A concave spinning process and spinning tool for precious metal materials

Abstract

The present invention relates to a process for preparing precious metal jewelry, and more specifically to a concave spinning process and a spinning tool for precious metal materials. The process of the present invention comprises the following steps: 1. preparing a copper blank according to the shape of the jewelry; 2. electroforming and depositing precious metal on the surface of the copper blank to form a precious metal jewelry shell on the surface of the copper blank; 3. etching away the copper blank inside the precious metal jewelry shell with nitric acid to obtain a hollow precious metal jewelry shell; and 4. fixing the precious metal jewelry shell obtained in step 3 to the fixture of a CNC machine, and controlling the spinning tool to rotate and press downward against the surface of the precious metal jewelry shell by the CNC machine to form a concave portion on the surface of the precious metal shell. The spinning tool of the present invention comprises a tool bar and a tool head disposed at the bottom of the tool bar. The tool head is flat and comprises a triangular spinning portion at the bottom and a rectangular shaping portion at the top. The process and tool of the present invention can spin a concave portion for placing diamonds on precious metal jewelry with a thickness of 0.2-0.3 mm.

Description

Technical Field

[0001] The invention relates to a process for preparing precious metal jewelry, and in particular to a concave spinning process for precious metal materials and a spinning tool. Background Art

[0002] Prior art requires CNC machining to create diamond-holding recesses and diamond-fixing nails in precious metal during the production process of some precious metal jewelry. However, CNC machining can only be used to create recesses in precious metal jewelry with a thickness of 1mm or more. To reduce production costs, the thickness and weight of precious metal jewelry must be kept to a minimum, with thicknesses below 1mm. Therefore, CNC machining cannot be used to create diamond-holding recesses in such precious metal jewelry. Summary of the Invention

[0003] In order to overcome the shortcomings of the existing technology, the first purpose of the present invention is to provide a concave spinning process for precious metal materials, which can spin out a concave position that is more than 3 times thicker than the metal layer based on the thickness of the electroformed metal layer without destroying the structural strength of the jewelry.

[0004] A second object of the present invention is to provide a spinning tool that can spin out a recess for placing a diamond on precious metal jewelry with a thickness of 0.2-0.3 mm.

[0005] The first object of the present invention is achieved through the following technical solutions:

[0006] A concave spinning process for precious metal materials, comprising the following steps:

[0007] Step 1: Make a copper blank according to the shape of the jewelry;

[0008] Step 2: Electroforming and depositing precious metal on the surface of the copper blank to form a precious metal jewelry shell on the surface of the copper blank;

[0009] Step 3: Use nitric acid to corrode the copper blank inside the precious metal jewelry shell to obtain a hollow precious metal jewelry shell;

[0010] Step 4: Fix the precious metal jewelry shell obtained in step 3 to the fixture of the CNC machine, install the spinning tool on the CNC machine, and control the spinning tool to rotate and press downward on the surface of the precious metal jewelry shell through the CNC machine to form a concave position on the surface of the precious metal shell.

[0011] The specific steps of depositing the precious metal in step 2 are as follows:

[0012] S1. Degrease and wax the surface of the copper embryo and clean it;

[0013] S2, fixing the cleaned copper blank on the electroforming hanger;

[0014] S3. Place the hanger into the electroforming tank containing the gold solution for electroforming. Control the water temperature to 55-65°C, the current to 0.5-1.5A, and the voltage to 1.0-2.0V.

[0015] Among them, in the step three, when using nitric acid to corrode the copper embryo, first drill at least two through holes connecting to the interior of the precious metal jewelry shell on the precious metal jewelry shell, then place the precious metal jewelry shell with the copper embryo inside into a nitric acid solution, and heat the nitric acid solution until the nitric acid solution boils.

[0016] Wherein, the diameter of the through hole is 0.5 mm.

[0017] Wherein, the concentration of the nitric acid solution is 95%.

[0018] Wherein, in the step 4, the rotation speed of the spinning tool is 11500 rpm-12500 rpm, and the downward pressure of the spinning tool is 0.44-0.54 mbar.

[0019] The process of the present invention can spin out recesses that are more than three times thicker than the thickness of the electroformed metal layer on the basis of the thickness of the metal layer, without damaging the structural strength of the jewelry. It reserves a precise reference surface for CNC processing and enables the placement of diamonds larger than 1 mm in metal thickness below 1 mm, making the setting more secure and more beautiful, and the jewelry lighter and more affordable.

