Product injection molding process and injection mold and its bottom mold and flow guide mold

Abstract

This invention discloses a bottom mold core for an injection mold, comprising a core body with a product cavity for molding a product. An inlet for the product cavity connects to a gate. One or more flow guide blocks are disposed within the inlet to divert fluid flowing in from the gate and guide it into the product cavity. In this bottom mold core, flow guide blocks are used to divert the flowing fluid, thereby reducing molding pressure and converting turbulent flow to laminar flow. This ultimately achieves fluid flow direction control, effectively reducing defects such as internal bubbles and flow marks in the product, thus improving the product yield. Therefore, it effectively solves the problem of poor molding results in the injection molding process of low-viscosity fluids. The invention also discloses a flow guide mold core for molding the aforementioned bottom mold core, an injection mold including the aforementioned bottom mold core, and a product injection molding process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of product injection molding, more particularly, to a bottom mold core of an injection mold, further to a flow guide mold core of an injection mold for molding the bottom mold core, further to an injection mold comprising the bottom mold core, and further to a product injection molding process. BACKGROUND

[0002] As shown in Figure 1 , Figure 1 is a structural schematic diagram of a pouring system in the prior art, wherein the pouring system is a necessary component in an injection mold. The conventional pouring system in the injection mold comprises a main nozzle, a flow channel, and a gate. The injection machine pours the molten resin into the main nozzle, passes through the flow channel, and then enters the product mold cavity through the gate, so as to achieve the purpose of injection molding products.

[0003] In the conventional mold, the viscosity of the plastic in the molten state is usually relatively high (such as ABS / PC in the molten state, the viscosity is 260 Pa·s (Pascal·second)). Under the driving of the injection pressure, the fluid presents a laminar flow mode, and a product with good quality can be obtained.

[0004] However, for a fluid with low viscosity (viscosity <1 Pa·s), under the driving of high pressure, it will present a turbulent flow mode in a mold cavity with high wall thickness, and in the flow process, the melt will entrain a large amount of gas inside the melt, which finally leads to a large number of bubbles, flow marks and other defects in the product.

[0005] At present, the common solution is to improve by reducing the injection pressure, but low pressure will lead to difficulties in molding filling and shrinkage defects of the product.

[0006] In summary, how to effectively solve the problem of poor molding effect in the injection molding process of a fluid with low viscosity is a problem that needs to be solved by the technical personnel in the field at present. SUMMARY

[0007] Therefore, the first object of the present application is to provide a bottom mold core of an injection mold, which can effectively solve the problem of poor molding effect in the injection molding process of a fluid with low viscosity. The second object of the present application is to provide a flow guide mold core of an injection mold for molding the bottom mold core. The third object of the present application is to provide an injection mold comprising the bottom mold core. The fourth object of the present application is to provide a product injection molding process.

[0008] In order to achieve the first object, the present application provides the following technical scheme:

[0009] A bottom mold core of an injection mold includes a mold core body, the mold core body being provided with a product cavity for molding a product, the inlet of the product cavity being used to connect to a gate, and one or more guide blocks being provided in the inlet to divert fluid flowing in from the gate to the product cavity.

[0010] In this injection mold, a guide block is installed at the inlet of the product cavity in the bottom mold core. During use, when fluid flows from the gate to the inlet, it no longer flows directly forward, but is first diverted by the guide block and then guided in different directions. The guide block in this bottom mold core serves to divert the flowing fluid, thereby reducing molding pressure and changing turbulent flow to laminar flow. Ultimately, this achieves flow direction control, effectively reducing defects such as internal bubbles and flow marks in the product, thus improving the product yield. In summary, this injection mold bottom mold core effectively solves the problem of poor molding results in the injection molding process of low-viscosity fluids.

[0011] Preferably, the guide block is injection molded onto the cavity wall of the product.

[0012] Preferably, the cross-section of the guide block gradually decreases in the direction away from the gate, and the end face of the guide block near the gate forms a guide surface that directs flow to both sides.

[0013] Preferably, the height of the guide block gradually decreases.

[0014] Preferably, the guide block is spindle-shaped or teardrop-shaped.

[0015] Preferably, the plurality of the guide blocks are distributed along an arc, and the included angle between at least one group of adjacent guide blocks is an acute angle.

