A limiting device

Abstract

This application relates to the technical field of capacitor auxiliary fixtures, and in particular to a limiting device, including a limiting base, limiting plates, and an auxiliary hole. Two limiting plates are provided, each vertically fixed to the upper surface of the limiting base. The two limiting plates are parallel to each other, forming a limiting space between them. This limiting space is used to accommodate an unsealed die assembly. The distance between the outer surfaces of the two limiting plates is consistent with the width of the sealed shell after sealing. The width of the limiting plates is greater than the thickness of the sealed shell. The auxiliary hole penetrates the thickness direction of the limiting base and is located in the central region between the two limiting plates. This application has the effect of limiting the die assembly position within a specified range to assist manual spot welding, ensuring that the thickness of the sealed shell is within an allowable range during sealing.

Description

Technical Field

[0001] This application relates to the technical field of capacitor auxiliary fixtures, and in particular to a limiting device. Background Technology

[0002] Tantalum capacitors are among the best capacitors due to their small size and large capacitance, exhibiting excellent performance. This type of capacitor offers diverse form factors, making it particularly suitable for surface mount technology, and can be manufactured into miniaturized and chip-sized components. Tantalum capacitors have a wide range of applications, not only in high-end fields such as military communications and aerospace, but also in various industries including industrial automation control, film and television equipment, communication equipment, and instrumentation.

[0003] The domestic consumer tantalum capacitor market is currently dominated by imported products, indicating a huge potential for domestic substitution. This product mainly consists of three core components: chip assembly, epoxy resin, and lead frame. In terms of manufacturing processes, most domestic manufacturers still use traditional manual assembly methods. This method has a significant technical bottleneck: due to the difficulty in precise control during manual operation, chip positioning often cannot be perfectly centered. If this chip misalignment exceeds the allowable range, the thickness of the encapsulated shell will be too thin, falling below the safe range, leading to defects such as missing chips or product cracking, seriously affecting product yield and reliability. Utility Model Content

[0004] To assist manual spot welding and limit the chip mounting position within a specified range, ensuring the thickness of the encapsulation shell remains within permissible limits during encapsulation, this application aims to provide a limiting device. The technical solution adopted is as follows: Includes a limiting base, a limiting plate, and auxiliary holes; Two limiting plates are provided, both of which are vertically fixed to the upper surface of the limiting base. The two limiting plates are parallel to each other, and a limiting space is formed between the two limiting plates. The limiting space is used to accommodate the unsealed chip assembly. The distance between the outer surfaces of the two limiting plates is consistent with the width of the sealed shell after sealing. The width of the limiting plate is greater than the safety range of the sealing thickness. The auxiliary hole extends through the thickness direction of the limiting base and is located in the central region between the two limiting plates.

[0005] By adopting the above technical solution, when workers place the die package on the lead frame for fixation, it ensures that the position of the unsealed die package on the lead frame is limited to a certain range, preventing the die package from shifting. As a result, when the die package and lead frame are subsequently sealed, the thickness of the plastic shell is within the allowable range, preventing defects such as missing cores or product cracking. At the same time, it ensures that the width of the plastic shell is consistent, further improving the molding quality and consistency of the product.

[0006] The two symmetrically arranged limiting plates and support platforms, along with the central auxiliary hole, form a stable and symmetrical support structure. The parallel limiting plates ensure the lateral positioning accuracy of the object to be limited (such as a lead frame), the support platform provides support force, and the auxiliary hole facilitates manual spot welding of the product. The overall structure is simple and highly integrated.

[0007] Optionally, it also includes a support platform, wherein there are two support platforms, both fixed to the upper surface of the limiting base and located between the two limiting plates; the two support platforms are symmetrically arranged on both sides of the auxiliary hole.

