CN115782091A

CN115782091A - Injection mold device and demolding method for plastic parts

Info

Publication number: CN115782091A
Application number: CN202211540928.XA
Authority: CN
Inventors: 肖玉仁; 肖兴远; 王平
Original assignee: Ji'an Chuangfu Precision Manufacturing Co ltd
Current assignee: Ji'an Chuangfu Precision Manufacturing Co ltd
Priority date: 2022-12-02
Filing date: 2022-12-02
Publication date: 2023-03-14

Abstract

The invention discloses an injection mold device for a plastic part, which comprises a fixed plate and a movable plate, wherein a fixed mold is fixedly arranged on the surface of one side of the fixed plate. Has the advantages that: when the novel plastic injection molding machine is used for demolding, the movable mold is opened and the plastic part is demolded synchronously, demolding action is fast, demolding efficiency is higher, demolding is performed through air flow, the trouble of installing ejector pins of the mold is eliminated, the structure of the mold is greatly simplified, consumption of easily damaged parts is reduced, maintenance and manufacturing cost is reduced, meanwhile, the phenomenon of blocking is reduced, the situations of bubbles and incomplete injection molding are avoided, and injection molding efficiency is improved.

Description

Injection mold device and demolding method for plastic part

Technical Field

The invention relates to the technical field of plastic part injection molds, in particular to an injection mold device and a demolding method for a plastic part.

Background

The injection mold is a tool for producing plastic products and also a tool for endowing the plastic products with complete structures and accurate dimensions, and the injection molding is a processing method used for batch production of parts with complex shapes, in particular to a method for injecting heated and melted plastics into a mold cavity from an injection molding machine at high pressure and obtaining a formed product after cooling and solidification.

The traditional injection mold is provided with a thimble for demolding, also called mold thimble, for example, with publication number CN107399050A, named as an injection mold of plastic material, and with publication number CN110142931A, named as an injection molding mold of plastic ornament for automobiles, both of the above applications adopt the thimble as a demolding structure, because the thimble needs to penetrate through the mold cavity, its size needs to be strictly controlled, the manufacturing cost is higher, and with the increase of the use duration, the friction effect will affect the wear degree of the thimble, leading to the need to replace the thimble regularly, the maintenance and production costs will also increase, and the complexity of the structure of the mold itself is also increased, meanwhile, during the injection molding, the interior of the mold cavity is in a closed state, in order to discharge the air in the mold cavity, the injection molding method is characterized in that an exhaust port needs to be formed, air in a mold cavity is gradually extruded in the process of injecting injection molding materials into the mold cavity, the injection molding process is completed, however, in the actual production process, the problem that the mold cavity cannot be filled with the injection molding materials due to the blockage of the exhaust port, the blockage of an injection molding port and the residual air in the mold cavity can cause defective products, and the injection molding stability is affected.

An effective solution to the problems in the related art has not been proposed yet.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides the injection mold device and the demolding method for the plastic part, which have the advantages of pneumatic demolding, simplified structure, reduced manufacturing cost, improved injection molding efficiency and improved use convenience, and further solve the problems in the background art.

(II) technical scheme

In order to realize the advantages of pneumatic demoulding, structure simplification, cost reduction, injection molding efficiency improvement and use convenience improvement, the invention adopts the following specific technical scheme:

the utility model provides an injection mold device of plastic part, includes fixed plate and movable plate, fixed plate one side fixed surface installs the cover half, and the cover half opposite side has seted up the die cavity, the corresponding cover half fixed mounting in movable plate side surface has the movable mould, the inside first gas transmission passageway of having seted up of cover half, and first gas transmission passageway one end and die cavity through connection to first gas transmission passageway other end through connection has the third shunt pipe, the fixed plate surface is located the cover half both sides and runs through the fixedly connected with urceolus, and the urceolus other end pegs graft and has interior pole, and the interior pole other end and movable plate fixed connection, interior pole one end is located the inside fixed mounting of urceolus has the piston, and piston and urceolus interference fit, the urceolus other end through connection has first shunt pipe, and first gas transmission pipe through first gas-supply pipe through connection has first pump of aerifing to first shunt pipe and third shunt pipe other end through connection, the inside first gas transmission passageway of perpendicular to of cover half has seted up the interference groove, and the inside cooperation of urceolus has the closure plate to the closed groove other end fixed mounting has a spacing post, the inside second gas transmission passageway of having seted up of cover half, and the second gas transmission passageway one end through connection has the second shunt pipe through the other end through connection of moulding plastics the injection molding machine, and the injection molding through the other end through the injection molding output end through the second shunt pipe, and the injection molding machine.

