Test mold and test method for weld mark strength of injection molding product

Abstract

The embodiment of the invention discloses a test mold and a test method for evaluating the weld mark strength of an injection molding product, and the test mold is used for evaluating the weld mark strength of the injection molding product and comprises a fixed mold, a movable mold and a mold core, the fixed mold is fixed on an injection molding machine, the movable mold is detachably connected with the fixed mold, and the mold core is movably arranged in a cavity channel formed by matching the fixed mold and the movable mold in a penetrating manner; a glue injection groove is formed in the mold core, and the glue injection groove is matched with the fixed mold to form a closed mold cavity for simulating a target convergence angle weld line; an injection molding channel communicated with the mold cavity is formed in the fixed mold, and an injection molding opening communicated with the injection molding channel is formed in the end part of the fixed mold. The plastic product with the target convergence angle weld line can be formed in the mold cavity through injection molding, so that the strength of the target convergence angle weld mark on the plastic product is accurately evaluated, the mold cavity with different convergence angle weld lines can be formed by replacing different mold cores, and the application range is wide.

Description

Technical Field

[0001] The invention relates to the technical field of injection molding, and in particular to a method for testing the weld mark strength of a mold and an injection molded product. Background Art

[0002] Injection molding is a manufacturing method for plastic products. The molten plastic is injected into the plastic product mold under pressure and cooled to form the desired plastic parts. During the injection molding process, due to factors such as holes, inserts, sudden changes in wall thickness, and multiple gates, the material flow bifurcates and merges, thus forming weld marks. The presence of weld marks not only affects the apparent quality of the product, but also affects the mechanical properties of the product.

[0003] Conventional weld mark strength test molds cannot directly reflect the convergence state of weld marks on actual products. The reason is that the weld marks on conventional weld mark strength test products converge at a standard 0° angle, and such standard weld marks rarely appear on real products. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a test mold and a test method for evaluating the weld mark strength of an injection molded product to solve the problem that a conventional weld mark strength test mold cannot intuitively reflect the confluence state of the weld mark on the actual product.

[0005] In a first aspect, the present invention provides a test mold, which is used to evaluate the weld mark strength of an injection molded product, and includes: a fixed mold, a movable mold, and a mold core;

[0006] The fixed mold is fixed on the injection molding machine, the movable mold is detachably connected to the fixed mold, and the mold core is movably arranged in a cavity formed by the fixed mold and the movable mold;

[0007] The mold core is provided with a glue injection groove, and the glue injection groove cooperates with the fixed mold to form a closed mold cavity simulating a target convergence angle weld line;

[0008] An injection channel communicating with the mold cavity is provided in the fixed mold, and an injection port communicating with the injection channel is provided at the end of the fixed mold.

[0009] In one embodiment of the above-mentioned test mold, there are at least two glue injection grooves, and the mold core is provided with feed ports respectively connected to the glue injection grooves and the injection channel;

[0010] Each of the feed ports is communicated with at least two of the glue injection grooves.

[0011] In one embodiment of the above-mentioned test mold, a convex portion is provided on the outer surface of the mold core along its axial direction, and a sliding groove matching the convex portion is provided in the movable mold.

[0012] In one embodiment of the above-mentioned test mold, the mold further includes a locking member for limiting the sliding of the mold core in the cavity.

[0013] In one embodiment of the above-mentioned test mold, the locking member includes a locking opening opened at the bottom of the mold core, and a locking pin matched with the locking opening;

[0014] The locking pin is movably mounted on the bottom of the movable mold and is perpendicular to the moving direction of the mold core in the cavity.

[0015] In one embodiment of the above-mentioned test mold, an ejector assembly is installed in the fixed mold, and each of the mold cavities is correspondingly provided with a group of the ejector assemblies;

[0016] After the injection molding is completed, the ejector assembly is driven by the oil pressure ejection mechanism in the injection molding machine to eject the plastic product in the mold cavity.

[0017] In one embodiment of the above-mentioned test mold, the ejector pin assembly includes a first ejector pin and a second ejector pin;

[0018] The first ejector pin lifts the corresponding center point of the mold cavity, the second ejector pin lifts the corresponding edge of the mold cavity, and the second ejector pins are symmetrically distributed around the first ejector pin.

[0019] In one embodiment of the above-mentioned test mold, the fixed mold and the movable mold are connected by pins and / or screws.

