A forming jig suitable for thermally curing liquid silicone
By using a combination of positioning pins and magnets in the thermosetting liquid silicone encapsulation fixture, the problem of cumbersome assembly and disassembly of the upper and lower molds was solved, achieving precise mold closing and stable disassembly, improving production efficiency and reducing costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHONGQING YUNTONG CAR CORE ELECTRONIC TECH CO LTD
- Filing Date
- 2025-05-27
- Publication Date
- 2026-06-05
AI Technical Summary
In the current thermosetting liquid silicone encapsulation process, the upper and lower molds of the molding fixture are connected by screws, which makes disassembly and assembly cumbersome and uneven, and is prone to skewing and leakage, affecting production efficiency and cost.
The design employs a combination of positioning pins and magnets. The positioning pins are used for precise alignment, while the magnets are used to stably attract the upper and lower molds, ensuring accurate and tight mold closing. During disassembly and assembly, the magnetic attraction force is reduced to achieve easy disassembly.
It improves the accuracy and stability of mold closing between the upper and lower molds, reduces the difficulty of disassembly and assembly, reduces the risk of liquid silicone leakage, improves production efficiency and reduces costs.
Smart Images
Figure CN224323422U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of jig technology, and in particular to a molding jig suitable for thermosetting liquid silicone. Background Technology
[0002] IGBTs (Insulated Gate Bipolar Transistors) and MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) are two commonly used semiconductor switching devices in the field of power electronics, playing important roles in a variety of applications. To improve the thermal shock resistance of IGBT / MOSFET single-transistor power devices, thermosetting liquid silicone is generally used instead of plastic encapsulation for encapsulation. Thermosetting liquid silicone can enhance the thermal shock resistance of power devices.
[0003] However, this thermosetting liquid silicone requires 30 minutes of heating at 120 degrees Celsius to cure, so it cannot be injection molded like traditional plastic sealing. When encapsulating, the product to be sealed needs to be placed in the molding fixture for positioning and installation, and then the liquid silicone is poured in. After that, the fixture and the product to be sealed are placed in an oven for curing.
[0004] The molding fixture consists of an upper mold and a lower mold. When placing the product to be sealed, the screws on the upper and lower molds need to be removed, the sealed product needs to be taken out, and then the product to be sealed needs to be installed. Although an electric screwdriver is used to assist in the process, this connection method is still very cumbersome and inefficient. At the same time, when installing several screws on the upper and lower molds, the preload of several screws installed on the upper or lower molds is inconsistent, which makes it easy for the upper and lower molds to be misaligned after they are closed. This can lead to leakage when liquid silicone is poured in. Moreover, after repeatedly tightening the screws, the threads on the upper and lower molds are prone to stripping, which can lead to the failure of the connection between the upper and lower molds. Utility Model Content
[0005] To address the shortcomings of existing technologies, this utility model provides a molding fixture suitable for thermosetting liquid silicone, which solves the problem that the assembly and disassembly of the upper and lower molds is cumbersome when screws are used for assembly and disassembly.
[0006] To achieve the above objectives, the basic solution of this utility model is as follows: A molding fixture suitable for thermosetting liquid silicone, comprising an upper mold and a lower mold, and further comprising:
[0007] Several positioning pins are installed on the upper or lower mold, and the upper or lower mold is provided with pin holes for the positioning pins to be inserted.
[0008] Several magnets are mounted on the upper or lower mold, and the magnets can attract the upper or lower mold.
[0009] The technical principle of this utility model is as follows: When the upper and lower molds are closed, the positioning pins and pin holes make the alignment and installation of the upper and lower molds more precise. After precise positioning, the upper surface of the lower mold and the lower surface of the upper mold approach each other, and the magnetic attraction force acts on the upper or lower mold, so that the closing surfaces of the lower and upper molds quickly and tightly adhere to each other. At this time, the attraction force of several magnets acts evenly on the upper or lower mold, so that the upper and lower molds fit stably and evenly, which can effectively avoid the skewing of the upper and lower molds after they are closed and reduce the risk of leakage when liquid silicone is poured in.
[0010] When disassembling the upper and lower molds, it is only necessary to separate the upper and lower molds to reduce the attraction force of the magnets on the upper or lower molds. This greatly reduces the difficulty of disassembling and assembling the upper and lower molds, thereby improving production efficiency and reducing production costs.
[0011] Furthermore, the locating pin is an open, flexible cylindrical pin.
