Multi-layer injection molding device for thick-wall plastic part

Abstract

The invention provides a multi-layer injection molding device for a thick-wall plastic part, which is used for forming the thick-wall plastic part divided into 2n + 1 layers through injection molding and comprises a fixed mold and a movable mold, 2n fixed stations are distributed on the fixed mold in the circumferential direction of the fixed mold, and 2n movable stations are arranged on the movable mold in 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, the movable mold is provided with a moving assembly, and the moving assembly can move a workpiece formed by injection molding of the previous injection molding station to the next injection molding station; a first layer structure located in the center area of the thick-wall plastic part is formed in the first injection molding station in an injection molding mode. According to the device disclosed by the invention, through a mode of performing multi-layer injection molding, firstly injecting a core part of a product and then performing layered injection molding on two sides of the product for multiple times, resin of each layer is cooled most sufficiently, and the problem of long molding period is solved.

Description

Technical Field

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

[0002] The typical thickness of the lens of the automotive lighting high and low beam module is usually 25mm or even more than 30mm. When the lens material is resin, the commonly used polymer materials are PC or PMMA. Thick lenses formed by polymer injection molding face 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 thick lenses, the extremely long cooling time greatly affects production efficiency. For large-scale mass-produced cars, a long cycle means low efficiency, which means more investment in molds and molding 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] In view of the defects in the prior art, the object of the present invention is to provide a multi-layer injection molding device for thick-walled plastic parts.

[0004] A multi-layer injection molding device for thick-walled plastic parts provided by the present invention is used for injection molding a thick-walled plastic part divided into 2n+1 layers, comprising: a fixed mold and a movable mold; The fixed mold is provided with 2n fixed stations distributed along its circumference, and the movable mold is provided with 2n movable stations along its circumference; n is a natural number; The 2n fixed stations and the 2n movable stations form 2n injection molding stations, and the movable mold is provided with a moving component, 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 forms a first layer structure located in the center area of ​​the thick-walled plastic part by injection molding; When n is equal to 1, the second injection molding station injects and forms a second layer structure and a 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-1 injection molding station sequentially and alternately inject molds on both sides of the first layer structure to form the second layer structure to the 2n-1 layer structure, and the 2n injection molding station injects molds to form the 2n layer structure and the 2n+1 layer structure; For the second to 2n+1th layer structures, the cavities for forming the even-numbered layer structures are located on the movable mold, and the cavities for forming the odd-numbered layer structures are located on the fixed mold.

[0005] Preferably, when n is equal to 1, the first fixed station and the first movable station are injection molded to form a first layer structure located in the central area of ​​the thick-walled plastic part; The second fixed station and the second movable station are injection molded to form a second layer structure connected to one side of the first layer structure, and the third layer structure is injection molded to form the other side of the first layer structure.

[0006] Preferably, when n is equal to 2, the first fixed station and the first movable station are injection molded to form a first layer structure located in the central area of ​​the thick-walled plastic part; The second fixed station and the second movable station are injection molded to form a second layer structure connected to one side of the first layer structure; The third fixed station and the third movable station are injection molded to form a third layer structure connected to the other side of the first layer structure; The fourth fixed station and the fourth movable station are injection molded to form a fourth layer structure covering the second layer structure, and are injection molded to form a fifth layer structure covering the third layer structure.

[0007] Preferably, when n is greater than 2, the first fixed station and the first movable station are injection molded to form a first layer structure located in the central area of ​​the thick-walled plastic part; The second fixed station and the second movable station are injection molded to form a second layer structure connected to one side of the first layer structure; The third fixed station and the third movable station are injection molded to form a third layer structure connected to the other side of the first layer structure; The mth fixed station and the mth movable station are injection molded to form the mth layer structure covering the m-2th layer structure; the m+1th fixed station and the m+1th movable station are injection molded to 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 2nth fixed station and the 2nth movable station are injection molded to form the 2nth layer structure covering the 2n-2th layer structure, and are injection molded to form the 2n+1th layer structure covering the 2n-1th layer structure.

[0008] Preferably, the cavity for forming the second layer structure is located on the movable station; the cavity for forming the third layer structure is located on the fixed station; The mold cavity for forming the m-th layer structure is located on the movable station; the mold cavity for forming the m+1-th layer structure is located on the fixed station; The mold cavity for forming the 2n-th layer structure is located on the movable station, and the mold cavity for forming the 2n+1-th layer structure is located on the fixed station.

[0009] Preferably, the moving assembly comprises: a driving assembly and a movable side built-in rotating arm; The driving assembly and the movable side built-in rotating arm are located in the area surrounded by the 2n movable stations, and the driving assembly drives the movable side built-in rotating arm to rotate; One end of the movable side built-in rotating arm is connected to the driving assembly, and the other end of the movable side built-in rotating arm can move the workpiece formed by injection molding at the previous injection molding station to the next injection molding station.

[0010] Preferably, when the movable side built-in rotating arm reaches the first fixed station and the first movable station, the other end of the movable side built-in rotating arm can be located in the injection cavity formed by the first fixed station and the first movable station; The first layer structure formed by injection molding at the first fixed station and the first movable station can be fixed on the movable side built-in rotating arm.

[0011] 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; And / or, the heat of the first layer structure can be transferred out through the movable side built-in rotating arm.

[0012] Preferably, the injection channel used for injection molding the first layer structure is a first channel; The injection molding channel used for injection molding the j+1th layer structure is the j+1th channel, and the injection molding channel used for injection molding the j+2th layer structure is the j+2th channel. The j+1th channel and the j+2th channel are respectively arranged on both sides of the first channel, the j+1th channel is located on the movable side, and the j+2th channel is located on the fixed side; j is an odd number greater than or equal to 1 and less than 2n+1; 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, and the multiple even-numbered flow channels of each layer are arranged along the width direction of the first flow channel, and the width of the first flow channel can cover the width of the multiple even-numbered flow channels of each layer; when distributed in multiple layers, the multiple layers of even-numbered flow channels are arranged in sequence along the movable side direction; All odd-numbered channels are distributed in one or more layers on the fixed side of the first channel, each layer contains at least two odd-numbered channels, and the multiple odd-numbered channels of each layer are distributed along the width direction of the first channel, and the width of the first channel can cover the width of the multiple odd-numbered channels of each layer; when distributed in multiple layers, the multiple layers of odd-numbered channels are arranged in sequence along the fixed side direction.

[0013] Preferably, the width and thickness of the first flow channel are the largest among all the flow channels; And / or, the multiple flow channels of each layer are distributed and arranged in sequence from both sides to the center along the width direction of the first flow channel; and / or, when n is an odd number, the number of flow channels provided in each layer is an odd number; When n is an even number and its factor does not include an odd number greater than 1, the number of flow channels set in each layer is an even number; when n is an even number and its factor includes an odd number greater than 1, the number of flow channels set in each layer is an even number or an odd number.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention can realize multi-layer injection molding of thick-walled plastic parts. First, a first layer structure located in the central area of ​​the thick-walled plastic part is formed by the first fixed station and the first movable station, and then a multi-layer structure located on both sides of the first layer structure is alternately formed in sequence by subsequent fixed stations and movable stations, thereby realizing layered injection molding of thick-walled plastic parts, which can greatly reduce the injection molding cycle of thick-walled plastic parts. Taking the aforementioned product with a wall thickness of 25 mm as an example, when it is divided into 7 layers, its molding 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 mode of the flow channel, greatly improves the product quality of layered injection molding, and achieves simultaneous improvement of efficiency and quality.

[0015] 2. The present invention forms the light-emitting surface of the lens at the last station through layered injection molding. The existing light-emitting surface of the lens usually requires processing of complex and expensive microstructure patterns on the injection-molded product. The present invention only forms the last layer of the front and back sides of the product at the last station, so it is only necessary to set the optical microstructure insert at the last station.

