Accurate injection mold for manufacturing large-inclination-angle injection product and injection molding method thereof

Abstract

The invention discloses a precise injection mold for manufacturing a large-inclination-angle injection product and an injection molding method thereof, and relates to the technical field of injection molds, the precise injection mold comprises an upper mold and a lower mold which are arranged in a mutually aligned mode, the bottom of the lower mold is slidably connected with an ejector plate through a guide shaft, and a first spring is arranged between the lower mold and the ejector plate; a dislocation mechanism is arranged on the lower die; the dislocation mechanism comprises a telescopic air bag and a driving mechanism. The dislocation mechanism is arranged, and the driving mechanism drives the telescopic air bag to expand, so that the telescopic air bag is tightly attached to the inner wall of a large-angle inner buckle of an injection product and serves as a part of a cavity for forming the inner buckle, and the size precision of the inner buckle of the product is ensured; the driving mechanism drives the telescopic air bag to contract, so that the telescopic air bag is separated from the inner buckle surface of the product, rigid friction with the product is avoided, smooth demolding of the product is achieved by matching with ejection action of the ejector plate, rigid inclined ejection is replaced by flexible contact, mechanical abrasion is reduced fundamentally, and the service life of the mold is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of injection molds, and in particular to a precision injection mold for producing injection molded products with large bevel angles and an injection molding method thereof. Background Art

[0002] Due to product structure limitations, some injection molds, such as those for the lower B-pillar of automobiles, require a steeply inclined ejector head. This structure operates as follows: guided and driven by an ejector rod, the ejector head moves in the direction of the product's opening, adapting to the specific demolding requirements of the product's structure. However, existing precision injection molds for high-angle injection molding still suffer from the following drawbacks:

[0003] For example, Chinese patent publication number CN114434757A discloses a mold for large-angle undercut demolding, which belongs to the field of injection mold technology. It includes a fixed mold plate, a movable mold plate and an ejector plate. The ejector plate is arranged below the movable mold plate. It also includes an ejector rod, a slider and a slider seat. The slider seat is fixed to the movable mold plate. The slider is located above the slider seat and slides with it left and right. An inclined ejector block is provided on the left side of the slider. Both the slider seat and the slider are provided with a guide hole for the ejector rod to pass through. The bottom end of the ejector rod is vertically fixed to the ejector plate, and its top end is provided with an inclined section inclined to the "left". The inclined section is located in the guide hole in the slider. The right side of the inclined section is in contact with the guide hole, and the left side is at a certain distance from the wall of the guide hole. The present invention has a simple and reasonable structure and is easy to demold. It can form the undercut part of the mold in one step, reducing costs and improving production efficiency. It can be promoted and used in more mold applications.

[0004] The aforementioned steeply angled downward slope of the ejector block during mold opening inevitably creates continuous and intense mechanical friction between the ejector block and the molded surface and the mold's guiding mating surfaces. This friction not only causes visible wear on the ejector block's working surface, product contact areas, and mold mating surfaces, but also increases clearances and shifts in the mold path due to component wear. Ultimately, this reduces the accuracy of the ejector release, impacting both product quality and mold life. Summary of the Invention

[0005] The purpose of this application is to provide a precise injection mold and an injection molding method for producing large-angle injection-molded products, which can effectively solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above-mentioned objectives, the present application provides the following technical solutions: a precision injection mold for producing injection-molded products with large bevel angles, comprising an upper mold and a lower mold arranged in opposition to each other, the bottom of the lower mold being slidably connected to a pin plate via a guide shaft, and a first spring being arranged between the lower mold and the pin plate; a dislocation mechanism being provided on the lower mold; the dislocation mechanism comprising: a telescopic airbag and a driving mechanism; wherein a receiving groove is provided on the lower mold, and the telescopic airbag is arranged in the receiving groove; when the telescopic airbag is in an expanded state, the telescopic airbag is adapted to the inverted position of the injection-molded product; when the telescopic airbag is in a compressed state, the telescopic airbag is allowed to detach from the inverted position of the injection-molded product; the driving mechanism is provided on the lower mold and is used to control the expansion or compression of the telescopic airbag.

