Split type bottom die structure, bottle blowing die and blowing method

Abstract

The invention discloses a split type bottom die structure, a bottle blowing die and a blowing method, and belongs to the technical field of bottle blowing dies. The split type bottom die structure comprises a bottom die body, a plurality of bottom die inserts and a driving assembly; the bottom die body is provided with a bottle bottom center forming face and a plurality of bottle bottom claw forming faces which are sequentially arranged on the periphery of the bottle bottom center forming face, and a bottom die body recess is formed between every two adjacent bottle bottom claw forming faces of the bottom die body. A plurality of bottom die inserts are arranged in a bottom die body and can synchronously move in the longitudinal direction under the action of a driving assembly, so that the bottom die inserts can be switched between a forming position and a non-forming position; therefore, the material at the bottom of the bottle blank keeps consistent ductility during blow molding and can flow relatively consistently under the action of stretching to form a bottle bottom structure with uniform wall thickness, so that each position of the bottle bottom structure has enough strength, the molding quality of the bottle bottom is ensured, the gram weight of the material can be reduced, and the light weight of the plastic bottle is facilitated.

Description

Technical Field

[0001] This invention belongs to the field of blow molding technology, specifically relating to a split bottom mold structure, blow molding mold and blow molding method. Background Technology

[0002] Plastic bottled beverages have gained widespread acceptance, and some plastic bottles have been designed with claw-like structures at the bottom to improve performance. For example, the five-claw-like bottle bottom structure disclosed in patent announcement number CN216233459U includes a central bottom and alternating claw-like segments and grooves around the center. This five-claw-like bottom structure enhances the pressure resistance and deformation resistance of the plastic bottle bottom.

[0003] Plastic bottles are blow molded in a blow molding die. The bottom of the plastic bottle is formed in the bottom mold of the blow molding die. The inner forming surface of the bottom mold includes a central forming surface and claw forming surfaces and groove forming surfaces that are alternately distributed around the central forming surface. The central forming surface is used to form the center of the bottle bottom, the claw forming surfaces are used to form the claws of the bottle bottom, and the groove forming surfaces are used to form the grooves of the bottle bottom.

[0004] During the blow molding process of plastic bottles, because the groove forming surface bulges upwards, the material at the bottom of the preform will contact the groove forming surface first. The temperature of the groove forming surface is much lower than the temperature of the material at the bottom of the preform at this time. As a result, the part of the material in contact with the groove forming surface cools down prematurely, thereby reducing the ductility of that part of the material. This has the following drawbacks: 1. Inconsistent stretching of the bottom material of the preform can easily lead to uneven distribution of plastic thickness in the bottom structure, affecting the quality of the plastic bottle.

[0005] 2. To fully stretch the material at the bottom of the preform, higher blowing pressure is required, increasing energy consumption and violating the green concept of energy conservation.

[0006] 3. In order to ensure the strength of the bottle bottom, more raw materials are needed for the bottle bottom, which is not conducive to the lightweighting of plastic bottles and violates the green concept of reducing materials. Summary of the Invention

[0007] In order to overcome at least some of the shortcomings of the prior art, the present invention provides a split bottom mold structure, a blow molding die, and a blow molding method.

[0008] The technical solution of the split bottom mold structure provided by the present invention is as follows: A split-type bottom mold structure, characterized in that it includes a bottom mold body, multiple bottom mold inserts, and a driving assembly; The bottom mold body has a central forming surface for the bottom of the bottle and a plurality of bottle bottom claw forming surfaces arranged sequentially around the central forming surface for the bottom of the bottle. The bottom mold body has a bottom mold body recess between two adjacent bottle bottom claw forming surfaces. Each of the plurality of bottom mold inserts has a bottle bottom groove forming surface. The driving component is connected to the plurality of bottom mold inserts and drives the plurality of bottom mold inserts to move within the recesses of the plurality of bottom mold bodies. The plurality of bottom mold inserts can be moved to a forming position where the plurality of bottle bottom groove forming surfaces, the plurality of bottle bottom claw forming surfaces, and the bottle bottom center forming surface together form a bottle bottom forming surface. They can also be moved to a non-forming position where the plurality of bottle bottom groove forming surfaces are offset downward relative to the plurality of bottle bottom claw forming surfaces and the bottle bottom center forming surface. The bottom mold body has a bottom mold body cooling channel, and the multiple bottom mold inserts each have a bottom mold insert cooling channel. The bottom mold body cooling channel can remain connected with the multiple bottom mold insert cooling channels when the multiple bottom mold inserts move.