[0016] 3. The present invention achieves the goal of producing high-quality lenses with low equipment investment and high efficiency by cleverly dividing the injection molding layers of thick-walled lenses and selecting the injection molding sequence that best conforms to the law of heat transfer. Both PC and PMMA are poor conductors of heat. The thermal conductivity of typical mold steel is about 29w / m2C. Generally speaking, the thermal conductivity of plastic PMMA and PC is not higher than 0.29w / m2C, and the former is 100 times that of the latter. Only by allowing the injected resin to contact the steel more can the heat of the plastic be discharged faster. The present invention first hits the core of the product, allowing the core of the product to cool fully first, and then superimposes the high-temperature resin on the formed part on the front or back of the formed part in turn. This method allows the last injection-molded product to still keep one side of the product in contact with the steel in the 2nd to 5th stations, continuously taking out the product heat, and one side of the newly injection-molded part will continue to contact the mold steel in the next station, continuously taking out the product heat.

[0017] 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 emitting surface. The present invention, through clever design, places the two surfaces with the highest requirements in the last forming station. At this time, the core material of the lens has mostly been fully cooled, and the resin shrinkage is relatively fully compensated in the forming of the first layer. On this basis, the 2nd to 2n+1 layers are injection-molded in sequence, and it is best to inject the 2n and 2n+1 layers at the same time. The resin shrinkage of the previous layer will also be compensated in the injection and pressure holding of the next layer, which makes the forming process more robust, has strong anti-interference ability, and maximizes the forming window. At the same time, the light incident surface and the light emitting surface of the product are formed, and thick-wall injection molding is converted into general thin-wall injection molding, which greatly improves the shape accuracy of the optical lens. Even if the cavity shape of the light incident surface and the light emitting surface needs to be adjusted for some reason, it is only necessary to adjust the corresponding insert of the last station.

[0018] 5. The present invention uses multi-layer injection molding to first inject the core of the product, and then inject the two sides of the product in multiple layers, so that each layer of resin can be fully cooled, solving the problem of long molding cycle. The present invention uses multi-layer injection molding to inject the next layer on the basis of the previously fully cooled product part, so that the shrinkage of the previous layer of the product can be compensated during the injection molding of the next layer. Through injection molding compensation at multiple stations, the lens shape deviation caused by the natural shrinkage of the resin can be minimized. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings: Figure 1 A schematic diagram showing the structure of a fixed station on a fixed mold; Figure 2 A schematic diagram for highlighting the structure of the movable station on the movable mold; Figure 3 A schematic diagram showing the structure of the rotary arm on the movable die; Figure 4 A schematic diagram of the structure to highlight the rotation direction of the spiral arm; Figure 5 A schematic diagram to highlight the formation of the first layer structure; Figure 6 A schematic diagram to highlight the formation of the second layer structure; Figure 7 A schematic diagram to highlight the formation of the third layer structure; Figure 8 A schematic diagram to highlight the formation of the fourth layer structure; Fig. 9 A schematic diagram to highlight the formation of the fifth layer structure; Fig.10 A schematic diagram to highlight the formation of the sixth and seventh layer structures; Fig.11 To highlight the structural diagram of the movable workstation; Fig.12 It is a schematic diagram of the three-dimensional structure of a thick-walled plastic part; Fig.13 It is a schematic diagram of the plane structure of thick-walled plastic parts; Fig.14 for Fig.13 Schematic diagram of the cross-section structure along line BB and line AA; Fig.15 A schematic diagram of the three-dimensional structure of a thick-walled plastic part that drives the injection molding structure in the flow channel; Fig.16 A schematic diagram of the planar structure of a thick-walled plastic part that drives the injection molding structure in the flow channel; Fig.17 for Fig.16 Schematic diagram of the cross-section structure along the CC line; Fig.18 for Fig.16 Schematic diagram of the cross-section structure along line DD; Fig.19 for Fig.16 Schematic diagram of the cross-section structure along line EE; Fig. 20 for Fig.16 Schematic diagram of the cross-section structure along line FF; Fig.21 A schematic diagram of the distribution of the runner injection structure with three runners forming one layer; Fig. 22 A schematic diagram of the distribution of a runner injection structure in which two runners form a layer; Fig.23 This is a schematic diagram of the injection molding process; Fig.24 A flow chart of the steps of a multi-layer injection molding method for thick-walled plastic parts; Fig.25 A schematic diagram showing the thickness h of each layer of the structure; Fig.26 Schematic diagram of simultaneous injection molding of the second layer structure and the third layer structure.

[0020] The figure shows: DETAILED DESCRIPTION

[0021] The present invention is 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 are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0022] Embodiment 1: like Figures 1 to 26 As shown, this embodiment 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, including: a fixed mold 1 and a movable mold 2; the fixed mold 1 is provided with 2n fixed stations distributed along its circumference, and the movable mold 2 is provided with 2n movable stations along its circumference; n is a natural number; the 2n fixed stations and the 2n movable stations form 2n injection molding stations, and the movable mold 2 is provided with a moving component, which 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 a workpiece located at the thick-walled plastic part. The first layer structure of the central area of ​​the 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-1 injection molding station injects alternately on both sides of the first layer structure to form the second layer structure to the 2n-1 layer structure, and the 2n injection molding station injects to form the 2n layer structure and the 2n+1 layer structure; for the second layer structure to the 2n+1 layer structure, the cavity for forming the even-numbered layer structure is located on the movable mold 2, and the cavity for forming the odd-numbered layer structure is located on the fixed mold 1.

[0023] 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 an area surrounded by 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 in the previous injection molding station to the next injection molding station.

[0024] 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 formed by injection molding at the first fixed station and the first movable station can be fixed on the movable side built-in rotating arm 3. A pin is provided 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.

[0025] When n is equal to 1, the first fixed station and the first movable station injection mold to form a 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 to form a second layer structure connected to one side of the first layer structure, and injection mold to form a third layer structure connected to the other side of the first layer structure.

[0026] When n is equal to 2, the first fixed station and the first movable station are injection molded to form a first layer structure located in the central area of ​​the thick-walled plastic part; the second fixed station and the second movable station are injection molded to form a second layer structure connected to one side of the first layer structure; the third fixed station and the third movable station are injection molded to form a third layer structure connected to the other side of the first layer structure; the fourth fixed station and the fourth movable station are injection molded to form a fourth layer structure covering the second layer structure, and a fifth layer structure covering the third layer structure is injection molded.

[0027] When n is greater than 2, the first fixed station and the first movable station are injection molded to form a first layer structure located in the central area of ​​the thick-walled plastic part; the second fixed station and the second movable station are injection molded to form a second layer structure connected to one side of the first layer structure; the third fixed station and the third movable station are injection molded to form a third layer structure connected to the other side of the first layer structure; the mth fixed station and the mth movable station are injection molded to form the mth layer structure covering the m-2th layer structure; the m+1th fixed station and the m+1th movable station are injection molded to 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 2nth fixed station and the 2nth movable station are injection molded to form the 2nth layer structure covering the 2n-2th layer structure, and the 2n+1th layer structure covering the 2n-1th layer structure is injection molded.

[0028] The cavity used to form the second layer structure is located on the movable station; the cavity used to form the third layer structure is located on the fixed station; the cavity used to form the mth layer structure is located on the movable station; the cavity used to form the m+1th layer structure is located on the fixed station; the cavity used to form the 2nth layer structure is located on the movable station, and the cavity used to form the 2n+1th layer structure is located on the fixed station.

