Demolding process, injection molding process and injection mold for injection molding part with complex surface

Abstract

The invention discloses a demolding process, an injection molding process and an injection mold for a complex-surface injection molded part, the demolding process is suitable for separation of the injection mold with a flexible cavity and the injection molded part, the flexible cavity comprises at least one convex area and a concave area corresponding to the convex area, the convex area is used for forming the concave outer contour of the injection molded part, and the concave area is used for forming the concave outer contour of the injection molded part. The demolding process comprises the following steps that B1, the convex area moves in the direction away from the injection molding part, and a gap is formed between the convex area and the injection molding part; and B2, the concave area is made to protrude out towards the side close to the injection molding part, the injection molding part is ejected out, and separation of the injection molding part and the injection mold is achieved. According to the flexible mold, the problems of jamming, extrusion and even structural damage occurring in complex concave areas such as earphone hanging lugs in the demolding process of a traditional flexible mold are effectively solved.

Description

Technical Field

[0001] The present application relates to the field of injection molding, and in particular to a demoulding process, an injection molding process, and an injection mold for injection molded parts with complex surfaces. Background Art

[0002] Injection molding technology offers the advantages of high production efficiency, low cost, and consistent molding quality, making it suitable for mass production of plastic parts. Consequently, it is widely used in consumer electronics, automotive components, medical devices, and other fields. The traditional injection molding process generally involves closing the mold, injecting molten polymer into the mold cavity, cooling and solidifying, opening the mold, and demolding the molded part. This allows for the rapid production of plastic parts with a defined profile and surface quality.

[0003] During the demolding process of injection molded parts with complex surfaces, due to the complex interface between the part and the mold cavity, there is greater resistance compared to the demolding of simple injection molded parts with smooth surfaces. This resistance is often difficult to achieve by relying solely on the weight of the part itself. To better facilitate the demolding of parts with complex structures, flexible molds are gaining widespread application in the injection molding field. By using a flexible bladder structure as part of the mold cavity wall, the surface of the bladder expands toward the molded part during demolding, generating thrust between the part and the mold, effectively reducing demolding resistance. This makes flexible molds suitable for demolding parts with complex contours.

[0004] However, existing flexible mold demolding technology still has shortcomings in certain application scenarios. In the concave areas of some complex injection molded parts, such as the ear hook depression of headphones, when the internal pressure of the flexible mold increases and the cavity surface expands, the protruding cavity surface in this area will instead get stuck in the concave area of ​​the injection molded part during the demolding process, thereby squeezing the injection molded part. Not only can it not be smoothly demolded, it is also likely to cause permanent deformation or even structural damage to the injection molded part. Therefore, there is an urgent need for a flexible mold and demolding process optimized for complex surface injection molded parts to solve the problem of deformation or damage to complex structure injection molded parts during the demolding process. Summary of the Invention

[0005] One purpose of the present application is to provide a demolding process, an injection molding process and an injection mold for complex surface injection molded parts, which aims to solve the technical problem that complex surface injection molded parts such as earphones have recessed areas that are difficult to demold.

[0006] To achieve the above-mentioned objectives, in the first aspect, the present invention provides a demolding process for complex surface injection-molded parts, which is suitable for separating an injection mold having a flexible cavity from an injection-molded part. The flexible cavity includes at least one convex area and a concave area corresponding to the convex area. The convex area is used to form the concave outer contour of the injection-molded part, and the concave area is used to form the remaining outer contours of the injection-molded part. The demolding process includes the following steps: B1, moving the convex area away from the injection-molded part and creating a gap with the injection-molded part; B2, making the concave area bulge toward the side close to the injection-molded part and ejecting the injection-molded part to achieve separation of the injection-molded part from the injection mold.

[0007] According to one embodiment of the present invention, the injection mold includes a flexible bladder, and the bladder wall of the flexible bladder forms at least a portion of the mold cavity; step B1 includes: reducing the internal pressure of the flexible bladder, so that the convex area moves away from the injection molded part and creates a gap with the injection molded part; step B2 includes: increasing the internal pressure of the flexible bladder, so that the concave area bulges toward the side close to the injection molded part, and ejects the injection molded part, thereby achieving separation of the injection molded part from the injection mold.

