Mold opening and foaming mechanism and mold opening and foaming injection molding method

Abstract

The application discloses a mechanism for following the opening of a foaming mold and a foaming injection molding method, wherein the mechanism comprises an ejection pull rod, a spring, a limiting component and an edge forming part, the edge forming part is arranged around the product forming cavity of the back mold, the inner side wall of the edge forming part is vertically flush with the outer edge of the product forming cavity, the edge forming part slides relative to the back mold through the ejection pull rod installed at the bottom of the edge forming part, the lower end of the ejection pull rod is sleeved with the spring, one end of the spring abuts against the ejection pull rod, and the other end of the spring abuts against the ejector pin plate, the limiting component is arranged at the upper end of the ejection pull rod and comprises a limiting sleeve installed on the ejection pull rod and a limiting block installed on the back mold, and all the edge forming parts are synchronously ejected. The application has the advantages of simple structure, easy realization, low mold cost and high reliability, can avoid the change of the shape under the action of the internal foaming force, will not cause the overflow of the molten glue, realizes the non-overflow and non-bulging of the product edge, improves the surface quality of the product and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of injection mold forming, in particular to a traveling mechanism of a mold-opening foaming mold and a mold-opening foaming injection molding method. BACKGROUND

[0002] Due to the increasing awareness of energy saving, emission reduction and environmental protection, and the demand of manufacturing industry for cost reduction, mold-opening foaming gradually develops into the most effective injection molding weight reduction technology in the field of injection molding. Using mold-opening foaming technology, the weight of injection molded parts can be reduced by 10-30%. Especially in the automotive industry, using this technology in automotive plastic interiors can greatly reduce the weight of the entire vehicle, achieve lightweight, and achieve the effect of reducing fuel consumption or increasing the cruising range of electric vehicles.

[0003] The mold-opening foaming injection molding technology includes two stages of mold opening process. The first stage of mold opening is to open a small distance when the product is just filled and the freezing degree of the plastic is the lowest. The product expands and thickens under the action of foaming force when the mold is opened in the first stage, and reaches the final product size. Then, the same as the traditional injection molding process, it enters the cooling stage. After the product is cooled, the second stage of mold opening is started, and finally the product is ejected, the mold is closed, and the next cycle is started.

[0004] Because the first stage of mold opening in the mold-opening foaming injection molding process will cause a mold opening gap on the parting surface of the mold, and the first stage of mold opening is just when the freezing degree of the plastic part surface is the lowest. The frozen layer is thin and has low strength, and cannot resist the foaming force of the unfrozen molten layer inside the plastic part. Finally, the product edge near the parting surface gap will expand due to the foaming force, which may slightly protrude from the parting surface gap, or a large amount of molten glue may leak from the parting surface gap, resulting in product appearance defects. SUMMARY

[0005] The purpose of the present application is to solve the problems in the prior art, and provide a traveling mechanism of a mold-opening foaming mold and a mold-opening foaming injection molding method.

[0006] To solve the above technical problems, the technical scheme adopted by the present application is: a kind of follow-up mechanism of open mold foaming mold, it is arranged on the back mould of injection mold, including ejection pull rod, spring, limiting component and edge forming component, wherein edge forming component is segmented, sequentially head-to-tail, ring around the four around product forming cavity of back mould, extend as a whole along the length direction of edge forming component, the inner side wall of edge forming component is vertically flush with the outer edge of product forming cavity;The top surface of the back mould is provided with groove, below edge forming component, edge forming component is contained in the recess of back mould, and the ejection pull rod installed at the bottom thereof slides up and down in the recess;Ejection pull rod extends downward through back mould, and the bottom end thereof is connected to ejector plate below back mould;The lower end of the ejection pull rod is sleeved with spring, one end of the spring abuts against the ejection pull rod, and the other end abuts against the ejector plate;The upper end of the ejection pull rod is provided with a limiting component, and the limiting component includes a limiting sleeve and a limiting block corresponding thereto, the limiting sleeve is fixedly installed on the ejection pull rod, and the limiting block is installed on the back mould;All edge forming components are ejected synchronously.

[0007] Further, the cross section of the edge forming component is in inverted T-shaped structure, and the recess on the back mould is matched therewith;The depth of the upper part of the edge forming component in the opening direction is not less than the distance of the first stage opening of the open mold foaming mold.