[0029] The injection molding channel for injection molding the first layer structure is the first flow channel; the injection molding channel for injection molding the j+1th layer structure is the j+1th flow channel, and the injection molding channel for injection molding the j+2th layer structure is the j+2th flow channel. The j+1th flow channel and the j+2th flow channel are respectively arranged on both sides of the first flow channel, the j+1th flow channel is located on the movable side, and the j+2th flow channel 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 flow channels are distributed in one or more layers on the movable side of the first flow channel, and each layer contains at least two even-numbered flow channels. The multiple even-numbered flow channels of each layer are distributed along the width direction of the first flow channel, and the width of the first flow channel can cover the width of the multiple even-numbered flow channels of each layer; when distributed in multiple layers, the multiple layers of even-numbered flow channels are arranged in sequence along the movable side direction; all odd-numbered flow channels are distributed in one or more layers on the fixed side of the first flow channel, each layer contains at least two odd-numbered flow channels, and the multiple odd-numbered flow channels of each layer are distributed along the width direction of the first flow channel, and the width of the first flow channel can cover the width of the multiple odd-numbered flow channels of each layer; when distributed in multiple layers, the multiple layers of odd-numbered flow channels are arranged in sequence along the fixed side direction.

[0030] The width and thickness of the first flow channel are the largest among all the flow channels. The multiple flow channels of each layer are arranged in a sequential order from both sides to the center along the width direction of the first flow channel; When n is an odd number, the number of flow channels set in each layer is an odd number; when n is an even number and its factor does not include an odd number greater than 1, the number of flow channels set in each layer is an even number; when n is an even number and its factor includes an odd number greater than 1, the number of flow channels set in each layer is an even number or an odd number.

[0031] In this embodiment, 2n workstations are used to complete the injection molding of 2n+1 layers of thick-walled plastic parts.

[0032] In this embodiment, n is 3, 6 fixed stations are arranged along the circumference of the fixed mold 1, and 6 movable stations are arranged along the circumference of the movable mold 2. m is an even number greater than or equal to 4 and less than 2n, so m is 4.

[0033] When m is 4, the 4th fixed station and the 4th movable station are injection molded to form a fourth layer structure connected to the second layer structure; the 5th fixed station and the 5th movable station are injection molded to form a fifth layer structure connected to the third layer structure.

[0034] The sixth fixed station and the sixth movable station are injection molded to form a sixth layer structure and a seventh layer structure respectively connected to the fourth layer structure and the fifth layer structure.

[0035] In other embodiments, if n is 4, m is 4 and 6 respectively; if n is 5, m is 4, 6 and 8 respectively; if n is 6, m is 4, 6, 8 and 10 respectively, and so on.

[0036] A fixed station and a corresponding movable station constitute 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 injection molding station, and the 2n injection molding station.

[0037] In this embodiment, the cavity for forming the first layer structure is located at the fixed station of the first injection molding station, and the cavity for forming the second layer structure is located at the movable station of the second injection molding station; the cavity for forming the third layer structure is located at the fixed station of the third injection molding station; the cavity for forming the fourth layer structure is located at the movable station of the fourth injection molding station; the cavity for forming the fifth layer structure is located at the fixed station of the fifth injection molding station; the cavity for forming the sixth layer structure is located at the movable station of the sixth injection molding station, and the cavity for forming the seventh layer structure is located at the fixed station of the seventh injection molding station.

[0038] The cavity used to form the structure with even layers is on the movable station of the corresponding injection molding station, and the cavity used to form the structure with odd layers is on the fixed station of the corresponding injection molding station.

[0039] In other embodiments, if n is 4, the cavity used to form the 8th layer structure is located on the movable station of the eighth injection molding station, and the cavity used to form the 9th layer structure is located on the fixed station of the ninth injection molding station; if n is 5, the cavity used to form the 10th layer structure is located on the movable station of the tenth injection molding station, and the cavity used to form the 11th layer structure is located on the fixed station of the 11th injection molding station; if n is 6, the cavity used to form the 12th layer structure is located on the movable station of the 12th injection molding station, and the cavity used to form the 13th layer structure is located on the fixed station of the 12th injection molding station, and so on.

[0040] The movable side built-in rotating arms 3 are arranged in sequence along the circumferential direction, and each movable side built-in rotating arm 3 can be moved to the first injection molding station, the second injection molding station, ..., the 2n-1 injection molding station, and the 2n injection molding station in sequence.

[0041] In this embodiment, the number of the movable side built-in rotating arms 3 is set to be the same as the number of the injection molding stations. When performing injection molding, the movable side built-in rotating arms 3 correspond to the injection molding stations one by one. Multiple movable side built-in rotating arms 3 are radially arranged on the driving component, and the driving component drives the multiple movable side built-in rotating arms 3 to rotate simultaneously. In this embodiment, there are six movable side built-in rotating arms 3.

[0042] During injection molding, multiple thick-walled plastic parts are injected at the same time: 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 injection molding of the first layer structure. 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 for 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 for injection molding of the second layer structure, and the third movable side built-in rotating arm 3 moves to the first injection molding station for injection molding of the first layer structure. 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 for 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 for 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 for injection molding of the second layer structure. The fourth movable side built-in rotating arm 3 moves to the first injection molding station for injection molding of the first layer structure. And so on.

[0043] In this embodiment, plastic is injected into the mold of the fixed station and the movable station through an injection structure, and a flow channel for injecting plastic is provided in the injection structure.

[0044] The injection channel used for injection molding the first layer structure is the first channel, which is located in the middle area of ​​the connector structure along the thickness direction. The width and length directions of the first channel are consistent with the length direction of the connector structure, and the width of the first channel is the same as the width of the connector structure.

[0045] 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 structure, so j is 1, 3, and 5 respectively.

[0046] When j is 1, the injection channel used for injection molding of the second layer structure is the second channel, and the injection channel used for injection molding of the third layer structure is the third channel. The third channel and the second channel are respectively arranged on both sides of the first channel, the second channel is located on the movable side, and the third channel is located on the fixed side.

[0047] When j is 3, the injection channel used for injection molding of the fourth layer structure is the 4th channel, and the injection channel used for injection molding of the fifth layer structure is the 5th channel. The 5th channel and the 4th channel are respectively arranged on both sides of the first channel, the 4th channel is located on the movable side, and the 5th channel is located on the fixed side.

[0048] When j is 5, the injection channel used for injection molding of the sixth layer structure is the 6th flow channel, and the injection channel used for injection molding of the seventh layer structure is the 7th flow channel. The 7th flow channel and the 6th flow channel are respectively arranged on both sides of the first flow channel, the 6th flow channel is located on the movable side, and the 7th flow channel is located on the fixed side.

[0049] The injection structure is formed by combining a movable injection structure and a fixed injection structure. The movable injection structure is connected to the movable station, and the fixed injection structure is connected to the fixed station. The even-numbered flow channels are all arranged on the movable injection structure, and the odd-numbered flow channels are all arranged on the fixed injection structure.

[0050] All even-numbered flow channels are arranged in one layer or multiple layers. For multiple flow channels of a single layer, they are distributed and arranged from both sides to the middle in the width direction in sequence. For multiple layers, they are distributed and arranged from the middle to one side in the thickness direction in sequence.

[0051] All odd-numbered flow channels are arranged in one layer or multiple layers. For multiple flow channels of a single layer, they are distributed and arranged from both sides to the middle in the width direction in sequence. For multiple layers, they are distributed and arranged from the middle to one side in the thickness direction in sequence.

[0052] In this embodiment, the second flow channel, the fourth flow channel and the sixth flow channel are arranged in one layer, and the third flow channel, the fifth flow channel and the seventh flow channel are arranged in one layer.

[0053] like Fig. 20 As shown, the second flow channel is arranged at the leftmost area on one side of the first flow channel, the third flow channel is correspondingly arranged at the leftmost area on the other side of the first flow channel, the fourth flow channel is arranged at the rightmost area on one side of the first flow channel, the fifth flow channel is correspondingly arranged at the rightmost area on the other side of the first flow channel, the sixth flow channel is arranged between the second flow channel and the fourth flow channel, and the seventh flow channel is correspondingly arranged between the third flow channel and the fifth flow channel.

