Self-adaptive bionic adsorption vacuum negative pressure forming structure

Abstract

The invention discloses a self-adaptive bionic adsorption vacuum negative pressure forming structure which comprises a mold body, a plurality of bionic adsorption units are arranged on the working molded surface of the mold body, and each bionic adsorption unit comprises a center solid boss and an annular vacuum groove formed around the center solid boss. The annular vacuum groove is connected with a main vacuum cavity formed in the mold body through a radial communicating groove, the top of the center solid boss is of a curved surface structure matched with the molded surface of a product, no through hole exists in the surface of the center solid boss, and an elastic sealing cover film covers a groove opening of the annular vacuum groove. And the elastic sealing cover film is fixed on the surface of the mold body through the annular pressing edge and is bridged above the annular vacuum groove. According to the self-adaptive bionic adsorption vacuum negative-pressure forming structure, natural delay and guidance of the adsorption sequence are achieved, local tension cracks and incompact attachment of materials are effectively avoided, and the forming uniformity and the product yield are improved.

Description

Technical Field

[0001] This invention relates to the field of mold forming technology, specifically to an adaptive biomimetic adsorption vacuum negative pressure forming structure. Background Technology

[0002] Vacuum forming is a common plastic molding process. It involves covering a heated and softened plastic sheet onto the surface of a mold, then using vacuum suction to force the sheet to adhere tightly to the mold cavity. After cooling, the desired shape is obtained. This process is widely used in industries such as home appliances, automobiles, and packaging, and its molding quality is closely related to the vacuum adsorption design of the mold surface.

[0003] Currently, most vacuum forming molds use a method of uniformly distributing small holes across the entire mold surface for adsorption. These holes directly connect to the vacuum cavity inside the mold. This design has significant drawbacks when dealing with products with large curvature variations: In the raised areas of the mold, the plastic sheet first contacts the mold surface, but because these areas already have through holes, the vacuum immediately activates, causing the material to be adsorbed and fixed prematurely at the top. Meanwhile, the surrounding areas have not yet adhered, and the material continues to stretch outwards, easily causing excessive thinning or even cracking in the central area of ​​the raised surface. Simultaneously, in the recessed or deep cavities of the mold, because the sheet arrives later, the vacuum is consumed prematurely, resulting in insufficient adsorption force and loose sheet adhesion, leading to bubbling, wrinkles, or unclear outlines. These problems directly affect the surface quality, thickness uniformity, and overall forming accuracy of the product, making it difficult to meet the production requirements of high-demand products. Summary of the Invention

[0004] The purpose of this invention is to provide an adaptive biomimetic adsorption vacuum negative pressure forming structure to solve the problems mentioned in the background art. In the current vacuum negative pressure forming mold, the uniform distribution of adsorption holes causes the sheet to be adsorbed too early in the raised areas, resulting in excessive stretching and cracking of the material. In the recessed areas, the vacuum is consumed too early, resulting in poor adhesion, which in turn affects the surface quality, thickness uniformity and forming accuracy of the product.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an adaptive biomimetic adsorption vacuum negative pressure forming structure, comprising a mold body, wherein a plurality of biomimetic adsorption units are provided on the working surface of the mold body, each biomimetic adsorption unit comprising a central solid boss and an annular vacuum groove surrounding the central solid boss, the annular vacuum groove being connected to a main vacuum cavity located inside the mold body via a radially communicating groove, the top of the central solid boss being a curved surface structure matching the product profile and having no through holes on the surface, and an elastic sealing cover film covering the opening of the annular vacuum groove, the elastic sealing cover film being fixed to the surface of the mold body by an annular pressing edge and spanning above the annular vacuum groove.

[0006] Preferably, the central solid boss is a frustum structure that protrudes integrally from the surface of the mold body, and its height is 0.8-1.2mm.

[0007] Preferably, the annular vacuum groove is a closed annular groove surrounding the central solid boss, with a trapezoidal cross-section, a width of 1.5-2.5 mm, and a depth of 1.0-1.8 mm.

[0008] Preferably, the radial connecting groove is a plurality of slit-like channels opened along the radial direction inside the mold body, the number of which is 3-6, evenly distributed on the outside of the annular vacuum groove, and one end of the radial connecting groove is connected to the annular vacuum groove, and the other end is connected to the main vacuum cavity.

[0009] Preferably, the elastic sealing cover is a polyurethane film with a thickness of 0.05-0.15 mm, and is fitted to the annular vacuum groove to form a seal.

[0010] Preferably, the annular pressing edge is a metal ring embedded in the surface of the mold body, and the inner edge of the annular pressing edge presses against the outer periphery of the elastic sealing cover film, while the outer edge of the annular pressing edge is flush with the surface of the mold body.

