 4, 6, and 8 in sequence; if n is 6, then m is 4, 6, 8, and 10 in sequence, and so on.

[0092] A fixed working station and a corresponding movable working station form an injection molding station, and a total of 2n injection molding stations are formed, namely the first injection molding station, the second injection molding station,..., the (2n - 1)-th injection molding station, and the 2n-th injection molding station.

[0093] In this embodiment, the cavity for forming the first layer structure is located on the fixed working station of the first injection molding station, and the cavity for forming the second layer structure is located on the movable working station of the second injection molding station; the cavity for forming the third layer structure is located on the fixed working station of the third injection molding station; the cavity for forming the fourth layer structure is located on the movable working station of the fourth injection molding station; the cavity for forming the fifth layer structure is located on the fixed working station of the fifth injection molding station; the cavity for forming the sixth layer structure is located on the movable working station of the sixth injection molding station, and the cavity for forming the seventh layer structure is located on the fixed working station of the seventh injection molding station.

[0094] The cavities for forming even-layer structures are on the movable working stations of their corresponding injection molding stations, and the cavities for forming odd-layer structures are on the fixed working stations of their corresponding injection molding stations.

[0095] In other embodiments, if n is 4, the cavity for forming the eighth layer structure is located on the movable working station of the eighth injection molding station, and the cavity for forming the ninth layer structure is located on the fixed working station of the ninth injection molding station; if n is 5, the cavity for forming the tenth layer structure is located on the movable working station of the tenth injection molding station, and the cavity for forming the eleventh layer structure is located on the fixed working station of the eleventh injection molding station; if n is 6, the cavity for forming the twelfth layer structure is located on the movable working station of the twelfth injection molding station, and the cavity for forming the thirteenth layer structure is located on the fixed working station of the twelfth injection molding station, and so on.

[0096] A plurality of movable-side built-in rotating arms 3 are sequentially arranged along the circumferential direction, and each movable-side built-in rotating arm 3 can sequentially move to the first injection molding station, the second injection molding station,..., the (2n - 1)-th injection molding station, and the 2n-th injection molding station.

[0097] In this embodiment, the number of movable-side built-in rotating arms 3 is set to be the same as the number of injection molding stations. During injection molding, the movable-side built-in rotating arms 3 correspond one-to-one with the injection molding stations. A plurality of movable-side built-in rotating arms 3 are radially arranged on the driving assembly, and the driving assembly drives the plurality of movable-side built-in rotating arms 3 to rotate simultaneously. In this embodiment, the number of movable-side built-in rotating arms 3 is six.

[0098] During injection molding, a plurality of thick-walled plastic parts are injection molded simultaneously:

[0099] After the first movable-side built-in rotating arm 3 completes the injection molding of the first-layer structure at the first injection molding station, it drives the first-layer structure to move to the second injection molding station. At the same time, the second movable-side built-in rotating arm 3 moves to the first injection molding station to perform the injection molding of the first-layer structure;

[0100] After the first movable-side built-in rotating arm 3 completes the injection molding of the second-layer structure at the second injection molding station, it drives the combination of the first-layer structure and the second-layer structure to move to the third injection molding station to perform the injection molding of the third-layer structure. At the same time, the second movable-side built-in rotating arm 3 drives the first-layer structure to move to the second injection molding station to perform the injection molding of the second-layer structure, and the third movable-side built-in rotating arm 3 moves to the first injection molding station to perform the injection molding of the first-layer structure;

[0101] After the first movable-side built-in rotating arm 3 completes the injection molding of the third-layer structure at the third injection molding station, it drives the combination of the first-layer structure, the second-layer structure, and the third-layer structure to move to the fourth injection molding station to perform the injection molding of the fourth-layer structure. At the same time, the second movable-side built-in rotating arm 3 drives the combination of the first-layer structure and the second-layer structure to move to the third injection molding station to perform the injection molding of the third-layer structure, the third movable-side built-in rotating arm 3 drives the first-layer structure to move to the second injection molding station to perform the injection molding of the second-layer structure, and the fourth movable-side built-in rotating arm 3 moves to the first injection molding station to perform the injection molding of the first-layer structure;

[0102] And so on.

[0103] In this embodiment, a plastic injection is performed on the mold clamping of the fixed station and the movable station through an injection structure, and a runner for injecting plastic is provided inside the injection structure.

[0104] The injection runner for injection molding the first-layer structure is the first runner. The first runner is located in the middle area of the connecting body structure in the thickness direction. The width direction and the length direction of the first runner are the same as the length direction of the connecting body structure, and the width of the first runner is the same as the width of the connecting body structure.

[0105] In this embodiment, j is an odd number greater than or equal to 1 and less than 2n + 1. When n is 3, there are 7 layers of structures. Therefore, j is 1, 3, and 5 in sequence.

[0106] When j is 1, the injection runner for injection molding the second-layer structure is the second runner, and the injection runner for injection molding the third-layer structure is the third runner. The third runner and the second runner are respectively arranged on both sides of the first runner. The second runner is located on the movable side, and the third runner is located on the fixed side.

[0107] When j = 3, the injection runner for injection molding the fourth-layer structure is the 4th runner, and the injection runner for injection molding the fifth-layer structure is the 5th runner. The 5th runner and the 4th runner are respectively arranged on both sides of the first runner. The 4th runner is located on the movable side, and the 5th runner is located on the fixed side.

[0108] When j = 5, the injection runner for injection molding the sixth-layer structure is the 6th runner, and the injection runner for injection molding the seventh-layer structure is the 7th runner. The 7th runner and the 6th runner are respectively arranged on both sides of the first runner. The 6th runner is located on the movable side, and the 7th runner is located on the fixed side.

[0109] The injection structure is formed by the combination of the movable injection structure and the fixed injection structure. The movable injection structure is connected to the movable working position, and the fixed injection structure is connected to the fixed working position. The even-numbered runners are all arranged on the movable injection structure, and the odd-numbered runners are all arranged on the fixed injection structure.

[0110] All the even-numbered runners are arranged in one layer or multiple layers. For multiple runners in a single layer, they are distributed from both sides to the middle in the width direction in sequence. For multiple layers, they are distributed from the middle to one side in the thickness direction in sequence.

[0111] All the odd-numbered runners are arranged in one layer or multiple layers. For multiple runners in a single layer, they are distributed from both sides to the middle in the width direction in sequence. For multiple layers, they are distributed from the middle to one side in the thickness direction in sequence.

[0112] In this embodiment, the 2nd runner, the 4th runner, and the 6th runner are arranged in one layer, and the 3rd runner, the 5th runner, and the 7th runner are arranged in one layer.

[0113] As Figure 20 shown, the 2nd runner is arranged at the leftmost side of the area on one side of the first runner, the 3rd runner is correspondingly arranged at the leftmost side of the area on the other side of the first runner, the 4th runner is arranged at the rightmost side of the area on one side of the first runner, the 5th runner is correspondingly arranged at the rightmost side of the area on the other side of the first runner, the 6th runner is arranged between the 2nd runner and the 4th runner, and the 7th runner is correspondingly arranged between the 3rd runner and the 5th runner.

