A multi-slider core-pulling demolding injection mold and a demolding method

Abstract

This invention discloses a multi-slider core-pulling demolding injection mold and demolding method. The injection mold includes a moving mold and a fixed mold. A product cavity is provided on the connecting mating surface of the fixed mold and the moving mold. The moving mold is equipped with a first core-pulling assembly, a second core-pulling assembly, and a first thread-unscrewing assembly, which respectively drive the first slider, the second slider, and the first threaded core to complete the forming and demolding of the left blind hole, the right blind hole, and the upper threaded blind hole of the product. The second slider is equipped with a radial core-pulling assembly and a second thread-unscrewing assembly. The radial core-pulling assembly drives a third slider to move radially along the second slider to form and demold the third blind hole on the inner wall of the second blind hole of the product. The second thread-unscrewing assembly drives the second threaded core to form and demold the second threaded blind hole on the product. This invention integrates multiple demolding mechanisms into the same slider, solving the problem of not being able to independently arrange multiple demolding components in a narrow space. The demolding sequence is rigorous, realizing fully automatic demolding of complex multi-directional hole products.

Description

Technical Field

[0001] This invention relates to the field of injection mold technology, specifically to a multi-slider core-pulling demolding injection mold and demolding method. Background Technology

[0002] Injection molds are tools used to produce plastic products, and they also give plastic products a complete structure and precise dimensions. Injection molding is a processing method used to mass-produce certain complex-shaped parts. Specifically, it refers to injecting heated and molten plastic into the mold cavity under high pressure by an injection molding machine, and then obtaining the molded product after cooling and solidification.

[0003] With the diversification of plastic products, the structure of injection molds is becoming increasingly complex. Figure 1 and Figure 2 A plastic product is shown, which has a first threaded blind hole 101 at the upper end, a first blind hole 102 on the left side, a second blind hole 103 and a second threaded blind hole 104 on the right side, and a third blind hole 105 on the inner wall of the second blind hole 103. For the injection mold used to produce this product, sliders or threaded cores need to be set at corresponding positions in the product cavity, and corresponding driving mechanisms such as hydraulic cylinders need to be installed on the outside of the mold to achieve core-pulling and demolding of the blind holes and threaded holes. However, the various blind holes and threaded blind holes in this plastic product are distributed on different end faces and have different directions. In particular, the distance between the second blind hole 103 and the second threaded blind hole 104 is only 10mm. Within such a narrow space, it is extremely difficult to both form the second threaded blind hole and achieve rotational demolding, and to form the third blind hole located on the inner wall of the second blind hole and achieve lateral core-pulling. This presents a significant challenge to the mold structure design. In existing technologies, the conventional approach is to set up independent sliders and drive mechanisms for each molding feature. However, within a narrow gap of 10mm, it is impossible to arrange two independent demolding components simultaneously, and the movement directions of each demolding component are perpendicular to each other, making interference highly likely. Therefore, how to achieve core-pulling demolding in two different directions (radial and axial) within the same narrow area, and coordinate the movement sequence of sliders and threaded cores in multiple directions and positions on the entire mold, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0004] To address some or all of the problems existing in the prior art, this invention provides a multi-slider core-pulling injection mold, comprising a moving mold and a fixed mold, wherein the moving mold and the fixed mold are openable and closable. A product cavity is provided on the mating surface of the fixed mold and the moving mold. The moving mold is provided with a first core-pulling assembly, a second core-pulling assembly, and a first descrewing assembly. A first slider is provided at the output end of the first core-pulling assembly, which drives one end of the first slider to extend into or out of the product cavity. A second slider is provided at the output end of the second core-pulling assembly, which drives one end of the second slider to extend into or out of the product cavity. A first threaded core is provided at the output end of the first descrewing assembly, which drives the first threaded core to rotate. The first tooth core extends into or out of the product cavity, and the movement directions of the first slider and the second slider are perpendicular to the mold opening and closing direction, respectively. The movement direction of the first tooth core is parallel to the mold opening and closing direction. The second slider is provided with a radial core-pulling assembly and a second thread-unscrewing assembly. The output end of the radial core-pulling assembly is provided with a third slider. The radial core-pulling assembly is used to drive the third slider to move radially along the second slider, and to cause the third slider to extend or retract from the outer wall of the second slider. The output end of the second thread-unscrewing assembly is provided with a second tooth core. The second thread-unscrewing assembly is used to drive the second tooth core to rotate, and to cause one end of the second tooth core to extend into or out of the product cavity. The movement direction of the second tooth core is perpendicular to the mold opening and closing direction.

[0005] As a further improvement of the present invention, the first core-pulling assembly includes a first hydraulic cylinder, which is connected to the fixed mold. A first driving block is provided on the output end of the first hydraulic cylinder, and the first slider is connected to the first driving block. A sliding guide groove is provided on the fixed mold, and the first driving block is slidably engaged with the sliding guide groove.

[0006] As a further improvement of the present invention, the first unscrewing assembly includes a second hydraulic cylinder, which is connected to the fixed mold. The output end of the second hydraulic cylinder is provided with a first rack, the fixed mold is provided with a first transmission gear, and the outer side wall of the first tooth core is provided with a first drive gear. The first transmission gear is meshed with the first drive gear and the first rack, respectively. The fixed mold is provided with a first synchronizer, and the end of the first tooth core away from the product cavity extends into the first synchronizer and is threadedly connected to the first synchronizer.