Furthermore, a guide rod is fixedly arranged at a corner of the surface of the fixed plate, penetrates through the movable plate and is connected with the movable plate in a sliding manner.

Furthermore, the other end of the guide rod is fixedly sleeved with a baffle plate outside the movable plate, and the guide rod is positioned outside the fixed die and the movable die.

Furthermore, the fixed die is internally positioned outside the die cavity and is penetrated by a water cooling groove, and two ends of the water cooling groove are connected with water cooling pipes in a through mode.

Furthermore, a screw rod is welded at one end of the inner rod and penetrates through the central axis of the piston, an end plate is sleeved at one end of the piston and located on the outer side of the screw rod, and a nut is sleeved at the other end of the screw rod in a threaded manner and abuts against the end plate.

Furthermore, the blocking plate is made of high-temperature-resistant rubber, and the area of the blocking plate is larger than the inner diameter of the first gas transmission channel.

Furthermore, the guide rod is a smooth round rod and is made of metal.

Furthermore, the first shunt pipe and the second shunt pipe are arranged in a staggered mode with the injection molding opening.

Furthermore, the cooperation of the first air pump and the second air pump is used to have a controller, and the output end of the controller is electrically connected with the input ends of the first air pump and the second air pump.

A demoulding method of an injection mould device of a plastic part comprises the following steps:

s1, mold closing process: the first air inflation air suction pump is used for sucking air, and the second air inflation air suction pump is used for sucking air;

s2, injection molding: the second air inflation and air suction pump inflates air, and the first air inflation and air suction pump keeps an air suction state;

s3, demolding: the first air inflation and air suction pump inflates air, and the second air inflation and air suction pump sucks air.

(III) advantageous effects

Compared with the prior art, the invention provides an injection mold device and a demolding method for a plastic part, which have the following beneficial effects:

(1) The invention adopts a first inflation air pump, a first shunt pipe, a second inflation air pump and a second shunt pipe, when demoulding, the second inflation air pump pumps air, the air in the second air transmission channel is pumped out through the second shunt pipe, the blocking plate returns to the inside of the closed groove to be abutted against the limiting column through the air pressure action, so that the first air transmission channel is opened, the first inflation air pump inflates air, high-pressure air flow is generated to be injected into the first shunt pipe, after the air flow passes through the shunt pipe, a part of air enters the outer barrel, the other part of air enters the first air transmission channel along the third shunt pipe, the air entering the first air transmission channel pushes the piston to move through the air pressure, the movable mould is opened, the air entering the first air transmission channel blows off the formed plastic part through the air pressure, the adhesion of the plastic part and the mould cavity is avoided, so that the demoulding is finished.

(2) When the invention is used for die assembly, the first air-inflation air pump is used for pumping air, the piston pulls the inner rod to move to drive the movable die to be close to and matched with the fixed die, meanwhile, the first air transmission channel is in an open state at the moment, air positioned in the die cavity enters the third shunt pipe through the first air transmission channel and enters the first air-inflation air pump through the first shunt pipe to be discharged, so that a vacuum negative pressure state is formed in the die cavity, then, the second air-inflation air pump is used for inflating, the blocking plate is pushed by air pressure to move to block the first air transmission channel, meanwhile, the blocking plate is close to the die cavity, the size of a water gap formed by a plastic part is smaller, the material waste phenomenon is less, the structure is simpler compared with that of a valve structure, the problem of valve blocking is avoided, when in injection molding, the injection molding material directly sprays into the mold cavity through the injection molding opening, and air does not exist in the mold cavity at the moment, so that the problem of exhaust is solved, meanwhile, negative pressure is formed in the mold cavity, pressure difference is generated between the negative pressure and injection molding equipment, the injection molding material is discharged more smoothly, the blocking phenomenon is reduced, meanwhile, bubbles and the situation of incomplete injection molding are avoided, and the injection molding efficiency is improved.