[0054] The relationship between the number of layers and n of thick-walled plastic parts is that the number of layers is 2n+1, and the number of runners is the same as the number of layers.

[0055] When n is an odd number, the number of flow channels set in a single layer on one side of the first flow channel is an odd number, for example, when n is 3, 3 flow channels are set in a single layer, when n is 5, 5 flow channels are set in a single layer, when n is 7, 7 flow channels are set in a single layer, and so on.

[0056] When n is an even number and its factors do not include an odd number 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.

[0057] When n is an even number and its factor includes an odd number 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.

[0058] Embodiment 2: Those skilled in the art may understand this embodiment as a more specific description of Embodiment 1.

[0059] This embodiment provides a device and method for high-efficiency and high-quality injection molding of 2n+1 (odd number) layers of thick-walled lenses.

[0060] In this embodiment, the thick-walled plastic part is divided into a 7-layer structure and 6 injection molding stations are provided. In other embodiments, it is not limited to the 7-layer structure and 6 injection molding stations.

[0061] Figure 1 It is a fixed side view, which is a fixed side parting surface view of a monochrome six-station injection molding mold. The figure shows the appearance of the fixed side of the mold, and the positions of the first layer injection point gate 5, the second layer injection point gate 7, the third layer injection point gate 9, the fourth layer injection point gate 11, the fifth layer injection point gate 13, and the seventh layer injection point gate 17 are marked in the figure.

[0062] Among them, the first layer injection point gate 5, the second layer injection point gate 7, the third layer injection point gate 9, the fourth layer injection point gate 11, the fifth layer injection point gate 13 and the seventh layer injection point gate 17 are all injected by the screw on the fixed side to form the required plastic.

[0063] Figure 2 It is a movable side view, showing the movable side parting surface view of the mold, which is the movable side of the injection mold and the outer shape of the movable side of the mold. The position of the sixth layer injection point gate 15 is marked in the figure.

[0064] In this embodiment, the plastic required for molding 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 shot molding by the screw on the fixed side through appropriate flow channel design. In order to ensure the pressure balance of the sixth station, the sixth shot and the seventh shot should be injected at the same time. This can prevent the parts formed in the first to fifth stations from being deformed under the pressure of a single force.

[0065] Figure 3 A movable side view showing the rotating arm. Figure 4 A movable side view showing the direction of movement of the rotating arm.

[0066] like Figures 5 to 10 As shown, the corresponding product parts and shapes formed at each workstation are described.

[0067] Figure 6A movable side view showing product layer two. Figure 7 A movable side view showing product layer three. Figure 8 A movable side view showing product layer four. Fig. 9 A movable side view showing product layer five. Fig.10 A movable side view showing product layer six. Fig.11 A movable side view showing product layer seven.

[0068] like Figure 5 The figure shows a movable side view of the first layer of the product, showing the location of the first layer injection point gate 5. The first layer structure 4 in the figure is the shape formed in the first station. Both sides of the product are in contact with the steel. The SEC AA figure in the upper left corner of the figure is a cross-sectional schematic diagram of the right structure along the AA line.

[0069] like Figure 6 The figure shows the movable side view of the second layer of the product, showing the position of the second layer injection point gate 7. The second layer structure 6 in the figure is the shape formed by the second station, and the cavity is located on the movable side. The SEC BB figure in the lower left corner of the figure is a cross-sectional schematic diagram of the right structure along the BB line.

[0070] like Figure 7 The figure shows the movable side view of the third layer of the product, showing the location of the third layer injection point gate 9. The third layer structure 8 in the figure is the shape formed by the third station, and the cavity is located on the fixed side. The SEC CC figure at the bottom of the figure is a cross-sectional schematic diagram of the upper structure along the CC line.

[0071] like Figure 8 As shown, it is a movable side view showing the fourth layer of the product, showing the location of the fourth layer injection point gate 11. The fourth layer structure 10 in the figure is the shape formed by the fourth station, and the cavity is located on the movable side. The SEC DD figure in the lower right corner of the figure is a cross-sectional schematic diagram of the left structure along the DD line.

[0072] like Fig. 9 As shown, it is a movable side view showing the fifth layer of the product, showing the location of the fifth layer injection point gate 13. The fifth layer structure 12 in the figure is the shape formed in the fifth station, and the cavity is located on the fixed side. The SEC EE diagram in the upper right corner of the figure is a cross-sectional schematic diagram of the left structure along the EE line.

[0073] like Fig.10 As shown, it is a movable side view showing the sixth and seventh product layers, showing the positions of the sixth layer injection point gate 15 and the seventh layer injection point gate 17. The sixth layer structure 14 and the seventh layer structure 16 in the figure correspond to the shapes formed in the sixth station, wherein 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 FF figure in the upper right corner of the figure is a cross-sectional schematic diagram of the lower structure along the EE line.

[0074] Fig.11 A movable side view showing the removal of the product. Fig.12 It is a schematic diagram of the three-dimensional structure of the thick-walled plastic part 25. Fig.13 It is a schematic diagram of the planar structure of the thick-walled plastic part 25.

[0075] Fig.14 The SEC BB diagram on the left is Fig.13 Schematic diagram of the cross section along line BB. Fig.14 The SEC AA diagram on the right is Fig.13 Schematic diagram of the cross section along line AA.

[0076] Fig.15 It is a schematic three-dimensional structural diagram of a thick-walled plastic part 25 with a flow channel injection molding structure 26 formed by a flow channel in the injection structure. Fig.16 It is a schematic plan view of the structure of a thick-walled plastic part 25 with a flow channel injection molding structure 26 formed by a flow channel in the injection structure.

[0077] Fig.17 The SEC CC diagram in Fig.16 The cross-sectional schematic diagram along the CC line shows the first injection molding flow channel 24, the sixth injection molding flow channel 22, and the seventh injection molding flow channel 23.

[0078] Fig.18 The SEC DD diagram is Fig.16 The cross-sectional schematic diagram along the DD line shows the second injection molding flow channel 18 and the third injection molding flow channel 19.

[0079] Fig.19 The SEC EE diagram in Fig.16 The schematic cross-sectional view along line EE shows the fourth injection molding flow channel 20 and the fifth injection molding flow channel 21.

[0080] like Fig. 20 As shown, the gate / runner stacking method cleverly designed to achieve the above-mentioned forming sequence is demonstrated. The first injection molding runner 24 in the figure is a cross section of the runner formed in the first station. The thickness is about 3 to 6 mm and the width is 8 to 15 mm. The second injection molding runner 18 in the figure is a cross section of the runner formed in the second station. The main part of the cold runner is about 2 to 5 mm thick and about 3 to 5 mm wide.

[0081] 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. In order to make it possible to inject glue from the fixed side, a cold runner on the fixed side is designed next to the first injection channel, and the second injection channel on the movable side is partially extended so that the two overlap, thus realizing the connection between the hot gate on the fixed side and the cold runner on the movable side.

[0082] A new side runner structure is added to one side of the structure for forming the runner, and a side runner is formed in the side runner structure to connect the runner on the movable side and guide the gate to the fixed side.

[0083] The third injection molding runner 19 in the figure is the runner section formed at the third station. The thickness is about 2 to 5 mm and the width is about 3 to 5 mm. The fourth injection molding runner 20 in the figure is the runner section formed at the fourth station. The main part of the cold runner is about 2 to 5 mm thick and about 3 to 5 mm wide.

[0084] 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. In order to make it possible to inject glue from the fixed side, a cold runner on the fixed side is designed next to the first injection channel, and the fourth injection channel on the movable side is partially extended so that the two overlap, thus realizing the connection between the hot gate on the fixed side and the cold runner on the movable side.

[0085] A new side runner structure is added to one side of the structure for forming the runner, and a side runner is formed in the side runner structure to connect the runner on the movable side and guide the gate to the fixed side.

