Injection mold with a feeding function

Abstract

The application discloses an injection mold with a shrinkage compensation function, relates to the technical field of injection molds, and aims to solve the problem of local shrinkage of injection products in the prior art. The injection mold comprises a mold core, a male mold plate, a first shrinkage compensation mechanism, a positioning mechanism and a power mechanism. The first shrinkage compensation mechanism comprises a syringe barrel, a first pressing plate and a second pressing plate, the syringe barrel penetrates through the male mold plate and is inserted into the mold core, and the syringe barrel comprises an outer barrel and an inner needle. A first storage cavity is arranged on the mold core. When an injection part has not completely cooled down during injection, the BOSS column has a shrinkage tendency due to cooling, the power mechanism drives the first pressing plate to move upwards, the outer barrel connected to the first pressing plate moves upwards for shrinkage compensation, the storage material in the first storage cavity below the BOSS column feature flows upwards, the plastic melt inside the BOSS column feature is extruded for shrinkage compensation, and the vacancy caused by shrinkage is effectively compensated.

Description

Technical Field

[0001] This application relates to the field of injection mold technology, and in particular to an injection mold with a shrinkage compensation function. The injection mold significantly improves product quality through precise shrinkage compensation design for BOSS pillars, local corners and thick areas. Background Technology

[0002] Injection molding is a widely used process, but localized shrinkage remains a challenging technological problem. Shrinkage defects easily occur in areas such as bosses, corners, and areas with significant wall thickness due to uneven plastic cooling and shrinkage. Specifically, shrinkage at bosses affects assembly accuracy and fit stability; shrinkage at corners often leads to poor appearance, impacting product aesthetics; and in thicker areas, shrinkage can easily cause product deformation, reducing dimensional accuracy and structural strength, thus directly affecting the overall quality and functionality of the product.

[0003] Current solutions have limitations. Adjusting injection molding parameters, such as increasing holding pressure or extending holding time, can reduce shrinkage to some extent, but the effect is limited and may introduce new problems such as demolding difficulties and warping, while also extending production cycles and increasing costs. Adding reinforcing ribs to the product structure can improve material distribution, but often interferes with appearance or function, and the improvement effect on severely shrunken areas is not significant. In addition, using additional heating devices requires complex temperature control systems, increasing mold costs and energy consumption.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the overall background of this application and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Utility Model Content

[0005] The purpose of this application is to provide an injection mold with a shrinkage compensation function, which is used to compensate for shrinkage in areas of the injection molded part that are prone to shrinkage.

[0006] To achieve the above objectives / to solve the above technical problems, this utility model adopts the following technical solution: An injection mold with a shrinkage compensation function is used to produce injection molded parts. The mold includes: a mold core, a male template, a first shrinkage compensation mechanism, a positioning mechanism, and a power mechanism. The mold core is fastened to the male template, the positioning mechanism is connected to the power mechanism, and the power mechanism is drivenly connected to the first shrinkage compensation mechanism. The first feeding mechanism includes a sleeve, a first pressure plate, and a second pressure plate. The sleeve penetrates the male template and is inserted into the mold core. The sleeve includes an outer cylinder and an inner pin. The outer cylinder is fastened to the first pressure plate, and the inner pin is fastened to the second pressure plate. The mold core is provided with a first material storage cavity, which is located at the BOSS post on the injection molded part. The output end of the outer cylinder is perpendicularly connected to the first material storage cavity, and the inner needle is connected to the inner hole of the BOSS post on the injection molded part.

[0007] The mold core provides space for the molding of the injection molded part. The male and female mold plates are fitted together and installed on the injection molding machine frame. The specific installation method is existing technology in the injection molding field and will not be elaborated here. The first compensation mechanism is used to compensate for the BOSS position on the injection molded part. By setting a first storage cavity on the mold core, a portion of the molten plastic material is stored during the injection molding process to provide a material source for compensation. The inner wall of the first storage cavity is polished to reduce the flow resistance of the molten plastic. Its material is the same as that of the mold body to ensure consistent thermal performance. The ejector sleeve is used to push... The feeding material flows, pushing the material stored in the first storage chamber below the BOSS pillar feature upwards, compressing and feeding the plastic melt inside the BOSS pillar feature. During injection molding, when the injection molded part is not completely cooled, the outer cylinder of the ejector moves upwards to feed, and the feeding amount at this time is very small. After the injection molded part cools to the ejection requirement, the ejector rod on the injection molding machine will push the upper and lower ejector plates. At this time, the first pressure plate and the outer cylinder pressed in the upper and lower ejector plates will be ejected upwards again, this time ejecting the injection molded part, and the ejection distance at this time is larger.

