WO2023065482A1

WO2023065482A1 - Injection molding method

Info

Publication number: WO2023065482A1
Application number: PCT/CN2021/136620
Authority: WO
Inventors: 丘艾密; 秦永刚; 刘华祥; 丁志勇; 谢建君; 万高
Original assignee: 歌尔股份有限公司
Priority date: 2021-10-19
Filing date: 2021-12-09
Publication date: 2023-04-27
Also published as: CN114043666A; CN114043666B

Abstract

An injection molding method, comprising: providing a fixing device (10), an insert, and a mold (20), wherein a mold cavity is provided inside the mold (20), the fixing device (10) is located in the mold cavity, the fixing device (10) is provided with a bearing surface (16), the bearing surface (16) is used for bearing the insert, an air hole (14) is formed in the fixing device (10), the air hole (14) has a first opening (15) and a second opening, the first opening (15) is located on the bearing surface (16), the second opening is configured to be connected to a negative pressure device, and one end surface of the insert is opposite to the first opening (15); forming a negative pressure in the air hole (14); injecting an injection molding material into the mold cavity; and after injection molding is completed, separating an injection-molded product from the mold cavity and separating the insert from the bearing surface (16). The first opening (15) can form an adsorption force along the axial direction of the fixing device (10) to the insert to adsorb the insert on the bearing surface (16), so that the insert can be prevented from loosening or falling in the injection molding process.

Description

Injection method

technical field

Embodiments of the present disclosure relate to the technical field of injection molding, and more specifically, to an injection molding method.

Background technique

Injection molding When the shell of the product is provided with an embedded structure, it is usually injection molded after inserting the insert in the mold. It is usually necessary to fasten the Insert to the moving mold. However, the inserts of the mold are easy to drop during the mold clamping process.

In the prior art, taking the nut insert as an example, in order to prevent the nut from loosening or falling off during the mold clamping process. Using a threaded needle matched with the nut, after the threaded needle and the nut are tightened, the threaded needle and the nut are integrally embedded in the mold for injection molding. After the injection molding is completed, it is ejected together with the thread needle, and then the thread needle is reversely rotated from the product, and the thread needle is removed from the nut, so as to obtain a plastic product with a nut.

However, this method is inefficient and the process is complicated, and after injection molding, the thread needle needs to be reversely rotated to separate from the nut, which easily causes stress on the lagging around the nut, resulting in poor nut lagging.

Therefore, a new technical solution needs to be provided to solve the above technical problems.

Contents of the invention

An object of the present disclosure is to provide a new technical solution of the injection molding method.

In one embodiment of the present disclosure, an injection molding method is provided. Described injection molding method comprises:

Provide a fixing device, an insert and a mold, wherein a cavity is provided inside the mold, the fixing device is located in the cavity, the fixing device has a bearing surface, and the bearing surface is used to bear the An insert, an air hole is formed in the fixing device, the air hole has a first opening and a second opening, the first opening is located on the bearing surface, and the second opening is used for contacting with the negative The pressure device is connected, and one end surface of the insert is opposite to the first mouth;

forming a negative pressure in the air hole; injecting plastic into the cavity;

After injection molding is completed, the injection molded product is separated from the cavity and the insert is separated from the bearing surface.

Optionally, there are multiple air holes, and multiple first openings are formed on the bearing surface.

Optionally, the fixing device includes a sleeve and a thimble, a cavity is formed in the middle of the sleeve, the thimble is located in the cavity, and an end surface of the sleeve surrounding the thimble forms a The bearing surface, the sleeve is formed with the air hole, and after the injection molding is completed, the thimble protrudes along the axial direction of the sleeve, so as to separate the injection molded product from the cavity and separate the molded product. The insert is separated from the bearing surface.

Optionally, the insert is a nut, and the nut has a screw hole, and the thimble extends into the screw hole.

Optionally, the sleeve has a side surface connected to the bearing surface, a communication cavity is provided in the sleeve, the second mouths of the plurality of air holes communicate with the communication cavity, and A third port is formed on the side surface, and the third port communicates with the communication cavity.