[0020] In a second aspect, the present invention provides a method for testing the weld mark strength of an injection molded product, the method using a test mold as described in any one of the first aspects, the method comprising:

[0021] Inserting the mold core into a cavity formed by the fixed mold and the movable mold and fixing it;

[0022] Injecting molten target plastic from the injection port, allowing the molten target plastic to enter the mold cavity of the simulated convergence angle weld line formed by the mold core and the fixed mold through the injection channel, and cooling to obtain an injection molded product;

[0023] Disassembling the movable mold and the mold core, and taking out the injection molded product;

[0024] Cutting a spline of a preset width with the outer end surface of the injection molded product as a starting point;

[0025] The specimens were subjected to tensile, bending and impact tests to evaluate the weld line strength of the injection molded products.

[0026] In one embodiment of the above-mentioned method for testing weld mark strength of injection molded products, before taking out the injection molded product, the method further includes:

[0027] The operation of the hydraulic ejector mechanism in the injection molding machine is controlled to drive the ejector pin in the fixed mold to move and eject the corresponding injection molded product in the mold cavity.

[0028] One or more of the above-mentioned embodiments of the present invention have at least one or more of the following beneficial effects: a mold core is movably arranged in a cavity formed by a detachably connected fixed mold and a movable mold, and a glue injection groove provided on the mold core cooperates with the fixed mold to form a closed mold cavity simulating a target convergence angle weld line, and a plastic product having a target convergence angle weld line can be formed by injection molding into the mold cavity, thereby accurately evaluating the strength of the target convergence angle weld mark on the plastic product, and mold cavities with different convergence angle weld lines can be formed by replacing different mold cores, which has a wide range of applications.

[0029] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The disclosure of the present invention will become more easily understood with reference to the accompanying drawings. It is easy for those skilled in the art to understand that these drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present invention. In addition, similar numbers in the figures are used to represent similar components, among which:

[0031] Figure 1 It is a schematic diagram of the weld mark produced on the injection molded product;

[0032] Figure 2 is a schematic structural diagram of a test mold provided by an embodiment of the present invention;

[0033] Figure 3 is a front view of a mold core in a test mold provided by an embodiment of the present invention;

[0034] Figure 4 is a schematic diagram of the matching process between the mold core and the locking member in the test mold provided by an embodiment of the present invention;

[0035] Figure 5 is a schematic diagram of switchable positions of a mold core in a cavity of a test mold provided by an embodiment of the present invention;

[0036] Figure 6 It is a schematic diagram of the cutting position of the spline in the test method for the weld mark strength of the injection molded product provided in the embodiment of the present invention.

[0037] Among them: 1. fixed mold; 11. injection port; 2. movable mold; 21. slide groove; 3. mold core; 31. injection groove; 32. feed port; 33. convex part; 4. cavity; 5. locking piece; 51. locking port; 52. locking pin. DETAILED DESCRIPTION

[0038] Some embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0039] As described in the background technology, during the injection molding process, factors such as holes, inserts, sudden changes in wall thickness, and multiple gates can cause the molten plastic flow to branch and merge, thus forming Figure 1 The weld marks shown in the figure not only affect the appearance of plastic products, but also their mechanical properties. Therefore, it is necessary to test the weld mark strength of plastic products to determine whether the weld mark strength meets the mechanical property requirements of the product. The weld marks on the current weld mark strength test mold are standard 0° angle convergence, which is rarely seen on real products. Therefore, the current weld mark strength test mold cannot intuitively reflect the convergence state of the weld marks on the actual product, and the weld mark strength test results obtained are not accurate.

[0040] In order to solve the above problems, the present invention creatively proposes a testing method for testing the weld mark strength of molds and injection molded products. A mold core is movably arranged in a cavity formed by a detachably connected fixed mold and a movable mold. A glue injection groove on the mold core cooperates with the fixed mold to form a closed mold cavity that simulates a target convergence angle weld line. Plastic products with target convergence angle weld lines can be injected into the mold cavity to form plastic products, thereby accurately evaluating the target convergence angle weld mark strength on the plastic product. In addition, mold cavities with different convergence angle weld lines can be formed by replacing different mold cores. The method has a wide range of applications.

[0041] The present invention will be described in detail below through specific embodiments.

[0042] The present application embodiment provides a test mold, referring to Figure 1 As shown, the test mold is used to evaluate the weld mark strength of the injection molded product, including: a fixed mold 1, a movable mold 2 and a mold core 3;

[0043] The fixed mold 1 is fixed on the fixed mold base of the injection molding machine, the movable mold 2 is fixed on the movable mold base of the injection molding machine, and the core 3 is movably arranged in the cavity 4 formed by the fixed mold 1 and the movable mold 2; the cavity 4 can be open at both ends or open at one end and closed at the other end, as long as it can accommodate the core 3 and the inner surface of the cavity 4 fits with the outer surface of the core 3.

