Method for integrating copper cutting chips

Abstract

To provide an integration method of copper cutting waste which can reduce operation energy and avoid deterioration of electric resistance value due to lowering of purity of copper.SOLUTION: An integration method of copper cutting waste comprises: a mounting step (S11) which scatters and mounts copper cutting waste 101 on a die with a recess part; and an integration step (S12) in which a rotatable and columnar rotary tool 103 is pressed against the copper cutting waste laid on the recess part of the die 102, the columnar rotary tool 103 is rotated so that the copper cutting waste is heated to be more than softening temperature of copper, and the copper cutting waste is agitated in the recess part of the die 102 by the columnar rotary tool 103 to integrate the copper cutting waste.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for integrating copper cutting chips.

Background Art

[0002] In the current motor manufacturing line, a considerable amount of copper cutting chips are generated when stripping the coil coating. These copper cutting chips are returned to copper products by melting and refining. Patent Document 1 describes a method of sinking and melting a briquette obtained by compressing and solidifying cutting chips of a copper alloy containing an alloy component having a melting point lower than that of copper into molten metal.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the melting and refining as in Patent Document 1 has problems such as requiring a large amount of operating energy and a large amount of carbon dioxide emissions, and oxygen being mixed during melting, resulting in a decrease in copper purity and a deterioration of the electrical resistance value.

[0005] In particular, the melting point of copper is 1100 °C. To reach the molten metal temperature of copper by melting and refining, the operating energy increases and copper is more likely to oxidize.

Means for Solving the Problems

[0006] One embodiment of the method for integrating copper cutting chips comprises a placement step of scattering and placing copper cutting chips on a die having a recess, and an integration step of pressing a rotatable cylindrical rotating tool against the copper cutting chips placed on the recess of the die and rotating the cylindrical rotating tool to heat the copper cutting chips to a temperature above the softening temperature of copper, and stirring the copper cutting chips within the recess of the die with the cylindrical rotating tool to integrate the copper cutting chips.

[0007] One embodiment of the method for integrating copper cutting chips may include a particle size adjustment step in which copper cutting chips are collected in a shredder and the collected copper cutting chips are shredded to adjust their particle size; a pre-compression step in which the particle size-adjusted copper cutting chips are transferred to a recess in a die and the copper cutting chips are compressed with a punch; an integration step in which the integration step is performed after the pre-compression step; and a removal step in which the integrated copper cutting chips are removed from the die after the integration step. [Effects of the Invention]

[0008] The method for integrating copper cutting chips described herein can reduce operating energy. Furthermore, it can avoid the deterioration of electrical resistance due to a decrease in copper purity. [Brief explanation of the drawing]

[0009] [Figure 1] This flowchart and schematic diagram show an example of a method for integrating copper cutting chips according to Embodiment 1. [Figure 2] This is a schematic diagram illustrating the method for integrating copper cutting chips according to Embodiment 1. [Figure 3] This is a bar graph showing a comparison of the energy used in the refining process. [Figure 4] This flowchart and schematic diagram show an example of a method for integrating copper cutting chips according to Embodiment 2. [Modes for carrying out the invention]

[0010] Embodiment 1 Embodiments of this disclosure will be described below with reference to the drawings. Figure 1 is a flowchart and schematic diagram showing an example of a copper cutting chip integration method according to Embodiment 1.

[0011] First, in step S11, copper cutting chips 101 are scattered and placed on the die having a recess. Then, the process proceeds to step S12.

[0012] Next, in step S12, a rotatable cylindrical rotary tool 103 is pressed against the copper cutting chips placed in the recess of the die 102, and the cylindrical rotary tool 103 is rotated. This rotation heats the copper cutting chips 101 to a temperature above the softening temperature of copper. Along with this heating, the copper cutting chips 101 are agitated by the cylindrical rotary tool 103 within the recess of the die 102, causing the copper cutting chips 101 to become a single, integrated mass. Then, the integrated copper cutting shavings 104 are removed from the die 102.

[0013] Next, friction stir welding will be explained. Figure 2 is a schematic diagram illustrating the method for integrating copper cutting chips according to Embodiment 1. As shown in Figure 2, friction stir welding (FSW) is a technique in which a rotating tool 201 is pressed against a workpiece 202, the frictional heat generated heats the workpiece to the copper softening temperature of 200-300°C, and the workpiece 202 is integrated by stirring with the tool 201.