Optionally, the communication cavity is formed by electric spark discharge.

Optionally, the communication cavity is arranged around the thimble.

Optionally, the communication cavity communicates with the cavity.

Optionally, an axially extending groove is formed on one side of the fixing device close to the cavity, and the outer wall of the thimble and the groove jointly enclose the air hole.

Optionally, the inner diameter of the pores is 0.8mm-1.5mm.

Air holes are provided on the fixing device, and a negative pressure is formed in the air holes, so that the first mouth can form an adsorption force on the insert along the axial direction of the fixing device to adsorb the insert on the bearing surface. In this way, it is possible to avoid loosening or falling of the insert during the injection molding process.

Other features of the present specification and advantages thereof will become apparent through the following detailed description of exemplary embodiments of the present specification with reference to the accompanying drawings.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate the embodiments of the specification and together with the description serve to explain the principles of the specification.

Fig. 1 is the flowchart of an embodiment of the injection molding method of the present disclosure;

Fig. 2 is the flowchart of an embodiment of the injection molding method of the present disclosure;

Fig. 3 is a structural schematic diagram of an embodiment of the fixing device of the present disclosure;

Fig. 4 (a) is one of the top views of Fig. 3;

Fig. 4 (b) is the second top view of Fig. 3;

Fig. 5 is a partial structural schematic diagram of an embodiment of the mold of the present disclosure;

Fig. 6 is a partially enlarged view of part A in Fig. 5;

FIG. 7 is a schematic diagram of the formation of the communication cavity in the embodiment of the present disclosure.

Explanation of reference signs:

10. Fixing device; 11. Sleeve; 12. Thimble; 13. First through hole; 14. Air hole; 15. First mouth; 16. Bearing surface; 17. Nut; 18. Connecting cavity; 19. Third Mouth; 20, mould; 21, moving mold; 22, steel needle; 23, electrode.

Detailed ways

Embodiments of the present disclosure will be described in detail below, examples of which are illustrated in the drawings, in which the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the figures are exemplary only for explaining the present disclosure and should not be construed as limiting the present disclosure. Based on the embodiments in the present disclosure, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present disclosure.

Techniques, methods and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such techniques, methods and devices should be considered part of the description.

The features of the terms "first" and "second" in the description and claims of the present disclosure may explicitly or implicitly include one or more of these features. In the description of the present disclosure, unless otherwise specified, "plurality" means two or more.

In describing the present disclosure, it is to be understood that the terms "center", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", " Right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "circumferential", etc. The orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present disclosure and simplifying the description, and does not indicate or imply that the referred device or element must have a specific orientation, be configured in a specific orientation, and operation, and therefore should not be construed as limiting the present disclosure.

In the description of the present disclosure, it should be noted that the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be A mechanical connection can also be an electrical connection; it can be a direct connection or an indirect connection through an intermediary, and it can be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present disclosure in specific situations.

According to one embodiment of the present disclosure, an injection molding method is provided. Referring to FIG. 1 , the injection molding method includes providing a fixture 10 , an insert and a mold 20 . Wherein, a cavity is provided inside the mold 20 . The fixture 10 is located within the cavity. The fastening device 10 has a support surface 16 . The carrying surface 16 serves to carry the insert. An air hole 14 is formed in the fixing device 10 . The air hole 14 has a first mouth 15 and a second mouth. The first mouth 15 is located on the bearing surface 16 . The second port is used to connect with the negative pressure device. One end face of the insert is opposite the first mouth 15 .

A negative pressure is created in the air holes 14 .

Inject plastic into the cavity.

After injection molding is complete, the injection molded product is separated from the cavity and the insert is separated from the bearing surface 16 .

The carrying surface 16 serves to carry the insert. For example, the insert can be a nut 17, a bushing or a bushing.