[0086] The fifth injection molding flow channel 21 in the figure is the flow channel section formed in the fifth station. The thickness is about 2 to 5 mm and the width is about 3 to 5 mm. The sixth injection molding flow channel 22 and the seventh injection molding flow channel 23 in the figure are the flow channel sections formed in the sixth station. The thickness of the main part is about 2 to 5 mm and the width is about 3 to 5 mm.

[0087] The sixth injection molding flow channel 22 is formed by the screw at the movable side, and the hot gate is directly set in the middle of the flow channel. The seventh injection molding flow channel 23 is formed by the screw at the fixed side, and the hot gate is directly set in the middle of the flow channel.

[0088] Fig. 20 It is the cross-sectional shape of the main part of the cold runner. The first injection molding runner 24 is a runner corresponding to the first layer structure 4. The second injection molding runner 18 is a runner corresponding to the second layer structure 6. The third injection molding runner 19 is a runner corresponding to the third layer structure 8. The fourth injection molding runner 20 is a runner corresponding to the fourth layer structure 10. The fifth injection molding runner 21 is a runner corresponding to the fifth layer structure 12. The sixth injection molding runner 22 is a runner corresponding to the sixth layer structure 14. The seventh injection molding runner 23 is a runner corresponding to the seventh layer structure 16.

[0089] Figure 3 and Figure 4The design of the rotary arm fork for ejecting the product formed in the first station and bringing it to the next station is shown. 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. Two or more pins are set at one end of the built-in rotary arm 3 on the movable side close to the product, extending into the cavity next to the runner body of the first injection molding. The plastic injected from the first station will wrap around the pins. Under the action of the resin contraction force, the molded product will tightly hug the rotary arm. This ensures that the product is firmly fixed on the rotary arm and will not loosen during the process from the first station to the sixth station. After the injection of the sixth station is completed and the product is ejected, the complete product is removed from the rotary arm by a robot or manually.

[0090] In this embodiment, through multi-layer injection molding, the core of the product is first injected, and then the two sides of the product are molded by multiple layers of injection molding, so that each layer of resin can be fully cooled, thereby solving the problem of long molding cycle.

[0091] In this embodiment, through multi-layer injection molding, the next layer is injected on the basis of the previously fully cooled product part, so that the shrinkage of the previous layer of the product is compensated during the injection molding of the next layer. Through injection molding compensation at multiple stations, the lens shape deviation caused by the natural shrinkage of the resin can be minimized.

[0092] In this embodiment, the light-emitting surface of the lens usually needs to be provided with a complex and expensive microstructure pattern, and this design is only used to form the last layer of the front and back of the product at the last station. Therefore, it is only necessary to set the optical microstructure insert at the last station.

[0093] In this embodiment, both PC and PMMA are poor conductors of heat. The thermal conductivity of typical mold steel is about 29w / m2C. Generally speaking, the thermal conductivity of plastic PMMA and PC is no more than 0.29w / m2C. The former is more than 100 times that of the latter. Only by allowing the injected resin to contact the steel more can the heat of the plastic be discharged faster. This design first hits the core of the product, allowing the core of the product to cool fully, and then superimposes the high-temperature resin on the front or back of the formed part in turn. This method allows the product formed by the previous shot to still have one side of the product in contact with the steel in the 2nd to 5th stations, continuously taking out the heat of the product. One side of the newly injection-molded part will continue to contact the mold steel in the next station, continuously taking out the heat of the product.

[0094] In this embodiment, 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 emitting surface. Through clever design, the two surfaces with the highest requirements are formed in the last station. At this time, the core material of the lens has been fully cooled, and the resin shrinkage is fully compensated in the forming of the first layer. On this basis, the light incident surface and the light emitting surface of the product are formed at the same time, and the thick-wall injection molding is converted into general thin-wall injection molding, which greatly improves the shape accuracy of the optical lens. Even if the cavity shape of the light incident surface and the light emitting surface needs to be adjusted for some reason, it is only necessary to adjust the corresponding inserts of the last station.

[0095] The challenges of forming thick-walled injection molded parts are the extremely long forming cycle and the shrinkage that is difficult to compensate. This embodiment cleverly divides the injection molding layers of thick-walled parts, designs the injection molding sequence that best conforms to the law of heat transfer, and combines the multi-layer injection molding method to achieve the goal of efficiently producing low shrinkage and high-precision injection molded thick-walled parts.

[0096] In order to solve the problem of thick-walled plastic parts in injection molding mentioned in the prior art, this embodiment divides the entire product into odd-numbered layers. Fig.14 The figure shows the cross-section of the product in two perpendicular directions when it is divided into 7 layers. Fig.23 The process shows the possible injection molding sequence of the layered design. The first layer structure 4 is injection molded first, and the second layer structure 6 and the third layer structure 8 can be injected simultaneously or sequentially, the fourth layer structure 10 and the fifth layer structure 12 can also be injected simultaneously or sequentially, and the sixth layer structure 14 and the seventh layer structure 16 can also be injected simultaneously or sequentially. The most suitable method can be selected according to the conditions of the equipment.

[0097] The second layer structure 6 and the third layer structure 8 cover the first layer structure. You can freely choose whether to inject the second layer structure 6 or the third layer structure 8 first, as long as the corresponding flow channels and injection ports are provided. If the corresponding flow channels and injection ports are provided, the second layer structure 6 and the third layer structure 8 can be injected at the same time. Fig.26 As shown, when the molding machine has injection barrels on both the fixed side and the movable side, two hot runners can be used to perform injection molding simultaneously from A and B respectively. When the molding machine has an injection barrel only on the fixed side, a runner cavity C can be opened to connect the injection cavities of the second layer structure 6 and the third layer structure 8. In this way, the purpose of simultaneously injecting the second layer structure 6 and the third layer structure 8 can be achieved by only injecting glue from A.

[0098] like Fig.25As shown, 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 20~35mm. 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.

[0099] The wall thickness of the first layer structure 4 needs to be larger than that of other layers, so as to achieve higher injection molding efficiency. In a preferred embodiment, the wall thickness ratio is 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 second layer structure 6, the third layer structure 8, the fourth layer structure 10 and the fifth layer structure 12 of the middle layer, their maximum wall thicknesses are kept equal or at least close. This allows the middle injection molding layer to 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 smaller than the middle layer. The typical range of the sixth layer structure 14 and the seventh layer structure 16 is 1.5~5mm.

[0100] Taking a PMMA product with a wall thickness of 25 mm as an example, the molding cycle can be shortened to 100-150 seconds by using the above seven-layer injection molding method.

[0101] This embodiment uses an odd-numbered layered injection molding method to greatly reduce the molding cycle, improve the surface quality of the plastic part, and meet strict optical requirements.

[0102] The thick-walled injection molded parts innovatively divided into odd layers in this embodiment require appropriate gate design. The clever gate design can maximize the advantages of short multi-layer injection molding cycle and fully compensated shrinkage of plastic parts. This embodiment makes injection molding of plastic parts divided into odd layers possible through clever laminated runner design. At the same time, the compactness of the gate is taken into account, and the gates are gathered in one place to the maximum extent. The subsequent laser cutting of the gate is very convenient. Minimize the residual traces of the gate after cutting.

[0103] Fig.12 The middle part is a thick-walled plastic part. For example, the lens of a car lamp mold has a thickness of 25 to 35 mm. If a plastic part of this thickness is molded in a single layer, the molding cycle can be as long as 20 to 30 minutes or even longer. Multi-layer injection molding, as an alternative to single-layer injection molding, can greatly reduce the molding cycle.

[0104] Taking seven-layer injection molding as an example, the molding cycle can be reduced by about 90%, and the product quality is higher and the optical performance is better. For the 2n+1 (odd number) layered scenario developed for multi-layer injection molding, this embodiment cleverly designs the gates and runners that can adapt to thick-walled plastic parts that are injected layer by layer from the inside out. By using the thickest first injection molding runner 24 as the basis for stacking, the gates and runners corresponding to the subsequent molding layers are superimposed on the back and front of the first injection molding runner, which correspond 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.