[0009] As a further technical solution of the present invention, the driving component includes a driving device and a synchronous moving mechanism. The driving device is connected to a plurality of bottom mold inserts through the synchronous moving mechanism, thereby driving the plurality of bottom mold inserts to move synchronously.

[0010] As a further technical solution of the present invention, the synchronous movement mechanism includes multiple connecting rods and a connecting plate; The upper ends of the multiple connecting rods are respectively connected to the multiple bottom mold inserts; The connecting plate is located below the bottom mold body; The lower ends of the multiple connecting rods are respectively connected to the connecting plate; The driving device is installed on the outer wall of the bottom mold body, and the driving end of the driving device is connected to the connecting plate.

[0011] As a further technical solution of the present invention, the cooling water channel of the bottom mold body and the cooling water channels of the plurality of bottom mold inserts are connected by a flexible connecting component, and the flexible connecting component is configured to adapt to the positional changes of the bottom mold inserts relative to the bottom mold body.

[0012] As a further technical solution of the present invention, the cooling water channel of the bottom mold body includes: The first water inlet extends from the bottom wall of the bottom mold body toward the center forming surface of the bottle bottom; The first water outlet extends inward from the bottom wall of the bottom mold body; Multiple first branch water channels, one end of which is connected to the first inlet water channel, the middle part of which extends along the trend of the multiple bottle bottom claw-shaped surfaces, and the other end of which is connected to the first outlet water channel. Multiple second branch waterways are distributed alternately with multiple first branch waterways along the circumference, with one end connected to the first water inlet channel and the other end extending to connect with multiple recesses of the bottom mold body. The cooling water channels of the bottom mold insert include: The third branch water channel extends at one end to the outer wall of the bottom mold insert and remains connected to the corresponding second branch water channel. The middle part extends along the trend of the bottom groove forming surface, and the other end extends to the outer wall of the bottom mold insert and remains connected to the first outlet water channel.

[0013] As a further technical solution of the present invention, the cooling water channel of the bottom mold body also includes: A water outlet channel surrounds the bottom mold body circumferentially. Multiple water outlet channels are connected, with one end extending to connect with multiple recesses of the bottom mold body, and the other end connecting to the water outlet central channel. The other ends of the multiple first branch waterways are respectively connected to the water outlet central waterway, the other end of the third branch waterway is connected to the corresponding water outlet connecting waterway, and the first water outlet is connected to the water outlet central waterway.

[0014] As a further technical solution of the present invention, the other ends of the multiple second branch waterways extend to the side walls of the multiple recesses of the bottom mold body, and one end of the multiple water outlet connecting waterways extends to the bottom walls of the multiple recesses of the bottom mold body. The cooling water channel of the bottom mold insert also includes a second inlet channel and a second outlet channel; One end of the third branch waterway extends through the second inlet waterway to the outer wall of the bottom mold insert and remains in communication with the corresponding second branch waterway; the other end of the third branch waterway extends through the second outlet waterway to the outer wall of the bottom mold insert and remains in communication with the first outlet waterway.

[0015] As a further technical solution of the present invention, the side wall of the bottom mold insert has a first insert recess, and one end of the second water inlet extends to the first insert recess; the bottom wall of the bottom mold insert has a second insert recess, and the other end of the second water outlet extends to the second insert recess.

[0016] Based on the split bottom mold structure provided above, the present invention also provides a technical solution for a blow molding die: A blow molding die, characterized in that it includes an upper clamping opening, a mold cavity structure, and the aforementioned split bottom mold structure; the upper clamping opening is located at the top of the mold cavity structure, and the split bottom mold structure is configured to jointly define a molding cavity with the mold cavity structure.

