Low-pressure casting exhaust system for aluminum alloy lower shell

Abstract

The invention discloses an aluminum alloy lower shell low-pressure casting exhaust system, and relates to the technical field of aluminum alloy lower shell low-pressure casting. By using the exhaust part, the upper mold and the lower mold can be conveniently knocked to vibrate, so that gas in solutions in the upper mold and the lower mold can be conveniently exhausted, the adverse effect of bubbles is reduced, and the production quality of the aluminum alloy lower shell is improved; the analysis module analyzes the relationship among the knocking strength, the telescopic speed of the micro electric telescopic rod, the load and the environment temperature, establishes a relational expression and combines data collected by the collection module, so that the knocking strength can be accurately determined, the problem that the knocking strength is not accurately controlled due to the fact that parameters are set according to experience in a traditional mode is solved, and the working efficiency is improved. The situation that air cannot be effectively exhausted due to insufficient force is avoided, the situation that the mold is damaged due to too large force is avoided, and the system can automatically adjust the knocking force and position according to different loads, environment temperature changes and casting liquid temperature conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of low-pressure casting of aluminum alloy lower shells, and particularly relates to a low-pressure casting exhaust system for aluminum alloy lower shells. Background Art

[0002] The low-pressure casting of aluminum alloy lower shells is a precision forming process, especially suitable for components with complex structures, high airtightness requirements or high mechanical properties. When performing low-pressure casting on aluminum alloy lower shells, a low-pressure casting device is required; However, when the existing low-pressure casting device is in use, since bubbles will be generated in the molten metal in the mold, and these bubbles form cavities after the molten metal cools, which affects the quality of the aluminum alloy lower shell; In the traditional method, the operating parameters of the electric push rod are mostly set by experience to control the knocking force, resulting in inaccurate control of the knocking force. During the exhaust process, either due to insufficient knocking force, the surface tension of the bubbles in the casting liquid cannot be effectively broken, making it difficult to discharge the bubbles; or the knocking force is too large, causing irreversible damage to the casting mold. Summary of the Invention

[0003] The present invention provides a low-pressure casting exhaust system for aluminum alloy lower shells to solve the problems in the background art.

[0004] To achieve the above object, the present invention adopts the following technical solutions: A low-pressure casting exhaust system for aluminum alloy lower shells includes a workbench, columns arranged at the four corners of the top surface of the workbench, and a top cover arranged on the top of the columns. A support one is arranged on the top surface of the workbench, and a lower mold is arranged on the top of the support one; An electric push rod is arranged on the top cover. An installation plate is arranged at the movable end of the electric push rod, and an upper mold matched with the lower mold is arranged on the bottom surface of the installation plate; An exhaust member is also arranged on the top surface of the workbench; A intelligent control component is also arranged inside the control box of the exhaust system. The intelligent control component includes an analysis module; The analysis module analyzes the relationship between the knocking force and the telescopic speed, load and ambient temperature of the micro electric telescopic rod, substitutes the detection data of the corresponding items to obtain the relationship formula of the knocking force with respect to the telescopic speed, load and ambient temperature; analyzes the temperature data of the casting liquid inside the mold, determines the knocking position and the required knocking force, and generates a knocking signal, and transmits the knocking signal to the execution module.

[0005] Preferably, the exhaust member includes support two symmetrically arranged on the top surface of the workbench and a rectangular box arranged on the top surface of the support two. A micro electric telescopic rod is arranged inside the rectangular box, a knocking block is arranged at the movable end of the micro electric telescopic rod, and a plurality of air outlet holes are arranged on the top surface of the upper mold.

[0006] Preferably, a sponge is provided on the knocking block.

[0007] Preferably, a plurality of guide rods are provided between the workbench and the top cover, and the mounting plate is slidably arranged between the guide rods.

[0008] Preferably, the intelligent control component further includes a collection module and an execution module; The collection module detects the knocking force of the knocking block, detects the telescopic speed data, load data and ambient temperature data corresponding to the knocking force, detects the temperature data of the casting liquid inside the mold, and transmits the detected data to the analysis module; The execution module receives the knocking signal transmitted by the analysis module and performs a knocking operation with a corresponding knocking force according to the transmitted knocking position data.

