Injection moulding lower mould with exhaust and anti-sticking ejection mechanism

Abstract

This utility model discloses an injection mold lower mold with a venting and anti-sticking ejection mechanism, relating to the field of injection mold technology. It includes a fixed base plate, a lifting ejection mechanism, and a fixed lower mold. The core mold is equipped with a stacked, sheet-like venting mechanism. Multiple venting plates combine to form a dense venting channel, quickly expelling trapped air from the mold cavity and eliminating air marks and weld lines on the product. The lifting plate, translation slide, guide slider, inclined support rod, and main push rod constitute a coordinated ejection structure. During demolding, the core mold limits the injection molded workpiece by inverting and flipping the edge to prevent sticking and deformation. The inclined support rod provides stable guidance, reducing wear and jamming. The venting mechanism is easy to disassemble and assemble; the blocking venting plate can be replaced individually without modifying the product or gate. It is compatible with various automotive injection molded parts with inverted edges, broadening the process window, improving yield, and reducing mold maintenance time.

Description

Technical Field

[0001] This utility model relates to the field of injection mold technology, specifically to an injection mold with a venting and anti-sticking ejection mechanism. Background Technology

[0002] During the molding process of injection molding products through injection molding machines and injection molds, the product structure, gate layout, and melt flow can easily cause trapped air inside the mold cavity. If the air cannot be discharged smoothly, it will form appearance defects such as air marks and weld lines on the product surface. At the same time, when automotive injection molded parts with undercut and flange structures are demolded, the undercut and flange of the product are prone to move with the angled ejector during the lateral release process, resulting in problems such as sticking to the mold, product damage, and ejection jamming.

[0003] The current industry mainstream solutions for handling air entrapment defects fall into three categories: 1. Reduce the melt filling speed and rely on the parting surface to slowly vent air; this solution is greatly affected by the fluctuation of plastic raw material flowability, has a weak effect on improving the air trapped in the encapsulated type, and has poor production stability. 2. Modify product wall thickness and adjust gate position to avoid air entrapment; changes to product wall thickness require customer confirmation, which can easily reduce product structural strength, and gate changes are costly and have poor adaptability; 3. Simple venting grooves are opened on the side wall of conventional inserts; the venting capacity is limited, and in most working conditions it still needs to be used in conjunction with the speed reduction process, which cannot completely eliminate the air mark defect.

[0004] To address the issue of product sticking to the mold during demolding after undercutting, traditional angled ejectors rely solely on the angled ejector rod and angled ejector slide to achieve lateral demolding without any auxiliary limiting structure. During ejection, the undercutting edge of the product is unrestrained and easily moves backward with the angled ejector, causing scratches and deformation to the product. Furthermore, the angled ejector mechanism may experience jamming, rapid wear, and short service life due to long-term unilateral force.

[0005] In summary, existing mold structures cannot simultaneously achieve efficient venting and stable anti-sticking ejection with undercuts, resulting in low production yield, frequent mold maintenance, and a narrow range of process adjustability. There is an urgent need for an injection molding lower mold structure that integrates efficient venting and undercut anti-sticking ejection. Utility Model Content

[0006] This utility model aims to solve at least one of the technical problems existing in the prior art. To this end, one objective of this utility model is to propose an injection mold with a venting and anti-sticking ejection mechanism, which integrates a sheet-like stacked venting insert and multiple sets of coordinated ejection and release structures to simultaneously achieve efficient venting of the mold cavity, anti-sticking positioning of the product with undercuts, stable guidance of the inclined ejector, widening the injection molding process window, reducing the product scrap rate, and simplifying mold disassembly and maintenance.

[0007] To achieve the above objectives, this utility model provides an injection mold with a venting and anti-sticking ejection mechanism. The injection mold and the upper injection mold together form an injection processing area. The injection mold includes a fixed base plate, a lifting ejection mechanism, and a fixed lower mold. The lifting ejection mechanism is fixedly provided with a venting mechanism that connects the inside and outside of the injection processing area. The lifting ejection mechanism is connected to the lifting base plate by a lifting guide, and the fixed lower mold is fixedly supported above the fixed base plate. The lifting ejection mechanism and the fixed lower mold cooperate with the upper injection mold to form the injection processing area.

[0008] Preferably, multiple vertical support rods are vertically fixed to the four corners of the fixed base plate, and the middle section of the vertical support rod is equipped with a lifting and ejection mechanism, and the top of the vertical support rod is fixed to the lower mold.