[0007] Preferably, the driving mechanism includes a push rod, a cylinder, a piston and a linkage mechanism; the push rod passes through the lower mold and is connected to the ejector plate; the cylinder is fixed to the lower mold, the piston is slidably connected to the cylinder, and the push rod is connected to the piston; the linkage mechanism is installed between the ejector plate and the push rod; when the ejector plate moves, the linkage mechanism is allowed to drive the push rod to move, thereby driving the piston to slide in the cylinder.

[0008] Preferably: the linkage mechanism includes a rack, a mounting block and a gear; the rack is fixed to the ejector plate, the mounting block is fixed to the lower mold, the gear is connected to the mounting block by rotating around its axis, and a tooth groove is provided on one side of the ejector rod; one side of the gear is engaged with the rack, and the other side of the gear is engaged with the ejector rod through the tooth groove.

[0009] Preferably: a plurality of mutually hinged rotating plates are provided on the outside of the telescopic airbag; the rotating plates are in contact with the outer wall of the telescopic airbag; one of the rotating plates is fixed to the lower mold, and a connecting plate is hinged on the other rotating plate away from the rotating plate; when the telescopic airbag is expanded, the plurality of rotating plates form a bending structure that is compatible with the undercut inner wall of the injection molded product; the connecting plate is connected to the ejector rod; when the ejector rod moves, it is allowed to drive the connecting plate to move, thereby driving the plurality of rotating plates to fold or unfold.

[0010] Preferably, a top plate is fixed on the top rod, and a second spring is provided between the connecting plate and the top plate.

[0011] Preferably, the dislocation mechanism further includes an active control mechanism for actively controlling the air pressure in the telescopic airbag; the active control mechanism includes a micro air pump mounted on the cylinder body, and the output end of the micro air pump is connected to the interior of the telescopic airbag through a connecting pipe.

[0012] Preferably, a pressure sensor is provided in the telescopic airbag and is used to detect the air pressure in the telescopic airbag.

[0013] Preferably, the telescopic airbag comprises an outer temperature-resistant layer, a middle reinforced fiber mesh layer, and an inner sealing layer; and the telescopic airbag is made of a fluororubber composite material.

[0014] A precision injection molding method for producing a large-angle injection molded product, comprising the above-mentioned precision injection mold for producing a large-angle injection molded product, specifically comprising the following steps:

[0015] Step 1: Airbag drive: When closing the mold, the driving mechanism drives the telescopic airbag in the forward direction to expand, so that the expansion direction of the telescopic airbag matches the large-angle inward buckle demoulding trajectory, so that the expanded telescopic airbag fits the large-angle inward buckle inner wall of the injection-molded product; when opening the mold, the driving mechanism drives the telescopic airbag in the reverse direction to contract, so that the telescopic airbag contracts and breaks away from the inward buckle of the injection-molded product, allowing the injection-molded product to be removed from the mold;

[0016] Step 2: Dynamic adjustment: During the mold closing and injection molding process, the driving force is adjusted in real time through the active control mechanism according to the shrinkage difference of the material, thereby adjusting the expansion degree of the telescopic airbag.