[0017] Based on the blow molding die provided above, the present invention also provides a technical solution for a blow molding method: A blow molding method using the aforementioned blow molding die includes a pre-blowing stage and a main blowing stage. In the pre-blowing stage, multiple bottom mold inserts of the blow molding die's bottom mold structure are in non-forming positions. In the main blowing stage, multiple bottom mold inserts are in forming positions.

[0018] The beneficial effects of this invention are as follows: By configuring multiple bottom mold inserts in the bottom mold body, these inserts can move synchronously along the longitudinal direction under the action of the driving component, thereby changing between the forming position and the non-forming position; during the pre-blowing stage, the multiple bottom mold inserts are in the non-forming position, and the bottom material of the preform will not cool down due to premature contact with the groove forming surface, thus maintaining the consistent ductility of the bottom material of the preform; after pre-blowing is completed, the driving device drives the multiple bottom mold inserts to move upward to the forming position, thereby maintaining the consistent ductility of the bottom material of the preform during blow molding, enabling it to flow more consistently under stretching action, forming a bottle bottom structure with uniform wall thickness, ensuring sufficient strength at all positions of the bottle bottom structure, not only guaranteeing the forming quality of the bottle bottom, but also reducing the material weight, which is beneficial to the lightweighting of plastic bottles; because the bottom material of the preform maintains ductility, the bottle bottom structure can be formed more easily, which is beneficial to reducing the blow molding pressure; and it conforms to the green concept of energy saving and material reduction. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the bottom mold structure of the bottom mold insert at the molding position in this embodiment; Figure 2 This is a schematic diagram of the bottom mold structure in the non-forming position of the bottom mold insert in this embodiment; Figure 3 This is a cross-sectional structural diagram of the bottom mold structure in this embodiment; Figure 4 This is a schematic diagram of the structure of the bottom mold body in this embodiment; Figure 5 This is a schematic diagram of the bottom mold insert in this embodiment; Figure 6 This is a schematic diagram of the structure of the driving component in this embodiment; Figure 7 This is an exploded view of the driving component in this embodiment; Figure 8 This is a schematic diagram of the internal structure of the bottom mold body in this embodiment; Figure 9 This is a schematic diagram of the internal structure of the bottom mold insert in this embodiment; Figure 10 This is a schematic diagram of the cooling water channel structure of the bottom mold body in this embodiment; Figure 11 This is a schematic diagram of the cooling water channel structure of the bottom mold insert in this embodiment. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0021] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, top, bottom, inside, outside, vertical, horizontal, longitudinal, counterclockwise, clockwise, circumferential, radial, rod-direction, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0022] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0023] like Figures 1 to 11As shown, this embodiment discloses a split bottom mold structure, including a bottom mold body 1, multiple bottom mold inserts 2, and a driving assembly 3; the bottom mold body 1 has a bottle bottom center forming surface 11 and multiple bottle bottom claw forming surfaces 12 arranged sequentially around the bottle bottom center forming surface 11, and the bottom mold body 1 has a bottom mold body recess 13 between two adjacent bottle bottom claw forming surfaces 12; wherein, the bottle bottom center forming surface 11 is used to form the bottle bottom center, and the bottle bottom claw forming surfaces 12 are used to form the bottle bottom claws; the multiple bottom mold inserts 2 are respectively formed with bottle bottom grooves. Surface 21, the bottle bottom groove forming surface 21, is used to form the bottle bottom groove. The driving component 3 is connected to multiple bottom mold inserts 2, driving the multiple bottom mold inserts 2 to move within multiple bottom mold body recesses 13 respectively. The multiple bottom mold inserts 2 can move to the forming position where the multiple bottle bottom groove forming surfaces 21, multiple bottle bottom claw forming surfaces 12, and the bottle bottom center forming surface 11 together form the bottle bottom forming surface. They can also move to a non-forming position where the multiple bottle bottom groove forming surfaces 21 are offset downward relative to the multiple bottle bottom claw forming surfaces 12 and the bottle bottom center forming surface 11. The multiple bottom mold inserts 2 are respectively and correspondingly arranged in the multiple bottom mold body recesses 13. Under the action of the driving component 3, the multiple bottom mold inserts 2 can move synchronously along the longitudinal direction, thereby changing between the forming position and the non-forming position. During the pre-blowing stage, multiple bottom mold inserts 2 are in non-forming positions. The material at the bottom of the preform corresponding to the bottom groove forming surface 21 cools down because it does not come into contact with the bottom groove forming surface 21 in advance, thus ensuring that the bottom material of the preform maintains consistent ductility. After pre-blowing is completed, the drive device 31 drives multiple bottom mold inserts 2 to move up to the forming position, thereby ensuring that the bottom material of the preform maintains consistent ductility during blow molding, and can flow relatively consistently under stretching action, forming a bottle bottom structure with uniform wall thickness, so that each position of the bottle bottom structure has sufficient strength, ensuring the forming quality of the bottle bottom.