[0007] As a further improvement of the present invention, the fixed mold is provided with a demolding top plate, the demolding top plate is provided with a demolding ejector pin, the other end of the demolding ejector pin extends into the first tooth core, and the demolding top plate can drive the demolding ejector pin to move along the axial direction of the first tooth core, so that the demolding ejector pin extends into or extends out of the product cavity.

[0008] As a further improvement of the present invention, the second core-pulling assembly includes a third hydraulic cylinder, which is connected to the fixed mold. A second driving block is provided on the output end of the third hydraulic cylinder, and the second slider is connected to the second driving block.

[0009] As a further improvement of the present invention, the fixed mold is provided with two limit switches, and the third oil cylinder can drive the second drive block to abut against the limit switches. The limit switches are used to limit the movement stroke of the second slider.

[0010] As a further improvement of the present invention, the second drive block is provided with a plurality of positioning holes, and the moving mold is provided with anti-reverse seats at the corresponding positions of the positioning holes. After the mold is closed, the anti-reverse seats can be inserted into the corresponding positioning holes respectively.

[0011] As a further improvement of the present invention, the radial core-pulling assembly includes a push block and a shovel. The push block is slidably connected to the second drive block. The push block has an oblique hole, and the moving mold has an oblique guide post. The oblique guide post can be inserted into the oblique hole and slidably engaged with the oblique hole. The shovel is connected to the push block, and one end of the shovel can extend into the second slider. The side wall of the shovel has an oblique T-shaped groove, and the side wall of the third slider has a T-shaped locking block adapted to the oblique T-shaped groove. The T-shaped locking block is engaged with the oblique T-shaped groove. The third slider slides into the T-shaped groove and engages with it. One end of the third slider abuts against the second drive block. A core insert is provided on the side of the third slider away from the T-shaped engagement block. When the mold is opened, the sliding of the inclined guide post in the inclined hole can drive the push block to slide on the second drive block. The push block pulls the shovel to move synchronously, causing the shovel to move in the direction of extending out of the second slider. The shovel drives the third slider to move radially along the second slider through the inclined T-shaped groove and the inclined surface of the T-shaped engagement block, thereby causing the core insert to retract into the second slider.

[0012] As a further improvement of the present invention, the second unscrewing assembly includes a fourth hydraulic cylinder, which is connected to the second drive block. A second rack is provided on the output end of the fourth hydraulic cylinder, a second transmission gear is provided on the second drive block, and a second drive gear is provided on the outer side wall of the second tooth core. The second transmission gear is meshed with the second drive gear and the second rack, respectively. A second synchronizer is provided on the second drive block, and one end of the second tooth core away from the product cavity extends into the second synchronizer and is threadedly connected to the second synchronizer.

[0013] On the other hand, the present invention also provides a demolding method for the above-mentioned multi-slider core-pulling injection molded plastic parts, comprising the following steps: Mold opening: After the product injection molding is completed in the product cavity, the moving mold is driven to move away from the fixed mold, so that the moving mold and the fixed mold are separated. In the radial core pulling process, as the moving mold moves away from the fixed mold, the moving mold drives the inclined guide post to move synchronously. The inclined guide post drives the push block to slide on the second drive block. The push block pulls the shovel to move synchronously. The shovel drives the third slider to move radially along the second slider, thereby causing the core insert to retract into the second slider. To remove the small thread, the fourth oil cylinder is activated, driving the second rack to move. The second rack drives the second transmission gear meshing with it to rotate, and the second transmission gear drives the second tooth core to rotate synchronously until the second tooth core rotates and extends out of the product cavity. The combined core pulling mechanism activates the third hydraulic cylinder, driving the second drive block to move in the direction of extending out of the product cavity. The second drive block drives the second slider, the radial core pulling assembly, and the second unscrewing assembly to move synchronously until the second slider extends out of the product cavity. On the opposite side, the first hydraulic cylinder is activated, driving the first drive block to move in the direction of extending out of the product cavity. The first drive block drives the first slider to move synchronously until the first slider extends out of the product cavity. To remove the large thread, start the second oil cylinder, drive the first rack to move, the first rack drives the first transmission gear meshing with it to rotate, the first transmission gear drives the first tooth core to rotate synchronously, until the first tooth core rotates and extends out of the product cavity; When the product is ejected, the ejector plate moves, and the ejector plate drives the ejector pins to move synchronously, so that the ejector pins extend into the product cavity and eject the product out of the cavity.

[0014] Compared with the prior art, the beneficial effects of the present invention are: First, this invention solves the problem of not being able to independently set up two demolding mechanisms within extremely small gaps by integrating a radial core-pulling assembly and a second unscrewing assembly on the second slider. The radial core-pulling assembly drives the third slider to retract radially, and the second unscrewing assembly drives the second tooth core to rotate and exit. The two operate sequentially and share the installation space of the second slider, resulting in a compact structure that achieves orderly demolding in three mutually perpendicular directions within a narrow area.

