A two-stage ejection injection mold

Abstract

The utility model discloses a secondary ejection injection mold, including movable mould bottom plate, thimble bottom plate, thimble faceplate, backing plate and movable template. The both sides of backing plate are fixed with guide seat, and the both sides of thimble bottom plate are fixed with top block, and the both sides recesses of movable template are installed with sliding insert piece, every recess is equipped with spring structure, including sliding sleeve and the compression spring of containing in it, and the inside of sliding insert piece is provided with spring groove, and the sliding sleeve is one -end closed structure, and its open end stretches into spring groove and slides with it, and realizes the guidance through the cooperation of slide rail and sliding slot, and spring structure is used to the outside of sliding insert piece and forms transmission cooperation with top block to be forced to slide in sliding insert piece and separate with top block. The utility model not only can effectively solve the demoulding problem of deep cavity, reverse buckle, slender structure product, and the action is stable and reliable, can effectively prevent the spring of injection molding environment pollution, prolongs the service life of mould, and reduces the maintenance cost of mould.

Description

Technical Field

[0001] This utility model relates to the field of injection molds, specifically a secondary ejection injection mold. Background Technology

[0002] In injection molding, molten plastic is injected into a mold cavity. After cooling and solidifying, the molded plastic product needs to be ejected from the mold; this process is called demolding. The success of demolding directly affects product quality and production efficiency. For some simple plastic products, a single ejection usually meets the demolding requirements. However, with the increasing complexity of plastic product designs, many products with deep cavities, undercuts, side holes, or slender structures often cannot be successfully ejected from the mold in a single ejection. Forced ejection may lead to product deformation and damage, affecting the product's appearance and performance.

[0003] To address these challenges, the industry has developed secondary ejection technology. Secondary ejection mechanisms, through phased and step-by-step ejection actions, can first separate the product from a mold surface with strong adhesion (such as a deep cavity or main core) before completing the subsequent full ejection action, thus significantly improving the demolding success rate of complex products.

[0004] For example, Chinese utility model patent CN216465984U discloses a "secondary ejection mold for slender injection molded parts". This solution utilizes the cooperation between the strip ejector rod and the slider on the secondary ejection assembly. The slider cooperates with the guide seat to make the rear mold plate move together with the ejector plate first, so that the injection molded part separates from the core. When the movement reaches a certain stroke, the guide slope on the guide seat will squeeze the slider, so that the transmission connection between the slider and the strip ejector rod is broken, the rear mold plate stops moving, and the ejector plate continues to move to complete the second ejection, so that the injection molded part is detached from the rear mold core, and the demolding is achieved smoothly.

[0005] However, the aforementioned existing technology still has some shortcomings in practical applications: the elastic connection between the slider and the rear template is key to the slider's movement, but the patent does not disclose the specific implementation structure of this "elastic connection," which is usually achieved using a compression spring. The space where the compression spring is placed is not enclosed, and the spring lacks effective protection and guidance, resulting in poor operational stability. Furthermore, during long-term production operation of the mold, the spring is easily contaminated by dust, oil, and other impurities in the injection molding workshop, affecting its elasticity. This not only reduces the reliability of the entire demolding mechanism but also shortens the mold's lifespan and increases maintenance costs.

[0006] Therefore, how to provide a secondary ejection mechanism with a more reliable structure, more stable operation, and longer service life has become a technical problem that urgently needs to be solved in this field. Utility Model Content

[0007] To address the shortcomings of existing technologies, this utility model provides a secondary ejection injection mold that can not only effectively solve the demolding problem of deep-cavity, undercut, or slender plastic products, but also prevent the spring structure from failing due to contamination of the injection molding environment, extend the service life of the mold, and reduce the frequency and cost of mold maintenance.

