A structural limiting-based electroless plating batch clamping tool and a method of using the same

Abstract

This invention discloses a chemical plating batch clamping fixture based on structural constraint and its application method, belonging to the field of fixture technology. The fixture includes at least one clamping unit, comprising an upper frame, a lower frame, and isolation columns connecting the upper and lower frames. After assembly via the isolation columns, the upper and lower frames have corresponding hollow structures. The contour of the hollow structures matches the planar projection contour of the workpiece. A sandwich structure exists between the upper and lower frames. Longitudinal and transverse protrusions are provided around the hollow structures to constrain the parts within the hollow structure area. Based on the principle of physical interference, the fixture is highly effective in preventing the flipping of lightweight, small parts, eliminating damage to the parts, and is particularly suitable for precision parts.

Description

Technical Field

[0001] This invention relates to the field of surface treatment tooling technology, specifically a chemical plating batch clamping tool based on structural positioning and its application method. Background Technology

[0002] Chemical plating is a surface treatment technology that uses a reducing agent to autocatalytically reduce and deposit a metal coating on an activated working surface without the application of an external current. During chemical plating, the workpiece needs to be immersed in the plating solution. For small, precision parts (such as electronic components and precision inserts), traditional clamping methods often use metal wires such as iron or copper wires for binding and fixing. This method has the following disadvantages: 1. Low efficiency: Each workpiece needs to be individually bound, which is cumbersome, labor-intensive, and makes it difficult to achieve mass production.

[0003] 2. Workpiece is easily damaged: The metal wire is in rigid contact with the workpiece surface, which can easily scratch the workpiece base at the contact point, resulting in scrap. Secondary damage may also occur during disassembly.

[0004] 3. Difficulty in guaranteeing coating quality: Coating cannot be deposited at the points where the metal wire contacts the workpiece, forming "masking points" that affect the workpiece's corrosion resistance, conductivity, and appearance. Tight binding hinders the flow of the plating solution, leading to uneven coating thickness; lightweight, small parts are prone to flipping or overlapping during plating solution circulation, resulting in missed plating. Furthermore, the metal wire may dissolve and contaminate the plating solution or cause unnecessary deposition in non-plating areas.

[0005] 4. Difficult to automate: The binding process often requires threading the silk into the process hole or binding it around the perimeter, making it difficult to integrate into an automated production line.

[0006] Currently, there are no patents or documents in this field applicable to non-batch clamping and related methods. Although some material frames or hangers exist on the market, most have a crude structure and excessive space, failing to effectively restrict the flipping of small parts; others employ complex clamping mechanisms, which suffer from high costs, easy damage to workpieces, and the formation of obstruction points. Therefore, there is an urgent need to develop a clamping solution that can efficiently, non-damagingly, and reliably fix small parts without affecting the coating quality. Summary of the Invention

[0007] The purpose of this invention is to provide a clamping fixture and method to solve the technical problems of traditional binding methods, such as low operating efficiency, easy damage to workpieces, poor coating uniformity, existence of obstruction points, and easy displacement of small parts, while avoiding the use of complex clamping elements.

[0008] A chemical plating batch clamping fixture based on structural constraint includes at least one clamping unit. The clamping unit includes an upper frame, a lower frame, and a separation column connecting the upper and lower frames. After the upper and lower frames are assembled via the separation column, the upper and lower frames have corresponding hollow structures. The outline of the hollow structure matches the planar projection outline of the workpiece. There is a sandwich between the upper and lower frames. Longitudinal and transverse protrusions are provided around the hollow structure to constrain the parts within the hollow structure area. The sandwich thickness H satisfies 1.05T < H ≤ 1.15T, where T is the thickness of the part.

[0009] Furthermore, the upper and lower frames are provided with isolation column connection holes. The isolation column is a round rod that is pressed into the corresponding holes of the upper and lower frames by interference fit.

[0010] Furthermore, the upper frame and the lower frame are respectively provided with card blocks or card sleeves, which are connected and fixed to each other.