[0017] Preferably: in step 2, the pressure control method of the telescopic airbag is: according to the ambient temperature T and the initial pressure P initial Determine the standard control pressure after temperature correction; specifically, step 1: input parameter definition:

[0018] Input 1: ambient temperature T; unit: K;

[0019] Input 2: Initial pressure P initial ;Unit: kPa;

[0020] Step 2: Determine standard reference conditions:

[0021] Standard temperature: T ref =293.15K

[0022] Standard initial pressure: P ref

[0023] Step 3: Calculate the temperature compensation coefficient:

[0024] According to the ideal gas state equation, pressure is proportional to temperature:

[0025]

[0026] where K T is the temperature compensation coefficient;

[0027] Step 4: Calculate the temperature-corrected pressure:

[0028] Correct the initial pressure to the equivalent pressure at standard temperature:

[0029]

[0030] Step 5: Overlay the standard control pressure offset:

[0031] According to the airbag design specifications, the standard control pressure P standard is the sum of the temperature-corrected pressure and a fixed offset ΔP:

[0032] P standard =P temp_corrected +ΔP

[0033] Where ΔP is the design constant;

[0034] Step 6: Output standard control pressure:

[0035] The final output standard control pressure is:

[0036]

[0037] Unit: kPa.

[0038] In summary, the technical effects and advantages of the present invention are as follows:

[0039] 1. The present invention has a reasonable structure. By providing a dislocation mechanism, the drive mechanism drives the expansion of the telescopic airbag, so that it fits tightly with the large-angle inward-buckling inner wall of the injection-molded product, serving as part of the inward-buckling cavity, ensuring the inward-buckling dimensional accuracy of the product. The drive mechanism drives the telescopic airbag to contract, so that it separates from the inward-buckling surface of the product, avoiding rigid friction with the product. The ejection action of the ejector plate realizes smooth demolding of the product. Flexible contact replaces rigid inclined ejection, fundamentally reducing mechanical wear and extending the life of the mold.

[0040] 2. The present invention sets an active control mechanism to compensate for the insufficient air pressure generated by the piston drive and the slow contraction of the airbag during mold opening and demolding. At the same time, it can compensate for the limitations of the passive piston drive, improve the air pressure control accuracy in the telescopic airbag, and solve the problem of insufficient filling or overpressure of the product inner buckle caused by unstable air pressure in traditional passive drive. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0042] Figure 1 It is a schematic diagram of the overall three-dimensional structure of the present invention;

[0043] Figure 2It is a schematic diagram of a three-dimensional enlarged structure of part of the structure of the present invention;

[0044] Figure 3 For the present invention Figure 2 Schematic diagram of the enlarged structure of area A in the middle;

[0045] Figure 4 It is a partially cutaway three-dimensional enlarged structural schematic diagram of the present invention;

[0046] Figure 5 For the present invention Figure 4 Schematic diagram of the enlarged structure of the middle B area;

[0047] Figure 6 This is a partially cutaway, three-dimensional, enlarged structural diagram of the lower mold structure of the present invention;

[0048] Figure 7 It is a three-dimensional enlarged structural diagram of part of the structure of the dislocation mechanism of the present invention;

[0049] Figure 8 For the present invention Figure 7 Schematic diagram of the enlarged structure of the middle C region;

[0050] Figure 9 It is a partially cutaway, three-dimensional, and enlarged structural diagram of a portion of the structure of the dislocation mechanism of the present invention;

[0051] Figure 10 Flow chart of the method of the present invention.

[0052] In the figure: 1. upper mold; 2. lower mold; 3. ejector plate; 4. first spring; 5. offset mechanism; 51. telescopic airbag; 52. driving mechanism; 521. ejector rod; 522. cylinder; 523. piston; 524. linkage mechanism; 5241. rack; 5242. mounting block; 5243. gear; 5244. tooth groove; 53. rotating plate; 54. connecting plate; 55. ejector plate; 56. second spring; 57. active control mechanism; 571. micro air pump; 572. connecting pipe. DETAILED DESCRIPTION

