Production process of a stepped copper strip

Abstract

The present invention relates to a production process of a stepped copper strip. A copper rod enters an extrusion forming die of a continuous extruder for extrusion. The softened copper rod enters the die after passing through a gasket for flow splitting, and then forms a stepped copper strip through respective shaping by a segmented sizing belt. A leading strip is added to the thin edge of the preliminarily formed stepped copper strip, and the leading strip and the stepped copper strip are drawn synchronously. After the leading strip and the stepped copper strip come out of the drawing machine, they are respectively wound up. In the extrusion process of the present invention, the pressure is small, and copper bars with different thicknesses are produced through continuous extrusion, greatly simplifying the production process flow of special-shaped copper strip products.

Description

Technical Field

[0001] The present invention relates to the technical field of non-ferrous metal processing, and particularly relates to a production process of stepped copper strips. Background Art

[0002] Stepped copper strips are mainly used in high and low voltage switches, lead frames of plastic encapsulated semiconductor components, and flexible connection conductors of new energy vehicles, etc. At present, most of the stepped copper strips on the market adopt a multi-pass rolling process or a process of flattening by stamping. The former process is complex and requires multiple heat treatments, and special-shaped rolling rolls for multiple passes need to be manufactured, with an extremely long production cycle; while the latter stamping and flattening process will cause inconsistent overall hardness uniformity of the material, affecting the final product use effect, with a low finished product qualification rate and high production cost. Summary of the Invention

[0003] The purpose of the present invention is to overcome the above deficiencies, and provides a production process of stepped copper strips. By continuous extrusion to form a special-shaped copper bar with different thicknesses, it can improve the production efficiency of special-shaped copper strips, reduce production costs at the same time, and ensure the stability of the mechanical properties of the product; the pressure during the extrusion process is small, and copper bars with different thicknesses can be produced through such an extrusion method, greatly simplifying the production process flow of special-shaped copper strip products, and also ensuring the overall uniformity of the material and the consistency of mechanical properties during the subsequent cold deformation process.

[0004] The purpose of the present invention is achieved as follows:

[0005] A production process of stepped copper strips, comprising the following steps:

[0006] Step 1, extrusion: The copper rod enters the extrusion forming die of the continuous extruder for extrusion. The softened copper rod enters the die through the gasket shunt and then enters the die, and is formed into a stepped copper strip through the segmented sizing belt respectively.

[0007] Step 2, cold drawing: The lead tape is added to the thin edge of the preliminarily formed stepped copper strip, and the lead tape and the stepped copper strip are drawn synchronously. After the lead tape and the stepped copper strip come out of the drawing machine, they are wound up respectively.

[0008] Preferably, the extrusion forming die includes a die cavity, a gasket and a die. An inlet cavity and a die accommodation cavity are provided in the die cavity. A gasket and a die are provided in the die accommodation cavity, and the die is arranged outside the gasket.

[0009] Preferably, an inlet channel, a first sizing belt and a second sizing belt are provided in the die. The first sizing belt and the second sizing belt are arranged on the outlet side of the die, and the inlet channel is arranged on the inlet side of the die.

[0010] Preferably, the first sizing belt and the second sizing belt are arranged left and right, and the connection part is communicated.

[0011] Preferably, the first sizing belt and the second sizing belt are respectively communicated with the feeding channel.

[0012] Preferably, the thickness of the first sizing belt is less than that of the second sizing belt, and the length of the first sizing belt is less than that of the second sizing belt.

[0013] Preferably, the gasket is provided with a shunt hole, the shunt hole is in an "8" shape, and the middle of the shunt hole is thin and the two sides are thick.

[0014] Preferably, the mold base material is hot work die steel, an alloy die core is embedded on the outlet side of the hot work die steel, and the first sizing belt and the second sizing belt are arranged on the alloy die core.

[0015] Preferably, an alloy dovetail is further arranged between the hot work die steel and the alloy die core.

[0016] The beneficial effects of the present invention are as follows:

[0017] 1. The gasket adopts an "8"-shaped shunt hole to ensure that the metal fills the edges of each sizing belt, facilitating the forming of the stepped copper strip;

[0018] 2. The mold adopts a segmented sizing design. The length of the first sizing belt is less than that of the second sizing belt, reducing the resistance of the metal entering the first sizing belt and increasing the resistance of the metal entering the second sizing belt, balancing the flow rate of the metal entering the first sizing belt and the second sizing belt, and facilitating the overall forming of the stepped copper strip;

[0019] 3. The leading strip adopts a profile with a thickness difference equal to that of the special-shaped copper strip material. The leading strip is increased to the thin edge and rotates together with the stepped copper strip during the drawing process, so that there is also a supporting stress point for the thin edge of the stepped copper strip, ensuring the straightness and flatness of the material during the drawing process and greatly improving the product quality.