[0009] Preferably, the analysis steps of the load of the micro electric telescopic rod by the analysis module are as follows: S1: Measure the output voltage of the bridge, and the relative change in the resistance of the strain gauge and the strain The relationship between: , is the resistance change, is the initial resistance value of the strain gauge, is the sensitivity coefficient of the strain gauge; S2: The output voltage of the bridge and the change in the resistance of the strain gauge The relationship between: , is the power supply voltage of the bridge, then the strain can be deduced; within the elastic range, the stress and the strain The relationship between: , is the elastic modulus of the material of the force-bearing part of the micro electric telescopic rod; the cross-sectional area of the force-bearing part of the micro electric telescopic rod is , the load force , the load force is deduced .

[0010] Preferably, the analysis steps of the knocking force relational expression by the analysis module are as follows: N1: Sort the collected knocking force data, telescopic speed data, load data and ambient temperature data according to the collection time, and average the data of the corresponding items detected at the same time and standard deviation are calculated, and the calculated average value and standard deviation Set the fluctuation range of the detection data, and the fluctuation range is . Record the data that are not within the fluctuation range among the data of the corresponding items detected at the same time as outliers, and count the number of outliers; N2: If the preset proportion threshold , it is determined that the detection data is not accurate, and the corresponding item data detected at this time point is marked as abnormal; otherwise, remove the outliers, calculate the mean value of the remaining detection data, use the calculated mean value as the corresponding item detection data at this time point, and then establish a data set corresponding to the acquisition time. Each data set corresponds to an acquisition time, and the data set contains the tapping force data, as well as the telescopic speed data, load data, and ambient temperature data corresponding to the tapping force data; N3: Establish a relationship model of the tapping force with respect to the telescopic speed , load and ambient temperature : , , , , are regression coefficients; N4: Substitute the tapping force data, telescopic speed data, load data, and ambient temperature data in the data set into the relationship formula of the tapping force , calculate the regression coefficients, and substitute the calculated regression coefficients into the relationship formula of the tapping force . When the load and ambient temperature do not change much, obtain the relationship formula of the tapping force with respect to the telescopic speed of the micro electric telescopic rod.

[0011] Preferably, the steps for the analysis module to analyze the casting liquid temperature are as follows: M1: Establish a two-dimensional coordinate system of the temperature data and the acquisition time, plot and connect the corresponding coordinate points in the coordinate system, calculate the slope of each connected line, and compare the slope of the connected line with the preset change threshold. Determine that the temperature change amplitude of the corresponding connected line time period with a slope less than the preset change threshold is less than the normal value, obtain the mold position corresponding to the temperature probe, and record the corresponding connected line time period as the bubble time period; Compare the slope of the connected line in the adjacent time period of the bubble time period of the temperature probe with the preset change threshold. If the slope of the connected line in the adjacent time period of the bubble time period is less than the preset change threshold, perform a stability count, and for each detected adjacent time period with a slope of the connected line less than the preset change threshold, add 1 to the stability count of the corresponding bubble time period; ​M2: Mark the positions of the temperature probes with stable counts greater than the preset count threshold, generate a tapping signal, and transmit the tapping signal to the execution module; M3: The connection slope for the corresponding time period is compared with the preset change threshold to calculate the specific value of , and the calculated specific value is compared with the preset step thresholds , , , , . Each preset step threshold corresponds to a tapping force. If , it is determined to adopt the corresponding tapping force.

[0012] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are as follows: 1. By using the exhaust component, it is convenient to tap the upper die and the lower die to make them vibrate, thereby facilitating the discharge of gas in the solutions inside the upper die and the lower die, reducing the adverse effects of bubbles, and thus improving the quality of the production of the aluminum alloy lower housing; 2. By analyzing the relationship between the tapping force and the telescopic speed, load, and ambient temperature of the micro electric telescopic rod by the analysis module, establishing a relational expression and combining the data collected by the acquisition module, the tapping force can be accurately determined, avoiding the problem of inaccurate control of the tapping force caused by setting parameters based on experience in the traditional method. It will neither fail to effectively exhaust due to insufficient force nor damage the die due to excessive force, and the system can automatically adjust the tapping force and position according to different loads, ambient temperature changes, and casting liquid temperature conditions, and has strong adaptability to different casting conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 shows a schematic structural diagram in the front view according to an embodiment of the present invention; Figure 2 shows a schematic structural diagram of the exhaust component according to an embodiment of the present invention; Figure 3 shows a schematic structural diagram of the upper die according to an embodiment of the present invention; Figure 4 shows a system flow chart according to an embodiment of the present invention.

