CN118082092A

CN118082092A - In-mold compression molding die and molding method for thick-wall part of car lamp

Info

Publication number: CN118082092A
Application number: CN202410280247.7A
Authority: CN
Inventors: 吴瑞清
Original assignee: Dongguan Xiongyou Mould Plastic Co ltd
Current assignee: Dongguan Xiongyou Mould Plastic Co ltd
Priority date: 2024-03-12
Filing date: 2024-03-12
Publication date: 2024-05-28

Abstract

The invention discloses an in-mold compression molding die and a molding method for a car light thick-wall part, wherein the in-mold compression molding die comprises a fixed die which is arranged on one side and is connected with an injection molding machine, and a middle movable die which is connected in a sliding way is arranged on one side of the fixed die; a side movable die in sliding connection is arranged on one side of the middle movable die; the fixed die is provided with a first fixed die plate, one side of the middle movable die, corresponding to the first fixed die plate, is provided with a first floating plate, and the first fixed die plate and the first floating plate are matched to form a first cavity with variable internal volume; the side movable mould is provided with a second fixed mould plate, one side of the middle movable mould, corresponding to the second fixed mould plate, is provided with a second floating plate, and the second fixed mould plate and the second floating plate are matched to form a second cavity with variable internal volume; the thick-wall parts of the car lamp are injection molded in the first cavity and the second cavity; the invention completes injection molding of another product while cooling the product in the cavity; meanwhile, the in-mold compression molding is adopted, so that the transmittance of the car light thick-wall part is better.

Description

In-mold compression molding die and molding method for thick-wall part of car lamp

Technical Field

The invention relates to the field of in-mold extrusion forming dies, in particular to an in-mold extrusion forming die and a forming method for a thick-wall part of a car lamp.

Background

The car light generally includes lamp shade, car light thick wall spare, LED lamp and PCB board, and car light thick wall spare is used for the light that the conduction LED lamp sent to derive the lamp shade with light. At present, the thick-wall part of the car lamp becomes a popular lighting mode at present by the uniform lighting effect and the static crystal clear high-quality texture.

In addition, the existing mould for producing the car light thick-wall part by injection molding is generally composed of an upper mould, a lower mould and an ejection mechanism, which are all single and matched with each other, and the mould is opened, ejected, closed, injected, pressure-maintained and cooled; the screw rod is plasticized and idled from idle, forward, stop and backward; the molding cycle time is longer, resulting in lower injection efficiency; meanwhile, the thick-wall part of the car lamp adopts a common injection molding pressure-maintaining forming process, and has the defects of reduction, flow marks and the like on the thick-wall part of the car lamp, which influence the smoothness and transparency of the product and have poor product quality.

Disclosure of Invention

The invention aims to overcome the defects of low production efficiency and poor light transmittance in the prior art and provides an in-mold compression molding die and a molding method for a thick-wall part of a car lamp; and when the product in the cavity is cooled, injection molding of another product is finished, the service efficiency of the equipment is improved, and meanwhile, the in-mold compression molding is adopted, so that the transmittance of the thick-wall part of the car lamp is better.

In order to achieve the above purpose, the invention provides an in-mold compression molding die for a car light thick-wall part, which comprises a fixed die arranged on one side, wherein the fixed die is connected with an injection molding machine, and one side of the fixed die is provided with a middle movable die in sliding connection; a side movable die in sliding connection is arranged on one side of the middle movable die; the fixed die is provided with a first fixed die plate, one side of the middle movable die corresponding to the first fixed die plate is provided with a first floating plate, and the first fixed die plate and the first floating plate are matched to form a first cavity with variable internal volume; the side movable mould is provided with a second fixed mould plate, one side of the middle movable mould corresponding to the second fixed mould plate is provided with a second floating plate, and the second fixed mould plate and the second floating plate are matched to form a second cavity with variable internal volume; and thick-wall parts of the car lamp are injection molded in the first cavity and the second cavity.

Preferably, the fixed die is provided with a glue inlet and a main runner connected with the glue inlet; the main runner extends to the middle movable mould; the middle movable mould is provided with a middle runner vertically connected with the main runner; one side of the middle runner is connected with a first side runner communicated with the first cavity, and the other side of the middle runner is connected with a second side runner communicated with the second cavity.