[0114] The relationship between the number of layers of the thick-walled plastic part and n is that the number of layers is 2n + 1, and the number of runners is the same as the number of layers.

[0115] When n is odd, the number of runners arranged in a single layer on one side of the first runner is odd. For example, when n = 3, there are 3 runners arranged in a single layer; when n = 5, there are 5 runners arranged in a single layer; when n = 7, there are 7 runners arranged in a single layer, and so on.

[0116] When n is an even number and its factors do not include odd numbers greater than 1, the number of flow channels set in each layer is an even number. For example, when n is 2, 2 flow channels are set in a single layer; when n is 4, 2 or 4 flow channels are set in a single layer; when n is 8, 2, 4, or 8 flow channels are set in a single layer, and so on.

[0117] When n is an even number and its factors include odd numbers greater than 1, the number of flow channels set in each layer is an even number or an odd number. For example, when n is 6, 2 or 3 flow channels are set in a single layer; when n is 10, 2 or 5 flow channels are set in a single layer, and so on.

[0118] Example 2:

[0119] Those skilled in the art can understand this embodiment as a more specific description of Embodiment 1.

[0120] This embodiment provides a high-efficiency and high-quality injection molding device and method for a thick-walled lens with 2n + 1 (odd) layers.

[0121] In this embodiment, the thick-walled plastic part is divided into a 7-layer structure, and 6 injection molding stations are set. In other embodiments, it is not limited to a 7-layer structure and 6 injection molding stations.

[0122] Figure 1 It is a fixed-side view, which is a fixed-side parting surface view of a monochromatic six-station injection molding die. The figure shows the outer shape of the fixed side of the die, and the positions of the gate of the first-layer injection point 5, the gate of the second-layer injection point 7, the gate of the third-layer injection point 9, the gate of the fourth-layer injection point 11, the gate of the fifth-layer injection point 13, and the gate of the seventh-layer injection point 17 are marked in the figure.

[0123] Among them, the gate of the first-layer injection point 5, the gate of the second-layer injection point 7, the gate of the third-layer injection point 9, the gate of the fourth-layer injection point 11, the gate of the fifth-layer injection point 13, and the gate of the seventh-layer injection point 17 all inject the plastic required for forming by the screw on the fixed side.

[0124] Figure 2 It is a movable-side view, which shows the movable-side parting surface view of the die. It is the movable side of the injection molding die, which is the outer shape of the movable side of the die. The position of the gate of the sixth-layer injection point 15 is marked in the figure.

[0125] In this embodiment, the plastic required for forming is injected by the screw located on the movable side of the molding machine. However, it is also possible to inject the plastic required for the sixth injection by the screw on the fixed side through appropriate runner design. To ensure the pressure balance of the sixth station, the sixth injection and the seventh injection should be made simultaneously. This can prevent the parts formed at the first to fifth stations from deforming under a single force pressure.

[0126] Figure 3 It is a movable-side view showing the rotating arm.Figure 4 A movable side view showing the moving direction of the rotating arm.

[0127] As Figures 5 to 10 shown, the product parts and shapes corresponding to the forming at each station are described.

[0128] Figure 6 A movable side view showing Product Layer 2. Figure 7 A movable side view showing Product Layer 3. Figure 8 A movable side view showing Product Layer 4. Figure 9 A movable side view showing Product Layer 5. Figure 10 A movable side view showing Product Layer 6. Figure 11 A movable side view showing Product Layer 7.

[0129] As Figure 5 shown, it is a movable side view showing Product Layer 1, showing the position of the injection point gate 5 of the first layer. The first layer structure 4 in the figure is the shape formed at the first station. Both sides of the product are in contact with the steel. The SEC A-A view in the upper left corner of the figure is a schematic cross-sectional view of the right structure along the A-A line.

[0130] As Figure 6 shown, it is a movable side view showing Product Layer 2, showing the position of the injection point gate 7 of the second layer. The second layer structure 6 in the figure is the shape formed at the second station, and the cavity is located on the movable side. The SEC B-B view in the lower left corner of the figure is a schematic cross-sectional view of the right structure along the B-B line.

[0131] As Figure 7 shown, it is a movable side view showing Product Layer 3, showing the position of the injection point gate 9 of the third layer. The third layer structure 8 in the figure is the shape formed at the third station, and the cavity is located on the fixed side. The SEC C-C view below the figure is a schematic cross-sectional view of the upper structure along the C-C line.

[0132] As Figure 8 shown, it is a movable side view showing Product Layer 4, showing the position of the injection point gate 11 of the fourth layer. The fourth layer structure 10 in the figure is the shape formed at the fourth station, and the cavity is located on the movable side. The SEC D-D view in the lower right corner of the figure is a schematic cross-sectional view of the left structure along the D-D line.

[0133] As Figure 9 shown, it is a movable side view showing Product Layer 5, showing the position of the injection point gate 13 of the fifth layer. The fifth layer structure 12 in the figure is the shape formed at the fifth station, and the cavity is located on the fixed side. The SEC E-E view in the upper right corner of the figure is a schematic cross-sectional view of the left structure along the E-E line.

[0134] As Figure 10As shown, it is a movable side view showing Product Layer Six and Product Layer Seven, displaying the positions of the injection gates 15 of the sixth layer and the injection gates 17 of the seventh layer. The structures 14 of the sixth layer and 16 of the seventh layer in the figure correspond to the shapes formed at the sixth station. Among them, the cavity of the sixth layer structure 14 is on the movable side, and the cavity of the seventh layer structure 16 is on the fixed side. The SEC F-F diagram in the upper right corner of the figure is a schematic cross-sectional view of the lower structure along the E-E line.

[0135] Figure 11 It is a movable side view showing the schematic of product removal. Figure 12 It is a three-dimensional structure schematic diagram of the thick-walled plastic part 25. Figure 13 It is a planar structure schematic diagram of the thick-walled plastic part 25.

[0136] Figure 14 The SEC B-B diagram on the left in the figure is Figure 13 a schematic cross-sectional view along the B-B line. Figure 14 The SEC A-A diagram on the right in the figure is Figure 13 a schematic cross-sectional view along the A-A line.

[0137] Figure 15 It is a three-dimensional structure schematic diagram of the thick-walled plastic part 25 with a runner injection structure 26 formed by the runner in the injection structure. Figure 16 It is a planar structure schematic diagram of the thick-walled plastic part 25 with a runner injection structure 26 formed by the runner in the injection structure.

[0138] Figure 17 The SEC C-C diagram in the figure is Figure 16 a schematic cross-sectional view along the C-C line. The figure shows the first injection-formed runner 24, the sixth injection-formed runner 22, and the seventh injection-formed runner 23.

[0139] Figure 18 The SEC D-D diagram in the figure is Figure 16 a schematic cross-sectional view along the D-D line. The figure shows the second injection-formed runner 18 and the third injection-formed runner 19.

[0140] Figure 19 The SEC E-E diagram in the figure is Figure 16 a schematic cross-sectional view along the E-E line. The figure shows the fourth injection-formed runner 20 and the fifth injection-formed runner 21.