[0008] By adopting the above technical solution, the stability of the limiting device and its support effect on the lead frame are further enhanced. The support platform can lift the lead frame and prevent it from bending, sagging or deforming within the limiting space due to its own weight or external pressure. Especially for thinner or more fragile lead frames, the symmetrical layout ensures a balanced distribution of support force and avoids encapsulation defects caused by uneven force.

[0009] Optionally, the two limiting plates, the two support platforms, and the auxiliary holes constitute a set of limiting units, and multiple sets of the limiting units are arranged on the limiting base along its extension direction.

[0010] By adopting the above technical solution, the modular arrangement design of multiple sets of limiting units significantly improves the space utilization and batch processing capacity of the device. By repeatedly configuring the same units along the extension direction of the base, multiple workpieces (such as core block assemblies) can be fixed simultaneously, greatly improving production efficiency, and is especially suitable for continuous automated production lines.

[0011] Optionally, a limiting space is formed between the two limiting plates in the limiting unit, and the limiting space is used to accommodate the chip assembly.

[0012] By adopting the above technical solution, the directional accommodation function of the limiting space for the core assembly ensures that the workpiece maintains a precise position during processing or transportation. The physical boundary formed by the limiting plate directly constrains the lateral movement of the workpiece, reducing the risk of displacement and improving process stability and product consistency.

[0013] Optionally, the height of the limiting plate is greater than the height of the support platform, and the top of the limiting plate is also higher than the upper surface of the core block assembly.

[0014] By adopting the above technical solution, the height of the limiting plate exceeds the setting of the support platform and the core block assembly, thus forming a protective barrier in the vertical direction. This design effectively prevents external collisions or vibrations from causing the workpiece to fall out of the limiting space, enhancing the reliability of the device in dynamic environments.

[0015] Optionally, the upper surface of the support platform is provided with an anti-slip structure.

[0016] By adopting the above technical solution, the anti-slip structure (such as texture or coating) on ​​the surface of the support table significantly increases the coefficient of friction with the workpiece. By suppressing the horizontal sliding of the workpiece on the support table, stability after precise positioning is ensured, which is especially suitable for high vibration or tilting conditions.

[0017] Optionally, the upper surface of the support platform abuts against the lead frame, and a suspended area is formed between the upper surface of the limiting base and the bottom of the lead frame.

[0018] By adopting the above technical solution, the partial contact design between the support platform and the lead frame creates a suspended area between the base surface and the bottom of the frame. This structure avoids large-area contact between the frame and the base. During spot welding and silver paste bonding, excess silver paste may overflow and fall onto the limiting base. The suspension prevents the silver paste from sticking to the product, which would make detachment inconvenient.

[0019] Optionally, the projection of the auxiliary hole is located directly below the bottom overhang area of ​​the chip assembly, and the overhang area is connected to the auxiliary hole.

[0020] By adopting the above technical solution, the vertical connection between the auxiliary hole and the suspended area creates a through-channel. This structure allows workers to directly and conveniently spot weld the workpiece through the auxiliary hole without having to flip the workpiece before spot welding. It also prevents the workpiece from shifting due to flipping, which would reduce product yield and production efficiency.

[0021] Optionally, an isolation plate is provided between the adjacent limiting units, and the isolation plate is arranged in a direction perpendicular to the extension direction of the limiting base.

[0022] By adopting the above technical solution, the addition of the isolation plate achieves physical separation between adjacent limiting units. This design effectively prevents interference between different workstations (such as thermoforming during subsequent encapsulation, where adjacent units may affect each other due to temperature), improving the independence and safety of parallel processing of multiple workpieces.