Preferably, a first needle valve for controlling the communication between the main runner and the middle runner is arranged at the joint of the main runner and the middle runner; the joint of the first side runner and the first cavity is provided with a second needle valve for controlling the first side runner to be communicated with the first cavity; and a third needle valve for controlling the second side runner to be communicated with the second cavity is arranged at the joint of the second side runner and the second cavity.

Preferably, the first side flow passage is provided inside the second needle valve, and the second side flow passage is provided inside the third needle valve.

Preferably, the fixed die and the side movable die are provided with a plurality of guide posts, two sides of the middle movable die are provided with insertion holes corresponding to the guide posts, and the guide posts are inserted into the insertion holes and are in sliding connection with the insertion holes.

Preferably, the first fixed template is fixedly arranged on the first fixed plate, the first floating plate is connected with the first oil cylinder, the first oil cylinder is arranged on the second fixed plate on one side of the first fixed plate, and the first oil cylinder drives the first floating plate to change the internal volume of the first cavity.

Preferably, the second fixed die plate is fixedly arranged on the third fixed plate, the second floating plate is connected with the second oil cylinder, the second oil cylinder is arranged on the fourth fixed plate on one side of the third fixed plate, and the second oil cylinder drives the second floating plate to change the internal volume of the second cavity.

Preferably, an ejector device is arranged on one side of the first fixed template or the second fixed template, and comprises a plurality of ejector rods and a linear driving piece in transmission connection with the ejector rods; the ejector rod penetrates through the first fixed die plate or the second fixed die plate and is inserted into the first cavity or the second cavity, and the linear driving piece drives the ejector rod to eject the car light thick-wall piece.

Preferably, the ejector rods are uniformly distributed around the side edges of the first fixed template or the second fixed template; the first fixed template or the second fixed template is also connected with a cooling water pipe, and the cooling water pipe is connected with an annular pipeline inside the first fixed template or the second fixed template.

The invention also provides an in-mold compression molding method of the car light thick-wall part, which comprises the following steps:

step S1: the middle movable die and the fixed die are matched; the first fixed template is matched with the first floating plate to form a first cavity;

step S2: the first floating plate is far away from the first cavity; after the first cavity is filled with plastic, the first floating plate approaches the first cavity to extrude and cool the plastic in the first cavity; simultaneously, opening the middle movable mould and the side movable mould; ejecting a car light thick-wall part of the second cavity;

Step S3: the middle movable die and the side movable die are matched; the second fixed die plate is matched with the second floating plate to form a second die cavity;

Step S4: the second floating plate is far away from the second cavity; the plastic flows into the second cavity, and after the second cavity is filled with the plastic, the second floating plate is close to the second cavity to extrude and cool the plastic in the second cavity; simultaneously, opening the middle movable mould and the fixed mould; and (5) ejecting the car light thick-wall part of the first cavity.

Compared with the prior art, the invention has the beneficial effects that:

1. The invention is provided with a fixed die connected with an injection molding machine, and one side of the fixed die is provided with a middle movable die in sliding connection; a side movable die in sliding connection is arranged on one side of the middle movable die; the middle movable die is respectively matched with the fixed die and the side movable die at two sides to form a first cavity and a second cavity, and the thick-wall part of the car lamp is cooled in the first cavity and simultaneously the injection of the second cavity is completed, so that waiting time is shortened, and the use efficiency of the equipment is improved; the heating time of the injection molding machine is shortened, and the thermal stability of the plastic is improved, so that the product quality is indirectly improved.

2. According to the invention, after the molten plastic raw material is filled in the first cavity or the second cavity, the first floating plate or the second floating plate is used for extruding the molten plastic raw material, so that the thick-wall part of the car lamp is finally formed, then the car lamp is opened, the thick-wall part of the car lamp is taken out by using the sucking disc, and after the whole production process is finished, the thick-wall part of the car lamp is subjected to compression molding in the mould, no reduction, flow mark and the like exist in the thick-wall part of the car lamp, so that the smoothness and the transmittance of the thick-wall part of the car lamp are improved, the quality is good, and the grade is high.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic view of a thick-walled member for a vehicle lamp according to the present invention;

FIG. 2 is a schematic diagram of an in-mold compression molding die for a thick-walled vehicle lamp member according to the present invention;

FIG. 3 is a schematic view of the internal flow path of an in-mold compression molding die for a thick-walled automotive lamp member according to the present invention;

FIG. 4 is an exploded view of a first cavity provided by the present invention;

FIG. 5 is a schematic side view of an intermediate movable mold according to the present invention;

FIG. 6 is a schematic view of the internal structure of the intermediate movable mold provided by the invention;

FIG. 7 is a schematic view of a second cavity provided by the present invention;

FIG. 8 is a schematic diagram of a side movable mold according to the present invention;

FIG. 9 is another schematic side view of the intermediate movable mold according to the present invention;

fig. 10 is an exploded schematic view of the intermediate movable mold ejector lamp thick-wall member provided by the invention.