[0020] The second object of the present invention is achieved through the following technical solutions:

[0021] A spinning tool comprises a tool rod and a tool head arranged at the bottom of the tool rod, the tool head is flat, and comprises a spinning part with a triangular lower part and a rectangular upper part, the tip of the spinning part faces downward, the upper and lower ends of the forming part are respectively connected to the tool rod and the upper end of the spinning part, the two opposite side surfaces in the width direction of the tool head are spinning friction surfaces, the side edges of the tool head are each provided with an arc-shaped first guide surface, the first guide surface extends from the spinning friction surface to the side surface located in the thickness direction of the tool head, and arc-shaped second guide surfaces are provided on both sides of the tool head in the width direction and at the intersection of the spinning part and the forming part, and the tip of the spinning part is provided with an arc-shaped spinning surface.

[0022] Wherein, the angle formed by the two side edges of the bottom of the spinning part is 70-75°.

[0023] Wherein, the diameter of the spinning surface is 0.05-0.15 mm.

[0024] Wherein, the thickness of the cutter head is 0.35-0.45 mm.

[0025] The beneficial effects of the present invention are:

[0026] The process of the present invention can spin out recesses that are more than three times thicker than the thickness of the electroformed metal layer on the basis of the thickness of the metal layer, without damaging the structural strength of the jewelry. It reserves a precise reference surface for CNC processing and enables the placement of diamonds larger than 1 mm in metal thickness below 1 mm, making the setting more secure and more beautiful, and the jewelry lighter and more affordable.

[0027] When the cutting tool of the present invention is used, a CNC machine tool is used to control the cutting tool to rotate and press downward against the precious metal material. The rotating and pressing action of the cutting tool's spinning portion causes the surface of the precious metal material to be depressed downward to form a recess for placing diamonds. By providing an arc-shaped spinning surface at the tip of the spinning portion, it is ensured that when the cutting tool spins the precious metal downward, a recess is pressed into the precious metal surface, and that the lower end of the spinning portion does not press a hole through the precious metal material. The provision of the first guide surface and the second guide surface prevents the cutting tool edge from cutting the precious metal during the spinning process, causing perforation of the precious metal material, or the recess after spinning not meeting production requirements. Using this cutting tool, a recess for placing diamonds with a thickness of more than 1 mm can be spun into the surface of a metal material with a thickness of 0.2-0.3 mm. The depth of the spun recess is more than three times the thickness of the metal material, facilitating the production of lighter, thinner, and more affordable precious metal jewelry. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be further described below with reference to the accompanying drawings and examples.

[0029] Figure 1 is a schematic diagram of the overall structure of Example 4 of the present invention;

[0030] Figure 2 is a side view of a cutter head according to embodiment 4 of the present invention;

[0031] Figure 3 This is another side view of the cutter head according to embodiment 4 of the present invention.

[0032] Explanation of the accompanying reference numerals: 1. tool rod; 2. tool head; 3. spinning portion; 4. shaping portion; 5. spinning friction surface; 6. first guide surface; 7. second guide surface; 8. spinning surface; 9. first connecting section; 10. second connecting section; 11. buffer section; 12. yield surface. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the concept, specific structure and technical effects of the present invention in combination with the embodiments and drawings, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention. In addition, all the connection / connection relationships involved in the patent do not refer to the direct connection of components, but refer to the fact that a better connection structure can be formed by adding or reducing connection accessories according to the specific implementation situation. The various technical features in the invention can be combined interactively without conflicting with each other.

[0034] Example 1

[0035] A concave spinning process for precious metal materials, comprising the following steps:

[0036] Step 1: Use CNC lathe to process the copper workpiece into the required copper blank according to the shape of the jewelry;

[0037] Step 2: Electroforming and depositing precious metal on the surface of the copper blank to form a precious metal jewelry shell on the surface of the copper blank;

[0038] Step 3: Use nitric acid to corrode the copper blank inside the precious metal jewelry shell to obtain a hollow precious metal jewelry shell;

[0039] Step 4: Fix the precious metal jewelry shell obtained in step 3 to the fixture of the CNC machine, install the spinning tool on the CNC machine, and control the spinning tool to rotate and press downward on the surface of the precious metal jewelry shell through the CNC machine to form a concave position on the surface of the precious metal shell.