[0016] To achieve the second objective mentioned above, the present invention also provides a flow guide mold core for injection molds, which is used to form flow guide blocks on the mold core body of any of the aforementioned bottom mold cores. The forming side of the flow guide mold core has a plurality of flow guide block cavities for forming the flow guide blocks. Since the aforementioned bottom mold core has the above-mentioned technical effects, the flow guide mold core should also have corresponding technical effects.

[0017] To achieve the third objective mentioned above, the present invention also provides an injection mold comprising a bottom mold core as described above, and a top mold core, the top mold core covering the bottom mold core to close the product cavity on the bottom mold core. Since the bottom mold core described above has the aforementioned technical effects, the injection mold should also have corresponding technical effects.

[0018] To achieve the third objective mentioned above, the present invention also provides a product injection molding process, comprising the following steps: Step 100: At the inlet of the product cavity of the bottom mold core, a guide block for diverting the fluid flowing in from the gate is injection molded, i.e., any of the aforementioned bottom mold cores is molded; Step 200: The top mold core and the bottom mold core are combined to form a closed product cavity, and the fluid for molding the product is injected into the product cavity through the gate. Since the aforementioned bottom mold core has the above-mentioned technical effects, the product injection molding process should also have corresponding technical effects. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a structural schematic diagram of a casting system existing in the prior art;

[0021] Figure 2 This is a schematic diagram of the structure of the bottom mold core of the injection mold provided in an embodiment of the present invention;

[0022] Figure 3 for Figure 2 A magnified structural diagram of the guide block in the middle;

[0023] Figure 4 This is a schematic diagram of the distribution structure of the guide block provided in an embodiment of the present invention.

[0024] The following labels are shown in the attached diagram:

[0025] Main nozzle 100, runner 200, gate 300, product 400;

[0026] Product cavity 1, gate 2, guide block 3, inlet 4. Detailed Implementation

[0027] This invention discloses a bottom mold core for injection molding, which effectively solves the problem of poor molding effect in the injection molding process of low viscosity fluids.

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Please see Figures 2-4 , Figure 2 This is a schematic diagram of the structure of the bottom mold core of the injection mold provided in an embodiment of the present invention; Figure 3 for Figure 2 A magnified structural diagram of the guide block in the middle; Figure 4 This is a schematic diagram of the distribution structure of the guide block provided in an embodiment of the present invention.

[0030] In some embodiments, a structure for controlling the flow direction of fluids during the molding process of low-viscosity plastics is provided. This structure mainly includes one or more guide blocks 3 arranged at the product gate 2. The guide blocks 3 are flow direction controllers; for example, multiple guide blocks 3 at different angles can be arranged to control the direction of fluid flow. Simultaneously, the one or more guide blocks 3 divert the fluid flow, thereby reducing molding pressure and converting turbulent flow to laminar flow. Ultimately, fluid flow direction control is achieved.

[0031] like Figure 2 As shown, a bottom mold core for an injection mold is provided, wherein the bottom mold core is configured to cooperate with a top mold core to form a closed mold. The bottom mold core is generally a lower mold core, and the top mold core is generally an upper mold core. The main part or at least half of the cavity of the final product is located on the bottom mold core.

[0032] For ease of description, the main part of the bottom mold core is referred to as the mold core body in various embodiments of the present invention. The mold core body is provided with a product cavity 1 for molding the product. The product cavity 1 can be a part of the structure of the final product cavity, or it can be the entire structure.

[0033] Furthermore, the inlet 4 of the product cavity 1 of the mold core body is used to connect the gate 2. The gate 2 of the gating system also needs to be connected to the runner and the main nozzle in sequence so that the fluid casting material, such as plastic, can be injected through the main nozzle. The fluid casting material enters the runner, then flows into the gate 2, and then flows from the gate 2 into the inlet 4 and then into the product cavity 1.

[0034] One or more guide blocks 3 are provided within the inlet 4 to divert the fluid flowing in from the gate 2 and guide it into the product cavity 1. When one guide block 3 is provided, it directs the fluid flowing in from the gate 2 in different directions, serving both diversion and guidance functions. When multiple guide blocks 3 are provided, at least two guide blocks 3 are provided to divert the fluid flowing in from the gate 2 and guide it in different directions. The direction of the guidance is not limited; its main function is to divert and guide the fluid to disperse its flow, thereby mitigating turbulence.