[0023] In summary, this application includes at least one of the following beneficial technical effects: 1. When workers place the die package on the lead frame for fixation, it ensures that the position of the unsealed die package on the lead frame is limited within a certain range, preventing the die package from shifting. This ensures that the thickness of the plastic sealant is within the allowable range when the die package and lead frame are subsequently sealed, preventing defects such as missing die or product cracking. At the same time, it ensures that the width of the plastic sealant is consistent, further improving the molding quality and consistency of the product. 2. By designing the core structure as a repeatable limiting unit along the base, the device achieves modular expansion, significantly improving space utilization and batch processing capacity to meet the needs of continuous production. The added isolation plates between units effectively isolate adjacent workstations, preventing interference (such as chip movement or operational errors), and ensuring the independence and operational safety of parallel processing of multiple workpieces. 3. The anti-slip structure on the support surface further enhances the workpiece's resistance to displacement on the support surface. Meanwhile, the connection between the auxiliary holes and the bottom overhang area ensures that workers can spot weld the workpiece through the auxiliary holes without having to flip it over for re-spot welding. This also prevents workpiece displacement caused by flipping, which could reduce product yield. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of the limiting device; Figure 2 This is a schematic diagram of the overall structure of the limiting device and the lead frame; Figure 3 This is a side view of the limiting device, lead plate, and core assembly. Figure 4 This is a schematic diagram of the capacitor structure after plastic sealing; In the picture, 1. Limiting base; 2. Limiting plate; 3. Auxiliary hole; 4. Support platform; 5. Lead wire frame; 51. Lead wire plate; 52. Lead wire frame; 53. Limiting hole; 6. Chip assembly; 61. Tantalum wire; 7. Isolation board 8. Plastic-sealed outer casing. Detailed Implementation

[0025] The following is in conjunction with the appendix Figure 1 - Appendix Figure 4 This application will be described in further detail below.

[0026] A limiting device, as shown in the reference Figure 1The device includes a limiting base 1, limiting plates 2, auxiliary holes 3, and a support platform 4. The limiting base 1 is a cuboid shape with a flat upper surface. This base serves as the basic support platform for the entire device. Two rectangular limiting plates 2 are vertically fixed to the upper surface of the limiting base 1. The two limiting plates 2 are parallel to each other, and their inner surfaces (i.e., the two opposite faces) constitute the main lateral limiting surfaces. The limiting plates 2 can be fixed by welding, bolting, or other mechanical connections to ensure that the limiting plates 2 are firmly positioned on the limiting base 1.

[0027] A limiting space is formed between the two limiting plates 2. The limiting space is used to accommodate the unsealed chip package 6. The distance between the outer surfaces of the two limiting plates 2 is consistent with the width of the plastic-sealed shell 8 after sealing. The width of the limiting plates 2 is greater than the safe range of the sealing thickness. During subsequent sealing, it can be ensured that the thickness of the plastic-sealed shell is within the safe range.

[0028] On the limiting base 1, in the central area between the two limiting plates 2, two auxiliary holes 3 are formed along the thickness direction (i.e., vertical direction) of the limiting base 1, and these holes completely penetrate the limiting base 1. On the upper surface of the limiting base 1, within the area between the two limiting plates 2, two support platforms 4 are fixedly installed. The two support platforms 4 are symmetrically arranged with respect to the auxiliary holes 3, specifically located on both sides of the auxiliary holes 3. The upper surface of the support platforms 4 is used to directly support the work object being limited. The fixing method can also be welding.

[0029] When the worker places the chip assembly 6 on the lead frame 5 for fixation, it ensures that the position of the unsealed chip assembly 6 on the lead frame 5 is limited to a certain range, preventing the chip assembly 6 from shifting. As a result, when the chip assembly 6 and the lead frame 5 are subsequently sealed, the thickness of the plastic casing 8 is within the allowable range, and there will be no defects such as missing cores or product cracking. At the same time, it ensures that the width of the plastic casing 8 is consistent, further improving the molding quality and consistency of the product.

