A wet compression molding method and mold

Abstract

The present application discloses a wet moulding method and a mould, the wet moulding method is executed by the wet moulding mould, before the moulding step is executed, the following steps are sequentially executed: preparing a multilayer piece, the multilayer piece includes composite fiber layers and polymer porous layers which are stacked in sequence and cut into plane, and the polymer porous layer is located in the middle layer or the uppermost layer of the multilayer piece; the multilayer piece is transferred to the mould; the resin paste is covered on the surface of the multilayer piece; the method inserts a layer of polymer porous layer in the uppermost layer or the middle layer of the stacked composite fiber layers, the resin paste is absorbed by the polymer porous layer, the flowability of the resin paste is improved, the impregnation degree of the composite fiber layer is increased, and the technical problems that when the single fiber grid dry cloth or the unidirectional dry cloth is used to stack the fiber layer, it is difficult to realize the automatic flow leveling and sufficient impregnation of the resin in the limited coating time are solved.

Description

Technical Field

[0001] This invention relates to the field of wet molding, and more specifically to a wet molding method and mold. Background Technology

[0002] The wet molding process involves cutting dry fiber cloth, spraying it with resin, and then placing it into a mold. It is then cured and molded by heating and holding pressure. The resin paste impregnation process typically takes 20-30 seconds, with most of the time spent by a robot or manual pouring the resin paste onto the surface of the fiber layer. Therefore, the resin paste impregnation time is relatively short, and there are significant differences in the impregnation time of fiber cloth located in different layers in the thickness direction.

[0003] When layering fiber layers using a single fiber mesh dry cloth or unidirectional dry cloth, it is difficult to achieve automatic resin leveling and full impregnation within a limited coating time. This results in uneven color patches appearing on the surface after the product has cured. Areas where the resin is directly applied during coating and fully impregnated have better color, while areas where the resin is not directly in contact with the coating and is not fully impregnated show through the fiber layer's color, resulting in poor surface quality. Summary of the Invention

[0004] The purpose of this invention is to provide a wet molding method and mold to solve the technical problem that the adsorption capacity of a single fiber mesh dry cloth or unidirectional dry cloth is insufficient, and the resin cannot be fully impregnated within the limited coating time in the wet molding process.

[0005] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution:

[0006] A wet molding method, prior to performing the molding step, sequentially performs the following steps: preparing a multilayer part, the multilayer part comprising a composite fiber layer and a polymer porous layer stacked in sequence and cut, wherein the polymer porous layer is located in the middle layer or the top layer of the multilayer part; transferring the multilayer part into a mold; and covering the surface of the multilayer part with resin paste.

[0007] Furthermore, the composite fiber layer is a glass fiber mesh dry cloth, the polymer porous layer is a non-woven fabric, the resin paste is a thermosetting resin base, and the intermediate layer is a second layer.

[0008] Further, the step of preparing the multilayer part includes: cutting the composite fiber layer and the polymer porous layer into shapes that conform to the mold, and stacking them into a plane in a predetermined order to form the multilayer part; or, stacking the composite fiber layer and the polymer porous layer into a plane in a predetermined order to form the multilayer part, and then cutting the multilayer part into shapes that conform to the mold.

[0009] Furthermore, the wet molding method is performed using a wet molding die, which includes: a die frame, an upper die, a lower die, a lower die base, and an elastic reset member. The lower die base and the die frame are fixedly connected, and the lower die is vertically slidably connected to the die frame. The lower die and the lower die base are connected through the elastic reset member. The lower die has several vertically penetrating ejector pin holes and a gas channel connecting each ejector pin hole. The gas channel passes through the lower die and connects to a vacuum pump. The lower die base is connected to a lower ejector pin that is inserted into each ejector pin hole. When the elastic reset member is in a springback state, the tip of the lower ejector pin is located on the side of the gas channel away from the lower die cavity. When in contact with the lower mold base, the gas channel is cut off by the side wall of the lower ejector pin, and the top surface of the lower ejector pin is smoothly connected to the inner wall of the lower mold cavity; the molding step includes: heating the mold so that the temperature inside the mold cavity reaches the temperature for resin curing; evacuating the air between the multilayer part and the lower mold cavity to increase the fluidity of the resin paste moving towards the lower mold cavity; closing the mold, and then evacuating the air between the multilayer part and the upper mold cavity; pressurizing so that the lower mold and the lower mold base are in contact, and the top surface of the lower ejector pin passes through the gas channel and is flush with the inner wall of the lower mold cavity; when the pressure inside the mold cavity reaches the pressure for resin curing, stopping the pressurization and holding the pressure until the product is cured.

