A method and apparatus for forming low residual stress components by variable-direction loading

Abstract

This invention belongs to the technical field of low residual stress component forming, and discloses a method and apparatus for forming low residual stress components by variable loading. The apparatus includes a punch, a die, and a side die assembly. The side die assembly is disposed in the die, which has a main cavity and a flow-dividing cavity that are interconnected. The flow-dividing cavity penetrates the side wall of the main cavity. The punch is detachably connected to the main cavity and is used to extrude the blank into the main cavity and the flow-dividing cavity to complete the preforming of the blank. The side die assembly deforms to cause the material at the corner of the preform to flow in a different direction, that is, to push the blank in the flow-dividing cavity into the main cavity. This invention enables the material at the corner of the low residual stress component to flow in a different direction, which greatly improves the material filling ability, reduces the residual stress at this location, improves the overall performance of the formed part, and greatly reduces the cost.

Description

Technical Field

[0001] This invention belongs to the technical field of low residual stress forming, and more specifically, relates to a method and apparatus for forming low residual stress components by variable loading. Background Technology

[0002] Residual stress has always been a concern during the forming process of metal parts. Currently, various methods are used to reduce residual stress in components, such as applying ultrasonic energy fields and liquid nitrogen fields to assist forming during the forming process; or performing post-processing on the formed samples, such as stress-relief annealing, tempering, and mechanical treatment.

[0003] However, applying an external energy field during the forming process not only increases energy consumption but also makes the manufacturing of the required equipment more complex and cost-effective. While post-processing methods reduce the difficulty of equipment manufacturing to some extent, they increase working hours and also consume a significant amount of energy. Summary of the Invention

[0004] In view of the above-mentioned defects or improvement needs of the prior art, the present invention provides a method and apparatus for forming low residual stress components by variable loading. The apparatus enables the material at the corner of the low residual stress component to flow in a different direction, which greatly improves the filling performance of the material and reduces the residual stress at that part, thereby improving the overall performance of the formed part and greatly reducing the cost.

[0005] To achieve the above objectives, according to one aspect of the present invention, an apparatus for forming a low residual stress component by directional loading is provided. The apparatus includes a punch, a die, and a side die assembly. The side die assembly is connected to the die. The die has a main cavity and a branch cavity that communicate with each other. The branch cavity penetrates the side wall of the main cavity. The punch is detachably connected to the main cavity and is used to extrude a blank into the main cavity and the branch cavity to complete the pre-forming of the blank.

[0006] The lateral mold assembly deforms to redirect the material flow at the corner of the preform, thereby pushing the blank in the split cavity into the main cavity.

[0007] Furthermore, the device also includes a temperature controller connected to the side mold assembly, which controls the local temperature of the side mold assembly, thereby controlling the amount of deformation so that the blank in the split mold cavity is just completely extruded into the main mold cavity.

[0008] Furthermore, the die also has a lateral cavity, which is connected to the flow-dividing cavity, and the flow-dividing cavity is located between the lateral cavity and the main cavity; the lateral cavity is used to accommodate the lateral die assembly.

[0009] Furthermore, the lateral module assembly includes a temperature sensor, a displacement sensor, a resistance wire, a stop block, and a connecting rod. The temperature sensor, the displacement sensor, and the resistance wire are respectively connected to the temperature controller. The displacement sensor is disposed on the inner wall of the lateral cavity. One end of the connecting rod extends into the lateral cavity and is connected to the stop block. A shape memory alloy is disposed on the connecting rod, and the shape memory alloy forms a cylindrical body. The temperature sensor and the resistance wire are disposed on the shape memory alloy.

[0010] Furthermore, the temperature sensor and the displacement sensor are used to detect the temperature of the shape memory alloy and the position of the stop block, respectively, and transmit the detected temperature data and position data to the temperature controller; the temperature controller is used to adjust the current in the resistance wire in real time according to the received temperature data and position data, so as to control the deformation of the shape memory alloy and realize the control of the stop block position.