[0053] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0054] Example 1: Please refer to Figures 1-9The shown embodiment shows a precision injection mold for producing injection-molded products with large bevel angles, comprising an upper mold 1 and a lower mold 2 which are positioned opposite each other, wherein the bottom of the lower mold 2 is slidably connected to a pin plate 3 via a guide shaft, and a first spring 4 is arranged between the lower mold 2 and the pin plate 3; a dislocation mechanism 5 is provided on the lower mold 2; the dislocation mechanism 5 comprises: a telescopic airbag 51 and a driving mechanism 52; wherein, a receiving groove is provided on the lower mold 2, and the telescopic airbag 51 is arranged in the receiving groove; when the telescopic airbag 51 is in an expanded state, the telescopic airbag 51 is adapted to the inverted position of the injection-molded product; when the telescopic airbag 51 is in a compressed state, the telescopic airbag 51 is allowed to detach from the inverted position of the injection-molded product; the driving mechanism 52 is arranged on the lower mold 2 and is used to control the expansion or compression of the telescopic airbag 51.

[0055] It should be noted that, in the mold closing state, the driving mechanism 52 drives the telescopic airbag 51 to expand, so that it fits tightly with the inner wall of the steep undercut structure of the injection molded product with a large inward bend, such as under the B-pillar of an automobile, and serves as part of the cavity for the inward bend molding, thereby ensuring the dimensional accuracy of the product.

[0056] When the mold is opened, the ejector plate 3 slides upward under the action of the first spring 4; at the same time, the driving mechanism 52 moves in the opposite direction, controlling the compression and contraction of the telescopic airbag 51 to separate from the inner buckle surface of the product, avoiding rigid friction with the product, and cooperating with the ejection action of the ejector plate 3 to achieve smooth demoulding of the product;

[0057] By replacing the rigid inclined ejector with the flexible contact of the telescopic airbag 51, mechanical wear is fundamentally reduced and the life of the mold is extended; the expansion / compression direction of the telescopic airbag 51 can accurately match the large-angle inward-buckling demoulding trajectory, solving the demoulding interference problem caused by the fixed trajectory of the traditional inclined ejector and improving the product molding quality.

[0058] See also Figure 4-Figure 5 and Figure 9 The driving mechanism 52 includes a push rod 521, a cylinder body 522, a piston 523 and a linkage mechanism 524; the push rod 521 passes through the lower mold 2 and is connected to the ejector plate 3; the cylinder body 522 is fixed to the lower mold 2, the piston 523 is slidably connected in the cylinder body 522, and the push rod 521 is connected to the piston 523; the linkage mechanism 524 is installed between the ejector plate 3 and the push rod 521; when the ejector plate 3 moves, the linkage mechanism 524 is allowed to drive the push rod 521 to move, thereby driving the piston 523 to slide in the cylinder body 522.

[0059] It should be noted that the linear motion of the ejector plate 3 is converted into the linear motion of the ejector rod 521 through the linkage mechanism 524, and the ejector rod 521 pushes the piston 523 to slide back and forth in the cylinder 522; the interior of the cylinder 522 is a closed chamber, which is connected to the telescopic airbag 51 through an air passage. When the piston 523 slides, the volume of the gas in the cylinder 522 changes: when the piston 523 compresses the gas in the cylinder 522, the gas enters the telescopic airbag 51 through the air passage, causing it to expand; when the piston 523 retreats, negative pressure is formed in the cylinder 522, and the gas in the telescopic airbag 51 flows back, causing it to be compressed.

[0060] The compressibility of the gas buffers the driving force, avoiding rigid impact during the ejection process and protecting the product's inward buckle structure. The precise fit between the piston 523 and the cylinder 522 ensures a stable gas flow, making the expansion / compression speed of the telescopic airbag 51 controllable, thus solving the problem of product damage caused by sudden speed changes in traditional inclined ejector blocks.

[0061] See also Figure 4-Figure 5 The linkage mechanism 524 includes a rack 5241, a mounting block 5242 and a gear 5243; the rack 5241 is fixed to the ejector plate 3, the mounting block 5242 is fixed to the lower mold 2, the gear 5243 is connected to the mounting block 5242 and rotates around its axis, and a tooth groove 5244 is provided on one side of the ejector rod 521; one side of the gear 5243 is engaged with the rack 5241, and the other side of the gear 5243 is engaged with the ejector rod 521 through the tooth groove 5244.