[0012] With the above settings, when the open elastic cylindrical pin is installed into the pin hole, the open part at the end of the open elastic cylindrical pin can be easily inserted into the pin hole, improving installation efficiency; at the same time, the end of the open elastic cylindrical pin has a certain elasticity, which can adapt to the slight deviation between the pin hole and the open elastic cylindrical pin, reducing the difficulty of initially inserting the open elastic cylindrical pin into the pin hole.
[0013] Furthermore, the cross-sectional profile of the pin hole is circular or strip-shaped, and the outer wall of the locating pin is clearance-fitted with the inner wall of the pin hole.
[0014] With the above settings, the pin hole with a strip-shaped cross-section can perform preliminary positioning of the upper and lower molds when it is engaged with the positioning pin; the pin hole with a circular cross-section can perform precise positioning of the upper and lower molds when it is engaged with the positioning pin, so that the upper and lower molds can be quickly aligned and closed, combining pre-positioning and precise positioning to improve the efficiency of precise mold closing of the upper and lower molds.
[0015] Furthermore, the roughness Ra of the lower surface of the upper mold and the upper surface of the lower mold are the same, with a roughness Ra of 1.5-3 μm.
[0016] The above settings ensure reliable sealing after the lower surface of the mold fits snugly against the upper surface of the lower mold.
[0017] Furthermore, the lower mold has a mounting hole on the side near the upper mold for embedding and installing a magnet, and the end face of the magnet near the upper mold is lower than the upper surface of the lower mold.
[0018] With the above settings, when separating the upper and lower molds, since the upper surface of the magnet is lower than the lower surface of the lower mold, it is ensured that the upper mold will not pull the magnet out when separating the upper and lower molds; at the same time, it is ensured that when the upper and lower molds are closed, the magnet's attraction force on the upper mold is sufficient to ensure that the upper and lower molds are tightly connected without leakage of liquid silicone.
[0019] Furthermore, a separation hole communicating with the mounting hole is provided at the bottom of the lower mold mounting hole, and the separation hole is opposite to the side of the magnet away from the upper mold.
[0020] With the above setup, when the magnet's attraction weakens, the magnet can be knocked out of the mounting hole through the separation hole on the lower mold, making it easy to replace the magnet.
[0021] Furthermore, the Curie point of the magnet is higher than the curing temperature of the liquid silicone.
[0022] With the above settings, since the Curie point of the magnet is higher than the curing temperature of the liquid silicone, the magnet can still ensure a reliable connection between the upper and lower molds at the curing temperature of the liquid silicone, allowing the liquid silicone on the product to be sealed to be precisely cured and molded.
[0023] Furthermore, the upper side of the lower mold and the lower side of the upper mold are joined together to form a molding cavity, and several sprues and risers communicating with the molding cavity are provided on one side of both the lower mold and the upper mold; some locating pins are set between two adjacent sprues and risers.
[0024] With the above settings, since some positioning pins are set between two adjacent risers and gating points, the risers and gating points can be accurately positioned and assembled after the lower mold and upper mold are closed, making the injection of liquid silicone precise.
[0025] Furthermore, several magnets are evenly arranged around the circumference of the molding cavity, and positioning pins are located between the magnets.
[0026] With the above setup, several magnets can uniformly and stably attract the lower and upper molds circumferentially, making the mold closing of the lower and upper molds stable.
[0027] Furthermore, a first opening is provided on the side wall of the lower mold near the edge of the upper mold, and a second opening is provided on the side wall of the upper mold near the edge of the lower mold. The first opening can be combined with the second opening.
[0028] With the above setup, when disassembling the upper and lower molds, the operator can attach their hands to the first and second hand openings to remove the upper mold from the lower mold, separating the positioning pin from the pin hole. The setup of the first and second hand openings makes it easier for the operator to apply force and increases the disassembly efficiency. Attached Figure Description
[0029] Figure 1 This is a schematic diagram of the axial side structure of a molding jig suitable for thermosetting liquid silicone after mold closing, according to an embodiment of the present invention.
[0030] Figure 2 This is a schematic diagram of the disassembled structure of a molding fixture suitable for thermosetting liquid silicone in an embodiment of this utility model.
[0031] Figure 3 This is an exploded view of the structure of a molding fixture suitable for thermosetting liquid silicone.
[0032] Figure 4 This is a schematic diagram of the upper and lower molds of a molding fixture suitable for thermosetting liquid silicone after removing the locating pins and magnets.