[0035] In the bottom mold core of this injection mold, a guide block 3 is installed at the inlet 4 of the product cavity 1. During use, when the fluid flows from the gate 2 to the inlet 4, it no longer flows directly forward, but is first diverted by the guide block 3 and then guided in different directions. The guide block 3 in this bottom mold core serves to divert the flowing fluid, thereby reducing molding pressure and changing turbulent flow to laminar flow. Ultimately, this achieves flow direction control, effectively reducing defects such as internal bubbles and flow marks in the product, thus improving the product yield. In summary, the bottom mold core of this injection mold can effectively solve the problem of poor molding results in the injection molding process of low-viscosity fluids.

[0036] In some embodiments, during injection molding or reaction molding, when the fluid enters the product cavity 1 through the flow channel, the flow state of the low-viscosity, high-pressure turbulent fluid is corrected to a laminar flow mode as it flows through the grid-like channels composed of controllers, and flows in the direction of the controllers. The grid composed of multiple flow controllers also serves to reduce the flow pressure.

[0037] In some embodiments, the guide block 3 can be injection molded onto the cavity wall of the product cavity 1. Naturally, the injection-molded guide block 3 should not be damaged, or at least not completely damaged, when the fluid of the molded product is introduced. If the casting material of the molded product is cured by cooling, then the melting point of the casting material should be lower than the melting point of the guide block 3; or if the casting material of the molded product is cured by oxidation, then the oxidation process will not affect the guide block 3 from maintaining its current shape. It should be noted that the flow rate of the fluid casting material from the gate 2 to the product cavity 1 is very slow. Since there is a certain adhesion between the injection-molded guide block 3 and the mold core body, the slow-flowing casting material will not damage the position of the guide block 3 relative to the mold core body. Of course, the adhesion between the guide block 3 and the mold core body can also be adjusted in other ways to ensure that the flowing fluid casting material does not damage the adhesion between the guide block 3 and the mold core body. At this time, the flow guide can be injection molded in a two-color injection molding process. After the two-color part is formed, it completely covers the one-color part, which has no impact on the appearance of the part. That is, the final product can cover the flow guide block 3, so that the appearance will not be greatly affected.

[0038] In some embodiments, the guide block 3 can be directly manufactured as an insert, i.e., a pre-formed guide block 3 is installed on the cavity wall of the product cavity 1 of the mold core body. Specifically, the installation method can be bonding, welding, screw connection, etc. The guide block 3 can be a metal block or injection molded in another mold.

[0039] In some embodiments, the cross-section of the guide block 3 can gradually decrease in the direction away from the gate 2, and the end face of the guide block 3 near the gate 2 forms a guide surface that directs the flow to both sides. This allows the guide surface of the guide block 3 to guide the fluid castable to both sides, and because the cross-section of the guide block 3 gradually decreases, the influence of the guide block 3 on the flow of the castable can be gradually reduced, while effectively avoiding the guide block 3 occupying too much space.

[0040] In some embodiments, the height of the guide block 3 can be gradually reduced, which allows the subsequent flow of the fluid to be configured accordingly through the remaining space in the product cavity 1 after the fluid is diverted and guided. This also further ensures the connection performance of the various parts of the product in the lateral direction of the gate 2.

[0041] In some embodiments, multiple guide blocks 3 can be distributed along an arc to form a fan-shaped distribution, and the included angle between at least one group of adjacent guide blocks 3 is an acute angle, so as to guide the flow in different directions. The specific structure of the guide blocks 3 and the distribution method among the multiple guide blocks 3 can also be set as needed, mainly to achieve the effects of diverting and guiding the flow, and the guiding is to guide the inflowing fluid out in a fan-shaped manner.

[0042] In some embodiments, as shown in the appendix Figure 3 As shown, the flow pattern can be controlled by adjusting the spacing 'a' between adjacent guide blocks 3 and the included angle 'b' between adjacent guide blocks 3. For example, the spacing 'a' can be adjusted according to the viscosity of the fluid castable to ensure that the fluid can flow between adjacent guide blocks 3. Generally, the larger the spacing, the better the guiding effect. The larger the included angle 'b', the better the dispersion effect.