[0008] Furthermore, the positioning mechanism includes an upper ejector plate, a lower ejector plate, and a lower fixing plate. The first pressure plate is fastened to the upper ejector plate, the lower ejector plate is fastened to the upper ejector plate, and the lower fixing plate is fastened to the second pressure plate.

[0009] The upper ejector plate and the lower ejector plate are used to fix the first pressure plate, and the lower fixing plate is used to fix the second pressure plate, so that the first pressure plate located in the upper ejector plate and the lower ejector plate and the second pressure plate located on the lower fixing plate can move independently, thereby allowing the outer cylinder and the inner needle to move independently.

[0010] Furthermore, the power mechanism includes a solenoid valve, a piston rod, and a cylinder. The piston rod is slidably connected to the cylinder. The solenoid valve is equipped with an intake pipe and an outlet pipe, which are respectively connected to the intake port and outlet port on the cylinder. The piston rod is drivenly connected to the first pressure plate.

[0011] The solenoid valve is the core control component of the power mechanism. Its core function is to control the flow direction of compressed air through electrical signals, guiding the airflow to the cylinder through the inlet and outlet pipes, thereby driving the piston rod to move according to preset logic, realizing the automation function of the mold. A solenoid valve with fast response speed and high reliability should be selected, and its rated flow rate should meet the air intake requirements of the cylinder. The piston rod is installed in the cylinder and moves upward under the push of the gas, driving the first pressure plate, thereby compressing the material stored in the first storage chamber at the top of the outer cylinder, realizing the feeding action.

[0012] Furthermore, the solenoid valve is equipped with an air inlet and outlet, which are connected to an external air source.

[0013] The air source serves as the power source to drive the power mechanism.

[0014] Furthermore, the clearance between the piston rod and the cylinder is controlled between 0.02 and 0.05 mm.

[0015] The piston rod and cylinder body require high precision in their fit, employing a clearance fit with the clearance controlled within 0.02-0.05mm to ensure sealing performance and prevent leakage of the molten plastic. Wear-resistant and high-temperature-resistant PTFE (polytetrafluoroethylene) reinforced composite material is selected to improve service life.

[0016] Furthermore, the cylinder body is equipped with fixed feet, which are fastened to the cylinder plate on the positioning mechanism.

[0017] The cylinder plate mates with the fixed feet to fix and position the cylinder body.

[0018] Furthermore, the ejector sleeve is perpendicular to the bottom surface of the mold core, and the molding position deviation between the ejector sleeve and the BOSS pillar on the injection molded part is controlled within ±0.05mm.

[0019] The ejector sleeve must be made of high-strength, wear-resistant mold steel, such as SKD61 (medium carbon high chromium alloy tool steel), to withstand the high pressure and friction during injection molding; its inner and outer diameters must be precisely designed according to the size of the BOSS pillar. During installation, ensure that the ejector sleeve is perpendicular to the bottom surface of the mold core and precisely corresponds to the BOSS pillar forming position, with the deviation controlled within ±0.05mm.

[0020] Furthermore, the injection mold also includes a second shrinkage compensation mechanism, which includes an ejector pin and a slanted pin. The mold core is also provided with a second material storage cavity, which is located at the thick part of the injection molded part. The ejector pin is connected to the power mechanism for transmission, and the output end of the ejector pin abuts against the second material storage cavity. The slanted pin abuts against the thick corner of the injection molded part.

[0021] The second shrinkage compensation mechanism is used to compensate for the thicker parts of the injection molded part. The second sump is used to store a portion of the molten plastic material during the injection molding process, providing a material source for shrinkage compensation. During shrinkage compensation, the ejector pin moves upward under the drive of the power mechanism, squeezing the molten plastic in the second sump towards the thicker parts of the injection molded part, thereby compressing them. The size of the second sump is determined by the shrinkage volume estimated in the previous mold flow analysis results, and its specific shape is customized according to the designable space on the mold for local corners or thicker parts of the product. The inner wall of the second sump is polished to reduce the flow resistance of the molten plastic, and its material is the same as that of the mold body to ensure consistent thermal performance. During the molding process of the second sump, there are some lateral structural features, and the inclined pin can provide a lateral horizontal core-pulling action.