[0033] In the above figures: lower mold 10, first access port 101, mounting hole 102, separation hole 103, upper mold 20, second access port 201, pin hole 202, molding cavity 30, gating gate 40, positioning pin 50, magnet 60. Detailed Implementation
[0034] The technical solution of this utility model will be further described below with reference to the accompanying drawings and embodiments.
[0035] This embodiment is basically as follows: Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown in the figure, this utility model embodiment proposes a molding fixture suitable for thermosetting liquid silicone, including an upper mold 20, a lower mold 10, two positioning pins 50 and four magnets 60. Both the upper mold 20 and the lower mold 10 are made of mold steel. The lower left side wall and the upper right side wall of the lower mold 10 are provided with a first hand opening 101. The upper and lower side walls of the first hand opening 101 are arc-shaped transitions with the side walls of the lower mold 10. The lower left side wall and the upper right side wall of the upper mold 20 are provided with a second hand opening 201. The upper and lower side walls of the second hand opening 201 are arc-shaped transitions with the side walls of the upper mold 20. The first hand opening 101 can be completely assembled with the second hand opening 201.
[0036] like Figure 2 and Figure 4 As shown, the upper parting surface of the lower mold 10 and the lower parting surface of the upper mold 20 are joined together to form a molding cavity 30. The molding cavity 30 is located at the center of the upper mold 20 and the lower mold 10. Both the lower mold 10 and the upper mold 20 are provided with two sprues 40 that communicate with the molding cavity 30 on the upper left side. At the same time, the roughness Ra of the lower surface of the upper mold 20 and the upper surface of the lower mold 10 is the same, and the roughness Ra is 1.5-3μm.
[0037] like Figure 2 and Figure 3 As shown, four magnets 60 are evenly arranged around the circumference of the forming cavity 30. The four magnets 60 are located at the four corners of the upper mold 20 and the lower mold 10, respectively. The magnets 60 can attract the upper mold 20. The two positioning pins 50 are both open elastic cylindrical pins. The two positioning pins 50 are located between the two magnets 60 on the left and the two magnets 60 on the right. The positioning pin 50 on the left is located between the two sprues 40 on the left.
[0038] At the same time, such as Figure 2 and Figure 3 As shown, the lower mold 10 has a mounting hole 102 on the side near the upper mold 20 for embedding and installing a magnet 60. The end face of the magnet 60 near the upper mold 20 is lower than the upper surface of the lower mold 10. The bottom of the mounting hole 102 of the lower mold 10 has a separation hole 103 communicating with the mounting hole 102. The separation hole 103 is opposite to the lower end face of the magnet 60. The positioning pin 50 is installed on the lower mold 10. The lower surface of the upper mold 20 has two pin holes 202 for inserting the positioning pin 50. The pin holes 202 penetrate the upper mold 20. The cross-sectional profile of the left pin hole 202 is circular, and the cross-sectional profile of the right pin hole 202 is strip-shaped. The outer wall of the positioning pin 50 is clearance-fitted with the inner wall of the pin hole 202, with a clearance of 0.03-0.7mm.
[0039] In addition, the Curie point of magnet 60 is greater than 310°C, which is higher than the curing temperature of liquid silicone.
[0040] In this embodiment, a molding fixture suitable for thermosetting liquid silicone is used by first separating the upper mold 20 and the lower mold 10. When separating the upper mold 20 and the lower mold 10, the operator puts their hands on the first hand opening 101 and the second hand opening 201 to remove the upper mold 20 from the lower mold 10. The positioning pin 50 separates from the pin hole 202. During this process, since the upper surface of the magnet 60 is lower than the lower surface of the lower mold 10, it is ensured that the upper mold 20 will not pull the magnet 60 out when the upper mold 20 and the lower mold 10 are separated. At the same time, it is ensured that when the upper mold 20 and the lower mold 10 are closed, the attraction force of the magnet 60 on the upper mold 20 is sufficient to make the upper mold 20 and the lower mold 10 tightly connected without leakage of liquid silicone.