[0015] Secondly, the overall layout of the mold in this invention is reasonable, with the movement directions of each core-pulling and thread-unscrewing component avoiding each other and preventing interference. The movement directions of the first and second sliders are perpendicular to the mold opening and closing direction, and are used to form blind holes on the left and right sides of the product, respectively; the movement direction of the first tooth core is parallel to the mold opening and closing direction, and is used to form the threaded blind hole at the top of the product; while the movement direction of the second tooth core is perpendicular to the mold opening and closing direction and is integrated on the second slider. Through this differentiated movement direction design in three-dimensional space, multiple demolding actions can be carried out in an orderly manner in different planes without interfering with each other, thereby realizing the simultaneous one-time molding and automatic demolding of five different orientations and angles on a single mold, greatly improving the integration of the mold and production efficiency. Attached Figure Description

[0016] To more clearly illustrate the solutions in this invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the product structure processed according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the product processed according to another embodiment of the present invention. Figure 3 This is a schematic diagram of the mold opening state structure in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the moving mold in an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the first core-pulling assembly in an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of the first unscrewing assembly in an embodiment of the present invention; Figure 7 This is a schematic diagram of the structure of the second core-pulling assembly in an embodiment of the present invention; Figure 8 This is a schematic diagram of the structure of the second unscrewing assembly 5 in an embodiment of the present invention; Figure 9This is a schematic diagram of the combined structure of the shovel and the third slider in an embodiment of the present invention; Figure 10 This is a schematic diagram of the structure of the second unscrewing assembly in an embodiment of the present invention. Detailed Implementation

[0018] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings are used to distinguish different objects, not to describe a particular order.

[0019] In this invention, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment to other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention can be combined with other embodiments.

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0021] like Figure 1-10 As shown, a multi-slider core-pulling injection mold includes a moving mold 100 and a fixed mold 200. The moving mold 100 and the fixed mold 200 are closable; in the closed state, a closed product cavity 300 for molding plastic products is formed on the mating surface of the moving mold 100 and the fixed mold 200, and the shape of the product cavity 300 is consistent with the shape of the plastic product to be molded.

[0022] The moving mold 100 is equipped with a first core-pulling assembly 1, a second core-pulling assembly 2, and a first thread-unscrewing assembly 3. The output end of the first core-pulling assembly 1 is connected to a first slider 11, which drives one end of the first slider 11 to vertically extend into or out of the product cavity 300, thereby forming the first blind hole 102 on the left side of the product. The output end of the second core-pulling assembly 2 is connected to a second slider 21, which drives one end of the second slider 21 to vertically extend into or out of the product cavity 300, thereby forming the second blind hole 103 on the right side of the product. The output end of the first thread-unscrewing assembly 3 is connected to a first threaded core 31, which drives the first threaded core 31 to rotate and move in a direction parallel to the mold opening and closing direction, thereby forming and unscrewing the first threaded blind hole 101 at the upper end of the product. With this layout, the movement direction of the first slider 11 and the second slider 21 is set to be perpendicular to the mold opening and closing direction, while the movement direction of the first tooth core 31 is parallel to the mold opening and closing direction. It should be noted that by setting the movement direction of the first slider 11 and the second slider 21 to be perpendicular to the mold opening and closing direction, and setting the movement direction of the first tooth core 31 to be parallel to the mold opening and closing direction, regional demolding of holes in different orientations in three-dimensional space is realized, avoiding motion interference.

[0023] The second slider 21 also integrates a radial core-pulling assembly 4 and a second unscrewing assembly 5. The output end of the radial core-pulling assembly 4 is connected to a third slider 41. The radial core-pulling assembly 4 can drive the third slider 41 to move radially along the second slider 21 (i.e., in a plane perpendicular to the direction of movement of the second slider 21), and cause the third slider 41 to extend or retract from the outer wall of the second slider 21. This design allows the core-pulling of the lateral small hole to be completed first in a confined space. At the same time, the output end of the second unscrewing assembly 5 is connected to a second threaded core 51. The second unscrewing assembly 5 can drive the second threaded core 51 to rotate and move it in a direction perpendicular to the mold opening and closing direction (i.e., parallel to the direction of movement of the second slider 21), so that one end of the second threaded core 51 extends into or out of the product cavity 300 to form and release the second threaded blind hole 104. The radial core-pulling assembly 4 and the second unscrewing assembly 5 are all integrated on the second slider 21, so that they can move together with the second slider 21 as a whole. This completes the demolding action in two mutually perpendicular directions within a limited space, solving the technical problem that the demolding mechanism cannot be set up separately due to the small spacing.

[0024] Specifically, such as Figure 5As shown, the first core-pulling assembly 1 includes a first hydraulic cylinder 12. The first hydraulic cylinder 12 is fixedly connected to the fixed mold 200, and its output end is connected to a first drive block 13. The first slider 11 is fixed to the first drive block 13. To ensure the movement accuracy and stability of the first slider 11 during long-distance core pulling, a sliding guide groove 14 is specially machined on the fixed mold 200, and the first drive block 13 is slidably engaged with the sliding guide groove 14. During operation, the piston rod of the first hydraulic cylinder 12 extends and retracts, pushing the first drive block 13 to reciprocate along the sliding guide groove 14, and the first drive block 13 drives the first slider 11 to move synchronously. The sliding guide groove 14 forcibly limits and guides the movement direction of the first drive block 13, preventing wobbling or jamming due to excessive overhang of the first slider 11, ensuring the movement stability and positional accuracy during long-distance core pulling, and improving the reliability of the mold.