[0062] It should be noted that when the ejector plate 3 slides upward, it drives the rack 5241 to move upward synchronously, and the rack 5241 engages with the gear 5243 to drive the gear 5243 to rotate; when the gear 5243 rotates, the tooth surface on the other side engages with the tooth groove 5244 of the ejector rod 521, converting the rotational motion into linear motion of the ejector rod 521, thereby driving the piston 523 to slide in the cylinder 522;

[0063] The instantaneous transmission ratio of the rack and pinion meshing transmission is constant and there is no slippage, which ensures the synchronization of the movement of the ejector plate 3 and the ejector rod 521, solves the movement lag problem caused by the gap in the traditional connecting rod transmission, and improves the control accuracy of the telescopic airbag 51; the meshing transmission can realize the flexible conversion of the movement direction, so that when the ejector plate 3 slides upward, it drives the ejector rod 521 to move downward, causing the piston 523 to slide in the cylinder body 522, causing the telescopic airbag 51 to be forced to contract, adapting to the complex demolding trajectory of products with large bevel angles.

[0064] See also Figure 7-Figure 9A plurality of mutually hinged rotating plates 53 are provided on the outside of the telescopic airbag 51; the rotating plates 53 are in contact with the outer wall of the telescopic airbag 51; one of the rotating plates 53 is fixed to the lower mold 2, and a connecting plate 54 is hinged on the other rotating plate 53 away from the rotating plate 53; when the telescopic airbag 51 is expanded, the plurality of rotating plates 53 form a bending structure that is adapted to the inverted inner wall of the injection molded product; the connecting plate 54 is connected to the ejector rod 521; when the ejector rod 521 moves, it is allowed to drive the connecting plate 54 to move, thereby driving the plurality of rotating plates 53 to fold or unfold.

[0065] It should be noted that when the mold is closed, the telescopic airbag 51 expands, pushing the rotating plates 53 hinged to each other on the outside to rotate and unfold around the hinge point. Since the rotating plates 53 close to the lower mold 2 are fixed, the remaining rotating plates 53 gradually form a bending profile adapted to the large-angle inward buckle of the product as the airbag expands, such as the tilt angle and curved surface of the contoured inward buckle, thereby enhancing the forming support of the airbag for the inward buckle of the product; when the mold is opened, the ejector rod 521 pulls the rotating plate 53 at the end through the connecting plate 54, driving all the rotating plates 53 to fold and shrink around the hinge point. At the same time, the telescopic airbag 51 is compressed, providing oblique pulling force for the rotation and folding of the rotating plates 53, so that the rotating plates 53 and the airbag are synchronously separated from the inward buckle of the product to avoid interference;

[0066] The rigid profile formed by the rotating plate 53 can compensate for the problem of insufficient molding precision caused by the excessive flexibility of the telescopic airbag 51, reduce the product's inner buckle dimensional tolerance, and solve the bulging and deformation defects when the airbag is used alone;

[0067] The contact between the rotating plate 53 and the inner buckle of the product is surface contact, rather than the flexible contact of the airbag, which can disperse the demoulding force and prevent the inner buckle of the product from warping due to excessive local force. At the same time, the surface of the rotating plate 53 can be polished to reduce friction damage to the product surface.

[0068] See also Figure 7 and Figure 9 A top plate 55 is fixed on the top rod 521 , and a second spring 56 is provided between the connecting plate 54 and the top plate 55 .

[0069] It should be noted that when the push rod 521 moves, such as when the connecting plate 54 is pulled to fold the rotating plate 53, the second spring 56 is in a stretched or compressed state, and absorbs the instantaneous impact force of the push rod 521 through its own elastic deformation, such as the inertia force when the push rod moves rapidly;

[0070] When the telescopic airbag 51 expands and pushes the rotating plate 53 to unfold, the second spring 56 provides a preload force to ensure that the rotating plate 53 fits tightly against the product and compensates for the pressure fluctuations at the initial stage of airbag expansion.