[0010] A wet molding die includes: a mold frame, an upper mold, a lower mold, a lower mold base, and an elastic reset member; the lower mold base and the mold frame are fixedly connected, the lower mold is vertically slidably connected to the mold frame, the lower mold and the lower mold base are connected through the elastic reset member, the lower mold has a plurality of vertically penetrating ejector pin holes and a gas channel connecting each ejector pin hole, the gas channel penetrating the lower mold, and a lower ejector pin inserted into each ejector pin hole is connected to the lower mold base; when the elastic reset member is in a springback state, the top end of the lower ejector pin is located on the side of the gas channel away from the lower mold cavity, when the lower mold and the lower mold base are in contact, the gas channel is cut off by the side wall of the lower ejector pin, and the top surface of the lower ejector pin is smoothly connected to the inner wall of the lower mold cavity.

[0011] Furthermore, observation cavities are formed on both sides of the ejector pin hole. The observation cavities are located between the lower mold cavity and the gas channel. The emitter and receiver of a through-beam photoelectric sensor are respectively installed inside the two observation cavities. The observation cavities are connected to the ejector pin hole through an observation channel. A light-transmitting plate is installed at the part of the observation channel that connects to the ejector pin hole. The light-transmitting plate is flush with the inner wall of the ejector pin hole. The emitter is used to emit a light beam that can pass through the two light-transmitting plates and be received by the receiver.

[0012] Furthermore, the light-transmitting plate is made using resin paste of the same material and color as the resin paste in the mold.

[0013] Furthermore, an observation cavity is formed on one side of the ejector pin hole. The observation cavity is located between the lower mold cavity and the gas channel. An ultrasonic sensor is installed inside the observation cavity. The observation cavity is connected to the ejector pin hole through an observation channel. The observation channel is filled with a resin block formed by cured resin. The surface of the resin block is flush with the inner wall of the through hole.

[0014] Furthermore, the resin block is made using a resin paste of the same material as the resin paste in the mold.

[0015] Furthermore, the observation chamber is connected to the gas channel through a wiring hole, which is used for wiring.

[0016] Compared with the prior art, this application has the following advantages:

[0017] A wet molding method and mold are provided. In this method, a polymer porous layer is inserted into the top or middle layer of multiple composite fiber layers. The polymer porous layer adsorbs the resin paste, thereby improving the fluidity of the resin paste and increasing the wetting degree of the composite fiber layers. This solves the technical problem that it is difficult to achieve automatic leveling and full wetting of the resin within a limited coating time when stacking fiber layers using a single fiber mesh dry cloth or unidirectional dry cloth. Attached Figure Description

[0018] To more clearly illustrate the embodiments of the present invention or the technical solutions in 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 merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0019] Figure 1 This is a structural diagram of the product of Embodiment 1 of the present invention;

[0020] Figure 2 This is a perspective view of the lower mold of Embodiment 2 of the present invention;

[0021] Figure 3 This is a cross-sectional view of a working condition of the mold according to Embodiment 2 of the present invention, showing the working condition of vacuuming inside the mold;

[0022] Figure 4 This is a cross-sectional view of another working condition of the mold in Embodiment 2 of the present invention, showing the working condition of solidification and molding inside the mold;