[0141] As Figure 20 shown, it demonstrates the ingeniously designed gate / runner stacking method to achieve the above forming sequence. The first injection-formed runner 24 in the figure is the cross-section of the runner formed at the first station. Its thickness is about 3 - 6 mm, and its width is 8 - 15 mm. The second injection-formed runner 18 in the figure is the cross-section of the runner formed at the second station. The main part of the cold runner has a thickness of about 2 - 5 mm and a width of about 3 - 5 mm.

[0142] Since the second injection cavity is located on the movable side, the main part of the cold runner is also located on the movable side. To enable injection from the fixed side, a cold runner located on the fixed side is designed beside the first injection runner, and a part of the second injection runner located on the movable side is extended so that the two partially overlap, realizing the connection between the hot gate on the fixed side and the cold runner on the movable side.

[0143] A new side runner structure is added to one side of the structure for forming the runner. By forming a side runner in the side runner structure, the runner on the movable side is connected, and the gate is led to the fixed side.

[0144] The third injection molding runner 19 in the figure is the cross-section of the runner formed in the third station. The thickness is about 2 - 5 mm, and the width is about 3 - 5 mm. The fourth injection molding runner 20 in the figure is the cross-section of the runner formed in the fourth station. The main part of the cold runner has a thickness of about 2 - 5 mm and a width of about 3 - 5 mm.

[0145] Since the fourth injection cavity is located on the movable side, the main part of the cold runner is also located on the movable side. To enable injection from the fixed side, a cold runner located on the fixed side is designed beside the first injection runner, and a part of the fourth injection runner located on the movable side is extended so that the two partially overlap, realizing the connection between the hot gate on the fixed side and the cold runner on the movable side.

[0146] A new side runner structure is added to one side of the structure for forming the runner. By forming a side runner in the side runner structure, the runner on the movable side is connected, and the gate is led to the fixed side.

[0147] The fifth injection molding runner 21 in the figure is the cross-section of the runner formed in the fifth station. The thickness is about 2 - 5 mm, and the width is about 3 - 5 mm. The sixth injection molding runner 22 and the seventh injection molding runner 23 in the figure are the cross-sections of the runners formed in the sixth station. The main body part has a thickness of about 2 - 5 mm and a width of about 3 - 5 mm.

[0148] Among them, the sixth injection molding runner 22 is formed by injection from the screw on the movable side, and the hot gate is directly set in the middle of the runner. The seventh injection molding runner 23 is formed by injection from the screw on the fixed side, and the hot gate is directly set in the middle of the runner.

[0149] Figure 20It is the cross-sectional shape of the main part of the cold runner. The first injection molding runner 24 is the runner corresponding to the first-layer structure 4. The second injection molding runner 18 is the runner corresponding to the second-layer structure 6. The third injection molding runner 19 is the runner corresponding to the third-layer structure 8. The fourth injection molding runner 20 is the runner corresponding to the fourth-layer structure 10. The fifth injection molding runner 21 is the runner corresponding to the fifth-layer structure 12. The sixth injection molding runner 22 is the runner corresponding to the sixth-layer structure 14. The seventh injection molding runner 23 is the runner corresponding to the seventh-layer structure 16.

[0150] Figure 3 and Figure 4 It shows a swivel arm fork design for ejecting the product formed at the first station and bringing it to the next station. The rotational power is driven by a motor installed on the movable side of the mold. The ejection power is provided by the ejector rod of the molding machine. At one end of the rotating arm 3 built into the movable side close to the product, two or more pins are provided and extend into the cavity beside the runner body of the first-shot molding. The plastic injected at the first station will wrap around the pins. Under the action of the resin shrinkage force, the formed product will tightly hold the swivel arm. So that the product is firmly fixed on the swivel arm without loosening during the process from the first station to the sixth station. After the injection is completed at the sixth station and the product is ejected, the complete product is taken out from the swivel arm by a manipulator or manually.

[0151] In this embodiment, through multi-layer injection molding, first injecting the core part of the product and then injecting the two sides of the product in multiple layers and in a layered manner, so that the resin of each layer is cooled most sufficiently. Solve the problem of long molding cycle.

[0152] In this embodiment, through multi-layer injection molding, injecting the next layer on the basis of the part of the product that has been sufficiently cooled before, so that the shrinkage generated by the previous layer of the product is compensated during the injection of the next layer. Through the injection compensation of multiple stations, the lens shape deviation caused by the natural shrinkage of the resin can be minimized.

[0153] In this embodiment, the light-emitting surface of the lens usually needs to be processed with complex and expensive micro-structured patterns. This design only forms the last layer on the front and back of the product at the last station. So only an optical micro-structured insert needs to be set at the last station.

[0154] In this embodiment, both PC and PMMA are poor conductors of heat. The thermal conductivity of typical die steel is approximately 29 W / m²°C. Generally speaking, the thermal conductivity of plastic PMMA and PC is no higher than 0.29 W / m²°C, which is more than 100 times that of the latter. To enable the heat of the plastic to be dissipated faster, more of the injected resin needs to be in contact with the steel. This design first injects the core part of the product, allowing the core part of the product to cool sufficiently first, and then sequentially stacks high-temperature resin on the formed part on the front or back of the already formed part. In this way, one side of the product formed in the previous injection can still remain in contact with the steel in the 2nd to 5th stations, continuously removing the heat of the product. One side of the newly injection-molded part will continuously contact the die steel in the next station, continuously removing the heat of the product.

[0155] In this embodiment, due to the optical requirements of the lens, extremely high requirements are placed on the shape accuracy of the light-incident surface and the light-emitting surface. Through a clever design, this design places the two surfaces with the highest requirements in the last station for forming. At this time, most of the core material of the lens has been sufficiently cooled, and the resin shrinkage has also been fully compensated during the forming of the first layer. On this basis, the light-incident surface and the light-emitting surface of the product are formed simultaneously, converting thick-wall injection molding into general thin-wall injection molding, greatly improving the shape accuracy of the optical lens. Even if it is necessary to adjust the cavity shape of the light-incident surface and the light-emitting surface for some reason, only the corresponding inserts in the last station need to be adjusted.

[0156] The forming challenge of thick-wall injection molded parts lies in the extremely long forming cycle and the shrinkage that is difficult to be compensated. In this embodiment, by cleverly dividing the injection molding layers of the thick-wall parts, an injection molding sequence that best conforms to the heat transfer law is designed, combined with the multi-layer injection molding method, to achieve the goal of efficiently producing thick-wall injection molded parts with low shrinkage and high precision.

[0157] To address the problems encountered by thick-wall plastic parts in injection molding mentioned in the prior art, in this embodiment, the entire product is divided into an odd number of layers. Figure 14 Shows the cross-sections of the product in two perpendicular directions when divided into 7 layers. Figure 23 The process shows the possible injection molding sequence of this layered design. The first structure 4 to be injection molded, and the second structure 6 and the third structure 8 can be injection molded simultaneously or sequentially. The fourth structure 10 and the fifth structure 12 can also be injection molded simultaneously or sequentially. The sixth structure 14 and the seventh structure 16 can also be injection molded simultaneously or sequentially. Specifically, the most suitable method can be selected according to the conditions of the equipment.