[0025] like Figure 6As shown, the first unscrewing assembly 3 includes a second hydraulic cylinder 32, a first rack 33, a first transmission gear 34, a first drive gear 35, and a first synchronizer 36. The second hydraulic cylinder 32 is fixedly mounted on the fixed mold 200, and the first rack 33 is fixedly connected to the output end of the second hydraulic cylinder 32. The length direction of the first rack 33 is consistent with the extension and retraction direction of the second hydraulic cylinder 32, and the tooth surface of the first rack 33 faces the first transmission gear 34. The first transmission gear 34 is rotatably mounted on the fixed mold 200 through a rotating shaft and bearings, and the teeth of the first transmission gear 34 mesh with the first rack 33 and the first drive gear 35 respectively. The first drive gear 35 is fixedly sleeved on the outer wall of the first tooth core 31. One end of the first tooth core 31 is used to extend into the forming thread blind hole of the product cavity 300, and the other end extends into the interior of the first synchronizer 36. The first synchronizer 36 is a sleeve-shaped part with internal threads machined on its inner wall. It is fixedly mounted on the fixed mold 200. The outer wall of the first toothed core 31, away from the product cavity 300, is machined with external threads. These external threads engage with the internal threads of the first synchronizer 36 to form a threaded connection. When the second hydraulic cylinder 32 operates, its piston rod extends or retracts, driving the first rack 33 to perform linear reciprocating motion. The first rack 33 drives the first transmission gear 34, which meshes with it, to rotate. The first transmission gear 34 then transmits the rotational motion to the first drive gear 35, thereby driving the first toothed core 31 to rotate synchronously. Because the first toothed core 31 is threadedly engaged with the fixed first synchronizer 36, the first toothed core 31 will inevitably undergo axial displacement while rotating, that is, it will move in a direction parallel to the opening and closing of the mold. Specifically, when the second hydraulic cylinder 32 drives the first rack 33 to move in one direction, the first tooth core 31 rotates and moves forward (towards the product cavity 300), thus extending into the product cavity 300; when the first rack 33 moves in the opposite direction, the first tooth core 31 rotates and moves backward, thus exiting the product cavity 300. By controlling the stroke and direction of the second hydraulic cylinder 32, the number of rotations and axial displacement of the first tooth core 31 can be precisely controlled, completing the forming and demolding of the first threaded blind hole 101. The advantages of this gear and rack combined with a synchronizer thread demolding structure are: precise transmission ratio, ensuring that the angle of rotation and axial movement distance of the first tooth core 31 correspond strictly each time, without slippage or jamming; at the same time, the gear and rack transmission has a large torque output capacity, suitable for driving thicker tooth cores or longer threads for demolding; in addition, the entire transmission mechanism is externally mounted on the fixed mold 200, facilitating maintenance and adjustment.

[0026] In specific implementation, the first transmission gear 34 can be multiple meshing gear sets. The specific number of gears and the gear ratio can be adaptively adjusted according to actual needs, and the present invention does not limit this.

[0027] like Figure 7As shown, the second core-pulling assembly 2 includes a third hydraulic cylinder 22 and a second drive block 23. The third hydraulic cylinder 22 is fixedly mounted on the moving mold 100, and the second drive block 23 is fixedly connected to the output end of the third hydraulic cylinder 22. The second slider 21 is fixedly connected to the second drive block 23. When the third hydraulic cylinder 22 is working, the piston rod extends or retracts, driving the second drive block 23 to reciprocate. The second drive block 23 drives the second slider 21 to move synchronously, thereby causing the second slider 21 to extend into or exit the product cavity 300, completing the forming and core-pulling of the second blind hole 103. Since the second slider 21 also integrates a radial core-pulling assembly 4 and a second unscrewing assembly 5, the second drive block 23 is actually the mounting base for the entire second slider 21 and its auxiliary components, and its motion accuracy and stability are crucial.

[0028] To improve the level of automated control of the movement of the second slider 21, two limit switches 24 are installed on the fixed mold 200. These two limit switches 24 are located at the two extreme positions of the movement stroke of the second drive block 23. During the movement of the second drive block 23 driven by the third cylinder 22, when the second drive block 23 comes into contact with one of the limit switches 24, the limit switch 24 sends an electrical signal to the injection molding machine's control system. The control system then controls the third cylinder 22 to stop working, thereby achieving precise limiting of the movement stroke. Specifically, in the mold-closed state, the second drive block 23 abuts against the limit switch 24 near the product cavity 300. At this time, the second slider 21 has fully extended into place, and injection molding can begin. During the demolding process after mold opening, the third cylinder 22 drives the second drive block 23 to move away from the product cavity 300. When the second drive block 23 moves to the other end and abuts against another limit switch 24, the limit switch 24 sends a signal, and the third cylinder 22 stops. At this time, the second slider 21 is completely pulled out of the product cavity 300. The mold-closing process is the opposite: the third cylinder 22 drives the second drive block 23 to reset until it touches the first limit switch 24. Through the precise control of the limit switch 24, it can be ensured that the second slider 21 can accurately stop at the predetermined position each time, avoiding mold collision due to over-travel or product failure due to insufficient travel, significantly improving the automation level and operational reliability of the mold.