[0044] The mold core 3 is provided with a glue injection groove 31, which cooperates with the fixed mold 1 to form a closed mold cavity simulating a target convergence angle weld line. By changing the shape of the glue injection groove 31, different convergence angle weld lines of molten plastic can be simulated.

[0045] An injection channel (not shown) communicating with the mold cavity is provided in the fixed mold 1 , and an injection port 11 communicating with the injection channel is provided at the end of the fixed mold 1 .

[0046] A mold core 3 is movably arranged in a cavity formed by a detachably connected fixed mold 1 and a movable mold 2. A glue injection groove 31 provided on the mold core 3 cooperates with the fixed mold 1 to form a closed mold cavity simulating a target converging angle weld line. Plastic products having a target converging angle weld line can be formed by injection molding into the mold cavity, thereby accurately evaluating the strength of the target converging angle weld mark on the plastic product. In addition, mold cavities with different converging angle weld lines can be formed by replacing different mold cores, and the application range is wide.

[0047] In some embodiments, reference Figure 1 and Figure 2 As shown, there are at least two glue injection grooves 31, and the mold core 3 is provided with feed ports 32 respectively connected to the glue injection grooves 31 and the injection channel; each feed port 32 is connected to at least two glue injection grooves 31. At least two glue injection grooves 31 of different shapes are provided, so that different convergence angle weld lines can be obtained at the same time. The feed port 32 is connected to at least two glue injection grooves 31, and the structural space is more compact. The feed port 32 can be set between the glue injection grooves 31, or it can be set above or below the glue injection grooves 31, and the present application does not make any specific restrictions on this.

[0048] In some embodiments, reference Figure 1 and Figure 2 As shown, the outer surface of the mold core 3 is provided with a convex portion 33 along its axial direction, and a slide groove 21 matching the convex portion 33 is provided in the movable mold 2. The matching of the slide groove 21 and the convex portion 33 can limit the sliding path of the mold core 3 when sliding in the cavity 4, and avoid the mold core 3 path being skewed and the mold cavity produced by the fixed mold 1 being unable to close.

[0049] In some embodiments, the mold further includes a locking member 5 for limiting the sliding of the mold core 3 in the cavity 4 .

[0050] Optional, see Figure 3 and Figure 4As shown, the locking member 5 includes a locking opening 51 opened at the bottom of the mold core 3, and a locking pin 52 matched with the locking opening 51; the locking pin 52 is movably installed at the bottom of the movable mold 2 and is perpendicular to the moving direction of the mold core 3 in the cavity 4. Exemplarily, the mold core 3 moves in the cavity 4 along its axial direction, and the central axis of the mold core 3 is horizontally arranged. There are two locking openings 51, which are arranged at the bottom of the mold core 3 along the axial direction of the mold core 3. When the locking pin 52 cooperates with the first locking opening 51, the mold core 3 is assembled and cooperates with the fixed mold 1 to form a closed mold cavity. When the locking pin 52 cooperates with the second locking opening 51, the injection groove 31 on the mold core 3 is completely separated from the fixed mold 1. Through the cooperation of the locking pin 52 and the locking opening 51, the position of the mold core 3 in the cavity 4 can be fixed.

[0051] In some embodiments, an ejector assembly (not shown) is installed in the fixed mold 1, and each mold cavity is correspondingly provided with a group of the ejector assemblies; after the injection molding is completed, the ejector assembly is driven by the oil pressure ejection mechanism in the injection molding machine to eject the plastic product in the mold cavity.

[0052] Optionally, the ejector pin assembly includes a first ejector pin and a second ejector pin; the first ejector pin lifts the center point of the corresponding mold cavity, the second ejector pin lifts the edge of the corresponding mold cavity, and the second ejector pins are symmetrically distributed with the first ejector pin as the center. The first ejector pin lifts the center point of the corresponding mold cavity, the second ejector pin lifts the edge of the corresponding mold cavity, and the second ejector pins are symmetrically distributed with the first ejector pin as the center, thereby evenly applying force to the plastic product injected in the mold cavity, and the plastic product in the mold cavity can be lifted and removed.