[0009] Preferably, the lifting and ejecting mechanism includes a lifting plate, a translation slide, an inclined support rod, a main push rod, a guide slider, and a core mold; The lifting plate is mounted on a vertical support rod, and multiple translation slide blocks are fixed on the top surface of the lifting plate. The vertically limited and laterally sliding support guide slider is located on the translation slide block; The guide slider is fixed at the bottom of the main push rod, and the middle part of the guide slider is slidably fitted onto the inclined support rod; The upper part of the main push rod slides axially through the fixed lower mold, and the top of the main push rod is fixedly supporting the core mold; The core mold is equipped with an exhaust mechanism, and the core mold slides down and overlaps the top surface of the fixed lower mold.

[0010] Preferably, the lifting plate has a vertical through-hole in the middle; the top of the inclined support rod is fixed to the bottom surface of the fixed lower mold, the middle section of the inclined support rod penetrates the through-hole, and the bottom end of the inclined support rod is fixed to the top surface of the fixed base plate.

[0011] Preferably, a horizontally extending guide groove is provided on the side wall of the translation slide block; the main push rod is inclinedly supported on the guide slider, and horizontally arranged wing plates are fixed on both sides of the guide slider; the horizontal wing plates are slidably inserted into the horizontal guide groove, and are vertically constrained and horizontally slidably connected inside the horizontal guide groove.

[0012] Preferably, a gap for injection molding is left between the edge of the core mold and the top surface of the fixed lower mold.

[0013] Preferably, the venting mechanism includes a venting groove, a venting box, and multiple venting plates; the venting groove is formed on the injection molding working surface of the core mold, the venting box is fixedly connected to the venting groove with bolts, and the venting groove is in communication with the gas inside and outside the injection molding processing area.

[0014] Preferably, the exhaust box has a vertical through slot in the middle, and multiple exhaust plates are inserted into the slot in a gap fit and in parallel arrangement.

[0015] Preferably, multiple pins are horizontally inserted and fixed to the exhaust box, and the pins fix the exhaust plate inside the slot.

[0016] The advantages of this utility model compared with the prior art are as follows: 1. This utility model designs an integrated sheet-like superimposed venting mechanism. Multiple venting plates are combined to form a dense shallow venting channel. Trapped air wrapped in molten adhesive can be quickly discharged from the mold cavity through the gaps between the venting plates, thoroughly improving product defects such as air marks and weld lines. The gaps between the venting plates are of uniform specifications, allowing for a wider range of adjustable injection molding process parameters. The impact of raw material flow fluctuations on molding quality is significantly reduced, and the product qualification rate is significantly improved.

[0017] 2. This utility model designs a collaborative undercut anti-stick ejection structure for the core mold and the fixed lower mold: it works with the guide slider to provide stable guidance for the inclined ejector and reduce the wear and tear of the inclined ejector; when the core mold ejects, it makes room for the inclined ejector to disengage laterally; when the inclined ejector retracts and disengages, the undercut of the bottom edge of the injection molded workpiece is positioned to prevent the product from shifting, bumping and deforming with the inclined ejector, thus solving the problem of undercut products sticking to the mold.

[0018] 3. The venting mechanism is easy to disassemble and maintain. It can be flexibly designed and installed on the mold according to the shape of the injection molded workpiece and the location where gas is easy to accumulate. The venting plate is locked in the venting box by the pin. The whole can be detached and installed in the venting groove of the core mold by the internal hex bolts. After long-term use, only the bolts need to be removed and the pin pulled out to replace the worn and blocked venting plate. There is no need to disassemble the entire ejection structure, which greatly shortens the mold maintenance time.

[0019] 4. It has strong structural versatility. Through mold flow analysis and early mold trial to locate the location of air trapping defects, this venting mechanism can be installed at any core mold without modifying the product wall thickness or adjusting the gate. It is compatible with various automotive injection molds with flanges and undercuts, and the modification cost is low. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the 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.

[0021] Figure 1 This is a three-dimensional structural diagram of the present invention (with the hidden part fixed to the lower mold); Figure 2 This is a three-dimensional structural diagram showing the parallel relationship between the main push rod and the inclined support rod in this utility model (the hidden part is fixed to the lower mold). Figure 3 for Figure 1A magnified view of a section at point A (showing the vertical constraint and horizontal sliding connection between the translation slide and the guide slider). Figure 4 This is a cross-sectional view of the present invention; Figure 5 This is a cross-sectional view of the injection mold lower mold with the injection molded workpiece of this utility model (showing that the bottom bend of the injection molded workpiece is surrounded by the core mold and the fixed lower mold, and that the bend is easy to demold as the core mold rises). Figure 6 This is a three-dimensional exploded view of the exhaust mechanism in this utility model; Figure 7 This is a three-dimensional structural diagram of the injection-molded workpiece after processing according to this utility model; In the diagram: 1-Fixed lower mold; 2-Core mold; 3-Exhaust mechanism; 4-Angled support rod; 5-Vertical support rod; 6-Lifting plate; 7-Fixed base plate; 8-Transfer slide; 9-Guide slider; 10-Main push rod; 11-Horizontal guide groove; 12-Horizontal wing plate; 13-Exhaust plate; 14-Leaning opening; 15-Injection molded part; 16-Exhaust groove; 17-Exhaust box; 18-Groove opening; 19-Pin rod. Detailed Implementation

[0022] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0023] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0024] The present invention will now be described in further detail with reference to the accompanying drawings.