[0008] According to one embodiment of the present invention, the flexible bag is filled with cooling liquid, and the pressure inside the flexible bag is increased or decreased by injecting or withdrawing the cooling liquid.

[0009] According to one embodiment of the present invention, the injection molded part is an earphone housing, and the convex area corresponds to the ear hook concave area of ​​the earphone housing.

[0010] In a second aspect, the present invention further provides an injection molding process for complex surface injection molded parts, wherein the injection molding process uses the demoulding process of the above embodiment to demould the injection molded parts.

[0011] In a third aspect, the present invention also provides an injection mold for complex surface injection molded parts, the injection mold comprising a concave mold and a convex mold, the two being fastened together to form a cavity, the concave mold comprising a concave area and a convex area, the concave mold being used to perform the demolding process of the above embodiment.

[0012] According to one embodiment of the present invention, the die includes a flexible bladder having a pressure regulating port for controlling the internal pressure of the flexible bladder, and a portion of the outer wall of the flexible bladder constitutes a convex area and at least a portion of a concave area.

[0013] According to one embodiment of the present invention, the flexible bag includes a first flexible bag and a second flexible bag, the pressure regulating port includes a first pressure regulating port and a second pressure regulating port respectively connected to the first flexible bag and the second flexible bag, part of the outer wall of the first flexible bag corresponds to the convex area, and part of the outer wall of the second flexible bag corresponds to at least part of the concave area.

[0014] According to one embodiment of the present invention, the flexible bladder further comprises an envelope sleeve, which covers the first flexible bladder and the second flexible bladder, and an outer surface of the envelope sleeve forms a partial cavity.

[0015] According to one embodiment of the present application, the injection mold of the complex surface injection molded part further comprises a liquid pump in communication with the flexible bladder for inputting or extracting the cooling liquid into the flexible bladder to adjust the pressure in the flexible bladder.

[0016] The present application has the following advantages: The demolding process provided by the present application sets convex regions and concave regions on the cavity wall surface of the flexible mold, the convex regions correspond to the outer contour of the recessed region of the injection molded part, and the concave regions correspond to the remaining outer contour of the injection molded part. In the demolding process, the convex regions are first moved away from the injection molded part, so that a certain gap is generated between the convex regions and the recessed surface of the injection molded part, so that the convex regions are no longer embedded in the recessed region of the injection molded part; then the concave regions of the cavity are bulged towards the injection molded part, and the bulging of the concave regions of the cavity pushes the injection molded part and the mold apart, thereby realizing stable demolding of the complex surface injection molded part.

[0017] Compared with the prior art, the demolding process provided by the present application uses the controllable deformation of the cavity surface of the flexible mold to specifically solve the problem of difficult demolding of complex surface injection molded parts. In the demolding process, the convex regions of the cavity corresponding to the recessed region of the injection molded part are retracted in advance to avoid direct expansion and extrusion of the convex regions on the recessed structure of the injection molded part, effectively avoiding the problems of jamming, extrusion and even structural damage in the complex recessed region such as the ear of the earphone in the demolding process of the traditional flexible mold, significantly improving the success rate of demolding of the complex surface injection molded part and the appearance quality of the product, and being suitable for more complex product structure design and production demand of high-quality products. BRIEF DESCRIPTION OF DRAWINGS

[0018] 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 or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0019] Figure 1 is a flowchart of the demolding process of the complex surface injection molded part provided by the embodiments of the present application; Figure 2 is a flowchart of the injection molding process of the complex surface injection molded part provided by the embodiments of the present application; Figure 3 is a structural diagram of the injection mold of the complex surface injection molded part provided by the embodiments of the present application.

[0020] Explanation of reference numerals: 1, cavity; 11, convex region; 12, concave region; 2, injection molded part; 21, injection molded melt; 3, flexible bladder; 31, first flexible bladder; 32, second flexible bladder; 4, cooling liquid; 5, convex mold; 6, concave mold; 7, envelope sleeve. DETAILED DESCRIPTION

[0021] The embodiments of the present application will be further described in conjunction with the drawings and examples. The detailed description of the following examples and drawings are used to exemplarily illustrate the principles of the present application, but cannot be used to limit the scope of the present application, i.e., the present application is not limited to the described examples.