[0053] In some embodiments, reference Figure 5 As shown, there are two or more glue injection grooves 31 on the mold core 3, the length of the mold core 3 is greater than the length of the cavity 4, and both ends of the cavity 4 are open. The injection port 11, the injection channel and different feed ports 32 on the mold core 3 are connected by sliding the mold core 3 in the cavity 4 to realize the connection and switching between the injection port 11 and different glue injection grooves 31 on the mold core 3.

[0054] An embodiment of the present invention further provides a method for testing the weld mark strength of an injection molded product. The testing method uses a test mold as described in any one of the above embodiments, and the method includes:

[0055] S1. Insert the mold core into the cavity formed by the fixed mold and the movable mold and fix it.

[0056] S2, injecting molten target plastic from the injection port, allowing the molten plastic to enter the mold cavity of the simulated convergence angle weld line formed by the mold core and the fixed mold through the injection channel, and cooling to obtain an injection molded product;

[0057] S3. Disassemble the movable mold and the mold core and take out the injection molded product.

[0058] S4. Reference Figure 6As shown, a spline of preset width is cut with the outer end surface of the injection molded product as the starting point.

[0059] S5. The specimens are subjected to tensile, bending and impact tests to evaluate the weld line strength of the injection molded products.

[0060] In some embodiments, before removing the injection molded product, the method further comprises:

[0061] SA, control the operation of the hydraulic ejector mechanism in the injection molding machine to drive the ejector pin in the fixed mold to move and eject the injection molded product in the corresponding mold cavity.

[0062] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0063] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0064] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A test mold, characterized in that: The test mold is used to evaluate the weld mark strength of the injection molded product, and includes: a fixed mold, a movable mold and a mold core; The fixed mold is fixed on the injection molding machine, the movable mold is detachably connected to the fixed mold, and the mold core is movably arranged in a cavity formed by the fixed mold and the movable mold; The mold core is provided with a glue injection groove, and the glue injection groove cooperates with the fixed mold to form a closed mold cavity simulating a target convergence angle weld line; An injection channel communicating with the mold cavity is provided in the fixed mold, and an injection port communicating with the injection channel is provided at the end of the fixed mold.

2. The test mold according to claim 1, characterized in that: There are at least two glue injection grooves, and the mold core is provided with feed ports respectively connected to the glue injection grooves and the injection channel; Each of the feed ports is communicated with at least two of the glue injection grooves.

3. The test mold according to claim 1, characterized in that: The outer surface of the mold core is provided with a convex portion along its axial direction, and a sliding groove matching the convex portion is provided in the movable mold.

4. The test mold according to claim 1, characterized in that: The mold further comprises a locking member for limiting the sliding movement of the mold core in the cavity.

5. The test mold according to claim 4, characterized in that: The locking member comprises a locking opening opened at the bottom of the mold core, and a locking pin matched with the locking opening; The locking pin is movably mounted on the bottom of the movable mold and is perpendicular to the moving direction of the mold core in the cavity.

6. The test mold according to claim 1, characterized in that: An ejector assembly is installed in the fixed mold, and each mold cavity is correspondingly provided with a group of ejector assemblies; After the injection molding is completed, the ejector assembly is driven by the oil pressure ejection mechanism in the injection molding machine to eject the plastic product in the mold cavity.

7. The test mold according to claim 6, characterized in that: The ejector pin assembly comprises a first ejector pin and a second ejector pin; The first ejector pin lifts the corresponding center point of the mold cavity, the second ejector pin lifts the corresponding edge of the mold cavity, and the second ejector pins are symmetrically distributed around the first ejector pin.

8. The test mold according to claim 1, characterized in that: The fixed mold is connected to the movable mold via pins and / or screws.

9. A method for testing the weld mark strength of an injection molded product, characterized in that: The method uses the test mold according to any one of claims 1 to 8, and the method comprises: Inserting the mold core into a cavity formed by the fixed mold and the movable mold and fixing it; Injecting molten target plastic from the injection port, allowing the molten target plastic to enter the mold cavity of the simulated convergence angle weld line formed by the mold core and the fixed mold through the injection channel, and cooling to obtain an injection molded product; Disassembling the movable mold and the mold core, and taking out the injection molded product; Cutting a spline of a preset width with the outer end surface of the injection molded product as a starting point; The specimens were subjected to tensile, bending and impact tests to evaluate the weld line strength of the injection molded products.

10. The method for testing the weld mark strength of injection molded products according to claim 9, characterized in that: Before removing the injection molded product, the method further comprises: The operation of the hydraulic ejector mechanism in the injection molding machine is controlled to drive the ejector pin in the fixed mold to move and eject the corresponding injection molded product in the mold cavity.

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