(3) The guide rod is positioned on the outer sides of the fixed die and the movable die, the inner rod and the outer cylinder are positioned on two sides of the fixed die and the movable die, and a worker can arrange the conveyor below the fixed die and the movable die.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a schematic view of an external structure of an injection mold device for plastic parts according to an embodiment of the present invention;

FIG. 2 is a schematic diagram illustrating an internal structure of an injection mold apparatus for plastic parts according to an embodiment of the present invention;

FIG. 3 is a top view of an apparatus for injection molding plastic parts according to an embodiment of the present invention;

FIG. 4 is a side view of an apparatus for injection molding a plastic part according to an embodiment of the present invention;

FIG. 5 is an enlarged view of a node A of an apparatus for injection molding a plastic part according to an embodiment of the present invention;

FIG. 6 is an enlarged view of a node B of an apparatus for injection molding a plastic part according to an embodiment of the present invention;

FIG. 7 is a schematic illustration of an installation of a piston according to an embodiment of the invention;

FIG. 8 is a schematic diagram of a guide bar according to an embodiment of the present invention;

fig. 9 is a flowchart illustrating a method for demolding an injection mold device for plastic parts according to an embodiment of the present invention.

In the figure:

1. a fixing plate; 2. fixing a mold; 3. a mold cavity; 4. a movable plate; 5. moving the mold; 6. an injection molding port; 7. a first air pump; 8. a second air pump; 9. a first gas delivery pipe; 10. a second gas delivery pipe; 11. a first shunt pipe; 12. a second shunt pipe; 13. a third shunt pipe; 14. a first gas transmission channel; 15. a second gas transmission channel; 16. a water cooling tank; 17. an outer cylinder; 18. a piston; 19. a guide bar; 20. an inner rod; 21. a baffle plate; 22. a water-cooled tube; 23. closing the tank; 24. blocking plates; 25. a limiting column; 26. an end plate; 27. a screw; 28. and (4) a nut.

Detailed Description

For further explanation of the various embodiments, the drawings which form a part of the disclosure and which are incorporated in and constitute a part of this specification, illustrate embodiments and, together with the description, serve to explain the principles of operation of the embodiments, and to enable one skilled in the art to understand the embodiments and advantages of the disclosure for reference and without scale, wherein elements are not shown in the drawings and like reference numerals are used to refer to like elements generally.

According to an embodiment of the invention, an injection mold device and a demolding method for a plastic part are provided.

