Structure for firstly ejecting central nozzle needle of injection mold
By setting a combined structure of a water outlet needle and a return spring in the center of the mold, the water outlet needle of the injection mold is ejected first, which solves the problem of high cost in the prior art, and achieves a low-cost and efficient mold modification effect, avoiding the phenomenon of concave at the gate.
Patent Information
- Application Number
- CN202422294720.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-20
- Publication Date
- 2025-07-11
- Estimated Expiration
- 2034-09-20
AI Technical Summary
In the existing mold design, the cost of using a delayed thimble or a double thimble plate when the center water outlet needle is ejected first is higher, and the cost is significantly increased in the case of multiple cavity and multiple gates, especially the cost of modification after the mold has been processed is higher.
The water outlet needle is set up in the center of the mold. The bottom of the water outlet needle is higher than the bottom plate of the thimble. It is equipped with a return spring. The injection molding machine top stick first contacts the bottom of the water outlet needle, so that it ejects first, and restores the original state through the return spring to avoid the increase in the double thimble plate structure.
It reduces the cost and construction period of mold modification, avoids the problem of concave at the gate of plastic products, and has a simple structure and low cost.
Smart Images
Figure CN223085336U_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of ejection structures for injection molds, and particularly to a structure for ejecting a central sprue pin of an injection mold first. Background Art
[0002] In an injection mold, a submarine gate or a horn gate sometimes needs to separate the runner and the product for ejection due to various reasons. Usually, the method is to add delay ejector pins under all the ejector pins on the product or to make a double ejector pin plate, and install the runner ejector pin and the product ejector pin separately.
[0003] In the case where the runner needs to be ejected first, adding delay ejector pins can only be selected when the number of product ejector pins is small. On the contrary, when there is one runner ejector pin and hundreds of product ejector pins, it is costly to make delays for hundreds of product ejector pins in order to eject one runner ejector pin first; making a double ejector pin plate requires increasing the height of the mold feet and the lengths of all the accessories on the ejector pin plate, and also making an additional set of ejector pin plates and a mechanism for controlling the opening distance of the two sets of ejector pin plates. This structure is more reasonable in the case of multiple cavities and multiple gates, but the cost is obviously high when there is only one runner ejector pin. Especially when starting the design, the mold designer did not design the runner first ejection structure. After the trial mold, it was found that when the gate was pulled off, the surface of the product was concave. It was necessary to add a runner first ejection structure later to improve the situation. At this time, making a double ejector pin plate structure requires adding two more ejector pin plates, and the height of the mold feet of the mold base and the lengths of all the accessories on the ejector pin plate need to be lengthened. However, since the mold has been processed, the mold feet and the accessories on the ejector pin plate can only be scrapped and remade, resulting in even higher costs. Summary of the Invention
[0004] In order to solve the problem of high costs when using delay ejector pins or double ejector pin plates for the first ejection of the central sprue pin of an existing mold, the present invention provides a structure for the first ejection of the central sprue pin of an injection mold. The sprue pin is arranged at the center of the mold, and the bottom of the sprue pin is higher than the ejector pin bottom plate of the injection mold by a certain distance, that is, the distance to be ejected first. A return spring is installed on the sprue pin for resetting. When the injection molding machine ejector rod moves upward, it will first contact the bottom of the sprue pin. When the injection molding machine ejector rod retracts, under the action of the return spring, the sprue pin will retract together until it is reset, achieving the effects of reducing costs and shortening the construction period, and there is no longer a problem of concave pulling at the gate of the ejected plastic product.
[0005] The technical solution adopted by the present invention is as follows: A structure for the prior ejection of the central sprue pin of an injection mold, including a moving mold core, a moving mold frame, an ejector plate, an ejector bottom plate, a mold base bottom plate, and an injection molding machine ejector rod, further including a sprue pin, a return spring, and a retaining ring; the short end of the sprue pin is arranged in the ejector pin counterbore II of the ejector bottom plate, and the short end of the sprue pin extends out of the ejector pin counterbore II and corresponds to the injection molding machine ejector rod in the mold base bottom plate. The long end of the sprue pin sequentially passes through the counterbore of the ejector plate and the through hole I of the moving mold frame and is placed in the through hole II of the moving mold core. The retaining ring and the return spring are sequentially sleeved on the long end of the sprue pin. The retaining ring is arranged on the shoulder of the sprue pin. One end of the return spring is arranged on the retaining ring, and the other end of the return spring passes through the counterbore of the ejector plate and is in contact and cooperation with the outer peripheral surface of the through hole I of the moving mold frame;
[0006] When the injection molding machine ejector rod moves upward, it drives the long end of the sprue pin to move upward in the through hole II of the moving mold core, and the return spring is in a compressed state. When the injection molding machine ejector rod moves downward, the return spring extends, causing the sprue pin to return to its original state.
