CN220314024U - Injection mold capable of eliminating surface flow marks of plastic part - Google Patents

Abstract

The utility model discloses an injection mold capable of eliminating flow marks on the surface of a plastic part, which comprises a movable mold and a fixed mold, wherein the movable mold and the fixed mold are connected in an openable manner, a product cavity is formed in the joint of the fixed mold and the movable mold, a mold core is arranged in the fixed mold, the mold core can extend into the product cavity, a plurality of inserts are arranged in the mold core, an insert driving mechanism is arranged on the fixed mold and is respectively connected with all inserts, and the insert driving mechanism can drive the inserts to slide in the mold core, so that the upper end faces of all the inserts can be flush with the upper end faces of the mold core. According to the utility model, the sizing material can be injected into the product cavity in two steps, so that the sizing material is prevented from being split and reflowed in the product cavity in the injection molding process, the surface of a plastic product is prevented from forming flow marks, the processing yield is improved, and the processing requirements of high quality and large batch are met.

Description

Injection mold capable of eliminating surface flow marks of plastic part

Technical Field

The utility model relates to the technical field of injection molds, in particular to an injection mold capable of eliminating flow marks on the surface of a plastic part.

Background

Injection molding is the most common processing mode in plastic part processing, and in the traditional plastic part product processing, in order to improve the smoothness and the attractiveness of the surface of a plastic part product, a specific coating is usually sprayed on the surface of the plastic part product after the plastic part is injection molded; the increase of the working procedures inevitably increases the manufacturing cost and reduces the efficiency. In order to solve the problem, spraying-free materials are appeared on the market, injection molding is carried out by using the materials, and the surface of a molded product can achieve the spraying effect.

Fig. 1 and 2 show a charger housing of a home appliance, and the molded article 100 is of a metallic color and has a smooth surface. As shown in fig. 1 and 2, the upper end surface of the plastic product 100 is smooth, and the positioning posts 200 and the screw posts 300 are disposed in the inner cavity, so that corresponding slots must be designed on the product cavity and corresponding positions of the positioning posts 200 and the screw posts 300 in the mold when designing the injection mold of the product.

As shown in fig. 3, when the conventional injection mold is used to process the plastic part, after the injection molding machine injects the liquid glue into the product cavity, the glue is first filled into the upper surface of the product, then the glue is split and flows into the corresponding slots of the positioning posts 200 and the screw posts 300, and after the slots of the positioning posts 200 and the screw posts 300 are filled, the glue again flows into the upper surface of the product, so that the glue forms a confluence on the upper surface of the product, and the arrow direction in fig. 3 is the flow track of the glue in the product cavity. Because the general fluidity of the spraying-free sizing material is poor, after two sizing materials with different flow rates are converged on the upper surface of the product, flow lines can be formed on the upper surface of the product, and poor appearance of the product is caused.

Disclosure of Invention

In order to solve the problems in the prior art, the utility model provides an injection mold capable of eliminating flow marks on the surface of a plastic part, which comprises a movable mold and a fixed mold, wherein the movable mold and the fixed mold are connected in an openable manner, a product cavity is arranged at the joint of the fixed mold and the movable mold, a mold core is arranged in the fixed mold, the mold core can extend into the product cavity, a plurality of inserts are arranged in the mold core, an insert driving mechanism is arranged on the fixed mold and is respectively connected with all inserts, and the insert driving mechanism can drive the inserts to slide in the mold core so as to enable the upper end surfaces of all inserts to be flush with the upper end surface of the mold core.

As a further improvement of the utility model, the insert driving mechanism comprises a driving piece and an insert mounting plate, wherein the driving piece is connected with the fixed die, the output end of the driving piece is connected with the insert mounting plate, and the inserts are respectively connected with the insert mounting plate.

As a further improvement of the utility model, the insert comprises a first insert and a second insert, the first insert and the second insert are respectively connected with the insert mounting plate, the number of the first inserts is the same as the number of the positioning posts on the plastic product, and the number of the second inserts is the same as the number of the screw posts on the plastic product.

As a further improvement of the utility model, a limiting block is sleeved on the first insert, a limiting groove is respectively arranged on the lower end face of the insert mounting plate and at the corresponding position of the first insert, the first insert can slide in the limiting groove, a limiting plate is arranged on the lower end face of the insert mounting plate, the first insert can pass through the limiting plate, and the limiting block can be respectively abutted with the limiting plate and the end face of the limiting groove.

