Injection molding process of plastic workpiece and plastic workpiece

Abstract

The application discloses a kind of injection molding process and plastic device of plastic workpiece, the process includes the following steps: the encapsulated end of nut is placed into first mold, and glue is injected into first mold;After the glue in first mold is cooled, injection molding semi-finished product is formed;Injection molding semi-finished product is taken out from first mold, and injection molding semi-finished product is placed into second mold, and glue is injected into second mold;After the glue in second mold is cooled to preset time, injection molding body is formed;Injection molding body is taken out from second mold, and plastic workpiece is obtained.The technical scheme of the embodiment, compared with the traditional one-time injection molding forming mode, does not need to additionally use fixing member to fix the nut, can ensure that the nut will not move due to the impact force during injection molding, and improves the quality of product.

Description

Technical Field

[0001] This invention relates to the field of in-mold injection molding technology, and in particular to an injection molding process for plastic workpieces and the plastic workpieces thereof. Background Technology

[0002] In some components, nuts need to be embedded within plastic parts to form plastic workpieces, facilitating subsequent assembly and fixation by screws. Currently, these plastic workpieces are obtained through a one-step injection molding process: the nut is placed into a mold, then plastic material is injected, and after cooling, a plastic overlay forms around the nut, resulting in the plastic workpiece. Because of the different shrinkage rates of the nut and the overlay plastic during cooling in this one-step injection molding process, the gap between them needs to be filled with plastic material to ensure a stable connection. However, during the filling process, the nut is subjected to impact force along the direction of plastic material filling, causing it to move and resulting in defective plastic workpieces that cannot meet subsequent assembly requirements. Summary of the Invention

[0003] To solve the above-mentioned technical problems, the present invention provides an injection molding process for plastic workpieces and the plastic workpieces thereof.

[0004] In a first aspect, embodiments of this application provide an injection molding process for a plastic workpiece, comprising the following steps:

[0005] Place the rubber-coated end of the nut into the first mold and inject rubber into the first mold;

[0006] After the rubber material in the first mold cools, it forms an injection-molded semi-finished product;

[0007] The injection-molded semi-finished product is removed from the first mold and placed into the second mold, and then the rubber material is injected into the second mold.

[0008] After the rubber material in the second mold cools to the preset time, an injection molded body is formed;

[0009] The injection molded body is removed from the second mold to obtain a plastic workpiece.

[0010] In one embodiment, during the step of injecting adhesive into the first mold, the adhesive is fed into the first mold in a direction along the width of the nut.

[0011] In one embodiment, during the step of injecting adhesive into the second mold, the adhesive is fed into the second mold along the length direction of the nut.

[0012] In one embodiment, the injection-molded semi-finished product includes a nut and a plastic part, the plastic part being connected to the rubber-coated end of the nut; the plastic part includes a connecting portion and an abutting portion, the abutting portion protruding from the surface of the connecting portion away from the nut, and the connecting portion forming a cavity for connecting with the rubber-coated end of the nut;

[0013] In the step of placing the injection-molded semi-finished product into the second mold, the surface of the abutting part abuts against the second mold.

[0014] In one embodiment, the diameter of the abutting portion is smaller than the diameter of the connecting portion, and the center of the abutting portion and the center of the connecting portion are on the same straight line;

[0015] The diameter of the abutting part is 2 / 3 to 3 / 4 of the diameter of the connecting part.

[0016] In one embodiment, the outer peripheral surface of the rubber-coated end of the nut is provided with a first connecting ring, and the outer surface of the first connecting ring is provided with threads;

[0017] Wherein, when the plastic part is connected to the nut, the portion of the first connecting ring extending into the cavity occupies 2 / 3 to 4 / 5 of the first connecting ring.

[0018] In one embodiment, the outer circumferential surface of the nut is further provided with a plurality of second connecting rings at intervals, and the outer surface of the second connecting rings is provided with threads.

[0019] In one embodiment, the nut is a copper nut.