[0158] The second - layer structure 6 and the third - layer structure 8 cover the first - layer structure. When choosing whether to inject - mold the second - layer structure 6 or the third - layer structure 8 first, this is free, as long as the corresponding runners and gates are provided. When the corresponding runners and gates are opened, it is possible to inject - mold the second - layer structure 6 and the third - layer structure 8 simultaneously. As Figure 26 shown, when the molding machine has injection barrels on both the fixed side and the movable side, two hot runners can be used to inject simultaneously from A and B. When the molding machine only has an injection barrel on the fixed side, a runner cavity C can be opened to connect the injection channels of the second - layer structure 6 and the third - layer structure 8, so that only by injecting from A can the purpose of simultaneously injecting the second - layer structure 6 and the third - layer structure 8 be achieved.

[0159] As Figure 25 shown, the dimension h refers to the maximum wall thickness of a single - layer structure. The thickness of an optical lens used in a typical headlight can reach 20 - 35 mm. h1 is the thickness of the first layer, h2 is the thickness of the second layer, h3 is the thickness of the third layer, h4 is the thickness of the fourth layer, h5 is the thickness of the fifth layer, h6 is the thickness of the sixth layer, and h7 is the thickness of the seventh layer.

[0160] Among them, the wall thickness of the first - layer structure 4 needs to be larger than that of other layers to achieve higher injection - molding efficiency. In a preferred embodiment, the wall - thickness ratio is such that the maximum wall thickness of the first - layer structure 4 is twice the maximum wall thickness of the second - layer structure 6. For the intermediate layers of the second - layer structure 6, the third - layer structure 8, the fourth - layer structure 10, and the fifth - layer structure 12, their maximum wall thicknesses are kept equal or at least close. This can make the intermediate injection - molded layers have almost the same or similar cooling curves. For the sixth - layer structure 14 and the seventh - layer structure 16, which are the surface layers of the product, the wall thickness is kept uniform and less than that of the intermediate layers. The typical range of the sixth - layer structure 14 and the seventh - layer structure 16 is 1.5 - 5 mm.

[0161] Taking a product with a wall thickness of 25 mm made of PMMA material as an example, by using the above seven - layer injection - molding method, the molding cycle can be shortened to 100 - 150 seconds.

[0162] In this embodiment, through the odd - layer hierarchical injection - molding method, the molding cycle can be greatly reduced, the surface quality of the plastic part can be improved, and strict optical requirements can be met.

[0163] In this embodiment, the thick-walled injection molded part is innovatively divided into an odd number of layers, and an appropriate gate design is required. A clever gate design can maximize the advantages of short multi-layer injection molding cycle and full compensation for plastic part shrinkage. In this embodiment, through a clever stacked runner design, the injection molding of plastic parts divided into an odd number of layers becomes possible. At the same time, the compactness of the gate is taken into account, and the gates are maximally concentrated in one place. The subsequent laser cutting of the gates is very convenient, minimizing the residual marks of the gates after cutting.

[0164] Figure 12 There is a thick-walled plastic part of the product. Taking the lens of an automotive headlight mold as an example, the thickness is often 25 - 35 mm. If a single-layer forming method is used for injecting plastic parts of this thickness, the forming cycle can be as long as 20 - 30 minutes or even longer. As an alternative to single-layer injection molding, multi-layer injection molding can greatly reduce the forming cycle.

[0165] Taking seven-layer injection molding as an example, the forming cycle can be reduced by about 90%, and the product quality is higher and the optical performance is more excellent. For the 2n + 1 (odd number) layering scenario developed for multi-layer injection molding, this embodiment cleverly designs the gates and runners that can adapt to thick-walled plastic parts injected layer by layer from the inside out. By using the thickest first injection molding runner 24 as the basis of the stack, the corresponding gates and runners of the subsequent forming layers are superimposed on the front and back of the first injection molding runner, corresponding to the second injection molding runner 18, the third injection molding runner 19, the fourth injection molding runner 20, the fifth injection molding runner 21, the sixth injection molding runner 22, and the seventh injection molding runner 23 in turn.

[0166] By setting the first injection molding runner 24 to be the widest and thickest, taking seven-layer injection molding with a maximum thickness of 25 mm as an example, the thickness of the gate of the first layer is 3 - 6 mm, and the width of the runner has a relatively large selection range depending on the product size. The goal is to ensure that the products of the first layer are fully pressure-maintained and compensated for shrinkage. By setting the second injection molding runner 18, the third injection molding runner 19, the fourth injection molding runner 20, and the fifth injection molding runner 21 in the middle layer to be of similar sizes, the middle layer, which already has a similar thickness, can also obtain almost the same pressure-maintaining and shrinkage compensation windows. In the case of seven-layer injection molding, by setting the sixth injection molding runner 22 and the seventh injection molding runner 23 in the center of the already formed gate runner, since the three sides of the runner are all plastic at this time, the heat dissipation speed is much slower than that of direct contact with steel, which delays the thermal cutting time of the runner as much as possible. Taking the scenario of seven-layer injection molding with a thickness of 25 mm as an example, placing the sixth injection molding runner 22 and the seventh injection molding runner 23 in the middle can extend the available pressure-maintaining window by more than twice. A longer pressure-maintaining and feeding time window makes the entire injection molding of the plastic part in a wider forming window, making the injection molding process stronger and more robust. While the quality of the plastic part is more excellent, it also makes industrial production more stable.

[0167] Figure 21 and Figure 22 shows an extended case of the gate runner stack design. Figure 21 Shows adaptation to multi-layer injection molding scenarios such as 7 layers, 13 layers, 19 layers, etc. Figure 11 Shows adaptation to injection molding scenarios where the plastic part is divided into 5 layers, 9 layers, 13 layers, and so on.

[0168] In this embodiment, by cleverly adopting the structure of the gate runner stack design, the problem of sufficient filling balance and pressure holding for each layer of the odd-layer plastic part is solved, minimizing the shrinkage of the final product.

[0169] In this embodiment, by integrating the gates of multi-layer injection molding in one place, the subsequent gate removal process is simple, minimizing the gate residual marks and the impact on the appearance.

[0170] In this embodiment, by setting the gates and runners of the last two formed layers in the middle of the existing runner, the formed pressure holding window is widened as much as possible, achieving stable and strong injection molding process, and higher and more stable product quality.

[0171] Example 3:

[0172] Those skilled in the art can understand this embodiment as a more specific description of Embodiment 1.

[0173] In this embodiment, by cleverly dividing the injection molding levels of the thick-walled lens and selecting the injection molding sequence that most conforms to the heat transfer law, the goal of low equipment investment and efficient production of high-quality lenses is achieved. This embodiment injects and forms a thick-walled plastic part divided into 2n + 1 layers with 2n stations, greatly improving the forming efficiency of the thick-walled plastic part. In the last station, the outermost layer is injected simultaneously on both sides to achieve the purpose of accurately controlling the important surface dimensions, especially suitable for the shape control of the light incident surface and the light exit surface of the thick-walled lens.