[0022] The injection molding technology is widely used in mass production of plastic parts due to its high efficiency, low cost and stable quality. The flexible mold is suitable for plastic parts with complex shape by the pushing force generated by the movable cavity when demolding. However, the flexible mold may cause the plastic part to be stuck or damaged in some complex areas such as the earphone ear hook. Therefore, it is necessary to improve the flexible mold and demolding process to avoid the deformation or damage of the plastic part with complex structure during demolding.

[0023] Referring to Figure 1 as shown, Figure 1 is a flowchart of a demolding process of a complex surface injection molded part provided by the embodiments of the present application.

[0024] To solve the above technical problems, in a first aspect, the present application provides a demolding process of a complex surface injection molded part, which is suitable for the separation of an injection molded part 2 and an injection mold with a flexible cavity 1. The flexible cavity 1 includes at least one convex region 11 and a concave region 12 corresponding to the convex region 11. The convex region 11 is used to form the recessed outer contour of the injection molded part 2, and the concave region 12 is used to form the remaining outer contour of the injection molded part 2. The demolding process includes the following steps: B1, moving the convex region 11 away from the injection molded part 2 and generating a gap with the injection molded part 2; B2, bulging the concave region 12 towards the side of the injection molded part 2 and ejecting the injection molded part 2 to realize the separation of the injection molded part 2 and the injection mold.

[0025] The demolding process of the complex surface injection molded part provided by the embodiments of the present application first controls the internal pressure of the flexible cavity 1 to move the convex region 11 away from the injection molded part 2, so as to generate a certain gap between the convex region 11 and the recessed region of the injection molded part 2, thereby avoiding the convex region 11 from being embedded in the recessed structure of the injection molded part 2. Then, the internal pressure of the flexible cavity 1 is increased to bulge the concave region 12 towards the side of the injection molded part 2, thereby pushing the injection molded part 2 to separate from the mold cavity 1.

[0026] It should be noted that, in step B1 of this embodiment, “moving the convex area 11 in a direction away from the injection molded part 2 and forming a gap with the injection molded part 2” means controlling the convex area 11 and the concave area 12 separately so that only the convex area 11 moves in a direction away from the injection molded part 2; or the convex area 11 and the concave area 12 are not independently controlled, and in step B1, both the convex area 11 and the concave area 12 have a tendency to move in a direction away from the injection molded part 2, and a gap is formed between the convex area 11 and the concave area of ​​the injection molded part 2. Similarly, the "making the concave area 12 bulge toward the side close to the injection molded part 2" referred to in step B2 of this embodiment can be to control the convex area 11 and the concave area 12 separately so that only the concave area 12 bulges toward the direction close to the injection molded part 2; or the convex area 11 and the concave area 12 are not independently controlled. In step B2, even if the convex area 11 and the concave area 12 bulge toward the direction close to the injection molded part 2 at the same time, or even if the convex area 11 is embedded in the concave structure of the injection molded part 2 for a second time, since there will be no wetting phenomenon in the injection molding process when the cavity 1 and the injection molded part 2 are fitted again, the risk of the convex area 11 being stuck by the concave structure of the injection molded part 2 is also significantly reduced, and the injection molded part 2 is ejected together by the concave area 12 and the convex area 11 to achieve demolding.

[0027] Compared to the prior art, the demolding process of this application changes the strategy of simultaneously expanding the entire cavity 1 wall during demolding of conventional flexible molds, thus avoiding the jamming and squeezing caused by the convex area 11 of the cavity 1 being embedded in the concave area of ​​the injection molded part 2 during expansion. By first retracting the convex area 11, it is freed from the concave structure of the injection molded part 2 in advance, and then the expansion force of the concave area 12 is utilized to smoothly achieve demolding. This effectively avoids the problem of the injection molded part 2 being permanently deformed or even damaged due to the concave structure being stuck in the cavity 1 during the demolding process, significantly improving the demolding success rate and product quality of complex structure injection molded parts 2.