As a further improvement of the utility model, the movable mould is provided with a movable mould core, the product cavity is arranged on the lower end face of the movable mould core, the movable mould core is internally provided with heating pipes, and the heating pipes are distributed on the periphery of the product cavity.

As a further improvement of the utility model, the periphery of the movable mold core is sleeved with the heat insulation plate, and the heat insulation plate is respectively abutted with the peripheral outer side wall and the upper end face of the movable mold core.

As a further improvement of the utility model, hollow grooves are respectively arranged on the outer side wall and the upper end face of the movable mold core, bumps are respectively arranged at the positions corresponding to the hollow grooves on the heat insulation plate, the bumps are adapted to the corresponding hollow grooves, and the bumps are inserted into the corresponding hollow grooves for limiting connection.

As a further improvement of the utility model, cooling water pipes are respectively arranged in the movable mold and the fixed mold, the cooling water pipes are respectively distributed on the periphery of the mold core and the movable mold core, water inlet connectors and water outlet connectors are respectively arranged on the outer side walls of the movable mold and the fixed mold, and the water inlet connectors and the water outlet connectors are respectively communicated with the corresponding cooling water pipes.

As a further improvement of the utility model, the number of the product cavities is two, and the connecting part of the fixed die and the movable die is provided with flow channels which are respectively communicated with the two product cavities.

As a further improvement of the utility model, a plurality of positioning grooves are arranged on the lower end surface of the movable die, positioning blocks are respectively arranged at the positions corresponding to the positioning grooves on the fixed die, and the positioning blocks are detachably clamped with the corresponding positioning grooves.

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

according to the utility model, the insert and the insert driving mechanism are arranged in the fixed die, so that the upper end face of a product can be controlled to be filled with rubber material in the injection molding process, and then the slots corresponding to the positioning column and the screw column are refilled; injecting sizing material into the product cavity in two steps can avoid the sizing material from being shunted and then reflowed in the product cavity in the injection molding process, so that the surface of a plastic part can be prevented from forming flow marks, the processing yield is improved, and the processing requirements of high quality and large batch are met.

During specific injection molding, the insert is driven to move upwards in the die core through the insert driving mechanism, so that the upper end faces of the inserts are respectively flush with the upper end faces of the die core, and the insert temporarily blocks the slots corresponding to the positioning columns and the screw columns; at the moment, glue stock is injected into the product cavity, and the glue stock can flow through the plane without diversion and confluence, so that no flow lines are generated. After the upper end face of the product is completely filled, driving the insert to move downwards through the insert driving mechanism, so that the insert is respectively retracted into the die core to expose the corresponding slotted holes of the positioning column and the screw column, and the sizing material can continuously flow into the corresponding slotted holes of the positioning column and the screw column to fill the positioning column and the screw column; and finally, cooling and forming to finish injection molding of a product.

Drawings

In order to more clearly illustrate the utility model or the solutions of the prior art, a brief description will be given below of the drawings used in the description of the embodiments or the prior art, it being obvious that the drawings in the description below are some embodiments of the utility model and that other drawings can be obtained from them without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a product structure processed by an embodiment of the utility model;

FIG. 2 is a schematic view of another view of a product manufactured according to an embodiment of the present utility model;

FIG. 3 is a schematic illustration of the prior art flow of gum material in a product cavity;

FIG. 4 is a schematic diagram of the overall structure of an embodiment of the present utility model;

FIG. 5 is a schematic view of a solid structure of a fixed mold in an embodiment of the utility model;

FIG. 6 is a schematic top view of a stationary mold in an embodiment of the utility model;

FIG. 7 is a schematic view of the cross-sectional structure A-A of FIG. 6;

FIG. 8 is an enlarged schematic view of portion C of FIG. 7;

FIG. 9 is a schematic view of the first insert and insert of FIG. 7 in combination;

FIG. 10 is a schematic view showing the first insert of FIG. 9 raised and flush with the upper end surface of the mold core;

FIG. 11 is a schematic view of the cross-sectional structure B-B in FIG. 6;

FIG. 12 is a schematic diagram showing a three-dimensional structure of a movable mold according to an embodiment of the present utility model;

FIG. 13 is a schematic diagram of an explosion structure of a movable mold core in an embodiment of the utility model.

Detailed Description

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model belongs; the terminology used in the description is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model; the terms "comprising" and "having" and any variations thereof in the description of the utility model and the claims and the description of the drawings above are intended to cover a non-exclusive inclusion. The terms first, second and the like in the description and in the claims or in the above-described figures, are used for distinguishing between different objects and not necessarily for describing a sequential or chronological order.

Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the utility model. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly appreciate that the described embodiments of the utility model may be combined with other embodiments.

In order to enable those skilled in the art to better understand the present utility model, a technical solution in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings.

As shown in fig. 4-13, an injection mold capable of eliminating flow lines on the surface of a plastic part comprises a movable mold 1 and a fixed mold 2, wherein the movable mold 1 and the fixed mold 2 can be connected in an opening-closing manner, a product cavity 3 is arranged at the joint of the movable mold 1 and the fixed mold 2, and the product cavity 3 is respectively arranged on the lower end face of the movable mold 1 and the upper end face of the fixed mold 2. The fixed die 2 is provided with a die core 4, the movable die 1 is provided with a movable die core 5, the product cavity 3 is arranged on the lower end surface of the movable die core 5, and the die core 4 can extend into the product cavity 3 in the movable die core 5; after the die core 4 stretches into the product cavity 3 of the movable die core 5, a cavity matched with the shape of the product is formed between the inner side wall of the movable die core 5 and the side wall of the die core 4.

During processing, the movable die 1 and the fixed die 2 are respectively arranged on an injection molding machine, and the movable die 1 can be driven to move in a direction approaching to or separating from the fixed die 2 through the injection molding machine, so that the movable die 1 and the fixed die 2 are in sealed connection or separation, and the actions of die closing and die opening are realized; after the injection molding machine drives the mold to be closed, the feeding mechanism injects sizing material into the product cavity 3, and a plastic product conforming to the preset shape is processed after cooling molding.

In this embodiment, the number of product cavities 3 is two, so that after the injection mold is closed and opened once, two plastic parts can be molded at the same time, and the processing efficiency is improved. In other embodiments, the number of product cavities 3 may be any number.

The connecting parts of the mould core 4 and the movable mould core 5 are respectively provided with a runner 6, and the runners 6 are respectively communicated with the two product cavities 3. The upper end face of the movable mould 1 is provided with a material injection port 101, the material injection port 101 is used for being connected with a feeding mechanism of an injection molding machine, and the material injection port 101 is communicated with a runner 6. During processing, the feeding mechanism of the injection molding machine injects liquid sizing material into the movable mold 1 through the material injection port 101, then the liquid sizing material flows into the runner 6, and flows into the two product cavities 3 through the runner 6 for injection molding.

The die core 4 is internally provided with a plurality of inserts, each insert corresponds to the positioning column 200 and the screw column 300 in fig. 2 one by one, the fixed die 2 is provided with an insert driving mechanism, the insert driving mechanism is connected with all the inserts respectively, and the insert driving mechanism can drive the die core 4 of all the inserts to slide, so that the upper end faces of all the inserts can be flush with the upper end face of the die core 4. When the injection mold is processed, before glue is injected, the inserts are driven to move upwards by the insert driving mechanism, so that the upper end faces of all inserts are flush with the upper end face of the mold core 4; at this time, the corresponding slots of the positioning column 200 and the screw column 300 on the product are sealed by the insert; the product cavity 3 is internally provided with a plane, liquid sizing material is injected into the product cavity 3 through the injection molding machine, and the sizing material can not flow through the plane, so that flow marks can not be generated. After the upper end surface of the product is completely filled, driving the insert to move downwards through the insert driving mechanism, so that the insert is respectively retracted into the die core 4 to expose the slots corresponding to the positioning column 200 and the screw column 300, and the sizing material can continuously flow into the slots corresponding to the positioning column 200 and the screw column 300 to fill the positioning column 200 and the screw column 300; and finally, cooling and forming to finish injection molding of a product.

In the processing process of the injection mold, liquid sizing material fills a product cavity 3 in two steps, firstly fills the upper surface of a product, and refills a positioning column 200 and a screw column 300; thereby avoiding the occurrence of the condition that the sizing material forms flow marks due to flow division and flow combination in the product cavity 3 in the process of injecting the sizing material, and improving the yield of injection molding processing.

