Auxiliary mold ejection device for injection product and demolding method

Abstract

The invention relates to an auxiliary mold ejection device for an injection product and a demolding method, and the auxiliary mold ejection device comprises a movable insert pin which is telescopically arranged in a mold core, the front end of the movable insert pin extends into a fixed insert of the mold core, and the fixed insert is used for forming a BOSS column of the injection product; a limiting block is arranged at the rear end of the movable insert pin and located in the containing cavity of the mold core. The spring is arranged on the rear portion of the movable insert pin in a sleeving mode, and the two ends of the spring abut against the limiting block and the front wall of the containing cavity respectively; and the pressing plate is installed at the opening of the containing cavity, and when the BOSS column is not demolded, the pressing plate abuts against the limiting block. Through the application, frequent breakage of the BOSS column when the injection molding product is ejected out can be avoided, and the processing cost is reduced.

Description

Technical Field

[0001] This application relates to the field of mold technology, specifically to an auxiliary ejection device and demolding method for injection molded products. Background Technology

[0002] Injection molding is a widely used manufacturing process. After steps including mold closing, mold locking, injection, pressure holding, cooling, mold opening, and ejection, a finished plastic part is obtained. During the ejection step, the mold ejection mechanism must overcome the clamping force between the molded product and the mold core to separate the product from the mold core for removal. For example... Figure 1-3 As shown, in the injection mold of a license plate frame part, the straight ejector 6 and the angled ejector 7 together provide ejection force, so that the injection molded product 5 and the mold core 4 are separated.

[0003] Assuming the ejection force provided by the injection mold is Fa, the clamping force between the molded product and the mold cavity is Fb, and the actual ejection force applied to the molded product by the ejection mechanism is Fc, based on the relative magnitudes of Fa and Fb, two results will occur: if Fa ≥ Fb, then Fc = Fb; if Fa < Fb, then Fc = Fa, in which case the molded product will not be ejected. In actual injection molding production, it is usually set that Fa > Fb = Fc to ensure that the molded product can be successfully ejected.

[0004] The clamping force between the injection molded product and the mold cavity is mainly determined by the contact area between the injection molded product and the mold core. If the shape of a local area of ​​the injection molded product is complex and the contact area with the mold core is large, a large clamping force will be generated on a relatively small projected area of ​​the injection molded product, and the corresponding ejection force Fc will increase sharply. For example Figure 4 and Figure 5 As shown, compared to partial view b, the area indicated in partial view a has a BOSS pillar 51, which increases the contact area with the mold core 4 by more than 3 times. This results in the ejection force Fca in partial view a being much greater than the ejection force Fcb in partial view b, reaching the stress limit that the BOSS pillar 51 can withstand. Consequently, the BOSS pillar 51 frequently breaks, resulting in a lack of production stability.

[0005] To address the frequent breakage of the BOSS pillar during ejection of injection-molded products, the existing technical solution involves installing ejector pins in the injection mold to eject the BOSS pillar from the injection-molded product. The following explanation uses a license plate bracket part of a certain car model and its injection mold as an example: like Figure 6-9As shown, the ejector sleeve 8 is fixed to the ejector plate 9 by the pressure plate 3 and can perform ejection movement. The pin 10 is fixed to the mold base plate 20 by the pressure plate 3 and cannot move. The ejector sleeve 8 is in direct contact with the end face of the BOSS pillar 51, and the pin 10 is in contact with the inner hole of the BOSS pillar 51. When the mold is opened and ejected, the pin 10 does not move, and the ejector sleeve 8 applies an ejection force to the end face of the BOSS pillar 51, overcoming the clamping force of the outer ring of the BOSS pillar 51 on the mold core 4 and the clamping force of the inner ring on the pin 10, thereby realizing the separation of the BOSS pillar 51 from the mold core 4.

[0006] Although the existing technology has been successfully applied, it has the following two drawbacks: 1. High mold processing cost: The ejector pin structure requires high-precision drilling of the mold core using a deep hole drilling machine, which is costly and necessitates the outsourcing of ejector pins. For example, the installation hole depth of the ejector pin in the core of a bumper injection mold can reach 1080mm, and the positional accuracy of the hole must be within 0.2mm; otherwise, it will lead to sealing failure, jamming during ejector movement, roughening and shedding of iron powder, and other malfunctions.