[0030] Furthermore, refer to Figure 1 Two limiting plates 2, two support platforms 4, and auxiliary holes 3 constitute a limiting unit. Multiple sets of limiting units are evenly arranged on the limiting base 1 along its extension direction. An isolation plate 7 is provided between adjacent limiting units, and its surface is arranged in a direction perpendicular to the length of the limiting base 1. Since the capacitor product will be plastic-encapsulated in the end, and the plastic-encapsulation method is thermoplastic, thermoplastic technology is a core technology in materials science for processing thermoplastic plastics. It softens and shapes the plastic by heating, and then sets it after cooling. The isolation plate 7 is to prevent adjacent core modules 6 from interfering with each other.

[0031] Furthermore, refer to Figure 2Between the two parallel limiting plates 2, a limiting space is formed to accommodate the chip assembly 6. This space constrains the movement of the chip assembly 6 in the horizontal direction, ensuring its positional accuracy. The top of the limiting plate 2 is significantly higher than the upper surface of the chip assembly 6 (e.g., 1-3 mm higher), forming an impact-resistant protective barrier to prevent external operation from damaging the chip assembly 6.

[0032] Furthermore, refer to Figure 2 and Figure 3 The upper surface of the support platform 4 directly supports the lead frame 5, and the height of the support platform 4 is lower than that of the adjacent limiting plate 2. The lead frame 5 includes a lead plate 51 and a lead frame 52. The lead plate 51 is connected to the lead frame 52. The chip assembly 6 is located above the lead plate 51. There are two lead plates 51, and the chip assembly 6 is located on one of the lead plates 51. The lead plate 51 supporting the chip assembly 6 is folded into a Z-shape to support the chip assembly 6. One end of the chip assembly 6 is inserted with a tantalum wire 61. The end of the other lead plate 51 will then be attached to the tantalum wire 61. The attached part is spot-welded to fix the tantalum wire 61 to the lead plate 51. The lead plate 51 supporting the chip assembly 6 needs to be glued and fixed with silver paste because silver has the best conductivity and will not affect the internal conductivity of the electronic product.

[0033] The lead frame 5 is provided with a limiting hole 53. The size of the limiting hole 53 is the same as that of the limiting plate 2. When the lead frame 5 is placed on the limiting device, the limiting plate 2 will be inserted into the limiting hole 53 accordingly. Therefore, the lead frame 5 will be limited by the limiting plate 2, which can prevent the lead plate 51 from shifting when processing the lead plate 51 and the core block assembly 6.

[0034] Furthermore, refer to Figure 2 In order to facilitate spot welding and bonding of the chip assembly 6 and the lead plate 51, an auxiliary hole 3 is made through the limiting base 1, so that workers can spot weld and bond directly from below without flipping the product. This prevents the workpiece from shifting due to flipping, which would reduce product yield and production efficiency.

[0035] Furthermore, refer to Figure 3 Because the upper surface of the support platform 4 abuts against the lead frame 5, a suspended area is formed between the upper surface of the limiting base 1 and the bottom of the lead plate 51. The projection of the auxiliary hole 3 is located directly below the suspended area at the bottom of the chip assembly 6, and the suspended area is connected to the auxiliary hole 3. This gap avoids friction damage between the frame and the base, provides operating space for welding and bonding processes, and promotes heat dissipation. At the same time, when bonding with silver paste, the silver paste will overflow and easily drip onto the limiting base 1. The suspended design prevents the silver paste that falls onto the limiting base 1 from sticking to the product, making it impossible to separate the product in the end.

[0036] Reference Figure 3 and Figure 4 After the spot welding and bonding processes are completed, the product is encapsulated using epoxy resin. After encapsulation, a fully encapsulated shell is formed on the core assembly 6. At this time, part of the two lead plates 51 are outside the shell. This part of the lead plate 51 is bent to fit against the outer surface of the shell. The lead plate 51, which is fixedly connected to the tantalum wire 61 by spot welding, forms the anode terminal of the capacitor, while the lead plate 51 at the other end forms the cathode terminal of the capacitor.