[0024] Specifically, when multiple bottom mold inserts 2 are in the molding position, multiple bottle bottom groove molding surfaces 21, multiple bottle bottom claw-shaped surfaces 12 and bottle bottom center molding surfaces 11 are combined to form a bottle bottom molding surface for molding the bottom of a plastic bottle. When the multiple bottom mold inserts 2 are in the non-forming position, the multiple bottle bottom groove forming surfaces 21 are offset downward relative to the bottle bottom forming surface.

[0025] The positional changes of bottom mold insert 2 before and after blow molding are as follows: Before blow molding, multiple bottom mold inserts 2 are in non-molding positions; During the pre-blowing stage of blow molding, multiple bottom mold inserts 2 are in non-forming positions; During the main blow molding stage, multiple bottom mold inserts 2 are in the molding position.

[0026] Specifically, the drive assembly 3 includes a drive device 31 and a synchronous movement mechanism. The drive device 31 is connected to multiple bottom mold inserts 2 via the synchronous movement mechanism, driving the multiple bottom mold inserts 2 to move synchronously. The synchronous movement mechanism includes multiple connecting rods 32 and a connecting plate 33. The upper ends of the multiple connecting rods 32 are respectively connected to the multiple bottom mold inserts 2. The connecting plate 33 is located below the bottom mold body 1. The lower ends of the multiple connecting rods 32 are respectively connected to the connecting plate 33. The drive device 31 is installed on the outer wall of the bottom mold body 1, and the drive end of the drive device 31 is connected to the connecting plate 33. The bottom mold body 1 has multiple movable through holes 14. The movable through holes 14 connect the bottom mold body recess 13 and the outside of the bottom mold body 1. The movable through holes 14 allow the connecting rods 32 to move longitudinally. The lower ends of the multiple connecting rods 32 pass through the multiple movable through holes 14 and are connected to the connecting plate 33.

[0027] Specifically, the bottom of the bottom mold insert 2 has an insert recess 22, and the upper end of the connecting rod 32 is connected to a first connector 34. The first connector 34 is installed in the insert recess 22, and the upper end of the connecting rod 32 is connected to the bottom of the bottom mold insert 2 through the first connector 34. Specifically, the first connector 34 can be connected to the upper end of the connecting rod 32 by means of a threaded connection. The top surface of the connecting plate 33 has multiple connecting plate recesses 331, and the lower end of the connecting rod 32 is connected to a second connector 35. The second connector 35 is installed in the connecting plate recesses 331, and the lower end of the connecting rod 32 is connected to the top surface of the connecting plate 33 through the second connector 35. The number of connecting plate recesses 331 corresponds to the number of connecting rods 32. Each connecting plate recess 331 is equipped with a second connector 35. The second connector 35 is fixedly installed in the connecting plate recess 331 by a connector, which can be a bolt, screw or other fastening connector. The lower end of the connecting rod 32 is connected to the second connector 35 by a threaded connection, thereby vertically installing the connecting rod 32 on the top of the connecting plate 33.

[0028] Specifically, the side wall of the connecting plate 33 has a connecting plane 332, and the driving end of the driving device 31 is connected to the connecting plane 332. The side wall of the bottom mold body 1 has a mounting plane 15, and the driving device 31 is mounted on the mounting plane 15. The mounting plane 15 is flush with the connecting plane 332.