[0007] 2. Limited usage scenarios: such as Figure 10 As shown, if the BOSS pillar 51 on the injection molded product 5 is ejected using an ejector pin structure, the ejector pin 8 of the ejector pin structure will interfere with the inclined ejector pin 7 of the injection mold, where point e in the figure is the interference area. Therefore, the ejector pin structure cannot be used in this case. Summary of the Invention

[0008] This application provides a mold-assisted ejection device and demolding method for injection molded products, which can prevent frequent breakage of the BOSS pillar when the injection molded product is ejected and reduce processing costs.

[0009] In a first aspect, embodiments of this application provide a mold-assisted ejection device for injection molded products. The mold-assisted ejection device for injection molded products includes: a movable insert pin, which is telescopically disposed within the mold core, and its front end extends into a fixed insert of the mold core, the fixed insert being used to form the BOSS pillar of the injection molded product; a limiting block is provided at the rear end of the movable insert pin, the limiting block being located within the receiving cavity of the mold core; a spring, which is sleeved on the rear part of the movable insert pin, the two ends of the spring respectively abutting against the limiting block (11) and the front wall of the receiving cavity; and a pressure plate, which is installed at the opening of the receiving cavity, the pressure plate abutting against the limiting block when the BOSS pillar is not demolded.

[0010] In conjunction with the first aspect, in some embodiments, the movable insert pin, the mold core, and the fixed insert are all configured to have a zero-clearance fit.

[0011] In conjunction with the first aspect, in some embodiments, the front wall of the receiving cavity is provided with a spring groove, the diameter of the spring groove being smaller than the diameter of the limiting block, and a portion of the spring being located within the spring groove.

[0012] In conjunction with the first aspect, in some embodiments, the rear portion of the mold core has a mounting groove located at and communicating with the rear end of the receiving cavity, and the pressure plate is located within the mounting groove and fixed to the mold core by two mounting members.

[0013] In conjunction with the first aspect, in some embodiments, the front end of the movable insert has a pin that extends into the hole of the BOSS post.

[0014] In conjunction with the first aspect, in some embodiments, a plurality of straight ejectors are also included for ejecting the injection-molded product from the mold core. The plurality of straight ejectors are evenly distributed around the injection-molded product and are telescopically disposed within the mold core. The front end of the straight ejector abuts against the edge of the injection-molded product.

[0015] Secondly, this application provides a demolding method for an auxiliary ejection device for injection molded products based on any of the above embodiments. The demolding method for the auxiliary ejection device for injection molded products includes: during demolding, the BOSS column of the injection molded product drives the movable insert pin to move forward synchronously, and the spring sleeved on the movable insert pin is gradually compressed; when the BOSS column is completely separated from the fixed insert block, the spring's rebound force is greater than the clamping force between the BOSS column and the movable insert pin, and the spring rebounds, causing the movable insert pin to move backward, and the BOSS column disengages from the movable insert pin; the spring continues to rebound until the limit block abuts against the pressure plate.

[0016] In conjunction with the second aspect, in some embodiments, the ejection device further includes a plurality of straight ejectors, which are evenly distributed around the injection molded product and are telescopically disposed within the mold core; during demolding, the straight ejectors eject the injection molded product forward, and the injection molded product first completely separates from the fixed insert, then completely separates from the movable insert, until the injection molded product separates from the mold core.

[0017] In conjunction with the second aspect, in some embodiments, the front wall of the receiving cavity is provided with a spring groove, the diameter of which is smaller than the diameter of the limiting block, and a portion of the spring is located within the spring groove; when the BOSS post is separated from the fixed insert but not from the movable insert, the spring is in a compressed state, and the limiting block abuts against the front wall of the receiving cavity.

[0018] In conjunction with the second aspect, in some embodiments, the front end of the movable insert has a pin that extends into the hole of the BOSS post; during the separation process of the BOSS post from the fixed insert, the pin gradually comes out of the hole of the BOSS post until separation occurs.

