Injection mold
By designing a structure in the injection mold where the front arc wall of the runner matches the cavity wall, the problem of reduced molten plastic flow and temperature caused by the gate runner is solved, thereby improving the filling degree of the molten plastic in the cavity and the product quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HEFEI CONVER HLDG
- Filing Date
- 2025-06-20
- Publication Date
- 2026-08-04
AI Technical Summary
In the existing technology, the gate runner design causes the flow rate of molten plastic to decrease and the temperature to drop rapidly when it flows through the gate. This results in insufficient filling of the molten plastic in the cavity and an increased probability of gate marks, which affects product quality.
Design an injection mold in which the front arc wall of the runner fits into the cavity wall and gradually extends towards the cavity wall to ensure a stable flow of the injection medium into the cavity and avoid rapid decrease in flow rate and temperature. The structure adopts a gradually decreasing opening between the front arc wall of the runner and the inner mold.
This improves the filling degree of molten plastic in the mold cavity, reduces the probability of gate marks, and ensures product quality.
Smart Images
Figure CN224588504U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of plastic bumper shell production technology, specifically to an injection mold. Background Technology
[0002] The molding of automotive plastic bumper shells is mainly achieved through injection molding. First, the plastic raw material is heated to a molten state, and then injected into the mold through an injection molding machine. After pressure holding and cooling to solidify, the molded bumper shell is finally obtained by demolding.
[0003] like Figure 1-4 As shown, a bumper flange A1 is provided on the side of the plastic bumper body A facing the vehicle body. The bumper flange A1 also has inserts A11 (such as insert plates) and connectors A12 (such as check claws) for connecting to the vehicle body. Inserts A11 and connectors A12 are spaced apart along the length of the flange A1. Generally, the plastic bumper body A, the bumper flange A1, and the inserts A11 and connectors A12 on it are all injection molded in one step. The molding die includes an outer mold B1 for molding the outer side of the plastic bumper body A and an inner mold B2 for molding the inner side of the plastic bumper body A. The outer mold B1 and the inner mold B2 are parted at the bumper flange A1. The sprue channels L are also spaced along the bumper flange A1, introducing the injection medium into the mold cavity N through multiple sprue channels L to ensure the fullness of the molten plastic in the cavity. However, due to the small edge thickness of the bumper flange A1 (generally 1.2mm), the bumper flange... The cavity thickness corresponding to the suspended edge of A1 is very small, so the thickness of the gate runner connected to the cavity at this location is also very small. Moreover, the length of the rear section L1 of the gate runner (the section that connects to the cavity wall corresponding to the suspended edge of flange A1) is 3-4 times the length of the cavity wall S corresponding to the suspended edge of flange A1. When the gate size is small and the gate length is large, when the molten plastic flows through the gate runner L, the flow rate of the molten plastic decreases and the temperature of the molten plastic drops rapidly, resulting in poor flow performance of the molten plastic, reduced melting performance of the melt, low filling degree of the molten plastic in the cavity, and increased probability of gate marks, thus reducing product quality. Utility Model Content
[0004] The purpose of this invention is to provide an injection mold that allows molten plastic to maintain good flow properties after flowing through the gate runner, thereby improving the filling degree of molten plastic in the cavity.
[0005] This utility model can be achieved through the following technical solution: an injection mold, wherein an outer mold and an inner mold are closed to form a cavity for forming a molded flange and an insert and connector extending on the molded flange; the flow channel of the injection medium is formed by the cavity opening on the outer mold facing the inner mold and the mold surface of the inner mold resting on the cavity opening of the cavity; the outlet of the flow channel is connected to one side of the cavity wall corresponding to the suspended edge of the molded flange; the flow channel includes a rear wall of the flow channel away from the molded flange and a front arc wall of the flow channel that gradually extends towards the molded flange from far to near; the position and opening of the flow channel formed by the end of the front arc wall of the flow channel and the inner mold match the position and opening of one side of the cavity wall corresponding to the suspended edge of the molded flange; the flow channel is connected to the supply channel of the injection medium.