[0029] When the drive assembly 3 is working, the drive device 31 can drive the connecting plate 33 to move vertically up and down, thereby controlling the multiple bottom mold inserts 2 to change between the molding position and the non-molding position. In order to ensure the quality of plastic bottle molding, it is necessary to ensure that the bottom mold inserts 2 can accurately stop at the molding position and the non-molding position. Therefore, it is necessary to limit the movement stroke of the bottom mold inserts 2 so that they can accurately stop at the set molding position and the non-molding position. Specifically: during the upward movement of the connecting plate 33, the upper stroke is limited by the contact and cooperation between the top surface of the connecting plate 33 and the bottom surface of the bottom mold body 1. At this time, the multiple bottom mold inserts 2 are in the molding position. During the downward movement of the connecting plate 33, the lower stroke is limited by the contact and cooperation between the bottom surface of the bottom mold inserts 2 and the bottom surface of the bottom mold body recess 13. At this time, the multiple bottom mold inserts 2 are in the non-molding position. In this embodiment, the precise control of the position accuracy of the bottom mold inserts 2 can be achieved simply by setting the upper stroke limit and the lower stroke limit.

[0030] The bottom mold body 1 has a bottom mold body cooling channel 4, and multiple bottom mold inserts 2 each have a bottom mold insert cooling channel 5. The bottom mold body cooling channel 4 remains connected to the multiple bottom mold insert cooling channels 5 when the multiple bottom mold inserts 2 move. When the bottom mold inserts 2 move relative to the bottom mold body 1, the bottom mold body cooling channel 4 and the bottom mold insert cooling channels 5 remain connected, achieving precise and uniform cooling of each molding area of ​​the bottle bottom. This not only shortens the product cooling time and improves production efficiency, but also ensures the continuous and stable operation of the production process.

[0031] Specifically, the cooling water channel 4 of the bottom mold body and the cooling water channels 5 of multiple bottom mold inserts are connected by a flexible connecting component 6, which is configured to adapt to the positional changes of the bottom mold inserts 2 relative to the bottom mold body 1.

[0032] Specifically, the cooling water channel 4 of the bottom mold body includes a first inlet channel 41, a first outlet channel 42, multiple first branch channels 43, and multiple second branch channels 44. The first inlet channel 41 extends from the bottom wall of the bottom mold body 1 toward the center forming surface 11 of the bottle bottom; the first outlet channel 42 extends inward from the bottom wall of the bottom mold body 1; one end of each of the multiple first branch channels 43 is connected to the first inlet channel 41, the middle part extends along the trend of multiple bottle bottom claw forming surfaces 12, and the other end is connected to the first outlet channel 42; the multiple second branch channels 44 are alternately distributed with the multiple first branch channels 43 along the circumference, one end is connected to the first inlet channel 41, and the other end extends to connect with multiple bottom mold body recesses 13.

[0033] The bottom mold insert cooling channel 5 includes a third branch channel 51. One end of the third branch channel 51 extends to the outer wall of the bottom mold insert 2 and is connected to the corresponding second branch channel 44. The middle part extends along the trend of the bottle bottom groove forming surface 21, that is, the middle part of the third branch channel 51 extends with the shape of the bottle bottom groove forming surface 21, thereby providing a uniform cooling effect for the bottle bottom groove forming surface 21. The other end extends to the outer wall of the bottom mold insert 2 and is connected to the first outlet channel 42. The cooling water channel 4 of the bottom mold body also includes a water outlet central channel 45 and multiple water outlet connecting channels 46; the water outlet central channel 45 surrounds the bottom mold body 1 in a circumferential direction; one end of each of the multiple water outlet connecting channels 46 extends to connect with multiple bottom mold body recesses 13, and the other end connects to the water outlet central channel 45; the other end of each of the multiple first branch channels 43 connects to the water outlet central channel 45, the other end of the third branch channel 51 is connected to the corresponding water outlet connecting channel 46, and the first water outlet channel 42 connects to the water outlet central channel 45.