[0019] The beneficial effects of the technical solutions provided in the embodiments of the present application include: By telescopically positioning the movable insert within the mold core, with its front end extending into a fixed insert within the mold core—the fixed insert forming the BOSS pillar of the injection-molded product—the system ensures that the front end of the movable insert remains inside the BOSS pillar after injection molding. A limiting block is provided at the rear end of the movable insert, positioned within the receiving cavity of the mold core. When the movable insert extends forward, the limiting block abuts against the front wall of the receiving cavity, restricting further forward movement and preventing the movable insert from detaching from the mold core.

[0020] By placing a spring on the rear of the movable insert, with the two ends of the spring abutting against the limiting block and the front wall of the receiving cavity respectively, when the injection molded product is demolded, the BOSS column exerts a large clamping force on the movable insert, which will simultaneously drive the movable insert to extend forward. At this time, the spring will also gradually compress, and the limiting block will gradually approach the front wall of the receiving cavity until the BOSS column separates from the movable insert. Under the rebound action of the spring, the limiting block is pushed to move backward, thereby resetting the movable insert.

[0021] By installing a pressure plate at the opening of the receiving cavity, when the BOSS pillar is not demolded, the pressure plate abuts against the limiting plate to position the movable insert at its initial position. When the BOSS pillar separates from the movable insert, the pushing limiting block moves backward under the rebound of the spring and abuts against the pressure plate again, which can effectively prevent the movable insert from falling out of the mold core.

[0022] In this embodiment, before demolding, the BOSS pillar is not separated from the fixed insert and the movable pin. Under the action of the spring, the limiting block holds the pressure plate. When the injection molded product is ejected, since the fixed insert is fixed to the mold core, while the movable pin is telescopically positioned on the mold core, the BOSS pillar will initially separate from the fixed insert. During this separation process, the BOSS pillar simultaneously drives the movable pin forward. At this time, the spring is also gradually compressed, and the spring's rebound force gradually increases. When the spring's rebound force is greater than the clamping force between the BOSS pillar and the movable pin, the spring drives the movable pin backward, ultimately allowing the BOSS pillar to detach from the movable pin. Finally, the spring continues to rebound until the limiting block holds the pressure plate, achieving the movable pin's reset action. Therefore, the mold-assisted ejection device for injection molded products of this application can significantly reduce the ejection force required for the BOSS pillar to detach, avoiding the problem of frequent BOSS pillar breakage. At the same time, compared with the existing technology that uses ejector pins, it greatly reduces the mold processing cost and avoids problems such as ejector jamming, scratching, iron powder shedding, bending, and breakage caused by insufficient machining accuracy of deep hole drilling. The manufacturing cost is also relatively low. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a top view of the injection mold for a license plate frame part (i.e., an injection molded product) in the background art; Figure 2 for Figure 1 Cross-sectional view of the injection-molded product in the AA direction before demolding; Figure 3 for Figure 1 Cross-sectional view of the injection-molded product in the center AA direction after demolding; Figure 4 This is a top view of a license plate frame part (i.e., an injection-molded product) in the background art; Figure 5 for Figure 4 A partial sectional view along the BB direction; Figure 6 This is a front view of an injection mold with an ejector pin structure as described in the background art. Figure 7 for Figure 6 A cross-sectional view along the CC direction; Figure 8 for Figure 7 Enlarged view of point c in the middle; Figure 9 for Figure 7 Enlarged view of point d in the middle; Figure 10 for Figure 6 A schematic diagram showing the interference area caused by using a slanted ejector pin in an injection mold. Figure 11 This is a top view of an injection mold with an auxiliary ejection device for injection molded products, as described in an embodiment of this application. Figure 12 for Figure 11 Cross-sectional view along the DD direction (only a portion of the core area is shown); Figure 13 for Figure 12 Enlarged view of point f in the middle; Figure 14 for Figure 12 Enlarged diagram of point g in the middle; Figure 15 This is a flowchart of the demolding method of the mold auxiliary ejection device for injection molded products in the embodiments of this application.

[0025] In the picture: 1. Movable insert pin; 11. Limiting block; 12. Ejector pin; 2. Spring; 3. Pressure plate; 4. Mold core; 41. Fixing insert; 42. Receiving cavity; 43. Spring groove; 44. Mounting groove; 45. Mounting component; 5. Injection molded products; 51. BOSS column; 6. Direct thrust; 7. Sloping roof; 8. Stoker; 9. Ejector plate; 10. Needle; 20. Mold base plate. Detailed Implementation

[0026] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0027] First, some technical terms in this application are explained to facilitate those skilled in the art to understand this application.