[0071] The buffering effect of the second spring 56 can reduce the impact force between the rotating plate 53 and the top rod 521, avoid deformation or breakage of the rotating plate 53 due to rigid collision, and extend its service life; the pre-tightening force can eliminate the gap between the rotating plate 53 and the connecting plate 54, ensure the expansion angle accuracy of the rotating plate 53, and further improve the molding consistency of the product's inner buckle.

[0072] See also Figure 7 and Figure 9 The dislocation mechanism 5 also includes an active control mechanism 57, which is used to actively control the air pressure in the telescopic airbag 51; the active control mechanism 57 includes a micro air pump 571 installed on the cylinder body 522, and the output end of the micro air pump 571 is connected to the inside of the telescopic airbag 51 through a connecting tube 572; a pressure sensor is provided in the telescopic airbag 51, and is used to detect the air pressure in the telescopic airbag 51; it can be understood that the pressure sensor is a prior art, and the pressure sensor collects the air pressure data in the telescopic airbag 51 in real time and transmits the data to the mold control system; the control system is a prior art, which is not drawn in the figure and will not be described in detail; the control system automatically adjusts the working state of the micro air pump 571 according to the feedback value of the pressure sensor, forming a closed-loop control of detection-feedback-regulation to ensure that the air pressure in the airbag is stable within the set range.

[0073] It should be noted that during mold closing and injection molding, if the air pressure generated by the piston 523 is insufficient, for example, due to insufficient gas expansion caused by temperature changes, the micro air pump 571 pumps gas into the telescopic airbag 51 through the connecting tube 572 to replenish the air pressure to the set value; during mold opening and demoulding, if the airbag contracts slowly, for example, the gas backflow is not smooth, the micro air pump 571 works in the reverse direction to pump air, accelerating the discharge of gas in the airbag to ensure that it is quickly separated from the product buckle;

[0074] The active control mechanism 57 can make up for the limitations of the passive drive of the piston 523, improve the air pressure control accuracy in the telescopic airbag 51, and solve the problem of insufficient filling or overpressure of the product inner buckle caused by unstable air pressure in traditional passive drive.

[0075] See also Figure 7-Figure 8 The telescopic airbag 51 includes an outer temperature-resistant layer, a middle reinforced fiber mesh, and an inner sealing layer; and the telescopic airbag 51 is made of fluororubber composite material; fluororubber composite material is an existing technology.

[0076] It should be noted that the outer heat-resistant layer of fluororubber substrate can withstand the high temperature during the injection molding process, preventing the airbag from cracking due to thermal aging; the middle layer of reinforced fiber mesh, such as aramid fiber braiding, can improve the tensile strength of the airbag and avoid rupture caused by excessive internal pressure during inflation; the inner sealing layer of fluororubber homogeneous film ensures the airbag's airtightness and maintains stable air pressure;

[0077] The heat resistance and oil resistance of fluororubber composite materials extend its service life; the three-layer structure works synergistically to balance heat resistance, strength and sealing performance, solving the defects of traditional single-material airbags such as resistance to temperature differences, easy rupture and rapid leakage, and adapting to the harsh working conditions of large-angle injection molding.

[0078] Example 2: This example differs from Example 1 in that: Figures 1-10 A precision injection molding method for producing a large-angle injection molded product, including the above-mentioned precision injection mold for producing a large-angle injection molded product, specifically includes the following steps:

[0079] Step 1: Airbag driving: When closing the mold, the driving mechanism 52 drives the telescopic airbag 51 to expand in the forward direction, so that the expansion direction of the telescopic airbag 51 matches the large-angle inward buckling demoulding trajectory, so that the expanded telescopic airbag 51 fits the large-angle inward buckling inner wall of the injection-molded product; when opening the mold, the driving mechanism 52 drives the telescopic airbag 51 to contract in the reverse direction, so that the telescopic airbag 51 contracts and disengages from the inward buckling of the injection-molded product, so that the injection-molded product can be separated from the lower mold 2;

[0080] Step 2: Dynamic adjustment: During the mold closing and injection molding process, the driving force is adjusted in real time by the active control mechanism 57 according to the shrinkage difference of the material, thereby adjusting the expansion degree of the telescopic airbag 51.