[0014] Legend Explanation: 1. Workbench; 2. First support; 3. Lower mold; 4. Upper mold; 5. Mounting plate; 6. Electric push rod; 7. Top cover; 8. Guide rod; 9. Support pillar; 10. Rectangular box; 11. Second support; 12. Micro electric telescopic rod; 13. Knocking block; 14. Air vent; 15. Sponge. Detailed implementation manner

[0015] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0016] Please refer to Figure 1 - Figure 4 , the present invention provides a technical solution: A low-pressure casting exhaust system for an aluminum alloy lower shell, including a workbench 1, support pillars 9 arranged at the four corners of the top surface of the workbench 1, and a top cover 7 arranged at the top of the support pillars 9. A first support 2 is fixedly installed on the top surface of the workbench 1 by bolts, and the first support 2 is located in the middle of the top surface of the workbench 1 for installing the lower mold 3; the lower mold 3 is arranged on the top of the first support 2; An electric push rod 6 is fixedly installed on the top cover 7 by bolts, which is used to push the upper mold 4 downward, so as to facilitate the clamping of the upper mold 4 and the lower mold 3, and further facilitate the low-pressure die casting of the aluminum alloy shell; the movable end of the electric push rod 6 is provided with a mounting plate 5, and the mounting plate 5 is fixedly installed on the movable end of the electric push rod 6 by bolts or welding for installing the upper mold 4; the upper mold 4 that cooperates with the lower mold 3 is arranged on the bottom surface of the mounting plate 5; An exhaust member is also arranged on the top surface of the workbench 1. By using the exhaust member, it is convenient to knock the upper mold 4 and the lower mold 3 to make them vibrate, so as to facilitate the discharge of the gas in the internal solution of the upper mold 4 and the lower mold 3, avoid the generation of bubbles, and thus improve the quality of the production of the aluminum alloy lower shell.

[0017] In the present invention, the exhaust member includes two brackets 11 symmetrically arranged on the top surface of the workbench 1, and the two brackets 11 are fixed to the top surface of the workbench 1 by bolts for the installation of the rectangular box 10; the rectangular box 10 is arranged on the top surface of the two brackets 11, and the rectangular box 10 is installed on the two brackets 11 by bolts; a micro electric telescopic rod 12 is arranged inside the rectangular box 10, a knocking block 13 is arranged at the movable end of the micro electric telescopic rod 12, and a plurality of air outlet holes 14 are arranged on the top surface of the upper die 4; by using the micro electric telescopic rod 12, it is convenient to drive the knocking block 13 to knock the upper die 4 and the lower die 3, so as to facilitate the vibration of the upper die 4 and the lower die 3, and further facilitate the discharge of the gas in the solution in the upper die 4 and the lower die 3, improving the quality of the production of the aluminum alloy lower shell; a sponge 15 is arranged on the knocking block 13; by using the sponge 15, the flexibility of the knocking block 13 is improved, so as to facilitate the protection of the upper die 4 and the lower die 3.

[0018] In the present invention, a plurality of guide rods 8 are arranged between the workbench 1 and the top cover 7, and the mounting plate 5 is slidably arranged with respect to the guide rods 8; by using the guide rods 8, it is convenient to guide and position the upper die 4, so as to facilitate the stable movement of the upper die 4 and enable the upper die 4 to be clamped with the lower die 3.