[0105] By setting the first injection molding runner 24 to be the widest and thickest, taking the maximum thickness of 25mm and seven-layer injection molding as an example, the gate thickness of the first layer is 3-6mm, and the runner width has a wide range of selection depending on the product size. The goal is to allow the first layer of products to obtain sufficient pressure holding and shrinkage compensation. 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 of the middle layer to be similar in size. The middle layers, which are already similar in thickness, also obtain almost the same pressure holding 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 at the center of the already formed gate runner, because the three sides of the runner are plastic at this time, the heat dissipation speed is far less fast than direct contact with steel, which allows the heat cut-off time of the runner to be postponed as much as possible. Taking the 25mm thick seven-layer injection molding scenario 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 holding window by more than double. The longer pressure holding and shrinkage compensation time window puts the entire plastic part injection molding in a wider molding window, making the injection molding process more robust. The quality of the plastic parts is better and the industrial production is more stable.

[0106] Fig.21 and Fig. 22 The expansion of the gate-runner stack design is shown. Fig.21 It demonstrates the adaptation to 7-layer, 13-layer, 19-layer and other layered injection molding scenarios. Fig.11 The injection molding scenes of adapted plastic parts with 5 layers, 9 layers, 13 layers, etc. are shown.

[0107] This embodiment solves the problem of balanced filling and sufficient pressure maintenance of each layer of an odd-numbered plastic part by cleverly adopting a gate and runner stacking design structure, thereby minimizing the shrinkage of the final product.

[0108] In this embodiment, the gates of multi-layer injection molding are integrated in one place, so that the subsequent gate removal process is simple, the gate residual traces are minimized, and the impact on the appearance is minimized.

[0109] This embodiment widens the pressure holding window of the molding as much as possible by arranging the gate and runner of the last two layers to be formed in the middle of the existing runner, so as to achieve a stable and strong injection molding process and a higher and more stable product quality.

[0110] Embodiment 3: Those skilled in the art may understand this embodiment as a more specific description of Embodiment 1.

[0111] This embodiment achieves the goal of producing high-quality lenses with low equipment investment and high efficiency by cleverly dividing the injection molding layers of thick-walled lenses and selecting the injection molding sequence that best conforms to the law of heat transfer. This embodiment greatly improves the molding efficiency of thick-walled plastic parts by injection molding 2n+1 layers at 2n stations, and achieves the purpose of accurately controlling the dimensions of important shapes by simultaneously injecting the outermost layer on the front and back sides at the last station, which is particularly suitable for the shape control of the light-entry and light-exit surfaces of thick-walled lenses.

[0112] This embodiment takes a thick-walled plastic part mold divided into 7 layers by 6-station injection molding as an example. The 7 layers and 6 stations are just an example of a preferred solution and are not limited to 7 layers.

[0113] The fixed mold 1 is a fixed side of a mold used for injection molding.

[0114] The movable mold 2 is the movable side of the mold used for injection molding. The movable side built-in rotating arm 3 is an electric rotating arm built into the movable mold 2. Figure 4 As shown, the arrow indicates the rotation direction of the spiral arm.

[0115] The first layer structure 4 is a product and a runner formed by injection molding at the first station, and the first layer injection point gate 5 is a point gate of the first layer structure 4 .

[0116] Since the fork pin of the built-in rotating arm 3 on the movable side is cleverly extended into the runner cavity of the first layer structure 4, after the first layer structure 4 is injected and cooled, the first layer structure 4 will be tightly stuck on the fork pin of the built-in rotating arm 3 on the movable side. When the molding machine opens the mold, the built-in rotating arm 3 on the movable side will be ejected from the movable mold and rotated 60 degrees, bringing the first layer structure 4 from the first station to the top of the second station. Then the ejected built-in rotating arm 3 on the movable side returns to the movable mold 2, and at the same time brings the first layer structure 4 into the cavity of the second station. At the second station, the first layer structure 4 will keep in contact with the steel of the fixed mold 1 after the mold is closed, so that the plastic part can continue to dissipate heat efficiently. The cavity of the second layer is mainly on the movable side of the mold. The second layer structure 6 is superimposed 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.

[0117] After the second layer structure 6 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, while the second layer structure 6 is brought into the third station. At the third station, the second layer structure 6 will remain in contact with the steel of the movable mold 2 after the mold is closed, so that the second layer structure 6 can continue to dissipate heat efficiently. The cavity of the third layer is mainly on the fixed side of the mold. The third layer structure 8 is superimposed on the combination 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.

[0118] After the third layer structure 8 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, while bringing the third layer structure 8 into the fourth station. At the fourth station, the third layer structure 8 will remain in contact with the steel of 1 after the mold is closed, so that the third layer structure 8 can continue to dissipate heat efficiently. The cavity of the fourth layer is mainly on the movable side of the mold. The fourth layer structure 10 is superimposed on the combination 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] The above-mentioned forming steps can be extended to the case where 2n (even number) stations form 2n+1 (odd number) layers of thick-walled plastic parts. In this embodiment, 2n (even number) stations are used to form thick-walled plastic parts divided into 2n+1 (odd number) layers of thick-walled plastic parts by injection molding, which greatly improves the forming efficiency of thick-walled plastic parts. In the last station, the outermost layer is injected simultaneously on the front and back sides to achieve the purpose of accurately controlling the dimensions of important shapes, which is particularly suitable for the shape control of the light-entry and light-exit surfaces of thick-walled lenses.

[0123] This embodiment uses a clever mold design to set the outer shell, which has the greatest impact on the product's shape, at the last station, making it 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, the molding parameters of the light-entering layer and the light-exiting layer are controlled separately). The goal of producing high-precision thick-walled parts with low shrinkage is achieved.

[0124] This embodiment solves the problem of heat dissipation difficulty in the core of single-color injection-molded products, long cooling time, and large product shrinkage by first injecting the center of the product and then injecting the front and back layers one by one. It achieves more efficient use of mold steel to cool plastic parts, greatly reduces the molding cycle of plastic parts, and the benefits of large-scale mass production are very obvious.

[0125] This embodiment sets the outer shell, which has the greatest impact on the product surface, at the last station, which greatly eases the machining accuracy requirements of the product cavity at the previous station. If there are scratches or roughness in the cavity at the previous station, it can be fully melted by the high-temperature resin formed by the next layer of stacking, which greatly reduces the pressure of mold maintenance.

[0126] In this embodiment, the shell that has the greatest impact on the product surface is set at the last station, and only the cavity of the last station needs to be processed with high precision, which greatly reduces the processing cost of the mold and the subsequent possible design change cost.

[0127] This embodiment solves the problem of short pressure holding window time and large product shrinkage of single-color injection molded products by first injection molding the center of the product and then stacking injection molding on the front and back sides layer by layer. It achieves the goal of fully holding the plastic parts in each layer and creates a molding condition that allows the next station to compensate for the shrinkage of the plastic parts in the previous station, so that the shrinkage of the final product is low, which is suitable for large-scale mass production of plastic parts with strict precision requirements (such as optical lenses).

[0128] Embodiment 4: Those skilled in the art may understand this embodiment as a more specific description of Embodiment 1.