[0174] Taking the mold for injecting and forming a thick-walled plastic part divided into 7 layers with 6 stations as an example in this embodiment, 7 layers and 6 stations are only an example of the preferred scheme and are not limited to 7 layers.

[0175] The fixed mold 1 is the fixed side of the mold for injection molding.

[0176] The movable mold 2 is the movable side of the mold for injection molding. The built-in rotating arm 3 on the movable side is an electric rotating arm built into the movable mold 2. As Figure 4 shown, the arrow indicates the schematic rotation direction of the rotating arm.

[0177] The first layer structure 4 is the product and runner formed by injection molding at the first station, and the first layer injection point gate 5 is the point gate of the first layer structure 4.

[0178] Due to the ingenious insertion of the fork needle of the rotatable arm 3 built into the movable side into the flow channel cavity of the first-layer structure 4, after the first-layer structure 4 is injection-molded and cooled, the first-layer structure 4 will be tightly clamped on the fork needle of the rotatable arm 3 built into the movable side. When the molding machine opens the mold, the rotatable arm 3 built into the movable side will be ejected from the movable mold and rotated by 60 degrees, bringing the first-layer structure 4 above the second station. Then, the ejected rotatable arm 3 built into the movable side retracts back into the movable mold 2, and at the same time, the first-layer structure 4 is brought into the cavity of the second station. At the second station, after the mold is closed, the first-layer structure 4 will remain in contact with the steel of the fixed mold 1, which can allow the plastic part to dissipate heat continuously and efficiently. The cavity of the second layer is mainly on the movable side of the mold. The second-layer structure 6 is stacked on the first-layer structure 4 by injection molding. The second-layer injection point gate 7 is where the gate of the second-layer structure 6 is located. In this example, the second-layer injection point gate 7 is on the fixed side, but if the injection molding machine supports it, the second-layer injection point gate 7 may also be set on the movable side.

[0179] After the second-layer structure 6 is injection-molded and cooled, the molding machine opens the mold. The rotatable arm 3 built into the movable side is ejected again and rotated by 60 degrees and then retracts back into the movable mold 2, and at the same time, the second-layer structure 6 is brought into the third station. At the third station, after the mold is closed, the second-layer structure 6 will remain in contact with the steel of the movable mold 2, which can allow the second-layer structure 6 to dissipate heat continuously and efficiently. The cavity of the third layer is mainly on the fixed side of the mold. The third-layer structure 8 is stacked on the combined body of the first-layer structure 4 and the second-layer structure 6 by injection molding. The third-layer injection point gate 9 is where the gate of the third-layer structure 8 is located. In this example, the third-layer injection point gate 9 is on the fixed side, but if the injection molding machine supports it, the third-layer injection point gate 9 may also be set on the movable side.

[0180] After the third-layer structure 8 is injection-molded and cooled, the molding machine opens the mold. The rotatable arm 3 built into the movable side is ejected again and rotated by 60 degrees and then retracts back into the movable mold 2, and at the same time, the third-layer structure 8 is brought into the fourth station. At the fourth station, after the mold is closed, the third-layer structure 8 will remain in contact with the steel of 1, which can allow the third-layer structure 8 to dissipate heat continuously and efficiently. The cavity of the fourth layer is mainly on the movable side of the mold. The fourth-layer structure 10 is stacked on the combined body of the first-layer structure 4, the second-layer structure 6, and the third-layer structure 8 by injection molding. The fourth-layer injection point gate 11 is where the gate of the fourth-layer structure 10 is located. In this example, the fourth-layer injection point gate 11 is on the fixed side, but if the injection molding machine supports it, the fourth-layer injection point gate 11 may also be set on the movable side.

[0181] After the fourth layer structure 10 is injected and cooled, the molding machine opens the mold, and the built-in rotating arm 3 on the movable side is ejected again and rotated 60 degrees before returning to the movable mold 2, and the fourth layer structure 10 is brought into the fifth station. At the fifth station, the fourth layer structure 10 will keep in contact with the steel of the movable mold 2 after the mold is closed, so that the fourth layer structure 10 can continue to dissipate heat efficiently. The cavity of the fifth layer is mainly on the fixed side of the mold. The fifth layer structure 12 is superimposed on the combination of the first layer structure 4, the second layer structure 6, the third layer structure 8 and the fourth layer structure 10 by injection molding. The fifth layer injection point gate 13 is where the gate of the fifth layer structure 12 is located. In this example, the fifth layer injection point gate 13 is on the fixed side, but if the injection molding machine supports it, the fifth layer injection point gate 13 may also be set on the movable side.

[0182] After the fifth layer structure 12 is injected and cooled, the molding machine opens the mold, and the built-in rotating arm 3 on the movable side is ejected again and rotated 60 degrees before returning to the movable mold 2, and the fifth layer structure 12 is brought into the sixth station. At the sixth station, the fifth layer structure 12 will remain suspended after the mold is closed, because at this station, the front and back sides of the outermost layer of the product need to be injection molded at the same time. The cavity of the sixth layer is mainly on the fixed side of the mold, and the cavity of the seventh layer is mainly on the fixed side of the mold. In order to prevent the suspended plastic parts from deviating to one side under the pressure of the fluid, the sixth layer structure 14 and the seventh layer structure 16 should be superimposed on the combination of the first layer structure 4, the second layer structure 6, the third layer structure 8, the fourth layer structure 10 and the fifth layer structure 12 by simultaneous injection molding. The sixth layer injection point gate 15 is where the gate of the sixth layer structure 14 is located. The seventh layer injection point gate 17 is where the gate of the seventh layer structure 16 is located. In this example, the sixth injection point gate 15 is located on the movable side, and the seventh injection point gate 17 is on the fixed side. Such a runner is the simplest and shortest, which has obvious benefits for improving the pressure holding quality of plastic parts. However, if the position of the injection molding machine barrel does not support it, the sixth injection point gate 15 and the seventh injection point gate 17 may also be set on the movable side of the molding machine.

[0183] After the sixth layer structure 14 and the seventh layer structure 16 are injected and cooled, the molding machine opens the mold, and the movable side built-in rotating arm 3 is ejected again. The finished product is taken out from 3 by the robot, and the runner is removed in the next process to obtain the product. The rotating arm continues to rotate and enters the next molding cycle.

[0184] The above-mentioned forming steps can be extended to the case of forming a thick-walled plastic part with 2n (even) layers at 2n (even) workstations. In this embodiment, a thick-walled plastic part divided into 2n + 1 (odd) layers is injection-molded at 2n (even) workstations, greatly improving the forming efficiency of the thick-walled plastic part. At the last workstation, the outermost layer is injection-molded simultaneously on the front and back sides to achieve the purpose of accurately controlling the important surface dimensions, which is particularly suitable for the shape control of the light incident surface and the light exit surface of a thick-walled lens.