[0014] Since heat generation occurs locally near tool 201, the energy required to raise the temperature of a 20mm x 20mm x 20mm area around workpiece 202 to 300°C was calculated using the specific heat of the material. Table 1 shows the weight, specific heat, and required energy for each component. [Table 1] This energy is equivalent to 0.12 kWh / kg per kilogram of copper.

[0015] Next, the energy required for FSW was estimated as follows. FIG. 3 is a bar graph showing a comparison of refining process energies. In FIG. 3, the vertical axis indicates the refining process energy, and the horizontal axis indicates the material type. As shown in FIG. 3, the energy of FSW is extremely smaller than the energy required for melting and refining.

[0016] Thus, according to the method for integrating copper cuttings according to Embodiment 1, by collecting the copper cuttings and applying FSW energy to solidify them integrally, the operating energy can be reduced. Further, according to the method for integrating copper cuttings according to Embodiment 1, the copper cuttings can be integrated without melting and refining, and deterioration of the electrical resistance value due to a decrease in copper purity can be avoided.

[0017] Embodiment 2 When copper cuttings are collected and a rotating tool is applied directly to them, the copper chips may scatter. In Embodiment 2, a method for integrating copper cuttings that can also handle the case where the copper chips scatter will be described. FIG. 4 is a flowchart and a schematic diagram showing an example of the method for integrating copper cuttings according to Embodiment 2.

[0018] First, in step S41, copper cuttings 401 are prepared. Then, the process proceeds to step S42.

[0019] Next, in step S42, the copper cuttings 401 are collected in the shredder 402. By applying the collected copper cuttings 401 to the shredder 402, the particle size of the copper cuttings is adjusted. Then, the process proceeds to step S43.

[0020] In step S43, the copper cuttings 401 with adjusted particle size are transferred to the recess of the die 403. Then, the copper cuttings 401 are compressed by the punch 404. The compression is desirably at a pressing force that does not impose a burden on the mold (generally, 700 MPa is a guide). Then, the process proceeds to step S44.

[0021] In step S44, a rotatable cylindrical rotary tool 405 is pressed against the copper cutting chips 401 placed in the recess of the die 403, and the cylindrical rotary tool 405 is rotated. This rotation heats the copper cutting chips 401 above the softening temperature of copper. Along with this heating, the copper cutting chips 401 are agitated by the cylindrical rotary tool 405 within the recess of the die 403, and the copper cutting chips 401 become a single unit. Then the process proceeds to step S45.

[0022] In step S45, the integrated copper cutting chip 406 is removed from the die.

[0023] As described above, according to the copper cutting chip integration method of Embodiment 2, by adjusting the particle size of the copper cutting chips, compressing the copper cutting chips, and then applying FSW energy to solidify them as a single unit, stable, integrated copper can be obtained without the copper chips scattering.

[0024] It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. For example, instead of using a shredder (crusher) to adjust the particle size, it may be crushed with rolling mill rolls. [Explanation of symbols]

[0025] 101, 104, 401, 406 Copper cutting waste 102, 403 Dies 103, 405 Cylindrical Rotation Tool 201 Tools 202 Work 402 Shredder 404 Punch

Claims

[Claim 1] A loading step in which copper cutting chips are scattered onto a die having a recess, A method for integrating copper cutting chips, comprising: an integration step of pressing a rotatable cylindrical rotating tool against the copper cutting chips placed in a recess of the die and rotating the cylindrical rotating tool to heat the copper cutting chips to a temperature above the softening temperature of copper, and stirring the copper cutting chips within the recess of the die with the cylindrical rotating tool to integrate the copper cutting chips, The system includes a particle size adjustment step in which the copper cutting chips are collected in a shredder, and the collected copper cutting chips are shredded to adjust their particle size, After the particle size adjustment step, the copper cutting chips with adjusted particle size are transferred to the recess of the die, and a pre-compression step is performed in which the copper cutting chips are compressed with a punch. After the pre-compression step, the integration step is performed. A method for integrating copper cutting chips, comprising a removal step of removing the integrated copper cutting chips from the die after the integration step.

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