The drawings include:

1. A fixed mold; 2. a middle movable mould; 3. a side movable die; 11. a first fixed template; 21. a first floating plate; 5. a first cavity; 31. a second stationary platen; 22. a second floating plate; 6. a second cavity; 4. a thick-walled member for a vehicle lamp; 12. a glue inlet; 13. a main flow passage; 14. an intermediate flow passage; 15. a first side flow passage; 16. a second side flow passage; 71. a first needle valve; 72. a second needle valve; 73. a third needle valve; 61. a guide post; 62. an insertion hole; 81. a first fixing plate; 82. a first cylinder; 83. a second fixing plate; 84. a third fixing plate; 85. a second cylinder; 86. a fourth fixing plate; 92. an ejector rod; 93. and a cooling water pipe.

Detailed Description

The technical solutions of the present embodiment of the present invention will be clearly and completely described below with reference to the drawings in the present embodiment of the present invention, and it is apparent that the described present embodiment is one embodiment of the present invention, but not all the present embodiments. All other embodiments, which can be made by those skilled in the art without making any inventive effort, are intended to be within the scope of the present invention.

Example 1

Referring to fig. 1 to 10, a first embodiment provides an in-mold compression molding mold for a thick-walled vehicle lamp.

As shown in fig. 1, the in-mold compression molding mold includes three parts, the first part is: a fixed die 1 connected with the injection molding machine; in general, the fixed die 1 is fixedly connected with the injection molding machine, so that stable connection is formed, and molten plastic is conveniently input into the die; the second part is: the middle movable die 2 is arranged in the middle and is in sliding connection with the fixed die 1; the third part is: a side movable die 3 arranged on one side of the middle movable die 2 and connected in a sliding manner; the middle movable die 2 can be respectively matched with the fixed die 1 or the side movable die 3; further, the structures of the fixed mold 1 and the side movable mold 3 are substantially similar; furthermore, the middle movable die 2 is respectively matched with the fixed die 1 and the side movable die 3 at two sides to form a first cavity 5 and a second cavity 6, and the thick-wall part 4 of the car lamp completes injection of the second cavity 6 while the first cavity 5 is cooled, so that waiting time is shortened, and the use efficiency of equipment is improved; the heating time of the injection molding machine is shortened, the plastic raw material can be timely injected, and the thermal stability of the plastic is improved, so that the product quality is indirectly improved.

As shown in fig. 4, a first fixed mold plate 11 is disposed on the fixed mold 1, a first floating plate 21 is disposed on a side of the middle movable mold 2 corresponding to the first fixed mold plate 11, and the first fixed mold plate 11 and the first floating plate 21 cooperate to form a first cavity 5 with a variable internal volume.

As shown in fig. 7, the side moving mold 3 is provided with a second fixed mold plate 31, one side of the middle moving mold 2 corresponding to the second fixed mold plate 31 is provided with a second floating plate 22, and the second fixed mold plate 31 and the second floating plate 22 cooperate to form a second cavity 6 with a variable internal volume.

As shown in fig. 10, the thick-wall lamp 4 is injection molded in the first cavity 5 and the second cavity 6.

Before the first cavity 5 or the second cavity 6 is injected, the first floating plate 21 is far away from the first cavity 5, so that the volume inside the first cavity 5 is larger than that of the thick-wall part 4 of the car lamp; the second floating plate 22 is far away from the second cavity 6, so that the volume inside the second cavity 6 is also larger than the thick-wall part 4 of the car light; so that the first cavity 5 or the second cavity 6 can accommodate more plastic, while the first cavity 5 or the second cavity 6 can be filled with plastic with less force, thereby reducing a lot of energy loss.