[0043] In some embodiments, the guide block 3 can be approximately spindle-shaped or teardrop-shaped, or as shown in the attached figure. Figures 2-4 As shown, it is approximately plate-shaped.

[0044] Based on the bottom mold core of the injection mold provided in the above embodiments, the present invention also provides a flow guide mold core for an injection mold. This flow guide mold core is used to form flow guide blocks 3 on the mold core body of the bottom mold core described in any of the above embodiments. The forming side of the flow guide mold core has multiple cavities for forming the flow guide blocks 3, so that when the flow guide mold core and the bottom mold core are closed, they combine to form closed cavities of each flow guide block 3, and then fluid is poured in to form the flow guide blocks 3. Since this flow guide mold core is used in the bottom mold core of the above embodiments, the beneficial effects of this flow guide mold core are explained in the above embodiments.

[0045] Based on the bottom mold core of the injection mold provided in the above embodiments, the present invention also provides an injection mold, which includes a bottom mold core as described in any of the above embodiments, and further includes a top mold core, with the product cavity 1 on the bottom mold core to be closed. Since this injection mold uses the bottom mold core as described in the above embodiments, the beneficial effects of this injection mold are explained in the above embodiments.

[0046] Based on the bottom mold core of the injection mold provided in the above embodiments, the present invention also provides a product injection molding process, including the following steps:

[0047] Step 100: At the inlet 4 of the product cavity 1 of the bottom mold core, a guide block 3 for diverting the fluid flowing in from the gate 2 is injection molded.

[0048] The bottom mold core of the molding die is closed with the aforementioned guide mold core to form a closed cavity for the guide block 3. Then, fluid is introduced through the gate 2 connected to the inlet 4 of the bottom mold core into the cavity of the guide block 3. After the guide block 3 is formed, the guide mold core is demolded, and the gate 2 is disconnected. This forms the bottom mold core protected in the above embodiment, where the guide block 3 is formed at the inlet 4 of the product cavity 1.

[0049] Step 200: Combine the top mold core and the bottom mold core to form a closed product cavity 1, and inject the fluid of the molded product into the product cavity 1 through the gate 2.

[0050] The bottom mold core, which has already been injection molded with the guide block 3, is combined with the top mold core to form a closed product cavity 1. Then, the gating system gate 2 is connected to introduce fluid casting material through the gate 2 to mold the product. During the demolding process, the bottom mold core, the product, and the guide block 3 can all be demolded.

[0051] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0052] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. 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 invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A bottom mold half of an injection mold, comprising a mold half body provided with a product cavity for forming a product, an inlet of the product cavity being intended for connection of a gate, characterized in that, A plurality of flow guiding blocks are arranged in the inlet to divide the fluid flowing from the gate and guide the fluid into the product cavity; The flow guiding blocks are injection molded on the cavity wall of the product cavity; The cross section of the flow guiding blocks gradually decreases in the direction away from the gate, and the end face of the flow guiding blocks close to the gate forms a flow guiding surface guiding the fluid to both sides; The flow guiding blocks are shuttle-shaped or drop-shaped; The flow guiding blocks are arranged along an arc, and the included angle between at least one group of adjacent flow guiding blocks is an acute angle.

2. The bottom mold core of claim 1, wherein, The height of the flow guiding blocks gradually decreases.

3. A flow guide core for an injection mold, characterized in that A mold block body for forming flow guiding blocks on the mold block body of the bottom mold block as claimed in any one of claims 1-2, the flow guiding block forming side of the mold block has a plurality of flow guiding block cavities for forming the flow guiding blocks.

4. An injection mold comprising a cover mold core, characterized in that Also comprising the bottom mold block as claimed in any one of claims 1-2, the cover mold block covers the bottom mold block to close the product cavity on the bottom mold block.

5. A product injection molding process, suitable for use with the under mold core of any of claims 1-2, characterized in that, The method comprises the following steps: Step 100: injection molding flow guiding blocks for dividing the fluid flowing from the gate at the inlet of the product cavity of the bottom mold block; Step 200: combining the cover mold block with the bottom mold block to form a closed product cavity, and injecting the fluid for forming the product into the product cavity through the gate.

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