[0028] It should be understood that in the injection molding process of plastic parts, multiple molds are typically used. Multiple molds are combined, injection molded, opened, and demolded to obtain the molded part 2. Each mold may have convex areas 11 and concave areas 12. This embodiment only discusses the implementation principle of a single mold during the demolding process. In fact, in most injection molding processes, after mold opening, the mold to which the solidified molded part 2 is attached is predictable. In industrial production, performing the improvements of this embodiment on one mold in a complete set of molds to which the molded part 2 is attached can achieve a better flexible demolding effect.

[0029] According to one embodiment of the present invention, the injection mold includes a flexible bladder 3, and the bladder wall of the flexible bladder 3 forms at least a part of the cavity 1; step B1 includes: reducing the internal pressure of the flexible bladder 3, so that the convex area 11 moves away from the injection molded part 2 and creates a gap with the injection molded part 2; step B2 includes: increasing the internal pressure of the flexible bladder 3, so that the concave area 12 bulges toward the side close to the injection molded part 2, and ejects the injection molded part 2, thereby realizing the separation of the injection molded part 2 from the injection mold.

[0030] The embodiment provides a specific implementation of a flexible cavity 1 of an injection mold, that is, the shape change of the cavity 1 in the demolding process is realized by controlling the pressure change in the flexible bag 3. When the pressure in the flexible bag 3 decreases, due to the elasticity of the flexible bag 3 itself and the pressure difference caused by the decrease of the internal pressure, the bag wall of the flexible bag 3 is retracted to the inside of the bag body, thereby causing the convex area 11 on the surface of the cavity 1 to move away from the injection molded part 2, and as a result, a gap is formed between the convex area 11 of the injection mold and the concave area of the injection molded part 2; then, when the pressure in the flexible bag 3 increases again, the bag wall expands outward, causing the concave area 12 of the cavity 1 to protrude and expand towards the injection molded part 2, thereby pushing the injection molded part 2 away from the cavity 1.

[0031] The embodiment realizes the two stages of pre-retraction of the convex area 11 and expansion ejection of the concave area 12 by the first decrease and then increase of the pressure in the flexible bag 3, effectively avoiding the phenomenon that the convex area 11 is embedded in the concave area of the injection molded part 2 and causes jamming when the flexible cavity 1 expands as a whole in the prior art. Specifically, when the pressure in the bag decreases, the convex area 11 actively retracts, effectively avoiding the forced contact between the convex area 11 and the concave structure of the injection molded part 2 in the initial demolding stage, and preventing the damage of the injection molded part 2 in the concave area; then, the pressure in the bag is increased again, and the convex area 12 is expanded to smoothly realize the ejection demolding of the injection molded part 2. The embodiment does not need complex mechanical structures, and only by controlling the pressure in the flexible bag 3, the demolding success rate of the injection molded part with a complex surface and the appearance quality of the product can be effectively improved, and the embodiment has good industrial implementability and economy.

[0032] It should be understood that the flexible bag 3 can form independent pressure control cavities for the convex area 11 and the concave area 12, or the bag bodies corresponding to the convex area 11 and the concave area 12 can be interconnected. In the latter case, although the pressure changes of the convex area 11 and the concave area 12 always tend to be consistent, due to the different geometric structures of the convex area 11 and the concave area 12, when the pressure in the flexible bag 3 decreases, the convex area 11 will more obviously retract away from the injection molded part 2 due to the characteristics of its structural shape, thereby forming a clear gap with the concave area of the injection molded part 2; and when the pressure in the flexible bag 3 increases, although the convex area 11 may also expand to the position close to the injection molded part 2 together with the concave area 12, due to the gap formed previously and the close contact and infiltration effect no longer existing in the demolding process during the injection filling stage, the risk of the convex area 11 embedding into the concave area of the injection molded part 2 again is obviously reduced. Therefore, whether the flexible bag 3 controls the convex area 11 and the concave area 12 independently or not, it can effectively realize the demolding process of the embodiment, and will not have too much impact on the demolding effect.

[0033] Further, the flexible bag 3 is filled with cooling liquid 4, and the increase or decrease of the pressure in the flexible bag 3 is realized by injecting or extracting the cooling liquid 4.