Further, after the first cavity 5 or the second cavity 6 is filled with the molten plastic raw material, the first floating plate 21 or the second floating plate 22 extrudes the molten plastic raw material inwards, so that the whole cavity can be filled with the plastic raw material, and the density of the plastic in the cavity is higher and tighter; thereby reducing the presence of internal air bubbles; the internal pressure of the cavity is uniform; after cooling, finally form car light thick-wall spare 4, then open the mould, car light thick-wall spare 4 is released to take out car light thick-wall spare 4 with the sucking disc, accomplish car light thick-wall spare 4 of this scheme of whole production process after through the in-mould compression shaping, car light thick-wall spare 4's inside does not have reduction and flow mark etc. has improved car light thick-wall spare 4's smoothness and transmittance, and is of high quality, and the grade is high.

As shown in fig. 2 and 3; the fixed die 1 is provided with a glue inlet 12 and a main runner 13 connected with the glue inlet 12; the main runner 13 extends to the middle movable die 2; the middle movable mould 2 is provided with a middle runner 14 which is vertically connected with the main runner 13; in the present embodiment, the middle runner 14 divides the main runner 13 into two parts; in other embodiments, the middle runner 14 may divide the main runner 13 into three or four; thereby increasing the quantity of injection products and improving the injection efficiency.

Similarly, as shown in fig. 3, two ends of the middle runner 14 are connected to the right with an upper side runner and a lower side runner 15, and the first side runners 15 on the middle movable mold 2 are matched with the fixed mold 1 and are communicated with the first cavity 5; further, two upper and lower second side runners 16 are connected to the left at two ends of the middle runner 14, and the second side runners 16 on the middle movable mold 2 are matched with the side movable mold 3 and are communicated with the second cavity 6. Thus, in this embodiment, four glue injection ports are provided in one cycle, and two first cavities 5 and two second cavities 6 are provided; further, two car light thick-wall parts 4 are injection molded in one cavity.

As shown in fig. 3, in general, in order to control the plastic, so as to perform sequential injection molding, a second needle valve 72 is disposed at the connection between the first side runner 15 and the first cavity 5, for controlling the communication between the first side runner 15 and the first cavity 5; a third needle valve 73 for controlling the second side runner 16 to be communicated with the second cavity 6 is arranged at the joint of the second side runner 16 and the second cavity 6; however, for better controlling the plastic, the orderly output and the connection can be achieved, and a first needle valve 71 for controlling the communication between the main runner 13 and the middle runner 14 can be arranged at the joint of the main runner 13 and the middle runner 14; thereby disconnecting the main runner 13 from the intermediate runner 14, thereby preventing leakage of plastic and achieving orderly control.

Further, the first needle valve 71, the second needle valve 72 and the third needle valve 73 may be controlled by high-pressure gas in cooperation with solenoid valves.

Further, for convenience of control, the first side flow passage 15 may be installed inside the second needle valve 72, and the second side flow passage 16 may be installed inside the third needle valve 73; thereby controlling the opening and closing of the second needle valve 72 and the third needle valve 73 through the on-off of the high-pressure gas, thereby indirectly controlling the on-off of the first side flow passage 15 and the second side flow passage 16; thus, the control is more convenient, and the control efficiency and control precision are improved.

As shown in fig. 8, four guide posts 61 are installed around the side moving mold 3, and similarly, four guide posts 61 are installed on the fixed mold 1; as shown in fig. 5, insertion holes 62 corresponding to the guide posts 61 are provided on both sides of the intermediate movable mold 2; correspondingly, the guide post 61 on the fixed mold 1 is inserted into the insertion hole 62 on the middle moving mold 2, the guide post 61 on the side moving mold 3 is also inserted into the insertion hole 62 on the middle moving mold 2, and in general, the guide post 61 is slidably connected with the insertion hole 62; thereby realizing the die assembly or die opening of the fixed die 1 and the middle movable die 2; and the middle movable die 2 and the side movable die 3 are closed or opened.