[0081] In an optional embodiment: In step 2, the pressure control method of the telescopic airbag 51 is: according to the ambient temperature T and the initial pressure P initial Determine the standard control pressure after temperature correction; specifically, step 1: input parameter definition:

[0082] Input 1: ambient temperature T; unit: K;

[0083] Input 2: Initial pressure P initial ;Unit: kPa;

[0084] Step 2: Determine standard reference conditions:

[0085] Standard temperature: T ref =293.15K

[0086] Standard initial pressure: P ref

[0087] Step 3: Calculate the temperature compensation coefficient:

[0088] According to the ideal gas state equation, pressure is proportional to temperature:

[0089]

[0090] where K T is the temperature compensation coefficient;

[0091] Step 4: Calculate the temperature-corrected pressure:

[0092] Correct the initial pressure to the equivalent pressure at standard temperature:

[0093]

[0094] Step 5: Overlay the standard control pressure offset:

[0095] According to the airbag design specifications, the standard control pressure P standard is the sum of the temperature-corrected pressure and a fixed offset ΔP:

[0096] P standard =P temp_corrected +ΔP

[0097] Where ΔP is the design constant;

[0098] Step 6: Output standard control pressure:

[0099] The final output standard control pressure is:

[0100]

[0101] Unit: kPa.

[0102] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A precision injection mold for producing large-angle injection molded products, comprising an upper mold (1) and a lower mold (2) positioned opposite each other, characterized in that: The bottom of the lower mold (2) is slidably connected to an ejector plate (3) via a guide shaft, and a first spring (4) is provided between the lower mold (2) and the ejector plate (3); a dislocation mechanism (5) is provided on the lower mold (2); the dislocation mechanism (5) comprises: A telescopic airbag (51), wherein a receiving groove is provided on the lower mold (2), and the telescopic airbag (51) is arranged in the receiving groove; when the telescopic airbag (51) is in an expanded state, the telescopic airbag (51) is adapted to the undercut position of the injection molded product; when the telescopic airbag (51) is in a compressed state, the telescopic airbag (51) is allowed to detach from the undercut position of the injection molded product; and a driving mechanism (52), wherein the driving mechanism (52) is arranged on the lower mold (2) and is used to control the expansion or compression of the telescopic airbag (51).

2. A precision injection mold for producing large-angle injection molded products according to claim 1, characterized in that: The driving mechanism (52) comprises a push rod (521), a cylinder (522), a piston (523) and a linkage mechanism (524); the push rod (521) passes through the lower mold (2) and is connected to the ejector plate (3); the cylinder (522) is fixed to the lower mold (2), the piston (523) is slidably connected in the cylinder (522), and the push rod (521) is connected to the piston (523); the linkage mechanism (524) is installed between the ejector plate (3) and the push rod (521); when the ejector plate (3) moves, the linkage mechanism (524) is allowed to drive the push rod (521) to move, thereby driving the piston (523) to slide in the cylinder (522).

3. The precision injection mold for producing large-angle injection molded products according to claim 2, characterized in that: The linkage mechanism (524) includes a rack (5241), a mounting block (5242) and a gear (5243); the rack (5241) is fixed to the ejector plate (3), the mounting block (5242) is fixed to the lower mold (2), the gear (5243) is connected to the mounting block (5242) by rotating around its axis, and a tooth groove (5244) is provided on one side of the ejector rod (521); one side of the gear (5243) is meshed with the rack (5241), and the other side of the gear (5243) is meshed with the ejector rod (521) through the tooth groove (5244).