[0029] like Figure 4 , Figure 7As shown, considering that the molten plastic is injected into the product cavity 300 under high pressure during the injection molding process, it will generate a huge lateral thrust on the second slider 21. This thrust may cause the second drive block 23 and the second slider 21 to retract, resulting in an increase in the size of the molded product or the formation of flash, affecting product quality. Therefore, multiple positioning holes 25 are provided on the second drive block 23, distributed at different positions. Anti-reverse seats 6 are respectively provided on the moving mold 100 at corresponding positions of these positioning holes 25. The anti-reverse seats 6 are cylindrical or conical bosses protruding from the surface of the moving mold 100. In the mold-closed state, the anti-reverse seats 6 can be inserted into the corresponding positioning holes 25 to form a tight mechanical fit. When the injection pressure acts on the second slider 21 and attempts to push the second drive block 23 backward, the mating surface of the anti-reverse seat 6 and the positioning hole 25 will bear this thrust, thereby preventing the second drive block 23 from moving. This anti-reverse structure is equivalent to adding a mechanical locking to the second drive block 23, ensuring that its position is absolutely fixed during the injection molding process.

[0030] like Figure 8 , Figure 9As shown, the radial core-pulling assembly 4 includes a push block 42 and a scraper 43. The push block 42 is slidably connected to the second drive block 23. The push block 42 has an oblique hole 44, the centerline of which is inclined at a certain angle relative to the horizontal plane, typically between 15 and 30 degrees. An oblique guide post 45 is fixedly mounted on the moving mold 100, the angle of which matches the angle of the oblique hole 44. In the mold-closed state, the oblique guide post 45 is inserted into the oblique hole 44, with a sliding gap maintained between them. One end of the scraper 43 is fixedly connected to the push block 42, and the other end of the scraper 43 can extend into the second slider 21. An oblique T-shaped groove 46 is machined on the side wall of the scraper 43, the extension direction of which forms a certain angle with the movement direction of the scraper 43. The side wall of the third slider 41 is machined with a T-shaped locking block 47 that perfectly matches the shape of the inclined T-shaped groove 46. The T-shaped locking block 47 can be inserted into the inclined T-shaped groove 46 and slide along the inclined T-shaped groove 46. One end of the third slider 41 abuts against the second drive block 23, that is, the second drive block 23 provides limiting and support for the third slider 41. A core insert 48 is provided on the side of the third slider 41 away from the T-shaped locking block 47. The core insert 48 is used to form the third blind hole 105. When the injection molding is completed and the mold opening begins, the moving mold 100 moves away from the fixed mold 200 under the drive of the injection molding machine. Since the inclined guide post 45 is fixed on the moving mold 100, and the push block 42 is disposed on the second drive block 23 (the second drive block 23 has not yet moved), the inclined guide post 45 moves upward with the moving mold 100. The relative movement between the inclined guide post 45 and the inclined hole 44 forces the push block 42 to slide away from the product cavity 300 on the second drive block 23. When the push block 42 moves, it pulls the shovel 43, which is fixedly connected to it, to move synchronously. The shovel 43 is pulled outward from inside the second slider 21. As the excavator 43 moves outward, the inclined T-shaped groove 46 on its side wall also moves outward synchronously. This inclined T-shaped groove 46 pushes the T-shaped locking block 47 through its inclined surface. Since the T-shaped locking block 47 is fixedly connected to the third slider 41, and one end of the third slider 41 is blocked by the second drive block 23 and cannot move outward, the inclined surface of the inclined T-shaped groove 46 pushes the T-shaped locking block 47 and the third slider 41 in a direction perpendicular to the movement direction of the excavator 43 (i.e., the radial direction of the second slider 21). Specifically, the third slider 41 moves in a direction that retracts into the second slider 21, causing the core insert 48 to exit from the third blind hole 105. When the moving mold 100 continues to rise to the fully open state, the third slider 41 completely retracts into the second slider 21, at which point the core-pulling action of the third blind hole 105 is completed. The biggest advantage of this radial core-pulling assembly 4 is that it fully utilizes the power of the mold opening action itself to drive the radial movement of the third slider 41, without the need for additional hydraulic or pneumatic cylinders, thus saving installation space and manufacturing costs.Meanwhile, the cooperation between the inclined guide post 45 and the inclined hole 44, as well as the cooperation between the inclined T-shaped slide 46 and the T-shaped locking block 47, converts the vertical linear motion into the horizontal radial motion twice, realizing the lateral core pulling in a narrow space (inside the second slider 21). The structure is extremely compact and the transmission is reliable.