[0034] The other ends of multiple second branch water channels 44 extend to the side walls of multiple bottom mold body recesses 13 respectively, and one end of multiple water outlet connecting water channels 46 extends to the bottom wall of multiple bottom mold body recesses 13 respectively; the bottom mold insert cooling water channel 5 also includes a second water inlet channel 52 and a second water outlet channel 53; one end of the third branch water channel 51 extends through the second water inlet channel 52 to the outer wall of the bottom mold insert 2 and is connected to the corresponding second branch water channel 44, and the other end of the third branch water channel 51 extends through the second water outlet channel 53 to the outer wall of the bottom mold insert 2 and is connected to the first water outlet channel 42.

[0035] The flow path of the cooling medium in the bottom mold structure is as follows: The cooling medium enters from the bottom of the first inlet channel 41 and will be divided into multiple first branch channels 43 and multiple second branch channels 44. The cooling medium in the multiple first branch channels 43 flows into the outlet channel 45 and forms a confluence in the outlet channel 45. The cooling medium from multiple second branch water channels 44 flows into the second inlet water channel 52 of the corresponding connected bottom mold insert cooling water channel 5 through the flexible connecting component 6. After entering the second inlet water channel 52, the cooling medium flows through the third branch water channel 51 and then into the second outlet water channel 53. It then flows into the outlet water collection channel 45 through the flexible connecting component 6, where it also forms a confluence. The cooling medium in the centralized water outlet channel 45 eventually flows out through the bottom of the first water outlet channel 42.

[0036] In a preferred embodiment, the sidewall of the bottom mold insert 2 has a first insert recess 23, and one end of the second water inlet channel 52 extends to the first insert recess 23; the bottom wall of the bottom mold insert 2 has a second insert recess 24, and the other end of the second water outlet channel 53 extends to the second insert recess 24. By providing the first insert recess 23 and the second insert recess 24, even if the bottom mold insert 2 is in close contact with the bottom mold body recess 13 during movement, the first insert recess 23 and the second insert recess 24 can still provide accommodating space for the flexible connecting member 6, allowing the bottom mold insert 2 to move normally.

[0037] In a preferred embodiment, the flexible connecting component 6 is a telescopic hose. One end of the second inlet channel 52 is connected to the other end of the corresponding second branch channel 44 via the telescopic hose, and the other end of the second outlet channel 53 is connected to one end of the corresponding outlet connecting channel 46 via the telescopic hose. The telescopic hose has elasticity and flexibility, which allows the cooling water channel 4 of the bottom mold body and the multiple sets of cooling water channels 5 of the bottom mold insert to remain connected when the bottom mold insert 2 moves. Furthermore, the elasticity and flexibility of the telescopic hose can better accommodate the movement of the bottom mold insert 2, avoiding spatial interference between the bottom mold insert 2 and the telescopic hose when it moves.

[0038] In a preferred embodiment, each bottle bottom claw-shaped surface 12 includes a claw-shaped bottom surface 121 and a claw-shaped side surface 122. The middle portions of multiple first branch water channels 43 extend along the direction of the multiple claw-shaped bottom surface 121; that is, the middle portions of the first branch water channels 43 extend with the shape of the claw-shaped bottom surface 121, thereby providing a uniform cooling effect to the claw-shaped bottom surface 121. A groove bottom surface 123 is provided between two adjacent claw-shaped bottom surface 121, and multiple second branch water channels 44 extend along the direction of the multiple groove bottom surface 123; that is, the second branch water channels 44 extend with the shape of the groove bottom surface 123, thereby providing a uniform cooling effect to the groove bottom surface 123.

[0039] Based on the aforementioned split-type bottom mold structure, this embodiment also discloses a blow molding die, including an upper clamp, a mold cavity structure, and the aforementioned split-type bottom mold structure; the upper clamp is located at the top of the mold cavity structure, and the split-type bottom mold structure is configured to jointly define the molding cavity with the mold cavity structure. During the blow molding process, the upper clamp is used to place the support ring for the preform, the mold cavity structure is used to define the molding of the bottle body, and the split-type bottom mold structure is used to define the molding of the bottle bottom.