[0025] This utility model provides an injection mold with a venting and anti-sticking ejection mechanism. The injection mold used in conjunction with it is a mature product in the prior art. The injection processing area is formed by the injection mold and the injection mold together. The injection mold is composed of three main parts: a fixed base plate 7, a lifting ejection mechanism, and a fixed lower mold 1. Vertical support rods 5 are mounted vertically at the four corners of the fixed base plate 7. The lifting ejection mechanism is slidably sleeved in the middle of the vertical support rods 5. The top of the vertical support rods 5 provides fixed support for the fixed lower mold 1. The lifting ejection mechanism, the fixed lower mold 1 and the upper mold cooperate to complete the injection molding.

[0026] The core of the lifting ejection mechanism is the lifting plate 6, which can slide up and down along the vertical support rod 5. Multiple sets of translation slides 8 are fixed on the top surface of the lifting plate 6, and horizontal guide grooves 11 are opened on the side walls of the translation slides 8. Horizontal wing plates 12 extend from both sides of the guide slider 9 and are inserted into the horizontal guide grooves 11 to realize the vertical limitation and horizontal free sliding of the guide slider 9. An inclined support rod 4 is installed in the middle of the guide slider 9. The upper and lower ends of the inclined support rod 4 are respectively connected to the bottom surface of the fixed lower mold 1 and the top surface of the fixed base plate 7. A clearance opening 14 is opened in the middle of the lifting plate 6 for the inclined support rod 4 to pass through. During the lifting process of the lifting plate 6, the inclined support rod 4 remains fixed and drives the guide slider 9 to move horizontally. The horizontal wing plates 12 slide horizontally inside the horizontal guide grooves 11 to avoid structural self-locking between the main push rod 10 and the lifting plate 6 during the lifting process.

[0027] A main push rod 10 is fixed above the guide slider 9. The main push rod 10 penetrates the fixed lower mold 1 upwards, and a core mold 2 is assembled at its top. A forming gap is reserved between the core mold 2 and the fixed lower mold 1 for forming the undercut structure at the bottom of the workpiece. The lifting plate 6 is synchronously slidably assembled with a vertical support rod 5. The vertical support rod 5 extends upwards through the fixed lower mold 1 to form a vertical fixed support, which is arranged corresponding to the undercut area of ​​the workpiece. A diagonal support rod 4 is set parallel to the main push rod 10 to ensure the slope of the main push rod 10. This slope will directly affect the upward tilt angle of the core mold 2 when it leaves the fixed lower mold 1. The diagonal support rod 4 is fixed between the fixed base plate 7 and the fixed lower mold 1 to guide the movement of the main push rod 10, reduce ejection jamming, and reduce wear of the diagonal ejector rod.

[0028] The core mold 2 has an venting groove 16 on its injection working surface. The bottom of the venting groove 16 has a through venting hole. The venting box 17 is locked inside the venting groove 16 by an internal hex bolt. The venting box 17 has a vertical slot 18 inside. Five venting plates 13 are stacked in parallel inside the slot 18. Each venting plate 13 is 5mm thick. The three sides of the venting plate 13 closest to the glue position are machined with shallow venting grooves with a depth of 0.04mm. A 0.5mm air passage is opened at the bottom. Each venting plate 13 has a pin hole in the center. A horizontal pin 19 passes through all the pin holes to lock the venting plates 13 into the venting box 17, assembling them into an integrated venting mechanism 3.

[0029] The working process of this utility model is as follows: 1. During the mold closing and injection molding stage, such as Figure 3 As shown: the upper injection mold (not shown in the figure) and the lower injection mold are closed, the molten plastic fills the mold cavity, and the core mold 2 moves down and presses against the middle upper surface of the fixed lower mold 1; the gas carried by the melt is collected through the shallow venting groove on the surface of the venting plate 13, gathers along the bottom air duct, and is finally discharged outside the mold through the venting hole to avoid gas retention and the formation of gas marks and weld lines.

[0030] 2. During the mold opening and ejection stage, such as Figure 1 and Figure 2 As shown: the upper injection mold (not shown in the figure) is raised first, and then the injection molding machine drives the lifting plate 6 to rise upward. The lifting plate 6 simultaneously drives the main push rod 10 to tilt upward and push out. The main push rod 10 pushes the core mold 2 to lift the injection workpiece 15. When the lifting plate 6 is raised, the translation slide 8 moves upward simultaneously. The guide slider 9 translates along the horizontal guide groove 11 and slides along the axial direction of the inclined support rod 4, which drives the core mold 2 to perform a tilted support that combines vertical rising with horizontal backward movement, so as to disengage from the workpiece undercut position of the injection workpiece 15 and complete stable demolding.