[0034] In this embodiment, the flexible bag 3 is filled with cooling liquid 4, and during the injection molding process, the cooling liquid 4 filled in the flexible bag 3 can more quickly and uniformly absorb the heat released by the injection melt 21, thereby effectively reducing the cooling time of the injection molded part 2 and improving the cooling efficiency. From the perspective of flexible demolding process, due to the change of the shape of the injection cavity 1, it is difficult to avoid uneven extrusion stress on the injection molded part 2. Compared with the traditional gravity demolding of the fixed mold, the solidification effect of the flexible demolding on the injection molded part 2 is higher. The cooling effect of the cooling liquid 4 enables the injection melt 21 to reach the solidification state more quickly, significantly reduces the risk of plastic deformation or even permanent deformation of the injection molded part 2 due to incomplete solidification during the demolding process, and improves the stability of the demolding process and the final quality of the injection molded part 2. In addition, while achieving efficient cooling, the injection and extraction of the cooling liquid 4 can also achieve precise control of the pressure in the flexible bag 3. Compared with gas control, the increase and decrease of hydraulic pressure are more stable, further optimizing the demolding effect of the injection molded part 2 with complex structure.

[0035] According to one embodiment of the present application, the injection molded part 2 is an earphone shell, and the convex region 11 corresponds to the ear hook recessed area of the earphone shell.

[0036] Considering the demand for lightweight earphones and cost control in mass production, earphone shells are usually mass-produced by injection molding process. Due to the delicate structure and complex curved surface, especially the ear hook recessed area which often belongs to deep cavity and microstructure area, rigid molds are prone to sticking, deformation or incomplete demolding during demolding. Therefore, flexible demolding technology has been widely used in the production of earphone shells. However, although the existing flexible demolding method has solved the demolding difficulty problem to some extent, it still has the disadvantages of being unable to accurately control the degree of flexible deformation during demolding, low cooling efficiency, poor dimensional stability of the demolding part, and the like, which can easily lead to poor surface quality, size precision reduction, and deformation of the ear hook structure of the earphone shell product.

[0037] The improved demolding process is applied to the processing of the earphone shell in this embodiment, which can effectively realize stable demolding of the ear hook recessed area of the earphone shell. During demolding, the convex region 11 of the cavity 1 quickly retracts, avoiding the adhesion or friction of the ear hook area of the earphone with the mold cavity, significantly improving the smoothness and reliability of demolding.

[0038] In summary, the technical solution of the present application is particularly suitable for products such as earphone shells with delicate structure and high demolding difficulty, which can improve production efficiency, enhance product quality, reduce the rate of defective products, and has significant economic value and practical value.

[0039] Please refer to Figure 2 , as shown in Figure 2Fig. 1 is a flowchart of an injection molding process of a complex surface injection molded part according to an embodiment of the present application.

[0040] In a second aspect, the present application also provides an injection molding process of a complex surface injection molded part, which uses the demolding process of the above-mentioned embodiments to demold the injection molded part 2.

[0041] Since the injection molding process of the complex surface injection molded part disclosed in the present embodiment uses the demolding process of the complex surface injection molded part disclosed in the above-mentioned embodiments, it also has the technical effects of the above-mentioned demolding process, that is, by sequentially performing the retraction of the flexible convex region 11 and the expansion of the flexible concave region 12, the risk of deformation, damage or size precision not meeting the standard of the injection molded part 2 during demolding is effectively reduced, thereby significantly improving the yield rate and production efficiency of the complex surface injection molded part.

[0042] For example, taking the injection molding production of an earphone shell as an example: first, close the mold, inject molten plastic into the mold cavity 1 through the injection molding machine to form the initial structure of the earphone shell; stand still until the injection melt 21 is naturally cooled and solidified or accelerated cooling and solidification under the action of the external environment; when the earphone shell reaches a certain degree of solidification, open the mold, and the earphone shell is attached to one of the molds; make the flexible cavity 1 of the mold quickly retract the convex region 11 corresponding to the ear hook recessed area of the earphone, so that the convex region 11 of the cavity 1 is separated from the ear hook area of the earphone, avoiding being stuck during the subsequent deformation, and then making the convex region 11 of the cavity 1 protrude towards the side close to the earphone shell, thereby smoothly realizing the demolding of the earphone shell. After such a process, the problems such as strain, deformation or surface defects of the earphone shell in the ear hook area can be effectively avoided, and the appearance quality and size stability of the earphone shell are significantly improved.