[0040] The specific steps of depositing the precious metal in step 2 are as follows:

[0041] S1. Degrease and wax the surface of the copper embryo and clean it;

[0042] S2, fixing the cleaned copper blank on the electroforming hanger;

[0043] S3. Place the hanger into the electroforming tank containing the gold solution for electroforming. Control the water temperature to 60°C, the current to 1A, and the voltage to 1.5V.

[0044] Among them, in the step three, when using nitric acid to corrode the copper embryo, first drill two through holes connecting to the interior of the precious metal jewelry shell at both ends in the longest direction, then place the precious metal jewelry shell with the copper embryo inside into a nitric acid solution, and heat the nitric acid solution until the nitric acid solution boils.

[0045] Wherein, the diameter of the through hole is 0.5 mm.

[0046] Wherein, the concentration of the nitric acid solution is 95%.

[0047] Wherein, in the step 4, the rotation speed of the spinning tool is 12000 rpm, and the downward pressure of the spinning tool is 0.49 mbar.

[0048] The Vickers hardness of the precious metal jewelry shell is 100, and the thickness of the precious metal jewelry shell is 0.25 mm.

[0049] Example 2

[0050] A concave spinning process for precious metal materials, comprising the following steps:

[0051] Step 1: Use CNC lathe to process the copper workpiece into the required copper blank according to the shape of the jewelry;

[0052] Step 2: Electroforming and depositing precious metal on the surface of the copper blank to form a precious metal jewelry shell on the surface of the copper blank;

[0053] Step 3: Use nitric acid to corrode the copper blank inside the precious metal jewelry shell to obtain a hollow precious metal jewelry shell;

[0054] Step 4: Fix the precious metal jewelry shell obtained in step 3 to the fixture of the CNC machine, install the spinning tool on the CNC machine, and control the spinning tool to rotate and press downward on the surface of the precious metal jewelry shell through the CNC machine to form a concave position on the surface of the precious metal shell.

[0055] The specific steps of depositing the precious metal in step 2 are as follows:

[0056] S1. Degrease and wax the surface of the copper embryo and clean it;

[0057] S2, fixing the cleaned copper blank on the electroforming hanger;

[0058] S3. Place the hanger into the electroforming tank containing the gold solution for electroforming. Control the water temperature to 55°C, the current to 0.5A, and the voltage to 1.0V.

[0059] Among them, in the step three, when using nitric acid to corrode the copper embryo, first drill two through holes connecting to the interior of the precious metal jewelry shell at both ends in the longest direction, then place the precious metal jewelry shell with the copper embryo inside into a nitric acid solution, and heat the nitric acid solution until the nitric acid solution boils.

[0060] Wherein, the diameter of the through hole is 0.5 mm.

[0061] Wherein, the concentration of the nitric acid solution is 95%.

[0062] Wherein, in the step 4, the rotation speed of the spinning tool is 11500 rpm, and the downward pressure of the spinning tool is 0.44 mbar.

[0063] The Vickers hardness of the precious metal jewelry shell is 90, and the thickness of the precious metal jewelry shell is 0.2 mm.

[0064] Example 3

[0065] A concave spinning process for precious metal materials, comprising the following steps:

[0066] Step 1: Use CNC lathe to process the copper workpiece into the required copper blank according to the shape of the jewelry;

[0067] Step 2: Electroforming and depositing precious metal on the surface of the copper blank to form a precious metal jewelry shell on the surface of the copper blank;

[0068] Step 3: Use nitric acid to corrode the copper blank inside the precious metal jewelry shell to obtain a hollow precious metal jewelry shell;

[0069] Step 4: Fix the precious metal jewelry shell obtained in step 3 to the fixture of the CNC machine, install the spinning tool on the CNC machine, and control the spinning tool to rotate and press downward on the surface of the precious metal jewelry shell through the CNC machine to form a concave position on the surface of the precious metal shell.

[0070] The specific steps of depositing the precious metal in step 2 are as follows:

[0071] S1. Degrease and wax the surface of the copper embryo and clean it;

[0072] S2, fixing the cleaned copper blank on the electroforming hanger;

[0073] S3. Place the hanger into the electroforming tank containing the gold solution for electroforming. Control the water temperature to 65°C, the current to 1.5A, and the voltage to 2.0V.