[0011] Furthermore, a gap fit is formed between the stop block and the shunt cavity; the temperature sensor is used to detect the temperature of the shape memory alloy and transmit the detected temperature data to the temperature controller, which is used to issue instructions to adjust the current of the resistance wire according to the received temperature data, so as to control the temperature on the shape memory alloy at the target temperature.

[0012] Furthermore, the lateral module assembly also includes a micro motor connected to the end of the connecting rod away from the stop.

[0013] Furthermore, the main cavity extends through one end of the die cavity, and the other end of the main cavity has a stepped mounting hole; the device also includes an ejector rod, one end of which is movably connected to the mounting hole, and is used to eject the completed component from the die cavity.

[0014] The present invention also provides a method for forming a low residual stress component by directional loading, wherein the component is formed using the apparatus described above for forming a low residual stress component by directional loading.

[0015] Furthermore, the downward pressing speed of the punch toward the die is 1 mm / s, and the blank material is pure aluminum.

[0016] In summary, compared with the prior art, the method and apparatus for forming low residual stress components by variable loading provided by the present invention have the following advantages:

[0017] 1. This invention changes the flow direction of the blank during the forming process, so that the internal stresses cancel each other out, reducing the residual stress inside the material. The residual stress is reduced directly during the forming process, eliminating the need for subsequent processes, which greatly improves production efficiency, saves energy, and reduces costs.

[0018] 2. This invention uses the deformation of shape memory alloy as the driving force for the stop, which can save energy; on the other hand, the orientation deformation of the billet requires a large forming force, and the application of shape memory alloy greatly simplifies the structure and cost of the forming device.

[0019] 3. The present invention uses a micro motor to pull the stop back to the initial position, and can repeatedly utilize the deformation of the shape memory alloy to cause the billet to undergo lateral deformation.

[0020] 4. This invention uses a temperature sensor and a displacement sensor to detect the temperature of the shape memory alloy and the position of the baffle, respectively. This allows for real-time adjustment of the current in the resistance wire, precisely controlling the position of the baffle so that the billet in the lateral cavity is completely extruded. Attached Figure Description

[0021] Figure 1 This is a diagram showing the usage state of an apparatus provided by the present invention, which is capable of forming a low residual stress component by variable loading.

[0022] Figure 2 yes Figure 1 Another usage diagram of the device capable of directional loading to form low residual stress components.

[0023] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1-punch, 2-die, 3-blank, 4-displacement sensor, 5-temperature sensor, 6-micro motor, 7-connecting rod, 8-shape memory alloy, 9-resistance wire, 10-stop, 11-ejector rod, 12-flow-dividing cavity, 13-side cavity, 14-temperature controller. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0025] Please see Figure 1 and Figure 2This invention provides an apparatus for forming low residual stress components by variable loading. The apparatus includes a punch 1, a die 2, a side die assembly, a temperature controller 14, and an ejector rod 11. The side die assembly is connected to the die 2. The die 2 has a main cavity and a flow-dividing cavity 12 that are interconnected, with the flow-dividing cavity 12 penetrating the side wall of the main cavity. The punch 1 is detachably connected to the main cavity and is used to extrude a blank 3 into the main cavity and the flow-dividing cavity 12 to pre-form the blank 3. The side die assembly deforms to redirect the material flow at the corner of the pre-formed part, i.e., from the flow-dividing cavity 12 to the main cavity. One end of the ejector rod 11 is movably connected to the die 2 and is used to eject the completed component from the die 2. The movement direction of the punch 1 is perpendicular to the movement direction of the side die assembly. The temperature controller 14 is connected to the side die assembly and is used to control the local temperature of the side die assembly, thereby controlling the amount of deformation. In this embodiment, a low residual stress component refers to a component formed using the above-mentioned device, and the residual stress of the component is significantly reduced; preferably, the residual stress of the low residual stress component is less than 50 MPa.