[0020] Secondly, this application also provides a plastic workpiece manufactured based on the injection molding process of the plastic workpiece described in the first aspect, the plastic workpiece including a nut, a plastic part and an injection molding component, the plastic part being connected to the rubber-coated end of the nut, and the injection molding component having a receiving cavity for accommodating the plastic part and the nut.

[0021] In one embodiment, the nut is made of brass.

[0022] Compared with the prior art, the technical solutions provided in this application have the following advantages:

[0023] First, plastic material is injected into the rubber-coated end of the nut. After the material cools, it wraps around the rubber-coated end of the nut, forming a semi-finished injection molded product. Then, this semi-finished product is placed into a second mold, and plastic material is injected. After the material cools, it wraps around the outside of the semi-finished product, resulting in a plastic workpiece. Compared to the traditional one-time injection molding method, no additional fasteners are needed to secure the nut, ensuring that the nut will not move due to impact during the injection process, thus improving product quality. Furthermore, because the plastic is formed at the rubber-coated end of the nut first, the guide pins in the mold only serve a guiding function during the second injection, without friction with the inner hole of the nut, effectively preventing damage to the threads inside the nut. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of a plastic workpiece in the prior art;

[0025] Figure 2 This is a schematic diagram of the injection molding process for a plastic workpiece according to this application;

[0026] Figure 3 This is a structural schematic diagram of a plastic workpiece according to this application;

[0027] Figure 4 This is a schematic diagram of the structure of a plastic workpiece injection-molded semi-finished product according to this application.

[0028] Numbering on the map:

[0029] 10. Injection-molded semi-finished product; 11. Nut; 12. Plastic part; 121. Connecting part; 122. Abutting part; 20. Injection-molded component; 30. First connecting ring; 40. Second connecting ring; X, length direction of nut; Y, width direction of nut. Detailed Implementation

[0030] To provide a clearer understanding of the technical features, objectives, and effects of this invention, specific embodiments are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the orientations or positional relationships indicated by terms such as "front," "rear," "upper," "lower," "left," "right," "longitudinal," "horizontal," "vertical," "horizontal," "top," "bottom," "inner," "outer," "head," and "tail" are based on the orientations or positional relationships shown in the accompanying drawings, and are constructed and operated in a specific orientation. They are only for the convenience of describing this technical solution and do not indicate that the device or element referred to must have a specific orientation; therefore, they should not be construed as limitations on this invention.

[0031] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0032] In related technologies, such as Figure 1 As shown, the current manufacturing process for plastic parts involves directly placing the nut 11 into the mold, then injecting plastic material along the length X of the nut 11. After the plastic material in the mold cools, it will coat the nut 11 with a layer of plastic. Because the nut 11 and the coated plastic have different cooling shrinkage rates, it is necessary to further fill the gap between the nut 11 and the coated plastic with plastic material to form the plastic part. However, during the filling process, the nut 11 is subjected to an impact force along the filling direction, causing it to move, resulting in defective plastic parts that cannot meet assembly requirements for subsequent use. In addition, to prevent the nut 11 from moving during the filling process, a positioning component is used to extend into the nut 11 to position it. However, if the inner diameter of the nut 11 is too small, it is easy to cause misalignment during assembly, making it impossible to install the nut 11 into the fixed position during positioning, ultimately resulting in a defective injection-molded plastic part. Therefore, to solve the above technical problems, this application proposes an injection molding process for plastic parts.

[0033] Specifically, such as Figure 2 As shown, the injection molding process for this plastic workpiece includes the following steps:

[0034] S100. Place the rubber-coated end of the nut 11 into the first mold and inject rubber into the first mold.

[0035] S200. After the rubber material in the first mold cools down, it forms the injection-molded semi-finished product 10.

[0036] S300: Remove the injection-molded semi-finished product 10 from the first mold, place the injection-molded semi-finished product into the second mold, and inject the rubber material into the second mold.

[0037] S400. After the material in the second mold cools to the preset time, an injection molded body is formed.

[0038] S500: Remove the injection molded body from the second mold to obtain the plastic workpiece.

