Electro-arc additive manufacturing method of aluminum alloy runner

Abstract

The application relates to an arc additive manufacturing method of an aluminum alloy runner. A conventional technology is to adopt a five-axis linkage numerical control system for machining a complex curved surface to machine out the whole runner from an aluminum alloy blank, the manufacturing method has low material utilization, a long machining period and high production cost of the aluminum alloy runner. The application adopts a mode of additive manufacturing of aluminum alloy blades in partial segments on the surface of a regular cylinder and mechanical machining of a runner shaft and a blade root joint surface on a numerical control machine tool, cracks caused by stress concentration at the interface between the runner shaft and the additive blade are avoided, the product quality is ensured, the production cost of the aluminum alloy runner is greatly reduced, and the machining period is shortened. The application relates to the arc additive manufacturing method of the aluminum alloy runner.

Description

Technical fields:

[0001] This invention relates to an electric arc additive manufacturing method for an aluminum alloy rotary wheel. Background technology:

[0002] Aluminum alloy rotors are rotating components consisting of a shaft and aluminum alloy blades. They are commonly used in important power components in aerospace and shipbuilding. The blade shape of aluminum alloy rotors is a curved surface with large torsion, and the machining drawings are complex. The conventional manufacturing method is to use a five-axis linkage CNC system to machine the rotor as a whole on a block of aluminum alloy blank. This manufacturing method has low material utilization, long processing cycle, and high production cost of aluminum alloy rotors.

[0003] However, the additive manufacturing process on the surface of aluminum alloy rotors is a multi-layer, multi-pass aluminum alloy MIG welding process. The interface between the rotor blades and the rotor shaft is subjected to complex forces, and the stress concentration is large, which can easily cause cracks, leading to the failure of the additive rotor. Summary of the Invention:

[0004] The purpose of this invention is to provide an electric arc additive manufacturing method for aluminum alloy rotary wheels. This method can reduce repeated five-axis machine tool processing steps, has a high material utilization rate, can significantly reduce the production cost of aluminum alloy rotary wheels, shorten the processing cycle, and improve work efficiency.

[0005] The above objectives are achieved through the following technical solutions:

[0006] An arc additive manufacturing method for an aluminum alloy rotor includes the following steps: adding aluminum alloy blades in sections on the surface of a regular cylinder and machining the interface between the rotor shaft and the blade root on a CNC machine tool to avoid cracking caused by stress concentration at the interface between the rotor shaft and the additive blade. The specific steps are as follows:

[0007] Step 1: Prepare an aluminum alloy cylinder with a central hole. The aluminum alloy cylinder has a machining allowance of 5mm to 10mm in the diameter and length directions relative to the shaft. The diameter of the cylinder surface is such that during precision machining, the radial distance between the blade root B, which is closer to the coarser section A, and the cylinder surface is greater than 10mm.

[0008] The diameter of the cylindrical center hole is 2mm to 5mm smaller than the diameter of the center hole of the rotor to be manufactured, and the number of blades near the rotor to be manufactured is not limited to the top. Figure 1 The number shown indicates that the surface of the rotating shaft can be a conical surface or a cylindrical surface;

[0009] Step 2: Connect the two ends of the central hole of the aluminum alloy cylinder that meets the requirements of Step 1 through pipes to make a circulating water device. The two sides of the central hole are sealed to ensure no water leakage. During the electric arc additive process, the maximum temperature of the aluminum alloy cylinder surface is kept below 50°C by controlling the water temperature, flow rate and additive cooling time.

[0010] Step 3: Draw an aluminum alloy cylinder in the three-dimensional digital model of the rotary wheel, and use the surface of the aluminum alloy cylinder as the reference plane and parallel offset plane for the blade slicing. Slice the blade, plan the single-layer electric arc additive trajectory, and generate position information. The spacing between parallel trajectories in the single layer is amm, where a=4~8.

[0011] Step 4: When the axial offset of the starting position of the blade layer in Step 3 relative to the previous layer after additive manufacturing is Δd < a / 2 mm, the layer is continuously additively manufactured. When Δd > a / 2 mm, the interlayer is processed in segments to control the heat input during the continuous welding process of the aluminum alloy. Between the blades, the blades are processed in an intermittent manner. That is, after the single-layer blade is additively manufactured, the aluminum alloy cylinder rotates at a certain angle to reach the interstitial blade, and the additive manufacturing of the slice layer is completed in the same way. This process is repeated to complete the additive manufacturing of each blade and each slice layer.

[0012] Step 5: Machining and polishing to meet the delivery requirements of the rotary product.

[0013] Beneficial effects:

[0014] 1. This invention is an arc additive manufacturing method for aluminum alloy rotary wheels. The method involves adding aluminum alloy blades in sections on the surface of a regular cylinder during the manufacturing process of the aluminum alloy rotary wheel, and machining the interface between the shaft and the blade root on a CNC machine tool. This avoids cracking caused by stress concentration at the interface between the shaft and the additive blade, ensuring product quality, while significantly reducing the production cost of aluminum alloy rotary wheels and shortening the processing cycle.

[0015] 2. This invention addresses the fact that the connection between the blades and the cylindrical shaft is a complex area prone to stress concentration and cracking. By employing cold working, it avoids quality problems caused by defects such as porosity and inclusions introduced during aluminum alloy welding. The aluminum alloy cylinder is manufactured to a size that can be machined on a single-axis machine tool, which is simple and feasible, reducing repeated five-axis machine tool processing steps. The rotor blades are manufactured using arc additive manufacturing, which can significantly reduce the production cost of aluminum alloy rotors, shorten the processing cycle, and improve efficiency. Attached image description:

[0016] Appendix Figure 1 This is a three-dimensional schematic diagram of the aluminum alloy rotor model of the present invention.