[0026] The punch 1 is stepped and is used to extrude the original blank 3 into the main cavity of the die 2 and the flow-dividing cavity 12. During the extrusion process, the blank 3 partially flows from the main cavity into the flow-dividing cavity 12. The stepped punch 1 can flatten the upper surface of the component.

[0027] The die cavity 2 also has a lateral cavity 13, which communicates with the flow-dividing cavity 12. The flow-dividing cavity 12 is located between the lateral cavity 13 and the main cavity. The lateral cavity 13 is used to accommodate the lateral mold assembly. In this embodiment, the central axis of the main cavity coincides with the central axis of the die cavity 2. The number of flow-dividing cavities 12, the number of lateral cavities 13, and the number of lateral mold assemblies are the same, and there are multiple of each. Preferably, the number of flow-dividing cavities 12 is even, and the multiple flow-dividing cavities 12 are symmetrically arranged with respect to the central axis of the main cavity. The main cavity extends through one end of the die cavity 2, and the other end of the main cavity has a stepped mounting hole, which communicates with the main cavity. The mounting hole is used to accommodate the ejector rod 11. Specifically, the ejector rod 11 is stepped, and one end is movably connected to the mounting hole.

[0028] The lateral mold assembly includes a temperature sensor 5, a displacement sensor 4, a resistance wire 9, a connecting rod 7, a stop block 10, and a micro motor 6. The temperature sensor 5, the displacement sensor 4, and the resistance wire 9 are respectively connected to the temperature controller 14. The displacement sensor 4 is disposed on the inner wall of the lateral cavity 13. One end of the connecting rod 7 extends into the lateral cavity 13 and is connected to the stop block 10, and the other end is connected to the micro motor 6. The micro motor 6 is located outside the concave mold 2, and the stop block 10 is located inside the concave mold 2. A shape memory alloy 8 is disposed on the connecting rod 7, and the shape memory alloy 8 forms a cylindrical body. The temperature sensor 5 and the resistance wire 9 are disposed on the shape memory alloy 8.

[0029] The two opposite ends of the connecting rod 7 are respectively machined with external threads, which are connected to the micro motor 6 and the stop block 10 respectively. The stop block 10 and the flow-dividing cavity 12 form a clearance fit. The resistance wire 9 is wound around the outside of the shape memory alloy 8.

[0030] The temperature sensor 5 is used to detect the temperature of the shape memory alloy 8 and transmit the detected temperature data to the temperature controller 14. The temperature controller 14 is used to issue instructions to adjust the current of the resistance wire 9 according to the received temperature data, so as to control the temperature on the shape memory alloy 8 at the target temperature.

[0031] The displacement sensor 4 is used to measure the position of the stop 10 and transmit the measured position data to the temperature controller 14. The temperature controller 14 is used to adjust the current of the resistance wire 9 in real time according to the received position data, thereby controlling the deformation of the shape memory alloy 8, so that the stop 10 just fills the gap of the shunt cavity 12.

[0032] The present invention also provides a method for forming a low residual stress component by variable loading, the method mainly comprising the following steps:

[0033] Step 1: Provide the device described above that can be oriented to form a low residual stress component by loading, so that the temperature of the shape memory alloy 8 is at room temperature, start the micro motor 6, and pull the stop block 10 to the end of the lateral cavity 13 away from the main cavity through the connecting rod 7.

[0034] Step 2: Install the blank 3 onto the die 2, and move the punch 1 toward the die 2 to squeeze the blank 3, so that the blank 3 is squeezed into the main cavity and partially enters the branch cavity 12, thus completing the pre-forming of the blank 3.

[0035] Step 3: Keeping the position of the punch 1 unchanged, the heating resistance wire 9 causes the shape memory alloy 8 to elongate and deform, pushing the stop 10 towards the main cavity. This causes the blank 3 in the diversion cavity 12 to flow in the opposite direction, filling the area between the punch 1 and the ejector rod 11 in the main cavity of the die 2. The temperature controller 14 adjusts the current in the resistance wire 9 based on data from the temperature sensor 5, and simultaneously limits the current in the resistance wire 9 based on data from the displacement sensor 4. Ultimately, the temperature of the shape memory alloy 8 reaches the set temperature, pushing the stop 10 until it contacts the inner wall of the die 2.