[0040] Based on the blow molding die disclosed above, this embodiment also discloses a blow molding method, which uses the blow molding die described above for blow molding; including a pre-blowing stage and a main blowing stage. In the pre-blowing stage, multiple bottom mold inserts of the bottom mold structure of the blow molding die are in non-forming positions; in the main blowing stage, multiple bottom mold inserts are in forming positions.

[0041] Specifically, as one implementation method, the following steps are included: Step 1, heating stage: Heat the preform to the stretching temperature; Step 2, mold closing stage: The heated preform is placed into the blow molding mold, the preform's support ring is placed at the upper clamp, the preform body is located inside the mold cavity structure, and the blow molding mold is closed. Step 3: The drive component 3 controls multiple bottom mold inserts 2 to move synchronously downwards along the longitudinal direction, so that the multiple bottom mold inserts 2 are in a non-forming position; Step four, pre-blowing stage: The stretching rod enters the preform along the rod direction to stretch the preform in the rod direction. At the same time, process gas that meets the gas pressure requirements of the preform stage is injected at the preform opening to stretch and pre-blow the preform simultaneously. During the pre-blowing process, multiple bottom mold inserts 2 are in non-forming positions. The stretching rod stretches the preform in the rod direction until the bottom of the preform contacts the center forming surface 11 of the bottle bottom, at which point the stretching rod stops. Step 5: Drive component 3 controls multiple bottom mold inserts 2 to move synchronously upward along the longitudinal direction, so that multiple bottom mold inserts 2 are in the forming position; Step six, main blowing stage: process gas that meets the pressure requirements of the main blowing stage is injected into the bottle preform opening to perform high-pressure blow molding of the bottle preform. During this blow molding process, multiple bottom mold inserts 2 are in the forming position; the bottle preform expands and tightly adheres to the inner wall of the mold cavity structure and the split bottom mold structure to form a plastic bottle. Step 7, mold opening stage: The tension rod retracts and returns to its original position, the mold cavity structure and the bottom mold structure separate from each other, and the plastic bottle is removed; Step 8: Simultaneously with the mold opening stage or between the mold opening stage and the next pre-blowing stage, the drive component 3 controls multiple bottom mold inserts 2 to move synchronously downwards along the longitudinal direction, so that the multiple bottom mold inserts 2 return to the non-forming position.

[0042] In the above blow molding method, during pre-blowing of the preform, multiple bottom mold inserts 2 are in non-forming positions, so that the bottom material of the preform will not cool down due to premature contact with the groove forming surface during the pre-blowing process. This ensures that the bottom material of the preform maintains consistent ductility, guarantees the molding quality of the plastic bottle, and also helps to reduce the blowing pressure and weight of the plastic bottle, which is in line with the green concept of energy conservation and material reduction.

[0043] The above description is only a preferred embodiment of the present invention. Any technical solution that achieves the purpose of the present invention by essentially the same means is within the protection scope of the present invention.

Claims

1. A split-type bottom mold structure, characterized in that: Includes the base mold body, multiple base mold inserts, and drive components; The bottom mold body has a central forming surface for the bottom of the bottle and a plurality of bottle bottom claw forming surfaces arranged sequentially around the central forming surface for the bottom of the bottle. The bottom mold body has a bottom mold body recess between two adjacent bottle bottom claw forming surfaces. Each of the plurality of bottom mold inserts has a bottle bottom groove forming surface. The driving component is connected to the plurality of bottom mold inserts and drives the plurality of bottom mold inserts to move within the recesses of the plurality of bottom mold bodies. The plurality of bottom mold inserts can be moved to a forming position where the plurality of bottle bottom groove forming surfaces, the plurality of bottle bottom claw forming surfaces, and the bottle bottom center forming surface together form a bottle bottom forming surface. They can also be moved to a non-forming position where the plurality of bottle bottom groove forming surfaces are offset downward relative to the plurality of bottle bottom claw forming surfaces and the bottle bottom center forming surface. The bottom mold body has a bottom mold body cooling channel, and the multiple bottom mold inserts each have a bottom mold insert cooling channel. The bottom mold body cooling channel can remain connected with the multiple bottom mold insert cooling channels when the multiple bottom mold inserts move.