[0017] Appendix Figure 2 It is attached Figure 1Schematic diagram of the orientation of the middle blade.

[0018] Appendix Figure 3 This is a schematic diagram of a slice on an aluminum alloy cylindrical surface.

[0019] The components are: 1. blade, 2. shaft, 3. center hole of the rotor, and 4. aluminum alloy cylinder. Detailed implementation method:

[0020] Example 1:

[0021] An arc additive manufacturing method for an aluminum alloy rotor includes the following steps: adding aluminum alloy blades in sections on the surface of a regular cylinder and machining the interface between the rotor shaft and the blade root on a CNC machine tool to avoid cracking caused by stress concentration at the interface between the rotor shaft and the additive blade. The specific steps are as follows:

[0022] Step 1: Prepare an aluminum alloy cylinder with a central hole. The aluminum alloy cylinder has a machining allowance of 5mm to 10mm in the diameter and length directions relative to the shaft. The diameter of the cylinder surface is such that during precision machining, the radial distance between the blade root B, which is closer to the coarser section A, and the cylinder surface is greater than 10mm.

[0023] The diameter of the cylindrical center hole is 2mm to 5mm smaller than the diameter of the center hole of the rotor to be manufactured, and the number of blades near the rotor to be manufactured is not limited to the top. Figure 1 The number shown indicates that the surface of the rotating shaft can be a conical surface or a cylindrical surface;

[0024] Step 2: Connect the two ends of the central hole of the aluminum alloy cylinder that meets the requirements of Step 1 through pipes to make a circulating water device. The two sides of the central hole are sealed to ensure no water leakage. During the electric arc additive process, the maximum temperature of the aluminum alloy cylinder surface is kept below 50°C by controlling the water temperature, flow rate and additive cooling time.

[0025] Step 3: Draw an aluminum alloy cylinder in the three-dimensional digital model of the rotary wheel, and use the surface of the aluminum alloy cylinder as the reference plane and parallel offset plane for the blade slicing. Slice the blade, plan the single-layer electric arc additive trajectory, and generate position information. The spacing between parallel trajectories in the single layer is amm, where a=4~8.

[0026] Step 4: When the axial offset of the starting position of the blade layer in Step 3 relative to the previous layer after additive manufacturing is Δd < a / 2 mm, the layer is continuously additively manufactured. When Δd > a / 2 mm, the interlayer is processed in segments to control the heat input during the continuous welding process of the aluminum alloy. Between the blades, the blades are processed in an intermittent manner. That is, after the single-layer blade is additively manufactured, the aluminum alloy cylinder rotates at a certain angle to reach the interstitial blade, and the additive manufacturing of the slice layer is completed in the same way. This process is repeated to complete the additive manufacturing of each blade and each slice layer.

[0027] Step 5: Machining and polishing to meet the delivery requirements of the rotary product.

Claims

1. An electric arc additive manufacturing method for an aluminum alloy rotary wheel, characterized in that: This method includes the following steps: using segmented additive aluminum alloy blades on the surface of a regular cylinder and machining the interface between the shaft and the blade root on a CNC machine tool to avoid cracking caused by stress concentration at the interface between the shaft and the additive blade. The specific steps are as follows: Step 1: Prepare an aluminum alloy cylinder with a central hole. The aluminum alloy cylinder has a machining allowance of 5mm to 10mm in the diameter and length directions relative to the shaft. The diameter of the cylinder surface is such that during precision machining, the radial distance between the blade root B, which is closer to the coarser section A, and the cylinder surface is greater than 10mm. The diameter of the cylindrical center hole is 2mm to 5mm smaller than the diameter of the center hole of the rotating wheel to be manufactured, and the surface of the rotating shaft is a conical surface or a cylindrical surface; Step 2: Connect the two ends of the central hole of the aluminum alloy cylinder that meets the requirements of Step 1 through pipes to make a circulating water device. The two sides of the central hole are sealed to ensure no water leakage. During the electric arc additive process, the maximum temperature of the aluminum alloy cylinder surface is kept below 50°C by controlling the water temperature, flow rate and additive cooling time. Step 3: Draw an aluminum alloy cylinder in the three-dimensional digital model of the rotary wheel, and use the surface of the aluminum alloy cylinder as the reference plane and parallel offset plane for the blade slicing. Slice the blade, plan the single-layer electric arc additive trajectory, and generate position information. The spacing between parallel trajectories in the single layer is amm, where a=4~8. Step 4: When the axial offset of the starting position of the slice layer in Step 3 relative to the previous layer after additive manufacturing is Δd < a / 2 mm, the whole layer continuous additive manufacturing method is adopted within the layer. When Δd > a / 2 mm, the interlayer adopts the segmented processing method to control the heat input of the continuous welding process of aluminum alloy. Between the rotor blades, the interval processing method is adopted. That is, after the single-layer blade is additively manufactured, the aluminum alloy cylinder rotates at a certain angle to reach the interval blade, and the additive manufacturing of the slice layer is completed in the same way. This process is repeated to complete the additive manufacturing of each slice layer of each blade. Step 5: Machining and polishing to meet the delivery requirements of the rotary product.

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