[0129] like Figures 1 to 26 As shown, this embodiment provides a multi-layer injection molding method for thick-walled plastic parts, comprising the following steps: Layer structure division step: the thick-walled plastic part is divided into 2n+1 layer structures, namely the first layer structure to the 2n+1 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 layer structure are distributed on both sides of the first layer structure; n is a natural number; Multi-layer injection molding step: 2n injection molding stations are set, and the first layer structure to the 2n+1 layer structure of the thick-walled plastic part are sequentially formed by injection molding through the 2n injection molding stations; the first layer structure is formed by injection molding through the first injection molding station; When n is equal to 1, a second layer structure and a third layer structure respectively located on both sides of the first layer structure are formed by injection molding through a second injection molding station; When n is greater than 1, when injection molding is performed through the second injection molding station to the 2n-1 injection molding station, the second layer structure to the 2n-1 layer structure are formed alternately on both sides of the first layer structure; the previous injection molding station injects on one side of the first layer structure to form a layer structure, and the next injection molding station injects at the relative position on the other side of the first layer structure to form another layer structure; the 2n layer structure and the 2n+1 layer structure are formed by injection molding through the 2n injection molding station, and the 2n layer structure and the 2n+1 layer structure form the surface layer structure of the thick-walled plastic part.

[0130] For the second to 2n+1 layer structures, the even-numbered layer structures and the odd-numbered layer structures are alternately formed on both sides of the first layer structure; the next even-numbered layer structure covers the previous even-numbered layer structure, and the next odd-numbered layer structure covers the previous odd-numbered layer structure. For the second to 2n+1 layer structures, the even-numbered layer structures are formed on the movable side of the injection molding station, and the odd-numbered layer structures are formed on the fixed side of the injection molding station.

[0131] The multi-layer injection molding step specifically includes the following steps: Step S1: setting a moving component and 2n injection molding stations, and arranging the 2n injection molding stations so that the moving component can sequentially reach the first injection molding station to the 2nth injection molding station; Step S2: the mobile component arrives at the first injection molding station, the fixed station and the movable station of the first injection molding station are molded together, and the first layer structure is formed by injection molding; Wherein, a connecting 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 connecting structure, and the moving component can drive the first layer structure to move; In step S2, when the first layer structure is injection molded, a portion of the cavity for injection molding the first layer structure is located at the fixed station, and another portion is located at the movable station, and two sides of the first layer structure can be in contact with the fixed station and the movable station for heat conduction respectively; Step S3: opening the mold of the fixed station and the movable station of the first injection molding station, ejecting the first layer structure from the movable station of the first injection molding station by the moving component, and then moving the first layer structure to the movable station of the second injection molding station by the moving component; Step S4: Clamp the fixed station and the movable station of the second injection molding station, and inject on one side of the first layer structure to form a second layer structure connected to the first layer structure; In step S4, when the second layer structure is injection-molded, the cavity for injection-molding the second layer structure is located on the movable station, and the other side of the first layer structure can contact with the fixed station for heat conduction; Step S5: opening the mold of the fixed station and the movable station of the second injection molding station, ejecting the combination of the first layer structure and the second layer structure from the movable station of the second injection molding station by the moving component, and then moving the combination of the first layer structure and the second layer structure to the movable station of the third injection molding station by the moving component; Step S6: Clamp the fixed station and the movable station of the third injection molding station, and inject molding on the other side of the first layer structure to form a third layer structure connected to the first layer structure; In step S6, when the third layer structure is injection-molded, the cavity for injection-molding the third layer structure is located on a fixed station, and the second layer structure can be in contact with the movable station for heat conduction; Step S7: opening the mold of the fixed station and the movable station of the third injection molding station, ejecting the combination of the first layer structure, the second layer structure and the third layer structure from the movable station of the third injection molding station by the moving component, and then moving the combination of the first layer structure, the second layer structure and the third layer structure to the movable station of the fourth injection molding station by the moving component; If n is greater than 2, then step S8 and step S9 are performed in sequence; if n is equal to 2, then step S9 is performed directly; Step S8: Clamp the fixed station and the movable station of the a-th injection molding station, and form the a-th layer structure connected to the a-th layer structure by injection molding on one side of the first layer structure; The fixed station and the movable station of the a-th injection molding station are opened, and the combination formed by injection molding at the a-th injection molding station is ejected from the movable station of the a-th injection molding station by the moving component, and then the combination formed by injection molding at the a-th injection molding station is moved to the movable station of the a+1-th injection molding station by the moving component; The fixed station and the movable station of the a+1th injection molding station are molded together, and the a+1th layer structure connected to the a-1th layer structure is formed by injection molding on the other side of the first layer structure; The fixed station and the movable station of the a+1th injection molding station are opened, and the combination formed by injection molding at the a+1th injection molding station is ejected from the movable station of the a+1th injection molding station by the moving component, and then the combination formed by injection molding at the a+1th injection molding station is moved to the movable station of the a+2th injection molding station by the moving component; a is an even number greater than or equal to 4 and less than 2n, and the fourth to 2n-1th layer structures are sequentially formed through the above steps; In step S8, when the a-th layer structure is injection molded, the cavity for injection molding the a-th layer structure is located on the movable station, and the a-1-th layer structure can be in contact with the fixed station for heat conduction; When the a+1 layer structure is injection molded, the cavity for injection molding the a+1 layer structure is located on a fixed station, and the a layer structure can be in contact with the movable station for heat conduction; Step S9: Clamp the fixed station and the movable station of the 2nth injection molding station, and form a 2nth layer structure connected to the 2n-2th layer structure by injection molding on one side of the first layer structure, and form a 2n+1th layer structure connected to the 2n-1th layer structure by injection molding on the other side of the first layer structure; In step S9, when the 2n-layer structure and the 2n+1-layer structure are injection molded, the cavity for injection molding the 2n-layer structure is located on the movable station, and the cavity for injection molding the 2n+1-layer structure is located on the fixed station; Step 10: Open the mold of the fixed station and the movable station of the 2nth injection molding station, and take out the formed thick-walled plastic parts.

[0132] The moving component is connected to the first layer structure through a built-in rotating arm on the movable side. The built-in rotating arm on the movable side can move the workpiece molded at the previous injection molding station to the next injection molding station. During the entire injection molding process of the thick-walled plastic part, the built-in rotating arm on the movable side can always dissipate the heat accumulated on the first layer structure.

[0133] 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. The two sides of the first layer structure are divided into 3 layer structures, 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; In other embodiments, if n is 4, it is divided into 9 layers, and 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; In this embodiment, 6 injection molding stations are provided, and the first to seventh layer structures of the thick-walled plastic part are sequentially injection-molded by the 6 injection molding stations. When the second to fifth injection molding stations perform injection molding, the second to fifth layer structures are alternately formed on both sides of the first layer structure. After the first injection molding station forms the first layer structure by injection molding, the second injection molding station forms the second layer structure by injection molding on one side of the first layer junction, the third injection molding station forms the third layer structure by injection molding at a relative position on the other side of the first layer junction, the fourth injection molding station forms the fourth layer structure connected to the second layer structure by injection molding on one side of the first layer junction, and the fifth injection molding station forms the fifth layer structure connected to the third layer structure by injection molding at a relative position on the other side of the first layer junction. In this embodiment, the sixth injection molding station forms the sixth and seventh layers of structures, which form the surface layer structure of the thick-walled plastic part. The sixth and seventh layers of structures form the most important structures of the surface layer, and in the lens scenario, correspond to the light incident surface and the light exit surface, which are the two surfaces with the highest requirements on the shape.

[0134] In this embodiment, six injection molding stations are arranged so that the mobile component can reach the first injection molding station to the sixth injection molding station in sequence.

[0135] 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 molded together, and a fourth layer structure connected to the second layer structure is formed by injection molding on one side of the first layer structure; The fixed station and the movable station of the fourth injection molding station are molded, and the combination formed by injection molding at the fourth injection molding station is ejected from the movable station of the fourth injection molding station by the moving component, and then the combination formed by injection molding at the fourth injection molding station is moved to the movable station of the fifth injection molding station by the moving component; the combination is a combination of the first layer structure, the second layer structure, the third layer structure and the fourth layer structure; The fixed station and the movable station of the fifth injection molding station are molded together, and a fifth layer structure connected to the third layer structure is formed by injection molding on the other side of the first layer structure; The fixed station and the movable station of the fifth injection molding station are molded, and the combination formed by injection molding at the fifth injection molding station is ejected from the movable station of the fifth injection molding station by the moving component, and then the combination formed by injection molding at the fifth injection molding station is moved to the movable station of the sixth injection molding station by the moving component; the combination 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; In other embodiments, if n is 4, a is 4 and 6 respectively, forming the fourth to seventh structures respectively; if n is 5, a is 4, 6 and 8 respectively, forming the fourth to ninth structures respectively, and so on.

