Waste heat shaping process after high-temperature injection molding of magnesium alloy sheet structural part
By using the residual heat shaping process after high-temperature injection molding of magnesium alloy sheet structural parts, residual stress is eliminated by utilizing residual heat, which solves the problem of high energy consumption in existing technologies and achieves efficient shaping and product quality assurance.
Patent Information
- Application Number
- CN202511121180.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-12
- Publication Date
- 2025-11-11
AI Technical Summary
The residual stress caused by uneven cooling rate and mold pressure differences in the existing magnesium alloy sheet structural parts manufacturing process requires two hot forming processes, which increases energy consumption and manufacturing costs.
The process employs a high-temperature injection molding followed by residual heat shaping, utilizing the residual heat of the magnesium alloy sheet structure for shaping. A robotic arm clamps the sheet at 120-140℃ into a shaping mold, applying a pressure of 0.5±0.1MPa for 20±10 seconds to eliminate residual stress.
This reduces the need for heating equipment in the shaping machine, saves energy consumption, and ensures product quality through waste heat shaping, thereby improving production efficiency and product precision.
Smart Images
Figure CN120920547A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of magnesium alloy sheet structure manufacturing technology, specifically to a residual heat shaping process for magnesium alloy sheet structure after high-temperature injection molding. Background Technology
[0002] High-temperature injection molding process for magnesium alloy sheet structural parts: Based on the semi-solid thixotropic properties of magnesium alloy, granular magnesium alloy raw materials are heated and subjected to shear force to form a semi-solid slurry, which is then injected into the mold cavity at high speed to form the part.
[0003] Shaping process: The shaping process of metal structural parts is a technology that uses external force or heating to correct the shape of deformed magnesium alloy sheet structural parts, so as to restore them to their designed dimensions and accuracy.
[0004] In the existing technology, the production process of magnesium alloy sheet structural parts, such as magnesium alloy notebook shell parts, is as follows: after high-temperature injection molding, the material is unloaded by a robot. After the magnesium alloy notebook shell parts cool down, they are punched by a press, hot-shaped by a forming machine, CNC machining, fine polishing, chemical forming, a second hot-shaped by a forming machine, and then packaged.
[0005] During injection molding of magnesium alloy sheet components, uneven cooling rates and mold pressure differences can generate residual stress within the components, leading to localized warping, twisting, or exceeding flatness standards (e.g., screen bezel deformation, bottom surface arching). Therefore, shaping is an unavoidable process. In existing manufacturing processes, to eliminate residual stress within the metal and ensure dimensional accuracy, magnesium alloy sheet components require hot shaping. Hot shaping involves a shaping machine equipped with heating elements, applying pressure during the heating process. Using existing technology, two hot shaping operations are required, each requiring two heating cycles. A typical hot shaping machine for magnesium alloy sheet components, such as those used in laptop magnesium alloy casings, has a total heating element power of approximately 10 kilowatts. Working 8 hours a day, this results in a daily power consumption of 10 × 8 = 80 kilowatt-hours. Assuming a standard 250-day working year, this amounts to 80 * 250 = 20,000 kilowatt-hours per year. This is just the annual power consumption of one heat forming machine. For a large enterprise that produces millions of magnesium alloy laptop shell parts a year, dozens of heat forming machines need to work simultaneously, consuming millions of kilowatt-hours of electricity per year, which increases manufacturing costs and leads to energy waste. Summary of the Invention
[0006] The purpose of this invention is to propose a residual heat shaping process for magnesium alloy sheet structural parts after high-temperature injection molding.
[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A residual heat shaping process for magnesium alloy sheet structural parts after high-temperature injection molding includes the following steps: (1) The granular magnesium alloy raw material is heated to 560-610℃ through a magnesium alloy thixotropic molding machine to make a semi-solid slurry, and then injected into the mold cavity at high speed to form a magnesium alloy sheet structure. (2) When the magnesium alloy thixotropic molding machine opens the mold in step (1), the robot takes out the magnesium alloy sheet structure made in step (1) and places it on the production line and transports it to the next step. The temperature of the magnesium alloy sheet structure will be cooled during the conveying process on the production line. (3) When the magnesium alloy sheet structure on the production line of step (2) arrives at the forming station and the temperature is cooled to 120-140℃, the robot clamps the magnesium alloy sheet structure into the forming mold of the forming machine and presses it. The pressing time is 20±10 seconds and the pressure is 0.5±0.1MPa. (4) When the forming mold of the forming machine in step (3) opens and closes, the robot takes out the magnesium alloy sheet structure from step (3), thus completing the forming of the magnesium alloy sheet structure and the release of residual stress.
[0008] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a residual heat shaping process for magnesium alloy sheet structural parts after high-temperature injection molding. This process utilizes the residual heat after high-temperature injection molding for shaping, eliminating the need for heating elements in the shaping machine and saving energy. Furthermore, the optimized shaping process allows for timely shaping of the magnesium alloy sheet structural parts after injection molding. By employing the principle of "reverse pressure," controllable external force can be applied to the magnesium alloy sheet structural parts to counteract residual deformation after molding, ensuring product quality. Attached Figure Description
[0009] Figure 1 This is a schematic diagram of the prior art process of the present invention; Figure 2 This is a schematic diagram of the process flow of the present invention. Detailed Implementation
[0010] See appendix Figure 1 In the existing technology, the hot forming process for magnesium alloy sheet structures is carried out after punching, that is, after the magnesium alloy sheet structure has cooled down.