[0008] To achieve the above objectives, this utility model provides the following technical solution: A secondary ejection injection mold includes, from bottom to top, a movable mold base plate, an ejector pin base plate, an ejector pin panel, a backing plate, and a movable mold plate. The backing plate is fixedly connected to the movable mold base plate via a pad block. A movable mold core is embedded in the top of the movable mold plate. The ejector pin panel is provided with ejector pins that pass through the backing plate, the movable mold plate, and the movable mold core. A main core extending upward and penetrating the movable mold core is provided on the backing plate. The mold is characterized by further comprising: Two sets of symmetrically arranged guide seats are fixedly connected to both sides of the pad; Two sets of symmetrically arranged top blocks are fixedly connected to both sides of the ejector pin base plate and slidably connected to the inner side of the guide seat. Two sets of symmetrically arranged sliding inserts are installed in grooves opened on both sides of the moving template. The sliding inserts are slidably fitted onto a fixing bolt fixed in the groove. The head of the fixing bolt restricts the sliding inserts to the limit position of sliding outward. Each of the grooves is provided with at least one set of spring structures, each spring structure including a sliding sleeve and a compression spring housed within the sliding sleeve; the inner end of the sliding insert has a spring groove corresponding to the sliding sleeve, the sliding sleeve is a one-end closed structure, its closed end abutting the bottom of the groove, and its open end extending into the spring groove and slidingly engaging with it; one end of the compression spring abuts the closed end of the sliding sleeve, and the other end abuts the bottom of the spring groove; at least one sliding groove is provided on the inner peripheral wall of the spring groove, and a slide rail is provided on the outer peripheral wall of the sliding sleeve to slidely engage with the sliding groove; the spring structure is used to push the sliding insert outward so that it forms a transmission engagement with the top block in its initial position; The inner side of the guide seat is provided with a guide slope for pressing the sliding insert inward. When the top block drives the moving template to move upward to a predetermined stroke through the sliding insert, the guide slope forces the sliding insert to overcome the elastic force of the spring structure and slide inward until it separates from the top block.

[0009] This invention utilizes the cooperation of an ejector block, guide seat, and sliding insert to automatically achieve a secondary ejection action, effectively solving the demolding problem of deep-cavity, undercut, or slender plastic products and avoiding product damage caused by forced demolding. Furthermore, by setting a closed spring structure, a sliding sleeve with one closed end extends into the spring groove of the sliding insert, creating a sealed chamber that expands and contracts with the stroke to accommodate the compression spring. This effectively prevents dust, oil, and other impurities in the injection molding environment from contaminating the spring, solving the problem of exposed springs easily failing in existing technologies. This significantly extends the mold's service life and reduces mold maintenance frequency and costs. Simultaneously, the anti-rotation guide design of the "slide rail and slide groove" between the spring groove and the sliding sleeve prevents spring compression twisting and component rotation, ensuring the smoothness and reliability of the sliding insert's movement during the secondary ejection process, thereby improving the product's molding quality.

[0010] Preferably, the depth of the spring groove is greater than the maximum travel of the sliding insert along the groove. This ensures that the spring remains in a closed, protective state throughout the entire travel of the sliding insert.

[0011] Preferably, the sliding sleeve is a hollow annular sleeve closed at one end. The hollow annular structure better conforms to the spring contour, effectively preventing the spring from twisting or bending, and ensuring stable and smooth slider movement.

[0012] Furthermore, the slide rail is a radial protrusion extending along the sliding direction.

[0013] Preferably, each groove is provided with two sets of spring structures, arranged parallel to each other on the front and rear sides of the fixing bolt. The two sets of symmetrical spring structures provide balanced thrust, preventing the sliding insert from becoming misaligned and stuck.

[0014] Preferably, the sliding insert has a through hole corresponding to the position of the fixing bolt, and a sliding sleeve is provided between the through hole and the fixing bolt. The sliding sleeve reduces sliding friction and further improves the flexibility of the sliding insert's movement.

[0015] Furthermore, the guide seat is provided with a guide groove that runs vertically through the guide seat on the inner side facing the moving template, and a clearance groove that intersects the guide groove perpendicularly. The top block is slidably disposed in the guide groove, and the clearance groove is used to accommodate the sliding insert in the ejected state. The guide slope on the inner side of the guide seat is disposed on the upper wall of the clearance groove.

[0016] Furthermore, the sliding insert has a mating slope at one end facing the guide seat that engages with the guide slope.

[0017] Compared with the prior art, the present invention has the following advantages: 1. A closed spring structure is set up, with a sliding sleeve that is closed at one end extending into the spring groove of the sliding insert to create a sealed chamber that can expand and contract with the stroke to accommodate the compressed spring. With the help of the "slide rail and slide groove" anti-rotation guide design, it not only completely isolates the dust and oil in the injection molding environment, preventing the spring from failing due to contamination, but also significantly extends the service life of the mold, reduces the maintenance frequency and cost of the mold, and eliminates the twisting and component rotation during spring compression, greatly improving the smoothness and reliability of the sliding insert movement. 2. The secondary ejection action is automatically achieved by the cooperation of the ejector block, guide seat and sliding insert. At the same time, relying on the above-mentioned stable and reliable spring structure, the secondary demolding sequence of "moving mold plate first, ejector pin later" can be accurately realized, so that the injection molded part is separated from the core and the rear mold core in sequence. It is especially suitable for plastic products with deep cavity, undercut or slender structure, effectively avoiding product deformation or damage caused by forced demolding and improving product yield. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural diagram of an embodiment of the present utility model.