[0031] like Figure 10 As shown, the second unscrewing assembly 5 integrated on the second slider 21 includes a fourth cylinder 52, a second rack 53, a second transmission gear 54, a second drive gear 55, and a second synchronizer 56. The fourth cylinder 52 is fixedly mounted on the second drive block 23, so the fourth cylinder 52 can move as a whole with the second drive block 23. The second rack 53 is fixedly connected to the output end of the fourth cylinder 52. The length direction of the second rack 53 is consistent with the extension and retraction direction of the fourth cylinder 52. The second transmission gear 54 is rotatably mounted on the second drive block 23 via bearings. The second transmission gear 54 meshes with the second rack 53 and the second drive gear 55, which is fixedly sleeved on the outer wall of the second tooth core 51. The second synchronizer 56 is a sleeve part with internal threads machined on its inner wall. It is fixedly mounted on the second drive block 23. The end of the second tooth core 51 away from the product cavity 300 is machined with external threads, which mate with the internal threads of the second synchronizer 56 to form a threaded connection. The other end of the second threaded core 51 is used to extend into the product cavity 300 to form the second threaded blind hole 104. When it is necessary to disengage from the second threaded blind hole 104, the fourth hydraulic cylinder 52 drives the second rack 53 to move linearly. The second rack 53 drives the second transmission gear 54 to rotate, and the second transmission gear 54 then drives the second drive gear 55 and the second threaded core 51 to rotate synchronously. Since the second threaded core 51 is threadedly engaged with the second synchronizer 56 fixed on the second drive block 23, the second threaded core 51 will inevitably be displaced along its axial direction while rotating. Because the direction of movement of the second threaded core 51 is perpendicular to the mold opening and closing direction, that is, it moves in the horizontal direction, the axial movement direction of the second threaded core 51 is also horizontal. By controlling the direction of movement of the fourth hydraulic cylinder 52, the second threaded core 51 can be moved away from the product cavity 300, thereby rotating out of the second threaded blind hole 104. Similar to the first unscrewing assembly 3, this structure also adopts a gear and rack engagement synchronizer transmission method, which has the advantages of precise transmission, large torque, and reliable demolding. The entire second unscrewing assembly 5 is installed on the second drive block 23, so that the second thread core 51 and the second slider 21 become a whole. Before the second slider 21 is completely withdrawn from the second blind hole 103, the second thread core 51 can be driven to complete the rotation demolding of the small thread. The two do not interfere with each other in space, which perfectly solves the problem of both unscrewing and core pulling within a 10 mm gap.

[0032] In specific implementation, the second transmission gear 54 can also be multiple meshing gear sets. The specific number of gears and the gear ratio can be adapted according to actual needs, and the present invention does not limit this.

[0033] like Figure 6 As shown, after all the sliders have been pulled out, the product may still remain attached to the product cavity 300. Therefore, a demolding ejector plate 7 is provided on the fixed mold 200. The demolding ejector plate 7 is a plate-shaped part installed on the back of the fixed mold 200 and is directly connected to the ejector roller of the injection molding machine during processing. Multiple demolding ejector pins 8 are fixedly installed on the side of the demolding ejector plate 7 facing the product cavity 300. The other ends of these demolding ejector pins 8 pass through the central hole inside the first toothed core 31 and can extend into the product cavity 300. The first toothed core 31 is designed as a hollow structure, with the central hole extending through its entire length. The demolding ejector pins 8 can slide freely axially within the first toothed core 31, allowing them to extend into or out of the product cavity 300. After all core pulling and thread removal actions are completed, the ejector roller of the injection molding machine pushes the demolding plate 7 forward. The demolding plate 7 drives the demolding pins 8 to move forward synchronously. The ends of the demolding pins 8 extend from the first toothed core 31 and press against the surface of the product, ejecting the product from the product cavity 300, thus completing the product demolding. Since the demolding pins 8 are located inside the first toothed core 31, the hollow space of the first toothed core 31 is fully utilized, eliminating the need to open additional ejector pin holes on the fixed mold 200, thus simplifying the mold structure. At the same time, the ejection direction of the demolding pins 8 is consistent with the axial direction of the first toothed core 31, which can smoothly push the product out and avoid deformation or damage caused by uneven force on the product.

[0034] Based on the above-mentioned multi-slider core-pulling injection mold, the present invention also provides a demolding method for molding plastic parts using the above-mentioned multi-slider core-pulling injection mold, the demolding method comprising the following steps: Mold opening. After the product is injection molded and cooled and solidified in the product cavity 300, the injection molding machine drives the moving mold 100 to move vertically upward away from the fixed mold 200, so that the moving mold 100 and the fixed mold 200 are completely separated. The mold opening action is the beginning of the entire demolding process, providing the necessary movement space for the subsequent movement of each core-pulling component.

[0035] Radial core pulling. During the mold opening process, i.e., as soon as the moving mold 100 begins to move upward, the radial core pulling action automatically begins. The moving mold 100 drives the inclined guide post 45 fixed thereon to move upward synchronously. The inclined guide post 45 slides in the inclined hole 44 on the push block 42. Since the direction of the inclined hole 44 is not parallel to the mold opening direction, the upward movement of the inclined guide post 45 forces the push block 42 to slide away from the product cavity 300 on the second drive block 23. The push block 42 pulls the shovel 43 fixedly connected to it to move synchronously, and the shovel 43 is pulled out from inside the second slider 21. While the shovel 43 moves outward, the inclined T-shaped groove 46 on its side wall pushes the T-shaped locking block 47 on the third slider 41 through the inclined surface action, causing the third slider 41 to move inward along the radial direction of the second slider 21 (i.e., perpendicular to the movement direction of the second slider 21), thereby causing the core insert 48 at the end of the third slider 41 to retract into the second slider 21. At this point, the third blind hole 105, formed on the inner wall of the second blind hole 103, has completed core pulling and demolding. The key to this step is that radial core pulling must be completed before the second slider 21 is completely pulled out; otherwise, the core insert 48 will interfere with the product, causing product damage or mold tearing. Using the mold opening action to directly drive radial core pulling not only saves power but also ensures the sequential nature of the actions.