Referring to the drawings and the detailed description, the invention is further described, as shown in fig. 1-9, an injection mold device for plastic parts according to an embodiment of the invention includes a fixed plate 1 and a movable plate 4, the fixed plate 1 is fixedly installed, a fixed mold 2 is fixedly installed on one side surface of the fixed plate 1, a mold cavity 3 is opened on the other side of the fixed mold 2, a movable mold 5 is fixedly installed on one side surface of the movable plate 4 corresponding to the fixed mold 2, a first gas transmission channel 14 is opened inside the fixed mold 2, one end of the first gas transmission channel 14 is connected with the mold cavity 3 in a penetrating manner, the other end of the first gas transmission channel 14 is connected with a third shunt 13 in a penetrating manner, an outer cylinder 17 is fixedly connected on two sides of the fixed mold 1, the other end of the outer cylinder 17 is connected with an inner rod 20 in a inserting manner, the other end of the inner rod 20 is fixedly connected with the movable plate 4, one end of the inner rod 20 is fixedly installed inside the outer cylinder 17, a piston 18 is in an interference fit manner, the outer cylinder 17 is of a common structure, the other end of the outer cylinder 17 is connected with the first shunt 11, the first shunt 11 is connected with a first gas transmission channel 9, a first gas pump 7 is connected with a sealing groove 23, the other end of the second gas transmission channel 23, the second shunt is connected with a sealing groove 23, the second gas transmission channel 14, the second gas transmission channel 23 is connected with a sealing groove 15, the second gas transmission channel 14, the second shunt pipe 12 is connected with a second inflation air pump 8 through a second air pipe 10, the fixed mold 2 is internally provided with an injection molding opening 6 in a penetrating way, one end of the injection molding opening 6 is connected with the mold cavity 3 in a penetrating way, the other end of the injection molding opening 6 is communicated with the output end of the injection molding machine, the common injection molding structure is a common injection molding structure, and the common injection molding structure is not described herein, when demolding is carried out, the second inflation air pump 8 pumps air, air in the second air transmission channel 15 is pumped out through the second shunt pipe 12, the blocking plate 24 is returned to the inside of the closed groove 23 to be abutted against the limiting column 25 through the air pressure action, so that the first air transmission channel 14 is opened, the first inflation air pump 7 inflates to generate high-pressure air flow to be injected into the first shunt pipe 11, after the high-pressure air flow is shunted through the third shunt pipe 13, one part of the air enters the outer barrel 17, the other part of the air enters the first air transmission channel 14 along the third shunt pipe 13, the gas entering the outer cylinder 17 pushes the piston 18 to move through the air pressure, the movable mold 5 is opened, the gas entering the first gas transmission channel 14 blows off the formed plastic part through the air pressure, the adhesion of the plastic part and the mold cavity 3 is avoided, and the demolding is finished, when the device is demolded, the opening of the movable mold 5 and the demolding of the plastic part are finished synchronously, the demolding action is fast, the demolding efficiency is higher, and the demolding is carried out through the air flow, the trouble of installing a mold thimble is omitted, the structure of the mold is greatly simplified, the consumption of a vulnerable part is reduced, the maintenance and manufacturing cost is reduced, meanwhile, when the mold is closed, the first inflation air suction pump 7 carries out air suction, the piston 18 pulls the inner rod 20 to move to drive the movable mold 5 to be close to and to be closed with the fixed mold 2, meanwhile, the first gas transmission channel 14 is in the opening state at the moment, the air inside the mold cavity 3 enters the third shunt pipe 13 through the first gas transmission channel 14, the injection molding material enters the first air pump 7 through the first flow dividing pipe 11 to be discharged, so that a vacuum negative pressure state is formed inside the mold cavity 3, then the second air pump 8 inflates, the blocking plate 24 is pushed by air pressure to move to block the first air transmission channel 14, meanwhile, the blocking plate 24 is close to the mold cavity 3, the size of a water gap formed by a plastic part is smaller, the material waste phenomenon is less, the structure is simpler compared with a valve structure, and the problem of valve blockage is avoided.

In one embodiment, a guide rod 19 is fixedly installed at a corner of the surface of the fixed plate 1, the guide rod 19 penetrates through the movable plate 4 and is in sliding connection with the movable plate 4, the guide rod 19 is used for guiding the movement of the movable plate 4, a baffle plate 21 is fixedly sleeved at the other end of the guide rod 19 and is positioned outside the movable plate 4, the movable plate 4 is prevented from being separated from the guide rod 19 and is limited by the movable plate 4, the guide rod 19 is positioned outside the fixed die 2 and the movable die 5, the inner rod 20 and the outer cylinder 17 are positioned on two sides of the fixed die 2 and the movable die 5, a worker can arrange a conveyor below the fixed die 2 and the movable die 5, after demolding is completed, a molded plastic part directly falls onto the conveyor, and can be conveyed to the next process, the trouble of manual carrying is eliminated, and the use convenience is further improved.

In one embodiment, the water cooling groove 16 is formed in the fixed mold 2 outside the mold cavity 3, and the two ends of the water cooling groove 16 are connected with the water cooling pipes 22 through a through manner, and the water cooling pipes 22 are of a common water cooling structure, and cold water can be introduced into the water cooling groove 16 and enter the water cooling groove 16 to cool the plastic part and accelerate the molding process.

In one embodiment, a screw 27 is welded at one end of the inner rod 20, the screw 27 penetrates through a central axis of the piston 18, an end plate 26 is sleeved at one end of the piston 18 outside the screw 27, a nut 28 is sleeved at the other end of the screw 27 in a threaded manner, the nut 28 abuts against the end plate 26, and the end plate 26 seals a gap between the screw 27 and the piston 18, so that air tightness is improved.

In one embodiment, the blocking plate 24 is made of high temperature resistant rubber material, so as to prevent the high temperature of the injection molding material from affecting the shape of the blocking plate 24, and the area of the blocking plate 24 is larger than the inner diameter of the first gas transmission channel 14, so as to facilitate blocking the first gas transmission channel 14.