[0011] Preferably, the main vacuum chamber is a cavity distributed along the surface inside the mold body, and the main vacuum chamber is connected to an external vacuum pump through an air extraction pipeline.

[0012] Preferably, the central solid boss, the annular vacuum groove, and the radial connecting groove are integrally machined structures.

[0013] Preferably, the inner wall of the annular vacuum trough is an inwardly inclined guide slope with an inclination angle of 15°-30°.

[0014] Preferably, the central region of the elastic sealing cover film is provided with a pre-protrusion that matches the shape of the top of the central solid boss, and a gap of 0.1-0.3mm is left between the pre-protrusion and the top of the central solid boss.

[0015] Compared with existing technologies, the beneficial effects of this invention are: the adaptive biomimetic adsorption vacuum negative pressure forming structure achieves natural delay and guidance of the adsorption sequence, effectively avoiding localized material tearing and poor bonding, and improving forming uniformity and product yield. This structure, through the "island-like" layout design of the central solid boss and the annular vacuum groove, prevents adsorption in the initial contact area of ​​the sheet. The cooperation between the elastic sealing cap and the annular pressing edge enables passive opening and closing of the vacuum channel. The radial connecting groove stably delivers the negative pressure of the main vacuum chamber to the annular vacuum groove, ensuring reliable adsorption response to the sheet bonding sequence. The overall structure is simple, the response is precise, and it significantly improves the forming quality of complex curved surface products. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the adaptive biomimetic adsorption vacuum negative pressure forming structure of the present invention;

[0017] Figure 2 This invention relates to an adaptive biomimetic adsorption vacuum negative pressure forming structure. Figure 1 Enlarged structural diagram at point A in the middle;

[0018] Figure 3 This is a schematic diagram of the forming surface structure of the mold body of the adaptive biomimetic adsorption vacuum negative pressure forming structure of the present invention;

[0019] Figure 4 This is a schematic diagram of the biomimetic adsorption unit structure of an adaptive biomimetic adsorption vacuum negative pressure forming structure according to the present invention;

[0020] Figure 5 This is a schematic diagram of the connection structure between the annular vacuum groove and the main vacuum cavity of the adaptive biomimetic adsorption vacuum negative pressure forming structure of the present invention.