[0028] BOSS column: refers to a hollow columnar structure on an injection-molded product used for self-tapping screw fastening. Ribs are typically added around the perimeter of this columnar structure for reinforcement. Ribs are strip-shaped sections added along the main body of the material forming the object, primarily to improve the object's load-bearing capacity and tensile strength. By increasing the thickness of the material at specific locations, the overall strength and durability of the object are enhanced.

[0029] Direct ejection: refers to a structure in injection molds that ejects the product along the mold opening direction, enabling the separation of the injection molded product from the mold core.

[0030] Angled ejector: refers to a structure in injection molds that ejects products. Relative to the mold opening direction, this structure ejects along an inclined direction, enabling the demolding and release of the injection molded product with an undercut structure.

[0031] Sealing: refers to a mold manufacturing method that uses the tight fit between two adjacent parts of an injection mold to prevent molten plastic material from overflowing from the fit point, thus avoiding flash, leakage, and other defects.

[0032] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0033] In one aspect, this application provides a mold-assisted ejection device for injection molded products.

[0034] like Figure 11-14 As shown, in one embodiment, the mold auxiliary ejection device for the injection molded product 5 includes a movable insert pin 1, a spring 2, and a pressure plate 3. The movable insert pin 1 is telescopically disposed within the mold core 4, and its front end extends into the fixed insert 41 of the mold core 4. Figure 13 As shown, the movable insert 1 and the mold core 4 should have a zero-clearance fit. The fixed insert 41 is used to form the BOSS pillar 51 of the injection molded product 5. The fixed insert 41 is a detachable and replaceable mold component used in key parts of the mold core 4 to improve the wear resistance, impact resistance, or achieve special molding functions of the mold core 4. The fixed insert 41 can be made of high-hardness, high-wear-resistant materials, such as cemented carbide or high-speed steel. During the use of the mold core 4, the fixed insert 41 can effectively protect the mold core 4 from damage, extend the service life of the mold core 4, and reduce production costs.

[0035] like Figure 14 As shown, a limiting block 11 is provided at the rear end of the movable insert 1. The limiting block 11 is located within the receiving cavity 42 of the mold core 4. The limiting block 11 can restrict the displacement of the movable insert 1 and prevent it from detaching from the mold core 4. A spring 2 is sleeved on the rear of the movable insert 1, and the two ends of the spring 2 abut against the limiting block 11 and the front wall of the receiving cavity 42, respectively. A pressure plate 3 is installed at the opening of the receiving cavity 42, and the pressure plate 3 can be connected to the mold core 4 through a mounting part 45. When the BOSS pillar 51 is not demolded, the spring 2 can be in a compressed state or a relaxed state. Under the action of the spring 2, the pressure plate 3 abuts against the limiting block 11. The pressure plate 3 and the limiting block 11 can be in planar contact.

[0036] In this embodiment, the movable insert 1 is telescopically positioned within the mold core 4, with its front end extending into the fixed insert 41 of the mold core 4. The fixed insert 41 forms the BOSS pillar 51 of the injection molded product 5. After the injection molded product 5 is formed, it is ensured that the front end of the movable insert 1 is located inside the BOSS pillar 51. By providing a limiting block 11 at the rear end of the movable insert 1 and positioning the limiting block 11 within the receiving cavity 42 of the mold core 4, when the movable insert 1 extends forward, the limiting block 11 abuts against the front wall of the receiving cavity 42, thus restricting the movable insert 1 from continuing to move forward and preventing the movable insert 1 from detaching from the mold core 4.

[0037] By sleeved spring 2 on the rear of movable insert 1, with the two ends of spring 2 abutting against limit block 11 and front wall of receiving cavity 42 respectively, when injection molded product 5 is demolded, due to the large clamping force of BOSS column 51 on movable insert 1, it will synchronously drive movable insert 1 to extend forward. At this time, spring 2 will also gradually compress, and limit block 11 will gradually approach the front wall of receiving cavity 42 until BOSS column 51 separates from movable insert 1. Under the rebound action of spring 2, limit block 11 is pushed to move backward, realizing the reset of movable insert 1.