[0008] Further, the bottom of each edge forming component is fixedly provided with a plurality of ejection pull rods, to ensure the synchronous ejection of the edge forming component.

[0009] Further, the distance between the top end of the limiting sleeve on the ejection pull rod and the bottom end of the limiting block on the back mould is 1mm in initial mold clamping injection.

[0010] Further, the adjacent two edge forming components are sealed.

[0011] An open mold foaming injection method based on the above-mentioned open mold foaming mold follow-up mechanism, comprising the following steps:

[0012] 1) mold clamping, the follow-up mechanism is in initial state;

[0013] 2) injection of rubber material to fill product forming cavity;

[0014] 3) the first stage opening of foaming mold, all edge forming components are ejected upward synchronously under the action of corresponding spring force, and then product forming foaming cavity is formed, and the rubber material is thickened under the action of foaming force, and reaches the final product size;

[0015] 4) product cooling forming;

[0016] 5) the second stage opening of foaming mold;

[0017] 6) eject the product, take the part, close the mold; the reset of the edge forming part is pressed back by the front mold closing.

[0018] Compared with the prior art, the present application has the following beneficial effects: the present application has simple structure and is easy to implement, can use ordinary structure mold for mold opening foaming injection molding, has low mold cost and high reliability; can avoid shape change under the action of internal foaming force, and also will not cause the overflow of molten glue, plays the role of sealing and limiting, realizes no overflow and no bulging of product edge, improves the surface quality of product. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments will be briefly introduced below,

[0020] Fig. 1 It is a structural schematic view of the accompanying mechanism of the present application (selected section);

[0021] Fig. 2 It is a structure view of the top surface of the rear mold in the present application;

[0022] Fig. 3 It is a structure view of the edge forming part in the accompanying mechanism of the present application;

[0023] In the figure: 1, edge forming part, 2, ejecting pull rod, 3, limiting sleeve, 4, limiting block, 5, rear mold, 6, groove. DETAILED DESCRIPTION

[0024] It should be noted that in the description of the present application, the terms such as "upper", "lower", "front", "rear" and the like indicate the orientation or positional relationship shown in the drawings, which is only a relationship word determined for the purpose of conveniently describing the structural relationship of the components of the present application, and is not a specific orientation, and cannot be understood as a limitation of the present application.

[0025] In addition, unless otherwise specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; can be directly connected, or indirectly connected through intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0026] The specific embodiments of the present application will be further described in detail below in combination with the drawings:

[0027] For example, Figs. 1 to 3As shown, a mechanism for a mold opening foaming mold is arranged on a back mold 5 of an injection mold, and includes an ejection rod 2, a spring, a limiting assembly, and an edge forming component 1. The edge forming component 1 is segmented, sequentially connected end to end, and arranged around the product forming cavity of the back mold 5 according to the actual injection molded product. The edge forming component 1 extends along the length direction to form an integral whole. According to the shape and structure of the injection molded product, each segmented edge forming component 1 presents a different shape to complete the surrounding containment of the entire product forming cavity. Each adjacent two edge forming components 1 are sealed. The inner side wall of the edge forming component 1 is vertically flush with the outer edge of the product forming cavity to prevent overflow of the injection molding material. The upper surface of the back mold 5 is provided with a groove 6 around the product forming cavity and below the edge forming component 1. The groove 6 is arranged in an inverted T shape. The edge forming component 1 is accommodated in the groove 6, and the cross section of the edge forming component 1 is also arranged in an inverted T shape. The edge forming component 1 slides up and down in the groove 6 through the ejection rod 2 installed at the bottom of the edge forming component 1. The ejection rod 2 extends downward through the back mold 5 and is connected to the ejector plate below the back mold 5 at the bottom end. The lower end of the ejection rod 2 is sleeved with a spring. One end of the spring abuts against the ejection rod 2, and the other end abuts against the ejector plate to provide power for the edge forming component 1. The upper end of the ejection rod 2 is provided with a limiting assembly. The limiting assembly includes a limiting sleeve 3 and a limiting block 4 corresponding thereto. The limiting sleeve 3 is fixedly sleeved on the ejection rod 2, and the limiting block 4 is installed on the corresponding position of the back mold 5. The two form a limit. In the initial state of mold clamping and injection, the distance between the top end of the limiting sleeve 3 and the bottom end of the limiting block 4 is the required foaming thickness of the product, which is 1mm according to the product design requirement. Multiple ejection rods 2 are arranged at intervals at the bottom of each edge forming component 1 to ensure synchronous ejection.