[0021] In the diagram: 1. Mold body; 2. Central solid boss; 3. Annular vacuum groove; 4. Radial connecting groove; 5. Main vacuum cavity; 6. Elastic sealing cover; 7. Annular pressing edge. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Please see Figure 1-5This invention provides a technical solution: an adaptive biomimetic adsorption vacuum negative pressure forming structure, comprising a mold body 1. Multiple biomimetic adsorption units are provided on the working surface of the mold body 1. Each biomimetic adsorption unit includes a central solid boss 2 and an annular vacuum groove 3 surrounding the central solid boss 2. The annular vacuum groove 3 is connected to a main vacuum cavity 5 located inside the mold body 1 via a radially communicating groove 4. The top of the central solid boss 2 is a curved surface structure matching the product profile and has no through holes. An elastic sealing cover 6 covers the opening of the annular vacuum groove 3. The elastic sealing cover 6 is fixed to the surface of the mold body 1 by an annular pressing edge 7 and spans across the annular vacuum groove. Above 3, when the heated and softened plastic sheet is pressed against the mold body 1 under external atmospheric pressure, it first contacts the top curved surface of the central solid boss 2 in each biomimetic adsorption unit that does not have through holes. Since this area has no vacuum channel and the surface is smooth, the sheet can slide freely without being adsorbed and fixed, avoiding premature locking of the material at the protrusion. As the sheet continues to deform and press down, its edge gradually approaches the area of ​​the annular vacuum groove 3, pressing the elastic sealing cover 6 to create a gap between it and the groove opening of the annular vacuum groove 3. Vacuum is introduced into the annular vacuum groove 3 through the main vacuum chamber 5 and the radial connecting groove 4, thereby forming an effective vacuum in the area corresponding to the sheet and the annular vacuum groove 3. The adsorption process employs an adaptive response mechanism where "adsorption does not occur in the central area that comes into contact first, but only in the peripheral areas that come into contact later." The elastic sealing cover 6 opens under sheet pressure and recovers its seal through its own elasticity after the pressure is released. Combined with the fixing effect of the annular pressure edge 7, this ensures stable operation of the cover 6. This allows the vacuum adsorption force to act only locally when the sheets are sufficiently close, effectively guiding the material to stretch and flow uniformly. This solves the problems in existing technologies, such as premature fixation of material in raised areas due to through-holes covering the entire surface, leading to tensile cracking, and poor adhesion, bubbling, and blurred contours in deep cavities caused by premature vacuum depletion. This significantly improves the molding quality of complex curved surface products. Regarding yield, the central solid boss 2 is a frustum structure that protrudes integrally from the surface of the mold body 1, with a height of 0.8-1.2mm. The frustum shape and precise height control of the central solid boss 2 ensure that it preferentially contacts the sheet material in the early stage of molding and provides smooth support, avoiding stress concentration. At the same time, the design without through holes on its surface achieves non-adsorption transition in this area, creating conditions for the delayed adsorption of the subsequent annular vacuum groove 3, effectively preventing the material from being prematurely fixed at the high point and overstretched. The annular vacuum groove 3 is a closed annular groove set around the central solid boss 2, with a trapezoidal cross-section, a width of 1.5-2.5mm, and a depth of 1.0-1.The sheet is 8mm thick. When the sheet is pressed down, its edge presses against the elastic sealing film 6 to open the vacuum channel, forming an annular adsorption force. The trapezoidal cross-section facilitates the sliding of the sheet and enhances the adsorption stability, achieving orderly bonding from the center to the periphery, preventing material accumulation or tearing. The radial connecting groove 4 consists of multiple slit-like channels opened along the radial direction inside the mold body 1, numbering 3-6, evenly distributed on the outside of the annular vacuum groove 3. One end of the radial connecting groove 4 connects to the annular vacuum groove 3, and the other end connects to the main vacuum chamber 5. This structure allows the negative pressure in the main vacuum chamber 5 to be stably introduced into the annular vacuum groove 3 through multiple radially evenly distributed channels, ensuring that the adsorption force is released evenly in the circumferential direction, avoiding insufficient or delayed local suction, and ensuring that the sheet is synchronously and evenly bonded in the area surrounding the central boss. The elastic sealing film 6 has a thickness of 0.05-0.A 15mm polyurethane film, under normal conditions, adheres to the opening of the annular vacuum groove 3 under its own tension to form a seal. This elastic sealing cover 6 maintains the seal of the annular vacuum groove 3 when the sheet is not fully adhered, preventing premature vacuum leakage. When the edge of the sheet is pressed down, slight pressure can deform and open the elastic sealing cover 6, achieving immediate vacuum conduction. This ensures that the adsorption action only occurs when needed, effectively cooperating with the non-adsorption area of ​​the central solid boss 2 to achieve adaptive control of the bonding sequence. The annular pressing edge 7 is a metal ring embedded in the surface of the mold body 1, with the inner edge of the annular pressing edge 7 pressing against the outer periphery of the elastic sealing cover 6, and the outer edge of the annular pressing edge 7 flush with the surface of the mold body 1. This structure... The rigid fixation of the metal ring ensures that the elastic sealing membrane 6 remains stable during repeated use, preventing displacement or warping. It also maintains uniform pressure, ensuring reliable sealing and opening actions. This prevents air leakage or adsorption failure due to loosening of the elastic sealing membrane 6, guaranteeing the long-term stability and consistency of the biomimetic adsorption unit. The main vacuum chamber 5 is a cavity distributed along the mold surface inside the mold body 1, and it is connected to an external vacuum pump via a suction pipe. This structure provides a stable and sufficient negative pressure source for the entire adsorption system. The vacuum pressure is evenly delivered through the cavities distributed along the mold surface, ensuring that the annular vacuum grooves 3 of each biomimetic adsorption unit simultaneously obtain sufficient suction upon triggering, preventing pressure decay. Uneven or uneven bonding can lead to poor local adhesion. To ensure the reliability and consistency of the molding process, the central solid boss 2, the annular vacuum groove 3, and the radial connecting groove 4 are integrally machined. This structure ensures precise and leak-free connection between the central solid boss 2, the annular vacuum groove 3, and the radial connecting groove 4, improving vacuum transfer efficiency. It also enhances the overall structural strength and sealing reliability, preventing assembly errors or loose interfaces from affecting the adsorption effect and ensuring stable operation of the bionic unit. The inner wall of the annular vacuum groove 3 is an inwardly inclined guide slope with an inclination angle of 15°-30°. During the sheet pressing process, this inclined inner wall of the annular vacuum groove 3 guides the material to smoothly transition into the annular vacuum. The grooved area reduces localized stress concentration and facilitates uniform deformation and opening of the elastic sealing cover 6, improving the stability and adhesion quality of adsorption initiation. The central area of ​​the elastic sealing cover 6 has a pre-protrusion that matches the shape of the top of the central solid boss 2. A gap of 0.1-0.3mm is left between this pre-protrusion and the top of the central solid boss 2. This structure ensures that the sheet material initially acts only on the central solid boss 2 without triggering adsorption. This gap structure forms a buffer zone, ensuring that the material can freely extend in the central area. Only after the deformation deepens does it compress the elastic sealing cover 6 to open the channel of the annular vacuum groove 3, achieving precise delay in the adsorption action and effectively preventing premature stretching and cracking of the material at high points.