[0038] By installing the pressure plate 3 at the opening of the receiving cavity 42, when the BOSS pillar 51 is not demolded, the pressure plate 3 abuts against the limiting block 11, positioning the movable insert 1 at its initial position. When the BOSS pillar 51 separates from the movable insert 1, under the rebound action of the spring 2, the pushing limiting block 11 moves backward and abuts against the pressure plate 3 again, effectively preventing the movable insert 1 from falling backward out of the mold core 4.

[0039] In this embodiment, when the BOSS pillar 51 of the injection-molded product 5 is not demolded, the BOSS pillar 51 is not separated from the fixed insert 41 and the movable insert 1. Under the action of the spring 2, the limiting block 11 holds the pressure plate 3. When the injection-molded product 5 is ejected, since the fixed insert 41 is fixed on the mold core 4, and the movable insert 1 is telescopically set on the mold core 4, the BOSS pillar 51 will first separate from the fixed insert 41. During this separation process, the BOSS pillar 51 simultaneously drives the movable insert 1 to move forward. At this time, the spring 2 is also gradually compressed, and the rebound force of the spring 2 will gradually increase. When the rebound force of the spring 2 is greater than the clamping force between the BOSS pillar 51 and the movable insert 1, under the action of the rebound force of the spring 2, the spring 2 drives the movable insert 1 to move backward, finally realizing that the BOSS pillar 51 is separated from the movable insert 1. Finally, the spring 2 continues to rebound until the limiting block 11 holds the pressure plate 3, realizing the reset action of the movable insert 1. Therefore, the mold-assisted ejection device of the injection molded product 5 of this application can significantly reduce the ejection force required when the BOSS pillar 51 detaches, thus avoiding the problem of BOSS pillar 51 breaking. At the same time, compared with the ejector pin technology used in the prior art, it greatly reduces the mold processing cost and avoids problems such as ejector jamming, scratching, iron powder shedding, bending, and breakage caused by insufficient machining accuracy of deep hole drilling. The manufacturing cost is also relatively low.

[0040] Furthermore, in one embodiment, such as Figure 13 As shown, the movable insert 1 is fitted with the mold core 4 and the fixed insert 41 with a zero clearance. In this embodiment, by setting the movable insert 1 and the mold core 4 with a zero clearance fit, jamming of the movable insert 1 during movement can be avoided; by setting the fixed insert 41 and the mold core 4 with a zero clearance fit, sealing can be achieved.

[0041] In other embodiments, such as Figure 13 As shown, the distance from the rear end of the fixed insert 41 to the rear end of the BOSS post 51 is the sealing section. The length of the sealing section should be set between 15mm and 25mm. If it is too long, the movable insert 1 will easily get stuck. If it is too short, the sealing effect will be poor.

[0042] Furthermore, in one embodiment, such as Figure 14 As shown, a spring groove 43 is formed in the front wall of the receiving cavity 42. The diameter of the spring groove 43 is smaller than the diameter of the limiting block 11, and a portion of the spring 2 is located within the spring groove 43. In this embodiment, the spring groove 43 is provided to accommodate the spring 2. By forming a spring groove 43 in the front wall of the receiving cavity 42 and making the diameter of the spring groove 43 smaller than the diameter of the limiting block 11, a portion of the spring 2 is located within the spring groove 43. In this way, the spring 2 can extend and retract along the axial direction of the spring groove 43, which can effectively prevent the rear end of the movable insert 1 from swinging during the extension and retraction of the spring 2, thereby affecting the normal disengagement of the BOSS post 51 and maintaining its stability.

[0043] Furthermore, in one embodiment, such as Figure 14 As shown, the rear of the mold core 4 has a mounting groove 44, which is located at and communicates with the rear end of the receiving cavity 42. The pressure plate 3 is located in the mounting groove 44 and is fixed to the mold core 4 by two mounting members 45. In this embodiment, the diameter of the mounting groove 44 needs to be larger than the diameter of the cavity. By setting the mounting groove 44 at the rear of the mold core 4, the mounting groove 44 is located at the rear end of the receiving cavity 42 and communicates with the receiving cavity 42. The pressure plate 3 is then placed in the mounting groove 44, and the pedal is fixed to the mold core 4 by two mounting members 45. This can lock the movable insert 1 in the receiving cavity 42, preventing the movable insert 1 from being pushed out of the mold core 4 by the spring 2 after the BOSS post 51 separates from the movable insert 1.