4. The precision injection mold for producing large-angle injection molded products according to claim 1, characterized in that: A plurality of mutually hinged rotating plates (53) are provided on the outside of the telescopic airbag (51); the rotating plates (53) are in contact with the outer wall of the telescopic airbag (51); one of the rotating plates (53) is fixed to the lower mold (2), and a connecting plate (54) is hinged on another rotating plate (53) away from the rotating plate (53); when the telescopic airbag (51) is expanded, the plurality of rotating plates (53) form a bending structure that is compatible with the undercut inner wall of the injection molded product; the connecting plate (54) is connected to the ejector rod (521); when the ejector rod (521) moves, it is allowed to drive the connecting plate (54) to move, thereby driving the plurality of rotating plates (53) to fold or unfold.

5. The precision injection mold for producing large-angle injection molded products according to claim 4, characterized in that: A top plate (55) is fixedly provided on the top rod (521), and a second spring (56) is provided between the connecting plate (54) and the top plate (55).

6. The precision injection mold for producing large-angle injection molded products according to claim 2, characterized in that: The dislocation mechanism (5) further comprises an active control mechanism (57) for actively controlling the air pressure in the telescopic airbag (51); the active control mechanism (57) comprises a micro air pump (571) mounted on the cylinder body (522), and the output end of the micro air pump (571) is connected to the interior of the telescopic airbag (51) via a connecting pipe (572).

7. The precision injection mold for producing large-angle injection molded products according to claim 6, characterized in that: A pressure sensor is provided in the telescopic airbag (51) and is used to detect the air pressure in the telescopic airbag (51).

8. The precision injection mold for producing large-angle injection molded products according to claim 1, characterized in that: The telescopic airbag (51) comprises an outer temperature-resistant layer, a middle reinforced fiber mesh layer, and an inner sealing layer; and the telescopic airbag (51) is made of a fluororubber composite material.

9. A precision injection molding method for producing large-angle injection molding products, characterized by: The method comprises the following steps: Step 1, airbag driving: when the mold is closed, the telescopic airbag (51) is driven forward by the driving mechanism (52) to expand, so that the expansion direction of the telescopic airbag (51) matches the large-angle inward buckling demoulding trajectory, so that the expanded telescopic airbag (51) fits the large-angle inward buckling inner wall of the injection molded product; when the mold is opened, the telescopic airbag (51) is driven in the reverse direction by the driving mechanism (52) to contract, so that the telescopic airbag (51) contracts and separates from the inward buckling of the injection molded product, so that the injection molded product can be separated from the lower mold (2); Step 2: Dynamic adjustment: During the mold closing and injection molding process, the driving force is adjusted in real time by the active control mechanism (57) according to the shrinkage difference of the material, thereby adjusting the expansion degree of the telescopic airbag (51).

10. The precision injection mold and injection molding method for producing large-angle injection-molded products according to claim 9, characterized in that: In the step 2, the pressure control method of the telescopic airbag (51) is: according to the ambient temperature T and the initial pressure P initial Determine the standard control pressure after temperature correction; specifically, step 1: input parameter definition: Input 1: ambient temperature T; unit: K; Input 2: Initial pressure P initial ; Unit: kPa; Step 2: Determine the standard reference conditions: Standard temperature: T ref =293.15K Standard initial pressure: P ref Step 3: Calculate the temperature compensation coefficient: According to the ideal gas state equation, pressure is proportional to temperature: where K T is the temperature compensation coefficient; Step 4: Calculate the temperature-corrected pressure: Correct the initial pressure to the equivalent pressure at standard temperature: Step 5: Overlay the standard control pressure offset: According to the airbag design specifications, the standard control pressure P standard is the sum of the temperature-corrected pressure and a fixed offset ΔP: P standard =P temp_corrected +ΔP Where ΔP is the design constant; Step 6: Output standard control pressure: The final output standard control pressure is: Unit: kPa.

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