[0022] Furthermore, the tilt angle of the slanted pin is within 3-6°.

[0023] The inclined pin will move upward along a specific inclined direction. The inclination angle and direction of the inclined pin are determined by the size of the second storage cavity and the distance of the product ejected from the mold cavity after molding. Generally speaking, the inclination angle of the inclined pin is within 3~6° to ensure that after the inclined pin is pulled out, it is about 2mm away from the second storage cavity. This ensures that the product can be demolded smoothly, and also ensures the integrity and accuracy of the shape of the second storage cavity.

[0024] Compared with the prior art, the beneficial effects achieved by this application are as follows: 1. By setting a first storage cavity on the mold core, a portion of the molten plastic material is stored during the injection molding process to provide a material source for shrinkage compensation. During injection molding, when the molded part has not been completely cooled, the BOSS pillar tends to shrink due to cooling contraction. The power mechanism drives the first pressure plate to move upward, causing the outer cylinder connected to the first pressure plate to move upward to compensate for shrinkage. This pushes the material stored in the first storage cavity below the BOSS pillar feature to flow upward, compressing and compensating the molten plastic inside the BOSS pillar feature. This molten plastic flows along the ejector sleeve and accurately fills the interior of the BOSS pillar, effectively making up for the voids caused by shrinkage and ensuring the integrity of the BOSS pillar's appearance and structure.

[0025] 2. For complex areas prone to shrinkage, such as corners or thicker sections of injection molded parts, a second material storage chamber is specially designed nearby. During injection molding, the second material storage chamber stores an appropriate amount of molten plastic, and an ejector pin is equipped below it. When shrinkage is detected in this area, a solenoid valve controls the piston rod to push the ejector pin upward, squeezing the material stored in the second material storage chamber into the shrinkage area, completing precise shrinkage compensation. This effectively improves the product's appearance quality, ensures product structural stability, and greatly reduces the impact of appearance shrinkage defects on product quality. The cylinder structure composed of the solenoid valve linkage cylinder and piston rod can be adapted to various products for shrinkage compensation by changing the solenoid valve control parameters, such as rise time and speed, and is easy to maintain. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the overall structure of this application; Figure 2 This is a schematic diagram of the power mechanism of this application; Figure 3 This is a schematic diagram of the first compensation mechanism in this application; Figure 4 This is a schematic diagram of the second compensation mechanism in this application.

[0028] In the diagram: 1. Injection part; 2. Mold core; 21. First material storage cavity; 22. Second material storage cavity; 3. Male mold plate; 4. First shrinkage compensation mechanism; 41. Ejector sleeve; 411. Outer cylinder; 412. Inner pin; 42. First pressure plate; 43. Second pressure plate; 5. Positioning mechanism; 51. Upper ejector plate; 52. Lower ejector plate; 53. Lower fixing plate; 54. Cylinder plate; 6. Power mechanism; 61. Solenoid valve; 611. Air inlet and outlet; 62. Piston rod; 63. Cylinder body; 64. Fixed foot; 65. Air inlet pipe; 66. Air outlet pipe; 7. Second shrinkage compensation mechanism; 71. Ejector pin; 72. Angled pin. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its application or use. Example 1

[0030] like Figure 1 , Figure 3 As shown, this embodiment provides an injection mold with a shrinkage compensation function. The injection mold is used to produce injection molded part 1, including: mold core 2, male template 3, first shrinkage compensation mechanism 4, positioning mechanism 5 and power mechanism 6. The mold core 2 is fastened to the male template 3, the positioning mechanism 5 is connected to the power mechanism 6, and the power mechanism 6 is drivenly connected to the first shrinkage compensation mechanism 4. The first shrinkage compensation mechanism 4 includes a sleeve 41, a first pressure plate 42, and a second pressure plate 43. The sleeve 41 penetrates the male template 3 and is inserted into the mold core 2. The sleeve 41 includes an outer cylinder 411 and an inner needle 412. The outer cylinder 411 is fastened to the first pressure plate 42, and the inner needle 412 is fastened to the second pressure plate 43. The mold core 2 is provided with a first material storage cavity 21, which is located at the BOSS post on the injection molded part 1. The output end of the outer cylinder 411 is perpendicularly abutted against the first material storage cavity 21, and the inner needle 412 abuts against the inner hole of the BOSS post on the injection molded part 1.