[0011] Furthermore, the clamping unit has several groups, and adjacent clamping units are connected by clips or sleeves on the upper and lower frames.

[0012] Furthermore, the isolation column has threads, and the interlayer thickness H can be adjusted by adjusting the fixed position with a nut.

[0013] Furthermore, the clamping unit has a handle.

[0014] Furthermore, the clamping unit has a base underneath, and the base has several through holes.

[0015] The present invention also provides a method for using a chemical plating batch clamping fixture based on structural positioning. Using the aforementioned fixture, the workpiece is placed into the interlayer space. Relying on the interlayer space having a fitting gap with the workpiece, the workpiece floats in the interlayer space under the impact of the plating solution and is thus fixed.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. Simple structure and high reliability: The tooling does not contain vulnerable or complex clamping components, has a simple structure, low cost, low failure rate, and long service life; 2. Stable clamping and prevention of overturning: The tooling is based on the principle of physical interference, which has a very significant effect on preventing the overturning of lightweight and small parts, eliminating damage to the parts, and is especially suitable for precision parts. 3. Non-destructive clamping: The tooling and workpiece are fitted with a micro-clearance, eliminating point and line contact pressure and completely avoiding scratches on the workpiece surface during clamping and disassembly. 4. High-quality coating: The open cage structure ensures that the plating solution can flow, circulate and renew itself without any obstruction around and between the workpieces, without any obstruction points, thus obtaining an extremely uniform chemical coating; the tooling is made of corrosion-resistant insulating material, which will not contaminate the plating solution or cause chemical deposition in non-target areas. 5. High-efficiency batch clamping: The modular and layered design allows for the clamping of dozens or even hundreds of workpieces at a time, making it convenient to pick up and put down, and suitable for mass production and automated production. Attached Figure Description

[0017] Figure 1 This is a three-dimensional structural diagram of a single clamping unit of the present invention; Figure 2 This is a schematic diagram showing the lower frame after the parts have been placed inside. Figure 3 This is a schematic diagram of the overall clamping fixture after multiple clamping units are stacked; Figure 4 yes Figure 3 Exploded view; Figure 5 This is a schematic diagram of the principle of the present invention, illustrating the relationship between the workpiece thickness T and the clearance on one side; Figure 6 This is a schematic diagram of a single layer of the upper frame; Figure 7 This is a schematic diagram of the card sleeve and card block of the present invention; Figure 8 This is a schematic diagram of the structure of a separation column.

[0018] Explanation of the reference numerals: 1-Upper frame, 2-Lower frame, 3-Isolation column, 4-Workpiece, 5-Cladle, 6-Snap fastener, 7-Base, 8-Handle, H-Height of interlayer space, T-Thickness of workpiece, d-Gap on one side. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0020] A batch clamping fixture for chemical plating based on structural constraints includes a clamping unit comprising an upper frame, a lower frame, and isolation columns connecting the upper and lower frames. After assembly via the isolation columns, the upper and lower frames have corresponding hollow structures, the contours of which match the planar projection contours of the workpiece. A sandwich structure exists between the upper and lower frames. Longitudinal and transverse protrusions are provided around the hollow structures to constrain the parts within the hollow structure area. The sandwich thickness H satisfies 1.05T < H ≤ 1.15T, where T is the thickness of the workpiece. Isolation column connection holes are provided on the upper and lower frames. The isolation columns are round rods that are pressed into the corresponding holes of the upper and lower frames via an interference fit. The upper and lower frames are respectively provided with locking blocks or sleeves for mutual connection and fixation.

[0021] The clamping unit comprises several sets, and adjacent clamping units are connected by clips or sleeves on the upper and lower frames. The isolation column has threads, and the interlayer thickness H is adjusted by adjusting the fixed position with nuts.

[0022] The clamping unit has a handle.