As shown in fig. 7 to 11, specifically, the insert driving mechanism includes a driving member 7 and an insert mounting plate 8, the driving member 7 is fixedly mounted on the stationary mold 2, and an output end of the driving member 7 is fixedly connected with the insert mounting plate 8. The insert comprises a first insert 9 and a second insert 10, the first insert 9 and the second insert 10 are respectively connected with the insert mounting plate 8, the number of the first inserts 9 is the same as the number of the positioning columns 200 on the plastic product, and the number of the second inserts 10 is the same as the number of the screw columns 300 on the plastic product; in this embodiment, the number of the mold cores 4 is two, and the rib mold cores 4 are in one-to-one correspondence with the product cavity 3, and each mold core 4 is internally provided with 7 first inserts 9 and 4 second inserts 10 respectively. During operation, the driving piece 7 drives the insert mounting plate 8 to move up and down in the fixed die 2, and then drives the first insert 9 and the second insert 10 to move up and down together.

As shown in fig. 2, the heights of the positioning column 200 and the screw column 300 in the product are different, so that the first insert 9 and the second insert 10 can be driven to be flush with the upper end surface of the die core 4 at the same time; therefore, the distance by which the first insert 9 is raised and reset must be smaller than the distance by which the second insert 10 is raised and reset at the time of actual processing.

In this embodiment, the outside of first mold insert 9 has cup jointed stopper 11, and the upper end of mold insert mounting panel 8 is gone up and is equipped with spacing groove 81 respectively with the relevant position of first mold insert 9, spacing groove 81 and stopper 11 adaptation, and first mold insert 9 can slide in spacing groove 81, is provided with limiting plate 12 on the lower terminal surface of mold insert mounting panel 8, limiting plate 12 pass through screw and mold insert mounting panel 8 fixed connection, and first mold insert 9 can pass limiting plate 12, and stopper 11 can respectively with limiting plate 12 and the terminal surface butt of spacing groove 81.

In the initial state, the limiting block 11 is abutted against the end face of the limiting groove 81, and during processing, the driving piece 7 drives the insert mounting plate 8 to move upwards, and the insert mounting plate 8 drives the second insert 10 to synchronously rise, so that the second insert 10 stretches into a slotted hole corresponding to the screw column 300 in the product cavity 3, and is blocked until the upper end face of the second insert 10 is flush with the upper end face of the die core 4; in the process of upward movement of the insert mounting plate 8, the limiting plate 12 is driven to move synchronously, the first insert 9 does not move upward in the initial stage of upward movement, the limiting block 11 slides in the limiting groove 81 until the end face of the limiting block 11 abuts against the limiting plate 12, and then the limiting plate 12 drives the first insert 9 to move upward together with the upward movement of the insert mounting plate 8, so that the first insert 9 stretches into a slotted hole corresponding to the positioning column 200 in the product cavity 3 to be blocked; when the upper end surface of the second insert 10 is flush with the upper end surface of the mold core 4, the upper end surface of the first insert 9 is also just flush with the upper end surface of the mold core 4, so that the product cavity 3 becomes a plane, and then glue stock is injected into the product cavity 3 to mold the upper surface of the product. After the upper surface of the product is filled with sizing materials, the driving piece 7 drives the insert mounting plate 8 to move downwards, and the insert mounting plate 8 drives the second insert 10 to synchronously descend, so that the second insert 10 retracts into the die core 4 to expose slotted holes in the product cavity 3, which correspond to the screw columns 300; at the initial stage of downward movement of the insert mounting plate 8, the first insert 9 does not move, the limiting block 11 slides in the limiting groove 81 until the end face of the limiting block 11 is abutted against the end face of the limiting groove 81, and then the first insert 9 is driven to move downward together with the continued downward movement of the insert mounting plate 8, so that the first insert 9 is retracted into the die core 4, and a slotted hole corresponding to the positioning column 200 in the product cavity 3 is exposed; after the corresponding slot holes of the positioning column 200 and the screw column 300 are exposed, the liquid sizing material can automatically flow into the slot holes to fill the slot holes, so that the sizing material filling of the whole product cavity 3 is completed.

According to the injection mold, through the cooperation of the limiting groove 81, the limiting block 11 and the limiting plate 12, the driving piece 7 drives the insert mounting plate 8 to move, the first insert 9 and the second insert 10 can be driven to move, and the first insert 9 and the second insert 10 can be flush with the upper end face of the mold core 4 at the same time; the plurality of inserts are asynchronously driven to move by a small number of driving pieces 7, so that the number of the driving pieces 7 is reduced, and the manufacturing cost of the die is reduced.

In this example, the driving members 7 are cylinders, the number of the driving members 7 is 4, and the 4 driving members 7 are rectangular and distributed in the fixed mold 2. In other embodiments, each of the first insert 9 and the second insert 10 may be connected to one driving member 7, and the corresponding first insert 9 and second insert 10 may be driven to move by each driving member 7, so that structures such as the insert mounting plate 8, the limiting block 11, the limiting plate 12, and the like are not required.