[0043] Please refer to Figure 3 , as shown in Figure 3 Fig. 1 is a structure diagram of an injection molding mold of a complex surface injection molded part according to an embodiment of the present application.

[0044] In a third aspect, the present application also provides an injection molding mold of a complex surface injection molded part, which includes a concave mold 6 and a convex mold 5, which are buckled to form a cavity 1, the concave mold 6 includes a concave region 12 and a convex region 11, and the concave mold 6 is used to perform the demolding process of the above-mentioned embodiments.

[0045] Since the injection molding mold of the complex surface injection molded part disclosed in the present embodiment applies the demolding process of the complex surface injection molded part described in the above-mentioned embodiments, it also has the technical effects of the above-mentioned demolding process, that is, by quickly retracting the convex region 11 of the flexible cavity 1 and then protruding the concave region 12 towards the side close to the injection molded part 2, the problems such as sticking, strain or deformation of the recessed area of the injection molded part 2 during demolding are successfully avoided, thereby effectively ensuring the smoothness of the demolding process of the injection molded part 2 and improving the size precision, structural stability and surface quality of the injection molded part 2.

[0046] It should be understood that the division criteria of the cavity mold 6 and the punch 5 here is the adhesion condition of the injection molded part 2 after the mold is opened, the punch 5 is separated from the injection molded part 2, and the cavity mold 6 is adhered to the injection molded part 2. The punch 5 can also have a concave cavity, and the cavity mold 6 can also have a protruding cavity part. Here, only because the injection molded part 2 is usually adhered to the concave cavity 1 after the mold is opened in the mold opening process of the injection molding process, the side mold adhered to the injection molded part 2 is defined as the cavity mold 6.

[0047] According to one embodiment of the present application, the cavity mold 6 comprises a flexible bag 3, the flexible bag 3 is formed with a pressure regulating port for controlling the internal pressure of the flexible bag 3, and part of the outer wall of the flexible bag 3 constitutes the convex area 11 and at least part of the concave area 12.

[0048] The embodiment gives a specific adjustment method of the flexible cavity 1. By injecting or extracting fluid such as gas or liquid into or from the flexible bag 3 through the pressure regulating port, the internal pressure of the flexible bag 3 can be artificially controlled, thereby realizing the deformation of the outer wall of the flexible bag 3. The outer wall of the flexible bag 3 constitutes the convex area 11 and at least part of the concave area 12 of the cavity 1 of the cavity mold 6, so that the change of the internal pressure of the flexible bag 3 will directly cause the flexible deformation of the convex area 11 and the concave area 12 of the corresponding area of the mold cavity 1 to be accurately controllable, realizing the active deformation of the mold cavity 1 in the demolding process, ensuring the demolding stability and smoothness of the injection molded part 2 with complex structure, and effectively improving the dimensional accuracy, surface quality and production efficiency of the product.

[0049] Specifically, when the fluid is extracted through the pressure regulating port, the internal pressure of the flexible bag 3 decreases, the flexible bag 3 deforms by shrinking, and the convex area 11 constituted by the outer wall of the flexible bag 3 will quickly retract, so as to quickly separate from the deep cavity and concave structure area of the injection molded part 2, effectively avoiding the jamming or sticking phenomenon between the convex area 11 of the mold and the injection molded part 2 during demolding. On the contrary, when the fluid is injected into the flexible bag 3 through the pressure regulating port, the internal pressure of the bag increases, the flexible bag 3 deforms by swelling, and the concave area 12 constituted by the outer wall of the flexible bag 3 can expand or push out to the inside of the cavity 1, thereby further promoting the injection molded part 2 to smoothly separate from the mold, avoiding the deformation or strain of the injection molded part 2.