[0011] Participate in the attached Figure 2 The present invention discloses a residual heat shaping process for magnesium alloy sheet structural parts after high-temperature injection molding, comprising the following steps: (1) The granular magnesium alloy raw material is heated to 560-610℃ through a magnesium alloy thixotropic molding machine to make a semi-solid slurry, and then injected into the mold cavity at high speed to form a magnesium alloy sheet structure. (2) When the magnesium alloy thixotropic molding machine opens the mold in step (1), the robot takes out the magnesium alloy sheet structure made in step (1) and places it on the production line and transports it to the next step. The temperature of the magnesium alloy sheet structure will be cooled during the conveying process on the production line. (3) When the magnesium alloy sheet structure on the production line of step (2) arrives at the forming station and the temperature is cooled to 120-140℃, the robot clamps the magnesium alloy sheet structure into the forming mold of the forming machine and presses it. The pressing time is 20±10 seconds and the pressure is 0.5±0.1MPa. (4) When the forming mold of the forming machine in step (3) opens and closes, the robot takes out the magnesium alloy sheet structure from step (3), thus completing the forming of the magnesium alloy sheet structure and the release of residual stress.
[0012] The working principle of the process is as follows: Step (1): The granular magnesium alloy raw material is heated to 560-610℃ through a magnesium alloy thixotropic molding machine to make a semi-solid slurry, and then injected into the mold cavity at high speed to form a magnesium alloy sheet structure. This is the semi-solid production process of magnesium alloy sheet structure, and the equipment used is a magnesium alloy thixotropic molding machine.
[0013] Step (2): When the magnesium alloy thixotropic molding machine opens the mold in step (1), the robot takes out the magnesium alloy sheet structure made in step (1) and places it on the production line and transports it to the next step. The temperature of the magnesium alloy sheet structure will cool down during the transportation process on the production line. Since the magnesium alloy thixotropic molding machine is heated to a very high temperature during the semi-solid injection process in step (1), if the shaping is carried out under high temperature conditions, it will not only require the configuration of higher-specification heating equipment, increasing energy consumption and equipment costs, but also make it difficult to control the cooling rate of the parts after high-temperature shaping, which may cause new deformation due to thermal stress.
[0014] Step (3): When the magnesium alloy sheet structure from step (2) arrives at the forming station and the temperature cools to 120-140℃, the robot clamps the magnesium alloy sheet structure into the forming mold of the forming machine and presses it. The pressing time is 20±10 seconds and the pressure is 0.5±0.1MPa. Therefore, after a lot of testing and repeated experiments, magnesium alloy sheet structure, such as magnesium alloy notebook shell parts, can be plastically deformed in a temperature range of 120-140℃, which is lower than the melting point of magnesium alloy. This temperature range can avoid the risk of melting caused by excessive temperature.
[0015] Step (4): (4) When the forming mold of the forming machine in step (3) opens and closes, the robot takes out the magnesium alloy sheet structure from step (3), thus completing the forming and residual stress release of the magnesium alloy sheet structure. By applying a pressure of 0.5±0.1MPa and holding it for 20±10 seconds, the plastic deformation characteristics of the metal material can be utilized. By applying pressure and combining it with residual heat, the deformed part can generate reverse plastic flow, which can offset the original deformation and ensure the product quality of the magnesium alloy sheet structure.
[0016] To eliminate residual stress within the metal and ensure dimensional accuracy of the product, magnesium alloy sheet structural parts must undergo a hot forming process during production. This invention provides a residual heat forming process for magnesium alloy sheet structural parts after high-temperature injection molding. This process utilizes the residual heat after high-temperature injection molding for shaping, eliminating the need for heating elements in the forming machine, thus saving energy. Furthermore, the optimized forming process allows for timely shaping of the magnesium alloy sheet structural parts after injection molding. By employing the principle of "reverse pressure," controllable external force can be applied to the magnesium alloy sheet structural parts to counteract residual deformation after molding, ensuring product quality.
[0017] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.
Claims
1. A residual heat shaping process for magnesium alloy sheet structural parts after high-temperature injection molding, characterized in that: Includes the following steps: (1) The granular magnesium alloy raw material is heated to 560-610℃ through a magnesium alloy thixotropic molding machine to make a semi-solid slurry, and then injected into the mold cavity at high speed to form a magnesium alloy sheet structure. (2) When the magnesium alloy thixotropic molding machine opens the mold in step (1), the robot takes out the magnesium alloy sheet structure made in step (1) and places it on the production line and transports it to the next step. The temperature of the magnesium alloy sheet structure will be cooled during the conveying process on the production line. (3) When the magnesium alloy sheet structure on the production line of step (2) arrives at the forming station and the temperature is cooled to 120-140℃, the robot clamps the magnesium alloy sheet structure into the forming mold of the forming machine and presses it. The pressing time is 20±10 seconds and the pressure is 0.5±0.1MPa. (4) When the forming mold of the forming machine in step (3) opens and closes, the robot takes out the magnesium alloy sheet structure from step (3), thus completing the forming of the magnesium alloy sheet structure and the release of residual stress.