[0023] Figure 5 This is a structural diagram of one working condition of Embodiment 3 of the present invention, showing the working condition of vacuuming inside the mold;

[0024] Figure 6 This is a structural diagram of another working condition in Embodiment 3 of the present invention, showing the working condition of solidification and molding inside the mold;

[0025] Figure 7 This is a structural diagram of Embodiment 4 of the present invention, showing the working condition of vacuuming inside the mold;

[0026] The labels in the diagram represent the following:

[0027] 1-Multi-layer component; 11-Glass fiber mesh dry cloth; 12-Non-woven fabric; 2-Mold; 21-Mold base; 22-Upper mold; 23-Lower mold; 231-Ejector pin hole; 232-Gas channel; 233-Observation cavity; 234-Observation channel; 235-Wire hole; 24-Lower mold base; 241-Lower ejector pin; 25-Elastic reset component; 26-Through-beam photoelectric sensor; 27-Light-transmitting plate; 28-Ultrasonic sensor; 29-Resin block. Detailed Implementation

[0028] 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.

[0029] Because the adsorption capacity of a single fiber mesh dry cloth or unidirectional dry cloth is insufficient, the resin cannot be fully impregnated within the limited coating time in the wet molding process. Even if a large amount of resin paste is poured out of the mold, the underlying fiber layer cannot be fully impregnated. Problems such as material shortage and air holes will occur in the incompletely impregnated areas.

[0030] To address this technical problem, a wet molding method is provided below.

[0031] Example 1, please refer to Figure 1 .

[0032] The wet molding method includes the following steps:

[0033] S1a, the glass fiber mesh dry cloth 11 and the non-woven cloth 12 are cut into the same shape and stacked into a plane in a prescribed order to form a multi-layer piece 1, wherein the non-woven cloth 12 is located in the middle layer or the top layer of the multi-layer piece 1.

[0034] or,

[0035] S1b, the glass fiber mesh dry cloth 11 and non-woven cloth 12 are stacked into a plane in a specified order to form a multi-layer piece 1, wherein the non-woven cloth 12 is located in the middle layer or the top layer of the multi-layer piece 1, and then the multi-layer piece 1 is cut.

[0036] S2, transfer the multi-layer part 1 into mold 2;

[0037] S3, spray, coat or pour resin paste onto the multilayer part 1 so that the resin paste covers the surface of the multilayer part 1;

[0038] S4, sequentially execute the processes of heating mold 2, mold closing, vacuuming, pressurizing and holding pressure to cure the resin into shape;

[0039] S5, open the mold and remove the product.

[0040] When designing the laminate, only the glass fiber content and mechanical performance requirements need to be considered. The nonwoven fabric 12 does not affect the overall thickness of the product or the test results of the glass fiber content.

[0041] Taking a 1.5mm thick thin-walled part as an example, four layers of 400FAM glass fiber mesh dry cloth 11 are used, with a layer of 40-60FAM spunlace nonwoven fabric 12 interspersed in the middle. The 12 layers of nonwoven fabric are preferably placed on the top or second layer, so as to contact and absorb the resin paste more quickly, thereby improving the fluidity of the resin paste. This can greatly solve the problems of inconsistent surface color, material shortage, and air holes caused by the stacking of single-type reinforcing fiber dry cloth.

[0042] Other advantages are: Nonwoven fabric 12 has a wide range of color options, and different colors of nonwoven fabric 12 can be selected for products of different colors. Therefore, when nonwoven fabric 12 is laid on the surface of the reinforcing fiber layer, it has the strongest effect on improving the uniformity of color of the finished product.

[0043] In Example 1:

[0044] Resin pastes can be made from all thermosetting resins, including epoxy resins, polyurethane resins, etc.

[0045] The glass fiber mesh dry cloth 11 can be replaced by commonly available composite fiber materials, such as glass fiber, carbon fiber, aramid fiber, etc., or combinations of carbon fiber and fiber, or combinations of aramid fiber and carbon fiber, etc.