In one embodiment, the guide rod 19 is a smooth round rod, and the guide rod 19 is made of metal, which is a common guide structure.

In one embodiment, the first shunt tube 11 and the second shunt tube 12 are offset from the injection port 6 to facilitate connection of the injection port 6 to an injection molding apparatus.

In an embodiment, the first air pump 7 and the second air pump 8 are used in cooperation with a controller, and an output end of the controller is electrically connected to input ends of the first air pump 7 and the second air pump 8, which is a common control form and will not be described herein.

s1, mold closing process: the first air-inflation air-suction pump 7 is used for pumping air to drive the piston 18 to move and drive the movable mould 5 to move close to the top mould, and simultaneously air in the mould cavity 3 is pumped out, and the second air-inflation air-suction pump 8 is used for pumping air to keep the first air transmission channel 14 open;

s2, injection molding: the second air-inflation air pump 8 inflates air to enable the blocking plate 24 to seal the first air transmission channel 14, so that injection molding materials are prevented from entering the first air transmission channel 14, the first air-inflation air pump 7 keeps an air-pumping state, and air tightness is improved;

s3, demolding: the first air pump 7 is inflated, the movable mould 5 is moved to be opened, meanwhile, the formed plastic part is blown off, the second air pump 8 is inflated to open the first air flow channel, and the plastic part is blown off through the air flow conveniently.

The working principle is as follows:

when the die is closed, the first air-inflation air-extraction pump 7 extracts air, the piston 18 pulls the inner rod 20 to move, the movable die 5 is driven to be close to and to be closed with the fixed die 2, meanwhile, the first air-transmission channel 14 is in an open state at the moment, air in the die cavity 3 enters the third shunt pipe 13 through the first air-transmission channel 14 and enters the first air-inflation air-extraction pump 7 through the first shunt pipe 11 to be discharged, so that the inside of the die cavity 3 forms a vacuum negative pressure state, then, the second air-inflation air-extraction pump 8 inflates, the blocking plate 24 is pushed by air pressure to move to block the first air-transmission channel 14, when in injection molding, the injection molding material is directly injected into the die cavity 3 through the injection molding opening 6, because no air exists in the die cavity 3 at the moment, the problem of exhaust is saved, meanwhile, because the inside of the die cavity 3 presents negative pressure, pressure difference is generated between the injection molding equipment, the injection molding material is discharged more smoothly, and the blocking phenomenon is reduced, meanwhile, the occurrence of the situation of air bubbles and incomplete injection molding is avoided, the injection molding efficiency is improved, the movable mold 5 is synchronously fixed during the air exhaust, the movable mold 5 and the fixed mold 2 are more tightly connected with each other along with the continuous extraction of the air in the mold cavity 3 and the outer cylinder 17, the occurrence of leakage is avoided, the sealing performance is better, meanwhile, the use of an air cylinder or a hydraulic rod is omitted, the structure is further simplified, the manufacturing cost is further reduced, during the demolding, the second air inflation and air extraction pump 8 performs the air extraction, the air in the second air delivery channel 15 is extracted through the second flow dividing pipe 12, the blocking plate 24 returns to the inside of the closed groove 23 to be abutted against the limiting column 25 through the air pressure action, the first air delivery channel 14 is further opened, the first air inflation and air extraction pump 7 performs the air inflation, and the generated high-pressure air flow is injected into the first flow dividing pipe 11, after the shunting of the third shunt pipe 13, a part of gas enters the outer cylinder 17, the other part of gas enters the first gas transmission channel 14 along the third shunt pipe 13, the gas entering the outer cylinder 17 pushes the piston 18 to move through the air pressure, the movable mold 5 is opened, the gas entering the first gas transmission channel 14 blows off the formed plastic part through the air pressure, the adhesion of the plastic part and the mold cavity 3 is avoided, and the demolding is completed.