[0023] The clamping unit has a base underneath, and the base has several through holes. Example 1

[0024] The clamping unit of this invention consists of an upper frame 1, a lower frame 2, and eight isolation posts 3. The upper frame is a rectangular polypropylene frame, machined by CNC to ensure precision. The isolation posts 3 are fixed-length polytetrafluoroethylene round rods, pressed into the holes of the frame by interference fit. The workpiece 4 to be processed is an electronic component with a thickness T=2mm.

[0025] According to the present invention, the height of the interlayer space is designed to be 2.2 mm, satisfying H=1.1T. At this time, the single-sided gap d=0.1 mm. In actual operation, the worker gently places the workpiece 4 onto the lower frame 2, then covers it with the upper frame 1, and inserts the locking block 5 into the buckle 6 to fix the two layers, thus completing the entire fixture preparation. The workpiece can sway slightly within it, but any attempt to flip more than 0.2 mm will be immediately prevented.

[0026] like Figure 3 and Figure 4 As shown, five such clamping units are stacked together using sleeves 5 and clips 6, with a base 7 installed at the bottom and handles 8 on the sides, and then placed into a chemical nickel plating bath. The plating solution can freely penetrate each layer, ensuring uniform deposition on all workpieces. After removal from the bath, the fixture is disassembled, and the workpieces are taken out. All workpiece surfaces are intact, with uniform plating, and no flipping or missed plating occurs. Example 2

[0027] In another embodiment, to accommodate various parts with thicknesses of 2-2.5mm, the isolation post 3 is designed to be adjustable. Specifically, the isolation post 3 consists of two externally threaded metal rods and a nut, such as... Figure 8 As shown, the surface is coated with an anti-corrosion layer, and the effective length of the metal rod can be continuously adjusted to change the height H of the clamping space. For a workpiece with H=2mm, H is adjusted to 2.2mm; for a part with T=2.5mm, H is adjusted to 2.75mm.

[0028] This design greatly improves the versatility of the tooling without violating the core principles of the invention.

Claims

1. A batch clamping fixture for chemical plating based on structural positioning, characterized in that, It includes at least one clamping unit, which includes an upper frame, a lower frame, and a separation column connecting the upper and lower frames. After the upper and lower frames are assembled by the separation column, the upper and lower frames have corresponding hollow structures. The outline of the hollow structure matches the planar projection outline of the workpiece. There is a sandwich between the upper and lower frames. Longitudinal and transverse protrusions are provided around the hollow structure to constrain the part within the hollow structure area. The thickness H of the sandwich satisfies 1.05T<H≤1.15T, where T is the thickness of the part.

2. The chemical plating batch clamping fixture based on structural limiting according to claim 1, characterized in that, The upper and lower frames are provided with isolation column connection holes. The isolation column is a round rod that is pressed into the corresponding holes of the upper and lower frames by interference fit.

3. The chemical plating batch clamping fixture based on structural limiting according to claim 1, characterized in that, The upper and lower frames are respectively equipped with clips or sleeves, which are connected and fixed to each other.

4. The chemical plating batch clamping fixture based on structural limiting according to claim 1, characterized in that, The clamping unit consists of several groups, and adjacent clamping units are connected by clips or sleeves on the upper and lower frames.

5. The chemical plating batch clamping fixture based on structural limiting according to claim 1, characterized in that, The isolation column has threads, and the thickness H of the interlayer can be adjusted by adjusting the fixed position with a nut.

6. The chemical plating batch clamping fixture based on structural limiting according to claim 1, characterized in that, The clamping unit has a handle.

7. The chemical plating batch clamping fixture based on structural limiting according to claim 1, characterized in that, The clamping unit has a base underneath, and the base has several through holes.

8. A method for using a chemical plating batch clamping fixture based on structural positioning, characterized in that, Using any one of the toolings described in claims 1 to 7, the workpiece is placed into the interlayer space, and the workpiece floats and is fixed in the interlayer space under the impact of the plating solution due to the fit clearance between the interlayer space and the workpiece.

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