[0044] In addition, when assembling the movable insert 1, the movable insert 1 can be first passed through the rear end of the mounting groove 44 and the receiving cavity 42 in sequence and assembled into the mold core 4. Then, the pressure plate 3 is fixed to the mold core 4 by the two mounting parts 45. The disassembly of the movable insert 1 is the exact opposite of the assembly of the movable insert 1, which facilitates the disassembly, assembly and maintenance of the movable insert 1.

[0045] Furthermore, in one embodiment, such as Figure 13As shown, the front end of the movable insert 1 has an ejector pin 12, which extends into the hole of the BOSS pillar 51. In this embodiment, the front end of the movable insert 1 has an ejector pin 12, which is a cylindrical structure aligned with the axis of the movable insert 1. The ejector pin 12 extends into the hole of the BOSS pillar 51, thus ensuring that the BOSS pillar 51 does not break frequently during disengagement. It should be noted that the hole of the BOSS pillar 51 is formed during injection molding.

[0046] In other embodiments, such as Figure 13 As shown, the connection between the rear end of the ejector pin 12 and the front end of the movable insert pin 1 is provided with a C-angle of more than 0.5mm, which can prevent the ejector pin 12 from breaking.

[0047] Furthermore, in one embodiment, such as Figure 12 As shown, the mold-assisted ejection device for the injection-molded product 5 also includes several straight ejectors 6, which are used to eject the injection-molded product 5 and separate it from the mold core 4. The straight ejectors 6 are evenly distributed around the injection-molded product 5 and are telescopically disposed within the mold core 4. The front ends of the straight ejectors 6 abut against the edge of the injection-molded product 5. In this embodiment, the straight ejectors 6 are used to eject the injection-molded product 5, separating it from the mold core 4. By evenly distributing the straight ejectors 6 around the injection-molded product 5 and telescopically distributing them within the mold core 4, with the front ends of the straight ejectors 6 abutting against the edge of the injection-molded product 5, stable demolding of the injection-molded product 5 can be ensured.

[0048] Secondly, this application provides a demolding method for the mold-assisted ejection device of the injection-molded product 5 in any of the above embodiments.

[0049] like Figure 15 As shown, Figure 15 This is a flowchart of a demolding method for an auxiliary ejection device for injection molded products, as described in this application. The demolding method includes: In step S10, during demolding, the BOSS pillar 51 of the injection molded product 5 drives the movable insert 1 to move forward synchronously, and the spring 2 sleeved on the movable insert 1 is gradually compressed.

[0050] In this embodiment, when the injection-molded product 5 is ejected, the fixed insert 41 is fixed to the mold core 4, while the movable pin 1 is telescopically positioned on the mold core 4. Therefore, the BOSS pillar 51 of the injection-molded product 5 will first separate from the fixed insert 41, and the BOSS pillar 51 will drive the movable pin 1 to move forward synchronously. The limiting block 11 and the front wall of the receiving cavity 42 gradually approach each other, while the spring 2 sleeved on the movable pin 1 (located between the limiting block 11 and the front wall of the receiving cavity 42) is gradually compressed, and a rebound force is generated on the limiting block 11. At this time, the ejection force acting on the injection-molded product 5 needs to overcome the combined force of the clamping force generated by the fixed insert 41 on the BOSS pillar 51 and the rebound force generated after the spring 2 is compressed. This can reduce the ejection force required when the BOSS pillar 51 separates from the fixed insert 41.

[0051] In step S20, when the BOSS post 51 is completely separated from the fixed insert 41, the rebound force of the spring 2 is greater than the clamping force between the BOSS post 51 and the movable insert 1. The spring 2 rebounds and drives the movable insert 1 to move backward, and the BOSS post 51 disengages from the movable insert 1.