[0036] Step four: The pre-formed part after pretreatment is ejected from the die 2 by the ejector rod 11. In this embodiment, the downward pressing speed of the punch 1 is 1 mm / s, and the material of the blank 3 is pure aluminum.

[0037] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A device capable of shaping a low residual stress component by variable-direction loading, characterized in that: The device includes a punch, a die, and a side die assembly. The side die assembly is disposed on the die. The die has a main cavity and a branch cavity that are connected to each other. The branch cavity penetrates the side wall of the main cavity. The punch is detachably connected to the main cavity and is used to extrude the blank into the main cavity and the branch cavity to complete the pre-forming of the blank. The lateral mold assembly deforms to redirect the material flow at the corner of the preform, thereby pushing the blank in the split cavity into the main cavity.

2. The apparatus for forming a low residual stress component by variable loading as described in claim 1, characterized in that: The device also includes a temperature controller connected to the side mold assembly, which controls the local temperature of the side mold assembly, thereby controlling the amount of deformation so that the blank in the split mold cavity is just completely extruded into the main mold cavity.

3. The apparatus for forming a low residual stress component by variable loading as described in claim 2, characterized in that: The die cavity also has a lateral cavity, which is connected to the flow-dividing cavity and is located between the lateral cavity and the main cavity; the lateral cavity is used to accommodate the lateral die assembly.

4. The apparatus for forming a low residual stress component by variable loading as described in claim 3, characterized in that: The lateral module assembly includes a temperature sensor, a displacement sensor, a resistance wire, a stop block, and a connecting rod. The temperature sensor, the displacement sensor, and the resistance wire are respectively connected to the temperature controller. The displacement sensor is disposed on the inner wall of the lateral cavity. One end of the connecting rod extends into the lateral cavity and is connected to the stop block. A shape memory alloy is disposed on the connecting rod, and the shape memory alloy forms a cylindrical body. The temperature sensor and the resistance wire are disposed on the shape memory alloy.

5. The apparatus for forming a low residual stress component by variable loading as described in claim 4, characterized in that: The temperature sensor and the displacement sensor are used to detect the temperature of the shape memory alloy and the position of the stop block, respectively, and transmit the detected temperature data and position data to the temperature controller; the temperature controller is used to adjust the current in the resistance wire in real time according to the received temperature data and position data, so as to control the deformation of the shape memory alloy and realize the control of the stop block position.

6. The apparatus for forming a low residual stress component by variable loading as described in claim 4, characterized in that: The baffle and the shunt cavity form a gap fit; the temperature sensor is used to detect the temperature of the shape memory alloy and transmit the detected temperature data to the temperature controller, which is used to issue instructions to adjust the current of the resistance wire according to the received temperature data, so as to control the temperature on the shape memory alloy at the target temperature.

7. The apparatus for forming a low residual stress component by variable loading as described in claim 4, characterized in that: The lateral module assembly also includes a micro motor connected to the end of the connecting rod away from the stop.

8. The apparatus for forming a low residual stress component by variable loading as described in any one of claims 1-7, characterized in that: The main cavity extends through one end of the die cavity, and the other end of the main cavity has a stepped mounting hole; the device also includes an ejector rod, one end of which is movably connected to the mounting hole, and is used to eject the completed component from the die cavity.

9. A method for forming a low residual stress component by variable-direction loading, characterized in that: This method uses the apparatus described in any one of claims 1-8, which is capable of directional loading to form low residual stress components, to form components.

10. The method for forming a low residual stress component by variable-direction loading as described in claim 9, characterized in that: The punch presses down toward the die at a speed of 1 mm / s, and the blank is made of pure aluminum.

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