[0046] The arrangement of multi-layer fibers is not limited to the combination of continuous mesh weaving and chopped fiber layers in Example 1. Different weaving types of fibers and chopped fibers of different lengths can be substituted and combined to meet different material performance requirements.

[0047] Nonwoven fabric 12 can be replaced by other polymer porous materials, as long as it can be processed into a layered shape to quickly absorb resin paste, and does not affect the overall thickness of the product or the test results of glass fiber content.

[0048] Example 2, please refer to Figure 2 , 3 4.

[0049] Based on Example 1, the fluidity of the resin paste can be further improved by modifying the mold 2. A wet molding mold 2 is provided below.

[0050] The wet molding die 2 includes: a mold frame 21, an upper mold 22, a lower mold 23, a lower mold base 24, and an elastic reset member 25;

[0051] The lower mold base 24 and the mold frame 21 are fixedly connected. The lower mold 23 is vertically slidably connected to the mold frame 21. The lower mold 23 and the lower mold base 24 are connected by an elastic reset member 25. The lower mold 23 has a number of vertically penetrating ejector pin holes 231 and a gas channel 232 connecting each ejector pin hole 231. The gas channel 232 passes through the lower mold 23 and is connected to a vacuum pump. The lower mold base 24 is connected to a lower ejector pin 241 that is inserted into each ejector pin hole 231.

[0052] When the elastic reset member 25 is in the springback state, the top end of the lower ejector pin 241 is located on the side of the gas channel 232 away from the cavity of the lower mold 23. When the lower mold 23 and the lower mold base 24 are in contact, the gas channel 232 is cut off by the side wall of the lower ejector pin 241, and the top surface of the lower ejector pin 241 is smoothly connected to the inner wall of the cavity of the lower mold 23.

[0053] The advantages of Example 2 are:

[0054] Before molding, air is drawn between the multilayer part 1 and the lower mold cavity 23 through several ejector pin holes 231 and gas channels 232, which can increase the fluidity of the resin paste moving toward the lower mold cavity 23 and further improve the speed at which the glass fiber mesh dry cloth 11 is impregnated by the resin paste.

[0055] During the molding process, the bottom surface of the product is supported by the lower ejector pin 241. During the vacuuming process, the resin paste that overflows into the ejector pin hole 231 is scraped off by the lower ejector pin 241 and ejected into the interior of the glass fiber mesh dry cloth 11, further increasing the diffusion rate of the resin paste.

[0056] The elastic reset member 25 includes a spring and a bolt. The bolt is used to fix the lower mold base 24 and slide the upper mold base 22 to limit the maximum height of the upper mold base 22. The spring is used to abut against the upper mold 22 and the lower mold base 24 to abut the upper mold 22 against the bolt head by its own elastic force.

[0057] The bolts and vacuum pump are not shown in the diagram, nor are the following structures shown:

[0058] The upper mold 22 and lower mold 23 are also provided with heat transfer oil channels, which are used to circulate heat transfer oil to heat the mold 2, so that the mold 2 is heated to the temperature at which the thermosetting resin can be cured and molded; the lower mold 23 is equipped with a temperature sensor, which is used to detect the temperature of the upper mold 22 and lower mold 23; the lower mold 23 is equipped with a pressure sensor, which is used to detect whether the pressure inside the mold cavity has reached the pressure for resin curing; the upper mold 22 has an independent gas channel 232, which is connected to a vacuum pump, which is used to draw air from inside the mold cavity; the lower mold 23 has an overflow groove formed on its edge, into which the resin paste overflowing during molding flows; the upper mold 22 is equipped with an upper ejector pin, which is used to eject the product downwards when the mold is opened.

[0059] The above structures are all common in molding dies, and their specific shapes will not be discussed in this article.