[0036] Unscrew the small thread. After mold opening is completed, start the fourth hydraulic cylinder 52. The fourth hydraulic cylinder 52 drives the second rack 53 to move linearly, the second rack 53 drives the second transmission gear 54 to rotate, and the second transmission gear 54 drives the second thread core 51 to rotate synchronously through the second drive gear 55. Since the second thread core 51 is threadedly connected to the second synchronizer 56 fixed on the second drive block 23, the second thread core 51 moves axially away from the product cavity 300 while rotating, and completely rotates out of the second thread blind hole 104.

[0037] Combined core pulling. After the small thread is removed, the third hydraulic cylinder 22 is activated. The third hydraulic cylinder 22 drives the second drive block 23 to move horizontally in the direction extending out of the product cavity 300. The second drive block 23 drives the second slider 21, which is fixedly connected to it, to move synchronously. Since the radial core pulling assembly 4 (the third slider 41 has retracted) and the second thread removal assembly 5 (the second thread core 51 has been withdrawn) are both mounted on the second drive block 23 or the second slider 21, they move backward as a whole with the second drive block 23, so that the main body of the second slider 21 is completely pulled out of the second blind hole 103 of the product. This step completes the main core pulling of the second blind hole 103, and is also the core step for demolding the entire right side area of ​​the product. The beneficial effect of combined core pulling is that multiple components are integrated on the same motion platform, and multiple parts can be pulled together in a single drive, simplifying the control logic and improving demolding efficiency.

[0038] Conversely, during or after the combined core pulling process, the first hydraulic cylinder 12 is activated. The first hydraulic cylinder 12 drives the first drive block 13 to move horizontally along the sliding guide groove 14 towards the direction extending out of the product cavity 300. The first drive block 13 drives the first slider 11 to move synchronously, so that the first slider 11 is completely pulled out from the first blind hole 102 on the left side of the product. Since the left blind hole is independent of the right side structure, this step can be performed in parallel with the combined core pulling to save overall demolding time.

[0039] After the large thread is removed and the core is pulled out from the opposite side, the second hydraulic cylinder 32 is activated. The second hydraulic cylinder 32 drives the first rack 33 to move linearly, and the first rack 33 drives the first transmission gear 34 to rotate. The first transmission gear 34 drives the first threaded core 31 to rotate synchronously through the first drive gear 35. With the threaded engagement between the first threaded core 31 and the first synchronizer 36 fixed on the fixed mold 200, the first threaded core 31 moves vertically upward along its axial direction away from the product cavity 300 while rotating, and completely rotates out of the first threaded blind hole 101 at the upper end of the product. This step completes the demolding of the last molding feature of the product. Since the movement direction of the first threaded core 31 is vertical, while the movement direction of all the previous sliders is horizontal, no interference will occur.

[0040] Product ejection. After all sliders and cores have completely exited the product cavity 300, the ejector roller of the injection molding machine moves forward, pushing the demolding ejector plate 7. The demolding ejector plate 7 drives the demolding pin 8 fixed thereon to move vertically forward along the axial direction of the first core 31 towards the product cavity 300. The end of the demolding pin 8 passes through the central hole of the first core 31 and presses against the product surface, smoothly ejecting the product from the product cavity 300. At this point, the entire demolding process is complete, and the product can be removed from the mold.

[0041] The entire demolding method achieves fully automated, high-efficiency, and manual-free production, and is especially suitable for mass injection molding of complex plastic products with multiple anisotropic holes and narrow-spacing threaded blind holes.

[0042] The specific embodiments described above are preferred embodiments of the present invention and are not intended to limit the specific scope of the present invention. The scope of the present invention includes, but is not limited to, these specific embodiments. All equivalent changes made in accordance with the present invention are within the protection scope of the present invention.

Claims

1. A multi-slider core-pulling injection mold, characterized in that: The device includes a moving mold and a fixed mold, which are openable and closable. A product cavity is provided on the mating surface of the fixed mold and the moving mold. The moving mold is provided with a first core-pulling assembly, a second core-pulling assembly, and a first unscrewing assembly. A first slider is provided at the output end of the first core-pulling assembly, which drives one end of the first slider to extend into or out of the product cavity. A second slider is provided at the output end of the second core-pulling assembly, which drives one end of the second slider to extend into or out of the product cavity. A first thread is provided at the output end of the first unscrewing assembly, which drives the first thread to rotate, causing one end of the first thread to extend into or out of the product cavity. The movement directions of the first slider and the second slider are perpendicular to the direction of mold opening and closing, respectively, and the movement direction of the first thread is parallel to the direction of mold opening and closing. The second slider is provided with a radial core-pulling assembly and a second unscrewing assembly. The output end of the radial core-pulling assembly is provided with a third slider. The radial core-pulling assembly is used to drive the third slider to move radially along the second slider, so that the third slider extends out or retracts from the outer side wall of the second slider. The output end of the second unscrewing assembly is provided with a second tooth core. The second unscrewing assembly is used to drive the second tooth core to rotate, so that one end of the second tooth core extends into or out of the product cavity. The direction of movement of the second tooth core is perpendicular to the direction of mold opening and closing.