[0041] Then, the product to be sealed is placed into the molding cavity 30 of the lower mold 10, and the upper mold 20 and the lower mold 10 are closed. During the mold closing process, the positioning pin 50 is first inserted into the pin hole 202. The pin hole 202, with a strip-shaped cross-sectional profile, can perform preliminary positioning of the upper mold 20 and the lower mold 10 when it cooperates with the positioning pin 50. The pin hole 202, with a circular cross-sectional profile, can accurately position the upper mold 20 and the lower mold 10 when it cooperates with the positioning pin 50, so that the upper mold 20 and the lower mold 10 can be quickly aligned and closed, and the upper mold 20 can also be closed more quickly. The gate and riser 40 on the lower mold 10 are precisely aligned; at the same time, when the upper surface of the lower mold 10 and the lower surface of the upper mold 20 approach each other, the attraction force of the surrounding magnets 60 acts on the upper mold 20, so that the mold-closing surfaces of the lower mold 10 and the upper mold 20 quickly and tightly close together. Since the roughness value of the lower surface of the mold and the upper surface of the lower mold 10 are both "", the upper surface of the lower mold 10 and the lower surface of the upper mold 20 can fit tightly together, which can effectively prevent the upper mold 20 and the lower mold 10 from being misaligned after mold closing, and reduce the risk of leakage when pouring liquid silicone.
[0042] Then, liquid silicone is poured into the molding cavity 30 through the riser 40. The fixture and the product to be sealed are placed in the oven for curing. During the curing process, since the Curie point of the magnet 60 is higher than the curing temperature of the liquid silicone, the magnet 60 can still ensure a reliable connection between the upper mold 20 and the lower mold 10 at the curing temperature of the liquid silicone, so that the liquid silicone on the product to be sealed can be accurately cured and molded.
[0043] When removing the sealed product from the fixture, the operator once again attaches their hands to the first hand opening 101 and the second hand opening 201, removes the upper mold 20 from the lower mold 10, and then removes the sealed product.
[0044] In the above process, the use of magnetic connection between the upper mold 20 and the lower mold 10 can greatly reduce the difficulty of disassembling and assembling the upper mold 20 and the lower mold 10, thereby improving production efficiency and reducing production costs. Furthermore, the cooperation between the positioning pin 50 and the pin hole 202 makes the upper mold 20 and the lower mold 10 more precise when aligned and installed.
[0045] When the attraction force of magnet 60 weakens, magnet 60 is knocked out of mounting hole 102 through separation hole 103 on lower mold 10, making it easy to replace magnet 60.
[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the spirit and scope of the technical solutions of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.
Claims
1. A molding fixture suitable for thermosetting liquid silicone, comprising an upper mold and a lower mold, characterized in that, Also includes: A plurality of positioning pins are provided, wherein the positioning pins are installed on the upper or lower mold, and the upper or lower mold is provided with pin holes for the positioning pins to be inserted. Several magnets are mounted on an upper or lower mold, and the magnets can attract the upper or lower mold.
2. A molding fixture for thermosetting liquid silicone as described in claim 1, characterized in that, The positioning pin is an open, elastic cylindrical pin.
3. A molding fixture for thermosetting liquid silicone as described in claim 1, characterized in that, The cross-sectional profile of the pin hole is circular or strip-shaped, and the outer wall of the positioning pin is clearance-fitted with the inner wall of the pin hole.
4. A molding fixture for thermosetting liquid silicone as described in claim 3, characterized in that, The roughness Ra of the lower surface of the upper mold and the upper surface of the lower mold is the same, and the roughness Ra is 1.5-3μm.
5. A molding fixture for thermosetting liquid silicone as described in claim 1, characterized in that, The lower mold has a mounting hole on the side near the upper mold for embedding a magnet, and the end face of the magnet near the upper mold is lower than the upper surface of the lower mold.
6. A molding fixture for thermosetting liquid silicone as described in claim 5, characterized in that, The bottom of the lower mold mounting hole is provided with a separation hole that communicates with the mounting hole, and the separation hole is opposite to the side of the magnet away from the upper mold.
7. A molding fixture for thermosetting liquid silicone as described in any one of claims 1-6, characterized in that, The Curie point of the magnet is higher than the curing temperature of the liquid silicone.
8. A molding fixture for thermosetting liquid silicone as described in any one of claims 1-6, characterized in that, The upper side of the lower mold and the lower side of the upper mold are assembled to form a molding cavity. Several sprues and risers communicating with the molding cavity are provided on one side of both the lower mold and the upper mold. Some positioning pins are set between two adjacent sprues and risers.
9. A molding fixture for thermosetting liquid silicone as described in claim 8, characterized in that, Several magnets are evenly arranged around the circumference of the forming cavity, and positioning pins are located between the magnets.
10. A molding fixture for thermosetting liquid silicone as described in claim 8, characterized in that, The lower mold sidewall is provided with a first opening near the edge of the upper mold, and the upper mold sidewall is provided with a second opening near the edge of the lower mold. The first opening can be combined with the second opening.