When a negative pressure is formed in the air hole 14 , the first mouth portion 15 forms a negative pressure on the bearing surface 16 . In this way, the insert placed on the bearing surface 16 can be adsorbed on the bearing surface 16 to avoid loosening or falling of the insert during the injection molding process.

Furthermore, the insert can be more easily separated from the fixing device 10 after injection moulding. In this way, it is possible to avoid acting on the rubber lagging around the insert of the injection molded product, and to avoid the technical problem of poor rubber lagging.

The cavity is an integral cavity or a split cavity. Integral mold cavity, that is, a concave mold cavity in which the mold cavity is surrounded by a whole mold 20 .

Optionally, the mold cavity is a combined mold cavity, for example, the mold 20 includes multiple parts, and the multiple parts are spliced to form a combined mold cavity.

The fixing device 10 is a device capable of setting and holding the insert at a predetermined position in the cavity. For example, a cylinder pin, a guide post or a guide sleeve, etc.

Negative pressure is formed in the air hole 14, and then injection plastic is injected into the cavity. In this way, it is possible to avoid loosening or falling of the insert when the cavity is displaced.

Optionally, a negative pressure can be formed in the air hole 14 while injecting the injection material.

After negative pressure is formed in the air hole 14 , the injection molded part is adsorbed on the bearing surface 16 . The projection range of the injection molded part covers the projection range of the first air hole 14 . In this way, when the insert is wrapped with plastic to form the rubber covering part, the stress of the rubber covering part on the insert is avoided, which may lead to misalignment of the insert.

After the injection molding is completed, the injection molded product is separated from the cavity, and the insert is separated from the bearing surface 16 . It may be that when the insert is separated from the bearing surface 16, the air hole 14 still maintains a negative pressure state.

It is also possible that when the insert is separated from the bearing surface 16 , the inside of the air hole 14 maintains a normal pressure state.

In one embodiment, as shown in FIG. 4( a ) or FIG. 4( b ), there are multiple air holes 14 . A plurality of first openings 15 are formed on the carrying surface 16 . In this way, the insert is more firmly adsorbed on the surface of the bearing surface 16 .

In one embodiment, referring to FIG. 3 and FIG. 4( a ), the fixing device 10 includes a sleeve 11 and a thimble 12 , and a cavity is formed in the middle of the sleeve 11 . The thimble 12 is located in the cavity, and an end surface of the sleeve 11 surrounding the thimble 12 forms a bearing surface 16 . The sleeve 11 is formed with air holes 14 . After the injection molding is completed, the thimble 12 protrudes along the axial direction of the sleeve 11 to separate the injection molded product from the cavity and the insert from the bearing surface 16 .

The ejector pin 12 can move up and down in the cavity of the sleeve 11 along the axial direction of the sleeve 11 to push the injection molded product out of the injection molding material.

In other embodiments, the fixing device 10 only includes a fixing base, and the fixing base has a bearing surface 16 for bearing the insert. An air hole 14 is formed on the side wall of the fixing seat, and the air hole 14 includes a first opening 15 and a second opening 16 . The first mouth 15 is located on the bearing surface 16 , and the second mouth is connected with a negative pressure device to form a negative pressure in the air hole 14 , so that the insert is adsorbed on the bearing surface 16 .

Wherein, the thimble 12 can be used to separate the insert from the fixing device 10 after the injection molding is completed.

Specifically, referring to FIG. 2, after the injection molding is completed, the steps of separating the injection molded product from the cavity and separating the insert from the bearing surface 16 include:

After the injection molding is completed, the thimble 12 protrudes along the axial direction of the sleeve 11 to separate the injection molded product from the cavity and the insert from the bearing surface 16 .

When the thimble 12 moves up and down along the axial direction of the sleeve 11 in the cavity of the sleeve 11, a part of the thimble 12 can stretch out from the cavity to protrude from the bearing surface 16. That is, the end surface of the thimble 12 in contact with the injection molded product can protrude outward to protrude from the bearing surface 16 , and can also be retracted into the cavity.