[0028] During mold opening foaming injection molding, the first stage mold opening will cause a mold opening gap at the parting surface of the mold. The first stage mold opening is exactly when the surface of the plastic part is at the lowest freezing degree. The frozen layer is thin and has low strength, which cannot resist the foaming force of the unfrozen molten layer inside the plastic part. Finally, the product edge near the parting surface gap will expand due to the foaming force, resulting in bulging or overflow at the product edge. The segmented edge forming component 1 around the product forming cavity is ejected upward together with the opening of the front mold, which jointly encloses the product forming foaming cavity to achieve glue sealing and avoid changes in the shape of the product under the action of internal foaming force. The depth of the upper part of the edge forming component 1 in the opening direction is not less than the distance of the first stage mold opening of the mold opening foaming mold, which also avoids overflow of the molten material.

[0029] The embodiment also provides a mold opening foaming injection molding method based on the mold opening foaming mold mechanism.

[0030] 1) Mold clamping, and the mechanism is in an initial state;

[0031] 2) injection of the rubber compound into the product forming cavity;

[0032] 3) first stage opening of the mold, all the edge forming parts 1 are pushed up synchronously with the front mold under the action of the corresponding spring force, and then form a product forming and foaming cavity, the rubber compound expands and thickens under the action of the foaming force as the first stage opens, and reaches the final product size;

[0033] 4) product cooling and forming;

[0034] 5) second stage opening of the mold;

[0035] 6) ejection of the product, taking out the product, closing the mold; the resetting of the edge forming parts 1 is achieved by pressing back through the closing of the front mold.

[0036] The specific implementation of each step in the above embodiment has not been described in detail, and can be achieved by using or referring to the existing technology, which will not be described here.

[0037] Of course, the above description is not a limitation of the present application, and the present application is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present application should also be within the scope of the present application.

Claims

1. A mechanism for opening a foaming mold, which is provided on a back mold of an injection mold, characterized in that: The ejector rod, spring, limiting assembly and edge forming part are included, wherein the edge forming part is segmented, sequentially connected head to tail, wrapped around the product forming cavity of the back mold, extended as a whole along the length direction of the edge forming part, and the inner side wall of the edge forming part is vertically flush with the outer edge of the product forming cavity; the top surface of the back mold is provided with a groove below the edge forming part, the edge forming part is accommodated in the groove of the back mold, and the ejector rod installed at the bottom thereof slides up and down in the groove; the ejector rod extends downward through the back mold, and the bottom end is connected to the ejector pin plate below the back mold; the lower end of the ejector rod is sleeved with a spring, one end of the spring abuts against the ejector rod, and the other end abuts against the ejector pin plate; the upper end of the ejector rod is provided with a limiting assembly, the limiting assembly includes a limiting sleeve and a limiting block corresponding thereto, the limiting sleeve is fixedly installed on the ejector rod, and the limiting block is installed on the back mold; all the edge forming parts are synchronously ejected. The cross section of the edge forming part is inverted T-shaped structure, and the groove on the back mold is matched therewith; the depth of the upper part of the edge forming part in the opening direction is not less than the distance of the first stage opening of the opening foam mold.

2. The mechanism for carrying the mold foaming mold according to claim 1, wherein: The bottom of each edge forming part is fixedly provided with a plurality of ejector rods, so as to ensure the synchronous ejection of the edge forming part.

3. The mechanism for carrying the mold foaming mold according to claim 1, wherein: The distance between the top end of the limiting sleeve on the ejector rod and the bottom end of the limiting block on the back mold is 1mm.

4. The mechanism for carrying the mold foaming mold according to claim 1, wherein: The adjacent two edge forming parts are sealed.

5. A mold opening and foaming injection molding method based on the mold opening and foaming mold carrier mechanism according to any one of claims 1 to 4, characterized by, The method includes the following steps: 1) mold closing, the follower mechanism is in the initial state; 2) injecting the material to fill the product forming cavity; 3) the first stage opening of the foam mold, all the edge forming parts are synchronously ejected upward with the front mold under the action of the corresponding spring force, and then the product forming foam cavity is formed, the material is thickened under the action of the foaming force, and the final product size is reached; 4) product cooling forming; 5) the second stage opening of the foam mold; 6) ejecting the product, taking the product, closing the mold; the reset of the edge forming part is realized by the closing of the front mold.

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