[0006] Compared with the prior art, the present invention has the following beneficial effects:
[0007] The arc wall at the front of the runner prevents the flow rate of the injection medium from decreasing drastically as it continues to flow. This avoids a rapid drop in the temperature of the injection medium, thus preventing a significant reduction in its fluidity and fusion properties, and ensuring the fullness of the injection medium in the cavity. Furthermore, the high fluidity and fusion properties of the injection medium also reduce the likelihood of gate marks. Attached Figure Description
[0008] Figure 1-3 This is a schematic diagram of the structure of a plastic bumper body in the prior art;
[0009] Figure 4 This is a cross-sectional view of the outer mold and inner mold in the closed state in the prior art;
[0010] Figure 5 This is a partial structural diagram of the outer mold at the forming flange position in this application;
[0011] Figure 6 for Figure 5 Enlarged view of a portion of region D;
[0012] Figure 7a , 7b This is a cross-sectional view of the outer mold and inner mold in the mold-closed state in this application;
[0013] Figure 8 for Figure 7a Enlarged view of a portion of region E in the middle. Detailed Implementation
[0014] Please see Figure 5-8As shown, an injection mold is provided, in which an outer mold 10 and an inner mold 20 are closed to form a cavity M for forming a flanged flange A1 and an insert A11 and a connector A12 extending on the flanged flange A1. The flow channel K of the injection medium is formed by the cavity portion of the outer mold 10 facing the inner mold 20 and the mold surface of the inner mold 20 abutting the cavity portion. The outlet K1 of the flow channel K is connected to one side of the cavity wall corresponding to the suspended edge of the flanged flange A1. The flow channel K includes a rear wall 11 away from the flanged flange A1 and a front arc wall 12 that gradually extends towards the flanged flange A1 from far to near. The position and opening of the flow channel formed between the end section 121 of the front arc wall 12 and the inner mold 20 match the position and opening of one side of the cavity wall corresponding to the suspended edge of the flanged flange A1. The flow channel K is connected to the supply channel of the injection medium.
[0015] In the above scheme, the injection medium flows into the cavity M along the main runner and each runner K. Due to the setting of the front arc wall 12 of the runner, the injection medium is stably and quickly introduced into the cavity, so that the injection medium entering the runner K will not immediately experience a significant reduction in flow rate during the continued flow process. This avoids a rapid drop in the temperature of the injection medium, thereby preventing a significant reduction in the fluidity and fusion performance of the injection medium, thus ensuring the fullness of the injection medium in the cavity. Moreover, the injection medium with high fluidity and fusion performance also reduces the probability of gate marks, thereby ensuring product quality.
[0016] Furthermore, the opening of the runner formed by the front arc wall 12 and the inner mold 20 gradually decreases along the direction extending towards the flange A1. This setting ensures that the inlet end of the runner K maintains a large flow rate, and the flow rate of the injection medium gradually decreases as it flows towards the cavity, avoiding a rapid drop in the temperature of the injection medium, thereby ensuring the fluidity and fusion performance of the melt.
[0017] The extension length of the last section 121 of the front arc wall 12 of the runner matches the overhang distance of the suspension edge of the wheel guard flange A1; preferably, the extension length of the last section 121 of the front arc wall 12 of the runner is less than the overhang distance of the suspension edge of the wheel guard flange A1; by reducing the length of the last section 121, the temperature of the injection medium will not drop significantly when it flows out from the outlet K1, thereby ensuring the fluidity and fusion performance of the melt.
[0018] Preferably, the radius R of the arc of the front arc wall 12 of the flow channel is in the range of 10mm-20mm; the radius R of the arc of the front arc wall 12 of the flow channel can be fixed, that is, the front arc wall 12 of the flow channel is a segment of an arc on the same circle, or it can be variable, that is, the front arc wall 12 of the flow channel is composed of multiple segments of arcs with different radii, such as Figure 7b As shown, the radius R of the arc wall 12 at the front of the flow channel increases from upstream to downstream.
Claims
1. An injection mold characterized by: The outer mold (10) and the inner mold (20) are closed to form a molded vehicle flange (A1) and a cavity (M) for the insert (A11) and connector (A12) extending from the vehicle flange (A1). The flow channel (K) of the injection medium is formed by the cavity portion of the outer mold (10) facing the inner mold (20) and the mold surface of the inner mold (20) abutting the cavity portion. The outlet (K1) of the flow channel (K) is connected to the vehicle flange (A1). A1) On one side of the cavity wall corresponding to the suspension edge, the runner (K) includes the runner rear wall (11) away from the car body flange (A1) and the runner front arc wall (12) that gradually extends towards the car body flange (A1) from far to near. The position and opening of the runner formed between the end section (121) of the runner front arc wall (12) and the inner mold (20) match the position and opening of the cavity wall on one side corresponding to the suspension edge of the car body flange (A1). The runner (K) is connected to the supply channel of the injection medium.
2. The injection mold of claim 1, wherein: The opening of the flow channel formed between the front arc wall (12) and the inner mold (20) gradually decreases along the direction extending towards the machine tool flange (A1).
3. Injection mold according to claim 1 or 2, characterized in that: The extension length of the last section (121) of the front arc wall (12) of the flow channel matches the overhang distance of the suspension edge of the vehicle guard flange (A1).
4. The injection mold of claim 3, wherein: The extension length of the last section (121) of the front arc wall (12) of the flow channel is less than the overhang distance of the suspension edge of the vehicle guard flange (A1).
5. Injection mold according to claim 1 or 2, characterized in that: The radius R of the arc wall (12) of the flow channel is in the range of 10mm-20mm.