When separating the insert from the bearing surface 16 , the ejector pin 12 protrudes from the cavity and protrudes from the bearing surface 16 until it contacts the surface of the injection molded product. Continue to apply force to the thimble 12, so that the thimble 12 continues to protrude outward. Until the bearing surface 16 is separated from the insert inserted into the injection molded product.

In this way, after injection molding, the insert can be easily separated from the fixing device 10, avoiding stress on the lagging around the insert in the injection molded product to avoid damage or poor lagging of the insert in the injection molded product The problem.

There are a plurality of air holes 14 , and a plurality of first openings 15 are formed on the bearing surface 16 .

For example, referring to FIG. 4 , a plurality of first mouth portions 15 are evenly distributed along the sleeve 11 around the thimble 12 . In this way, the negative pressure on the end surface of the insert in contact with the bearing surface 16 is more balanced. Can improve the consistency of injection molding. It is also possible to more firmly adsorb the insert on the surface of the carrying surface 16 .

For example, referring to FIG. 4 , there are four air holes 14 , and the four air holes 14 form four first openings 15 on the bearing surface 16 . The four first mouths 15 are evenly distributed around the thimble 12 .

For example, there are six air holes 14 , and the six air holes 14 form six first openings 15 on the bearing surface 16 . Six first mouths 15 are distributed circularly around the cavity. In this way, the fixing effect on the insert is further improved.

The number of air holes 14 is not limited to the above embodiments, and those skilled in the art can set them according to actual needs.

The air hole 14 may communicate with the cavity or be arranged at a distance from the cavity.

For example, the air hole 14 may be located in the side wall of the sleeve 11, the air hole 14 is located between the inner wall and the outer wall of the sleeve 11, and is separated from the cavity.

Specifically, the method for forming air hole 14 is:

A sleeve 11 is prepared, and a cavity is formed in the middle of the sleeve 11 .

As shown in Figure 4(b), from the bearing surface 16 of the sleeve 11, a hole is drilled downwards along the axial direction of the sleeve 11, and a hole parallel to the central axis of the cavity is formed at a position between the inner wall and the outer wall of the sleeve 11. The first through hole 13 is a part of the air hole 14 .

At the position where the outer wall of the sleeve 11 corresponds to the first through hole 13, from the outer wall of the sleeve 11 along the radial direction of the sleeve 11, a second hole perpendicular to the central axis of the first through hole 13 is formed. The through hole is to communicate with the first through hole 13 and the second through hole, and the second through hole is another part of the air hole 14. After the first through hole is communicated with the second through hole, the air hole 14 is formed, and the second through hole is in the sleeve A second mouth is formed on the outer wall of 11.

Those skilled in the art can understand that the pores 14 can also be formed by other methods, such as grinding, cutting, or extrusion.

Air holes 14 may also be provided on the inner wall of the sleeve 11 and communicate with the cavity.

For example, an axially extending groove is formed on the side of the sleeve 11 close to the cavity. The outer surface of the thimble 12 and the groove together form an air hole 14 .

Specifically, the groove can be formed by cutting. The cutting knife enters the cavity from one end of the cavity, and the cutting edge contacts the side wall of the cavity and forms a groove at a set position of the side wall of the cavity.

The groove runs through the inner wall of the sleeve 11 in the axial direction and is parallel to the central axis of the cavity.

The thimble 12 is placed in the cavity, so that the outer surface of the thimble 12 and the inner wall of the sleeve 11 together form an air hole 14 .

In the above examples, the first mouth 15 is located on the carrying surface 16 , and the cross-sectional shape of the first mouth 15 is a circle, a rectangle, or the like. No specific limitation is imposed on the cross-sectional shape of the first mouth portion 15 here.

The second port is used to connect with the negative pressure device. Turn on the negative pressure device to form a negative pressure in the air hole 14 so that the first mouth 15 can adsorb the insert on the bearing surface 16 .

The second mouth is connected to the negative pressure device, and may also be connected to the negative pressure device through other structures.