[0031] The mold core 2 provides space for the molding of the injection molded part 1. The male mold plate 3 and the female mold plate are installed on the injection molding machine frame. The specific installation method is existing technology in the injection molding field and will not be described in detail here. The first shrinkage compensation mechanism 4 is used to compensate for the BOSS pillar position on the injection molded part 1. A first material storage cavity 21 is set on the mold core 2 to store a portion of the molten plastic material during the injection molding process, providing a material source for shrinkage compensation. The inner wall of the first material storage cavity 21 is polished to reduce the flow resistance of the molten plastic. Its material is the same as that of the mold body to ensure consistent thermal performance. The ejector sleeve 41 is used to push the compensation mechanism. The material flow is compressed, pushing the material stored in the first storage chamber 21 below the BOSS column feature to flow upward, compressing and compressing the plastic melt inside the BOSS column feature; during injection molding, when the injection molded part 1 has not been completely cooled, the outer cylinder 411 of the ejector sleeve 41 moves upward to compress, and the amount of compression at this time is very small; when the injection molded part 1 cools to the ejection requirement, the ejector rod on the injection molding machine will push the upper and lower ejector plates, and the first pressure plate 42 and the outer cylinder 411 pressed in the upper and lower ejector plates will be ejected upward again, this time ejecting the injection molded part, and the ejection distance at this time is larger.

[0032] like Figure 1 As shown, the positioning mechanism 5 includes an upper ejector plate 51, a lower ejector plate 52 and a lower fixing plate 53. The first pressure plate 42 is fastened to the upper ejector plate 51, the lower ejector plate 52 is fastened to the upper ejector plate 51, and the lower fixing plate 53 is fastened to the second pressure plate 43.

[0033] The upper ejector plate 51 and the lower ejector plate 52 are used to fix the first pressure plate 42, and the lower fixing plate 53 is used to fix the second pressure plate 43, so that the first pressure plate 42 located in the upper ejector plate 51 and the lower ejector plate 52 and the second pressure plate 43 located on the lower fixing plate 53 can move independently, thereby allowing the outer cylinder 411 and the inner needle 412 to move independently.

[0034] like Figure 2 As shown, the power mechanism 6 includes a solenoid valve 61, a piston rod 62, and a cylinder 63. The piston rod 62 is slidably connected to the cylinder 63. The solenoid valve 61 is provided with an air inlet pipe 65 and an air outlet pipe 66. The air inlet pipe 65 and the air outlet pipe 66 are respectively connected to the air inlet and air outlet on the cylinder 63. The piston rod 62 is drivenly connected to the first pressure plate 42.

[0035] Solenoid valve 61 is the core control element of power mechanism 6. Its core function is to control the flow direction of compressed air through electrical signals, guiding the airflow to cylinder 63 through inlet pipe 65 and outlet pipe 66, thereby driving piston rod 62 to act according to preset logic, realizing the automation function of the mold. A solenoid valve with fast response speed and high reliability should be selected, and its rated flow rate should meet the air intake requirements of cylinder 63. Piston rod 62 is installed in cylinder 63. Under the push of gas, it moves upward to drive the first pressure plate 42, thereby compressing the material stored in the first storage chamber 21 at the top of outer cylinder 411, realizing the feeding action.

[0036] The solenoid valve 61 is provided with an air inlet and outlet port 611, which is connected to an external air source.

[0037] The air source serves as the power source to drive the action of the power mechanism 6.

[0038] The clearance between the piston rod 62 and the cylinder 63 is controlled between 0.02 and 0.05 mm.

[0039] The piston rod 62 and cylinder 63 require high precision in their fit, employing a clearance fit with the clearance controlled within 0.02-0.05mm to ensure sealing performance and prevent leakage of the molten plastic. Wear-resistant and high-temperature-resistant PTFE (polytetrafluoroethylene) reinforced composite material is selected to improve service life.

[0040] The cylinder body 63 is provided with a fixed foot 64, which is fastened to the cylinder plate 54 on the positioning mechanism 5.

[0041] The cylinder plate 54 cooperates with the fixed foot 64 to fix and position the cylinder body 63.