[0074] Among them, in the step three, when using nitric acid to corrode the copper embryo, first drill two through holes connecting to the interior of the precious metal jewelry shell at both ends in the longest direction, then place the precious metal jewelry shell with the copper embryo inside into a nitric acid solution, and heat the nitric acid solution until the nitric acid solution boils.

[0075] Wherein, the diameter of the through hole is 0.5 mm.

[0076] Wherein, the concentration of the nitric acid solution is 95%.

[0077] Wherein, in the step 4, the rotation speed of the spinning tool is 12500 rpm, and the downward pressure of the spinning tool is 0.54 mbar.

[0078] The Vickers hardness of the precious metal jewelry shell is 110, and the thickness of the precious metal jewelry shell is 0.3 mm.

[0079] Example 4

[0080] Spinning tools used in the above process, such as Figure 1-3 As shown, it includes a tool rod 1 and a tool head 2 provided at the bottom of the tool rod 1. The tool head 2 is flat and includes a triangular spinning portion 3 at the bottom and a rectangular shaping portion 4 at the top. The tip of the spinning portion 3 faces downward, and the upper and lower ends of the shaping portion 4 are respectively connected to the tool rod 1 and the upper end of the spinning portion 3. The two opposite side surfaces in the width direction of the tool head 2 are spinning friction surfaces 5. The side edges of the tool head 2 are each provided with an arc-shaped first guide surface 6, which extends from the spinning friction surface 5 to the side surface in the thickness direction of the tool head 2. Arc-shaped second guide surfaces 7 are provided on both sides of the tool head 2 in the width direction and at the intersection of the spinning portion 3 and the shaping portion 4. The tip of the spinning portion 3 is provided with an arc-shaped spinning surface 8. Specifically, the spinning tool is made of tungsten steel alloy material.

[0081] The present invention sets the tool into the above-mentioned structure. When in use, the CNC machine tool is used to control the tool to rotate and press downward against the precious metal material. The rotation and downward pressing action of the tool spinning part 3 causes the surface of the precious metal material to be depressed downward to form a recess for placing diamonds. By providing an arc-shaped spinning surface 8 at the tip of the spinning part 3, it is ensured that when the tool spins the precious metal downward, a recess is pressed on the precious metal surface, and it is also ensured that the lower end of the spinning part 3 does not press a hole through the precious metal material. The provision of the first guide surface 6 and the second guide surface 7 can prevent the tool edge from cutting the precious metal during the spinning process, causing perforation of the precious metal material, or the recess after spinning does not meet production requirements. Using this tool, a recess for placing diamonds with a thickness of more than 1 mm can be spun on the surface of a metal material with a thickness of 0.2-0.3 mm. The depth of the spun recess is more than three times the thickness of the metal material, which facilitates the production of lighter, thinner, and more affordable precious metal jewelry.

[0082] Among them, in order to enable the tool to spin out a recess that is more suitable for placing diamonds with a thickness of more than 1 mm, the thickness of the tool head 2 is 0.35-0.45 mm. The setting of this thickness can further avoid the tool from cutting the metal material during the spinning process, ensuring that the tool can stably spin out the recess.

[0083] In order to make the diamond more firmly embedded in the concave position spun by the tool, the angle formed by the two sides of the bottom of the spun part 3 is 70-75 degrees.

[0084] In order to further ensure that the tool can smoothly spin out a recess on the surface of the metal material without causing cutting action on the metal material, the diameter of the spinning surface 8 is 0.05-0.15 mm.

[0085] The shank 1 includes a first connecting section 9 and a second connecting section 10 . The first connecting section 9 and the second connecting section 10 are both cylindrical. The diameter of the first connecting section 9 is greater than the diameter of the second connecting section 10 .

[0086] The cylindrical first connecting section 9 and the second connecting section 10 are conducive to better rotation of the tool and reduce the collision between the tool and other surrounding objects or structures during rotation. The diameter of the second connecting section 10 is set to be smaller than the diameter of the first connecting section 9. On the one hand, the diameter of the first connecting section 9 is larger, and its strength is correspondingly larger, which is conducive to improving the strength of the tool. On the other hand, the second connecting section 10 is close to the cutter head 2, and the diameter of the second connecting section 10 is smaller, and its volume is smaller, which can avoid the tool from colliding with the metal jewelry when the second connecting section 10 is close to the metal jewelry when processing the metal jewelry, which is more conducive to the tool to better process the metal jewelry.