In the present invention, unless otherwise explicitly stated or limited, the terms "mounted," "disposed," "connected," "fixed," "screwed" and the like are to be understood broadly, for example, as being fixedly connected, detachably connected, or integrated; can be mechanically or electrically connected; the terms may be directly connected or indirectly connected through an intermediate, and may be communication between two elements or interaction relationship between two elements, unless otherwise specifically limited, and the specific meaning of the terms in the present invention will be understood by those skilled in the art according to specific situations.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. The utility model provides an injection mold device of plastic part, its characterized in that, includes fixed plate (1) and movable plate (4), fixed plate (1) one side surface fixed mounting has cover half (2), and cover half (2) opposite side has seted up die cavity (3), movable plate (4) one side surface corresponds cover half (2) fixed mounting has movable mould (5), cover half (2) inside has seted up first gas transmission passageway (14), and first gas transmission passageway (14) one end and die cavity (3) through connection to first gas transmission passageway (14) other end through connection has third shunt (13), fixed plate (1) surface is located cover half (2) both sides and runs through fixedly connected with urceolus (17), and urceolus (17) other end pegs graft and has interior pole (20) to interior pole (20) other end and movable plate (4) fixed connection, interior pole (20) one end is located urceolus (17) inside fixed mounting has piston (18), and piston (18) and urceolus (17) interference fit, the urceolus (17) other end is connected with first shunt (11), and first shunt (11) link up first shunt (9) through connection has first shunt (7) and first shunt (13), closed slot (23) have been seted up to the first gas transmission passageway of the inside perpendicular to of cover half (2) (14), and closed slot (23) inside interference fit has closure plate (24) to closed slot (23) other end fixed mounting has spacing post (25), second gas transmission passageway (15) have been seted up to cover half (2) inside, and second gas transmission passageway (15) one end and closed slot (23) other end through connection to second gas transmission passageway (15) other end through connection has second shunt tubes (12), second shunt tubes (12) have second through connection through second gas-supply pipe (10) through connection and aerify aspiration pump (8), cover half (2) inside runs through and has seted up mouth of moulding plastics (6), and mouth of moulding plastics (6) one end and die cavity (3) through connection to the mouth of moulding plastics (6) other end switch-on injection molding machine output.

2. The apparatus as claimed in claim 1, wherein guide rods (19) are fixedly installed at corners of the surface of the stationary plate (1), and the guide rods (19) penetrate through the movable plate (4) and are slidably connected to the movable plate (4).

3. The injection mold device for plastic parts as claimed in claim 2, wherein the other end of the guide rod (19) is fixedly connected with a baffle (21) outside the movable plate (4), and the guide rod (19) is located outside the fixed mold (2) and the movable mold (5).

4. The injection mold device for the plastic part as claimed in claim 1, wherein a water cooling groove (16) is formed through the fixed mold (2) at the outer side of the mold cavity (3), and water cooling pipes (22) are connected to both ends of the water cooling groove (16).

5. The injection mold device for plastic parts, according to claim 1, characterized in that one end of the inner rod (20) is welded with a screw (27), the screw (27) penetrates through a central axis of the piston (18), one end of the piston (18) is located outside the screw (27) and sleeved with an end plate (26), the other end of the screw (27) is sleeved with a nut (28) in a threaded manner, and the nut (28) abuts against the end plate (26).

6. The injection mold device for plastic parts according to claim 1, wherein the blocking plate (24) is made of high temperature resistant rubber, and the area of the blocking plate (24) is larger than the inner diameter of the first gas transmission channel (14).

7. The injection mold device for plastic parts, according to claim 2, wherein the guide rod (19) is a smooth round rod, and the guide rod (19) is made of metal.

8. The injection molding apparatus for plastic parts according to claim 1, wherein the first and second shunt pipes (11, 12) are arranged offset from the injection port (6).

9. The injection mold device for plastic parts, according to claim 1, wherein the first air pump (7) and the second air pump (8) are used in combination with a controller, and the output end of the controller is electrically connected to the input ends of the first air pump (7) and the second air pump (8).

10. A method for removing a mold from an injection mold apparatus for plastic parts, comprising the injection mold apparatus for plastic parts according to any one of claims 1 to 9, the method comprising:

s1, mold closing process: the first air-inflation air pump (7) pumps air, and the second air-inflation air pump (8) pumps air;

s2, injection molding: the second air inflation air suction pump (8) inflates air, and the first air inflation air suction pump (7) keeps an air suction state;

s3, demolding: the first inflation air pump (7) inflates air, and the second inflation air pump (8) pumps air.