[0060] The wet molding method of Example 2 includes the following steps:

[0061] S41, Heat mold 2 so that the temperature inside the mold cavity reaches the temperature for resin curing and molding;

[0062] S42, draw out the air between the multilayer part 1 and the lower mold cavity 23 to increase the fluidity of the resin paste moving toward the lower mold cavity 23;

[0063] S43, mold closing, air suction between multi-layer part 1 and upper mold cavity 22;

[0064] S44, pressurize, so that the lower mold 23 and the lower mold base 24 come into contact, and the top surface of the lower ejector pin 241 passes through the gas channel 232 and is flush with the inner wall of the cavity of the lower mold 23.

[0065] S45, when the pressure inside the mold cavity reaches the pressure required for resin curing, stop applying pressure and maintain pressure until the product is cured and formed.

[0066] After the mold is opened and the product is removed, the edges of the lower ejector pin 241 and the upper ejector pin will leave marks on the upper and lower surfaces of the product. The marks can be removed by polishing the surface of the product later.

[0067] In Embodiment 2, as long as the axial length of the ejector pin hole 231 is long enough and the distance between the gas channel 232 and the top of the ejector pin hole 231 is large enough, the problem of resin paste entering the gas channel 232 and causing the gas channel 232 to be blocked can be avoided during the brief 10-20 seconds of vacuuming between the suction multilayer part 1 and the lower mold cavity 23.

[0068] However, the axial length of the ejector pin hole 231 is equal to the thickness of the mold 2. The longer the axial length of the ejector pin hole 231, the thicker the mold 2, and the higher the cost of the mold 2. In order to reduce the cost of the mold 2, it is necessary to accurately control the depth of the resin paste entering the ejector pin hole 231 and stop sucking the air inside the gas channel 232 before the resin paste enters the gas channel 232.

[0069] To achieve the above objectives, a preferred embodiment is provided below.

[0070] Example 3, please refer to Figure 5 , 6 .

[0071] Observation cavities 233 are formed on both sides of the ejector hole 231. The observation cavities 233 are located between the lower mold cavity 23 and the gas channel 232. The emitter and receiver of the through-beam photoelectric sensor 26 are respectively installed inside the two observation cavities 233. The observation cavities 233 are connected to the ejector hole 231 through the observation channel 234. A light-transmitting plate 27 is installed at the part of the observation channel 234 that connects to the ejector hole 231. The light-transmitting plate 27 is flush with the inner wall of the ejector hole 231. The emitter is used to emit a light beam that can pass through the two light-transmitting plates 27 and be received by the receiver.

[0072] When the inside of the through-hole is clean, the light beam emitted by the transmitter can pass through the two light-transmitting plates 27 and be received by the receiver.

[0073] When the resin paste enters the interior of the through hole and covers the light-transmitting plate 27, the light beam emitted by the transmitter is scattered by the resin paste after passing through one light-transmitting plate 27 and cannot be received by the receiver through the second light-transmitting plate 27.

[0074] At this time, the vacuum pump stops working, the mold 2 begins to be pressurized, the top surface of the lower ejector pin 241 passes through the gas channel 232 and is flush with the inner wall of the lower mold 23 cavity, the resin paste inside the through hole is scraped off by the lower ejector pin 241, and the inside of the resin paste is cleaned after the mold is opened.

[0075] The light-transmitting plate 27 is preferably made of glass, which has high light transmittance and is hard and wear-resistant. However, the surface of the light-transmitting plate 27 is repeatedly adhered with resin paste and scraped off by the edge of the lower ejector pin 241. After long-term use, the surface of the light-transmitting plate 27 is easily scratched, causing scattering of the light beam passing through the light-transmitting plate 27.

[0076] To solve this problem, preferably, the light-transmitting plate 27 uses the same material and color as the resin paste in the mold 2.

[0077] Some of the resin paste has good light transmittance, and the light beam emitted by the through-beam photoelectric sensor 26 can pass through the light-transmitting plate 27 made of resin paste.