As shown in fig. 12 and 13, a heating tube 13 is disposed in the movable mold core 5, the heating tube 13 is used for externally connecting a heat source to heat the movable mold core 5, and the heating tube 13 is disposed at the periphery of the product cavity 3 and surrounds the periphery and the upper side of the product cavity 3. During processing, the heating pipes 13 are respectively connected with a heating mechanism of the injection molding machine, and the heating pipes 13 are controlled to generate heat through the injection molding machine, so that the movable mold core 5 is heated, and the function of heating injection molding is realized. The heating pipe 13 can heat the movable mold core 5 to 150-160 ℃, and the molding temperature of the mold is generally only 40-80 ℃ in the traditional injection molding. In this embodiment, the fluidity of the liquid rubber material in the product cavity 3 can be improved by heating the movable mold core 5, so that the possibility of generating flow marks on the surface of the product is further reduced, and the molding yield of the spraying-free plastic part is improved.

The periphery of the movable mold core 5 is sleeved with a heat insulation plate 14, and the heat insulation plate 14 is respectively abutted with the peripheral outer side wall and the upper end face of the movable mold core 5. The heat insulation plate 14 is made of titanium alloy material, and the titanium alloy material has good heat insulation performance, and can reduce outward heat dissipation of the heat in the movable mold core 5, so that heating energy consumption is reduced, and the current environmental protection mainstream trend is met. The heat insulation plate 14 is arranged on the movable mold core 5, so that the heat loss of the movable mold core 5 can be reduced, and the energy consumption for heating the movable mold 1 can be reduced; in addition, only the movable mold core 5 is heated, so that the cooling molding time can be shortened and the injection molding efficiency can be improved.

In order to further reduce the heating energy consumption, in this embodiment, a plurality of hollowed-out grooves 51 are provided on the outer side wall of the movable mold core 5, the hollowed-out grooves 51 are respectively distributed on the peripheral side wall of the movable mold core 5 and on the end surface of the movable mold core 5 on one side far away from the fixed mold 2, the heat insulation plate 14 is respectively provided with a bump 15 at a position corresponding to the hollowed-out groove 51, and the shape of the bump 15 is adapted to the shape of the corresponding hollowed-out groove 51; after the heat insulation plate 14 is mounted on the movable mold core 5, the protruding blocks 15 are respectively clamped and limited with the corresponding hollow grooves 51. By providing the plurality of hollow grooves 51 on the movable mold core 5, the volume of the movable mold core 5 can be reduced; the volume of the movable mould core 5 is reduced, and the energy consumption for heating the movable mould core 5 to a preset temperature can be naturally reduced, so that the overall energy consumption of the injection mould is reduced.

Cooling water pipes 16 are respectively arranged in the movable die 1 and the fixed die 2, the cooling water pipes 16 are respectively distributed on the periphery of the die core 4 and the periphery of the movable die core 5, water inlet connectors 21 and water outlet connectors 22 are respectively arranged on the outer side walls of the movable die 1 and the fixed die 2, and the water inlet connectors 21 and the water outlet connectors 22 are respectively communicated with the corresponding cooling water pipes 16. During operation, the water inlet joint 21 and the water outlet joint 22 are respectively connected with a cooling system of the injection molding machine, cooling water can flow into the cooling water pipe 16 from the water inlet joint 21 through the cooling system of the injection molding machine, then flows into the water outlet joint 22 through the cooling water pipe 16, and then flows back into the cooling system of the injection molding machine to realize waterway circulation of the cooling water. After the product in the product cavity 3 is molded, the injection molding machine controls the cooling system to work, the cooling water pipe 16 is respectively contacted with the movable mold core 5 and the mold core 4, and cooling water in the cooling water pipe 16 can be in heat exchange with the movable mold core 5 and the mold core 4, so that heat of the movable mold core 5 and the mold core 4 is taken away, the movable mold core 5 and the mold core 4 are cooled, and the product in the product cavity 3 can be rapidly cooled and molded.