In one example, the inner diameter of the air hole 14 is 0.8mm-1.5mm. Within this range, the structure of the sleeve 11 is more stable while the air hole 14 satisfies the adsorption force on the insert.

In one embodiment, the insert is a nut 17 , the surface of one end of the nut 17 is opposite to the first mouth 15 , and the thimble 12 is located in the screw hole of the nut 17 .

The thimble 12 is located in the screw hole, on the one hand, it plays a role of occupying space, and prevents the thread structure of the inner wall of the nut 17 and the through hole inside the nut 17 from being filled with injection molding material. On the other hand, the nut 17 can also be further fixed to prevent the nut 17 from being displaced when the orientation of the cavity changes.

In one embodiment, referring to FIG. 3 , the sleeve 11 has a side surface connected to the bearing surface 16 . A communication cavity 18 is provided in the sleeve 11 . The second mouths of the plurality of air holes 14 communicate with the communication cavity 18 . A third mouth portion 19 is formed on the side surface. The third port 19 communicates with the communication cavity 18 .

A plurality of air holes 14 are arranged parallel to each other and parallel to the central axis of the cavity.

The second mouth is located in the side wall and isolated from the outside. A plurality of second mouths are all communicated with the communication chamber 18, and a third mouth 19 is formed on the side surface of the sleeve 11, the third mouth 19 is communicated with the communication chamber 18, and the third mouth 19 is connected with the negative pressure device to Negative pressure is realized in the communication chamber 18 to form a negative pressure in the air hole 14 through the second opening to adsorb the insert on the bearing surface 16 .

The number of the third mouth 19 may be one or more. That is, when there is one communicating chamber 18, one third mouth 19 can be formed on the outer wall to communicate with the communicating chamber 18, or a plurality of third mouths 19 can be formed on the outer wall, and the plurality of third mouths 19 are all connected to the communicating chamber. 18 connected.

Optionally, when there are multiple third openings 19 , they may be evenly distributed around the side wall of the sleeve 11 . Optionally, when there are multiple third ports 19, they can be connected to multiple negative pressure devices.

The communication cavity 18 is arranged perpendicular to the central axis of the air hole 14 .

For example, referring to FIG. 3 , the communication chamber 18 communicates with the cavity.

The communication cavity 18 is located on the inner wall of the sleeve 11 , and the outer wall of the thimble 12 and the inner wall of the sleeve 11 together form the communication cavity 18 .

In one embodiment, the communication cavity 18 is formed by electric spark discharge.

Specifically, the formation method of the communication chamber 18 is as follows:

A steel needle 22 is provided, an electrode 23 matching the set shape of the communication cavity 18 is provided, and the steel needle 22 is connected with the electrode 23 to form an electrode assembly.

Put the electrode assembly into the cavity from the mouth where the bearing surface 16 of the sleeve 11 is located, and place it at a set position in the cavity.

Put the electrode assembly and the fixing device 10 in the insulating liquid.

The electrode assembly is connected with a spark machine, and the spark machine applies a set voltage to the electrode assembly to form a communication cavity 18 communicating with the air hole 14 .

Wherein, the diameter of the electrode assembly is smaller than the diameter of the cavity. For example, the diameter of the cavity is 1mm, and the diameter of the electrode assembly can be between 0.1mm-0.5mm. Preferably, the diameter of the electrode assembly is 0.4mm.

In this way, when the size of the cavity is small and the thickness of the side wall of the sleeve 11 is relatively thin, the communication cavity 18 can be processed on the cavity wall of the cavity.

Optionally, the electrodes are cylindrical or arcuate.

Optionally, the electrodes are copper or copper alloy.

Optionally, the cross section of the electrode is circular, quadrangular, etc.

In one example, referring to FIG. 3 or FIG. 4 , the communication cavity 18 is disposed around the thimble 12 .

For example, there is one communication cavity 18 , and the communication cavity 18 surrounds the thimble 12 and is along the side wall of the sleeve 11 . The cross-sectional shape of the communication cavity 18 is arc or ring.