[0078] When the surface of the light-transmitting plate 27 is scratched and pitted, the resin paste flows onto the surface of the light-transmitting plate 27. Excess resin paste is scraped off by the edge of the lower ejector pin 241. Some resin paste remains in the scratches and pits on the surface of the light-transmitting plate 27. When the product is cured and formed, this part of the resin paste is also cured and formed at the same time, thereby repairing the scratches and pits on the surface of the light-transmitting plate 27 and achieving the effect of automatic repair.

[0079] When the resin paste used in the product has low light transmittance, the through-beam photoelectric sensor 26 can be replaced with an ultrasonic sensor 28. Ultrasonic waves can pass through the opaque resin paste plate and detect changes on the other side of the plate, such as when it is covered by resin paste. In this case, an observation cavity 233 can be omitted.

[0080] Example 4, please refer to Figure 7 .

[0081] An observation cavity 233 is formed on one side of the ejector pin hole 231. The observation cavity 233 is located between the lower mold cavity 23 and the gas channel 232. An ultrasonic sensor 28 is installed inside the observation cavity 233. The observation cavity 233 is connected to the ejector pin hole 231 through the observation channel 234. The observation channel 234 is filled with a resin block 29 formed by cured resin. The surface of the resin block 29 is flush with the inner wall of the through hole.

[0082] The ultrasonic sensor 28 is used to emit ultrasonic waves. When the ultrasonic waves reach the interface between the resin block 29 and the air inside the through hole, they are significantly reflected to form a reflected echo, which enables the ultrasonic sensor 28 to detect the thickness of the resin block 29 in the direction of ultrasonic wave propagation. When the resin paste covers the surface of the resin block 29, the thickness of the resin in the direction of ultrasonic wave propagation increases, which causes the signal generated by the ultrasonic sensor 28 to change.

[0083] In Example 4, the resin block 29 and the resin paste in the mold 2 can be made of the same material. Scratches and pits on the surface of the resin block 29 can also be automatically repaired by the resin paste. Furthermore, the resin block 29 and the resin paste do not need to be the same color.

[0084] In embodiments 3 and 4, the observation cavity 233 is connected to the gas channel 232 through the wiring hole 235. The wiring of the ultrasonic sensor 28 and the through-beam photoelectric sensor 26 passes through the wiring hole 235 and the gas channel 232 in sequence and exits the interior of the lower mold 23. A T-junction can be installed at the end of the gas channel 232. One end of the T-junction is used to connect to the vacuum pump, and the other end of the T-junction is used to pass through the wiring.

[0085] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its spirit and scope of protection, and such modifications or equivalent substitutions should also be considered as falling within the scope of protection of the embodiments of the present invention.

Claims

1. A wet molding method, characterized in that, Before performing the molding step, perform the following steps in sequence: Prepare a multilayer component, the multilayer component comprising a composite fiber layer and a polymer porous layer stacked in sequence and cut, wherein the polymer porous layer is located in the middle layer or the top layer of the multilayer component; Transfer the multi-layered component into the mold; A resin paste is applied to the surface of the multilayer component; The wet molding method is performed using a wet molding die, which includes a die frame, an upper die, a lower die, a lower die base, and an elastic reset member. The lower die base and the die frame are fixedly connected, and the lower die is vertically slidably connected to the die frame. The lower die and the lower die base are connected through the elastic reset member. The lower die has several vertically penetrating ejector pin holes and a gas channel connecting each ejector pin hole. The gas channel passes through the lower die and connects to a vacuum pump. The lower die base is connected to a lower ejector pin that is inserted into each ejector pin hole. When the elastic reset member is in a springback state, the top end of the lower ejector pin is located on the side of the gas channel away from the lower die cavity. When the lower die and the lower die base are in contact, the gas channel is cut off by the side wall of the lower ejector pin, and the top surface of the lower ejector pin is smoothly connected to the inner wall of the lower die cavity. The molding step includes: The mold is heated so that the temperature inside the mold cavity reaches the temperature at which the resin cures and is molded. Air is drawn out between the multilayer component and the lower mold cavity to increase the fluidity of the resin paste as it moves toward the lower mold cavity; Close the mold, and then evacuate the air between the multi-layered parts and the upper mold cavity; Pressurization causes the lower mold and the lower mold base to contact each other, and the top surface of the lower ejector pin passes through the gas channel and is flush with the inner wall of the lower mold cavity; When the pressure inside the mold cavity reaches the pressure required for resin curing, stop applying pressure and maintain the pressure until the product is cured and formed.