2. The split-type bottom mold structure according to claim 1, characterized in that: The driving component includes a driving device and a synchronous moving mechanism. The driving device is connected to a plurality of bottom mold inserts through the synchronous moving mechanism, thereby driving the plurality of bottom mold inserts to move synchronously.

3. A split-type bottom mold structure according to claim 2, characterized in that: The synchronous movement mechanism includes multiple connecting rods and connecting plates; The upper ends of the multiple connecting rods are respectively connected to the multiple bottom mold inserts; The connecting plate is located below the bottom mold body; The lower ends of the multiple connecting rods are respectively connected to the connecting plate; The driving device is installed on the outer wall of the bottom mold body, and the driving end of the driving device is connected to the connecting plate.

4. A split-type bottom mold structure according to claim 1, characterized in that: The cooling channels of the bottom mold body and the cooling channels of the plurality of bottom mold inserts are connected by a flexible connecting member, which is configured to adapt to changes in the position of the bottom mold inserts relative to the bottom mold body.

5. A split-type bottom mold structure according to claim 4, characterized in that: The cooling water channels of the bottom mold body include: The first water inlet extends from the bottom wall of the bottom mold body toward the center forming surface of the bottle bottom; The first water outlet extends inward from the bottom wall of the bottom mold body; Multiple first branch water channels, one end of which is connected to the first inlet water channel, the middle part of which extends along the trend of the multiple bottle bottom claw-shaped surfaces, and the other end of which is connected to the first outlet water channel. Multiple second branch waterways are distributed alternately with multiple first branch waterways along the circumference, with one end connected to the first water inlet channel and the other end extending to connect with multiple recesses of the bottom mold body. The cooling water channels of the bottom mold insert include: The third branch water channel extends at one end to the outer wall of the bottom mold insert and remains connected to the corresponding second branch water channel. The middle part extends along the trend of the bottom groove forming surface, and the other end extends to the outer wall of the bottom mold insert and remains connected to the first outlet water channel.

6. A split-type bottom mold structure according to claim 5, characterized in that: The cooling water channel of the bottom mold body also includes: A water outlet channel surrounds the bottom mold body circumferentially. Multiple water outlet channels are connected, with one end extending to connect with multiple recesses of the bottom mold body, and the other end connecting to the water outlet central channel. The other ends of the multiple first branch waterways are respectively connected to the water outlet central waterway, the other end of the third branch waterway is connected to the corresponding water outlet connecting waterway, and the first water outlet is connected to the water outlet central waterway.

7. A split-type bottom mold structure according to claim 6, characterized in that: The other ends of the multiple second branch waterways extend to the side walls of the multiple recesses of the bottom mold body, and one end of the multiple water outlet connecting waterways extends to the bottom walls of the multiple recesses of the bottom mold body. The cooling water channel of the bottom mold insert also includes a second inlet channel and a second outlet channel; One end of the third branch waterway extends through the second inlet waterway to the outer wall of the bottom mold insert and remains in communication with the corresponding second branch waterway; the other end of the third branch waterway extends through the second outlet waterway to the outer wall of the bottom mold insert and remains in communication with the first outlet waterway.

8. A split-type bottom mold structure according to claim 7, characterized in that: The side wall of the bottom mold insert has a first insert recess, and one end of the second water inlet extends to the first insert recess; the bottom wall of the bottom mold insert has a second insert recess, and the other end of the second water outlet extends to the second insert recess.

9. A blow molding die, characterized in that: It includes an upper clamping opening, a mold cavity structure, and a split bottom mold structure as described in any one of claims 1-8; the upper clamping opening is located at the top of the mold cavity structure, and the split bottom mold structure is configured to jointly define a molding cavity with the mold cavity structure.

10. A blowing method, characterized in that: Blowing is performed using the blow molding die as described in claim 9; It includes a pre-blowing stage and a main-blowing stage. In the pre-blowing stage, multiple bottom mold inserts of the blow molding die bottom mold structure are in non-forming positions; in the main-blowing stage, multiple bottom mold inserts are in forming positions.

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