[0007] The beneficial effects produced by the present invention are as follows: 1. The plastic products ejected using this structure no longer have the problem of concave drawing at the gate. 2. Among the parts that need to be modified in the mold, only the ejector plate and the ejector bottom plate of the mold base are required. An additional central counterbore needs to be added to the ejector plate, and an additional ejector pin counterbore needs to be added to the ejector bottom plate. Whether the mold designer designs first or makes design changes after trial molding, the cost is not high. Compared with making delayed ejector pins and double ejector plates, the cost is greatly reduced, and the processing cycle is also greatly shortened. Description of the Drawings
[0008] Figure 1 is a schematic structural diagram of the present invention;
[0009] Figure 2 is a schematic structural diagram of the moving mold core of the present invention;
[0010] Figure 3 is a schematic structural diagram of the moving mold frame of the present invention;
[0011] Figure 4 is Figure 3 a cross-sectional view of the structure;
[0012] Figure 5 is a schematic structural diagram of the ejector plate of the present invention;
[0013] Figure 6 is Figure 5 a cross-sectional view of the structure;
[0014] Figure 7 is a schematic structural diagram of the ejector bottom plate of the present invention;
[0015] Figure 8 is Figure 7 a cross-sectional view of the structure;
[0016] Figure 9 It is a structural schematic diagram of the mold base plate of the present invention;
[0017] Figure 10 for Figure 9 Cross-sectional view of the structure;
[0018] Figure 11 It is a structural schematic diagram of the nozzle needle of the present invention;
[0019] Figure 12 A schematic diagram of the structure of an injection molding machine completing the injection of two plastic products;
[0020] Figure 13 It is a side view of the plastic product structure.
[0021] In the figure: 1. movable mold core; 1-1. through hole II; 1-2. ejector hole II; 1-3. bullhorn tunnel; 2. movable mold frame; 2-1. groove; 2-2 through hole I; 2-3. ejector hole I; 2-4. blind hole; 2-5. reset rod countersunk hole II; 3. ejector plate; 3-1. center countersunk hole; 3-2 ejector countersunk hole I; 3-3. reset rod countersunk hole I; 3-4. ejector plate guide post through hole I; 4. ejector bottom plate; 4-1. ejector Countersink II; 4-2. Ejector plate guide pin through hole II; 5. Mold base plate; 5-1. Ejector rod countersink; 5-2. Countersink; 6. Gate needle; 7. Reset spring; 8. Retaining ring; 9. Injection molding machine ejector; 10. Mold foot I; 11. Ejector plate guide pin; 12. Reset rod; 13. Ejector plate reset spring; 14. Product ejector; 15. Mold foot II; 16. Plastic product; 16-1. Bull horn gate; 16-2. The thinnest part of the product. DETAILED DESCRIPTION
[0022] The present invention will be further described below in conjunction with the accompanying drawings.
[0023] like Figures 1 to 11 As shown, a structure for ejecting the center sprue needle of an injection mold first comprises a movable mold core 1, a movable mold frame 2, an ejector plate 3, an ejector base plate 4, a mold frame base plate 5, a sprue needle 6, a reset spring 7, a retaining ring 8, an injection molding machine ejector rod 9, a mold foot I 10, an ejector plate guide column 11, a reset rod 12, an ejector plate reset spring 13, a product ejector 14 and a mold foot II 15.
[0024] Insert multiple product ejector pins 14 into multiple ejector pin countersunk holes Ⅰ3-2 on both sides of the central countersunk hole 3-1 of the ejector plate 3, insert four reset rods 12 into four reset rod countersunk holes Ⅰ3-3 of the ejector plate 3, and set an ejector plate reset spring 13 on each reset rod 12, with one end of the reset spring 13 placed on the ejector plate 3;
[0025] The long end of the sprue pin 6 passes through the retaining ring 8 and extends outside the central counterbore 3-1 of the ejector plate 3. The retaining ring 8 on the round shoulder 6-1 of the sprue pin 6 is arranged inside the central counterbore 3-1. The return spring 7 is sleeved on the long end of the sprue pin 6, and one end of the return spring 7 is placed on the retaining ring 8.