[0024] Working principle: When using this adaptive biomimetic adsorption vacuum negative pressure forming structure, the plastic sheet is first heated to a softened state, and then it is placed on the surface of the mold body 1. The external vacuum pump is started to evacuate the main vacuum chamber 5 through the suction pipe. At this time, because the elastic sealing cover film 6 adheres to the groove of the annular vacuum groove 3 under its own tension and is fixed and sealed by the annular pressing edge 7, the vacuum will not leak prematurely. When the sheet begins to adhere to the surface of the mold body 1 under atmospheric pressure, the first contact is with the top curved surface of the central solid boss 2 in each biomimetic adsorption unit, because there are no through holes in this area. Furthermore, the surface is smooth, and the sheet does not adhere to this area. As the sheet continues to be pressed down and deformed, its edge gradually presses against the elastic sealing cover 6, creating a gap between it and the annular vacuum groove 3. Vacuum is introduced into the annular vacuum groove 3 through the radial connecting groove 4 from the main vacuum chamber 5, causing the sheet to be adsorbed and adhered tightly in the annular area. At the same time, the gap between the pre-protrusion in the center of the elastic sealing cover 6 and the top of the central solid boss 2 ensures that the central area remains in a non-adsorption state until the periphery is fully adhered and the overall pressure increases. The cover further deforms to complete the final sealing and adsorption, thus completing a series of tasks.

[0025] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An adaptive biomimetic adsorption vacuum negative pressure forming structure, comprising a mold body (1), characterized in that: The working surface of the mold body (1) is provided with multiple biomimetic adsorption units. Each biomimetic adsorption unit includes a central solid boss (2) and an annular vacuum groove (3) surrounding the central solid boss (2). The annular vacuum groove (3) is connected to the main vacuum cavity (5) located inside the mold body (1) through a radial connecting groove (4). The top of the central solid boss (2) is a curved surface structure that matches the product surface and has no through holes. The groove opening of the annular vacuum groove (3) is covered with an elastic sealing cover film (6). The elastic sealing cover film (6) is fixed to the surface of the mold body (1) by an annular pressing edge (7) and spans across the annular vacuum groove (3).

2. The adaptive biomimetic adsorption vacuum negative pressure forming structure according to claim 1, characterized in that: The central solid boss (2) is a frustum structure that is raised from the surface of the mold body (1) as a whole, and its height is 0.8-1.2mm.

3. The adaptive biomimetic adsorption vacuum negative pressure forming structure according to claim 1, characterized in that: The annular vacuum groove (3) is a closed annular groove surrounding the central solid boss (2). Its cross-section is trapezoidal, with a width of 1.5-2.5 mm and a depth of 1.0-1.8 mm.

4. The adaptive biomimetic adsorption vacuum negative pressure forming structure according to claim 1, characterized in that: The radial connecting groove (4) is a plurality of slit-shaped channels opened in the radial direction inside the mold body (1), with a quantity of 3-6, evenly distributed on the outside of the annular vacuum groove (3), and one end of the radial connecting groove (4) is connected to the annular vacuum groove (3), and the other end is connected to the main vacuum cavity (5).

5. The adaptive biomimetic adsorption vacuum negative pressure forming structure according to claim 1, characterized in that: The elastic sealing cover (6) is a polyurethane film with a thickness of 0.05-0.15mm, and is attached to the groove of the annular vacuum groove (3) to form a seal.

6. The adaptive biomimetic adsorption vacuum negative pressure forming structure according to claim 1, characterized in that: The annular pressing edge (7) is a metal ring embedded in the surface of the mold body (1), and the inner edge of the annular pressing edge (7) presses against the outer periphery of the elastic sealing cover film (6), and the outer edge of the annular pressing edge (7) is flush with the surface of the mold body (1).

7. The adaptive biomimetic adsorption vacuum negative pressure forming structure according to claim 1, characterized in that: The main vacuum chamber (5) is a cavity distributed along the surface inside the mold body (1), and the main vacuum chamber (5) is connected to an external vacuum pump through an air extraction pipeline.

8. The adaptive biomimetic adsorption vacuum negative pressure forming structure according to claim 1, characterized in that: The central solid boss (2), the annular vacuum groove (3) and the radial connecting groove (4) are integrally formed structures.

9. The adaptive biomimetic adsorption vacuum negative pressure forming structure according to claim 1, characterized in that: The inner wall of the annular vacuum groove (3) is an inwardly inclined guide slope with an inclination angle of 15°-30°.

10. The adaptive biomimetic adsorption vacuum negative pressure forming structure according to claim 1, characterized in that: The central region of the elastic sealing cover (6) is provided with a pre-protrusion that matches the shape of the top of the central solid boss (2), and there is a gap of 0.1-0.3mm between the pre-protrusion and the top of the central solid boss (2).

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