[0042] The ejector sleeve 41 is perpendicular to the bottom surface of the mold core 2, and the molding position deviation between the ejector sleeve 41 and the BOSS pillar on the injection molded part 1 is controlled within ±0.05mm.

[0043] The ejector sleeve 41 must be made of high-strength, wear-resistant mold steel, such as SKD61 (medium carbon high chromium alloy tool steel), to withstand the high pressure and friction during the injection molding process; its inner and outer diameters must be precisely designed according to the size of the BOSS pillar features. During installation, ensure that the ejector sleeve 41 is perpendicular to the bottom surface of the mold core 2 and precisely corresponds to the BOSS pillar forming position, with the deviation controlled within ±0.05mm. Example 2

[0044] like Figure 4As shown, in order to compensate for shrinkage in the thick part of the injection molded part, the injection mold also includes a second shrinkage compensation mechanism 7. The second shrinkage compensation mechanism 7 includes an ejector pin 71 and a slanted pin 72. The mold core 2 is also provided with a second material storage cavity 22, which is located in the thick part of the injection molded part 1. The ejector pin 71 is connected to the power mechanism 6 for transmission. The output end of the ejector pin 71 abuts against the second material storage cavity 22. The slanted pin 72 abuts against the corner thick part of the injection molded part 1.

[0045] The second shrinkage compensation mechanism 7 is used to compensate for the thicker parts of the injection molded part 1. The second storage cavity 22 is used to store a portion of the molten plastic material during the injection molding process to provide a material source for shrinkage compensation. During shrinkage compensation, the ejector pin 71 moves upward under the drive of the power mechanism 6, squeezing the molten plastic in the second storage cavity 22 towards the thicker parts of the injection molded part 1, thereby compressing it. The size of the second storage cavity 22 is determined by the shrinkage volume estimated in the previous mold flow analysis results, and its specific shape is customized according to the designable space on the mold for the local corners or thicker parts of the product. The inner wall of the second storage cavity 22 is polished to reduce the flow resistance of the molten plastic. Its material is the same as that of the mold body to ensure consistent thermal performance. During the molding process of the second storage cavity 22, there are some lateral structural features. The inclined pin 72 can provide a lateral horizontal core-pulling action.

[0046] The tilt angle of the slanted pin 72 is within 3-6°.

[0047] The inclined pin 72 will move upward along a specific inclined direction. The inclination angle and direction of the inclined pin 72 are determined by the size of the second storage cavity 22 and the distance of the product ejected from the mold cavity after molding. Generally speaking, the inclination angle of the inclined pin 72 is within 3~6° to ensure that after the inclined pin 72 is pulled out, it is about 2mm away from the second storage cavity. This ensures that the product can be demolded smoothly, and also ensures the integrity and accuracy of the shape of the second storage cavity 22.

[0048] The working principle of this application: The setting of the first shrinkage compensation mechanism 4 and the second shrinkage compensation mechanism 7 is mainly based on the mold flow analysis results or the actual molding situation. If the mold flow analysis shows that the shrinkage of certain areas of the injection molded part is large, the corresponding shrinkage compensation mechanism will be planned directly in the mold design stage; another case is that no shrinkage compensation mechanism is set in the early stage of mold design, and the shrinkage compensation mechanism is added later according to the shrinkage of the actual molded product after trial molding. During injection molding, when the injection molded part 1 has not been completely cooled, and the BOSS column has a shrinkage tendency due to cooling shrinkage, the solenoid valve 61 is activated, which guides the gas to the cylinder 63. Under the push of the gas, the piston rod 62 moves upward, which in turn moves the first pressure plate 42 upward, so that the outer cylinder 411 connected to the first pressure plate 42 moves upward to compensate for shrinkage, and pushes the material stored in the first storage cavity 21 below the BOSS column feature to flow upward, squeezing and compressing the plastic melt inside the BOSS column feature. This plastic melt flows along the ejector sleeve 41 and accurately fills the inside of the BOSS column, effectively making up for the gaps caused by shrinkage and ensuring The integrity of the appearance and structure of the BOSS column; when compensating for shrinkage in the thick part of the injection molded part 1, the ejector pin 71 moves upward under the drive of the piston rod 62 of the power mechanism 6, squeezing the plastic melt in the second storage chamber 22 towards the thick part of the injection molded part 1, thereby compensating for shrinkage; the first and second shrinkage compensation mechanisms are designed for the characteristics of different easily shrinkable parts of the injection molded part. Whether it is the BOSS column, or all easily shrinkable positions such as local corners and thicker parts, this technology can achieve precise shrinkage compensation, effectively improve the appearance quality of the product, ensure the stability of the product structure, and greatly reduce the impact of appearance shrinkage defects on product quality.