As shown in fig. 5, in this embodiment, two identical first cavities 5 are provided, and the first cavities 5 may be placed vertically, horizontally, or obliquely according to actual practice; as shown in fig. 4 and 5, the first fixed mold plate 11 is fixedly mounted on the first fixed plate 81, the first floating plate 21 is connected with the first oil cylinder 82, the first oil cylinder 82 is mounted on the second fixed plate 83 on one side of the first fixed plate 81, the first oil cylinder 82 penetrates through the second fixed plate 83 to extend into the first cavity 5, and the first oil cylinder 82 drives the first floating plate 21 to change the internal volume of the first cavity 5. Further, the second needle valve 72 is also installed in the middle of the second fixing plate 83, and when the internal volume of the first cavity 5 is required to be increased, the first oil cylinder 82 drives the first floating plate 21 to be far away from the first cavity 5; when the internal volume of the first cavity 5 is required to be reduced, the first oil cylinder 82 drives the first floating plate 21 to approach the first cavity 5; in this embodiment, the first oil cylinder 82 drives the first floating plate 21 to reciprocate, and in other embodiments, the power of the first floating plate 21 may be other mechanical force, for example, a cylinder driving force or a micro motor driving force.

Similarly, two second cavities 6 are provided, and the principle is the same as that of the first cavity 5, and the mechanical structure is the same.

As shown in fig. 8, in the present embodiment, two identical second cavities 6 are provided, and the second cavities 6 may be placed vertically, horizontally or obliquely according to actual practice; as shown in fig. 7, the second fixed platen 31 is fixedly mounted on the third fixed platen 84, the second floating platen 22 is connected with the second oil cylinder 85, the second oil cylinder 85 is mounted on the fourth fixed platen 86 on one side of the third fixed platen 84, the second oil cylinder 85 passes through the fourth fixed platen 86 and extends into the second cavity 6, and the second oil cylinder 85 drives the second floating platen 22 to change the internal volume of the second cavity 6. Further, the third needle valve 73 is also installed in the middle of the fourth fixing plate 86, and when the internal volume of the second cavity 6 is required to be increased, the second oil cylinder 85 drives the second floating plate 22 to be far away from the second cavity 6; when the internal volume of the second cavity 6 is required to be reduced, the second oil cylinder 85 drives the second floating plate 22 to be close to the second cavity 6; in this embodiment, the second oil cylinder 85 drives the second floating plate 22 to reciprocate, and in other embodiments, the power of the second floating plate 22 may be other mechanical force, for example, a cylinder driving force or a micro motor driving force.

As shown in fig. 4 and 7, an ejector is mounted on one side of the first fixed platen 11 or the second fixed platen 31, and the ejector ejects the thick-wall member 4 of the vehicle lamp, thereby facilitating the suction of the vacuum chuck.

Specifically, the ejector device comprises a plurality of ejector rods 92 and a linear driving member in transmission connection with the ejector rods 92; the linear driving member may be a cylinder or other linear motion assembly; the ejector rod 92 is inserted into the first cavity 5 or the second cavity 6 through the first fixed die plate 11 or the second fixed die plate 31, and the linear driving member drives the ejector rod 92 to eject the car light thick-wall member 4.

Further, the ejector rods 92 are uniformly distributed around the side edge of the first fixed mold plate 11 or the second fixed mold plate 31; the two sides of the car light thick-wall member 4 are ejected, and in order to adapt to different products, the ejection rod 92 can be additionally arranged or otherwise arranged.

In order to rapidly cool the thick-wall part 4 of the vehicle lamp, the first fixed mold plate 11 or the second fixed mold plate 31 is further connected with a cooling water pipe 93, and the cooling water pipe 93 is connected with an annular pipeline inside the first fixed mold plate 11 or the second fixed mold plate 31.

In other embodiments, if the main runner 13, the middle runner 14, the first side runner 15 and the second side runner 16 of the middle movable mold 2 need to be kept at the same temperature, a heating rod or a heating wire which is uniformly heated can be arranged on the middle movable mold 2, so that the plastics are prevented from being cooled on the runners, the temperature of the plastics is kept consistent, and the molten state is also kept; better flows into the first cavity 5 and the second cavity 6.

Example two

Referring to fig. 1 to 10, a second embodiment provides an in-mold compression molding method for a thick-walled member of a vehicle lamp.

The in-mold compression molding mold is used for splicing 2 sets of molds together, the molds are installed on an injection molding machine for simultaneous production, and the injection molding of products in one set of mold cavities is completed while the products in the other set of mold cavities are cooled. In one cycle period, the injection molding machine needs to plasticize 2 times and inject 2 times, and the cycle is alternated, so that the service efficiency of the equipment is improved to the greatest extent.