[0136] When the fourth layer structure is injection molded, the cavity used for injection molding 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 the fifth layer structure is injection molded, the cavity used for injection molding the fifth layer structure is located on the fixed station, and the fourth layer structure can contact and conduct heat with the movable station.

[0137] In this embodiment, the fixed station and the movable station of the sixth injection molding station are molded together, and the sixth layer structure connected to the fourth layer structure is formed by injection molding on one side of the first layer structure, and the seventh layer structure connected to the fifth layer structure is formed by injection molding on the other side of the first layer structure.

[0138] When the sixth and seventh layer structures are injection molded, the cavity for injection molding the sixth layer structure is located on the movable station, and the cavity for injection molding the seventh layer structure is located on the fixed station.

[0139] The fixed station and the movable station of the sixth injection molding station are opened to take out the formed thick-walled plastic parts.

[0140] 2n fixed stations are arranged along the circumference of the fixed mold; 2n movable stations are arranged along the circumference of the movable mold; the fixed stations and the movable stations are arranged one by one, and the 2n fixed stations and the 2n movable stations form 2n injection molding stations; the movable assembly includes a driving assembly and a movable side built-in rotating arm arranged on the movable mold, and the driving assembly and the movable side built-in rotating arm are located in the annular area formed by the 2n movable stations; the driving assembly drives the movable side built-in rotating arm to rotate, and one end of the movable side built-in rotating arm can reach the first injection molding station to the 2nth injection molding station in sequence; one end of the movable side built-in rotating arm forms a connecting structure for fixing the first layer structure, which can drive the first layer structure to rotate; the movable side built-in rotating arm can move the injection molded part of the previous injection molding station to the next injection molding station by rotating. During the entire injection molding process of the thick-walled plastic part, the movable side built-in rotating arm can always extract the heat accumulated on the first layer structure. The connecting structure is provided with a pin for fixing the first layer structure.

[0141] In this embodiment, 6 fixed workstations are distributed along the circumference of the fixed mold; 6 movable workstations are distributed along the circumference of the movable mold; the fixed workstations and the movable workstations are arranged in a one-to-one correspondence, and the 6 fixed workstations and the 6 movable workstations form 6 injection molding workstations.

[0142] The device of the present invention uses multi-layer injection molding to first inject the core of the product and then inject the two sides of the product in multiple layers, so that each layer of resin can be fully cooled, thereby solving the problem of long molding cycle.

[0143] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0144] The above describes the specific embodiments of the present invention. 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. In the absence of 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: Used for injection molding to form a thick-walled plastic part divided into 2n+1 layers, comprising: a fixed mold (1) and a movable mold (2); The fixed mold (1) is provided with 2n fixed workstations distributed along its circumference, and the movable mold (2) is provided with 2n movable workstations distributed along its circumference; n is a natural number; The 2n fixed workstations and the 2n movable workstations form 2n injection molding workstations, and the movable mold (2) is provided with a moving component, and the moving component can move a workpiece injection-molded at a previous injection molding workstation to a next injection molding workstation; The first injection molding station forms a first layer structure located in the center area of ​​the thick-walled plastic part by injection molding; When n is equal to 1, the second injection molding station injects and forms a second layer structure and a 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-1 injection molding station sequentially and alternately inject molds on both sides of the first layer structure to form the second layer structure to the 2n-1 layer structure, and the 2n injection molding station injects molds to form the 2n layer structure and the 2n+1 layer structure; For the second layer structure to the 2n+1th layer structure, the cavity used to form the even-numbered layer structure is located on the movable mold (2), and the cavity used to form the odd-numbered layer structure is located on the fixed mold (1).

2. The multi-layer injection molding device for thick-walled plastic parts according to claim 1, characterized in that: When n is equal to 1, the first fixed station and the first movable station are injection molded to form a first layer structure located in the center area of ​​the thick-walled plastic part; The second fixed station and the second movable station are injection molded to form a second layer structure connected to one side of the first layer structure, and the third layer structure is injection molded to form the other side of the first layer structure.

3. The multi-layer injection molding device for thick-walled plastic parts according to claim 1, characterized in that: When n is equal to 2, the first fixed station and the first movable station are injection molded to form a first layer structure located in the central area of ​​the thick-walled plastic part; The second fixed station and the second movable station are injection molded to form a second layer structure connected to one side of the first layer structure; The third fixed station and the third movable station are injection molded to form a third layer structure connected to the other side of the first layer structure; The fourth fixed station and the fourth movable station are injection molded to form a fourth layer structure covering the second layer structure, and are injection molded to form a fifth layer structure covering the third layer structure.

4. The multi-layer injection molding device for thick-walled plastic parts according to claim 1, characterized in that: When n is greater than 2, the first fixed station and the first movable station are injection molded to form a first layer structure located in the center area of ​​the thick-walled plastic part; The second fixed station and the second movable station are injection molded to form a second layer structure connected to one side of the first layer structure; The third fixed station and the third movable station are injection molded to form a third layer structure connected to the other side of the first layer structure; The mth fixed station and the mth movable station are injection molded to form the mth layer structure covering the m-2th layer structure; the m+1th fixed station and the m+1th movable station are injection molded to 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 2nth fixed station and the 2nth movable station are injection molded to form the 2nth layer structure covering the 2n-2th layer structure, and are injection molded to form the 2n+1th layer structure covering the 2n-1th layer structure.

5. The multi-layer injection molding device for thick-walled plastic parts according to claim 4, characterized in that: The mold cavity for forming the second layer structure is located on the movable station; the mold cavity for forming the third layer structure is located on the fixed station; The mold cavity for forming the m-th layer structure is located on the movable station; the mold cavity for forming the m+1-th layer structure is located on the fixed station; The mold cavity for forming the 2n-th layer structure is located on the movable station, and the mold cavity for forming the 2n+1-th layer structure is located on the fixed station.

6. The multi-layer injection molding device for thick-walled plastic parts according to claim 1, characterized in that: The moving assembly comprises: a driving assembly and a movable side built-in rotating arm (3); The driving assembly and the movable side built-in rotating arm (3) are located in an area surrounded by the 2n movable workstations, and the driving assembly 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 assembly, and the other end of the movable side built-in rotating arm (3) is capable of moving a workpiece injection-molded at a previous injection molding station to a next injection molding station.

7. The multi-layer injection molding device for thick-walled plastic parts according to claim 6, characterized in that: 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 molding cavity formed by the first fixed station and the first movable station; The first layer structure formed by injection molding at the first fixed station and the first movable station can be fixed on the movable side built-in rotating arm (3).

8. The multi-layer injection molding device for thick-walled plastic parts according to claim 7, characterized in that: The other end of the movable side built-in rotating arm (3) is provided with a pin, 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 movable side built-in rotating arm (3).

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

10. The multi-layer injection molding device for thick-walled plastic parts according to claim 9, characterized in that: The width and thickness of the first flow channel are the largest among all the flow channels; And / or, the multiple flow channels of each layer are distributed and arranged in sequence from both sides to the center along the width direction of the first flow channel; and / or, when n is an odd number, the number of flow channels provided in each layer is an odd number; When n is an even number and its factor does not include an odd number greater than 1, the number of flow channels set in each layer is an even number; when n is an even number and its factor includes an odd number greater than 1, the number of flow channels set in each layer is an even number or an odd number.

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