[0049] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to explain the relative positional relationship and movement between components in a specific orientation. If the specific orientation changes, the directional indication will also change accordingly. These terms are used only for the convenience of describing this application and for simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0050] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0051] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art will be able to understand the specific meaning of the above terms in this application based on the specific circumstances.

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

Claims

1. An injection mold with a shrinkage compensation function, the injection mold being used to produce injection molded parts (1), characterized in that, include: The mold core (2), the male template (3), the first shrinkage compensation mechanism (4), the positioning mechanism (5), and the power mechanism (6) are fastened together. The mold core (2) is fastened to the male template (3), the positioning mechanism (5) is connected to the power mechanism (6), and the power mechanism (6) is connected to the first shrinkage compensation mechanism (4) via transmission. The first shrinkage compensation mechanism (4) includes a sleeve (41), a first pressure plate (42), and a second pressure plate (43). The sleeve (41) penetrates the male template (3) and is inserted into the mold core (2). The sleeve (41) includes an outer cylinder (411) and an inner needle (412). The outer cylinder (411) is fastened to the first pressure plate (42), and the inner needle (412) is fastened to the second pressure plate (43). The mold core (2) is provided with a first storage cavity (21), the first storage cavity (21) is located at the BOSS post on the injection molded part (1), the output end of the outer cylinder (411) is perpendicularly abutted against the first storage cavity (21), and the inner needle (412) abuts against the inner hole of the BOSS post on the injection molded part (1).

2. The injection mold with shrinkage compensation function according to claim 1, characterized in that: The positioning mechanism (5) includes an upper ejector plate (51), a lower ejector plate (52) and a lower fixing plate (53). The first pressure plate (42) is fastened to the upper ejector plate (51), the lower ejector plate (52) is fastened to the upper ejector plate (51), and the lower fixing plate (53) is fastened to the second pressure plate (43).

3. The injection mold with shrinkage compensation function according to claim 1, characterized in that: The power mechanism (6) includes a solenoid valve (61), a piston rod (62) and a cylinder (63). The piston rod (62) is slidably connected to the cylinder (63). The solenoid valve (61) is provided with an air inlet pipe (65) and an air outlet pipe (66). The air inlet pipe (65) and the air outlet pipe (66) are respectively connected to the air inlet and air outlet on the cylinder (63). The piston rod (62) is drivenly connected to the first pressure plate (42).

4. An injection mold with shrinkage compensation function according to claim 3, characterized in that: The solenoid valve (61) is provided with an air inlet and outlet (611), and the air inlet and outlet (611) is connected to an external air source.

5. An injection mold with shrinkage compensation function according to claim 3, characterized in that: The clearance between the piston rod (62) and the cylinder (63) is controlled between 0.02 and 0.05 mm.

6. An injection mold with shrinkage compensation function according to claim 3, characterized in that: The cylinder body (63) is provided with a fixed foot (64), which is fastened to the cylinder plate (54) on the positioning mechanism (5).

7. An injection mold with shrinkage compensation function according to claim 1, characterized in that: The ejector sleeve (41) is perpendicular to the bottom surface of the mold core (2), and the molding position deviation between the ejector sleeve (41) and the BOSS pillar on the injection molded part (1) is controlled within ±0.05mm.

8. An injection mold with shrinkage compensation function according to claim 1, characterized in that: The injection mold also includes a second shrinkage compensation mechanism (7), which includes an ejector pin (71) and a slanted pin (72). The mold core (2) is also provided with a second material storage cavity (22), which is located at the thick part of the injection molded part (1). The ejector pin (71) is connected to the power mechanism (6) for transmission. The output end of the ejector pin (71) abuts against the second material storage cavity (22), and the slanted pin (72) abuts against the thick part at the corner of the injection molded part (1).

9. An injection mold with shrinkage compensation function according to claim 8, characterized in that: The tilt angle of the inclined pin (72) is within 3-6°.

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