[0185] In this embodiment, through a clever mold design, it is possible to set the outer shell that has the greatest impact on the product surface at the last workstation, and it becomes possible for two different screws to control the injection molding parameters of the front and back sides of the product (in the case of a lens, respectively control the forming parameters of the light incident surface layer and the light exit surface layer). The goal of producing thick-walled parts with low shrinkage and high precision is achieved.

[0186] In this embodiment, by first injection-molding the center of the product and then layer-by-layer injection-molding on the front and back sides, the problems of difficult heat dissipation in the core of a single-color injection-molded product, long cooling time, and large product shrinkage are solved. The benefit of more efficiently using the mold steel to cool the plastic part is achieved, greatly reducing the forming cycle of the plastic part, and the benefit of large-scale mass production is very obvious.

[0187] In this embodiment, by setting the outer shell that has the greatest impact on the product surface at the last workstation, the processing accuracy requirements for the product cavity in the previous workstations are also greatly alleviated. If there are scratches or roughness on the cavity of the previous workstations, they can be fully melted by the high-temperature resin formed by the next layer of superposition. The pressure of mold maintenance is greatly reduced.

[0188] In this embodiment, by setting the outer shell that has the greatest impact on the product surface at the last workstation, only the cavity of the last workstation needs to be processed with high precision, greatly reducing the processing cost of the mold and the possible subsequent design change costs.

[0189] In this embodiment, by first injection-molding the center of the product and then layer-by-layer injection-molding on the front and back sides, the problems of short holding pressure window time and large product shrinkage in single-color injection-molded products are solved. The condition is created where the plastic part can be fully held under pressure at each layer, and the shrinkage of the plastic part in the previous workstation can be compensated by the next workstation, resulting in a low shrinkage of the final product, which is suitable for the large-scale mass production of plastic parts with strict precision requirements (such as optical lenses).

[0190] Example 4:

[0191] Those skilled in the art can understand this embodiment as a more specific illustration of Embodiment 1.

[0192] Such as Figures 1 to 26As shown in the figure, this embodiment provides a multi-layer injection molding method for thick-walled plastic parts, including the following steps:

[0193] Layer structure division step: Divide the thick-walled plastic part into 2n + 1 layer structures, namely the first layer structure to the (2n + 1)-th layer structure. The first layer structure is located in the central area of the thick-walled plastic part, and the second layer structure to the (2n + 1)-th layer structure are evenly distributed on both sides of the first layer structure; n is a natural number;

[0194] Multi-layer injection molding step: Set 2n injection molding stations, and sequentially inject through the 2n injection molding stations to form the first layer structure to the (2n + 1)-th layer structure of the thick-walled plastic part; Inject through the first injection molding station to form the first layer structure;

[0195] When n is equal to 1, inject through the second injection molding station to form the second layer structure and the third layer structure respectively located on both sides of the first layer structure;

[0196] When n is greater than 1, when injecting through the second injection molding station to the (2n - 1)-th injection molding station, sequentially and alternately form the second layer structure to the (2n - 1)-th layer structure on both sides of the first layer structure; The previous injection molding station injects to form a layer structure on one side of the first layer structure, and the next injection molding station injects to form another layer structure at the relative position on the other side of the first layer structure; Inject through the 2n-th injection molding station to form the 2n-th layer structure and the (2n + 1)-th layer structure, and the 2n-th layer structure and the (2n + 1)-th layer structure form the surface layer structure of the thick-walled plastic part.

[0197] For the second layer structure to the (2n + 1)-th layer structure, the even layer structures and the odd layer structures are sequentially and alternately formed on both sides of the first layer structure; The next even layer structure covers the previous even layer structure, and the next odd layer structure covers the previous odd layer structure. For the second layer structure to the (2n + 1)-th layer structure, the even layer structures are formed on the movable side of the injection molding station, and the odd layer structures are formed on the fixed side of the injection molding station.

[0198] The multi-layer injection molding step specifically includes the following steps:

[0199] Step S1: Set a moving component and 2n injection molding stations, arrange the 2n injection molding stations so that the moving component can sequentially reach the first injection molding station to the 2n-th injection molding station;

[0200] Step S2: Make the moving component reach the first injection molding station, close the fixed station and the movable station of the first injection molding station, and inject to form the first layer structure;

[0201] Among them, a connection structure on the moving component can be located in the cavity of the first injection molding station. The first layer structure can be fixed on the connection structure, and the moving component can drive the first layer structure to move;

[0202] In step S2, when injecting the first layer structure, the cavity for injecting the first layer structure is partially located on the fixed station and partially located on the workable station. Both sides of the first layer structure can be in contact with the fixed station and the workable station respectively for heat conduction;

[0203] Step S3: Open the mold of the fixed station and the workable station of the first injection molding station. Push out the first layer structure from the workable station of the first injection molding station through the moving component, and then move the first layer structure to the workable station of the second injection molding station through the moving component;

[0204] Step S4: Close the mold of the fixed station and the workable station of the second injection molding station. Inject and form a second layer structure connected to the first layer structure on one side of the first layer structure;

[0205] In step S4, when injecting the second layer structure, the cavity for injecting the second layer structure is located on the workable station, and the other side of the first layer structure can be in contact with the fixed station for heat conduction;

[0206] Step S5: Open the mold of the fixed station and the workable station of the second injection molding station. Push out the combination of the first layer structure and the second layer structure from the workable station of the second injection molding station through the moving component, and then move the combination of the first layer structure and the second layer structure to the workable station of the third injection molding station through the moving component;

[0207] Step S6: Close the mold of the fixed station and the workable station of the third injection molding station. Inject and form a third layer structure connected to the first layer structure on the other side of the first layer structure;

[0208] In step S6, when injecting the third layer structure, the cavity for injecting the third layer structure is located on the fixed station, and the second layer structure can be in contact with the workable station for heat conduction;

[0209] Step S7: Open the mold of the fixed station and the workable station of the third injection molding station. Push out the combination of the first layer structure, the second layer structure, and the third layer structure from the workable station of the third injection molding station through the moving component, and then move the combination of the first layer structure, the second layer structure, and the third layer structure to the workable station of the fourth injection molding station through the moving component;

[0210] Among them, if n is greater than 2, then step S8 and step S9 are carried out in sequence. If n is equal to 2, then directly go to step S9;

[0211] Step S8: Close the fixed and movable stations of the a-th injection molding station, and inject on one side of the first-layer structure to form the a-th layer structure connected to the (a - 2)-th layer structure;

[0212] Open the fixed and movable stations of the a-th injection molding station, eject the combined body formed by injection molding at the a-th injection molding station from the movable station of the a-th injection molding station through the moving component, and then move the combined body formed by injection molding at the a-th injection molding station to the movable station of the (a + 1)-th injection molding station through the moving component;

[0213] Close the fixed and movable stations of the (a + 1)-th injection molding station, and inject on the other side of the first-layer structure to form the (a + 1)-th layer structure connected to the (a - 1)-th layer structure;