[0019] Figure 2 This is an exploded structural diagram of an embodiment of the present invention.

[0020] Figure 3 This is a structural schematic diagram of the mold-closed state of an embodiment of this utility model.

[0021] Figure 4 This is a structural schematic diagram of the first ejection state of an embodiment of the present invention.

[0022] Figure 5 This is a structural schematic diagram of the secondary ejection state in an embodiment of this utility model.

[0023] Figure 6 This is a three-dimensional structural diagram of the top block and guide seat in an embodiment of this utility model.

[0024] Figure 7 This is the utility model Figure 7 Disassembly diagram of the assembly of the sliding insert and the spring structure.

[0025] Figure 8 This is a partial cross-sectional view of the spring structure in an embodiment of this utility model.

[0026] In the diagram: 1. Top block; 2. Sliding insert; 21. Fixing bolt; 22. Spring groove; 23. Slide groove; 24. Mating slope; 25. Sliding sleeve; 3. Guide seat; 31. Guide slope; 32. Guide groove; 33. Clearance groove; 4. Moving mold plate; 41. Moving mold core; 42. Groove; 5. Pad plate; 51. Pad block; 6. Ejector pin; 61. Ejector pin panel; 62. Ejector pin base plate; 7. Moving mold base plate; 8. Spring structure; 81. Compression spring; 82. Sliding sleeve; 83. Slide rail; 9. Main core; 100. Injection molded part. Detailed Implementation

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0028] like Figure 1 , Figure 2 and Figure 3 As shown in the figure, this utility model provides a secondary ejection injection mold, which mainly consists of a fixed mold part (not shown) and a moving mold part. The moving mold part includes, from bottom to top, a moving mold base plate 7, an ejector pin base plate 62, an ejector pin panel 61, a backing plate 5, and a moving mold plate 4. The backing plate 5 is supported above the moving mold base plate 7 by pads 51 on both sides, forming an active space for the ejection mechanism. The moving mold plate 4 is installed above the backing plate 5, and a moving mold core 41 is embedded in the top of the moving mold plate 4. A main core 9 extending upward and penetrating the moving mold core 41 is fixed on the backing plate 5. The ejector pin panel 61 and the ejector pin base plate 62 are fixedly connected. The ejector pin 6 is installed on the ejector pin panel 61 and passes upward through the backing plate 5, the moving mold plate 4, and the moving mold core 41 to eject the injection molded part 100.

[0029] Two sets of guide seats 3 are symmetrically fixedly connected to both sides of the pad 5, and two sets of top blocks 1 are fixedly connected to corresponding positions on both sides of the ejector base plate 62. The top blocks 1 are slidably connected to the inner side of the guide seats 3. Specifically, as shown... Figure 6 As shown, the guide seat 3 has a guide groove 32 that runs vertically through the guide seat 3 on the inner side facing the moving template 4, and the top block 1 slides up and down in the guide groove 32.

[0030] like Figure 3 and Figure 7As shown, grooves 42 are symmetrically formed on both sides of the moving template 4, and sliding inserts 2 are installed in the grooves 42. Specifically, a fixing bolt 21 is horizontally fixed in the groove 42, and a through hole is formed on the sliding insert 2 corresponding to the position of the fixing bolt 21. The sliding insert 2 is sleeved on the fixing bolt 21 and can slide along the fixing bolt 21. The head of the fixing bolt 21 acts as a limit, restricting the extreme position of the sliding insert 2 to slide outward. In order to reduce friction, a sliding sleeve 25 is provided between the through hole of the sliding insert 2 and the fixing bolt 21. At least one set of spring structures 8 is provided in each groove 42 to push the sliding insert 2 outward so that it forms a transmission engagement with the top block 1 in the initial position for one push-out.