[0026] The ejector plate bottom plate 4 is arranged under the ejector plate 3, and the ejector plate 3 and the ejector plate bottom plate 4 are fixed together by screws. At this time, the short end of the sprue pin 6 is arranged in the ejector pin counterbore II 4-1 of the ejector plate bottom plate 4, and the short end head of the sprue pin 6 extends outside the ejector pin counterbore II 4-1.
[0027] Two mold feet I 10 and two mold feet II 15 are symmetrically fixed on both sides of the upper surface of the mold base bottom plate 5. The fixed ejector plate 3 and ejector plate bottom plate 4 are arranged on the mold base bottom plate 5 between the two mold feet I 10 and the two mold feet II 15. The short end head of the sprue pin 6 extending outside the ejector pin counterbore II 4-1 corresponds to the injection molding machine ejector rod 9 in the ejector rod counterbore 5-1 of the mold base bottom plate 5. The moving mold core 1 is fixed in the groove 2-1 of the moving mold frame 2 by a plurality of screws, and the moving mold frame 2 is fixed on the two mold feet I 10 and the two mold feet II 15.
[0028] At this time, the long end of the sprue pin 6 passes through the through hole I 2-2 of the moving mold frame 2 and is placed in the through hole II 1-1 of the moving mold core 1. The other end of the return spring 7 is placed outside the through hole I 2-2 of the moving mold frame 2. The upper ends of a plurality of product ejector pins 14 respectively pass through a plurality of ejector pin holes I 2-3 of the moving mold frame 2 and are correspondingly inserted into a plurality of ejector pin holes II 1-2 of the moving mold core 1. The upper ends of the four return rods 12 are respectively placed in the four return rod counterbores II 2-5 of the moving mold frame 2, and the other ends of the four return springs 13 are respectively placed at the bottom of the large diameter holes in the four return rod counterbores II 2-5.
[0029] The four ejector plate guide posts 11 are fixed in the four counterbores 5-2 of the mold base bottom plate 5. The upper ends of the four ejector plate guide posts 11 respectively pass through the four ejector plate guide post through holes I 3-4 of the ejector plate 3 and the four ejector plate guide post through holes II 4-2 of the ejector plate bottom plate 4 and are screwed together with the four threaded blind holes 2-4 of the moving mold frame 2.
[0030] A round shoulder 6-1 is provided in the middle of the sprue pin 6. The upper end of the round shoulder 6-1 is the long end, and the lower end of the round shoulder 6-1 is the short end. The sprue pin 6 is the main part of this structure. The main function is that the short end can extend a certain distance from the bottom surface of the ejector plate bottom plate 4 and contact the injection molding machine ejector rod 9 first. Since all the product ejector pins 14 are installed on the ejector plate 3, when the injection molding machine ejector rod 9 pushes the sprue pin 6, it has not yet contacted the ejector plate bottom plate 4, so the sprue pin 6 is pushed out first, while the product ejector pins 14 remain stationary. The existing ordinary ejector pins need to be installed in a hanging platform-to-hanging platform manner with one long and one short ejector pin to achieve this function. The structure of the sprue pin 6 is mainly to save space at the hanging platform.
[0031] The main function of the return spring 7 is to reset the sprue pin 6.
[0032] The diameter of the retaining ring 8 is larger than the diameter of the round shoulder 6-1 of the sprue pin 6. The main function of the retaining ring 8 is to prevent the sprue pin 6 from not reaching the proper position during reset when the return spring 7 on the sprue pin 6 is fatigued, thus preventing the sprue pin 6 from separating from the ejector plate 3.
[0033] Under the compression or extension of multiple ejector plate return springs 13, the ejector plate 3 and the bottom ejector plate 4 can move up and down under the guiding action of the ejector plate guide posts 11.
[0034] The combination of the sprue pin 6, the return spring 7 and the retaining ring 8 can achieve the effect that a sprue pin in the center of the mold ejects first at a lower cost. The conventional method is to delay the product ejector pin or use a double-layer ejector plate, which has a higher cost and a longer cycle.