[0214] Open the fixed and movable stations of the (a + 1)-th injection molding station, eject the combined body formed by injection molding at the (a + 1)-th injection molding station from the movable station of the (a + 1)-th injection molding station through the moving component, and then move the combined body formed by injection molding at the (a + 1)-th injection molding station to the movable station of the (a + 2)-th injection molding station through the moving component;

[0215] a is an even number greater than or equal to 4 and less than 2n, and the fourth-layer structure to the (2n - 1)-th layer structure are sequentially formed through the above steps;

[0216] In step S8, when injecting the a-th layer structure, the cavity for injecting the a-th layer structure is located on the movable station, and the (a - 1)-th layer structure can contact and conduct heat with the fixed station;

[0217] When injecting the (a + 1)-th layer structure, the cavity for injecting the (a + 1)-th layer structure is located on the fixed station, and the a-th layer structure can contact and conduct heat with the movable station;

[0218] Step S9: Close the fixed and movable stations of the 2n-th injection molding station, inject on one side of the first-layer structure to form the 2n-th layer structure connected to the (2n - 2)-th layer structure, and inject on the other side of the first-layer structure to form the (2n + 1)-th layer structure connected to the (2n - 1)-th layer structure;

[0219] In step S9, when injecting the 2n-th layer structure and the (2n + 1)-th layer structure, the cavity for injecting the 2n-th layer structure is located on the movable station, and the cavity for injecting the (2n + 1)-th layer structure is located on the fixed station;

[0220] Step 10: Open the fixed and movable stations of the 2n-th injection molding station, and take out the formed thick-wall plastic part.

[0221] The moving component is connected to the first layer structure through a rotatable arm built into the movable side. The rotatable arm built into the movable side can move the workpiece formed by the previous injection molding station to the next injection molding station; during the entire injection molding process of the thick-walled plastic part, the rotatable arm built into the movable side can always conduct the heat accumulated on the first layer structure.

[0222] In this embodiment, n is 3, and the thick-walled plastic part is divided into 7 layer structures, namely the first layer structure 4, the second layer structure 6, the third layer structure 8, the fourth layer structure 10, the fifth layer structure 12, the sixth layer structure 14, and the seventh layer structure 16. Three layer structures are divided on both sides of the first layer structure. One side is the second layer structure 6, the fourth layer structure 10, and the sixth layer structure 14, and the other side is the third layer structure 8, the fifth layer structure 12, and the seventh layer structure 16;

[0223] In other embodiments, if n is 4, it is divided into 9 layers. There are 4 layer structures on both sides of the first layer structure. One side is the second layer structure, the fourth layer structure, the sixth layer structure, and the tenth layer structure, and the other side is the third layer structure, the fifth layer structure, the seventh layer structure, and the ninth layer structure, and so on;

[0224] In this embodiment, 6 injection molding stations are set. The first layer structure to the seventh layer structure of the thick-walled plastic part are sequentially injection molded through 6 injection molding stations. When injecting at the 2nd to 5th injection molding stations, the second layer structure to the fifth layer structure are alternately formed on both sides of the first layer structure. After the first injection molding station injects and forms the first layer structure, the second injection molding station injects and forms the second layer structure on one side of the first layer structure, the third injection molding station injects and forms the third layer structure at the relative position on the other side of the first layer structure, the fourth injection molding station injects and forms the fourth layer structure connected to the second layer structure on one side of the first layer structure, and the fifth injection molding station injects and forms the fifth layer structure connected to the third layer structure at the relative position on the other side of the first layer structure;

[0225] In this embodiment, the sixth injection molding station injects and forms the sixth layer structure and the seventh layer structure. The sixth layer structure and the seventh layer structure form the surface layer structure of the thick-walled plastic part. The sixth layer structure and the seventh layer structure form the most important structure of the surface layer. In the scenario of a lens, they correspond to the two surfaces with the highest requirements for the shape, namely the incident light surface and the outgoing light surface.

[0226] In this embodiment, the 6 injection molding stations are arranged so that the moving component can sequentially reach the first injection molding station to the sixth injection molding station.

[0227] In this embodiment, n is 3 and a is 4. Then the fixed station and the movable station of the fourth injection molding station are closed for mold clamping, and the fourth layer structure connected to the second layer structure is injection molded on one side of the first layer structure;

[0228] Open the mold for the fixed and movable stations of the fourth injection molding station. Use the moving component to eject the combined body formed by injection molding at the fourth injection molding station from the movable station of the fourth injection molding station, and then use the moving component to move the combined body formed by injection molding at the fourth injection molding station to the movable station of the fifth injection molding station; the combined body is a combination of the first layer structure, the second layer structure, the third layer structure, and the fourth layer structure.

[0229] Close the mold for the fixed and movable stations of the fifth injection molding station, and inject and form the fifth layer structure connected to the third layer structure on the other side of the first layer structure.

[0230] Open the mold for the fixed and movable stations of the fifth injection molding station. Use the moving component to eject the combined body formed by injection molding at the fifth injection molding station from the movable station of the fifth injection molding station, and then use the moving component to move the combined body formed by injection molding at the fifth injection molding station to the movable station of the sixth injection molding station; the combined body is a combination of the first layer structure, the second layer structure, the third layer structure, the fourth layer structure, and the fifth layer structure.

[0231] In other embodiments, if n is 4, then a is 4 and 6 in sequence, and the fourth layer structure to the seventh layer structure are formed in sequence. If n is 5, then a is 4, 6, and 8 in sequence, and the fourth layer structure to the ninth layer structure are formed in sequence, and so on.

[0232] When injecting the fourth layer structure, the cavity for injecting the fourth layer structure is located on the movable station, and the third layer structure can contact and conduct heat with the fixed station; when injecting the fifth layer structure, the cavity for injecting the fifth layer structure is located on the fixed station, and the fourth layer structure can contact and conduct heat with the movable station.

[0233] In this embodiment, close the mold for the fixed and movable stations of the sixth injection molding station, inject and form the sixth layer structure connected to the fourth layer structure on one side of the first layer structure, and inject and form the seventh layer structure connected to the fifth layer structure on the other side of the first layer structure.

[0234] When injecting the sixth layer structure and the seventh layer structure, the cavity for injecting the sixth layer structure is located on the movable station, and the cavity for injecting the seventh layer structure is located on the fixed station.

[0235] Open the mold for the fixed and movable stations of the sixth injection molding station, and take out the formed thick-walled plastic part.

[0236] There are 2n fixed stations arranged circumferentially on the fixed mold; there are 2n movable stations arranged circumferentially on the movable mold; the fixed stations and the movable stations are arranged in one-to-one correspondence, and the 2n fixed stations and the 2n movable stations form 2n injection molding stations; the moving component includes a driving component arranged on the movable mold and a built-in rotating arm on the movable side, and the driving component and the built-in rotating arm on the movable side are located in the annular area formed by the 2n movable stations; the driving component drives the built-in rotating arm on the movable side to rotate, and one end of the built-in rotating arm on the movable side can successively reach the first injection molding station to the 2nth injection molding station; one end of the built-in rotating arm on the movable side forms a connecting structure for fixing the first layer structure and can drive the first layer structure to rotate; the built-in rotating arm on the movable side can move the injection molded part at the previous injection molding station to the next injection molding station through rotation. During the entire injection molding process of the thick-walled plastic part, the built-in rotating arm on the movable side can always export the heat accumulated on the first layer structure. There are pins for fixing the first layer structure arranged on the connecting structure.