[0037] The overall process involves first placing the lead frame 5 on the support platform 4, then inserting the limiting plate 2 into the limiting hole 53 on the lead frame 5, with the limiting plate 2 and the limiting hole 53 corresponding in size. Next, the chip assembly 6 is placed on the lead plate 51 of the lead frame 5, and the lead plate 51 is bent so that the end of the tantalum wire 61 on the chip assembly 6 contacts another lead plate 51. The chip assembly 6 and the lead plate 51 are then bonded and spot-welded through the auxiliary hole 3 below, thus fixing the chip assembly 6 and the lead plate 51 together. During bonding and spot welding, the limiting plate 2 ensures that the chip assembly 6 remains between the two limiting plates 2, preventing significant displacement. The thickness of the two limiting plates 2 exceeds the safe range of the encapsulation thickness after molding, which is the distance between the edge of the inner chip assembly 6 and the outer surface of the encapsulated shell 8. Then, the lead frame 5 is removed and encapsulated. During encapsulation, the width of the encapsulated shell is determined by the distance between the outer sides of the two limiting holes 53. That is, the distance between the encapsulated shell and the outer surface of the two limiting plates 2 is consistent, ensuring the consistency of product size. At the same time, it also ensures that the thickness of the encapsulated shell 8 is within a safe range, and there will be no quality problems such as core leakage or product cracking.

[0038] The implementation principle of this application embodiment is as follows: the lead frame 5 is placed on the support platform 4, the core block 6 is placed on the lead frame 5, its side is constrained by the positioning plate 2, and its bottom is suspended. The core block 6 and the lead plate 51 are spot welded and bonded with silver paste through the auxiliary hole 3, thereby fixing the two together. The suspended area ensures that the process is free from interference. Then the lead frame 5 is removed and plastic-sealed, the lead plate 51 is cut off, and finally the lead plate 51 is bent to form the anode and cathode terminals, thus completing the product manufacturing.

[0039] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be covered within the scope of protection of this application.

Claims

1. A position limiting device, characterized by, It includes a limiting base (1), a limiting plate (2), and an auxiliary hole (3); Two limiting plates (2) are provided and both are vertically fixed to the upper surface of the limiting base (1). The two limiting plates (2) are parallel to each other and a limiting space is formed between the two limiting plates (2). The limiting space is used to accommodate the unsealed core module (6). The distance between the outer surfaces of the two limiting plates (2) is consistent with the width of the sealed shell (8) after sealing. The width of the limiting plate (2) is greater than the safety range of the sealing thickness. The auxiliary hole (3) extends through the thickness direction of the limiting base (1) and is located in the central region between the two limiting plates (2).

2. A stop device according to claim 1, wherein It also includes a support platform (4), which has two supports, both of which are fixed to the upper surface of the limiting base (1) and located between the two limiting plates (2); the two support platforms (4) are symmetrically arranged on both sides of the auxiliary hole (3).

3. A stop device according to claim 2, wherein The two limiting plates (2), the two support platforms (4) and the auxiliary hole (3) constitute a set of limiting units, and multiple sets of the limiting units are arranged on the limiting base (1) along its extension direction.

4. A stop device according to claim 3, wherein The height of the limiting plate (2) is greater than the height of the support platform (4), and the top of the limiting plate (2) is also higher than the upper surface of the core block assembly (6).

5. A stop device according to claim 2, wherein The upper surface of the support platform (4) is provided with an anti-slip structure.

6. A stop device according to claim 2, wherein The upper surface of the support platform (4) abuts against the lead frame (5), and a suspended area is formed between the upper surface of the limiting base (1) and the bottom of the lead frame (5).

7. A stop device according to claim 1 or 6, characterised in that The projection of the auxiliary hole (3) is located directly below the bottom suspended area of ​​the core block (6), and the suspended area is connected to the auxiliary hole (3).

8. A stop device according to claim 3, wherein An isolation plate (7) is provided between the adjacent limiting units, and the isolation plate (7) is arranged in a direction perpendicular to the extension direction of the limiting base (1).

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