[0039] For example, the "plastic-coated end" mentioned above refers to the end of the nut 11 that is wrapped in plastic. The specific definition can be based on the actual structure of the nut 11 and is not limited thereto.

[0040] For example, during the secondary injection molding of the nut 11, the end face of the injection-molded semi-finished product 10 is pressed by the second mold, and then rubber material is injected into the second mold so that the rubber material is wrapped around the injection-molded semi-finished product. After the rubber material cools, a plastic workpiece is formed. In addition, it should be noted that in the process of introducing rubber material into the first mold and the second mold, components commonly used in the prior art for injecting rubber material into molds can be used.

[0041] For example, during the placement of the nut 11 into the first and second molds, guide pins need to be installed within both molds to ensure that the nut 11 is inserted vertically and into the correct position, preventing tilting and product defects. It should be noted that since plastic is formed on the coated end of the nut before placement into the second mold and is used to fix it within the mold, the guide pins only serve a guiding function without needing to secure the nut. This effectively reduces the generation of metal shavings and damage to the threads within the nut 11. Furthermore, the nut in this embodiment is a copper nut.

[0042] The injection molding process for plastic parts based on the above-mentioned technical features involves first injecting plastic material into the overmolded end of the nut 11. After the material cools, it wraps around the overmolded end of the nut, forming an injection-molded semi-finished product 10. Then, the semi-finished product 10 is placed into a second mold, and more plastic material is injected. After the material cools, it wraps around the outside of the semi-finished product, thus obtaining the plastic part. Compared to the traditional one-time injection molding method, no additional fixing components are needed to secure the nut 11, ensuring that the nut 11 will not move due to impact during the injection process, thus improving product quality. Furthermore, because the plastic is formed at the overmolded end of the nut 11 first, during the second injection, the guide pins in the mold only serve a guiding function and will not rub against the inner hole of the nut 11, effectively preventing damage to the threads inside the nut 11.

[0043] In one embodiment, during the step of injecting the adhesive into the first mold, the adhesive is fed into the first mold along the width direction Y of the nut 11. In this way, the nut 11 is only subjected to the impact force in the width direction Y, reducing the impact force in the length direction X and ensuring the dimensional requirements of the subsequently formed plastic part. For example, if the adhesive is filled along the length direction X of the nut 11, the nut 11 will be subjected to the impact force in the length direction X, causing the overmolded end of the nut 11 to extend into the plastic part, making it impossible to guarantee the required processing dimension L.

[0044] In one embodiment, during the step of injecting the adhesive into the second mold, the adhesive is fed into the second mold along the length direction X of the nut 11. Thus, the nut 11 is only subjected to the impact force in the length direction X. Since the plastic part wrapped around the end of the nut 11 abuts against the mold, the nut will not move along the length direction X. Furthermore, since the width direction Y is not subjected to the impact force, tilting will not occur, ensuring the dimensional requirements of the subsequently formed plastic workpiece are met.

[0045] In one embodiment, the injection-molded semi-finished product 10 includes a nut 11 and a plastic part 12, the plastic part 12 being connected to the rubber-coated end of the nut 11; the plastic part 12 includes a connecting portion 121 and an abutting portion 122, the abutting portion 122 protruding from the surface of the connecting portion 121 away from the nut 11, and the connecting portion 121 forming a cavity for connecting with the rubber-coated end of the nut 11. During the step of placing the injection-molded semi-finished product 10 into the second mold, the surface of the abutting portion 122 abuts against the second mold.

[0046] For example, after the injection-molded semi-finished product 10 is placed into the second mold, the abutment portion 122 abuts against the mold so that the nut 11 will not move in the length direction X during the process of filling the material along the length direction X of the nut 11, thus ensuring the required processing dimensions.

[0047] In one embodiment, the diameter of the abutment portion 122 is smaller than the diameter of the connecting portion 121, and the center of the abutment portion 122 and the center of the connecting portion are on the same straight line. Specifically, the diameter of the abutment portion 122 is 2 / 3 to 3 / 4 of the diameter of the connecting portion 121. For example, setting the diameter of the abutment portion 122 within the aforementioned range allows the plastic part 12 to form a stepped shape, facilitating subsequent clamping with the second mold. This effectively prevents movement due to the impact force during material filling, ensuring the required processing dimensions of the product.