[0087] In order to further improve the overall strength of the tool, a truncated cone-shaped buffer section 11 is provided between the first connecting section 9 and the second connecting section 10. The upper end diameter of the buffer section 11 is equal to the diameter of the first connecting section 9, and the lower end diameter of the buffer section 11 is equal to the diameter of the second connecting section 10.

[0088] To further prevent the tool bar 1 from colliding with precious metals when the tool is processing metal materials, two inclined clearance surfaces 12 are provided at the lower end of the first connecting section 9. The two clearance surfaces 12 are located on both sides of the thickness direction of the tool head 2. The bottoms of the two clearance surfaces 12 are respectively connected to the two side surfaces of the tool head 2 in the thickness direction. The clearance surfaces 12 gradually tilt from the direction close to the axis of the first connecting section 9 to the direction away from the axis of the first connecting section 9 from bottom to top. The provision of the clearance surfaces 12 is more conducive to the tool processing of precious metal jewelry, improving processing efficiency.

[0089] The first connecting section 9 , the buffer section 11 , the second connecting section 10 and the cutter head 2 are coaxially arranged.

[0090] The spinning tool is integrally formed, and the integrally formed tool has higher overall strength, is less likely to deform, and is more conducive to extending its service life.

[0091] Wherein, the surface roughness of the spinning tool is Ra0.004-Ra0.006.

[0092] The above is a specific description of the preferred implementation of the present invention, but the invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A concave spinning process for precious metal materials, characterized by: The steps include: Step 1: Make a copper blank according to the shape of the jewelry; Step 2: Electroforming and depositing precious metal on the surface of the copper blank to form a precious metal jewelry shell on the surface of the copper blank; Step 3: Use nitric acid to corrode the copper blank inside the precious metal jewelry shell to obtain a hollow precious metal jewelry shell; Step 4: Fix the precious metal jewelry shell obtained in Step 3 to the fixture of the CNC machine, install the spinning tool on the CNC machine, and control the spinning tool to rotate and press downward on the surface of the precious metal jewelry shell through the CNC machine to form a concave portion on the surface of the precious metal shell; The spinning tool includes a tool rod and a tool head arranged at the bottom of the tool rod, the tool head is flat, and includes a spinning part with a triangular lower part and a forming part with a rectangular upper part, the tip of the spinning part faces downward, the upper and lower ends of the forming part are respectively connected to the tool rod and the upper end of the spinning part, the two opposite side surfaces in the width direction of the tool head are spinning friction surfaces, the side edges of the tool head are each provided with an arc-shaped first guide surface, the first guide surface extends from the spinning friction surface to the side surface located in the thickness direction of the tool head, and arc-shaped second guide surfaces are provided on both sides of the width direction of the tool head and at the intersection of the spinning part and the forming part, and the tip of the spinning part is provided with an arc-shaped spinning surface.

2. A concave spinning process for precious metal materials according to claim 1, characterized in that: The specific steps of depositing the precious metal in step 2 are as follows: S1. Degrease and wax the surface of the copper embryo and clean it; S2, fixing the cleaned copper blank on the electroforming hanger; S3. Place the hanger into the electroforming tank containing the gold solution for electroforming. Control the water temperature to 55-65°C, the current to 0.5-1.5A, and the voltage to 1.0-2.0V.

3. A concave spinning process for precious metal materials according to claim 1, characterized in that: In step 3, when using nitric acid to corrode the copper blank, at least two through holes that communicate with the interior of the precious metal jewelry shell are first drilled on the precious metal jewelry shell, and then the precious metal jewelry shell with the copper blank inside is placed in a nitric acid solution, and the nitric acid solution is heated until the nitric acid solution boils.

4. A concave spinning process for precious metal materials according to claim 3, characterized in that: The diameter of the through hole is 0.5 mm.

5. The concave spinning process for precious metal materials according to claim 3, characterized in that: The concentration of the nitric acid solution is 95%.

6. The spinning tool according to claim 1, characterized in that: The angle formed by the two side edges of the bottom of the spinning portion is 70-75°.

7. The spinning tool according to claim 1, characterized in that: The diameter of the spinning surface is 0.05-0.15 mm.

8. The spinning tool according to claim 1, characterized in that: The thickness of the cutter head is 0.35-0.45 mm.

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