[0050] It should be noted that when the pressure inside the flexible bladder 3 decreases, both the concave area 12 and the convex area 11 have a tendency to shrink away from the injection molded part 2. When the concave area 12 shrinks, it is pulled by the convex area 11, and when the convex area 11 shrinks, the concave area 12 has less resistance to it. Therefore, even if the flexible bladder 3 is not divided, the convex area 11 will generally shrink first than the concave area 12. When the pressure inside the flexible bladder 3 increases, both the concave area 12 and the convex area 11 have a tendency to expand outward. At this time, even if the convex area 11 expands outward again and re-embeds into the recessed area of the injection molded part 2, it will not adversely affect the demolding process. More specifically, in the demolding process, the pressure inside the flexible bladder 3 increases and expands outward generally after the injection molded part 2 has initially separated from the mold surface. At this time, there is no strong adhesion and close contact between the injection molded part 2 and the cavity 1. Therefore, even if the convex area 11 re-embeds into the recessed area of the injection molded part 2, it only has a loose contact with the injection molded part 2, and there is no serious jamming or sticking phenomenon. The flexible structure of the convex area 11 can further play a positive role in ejecting the injection molded part 2.

[0051] In addition, even if the flexible bladder 3 only corresponds to the local concave area 12 of the mold cavity 1 instead of all the concave areas 12, the expansion deformation of the local concave area 12 is sufficient to effectively eject the injection molded part 2, thereby pushing the injection molded part 2 to smoothly separate from the mold surface and complete the demolding under the action of gravity. The concave area 12 without the flexible bladder 3 will not generally cause obvious jamming in the demolding process as long as it is reasonably designed and has a small contact area and demolding resistance with the injection molded part 2, and will not restrict the overall demolding effect.

[0052] Therefore, the flexible bladder 3 of the embodiment will not affect the smoothness and stability of the demolding process, and effectively ensures the dimensional accuracy and product quality of the injection molded part with complex surface.

[0053] Further, the flexible bladder 3 includes a first flexible bladder 31 and a second flexible bladder 32, and the pressure regulating port includes a first pressure regulating port and a second pressure regulating port respectively communicating with the first flexible bladder 31 and the second flexible bladder 32. Part of the outer wall of the first flexible bladder 31 corresponds to the convex area 11, and part of the outer wall of the second flexible bladder 32 corresponds to at least part of the concave area 12.

[0054] In the embodiment, the flexible bladder 3 is divided into a first flexible bladder 31 corresponding to the convex area 11 and a second flexible bladder 32 corresponding to the concave area 12, and independent first and second pressure regulating ports are respectively provided for pressure regulation. This can realize independent deformation control of the convex area 11 and the concave area 12, effectively avoid mutual interference between them, and make the shrinking of the convex area 11 and the ejection assistance of the concave area 12 more flexible and accurate, thereby improving the demolding effect of the injection molded part 2 with complex structure.

[0055] Furthermore, the flexible bag 3 further includes an envelope sleeve 7 , which covers the first flexible bag 31 and the second flexible bag 32 , and the outer surface of the envelope sleeve 7 forms a portion of the mold cavity 1 .

[0056] In this embodiment, an enveloping sleeve 7 is added to the exterior of the first and second flexible bladders 31, 32, and the outer surface of the enveloping sleeve 7 directly forms a portion of the mold cavity 1. Because the enveloping sleeve 7 is in direct contact with the surface of the molded product, when the pressure of the first and second flexible bladders 31, 32 is independently regulated to achieve the desired deformation and movement of the convex area 11 and concave area 12, the enveloping sleeve 7 can simultaneously provide a flexible transition and coordination function. Specifically, the enveloping structure of the enveloping sleeve 7 around the first and second flexible bladders 31, 32 effectively buffers the local deformation differences between the two flexible bladders 3 under different pressure conditions, significantly reducing or eliminating the obvious parting line, deformation steps, or localized sudden changes that may occur at the junction of the two flexible bladders 3, resulting in a more continuous and smooth transition effect on the surface of the cavity 1 in the connecting area. This structural design not only ensures the accuracy and stability of the overall structure of the mold cavity 1, but also further improves the smoothness of the demolding process, effectively guaranteeing the surface quality and dimensional accuracy of the molded product. It is particularly suitable for high-precision, complex structure injection molding applications.

[0057] According to one embodiment of the present invention, the injection mold for the complex surface injection molded part further includes a liquid pump, which is connected to the flexible bladder 3 and is used to input or extract cooling liquid 4 into the flexible bladder 3 to adjust the pressure in the flexible bladder 3 .