[0031] like Figure 3 He Ru Figure 6 As shown, the guide seat 3 has an inner side facing the moving template 4 with a clearance groove 33 that perpendicularly intersects the guide groove 32. The clearance groove 33 is used to accommodate the sliding insert 2 in the ejected state. On the inner side of the guide seat 3, specifically at the upper wall of the clearance groove 33, there is an inwardly inclined guide slope 31. Correspondingly, the outer end of the sliding insert 2 facing the guide seat 3 has a mating slope 24 that cooperates with the guide slope 31 (e.g., ...). Figure 7 (As shown). When the ejector block 1 moves the moving template 4 upward to the predetermined stroke via the sliding insert 2, the guide slope 31 forces the sliding insert 2 to overcome the elastic force of the spring structure 8 and slide inward until it separates from the ejector block 1.

[0032] In this embodiment, the spring structures 8 within each groove 42 are preferably in two sets, arranged in parallel on the front and rear sides of the fixing bolt 21. Specifically, as shown... Figure 3 , Figure 7 and Figure 8 As shown, the spring structure 8 includes a sliding sleeve 82 and a compression spring 81 housed within the sliding sleeve. The inner end of the sliding insert 2 (the side facing the bottom of the groove 42) has a spring groove 22 corresponding to the position of the sliding sleeve. The sliding sleeve 82 is a hollow, one-end closed annular sleeve structure, with its closed end abutting against the bottom of the groove 42, and its open end extending into and slidingly engaging with the spring groove 22 of the sliding insert 2. The compression spring 81 is completely enclosed within the telescopic sealed cavity formed by the sliding sleeve 82 and the spring groove 22. One end of the compression spring 81 abuts against the inner wall of the closed end of the sliding sleeve 82, and the other end abuts against the bottom of the spring groove 22. Preferably, the depth of the spring groove 22 is designed to be greater than the maximum travel of the sliding insert 2 along the groove 42. This ensures that even when the sliding insert 2 slides out to its limit position, the sliding sleeve 82 remains partially within the spring groove 22, and the compression spring 81 is never exposed.

[0033] To prevent the spring from twisting or the sleeve from rotating when compressed, such as Figure 7 and Figure 8 As shown, at least one groove 23 is provided axially on the inner peripheral wall of the spring groove 22, and a slide rail 83 that mates with the groove 23 is provided on the outer peripheral wall of the sliding sleeve 82. The slide rail 83 is a radial protrusion extending along the sliding direction. The cooperation between the slide rail 83 and the groove 23 restricts the degree of freedom of the sliding sleeve 82, making it only able to extend and retract smoothly along the axial direction.

[0034] The working process of this utility model is as follows: like Figure 3 As shown, in the mold closing state, under the elastic force of the spring structure 8, the sliding insert 2 is pushed outward to the limit position (initial position). At this time, the outer end of the sliding insert 2 is pushed out into the relief groove 33 of the guide seat 3, and is located above the movement path of the top block 1. That is, the sliding insert 2 and the top surface of the top block 1 are in a transmission engagement state of mutual contact or about to contact. During the first ejection, the injection molding machine ejects, pushing the ejector base plate 62 and ejector plate 61 upward. The ejector base plate 62 drives the ejector block 1 upward along the guide seat 3. The top surface of the ejector block 1 abuts against the bottom surface of the sliding insert 2, thereby pushing the sliding insert 2 and the entire moving mold plate 4 upward together. At this time, the moving mold plate 4 drives the moving mold core 41 and the injection molded part 100 wrapped on it to move upward. The injection molded part 100 separates from the main core 9 on the fixed pad 5, completing the first demolding (e.g., Figure 4 (as shown) During one ejection process, as the moving template 4 moves upward, the mating inclined surface 24 at the outer end of the sliding insert 2 contacts the guiding inclined surface 31 of the relief groove 33. The guiding inclined surface 31 generates an inward pressing force on the sliding insert 2. This force overcomes the elastic force of the spring structure 8, forcing the sliding insert 2 to slide inward along the fixing bolt 21 and retract into the groove 42 until the sliding insert 2 is completely separated from the top surface of the top block 1. At this time, the power connection between the top block 1 and the moving template 4 is disconnected (e.g., Figure 4 (as shown) After the power connection is disconnected, the moving platen 4 stops rising (it can be limited by auxiliary limiting screws, etc., not shown in the figure), and the injection molding machine continues to push the ejector base plate 62 upward, and the ejector block 1 continues to slide upward along the guide groove 32 (at this time, it passes the side of the sliding insert 2 that has been retracted and avoided); at the same time, the ejector pin 6 fixed on the ejector plate 61 continues to move upward relative to the stopped moving platen 4, pushing the injection molded part 100 off the moving mold core 41, completing the second ejection and demolding (as shown in the figure). Figure 5 (as shown) After demolding is completed, the ejection mechanism retracts, the ejector block 1 descends back to its initial position, the sliding insert 2 is no longer subjected to lateral pressure, and under the restoring force of the spring structure 8, it is ejected outward and reset to its initial position, waiting for the next demolding.