[0052] In this embodiment, when the BOSS post 51 is completely separated from the fixed insert 41, the ejection force acting on the injection molded product 5 must overcome the combined force of the clamping force between the BOSS post 51 and the movable insert 1 and the rebound force generated after the spring 2 is compressed. The rebound force of the spring 2 is greater than the clamping force between the BOSS post 51 and the movable insert 1. The spring 2 rebounds and drives the movable insert 1 to move backward, and the BOSS post 51 separates from the movable insert 1. By adopting this stepped separation method, the ejection force required for the BOSS post 51 to separate can be significantly reduced, avoiding the problem of frequent breakage of the BOSS post 51. At the same time, compared with the existing technology using ejector pins, the mold processing cost is greatly reduced, and the problems such as ejector jamming, scratching, iron powder shedding, bending, and breakage caused by insufficient deep hole drilling processing accuracy are avoided. The manufacturing cost is also relatively low.

[0053] In step S30, spring 2 continues to rebound until limit block 11 abuts against pressure plate 3.

[0054] In this embodiment, the spring 2 continues to rebound, causing the limiting block 11 to move backward until the limiting block 11 abuts against the pressure plate 3, thereby realizing the quick reset of the movable insert 1, which is convenient for the next injection molding.

[0055] Furthermore, in one embodiment, the ejection device further includes a plurality of straight ejectors 6, which are used to eject the injection molded product 5 from the mold core 4. The plurality of straight ejectors 6 are evenly distributed around the injection molded product 5 and are telescopically disposed inside the mold core 4. The front end of the straight ejector 6 abuts against the edge of the injection molded product 5. During demolding, the straight ejectors 6 eject the injection molded product 5 forward. The injection molded product 5 is first completely separated from the fixed insert 41, and then completely separated from the movable insert 1, until the injection molded product 5 is separated from the mold core 4.

[0056] In this embodiment, through the above technical solution, when the straight ejector 6 pushes the injection molded product 5 forward during demolding, the injection molded product 5 first completely separates from the fixed insert 41, and then completely separates from the movable insert 1, until the injection molded product 5 separates from the mold core 4. This not only provides sufficient ejection force for the demolding of the injection molded product 5, but also ensures the force balance of the injection molded product 5 during demolding, and avoids defects in the injection molded product 5 due to uneven force.

[0057] Furthermore, in one embodiment, a spring groove 43 is provided on the front wall of the receiving cavity 42. The diameter of the spring groove 43 is smaller than the diameter of the limiting block 11, and a portion of the spring 2 is located in the spring groove 43. When the BOSS post 51 is separated from the fixed insert 41 but not separated from the movable insert 1, the spring 2 is in a compressed state, and the limiting block 11 abuts against the front wall of the receiving cavity 42.

[0058] In this embodiment, through the above technical solution, when the injection-molded product 5 is demolded, the spring 2 is partially located within the spring groove 43 until it is completely located within the spring groove 43. The spring groove 43 can, to a certain extent, correct the extension and contraction direction of the spring 2, effectively preventing the spring 2 from bending due to different compression directions. At the same time, the spring groove 43 can also prevent the rear end of the movable insert 1 from vibrating due to the compressed state of the spring 2, thus preventing the movable insert 1 from becoming unstable during the demolding process with the BOSS pillar 51, which could lead to separation failure.

[0059] Furthermore, in one embodiment, the front end of the movable insert 1 has a pin 12, which extends into the hole of the BOSS post 51; during the separation process of the BOSS post 51 from the fixed insert 41, the pin 12 gradually comes out of the hole of the BOSS post 51 until it is separated.

[0060] In this embodiment, through the above technical solution, after the BOSS post 51 separates from the fixed insert 41, as the injection-molded product 5 is gradually ejected, the BOSS post 51 gradually separates from the movable insert 1, and the ejector pin 12 gradually comes out of the hole in the BOSS post 51 until the two are completely separated, thus completing the separation of the BOSS post 51. The ejector pin 12, during the initial separation of the BOSS post 51 from the fixed insert, also transfers the force acting on the BOSS post 51 to the ejector pin 12, avoiding the problem of frequent breakage of the BOSS post 51.

[0061] In the description of this application, it should be noted that the terms "upper" and "lower" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0062] It should be noted that, in this application, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0063] The foregoing is merely a list of specific embodiments of the present application, intended to enable those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the broadest scope consistent with the principles and novel features of the present application.