[0031] It should be noted that because the main push rod 10 is inclined according to the ejection direction of the core mold, the translation of the guide slider 9 along the horizontal guide groove 11 solves the structural self-locking problem between the main push rod 10 and the fixed lower mold 1 during the inclined upward movement, allowing the main push rod 10 to smoothly penetrate the fixed lower mold 1 and slide axially to eject / reset. However, regardless of whether the inclined support rod 4 is installed, the movement posture of the main push rod 10 will not change. The function of the inclined support rod 4 is to provide guiding constraints for the guide slider 9 fixed at the bottom of the main push rod 10, so as to constrain the radial force on the main push rod 10, avoid the radial force being too large and causing deformation of the inner wall of the horizontal guide groove 11, and also avoid the guide slider 9 getting stuck at a certain deformation position of the horizontal guide groove 11.

[0032] 3. Mold maintenance stage: Remove the internal hex bolts on the core mold 2 to remove the entire exhaust box 17 assembly; pull out the horizontal pin 19 to separate each exhaust plate 13 individually, clean the carbon deposits in the exhaust groove 16 or directly replace the damaged exhaust plate 13 without disassembling the entire core mold 2, making maintenance convenient.

[0033] Finally, any aspects of this utility model not fully described herein utilize existing mature products and technologies.

[0034] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited to this. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A lower injection mold with a venting and anti-sticking ejection mechanism, wherein the lower injection mold and the upper injection mold together form an injection molding processing area; characterized in that: The injection molding lower mold includes a fixed base plate, a lifting ejection mechanism, and a fixed lower mold. The lifting ejection mechanism is fixedly equipped with an exhaust mechanism that connects the inside and outside of the injection molding processing area. The lifting ejection mechanism is connected to the lifting base plate by a lifting guide, and the fixed lower mold is fixedly supported above the fixed base plate. The lifting ejection mechanism and the fixed lower mold cooperate with the injection molding upper mold to form the injection molding processing area. The fixed base plate has multiple vertical support rods fixedly connected to its four corners. The middle section of the vertical support rod is fitted with a lifting and ejection mechanism, and the top of the vertical support rod is fixedly connected to the lower mold. The lifting and ejection mechanism includes a lifting plate, a translation slide, an inclined support rod, a main push rod, a guide slider, and a core mold; wherein: The lifting plate is mounted on a vertical support rod, and multiple translation slide blocks are fixed on the top surface of the lifting plate. The vertically limited and laterally sliding support guide slider is located on the translation slide block; The guide slider is fixed to the bottom end of the main push rod, and the middle part of the guide slider is slidably fitted onto the inclined support rod. The upper part of the main push rod slides axially through and fixes the lower mold, and the top of the main push rod fixes and supports the core mold. The venting mechanism is provided on the core mold, and the core mold slides down and overlaps the top surface of the fixed lower mold.

2. The injection mold with venting and anti-sticking ejection mechanism according to claim 1, characterized in that: The lifting plate has a vertical through-hole in the middle; the top of the inclined support rod is fixed to the bottom surface of the fixed lower mold, the middle section of the inclined support rod penetrates the through-hole, and the bottom end of the inclined support rod is fixed to the top surface of the fixed base plate.

3. The injection mold with venting and anti-sticking ejection mechanism according to claim 1, characterized in that: The side wall of the translation slide is provided with a horizontally extending guide groove; the guide slider is inclined to support the main push rod, and horizontally arranged wing plates are fixed on both sides of the guide slider; the horizontal wing plates are slidably inserted into the horizontal guide groove, and are vertically constrained and horizontally slidably connected inside the horizontal guide groove.

4. The injection mold with venting and anti-sticking ejection mechanism according to claim 1, characterized in that: A gap for injection molding is left between the edge of the core mold and the top surface of the fixed lower mold.

5. The injection mold with venting and anti-sticking ejection mechanism according to claim 1, characterized in that: The venting mechanism includes a venting groove, a venting box, and multiple venting plates; the venting groove is formed on the injection molding working surface of the core mold, the venting box is fixedly connected to the venting groove with bolts, and the venting groove is in communication with the gas inside and outside the injection molding processing area.

6. The injection mold with venting and anti-sticking ejection mechanism according to claim 5, characterized in that: The exhaust box has a vertical through slot in the middle, and multiple exhaust plates are inserted into the slot in a gap fit and in parallel arrangement.

7. The injection mold with venting and anti-sticking ejection mechanism according to claim 6, characterized in that: Multiple pins are horizontally inserted and fixed to the exhaust box, and the pins fix the exhaust plate inside the slot.

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