[0035] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A secondary ejection injection mold, comprising a movable mold base plate (7), a ejector pin base plate (62), an ejector pin face plate (61), a cushion plate (5) and a movable mold plate (4) arranged in sequence from bottom to top, the cushion plate (5) is fixedly connected with the movable mold base plate (7) through cushion blocks (51), the top of the movable mold plate (4) is embedded with a movable mold core (41), the ejector pin face plate (61) is provided with an ejector pin (6) penetrating through the cushion plate (5), the movable mold plate (4) and the movable mold core (41), the cushion plate (5) is provided with a main core (9) extending upward and penetrating through the movable mold core (41), characterized in that, Also include: Two groups of symmetrically arranged guide seats (3) are fixedly connected on both sides of the backing plate (5); Two groups of symmetrically arranged top blocks (1) are fixedly connected on both sides of the top pin bottom plate (62) and are slidably connected on the inner side of the guide seat (3); Two groups of symmetrically arranged sliding inserts (2) are installed in the grooves (42) opened on both sides of the movable mold plate (4), the sliding insert (2) is slidably sleeved on a fixed bolt (21) fixed in the groove (42), the head of the fixed bolt (21) limits the limit position of the sliding insert (2) sliding outward; At least one spring structure (8) is arranged in each groove, the spring structure (8) includes a sliding sleeve (82) and a compression spring (81) accommodated in the sliding sleeve (82); the inner side end of the sliding insert (2) is provided with a spring groove (22) corresponding to the sliding sleeve (82), the sliding sleeve (82) is a structure with one end closed, the closed end abuts against the groove bottom of the groove (42), the open end extends into the spring groove (22) and slidably cooperates with it; one end of the compression spring (81) abuts against the closed end of the sliding sleeve (82), and the other end abuts against the groove bottom of the spring groove (22); at least one sliding groove (23) is formed in the inner circumferential wall of the spring groove (22), and the outer circumferential wall of the sliding sleeve (82) is provided with a sliding rail (83) slidably cooperating with the sliding groove (23); the spring structure (8) is used for ejecting the sliding insert (2) outward, so that it forms a transmission cooperation with the top block (1) at the initial position; The inner side of the guide seat (3) is provided with a guide slope (31) for inwardly extruding the sliding insert (2), when the top block (1) drives the movable mold plate (4) to move upward to a predetermined stroke through the sliding insert (2), the guide slope (31) forces the sliding insert (2) to slide inward against the elastic force of the spring structure (8), and separates from the top block (1).

2. A secondary ejection injection mold according to claim 1, characterized in that, The depth of the spring groove (22) is greater than the maximum stroke of the sliding insert (2) along the groove (42).

3. A secondary ejection injection mold according to claim 2, characterized in that The sliding sleeve (82) is a hollow and one-end-closed annular sleeve.

4. A secondary ejection injection mold according to claim 2, wherein The sliding rail (83) is a radial protrusion extending in the sliding direction.

5. A secondary ejection injection mold according to claim 1 or 2 or 3 or 4, characterized in that, Two groups of spring structures (8) are arranged in each groove, and are arranged in parallel on the front and rear sides of the fixed bolt (21).

6. A secondary ejection injection mold according to claim 1, characterized in that, A through hole is formed in the sliding insert (2) corresponding to the position of the fixed bolt (21), and a sliding sleeve (25) is arranged between the through hole and the fixed bolt (21).

7. A secondary ejection injection mold according to claim 1, characterized in that, The inner side of the guide seat (3) towards the movable mold plate (4) is provided with a guide groove (32) penetrating through the guide seat (3) and a avoiding groove (33) vertically intersecting with the guide groove (32), the top block (1) is slidably arranged in the guide groove (32), the avoiding groove (33) is used for accommodating the sliding insert (2) in the ejecting state, and the guide slope (31) on the inner side of the guide seat (3) is arranged on the groove wall of the avoiding groove (33).

8. A secondary ejection injection mold according to claim 7, characterized in that One end of the sliding insert (2) is provided with a matching inclined surface (24) matched with the guide inclined surface (31).

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