2. The wet molding method according to claim 1, characterized in that, The composite fiber layer is a glass fiber mesh dry cloth, the polymer porous layer is a non-woven fabric, the resin paste is a thermosetting resin base, and the intermediate layer is a second layer.

3. The wet molding method according to claim 1, characterized in that, The steps for preparing the multilayer component include: The composite fiber layer and the polymer porous layer are cut into shapes that fit the mold and stacked into a plane in a prescribed order to form the multilayer part; Alternatively, the composite fiber layer and the polymer porous layer are stacked in a predetermined order to form a multilayer component, which is then cut into a shape that conforms to the mold.

4. A wet molding die, characterized in that... ， Using the wet molding method according to claim 1, the wet molding die includes: a mold frame (21), an upper mold (22), a lower mold (23), a lower mold base (24), and an elastic reset member (25). The lower mold base (24) and the mold frame (21) are fixedly connected. The lower mold (23) is vertically slidably connected to the mold frame (21). The lower mold (23) and the lower mold base (24) are connected by the elastic reset member (25). The lower mold (23) has a plurality of vertically penetrating ejector pin holes (231) and a gas channel (232) connecting each ejector pin hole (231). The gas channel (232) penetrates the lower mold (23). The lower mold base (24) is connected to a lower ejector pin (241) that is inserted into each ejector pin hole (231). When the elastic reset member (25) is in the springback state, the top end of the lower ejector pin (241) is located on the side of the gas channel (232) away from the cavity of the lower mold (23). When the lower mold (23) and the lower mold base (24) are in contact, the gas channel (232) is cut off by the side wall of the lower ejector pin (241), and the top surface of the lower ejector pin (241) is smoothly connected to the inner wall of the cavity of the lower mold (23).

5. A wet molding die according to claim 4, characterized in that, Observation chambers (233) are formed on both sides of the ejector hole (231). The observation chambers (233) are located between the lower mold (23) cavity and the gas channel (232). The emitter and receiver of the through-beam photoelectric sensor (26) are respectively installed inside the two observation chambers (233). The observation chambers (233) are connected to the ejector hole (231) through the observation channel (234). A light-transmitting plate (27) is installed at the part of the observation channel (234) that connects to the ejector hole (231). The light-transmitting plate (27) is flush with the inner wall of the ejector hole (231). The emitter is used to emit a light beam that can pass through the two light-transmitting plates (27) and be received by the receiver.

6. A wet molding die according to claim 5, characterized in that, The light-transmitting plate (27) is made of resin paste of the same material and color as the resin paste in the mold (2).

7. A wet molding die according to claim 4, characterized in that, An observation cavity (233) is formed on one side of the ejector pin hole (231). The observation cavity (233) is located between the lower mold (23) cavity and the gas channel (232). An ultrasonic sensor (28) is installed inside the observation cavity (233). The observation cavity (233) is connected to the ejector pin hole (231) through an observation channel (234). The observation channel (234) is filled with a resin block (29) formed by cured resin. The surface of the resin block (29) is flush with the inner wall of the through hole.

8. A wet molding die according to claim 7, characterized in that, The resin block (29) is made of resin paste made of the same material as the resin paste in the mold (2).

9. A wet molding die according to any one of claims 5-7, characterized in that, The observation chamber (233) is connected to the gas channel (232) through a wiring hole (235), which is used for wiring.

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