[0020] 4. The mold cavity adopts a flat feeding cavity, reducing the pressure of the material during the extrusion process, facilitating the forming of the material, and at the same time improving the service life of the mold cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic structural diagram of the present invention.

[0022] Figure 2 is a schematic structural diagram of the extrusion forming mold.

[0023] Figure 3 is an assembly schematic diagram of the extrusion forming mold.

[0024] Figure 4 is the front view of the mold.

[0025] Figure 5 is Figure 4 the A-A sectional view of

[0026] Figure 6 is Figure 4 the B-B sectional view of

[0027] Figure 7 is Figure 4 the C-C sectional view of

[0028] Figure 8 is the schematic diagram of the positional relationship between the guiding strip and the stepped copper strip blank.

[0029] Wherein: the extrusion forming die 1; the die cavity 1.1; the feeding cavity 1.1.1; the die accommodating cavity 1.1.2; the gasket 1.2; the shunt hole 1.2.1; the die 1.3; the feeding channel 1.3.1; the first sizing belt 1.3.2; the second sizing belt 1.3.3; the hot work die steel 1.3.4; the alloy die core 1.3.5; the alloy dovetail 1.3.6; the drawing machine 2; the guiding strip 3; the stepped copper strip blank 4. Specific embodiments

[0030] Refer to Figures 1-8 , the present invention relates to a production device for stepped copper strips, including a continuous extrusion machine, a drawing machine 2 and a guiding strip 3. The continuous extrusion machine includes an extrusion forming die 1. The guiding strip 3 is wound and unwound by a guiding strip pay-off stand and a guiding strip take-up stand. The copper rod enters the extrusion forming die 1 of the continuous extrusion machine for extrusion to form a stepped copper strip blank 4. The stepped copper strip blank 4 and the guiding strip 3 enter the drawing machine 2 together for the drawing process.

[0031] The extrusion forming die 1 includes a die cavity 1.1, a gasket 1.2 and a die 1.3. The die cavity 1.1 is provided with a feeding cavity 1.1.1 and a die accommodating cavity 1.1.2. The feeding cavity 1.1.1 is flat. The die accommodating cavity 1.1.2 is provided with a gasket 1.2 and a die 1.3. The die 1.3 is arranged outside the gasket 1.2. The die 1.3 is provided with a feeding channel 1.3.1, a first sizing belt 1.3.2 and a second sizing belt 1.3.3. The first sizing belt 1.3.2 and the second sizing belt 1.3.3 are arranged on the outlet side of the die 1.3, and the first sizing belt 1.3.2 and the second sizing belt 1.3.3 are arranged left and right, and the connection part is communicated. The feeding channel 1.3.1 is arranged on the inlet side of the die 1.3.

[0032] The first sizing belt 1.3.2 and the second sizing belt 1.3.3 are respectively communicated with the feeding channel 1.3.1.

[0033] The bottom surfaces of the first sizing belt 1.3.2 and the second sizing belt 1.3.3 are flush. The first sizing belt 1.3.2 is used for forming the thin edge of the stepped copper strip, and the second sizing belt 1.3.3 is used for forming the thick edge of the stepped copper strip. The thickness of the first sizing belt 1.3.2 is less than that of the second sizing belt 1.3.3.

[0034] In order to balance the flow rates of the metal entering the first sizing belt 1.3.2 and the second sizing belt 1.3.3, the length of the first sizing belt 1.3.2 is less than that of the second sizing belt 1.3.3, reducing the resistance of the metal entering the first sizing belt 1.3.2 and increasing the resistance of the metal entering the second sizing belt 1.3.3, facilitating the overall forming effect of the stepped copper strip.

[0035] The gasket 1.2 is provided with a flow splitting hole 1.2.1. The flow splitting hole 1.2.1 is in an "8" shape, with the middle being thin and the two sides being thick, ensuring that the metal fills the first sizing belt 1.3.2 and the second sizing belt 1.3.3. The metal preferentially enters the edges of the first sizing belt 1.3.2 and the second sizing belt 1.3.3 from both sides of the flow splitting hole 1.2.1, ensuring that the edges of each sizing belt are filled with metal, facilitating the forming of the stepped copper strip.