Further, the fixed die 1 is fixedly connected with the injection molding machine and is generally immovable; the middle movable die 2 and the side movable die 3 are connected with a transmission mechanism, can horizontally move or vertically move, can independently move and can synchronously move.

Step S1: the middle movable die 2 and the fixed die 1 are matched; the first fixed template 11 is matched with the first floating plate 21 to form a first cavity 5; the time for taking out the thick-wall part 4 of the car light and the time for forming the thick-wall part 4 of the car light are fully utilized by the first cavity 5, so that the plastic in the second cavity 6 is extruded and cooled; thereby improving efficiency.

Step S2: the first floating plate 21 is far away from the first cavity 5; so that the volume inside the first cavity 5 is larger than the thick-wall part 4 of the car light; the injection nozzle of the injection molding machine starts injection molding (plasticizing of the injection molding machine is finished when the upper period is finished), the first needle valve 71 and the second needle valve 72 are opened, plastic flows into the first cavity 5 along the glue inlet 12, the main runner 13, the middle runner 14 and the first side runner 15, after the first cavity 5 is filled with the plastic, the pressure maintaining and cooling stage is carried out, the first floating plate 21 is close to the first cavity 5, and the plastic in the first cavity 5 is extruded and cooled; simultaneously, the car light thick-wall part 4 in the second cavity 6 is subjected to pressure maintaining and cooling, and the middle movable die 2 and the side movable die 3 are opened; a car light thick-wall part 4 of the second cavity 6 is ejected;

Step S3: the middle movable die 2 and the side movable die 3 are matched; the second fixed die plate 31 is matched with the second floating plate 22 to form a second die cavity 6; the time for taking out the thick-wall part 4 of the car light and the time for forming the thick-wall part 4 of the car light are fully utilized by the second cavity 6, so that the plastic in the first cavity 5 is extruded and cooled; thereby improving efficiency.

Step S4: the second floating plate 22 is far away from the second cavity 6; so that the volume inside the second cavity 6 is larger than the thick-wall part 4 of the car light; the injection nozzle of the injection molding machine starts injection molding (plasticizing of the injection molding machine is finished when the upper period is finished), the first needle valve 71 and the third needle valve 73 are opened, plastic flows into the second cavity 6 along the glue inlet 12, the main runner 13, the middle runner 14 and the second side runner 16, after the second cavity 6 is filled with the plastic, the pressure maintaining and cooling stage is carried out, the second floating plate 22 is close to the second cavity 6, and the plastic in the second cavity 6 is extruded and cooled; simultaneously, the car light thick-wall part 4 in the first cavity 5 is subjected to pressure maintaining and cooling, and the middle movable die 2 and the fixed die 1 are opened; the thick-walled lamp part 4 of the first cavity 5 is ejected.

The above examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above examples, and any other changes, modifications, substitutions, combinations, and simplifications that do not depart from the spirit and principle of the present invention should be made in the equivalent manner, and the embodiments are included in the protection scope of the present invention.

Claims

1. An in-mold compression molding die for a thick-wall part of a car lamp is characterized in that: the injection molding machine comprises a fixed mold (1) arranged on one side, wherein the fixed mold (1) is connected with the injection molding machine, and an intermediate movable mold (2) in sliding connection is arranged on one side of the fixed mold (1); a side movable die (3) in sliding connection is arranged on one side of the middle movable die (2); the fixed die (1) is provided with a first fixed die plate (11), one side of the middle movable die (2) corresponding to the first fixed die plate (11) is provided with a first floating plate (21), and the first fixed die plate (11) and the first floating plate (21) are matched to form a first cavity (5) with variable internal volume; a second fixed die plate (31) is arranged on the side movable die (3), a second floating plate (22) is arranged on one side of the middle movable die (2) corresponding to the second fixed die plate (31), and the second fixed die plate (31) and the second floating plate (22) are matched to form a second cavity (6) with the internal volume changed; the first cavity (5) and the second cavity (6) are internally injection-molded with a car light thick-wall part (4).

2. The in-mold compression molding die for a thick-walled member for a vehicle lamp according to claim 1, wherein: the fixed die (1) is provided with a glue inlet (12) and a main runner (13) connected with the glue inlet (12); the main runner (13) extends to the middle movable mould (2); the middle movable mould (2) is provided with a middle runner (14) which is vertically connected with the main runner (13); one side of the middle runner (14) is connected with a first side runner (15) communicated with the first cavity (5), and the other side is connected with a second side runner (16) communicated with the second cavity (6).