Claims

1. A mold-assisted ejection device for injection molded products, characterized in that, include: The movable insert (1) is telescopically disposed within the mold core (4), and its front end extends into the fixed insert (41) of the mold core (4). The fixed insert (41) is used to form the BOSS pillar (51) of the injection molded product (5). The rear end of the movable insert (1) is provided with a limiting block (11), which is located in the receiving cavity (42) of the mold core (4). A spring (2) is sleeved on the rear of the movable insert (1), and the two ends of the spring (2) abut against the limiting block (11) and the front wall of the receiving cavity (42) respectively; The pressure plate (3) is installed at the opening of the receiving cavity (42). When the BOSS column (51) is not demolded, the pressure plate (3) abuts against the limiting block (11).

2. The mold auxiliary ejection device for injection molded products as described in claim 1, characterized in that, The movable insert (1) is fitted with the mold core (4) and the fixed insert (41) with zero clearance.

3. The mold auxiliary ejection device for injection molded products as described in claim 1, characterized in that, The front wall of the receiving cavity (42) is provided with a spring groove (43), the diameter of the spring groove (43) is smaller than the diameter of the limiting block (11), and a portion of the spring (2) is located in the spring groove (43).

4. The mold auxiliary ejection device for injection molded products as described in claim 1, characterized in that, The mold core (4) has a mounting groove (44) at the rear. The mounting groove (44) is located at the rear end of the receiving cavity (42) and communicates with it. The pressure plate (3) is located in the mounting groove (44) and is fixed to the mold core (4) by two mounting pieces (45).

5. The mold auxiliary ejection device for injection molded products as described in claim 1, characterized in that, The front end of the movable insert (1) has a pin (12) that extends into the hole of the BOSS post (51).

6. The mold auxiliary ejection device for injection molded products as described in claim 1, characterized in that, It also includes several straight ejectors (6) for ejecting the injection molded product (5) from the mold core (4). The several straight ejectors (6) are evenly distributed around the injection molded product (5) and are telescopically arranged inside the mold core (4). The front end of the straight ejector (6) abuts against the edge of the injection molded product (5).

7. A demolding method based on the mold auxiliary ejection device for injection molded products according to any one of claims 1-6, characterized in that, include: During demolding, the BOSS pillar (51) of the injection molded product (5) drives the movable insert (1) to move forward synchronously, and the spring (2) sleeved on the movable insert (1) is gradually compressed. When the BOSS post (51) is completely separated from the fixed insert (41), the rebound force of the spring (2) is greater than the clamping force between the BOSS post (51) and the movable insert (1). The spring (2) rebounds and drives the movable insert (1) to move backward, and the BOSS post (51) and the movable insert (1) are separated. The spring (2) continues to rebound until the limit block (11) abuts against the pressure plate (3).

8. The demolding method of the mold auxiliary ejection device for injection molded products as described in claim 7, characterized in that, The ejection device also includes a plurality of straight ejectors (6), which are evenly distributed around the injection molded product (5) and are telescopically disposed within the mold core (4); During demolding, the straight ejector (6) pushes the injection molded product (5) forward. The injection molded product (5) first completely separates from the fixed insert (41), and then completely separates from the movable insert (1), until the injection molded product (5) separates from the mold core (4).

9. The demolding method of the mold auxiliary ejection device for injection molded products as described in claim 7, characterized in that, The front wall of the receiving cavity (42) is provided with a spring groove (43), the diameter of the spring groove (43) is smaller than the diameter of the limiting block (11), and a portion of the spring (2) is located in the spring groove (43). When the BOSS post (51) is separated from the fixed insert (41) but not from the movable insert (1), the spring (2) is in a compressed state, and the limiting block (11) abuts against the front wall of the receiving cavity (42).

10. The demolding method of the mold auxiliary ejection device for injection molded products as described in claim 7, characterized in that, The front end of the movable insert (1) has a pin (12) that extends into the hole of the BOSS post (51); During the separation process of the BOSS post (51) from the fixed insert (41), the ejector pin (12) gradually comes out of the hole of the BOSS post (51) until it is separated.

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