For example, there are multiple communicating cavities 18 . The plurality of communication cavities 18 are correspondingly connected to the set second ports. A third port 19 is formed on the outer wall of the sleeve 11 to communicate with the corresponding communication cavity 18 .

In this way, in the set state, the set third ports 19 can be respectively connected to the negative pressure device to form negative pressure in the set first port 15 .

In one embodiment, the mold 20 includes a movable mold part 21 and a static mold part. Referring to FIG. 5 and FIG. 6 , one end of the fixing device 10 is fixed on the movable mold part 21 . The nut 17 is sheathed on the thimble 12 and is located at the end of the fixing device 10 opposite to the movable mold part 21 .

Negative pressure is formed in the air hole 14 so that the first mouth portion 15 can be fixed on the bearing surface 16 such as a nut 17 . Then the movable mold part 21 is moved and clamped with the static mold part to form a mold cavity.

While injecting plastic into the mold cavity, keep the first mouth portion 15 to provide negative pressure to the nut 17 so as to adsorb the nut 17 on the bearing surface 16 .

After the injection molding is completed, the fixing device 10 is separated from the nut 17 .

In this way, it is possible to prevent the nut 17 from loosening or falling off when the movable mold part 21 is displaced or when the position is changed. At the same time, it is effectively avoided that when the fixing device 10 is separated from the nut 17 , the rubber lagging at the position of the nut 17 in the injection molded product is damaged.

The description of "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific examples", or "some examples" means specific features, structures described in connection with the embodiment or example , material or characteristic is included in at least one embodiment or example of the present disclosure. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While the embodiments of the present disclosure have been shown and described. Those skilled in the art can understand that various changes, modifications, substitutions and modifications can be made to these embodiments without departing from the principle and purpose of the present disclosure. The scope of the present disclosure is defined by the claims and their equivalents.

Claims

A kind of injection molding method, is characterized in that, comprises:

Provide a fixing device, an insert and a mold, wherein a cavity is provided inside the mold, the fixing device is located in the cavity, the fixing device has a bearing surface, and the bearing surface is used to bear the An insert, an air hole is formed in the fixing device, the air hole has a first opening and a second opening, the first opening is located on the bearing surface, and the second opening is used for contacting with the negative The pressure device is connected, and one end surface of the insert is opposite to the first mouth;

creating a negative pressure within said stomata;

Inject injection plastic into the cavity;

After injection molding is completed, the injection molded product is separated from the cavity and the insert is separated from the bearing surface.
The injection molding method according to claim 1, characterized in that there are multiple air holes, and multiple first openings are formed on the bearing surface.
The injection molding method according to claim 2, wherein the fixing device comprises a sleeve and a thimble, a cavity is formed in the middle of the sleeve, and the thimble is located in the cavity, surrounding the One end surface of the sleeve of the thimble constitutes the bearing surface, and the sleeve is formed with the air hole. After the injection molding is completed, the thimble protrudes along the axial direction of the sleeve, so that the injection molded product separating from the cavity and separating the insert from the load-bearing surface.
The injection molding method according to claim 3, wherein the insert is a nut, the nut has a screw hole, and the ejector pin extends into the screw hole.
The injection molding method according to claim 3, characterized in that, the sleeve has a side surface connected to the bearing surface, a communicating cavity is provided in the sleeve, and the second of the plurality of air holes The mouth communicates with the communication chamber, and a third mouth is formed on the side surface, and the third mouth communicates with the communication chamber.
The injection molding method according to claim 5, wherein the communication cavity is formed by electric spark discharge.
The injection molding method according to claim 5, wherein the communication cavity is arranged around the ejector pin.
The injection molding method according to claim 7, characterized in that, the communication cavity communicates with the cavity.
The injection molding method according to claim 3, wherein an axially extending groove is formed on the side of the fixing device close to the cavity, and the outer wall of the thimble and the groove jointly form a the stomata.
The injection molding method according to any one of claims 1-9, characterized in that the inner diameter of the pores is 0.8mm-1.5mm.