[0237] In this embodiment, there are 6 fixed stations arranged circumferentially on the fixed mold; there are 6 movable stations arranged circumferentially on the movable mold; the fixed stations and the movable stations are arranged in one-to-one correspondence, and the 6 fixed stations and the 6 movable stations form 6 injection molding stations.

[0238] The device of the present invention adopts multi-layer injection molding, first injecting the core of the product and then injecting the two sides of the product in multiple layers in a divided manner, so that the resin of each layer can be cooled most sufficiently, and the problem of long molding cycle is solved.

[0239] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0240] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. Without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A multi-layer injection molding device for thick-walled plastic parts, characterized in that, For injection molding to form a thick-walled plastic part divided into 2n + 1 layers, including: a fixed mold (1) and a movable mold (2); There are 2n fixed stations circumferentially distributed on the fixed mold (1), and 2n movable stations circumferentially arranged on the movable mold (2); n is a natural number; The 2n fixed stations and the 2n movable stations form 2n injection molding stations, and a moving component is arranged on the movable mold (2), and the moving component can move the workpiece formed by injection molding at the previous injection molding station to the next injection molding station; The first injection molding station injects and forms the first layer structure in the central area of the thick-walled plastic part; When n is equal to 1, the second injection molding station injects and forms the second layer structure and the third layer structure respectively on both sides of the first layer structure; When n is greater than 1, the second injection molding station to the 2n - 1th injection molding station alternately inject and form the second layer structure to the 2n - 1th layer structure on both sides of the first layer structure in sequence, and the 2nth injection molding station injects and forms the 2nth layer structure and the 2n + 1th layer structure; For the second layer structure to the 2n + 1th layer structure, the cavities for forming even layer structures are located on the movable mold (2), and the cavities for forming odd layer structures are located on the fixed mold (1); When n is equal to 1, the first fixed station and the first movable station inject and form the first layer structure in the central area of the thick-walled plastic part; The second fixed station and the second movable station inject and form the second layer structure connected to one side of the first layer structure, and inject and form the third layer structure connected to the other side of the first layer structure; When n is equal to 2, the first fixed station and the first movable station inject and form the first layer structure in the central area of the thick-walled plastic part; The second fixed station and the second movable station inject and form the second layer structure connected to one side of the first layer structure; The third fixed station and the third movable station inject and form the third layer structure connected to the other side of the first layer structure; The fourth fixed station and the fourth movable station inject and form the fourth layer structure covering the second layer structure, and inject and form the fifth layer structure covering the third layer structure; When n is greater than 2, the first fixed station and the first movable station inject and form the first layer structure in the central area of the thick-walled plastic part; The second fixed station and the second movable station inject and form the second layer structure connected to one side of the first layer structure; The third fixed station and the third movable station inject and form the third layer structure connected to the other side of the first layer structure; The mth fixed station and the mth movable station inject and form the mth layer structure covering the m - 2th layer structure; the m + 1th fixed station and the m + 1th movable station inject and form the m + 1th layer structure covering the m - 1th layer structure; m is an even number greater than or equal to 4 and less than 2n; The 2n-th fixed station and the 2n-th workable station are injection-molded to form the 2n-th layer structure covering the 2n - 2 layer structure, and are injection-molded to form the 2n + 1-th layer structure covering the 2n - 1 layer structure; The cavity for forming the second layer structure is located on the workable station; the cavity for forming the third layer structure is located on the fixed station; The cavity for forming the m-th layer structure is located on the workable station; the cavity for forming the m + 1-th layer structure is located on the fixed station; The cavity for forming the 2n-th layer structure is located on the workable station, and the cavity for forming the 2n + 1-th layer structure is located on the fixed station.

2. The multi-layer injection molding device for thick-walled plastic parts according to claim 1, characterized in that, The moving assembly includes: a driving assembly and a rotatable arm (3) built-in on the movable side; The driving assembly and the rotatable arm (3) built-in on the movable side are located within the area surrounded by 2n workable stations, and the driving assembly drives the rotatable arm (3) built-in on the movable side to rotate; One end of the rotatable arm (3) built-in on the movable side is connected to the driving assembly, and the other end of the rotatable arm (3) built-in on the movable side can move the workpiece injection-molded at the previous injection molding station to the next injection molding station.

3. The multi-layer injection molding device for thick-walled plastic parts according to claim 2, characterized in that, When the rotatable arm (3) built-in on the movable side reaches the first fixed station and the first workable station, the other end of the rotatable arm (3) built-in on the movable side can be located within the injection cavity formed by the first fixed station and the first workable station; The first layer structure injection-molded by the first fixed station and the first workable station can be fixed on the rotatable arm (3) built-in on the movable side.

4. The multi-layer injection molding device for thick-walled plastic parts according to claim 3, characterized in that, A pin is provided at the other end of the rotatable arm (3) built-in on the movable side, and the pin is used to fix the first layer structure; And / or, the heat of the first layer structure can be transferred out through the rotatable arm (3) built-in on the movable side.

5. The multi-layer injection molding device for thick-walled plastic parts according to claim 1, characterized in that, The injection runner for injection-molding the first layer structure is the first runner; The injection runner for injection-molding the j + 1-th layer structure is the j + 1-th runner, and the injection runner for injection-molding the j + 2-th layer structure is the j + 2-th runner. The j + 1-th runner and the j + 2-th runner are respectively arranged on both sides of the first runner. The j + 1-th runner is located on the movable side, and the j + 2-th runner is located on the fixed side; j is an odd number greater than or equal to 1 and less than 2n + 1; All even-numbered runners are arranged in one or more layers on the movable side of the first runner. Each layer contains at least two even-numbered runners. The multiple even-numbered runners in each layer are arranged along the width direction of the first runner, and the width of the first runner can cover the width of the multiple even-numbered runners in each layer; when arranged in multiple layers, the multiple layers of even-numbered runners are arranged in sequence along the movable side direction; All odd-numbered runners are arranged in one or more layers on the fixed side of the first runner. Each layer contains at least two odd-numbered runners. The multiple odd-numbered runners in each layer are arranged along the width direction of the first runner, and the width of the first runner can cover the width of the multiple odd-numbered runners in each layer; when arranged in multiple layers, the multiple layers of odd-numbered runners are arranged in sequence along the fixed side direction.

6. The multi-layer injection molding device for thick-walled plastic parts according to claim 5, characterized in that, The width and thickness of the first runner are the largest among all the runners; And / or, a plurality of flow channels in each layer are distributed from both sides to the center in sequence along the width direction of the first flow channel; And / or, when n is odd, the number of flow channels provided in each layer is odd; When n is even and its factors do not include odd numbers greater than 1, the number of flow channels provided in each layer is even; when n is even and its factors include odd numbers greater than 1, the number of flow channels provided in each layer is even or odd.

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