3. The in-mold compression molding die for a thick-walled member for a vehicle lamp according to claim 2, wherein: a first needle valve (71) for controlling the communication between the main runner (13) and the middle runner (14) is arranged at the joint of the main runner (13) and the middle runner (14); a second needle valve (72) for controlling the first side runner (15) to be communicated with the first cavity (5) is arranged at the joint of the first side runner (15) and the first cavity (5); and a third needle valve (73) for controlling the second side runner (16) to be communicated with the second cavity (6) is arranged at the joint of the second side runner (16) and the second cavity (6).

4. A vehicle lamp thick-wall member in-mold compression molding die as claimed in claim 3, wherein: the first side flow passage (15) is arranged in the second needle valve (72), and the second side flow passage (16) is arranged in the third needle valve (73).

5. The in-mold compression molding die for a thick-walled member for a vehicle lamp according to claim 1, wherein: the fixed die (1) and the side movable die (3) are provided with a plurality of guide posts (61), two sides of the middle movable die (2) are provided with insertion holes (62) which are matched with the guide posts (61), and the guide posts (61) are inserted into the insertion holes (62) and are in sliding connection with the insertion holes (62).

6. The in-mold compression molding die for a thick-walled member for a vehicle lamp according to claim 1, wherein: the first fixed template (11) is fixedly arranged on the first fixed plate (81), the first floating plate (21) is connected with the first oil cylinder (82), the first oil cylinder (82) is arranged on the second fixed plate (83) on one side of the first fixed plate (81), and the first oil cylinder (82) drives the first floating plate (21) to enable the internal volume of the first cavity (5) to change.

7. The in-mold compression molding die for a thick-walled member for a vehicle lamp according to claim 1, wherein: the second fixed template (31) is fixedly arranged on the third fixed plate (84), the second floating plate (22) is connected with the second oil cylinder (85), the second oil cylinder (85) is arranged on a fourth fixed plate (86) on one side of the third fixed plate (84), and the second oil cylinder (85) drives the second floating plate (22) to enable the internal volume of the second cavity (6) to change.

8. The in-mold compression molding die for a thick-walled member for a vehicle lamp according to claim 1, wherein: an ejector device is arranged on one side of the first fixed die plate (11) or the second fixed die plate (31), and comprises a plurality of ejector rods (92) and a linear driving piece in transmission connection with the ejector rods (92); the ejector rod (92) penetrates through the first fixed die plate (11) or the second fixed die plate (31) to be inserted into the first die cavity (5) or the second die cavity (6), and the linear driving piece drives the ejector rod (92) to eject the car light thick-wall piece (4).

9. The in-mold compression molding die for a thick-walled member for a vehicle lamp according to claim 8, wherein: the ejector rods (92) are uniformly distributed around the side edge of the first fixed template (11) or the second fixed template (31); the first fixed template (11) or the second fixed template (31) is also connected with a cooling water pipe (93), and the cooling water pipe (93) is connected with an annular pipeline inside the first fixed template (11) or the second fixed template (31).

10. An in-mold compression molding method for a thick-wall part of a car lamp is characterized by comprising the following steps of: the method comprises the following steps:

Step S1: the middle movable die (2) and the fixed die (1) are matched; the first fixed template (11) is matched with the first floating plate (21) to form a first cavity (5);

Step S2: the first floating plate (21) is far away from the first cavity (5); the plastic flows into the first cavity (5), and after the first cavity (5) is filled with the plastic, the first floating plate (21) is close to the first cavity (5) to extrude and cool the plastic in the first cavity (5); simultaneously, the middle movable mould (2) and the side movable mould (3) are opened; a car light thick-wall part (4) of the second cavity (6) is ejected;

step S3: the middle movable die (2) and the side movable die (3) are matched; the second fixed die plate (31) is matched with the second floating plate (22) to form a second die cavity (6);

Step S4: the second floating plate (22) is far away from the second cavity (6); the plastic flows into the second cavity (6), and after the second cavity (6) is filled with the plastic, the second floating plate (22) is close to the second cavity (6) to extrude and cool the plastic in the second cavity (6); simultaneously, opening the middle movable mould (2) and the fixed mould (1); and a car light thick-wall part (4) of the first cavity (5) is ejected.