[0036] The base material of the die 1.3 is hot work die steel 1.3.4. An alloy die core 1.3.5 is embedded on the outlet side of the hot work die steel 1.3.4. The first sizing belt 1.3.2 and the second sizing belt 1.3.3 are arranged on the alloy die core 1.3.5, shortening the extrusion channel and reducing the required extrusion pressure, greatly improving the strength of the die and reducing the material cost at the same time. The length of the second sizing belt 1.3.3 is consistent with the thickness of the alloy die core.

[0037] An alloy dovetail 1.3.6 is further provided between the hot work die steel 1.3.4 and the alloy die core 1.3.5, ensuring that the die does not deform severely.

[0038] A production process for a stepped copper strip includes the following steps:

[0039] Step 1, extrusion: The copper rod enters the extrusion forming die 1 of the continuous extruder for extrusion. The softened copper rod enters the gasket 1.2 from the die cavity 1.1 and is split and then enters the die 1.3, and is formed into a stepped copper strip 4 through the segmented sizing belts respectively;

[0040] Step 2, cold drawing: The leading strip 3 is added to the thin edge of the preliminarily formed stepped copper strip 4. The leading strip 3 and the stepped copper strip 4 are drawn synchronously. After the leading strip 3 and the stepped copper strip 4 come out of the drawing machine 2, they are wound up respectively.

[0041] Since the stepped copper strip is thin on one side and thick on the other side, during the drawing and coiling process, the contact surface under stress is only the side with the material thickness. This will cause serious straightness problems after the material is drawn. Therefore, a guide strip is designed in this process. The guide strip uses a profile with a thickness equal to the difference in thickness between the special-shaped copper strip materials. The guide strip is added to the thin side and rotates together with the stepped copper strip during the drawing process. As a result, there is also a supporting stress point on the thin side of the stepped copper strip, ensuring the straightness and flatness of the material during the drawing process and greatly improving the product quality.

[0042] The extrusion parameters of the continuous extruder are an extrusion speed of 9 revolutions per minute and an extrusion current of 420 - 440 A.

[0043] In addition to the above embodiments, the present invention also includes other implementation manners. Any technical solutions formed by equivalent transformation or equivalent substitution shall fall within the protection scope of the claims of the present invention.

Claims

1. A production process of a stepped copper strip, characterized in that: It includes the following steps: Step 1, extrusion: The copper rod enters the extrusion die of the continuous extruder for extrusion. The softened copper rod enters the die after passing through the gasket for flow splitting and then enters the die, and is formed into a stepped copper strip through the segmented sizing belts respectively. Step 2, cold drawing: The lead strip is added to the thin edge of the preliminarily formed stepped copper strip, and the lead strip and the stepped copper strip are drawn synchronously. After the lead strip and the stepped copper strip come out of the drawing machine, they are wound up respectively. The die is provided with a feed channel, a first sizing belt and a second sizing belt. The first sizing belt and the second sizing belt are arranged on the outlet side of the die, and the feed channel is arranged on the inlet side of the die. The thickness of the first sizing belt is less than that of the second sizing belt, the length of the first sizing belt is less than that of the second sizing belt, and the first sizing belt and the second sizing belt are arranged left and right, and the connection part is communicated. The lead strip adopts a profile with a thickness difference equal to that of the special-shaped copper strip material. The lead strip is added to the thin edge and drives together with the stepped copper strip during the drawing process, so that there is also a supporting stress point on the thin edge of the stepped copper strip, ensuring the straightness and flatness of the material during the drawing process.

2. The production process of a stepped copper strip according to claim 1, characterized in that: The extrusion die includes a die cavity, a gasket and a die. The die cavity is provided with a feed cavity and a die accommodation cavity. The die accommodation cavity is provided with a gasket and a die, and the die is arranged outside the gasket.

3. The production process of a stepped copper strip according to claim 1, characterized in that: The first sizing belt and the second sizing belt are respectively communicated with the feed channel.

4. The production process of a stepped copper strip according to claim 2, characterized in that: The gasket is provided with a flow splitting hole, the flow splitting hole is in an "8" shape, and the middle of the flow splitting hole is thin and the two sides are thick.

5. The production process of a stepped copper strip according to claim 1, characterized in that: The die base material is hot work die steel, and an alloy die core is embedded on the outlet side of the hot work die steel. The first sizing belt and the second sizing belt are arranged on the alloy die core.

6. The production process of a stepped copper strip according to claim 5, characterized in that: An alloy dovetail is further arranged between the hot work die steel and the alloy die core.

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