[0048] In one embodiment, the outer peripheral surface of the rubber-coated end of the nut 11 is provided with a first connecting ring 30, and the outer surface of the first connecting ring 30 is provided with threads. When the plastic part 12 is connected to the nut 11, the portion of the first connecting ring 30 extending into the cavity occupies 2 / 3 to 4 / 5 of the first connecting ring 30.

[0049] In one embodiment, a plurality of second connecting rings 40 are spaced apart on the outer circumferential surface of the nut 11, and the outer surface of the second connecting rings 40 is threaded. This increases the contact area between the plurality of second connecting rings 40 and the plastic part surrounding the nut 11, preventing the nut 11 from rotating inside the plastic part and ensuring that subsequent screws are properly screwed into the nut 11 for assembly.

[0050] Please refer to Figure 3 and Figure 4 This application also provides a plastic workpiece manufactured by injection molding process of the plastic workpiece of the above embodiment. The plastic workpiece includes a nut 11, a plastic part 12 and an injection molding component 20. The plastic part 12 is connected to the rubber-coated end of the nut 11, and the injection molding component 20 is provided with a receiving cavity for accommodating the plastic part 12 and the nut 11.

[0051] For example, nut 11 is made of copper. This makes the nut easier to machine.

[0052] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. An injection molding process for plastic workpieces, characterized in that, Includes the following steps: Place the rubber-coated end of the nut into the first mold and inject rubber into the first mold; After the rubber material in the first mold cools, it forms an injection-molded semi-finished product; The injection-molded semi-finished product is removed from the first mold and placed into the second mold, and then the rubber material is injected into the second mold. After the rubber material in the second mold cools to the preset time, an injection molded body is formed; The injection molded body is removed from the second mold to obtain a plastic workpiece; In the step of injecting adhesive into the first mold, the adhesive is fed into the first mold along the width direction of the nut; In the step of injecting the adhesive into the second mold, the adhesive is fed into the second mold along the length direction of the nut; The injection-molded semi-finished product includes a nut and a plastic part, the plastic part being connected to the rubber-coated end of the nut; the plastic part includes a connecting portion and an abutting portion, the abutting portion protruding from the surface of the connecting portion away from the nut, the connecting portion forming a cavity for connecting with the rubber-coated end of the nut; wherein, in the step of placing the injection-molded semi-finished product into the second mold, the surface of the abutting portion abuts against the second mold.

2. The injection molding process for plastic workpieces according to claim 1, characterized in that, The diameter of the abutting part is smaller than the diameter of the connecting part, and the center of the abutting part and the center of the connecting part are on the same straight line; The diameter of the abutting part is 2 / 3 to 3 / 4 of the diameter of the connecting part.

3. The injection molding process for plastic workpieces according to claim 1, characterized in that, The outer circumferential surface of the rubber-coated end of the nut is provided with a first connecting ring, and the outer surface of the first connecting ring is provided with threads; Wherein, when the plastic part is connected to the nut, the portion of the first connecting ring extending into the cavity occupies 2 / 3 to 4 / 5 of the first connecting ring.

4. The injection molding process for plastic workpieces according to claim 1, characterized in that, The outer circumferential surface of the nut is also provided with a plurality of second connecting rings at intervals, and the outer surface of the second connecting rings is provided with threads.

5. The injection molding process for plastic workpieces according to claim 1, characterized in that, The nut is a copper nut.

6. A plastic workpiece manufactured using the injection molding process according to any one of claims 1 to 5, characterized in that, The plastic workpiece includes a nut, a plastic part, and an injection-molded component. The plastic part is connected to the rubber-coated end of the nut, and the injection-molded component is provided with a receiving cavity for accommodating the plastic part and the nut.

7. The plastic workpiece according to claim 6, characterized in that, The nut is made of copper.

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