2. The multi-slider core-pulling demolding injection mold according to claim 1, characterized in that: The first core-pulling assembly includes a first hydraulic cylinder, which is connected to the fixed mold. A first driving block is provided on the output end of the first hydraulic cylinder, and the first slider is connected to the first driving block. The fixed mold is provided with a sliding guide groove, and the first driving block is slidably engaged with the sliding guide groove.

3. The multi-slider core-pulling demolding injection mold according to claim 2, characterized in that: The first unscrewing assembly includes a second hydraulic cylinder connected to the fixed mold. The output end of the second hydraulic cylinder is provided with a first rack. The fixed mold is provided with a first transmission gear. The outer side wall of the first tooth core is provided with a first drive gear. The first transmission gear is meshed with the first drive gear and the first rack respectively. The fixed mold is provided with a first synchronizer. The end of the first tooth core away from the product cavity extends into the first synchronizer and is threadedly connected to the first synchronizer.

4. The multi-slider core-pulling demolding injection mold according to claim 3, characterized in that: The fixed mold is provided with a demolding top plate, and the demolding top plate is provided with a demolding ejector pin. The other end of the demolding ejector pin extends into the first tooth core, and the demolding top plate can drive the demolding ejector pin to move along the axial direction of the first tooth core, so that the demolding ejector pin extends into or extends out of the product cavity.

5. The multi-slider core-pulling demolding injection mold according to claim 4, characterized in that: The second core-pulling assembly includes a third hydraulic cylinder, which is connected to the fixed mold. A second drive block is provided on the output end of the third hydraulic cylinder, and the second slider is connected to the second drive block.

6. The multi-slider core-pulling injection mold according to claim 5, characterized in that: The fixed mold is equipped with two limit switches. The third hydraulic cylinder can drive the second drive block to abut against the limit switches. The limit switches are used to limit the movement stroke of the second slider.

7. The multi-slider core-pulling injection mold according to claim 5, characterized in that: The second drive block is provided with multiple positioning holes, and the moving mold is provided with anti-reverse seats at the corresponding positions of the positioning holes. After the mold is closed, the anti-reverse seats can be inserted into the corresponding positioning holes.

8. The multi-slider core-pulling injection mold according to claim 5, characterized in that: The radial core-pulling assembly includes a push block and a scraper. The push block is slidably connected to the second drive block. The push block has an oblique hole. The moving mold has an oblique guide post that can be inserted into the oblique hole and slidably engaged with the oblique hole. The scraper is connected to the push block. One end of the scraper can extend into the second slider. The side wall of the scraper has an oblique T-shaped groove. The side wall of the third slider has a T-shaped locking block that matches the oblique T-shaped groove. The T-shaped locking block slidably engages with the oblique T-shaped groove. One end of the third slider abuts against the second drive block. The side of the third slider away from the T-shaped locking block has a core insert. When the mold is opened, the sliding of the inclined guide post in the inclined hole can drive the push block to slide on the second drive block. The push block pulls the shovel to move synchronously, so that the shovel moves in the direction of extending out of the second slider. The shovel drives the third slider to move radially along the second slider through the inclined T-shaped groove and the inclined surface of the T-shaped locking block, so that the core insert retracts into the second slider.

9. The multi-slider core-pulling demolding injection mold according to claim 8, characterized in that: The second unscrewing assembly includes a fourth hydraulic cylinder connected to the second drive block. The output end of the fourth hydraulic cylinder is provided with a second rack. The second drive block is provided with a second transmission gear. The outer side wall of the second tooth core is provided with a second drive gear. The second transmission gear is meshed with the second drive gear and the second rack respectively. The second drive block is provided with a second synchronizer. The end of the second tooth core away from the product cavity extends into the second synchronizer and is threadedly connected to the second synchronizer.

10. A demolding method for a plastic part molded by a multi-slider core-pulling injection mold as described in claim 9, characterized in that, Includes the following steps: Mold opening: After the product injection molding is completed in the product cavity, the moving mold is driven to move away from the fixed mold, so that the moving mold and the fixed mold are separated. In the radial core pulling process, as the moving mold moves away from the fixed mold, the moving mold drives the inclined guide post to move synchronously. The inclined guide post drives the push block to slide on the second drive block. The push block pulls the shovel to move synchronously. The shovel drives the third slider to move radially along the second slider, thereby causing the core insert to retract into the second slider. To remove the small thread, the fourth oil cylinder is activated, driving the second rack to move. The second rack drives the second transmission gear meshing with it to rotate, and the second transmission gear drives the second tooth core to rotate synchronously until the second tooth core rotates and extends out of the product cavity. The combined core pulling mechanism activates the third hydraulic cylinder, driving the second drive block to move in the direction of extending out of the product cavity. The second drive block drives the second slider, the radial core pulling assembly, and the second unscrewing assembly to move synchronously until the second slider extends out of the product cavity. On the opposite side, the first hydraulic cylinder is activated, driving the first drive block to move in the direction of extending out of the product cavity. The first drive block drives the first slider to move synchronously until the first slider extends out of the product cavity. To remove the large thread, start the second oil cylinder, drive the first rack to move, the first rack drives the first transmission gear meshing with it to rotate, the first transmission gear drives the first tooth core to rotate synchronously, until the first tooth core rotates and extends out of the product cavity; When the product is ejected, the ejector plate moves, and the ejector plate drives the ejector pins to move synchronously, so that the ejector pins extend into the product cavity and eject the product out of the cavity.

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