Four positioning grooves 102 are formed in the lower end face of the movable die 1, two positioning grooves 102 are transversely distributed, the other two positioning grooves are vertically distributed, positioning blocks 23 are respectively arranged at positions, corresponding to the positioning grooves 102, on the fixed die 2, and the positioning blocks 23 are detachably clamped with the positioning grooves 102. In the process of die assembly, the positioning blocks 23 can be respectively clamped into the corresponding positioning grooves 102, the sealing connection between the movable die 1 and the fixed die 2 can be ensured through the matching of the positioning grooves 102 and the positioning blocks 23, the accuracy of die assembly transmission is improved, and dislocation of the movable die 1 and the fixed die 2 during processing can be prevented.

The foregoing embodiments are preferred embodiments of the present utility model, and are not intended to limit the scope of the utility model, which is defined by the appended claims, but rather by the following claims.

Claims (10)

1. An injection mold capable of eliminating flow marks on the surface of a plastic part, which is characterized in that: including movable mould and cover half, movable mould and cover half can open and shut and be connected, the junction of cover half and movable mould is provided with the product die cavity, be equipped with the mould benevolence in the cover half, the mould benevolence can stretch into in the product die cavity, be equipped with a plurality of inserts in the mould benevolence, be equipped with mold insert actuating mechanism on the cover half, mold insert actuating mechanism is connected with all inserts respectively, mold insert actuating mechanism can drive the mold insert slides in the mould benevolence, and then makes the up end of all inserts can with the up end of mould benevolence flushes.

2. The injection mold capable of eliminating flow marks on the surface of a plastic part according to claim 1, wherein: the insert driving mechanism comprises a driving piece and an insert mounting plate, wherein the driving piece is connected with the fixed die, the output end of the driving piece is connected with the insert mounting plate, and the inserts are respectively connected with the insert mounting plate.

3. The injection mold capable of eliminating flow marks on the surface of a plastic part according to claim 2, wherein: the mold inserts include first mold insert and second mold insert, first mold insert and second mold insert respectively with the mold insert mounting panel is connected, the quantity of first mold insert is the same with the reference column quantity on the plastic part product, the quantity of second mold insert is the same with the screw post quantity on the plastic part product.

4. The injection mold capable of eliminating flow marks on the surface of a plastic part according to claim 3, wherein: the limiting block is sleeved on the first insert, a limiting groove is formed in the lower end face of the insert mounting plate and corresponding to the first insert, the first insert can slide in the limiting groove, a limiting plate is arranged on the lower end face of the insert mounting plate, the first insert can penetrate through the limiting plate, and the limiting block can be respectively abutted to the limiting plate and the end face of the limiting groove.

5. The injection mold capable of eliminating flow marks on the surface of a plastic part according to any one of claims 1 to 4, wherein: the movable mold is provided with a movable mold core, the product cavity is arranged on the lower end face of the movable mold core, heating pipes are arranged in the movable mold core, and the heating pipes are distributed on the periphery of the product cavity.

6. The injection mold capable of eliminating flow marks on the surface of a plastic part according to claim 5, wherein: the periphery of the movable mold core is sleeved with a heat insulation plate, and the heat insulation plate is respectively in mutual butt joint with the peripheral outer side wall and the upper end face of the movable mold core.

7. The injection mold capable of eliminating flow marks on the surface of a plastic part according to claim 6, wherein: the heat insulation plate is characterized in that hollow grooves are formed in the outer side wall and the upper end face of the movable mold core respectively, protruding blocks are arranged at positions corresponding to the hollow grooves on the heat insulation plate respectively, the protruding blocks are matched with the corresponding hollow grooves, and the protruding blocks are inserted into the corresponding hollow grooves to be in limiting connection.

8. The injection mold capable of eliminating flow marks on the surface of a plastic part according to claim 5, wherein: cooling water pipes are respectively arranged in the movable die and the fixed die, the cooling water pipes are respectively distributed on the periphery of the die core and the movable die core, water inlet connectors and water outlet connectors are respectively arranged on the outer side walls of the movable die and the fixed die, and the water inlet connectors and the water outlet connectors are respectively communicated with the corresponding cooling water pipes.

9. The injection mold capable of eliminating flow marks on the surface of a plastic part according to any one of claims 1 to 4 or 6 to 8, wherein: the number of the product cavities is two, a runner is arranged at the joint of the fixed die and the movable die, and the runner is respectively communicated with the two product cavities.

10. The injection mold capable of eliminating flow marks on the surface of a plastic part according to claim 9, wherein: the lower end face of the movable die is provided with a plurality of positioning grooves, positioning blocks are respectively arranged at positions corresponding to the positioning grooves on the fixed die, and the positioning blocks are detachably clamped with the corresponding positioning grooves.