[0035] Example, such as Figure 12 and Figure 13 As shown, a method for realizing the structure of the center sprue pin of an injection mold ejecting first. First, fix this injection mold on the injection machine template through the mold base bottom plate 5. The injection machine completes the injection, pressure holding, cooling and other processes for two plastic products 16;
[0036] The ejector rod 9 of the injection machine starts to move upward under the drive of the injection machine oil cylinder. Since the short end of the sprue pin 6 is higher than the bottom surface of the bottom ejector plate 4 by a certain distance S, the ejector rod 9 of the injection machine will first contact the short end of the sprue pin 6. After the ejector rod 9 of the injection machine contacts the short end of the sprue pin 6, the sprue pin 6 starts to be ejected upward first. At this time, the center of the horn gate 16-1 connecting the two plastic products 16 is also ejected by a certain distance. Under the ejection action of the sprue pin 6, the middle of the horn gate 16-1 starts to bend. Under the action of the tensile force, the horn gate 16-1 will be pulled open by a certain distance along the horn tunnel 1-3, so that the thinnest part 16-2 of the product where the horn gate 16-1 is connected to the two non-ejected plastic products 16 is first broken. At this time, the return spring 7 is in a compressed state; since the two plastic products 16 are wrapped around the mold core 1 at this time, there is support around the gate when the horn gate 16-1 is broken, so the surface of the product will not be pulled concave;
[0037] The first ejection action of the sprue pin 6 ends. The ejector rod 9 of the injection machine starts to contact the bottom of the bottom ejector plate 4. The sprue pin 6 and multiple product ejector pins 14 are ejected together until the two plastic products 16 and the horn gate 16-1 are all ejected out of the movable mold core 1 and the ejection action ends. At this time, multiple return springs 13 are in a compressed state;
[0038] Since the horn gate 16-1 is pulled off in advance, there is no problem of the pulled concave at the gate on the plastic product 16 ejected at this time;
[0039] Subsequently, the ejector rod 9 of the injection molding machine moves downward under the drive of the injection molding machine cylinder. The stretching action of multiple return springs 13 causes the ejector plate 3, the ejector bottom plate 4 and multiple product ejector pins 14 fixed together to reset under the guidance of multiple return rods 12 and multiple ejector plate guide columns 11, returning to the original state. At the same time, the sprue pin 6 resets under the action of the return spring 7 and returns to the original state. The present invention is applicable to all horn gate or submarine gate injection molds with a single-point ejection at the center of the mold.
[0040] When designing the present invention, it is necessary to first calculate the ejection distance S to be ejected first and the compression ratio of the spring 7. The ejection distance S for the short end of the sprue pin 6 to extend out of the ejector bottom plate 4 is 10 mm - 15 mm, and the spring 7 is in a pre-compressed state. The clearance distance S1 between the retaining ring 8 and the bottom of the large-diameter hole in the counterbore 3-1 of the ejector plate 3 is S + 0.5 mm.
Claims
1. A structure for the prior ejection of the central sprue pin of an injection mold, comprising a moving die core (1), a moving die frame (2), an ejector plate (3), an ejector plate base (4), a mold base bottom plate (5), and an injection molding machine ejector rod (9), characterized in that, It further includes a sprue pin (6), a return spring (7) and a retaining ring (8); the short end of the sprue pin (6) is arranged in the ejector pin counterbore II (4-1) of the ejector pin bottom plate (4), and the short end head of the sprue pin (6) extends out of the ejector pin counterbore II (4-1) and corresponds to the injection molding machine ejector rod (9) in the mold base bottom plate (5). The long end of the sprue pin (6) sequentially passes through the counterbore (3-1) of the ejector pin plate (3) and the through hole I (2-2) of the moving die frame (2) and is placed in the through hole II (1-1) of the moving die insert (1). The retaining ring (8) and the return spring (7) are sequentially sleeved on the long end of the sprue pin (6). The retaining ring (8) is arranged on the round shoulder (6-1) of the sprue pin (6). One end of the return spring (7) is arranged on the retaining ring (8), and the other end of the return spring (7) passes through the counterbore (3-1) of the ejector pin plate (3) and is in contact and cooperation with the outer peripheral surface of the through hole I (2-2) of the moving die frame (2). When the injection molding machine ejector rod (9) moves upward, it drives the long end of the sprue pin (6) to move upward in the through hole II (1-1) of the moving die insert (1), and the return spring (7) is in a compressed state. When the injection molding machine ejector rod (9) moves downward, the return spring (7) expands to make the sprue pin (6) return to its original state.
2. The structure of the center gate needle of an injection mold that first ejects as claimed in claim 1, characterized in that The middle part of the sprue pin (6) is provided with a round shoulder (6-1). The upper end of the round shoulder (6-1) is the long end, and the lower end of the round shoulder (6-1) is the short end.
3. The structure of the center sprue needle of an injection mold that first ejects as claimed in claim 1, wherein, The distance S from the short end head to the bottom surface of the ejector pin bottom plate (4) is 10 mm - 15 mm, and the clearance distance S1 between the retaining ring (8) and the bottom of the large-diameter hole in the counterbore (3-1) of the ejector pin plate (3) is S + 0.5 mm.