[0058] The injection mold of this embodiment also includes a liquid pump, which precisely regulates the pressure within the flexible bladder 3, thereby rapidly controlling its deformation state and ensuring the dimensional accuracy of the mold cavity 1 and the high quality of the molded product. Furthermore, as discussed in the above embodiments, regulating the internal pressure of the flexible bladder 3 with coolant 4 effectively accelerates the solidification of the surface of the molded part 2, preventing deformation of the part 2 during demolding.

[0059] In the description of this application, it should be noted that, unless otherwise specified, "multiple" means more than two; the terms "upper", "lower", "left", "right", "inside", "outside", etc., indicating directions or positional relationships, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly perpendicular, but is within the allowable error range. "Parallel" is not strictly parallel, but is within the allowable error range.

[0060] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0061] The directional words appearing in the above description are all directions shown in the figures, and do not limit the specific structure of this application. In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0062] The above description is only a preferred embodiment of the present application and does not limit the patent scope of the present application. All equivalent structural transformations made based on the design concept of the present application and the contents of the present application description and drawings, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A demoulding process for complex surface injection molded parts, characterized in that: The demoulding process is applicable to the separation of an injection mold having a flexible cavity from an injection molded part, wherein the flexible cavity includes at least one convex area and a concave area corresponding to the convex area, wherein the convex area is used to form a concave outer contour of the injection molded part, and the concave area is used to form the remaining outer contour of the injection molded part. The demoulding process comprises the following steps: B1, moving the convex area away from the injection molded part and creating a gap with the injection molded part; B2. The concave area is made to bulge toward the side close to the injection molded part, and the injection molded part is ejected to separate the injection molded part from the injection mold.

2. The demoulding process of complex surface injection molded parts according to claim 1, characterized in that: The injection mold includes a flexible bladder, a bladder wall of which forms at least a portion of the mold cavity; The step B1 includes: reducing the internal pressure of the flexible bag so that the convex area moves away from the injection molded part and creates a gap with the injection molded part; The step B2 includes: increasing the internal pressure of the flexible bag to cause the concave area to bulge toward the side close to the injection molded part, and ejecting the injection molded part to separate the injection molded part from the injection mold.

3. The demoulding process of complex surface injection molded parts according to claim 2, characterized in that: The flexible bag is filled with cooling liquid, and the pressure inside the flexible bag can be increased or decreased by injecting or withdrawing the cooling liquid.

4. The demoulding process of a complex surface injection molded part according to any one of claims 1 to 3, characterized in that: The injection molded part is an earphone shell, and the convex area corresponds to the ear-hanging concave area of ​​the earphone shell.

5. An injection molding process for complex surface injection molded parts, characterized in that: The injection molded part is demoulded using the demoulding process described in any one of claims 1 to 4.

6. An injection mold for complex surface injection molded parts, characterized in that: The die comprises a concave die and a convex die, which are engaged to form a cavity. The die comprises a concave area and a convex area. The die is used to perform the demoulding process according to any one of claims 1 to 4.

7. The injection mold for complex surface injection molded parts according to claim 6, characterized in that: The die includes a flexible bladder having a pressure regulating port formed therein for controlling the internal pressure of the flexible bladder. Part of the outer wall of the flexible bladder constitutes the convex area and at least part of the concave area.

8. The injection mold for complex surface injection molded parts according to claim 7, characterized in that: The flexible bag includes a first flexible bag and a second flexible bag, and the pressure regulating port includes a first pressure regulating port and a second pressure regulating port respectively connected to the first flexible bag and the second flexible bag. Part of the outer wall of the first flexible bag corresponds to the convex area, and part of the outer wall of the second flexible bag corresponds to at least part of the concave area.

9. The injection mold for complex surface injection molded parts according to claim 8, characterized in that: The flexible bag further includes an envelope sleeve, which covers the first flexible bag and the second flexible bag, and an outer surface of the envelope sleeve forms a portion of the cavity.

10. The injection mold for a complex surface injection molded part according to any one of claims 7 to 9, characterized in that: The injection mold for the complex surface injection molded part further includes a liquid pump, which is communicated with the flexible bag and is used to input or extract cooling liquid into or from the flexible bag to adjust the pressure in the flexible bag.

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