[0019] An intelligent control component is further arranged inside the control box of the exhaust system, and the intelligent control component includes an acquisition module, an analysis module and an execution module; A force sensor is installed on the knocking block 13 to collect the data of the magnitude of the force exerted by the knocking block 13 on the lower die 3, and the telescopic speed data, load data and ambient temperature data of the micro electric telescopic rod 12 corresponding to the knocking force are respectively collected through a displacement sensor, a strain gauge and a temperature sensor; The strain gauge with corresponding specifications and sensitivity is pasted on the surface of the key stressed components (such as the rod body of the push rod, the connecting head part, etc.) of the micro electric telescopic rod 12, and the strain gauge is connected into a measuring bridge circuit by using a Wheatstone bridge circuit. The change of the strain gauge resistance will cause the change of the output voltage of the bridge. Measure the output voltage of the bridge, and the relative change amount of the strain gauge resistance and the strain The relationship between them is: , is the resistance change amount, is the initial resistance value of the strain gauge, is the sensitivity coefficient of the strain gauge; The output voltage of the bridge and the change amount of the strain gauge resistance The relationship is: , is the power supply voltage of the bridge, then the strain can be deduced; within the elastic range, the relationship between the stress and the strain , is the elastic modulus of the material of the force-bearing component of the micro electric telescopic rod 12; the cross-sectional area of the force-bearing component of the micro electric telescopic rod 12 is , the load force , and the load force is deduced .

[0020] Sort the collected tapping force data, telescopic speed data, load data, and ambient temperature data according to the collection time, and calculate the mean value of the data items corresponding to the same time, and calculate the standard deviation . Calculate the mean value and standard deviation calculated, and set the fluctuation range of the detection data with the calculated mean value and standard deviation . Mark the data items that are not within the fluctuation range among the data items corresponding to the same time as outliers, and count the number of outliers. If the preset proportional threshold is reached, it is determined that the detection data is not accurate, and the corresponding item data detected at this time point is marked as abnormal; otherwise, the outliers are removed, the mean value of the remaining detection data is calculated, and the calculated mean value is used as the corresponding item detection data at this time point. Then, a data set corresponding to the collection time is established. Each data set corresponds to a collection time, and the data set contains tapping force data, as well as the telescopic speed data, load data, and ambient temperature data corresponding to the tapping force data; Establish a relationship model of tapping force with respect to telescopic speed , load and ambient temperature : , , , , are regression coefficients; substitute the tapping force data, telescopic speed data, load data, and ambient temperature data in the data set into the relationship formula of tapping force , calculate the regression coefficients, and substitute the calculated regression coefficients into the relationship formula of tapping force . When the load and ambient temperature do not change much, obtain the relationship formula of tapping force with respect to the telescopic speed of the micro electric telescopic rod 12.

[0021] The presence of air bubbles affects the heat transfer characteristics of the casting liquid. Compared with the normal casting liquid around, the heat conduction in the area containing air bubbles becomes worse, and the temperature change is relatively slower. Temperature probes are set at multiple positions inside the mold to collect the temperature data at each position inside the mold in real time, and a two-dimensional coordinate system of temperature data and acquisition time is established. The corresponding coordinate points are plotted and connected in the coordinate system, the slope of each connected line is calculated, and the slope of the connected line is compared with a preset change threshold. It is determined that the temperature change amplitude in the corresponding connected line time period with a slope less than the preset change threshold is less than the normal value, the mold position corresponding to the temperature probe is obtained, and the corresponding connected line time period is recorded as the air bubble time period. The slope of the connected line in the adjacent time period of the air bubble time period of the temperature probe is compared with the preset change threshold. If the slope of the connected line in the adjacent time period of the air bubble time period is less than the preset change threshold, a stable count is performed. Each time a slope of the connected line in an adjacent time period is detected to be less than the preset change threshold, the stable count corresponding to the air bubble time period is incremented by one; Mark the positions of the temperature probes with a stable count greater than the preset count threshold, generate a knocking signal, and transmit the knocking signal to the execution module; The slope of the connected line for the corresponding time period is compared with the preset change threshold to calculate the specific value and compare the calculated specific value with the preset step thresholds , , , , and compare. Each preset step threshold corresponds to a knocking force. If , it is determined to adopt the corresponding knocking force.

[0022] Working principle: When the present invention is in use, the electric push rod 6 is turned on. The movable end of the electric push rod 6 extends to drive the mounting plate 5 to move downward, thereby driving the upper mold 4, so that the upper mold 4 and the lower mold 3 are closed. Then, the molten metal is injected between the upper mold 4 and the lower mold 3; Then, the micro electric telescopic rod 12 is turned on. The movable end of the micro electric telescopic rod 12 extends to drive the knocking block 13 to move, so that the knocking block 13 knocks on the lower mold 3. By the telescopic movement of the movable end of the micro electric telescopic rod 12, the lower mold 3 is knocked and vibrated, which is convenient for discharging the gas in the upper mold 4 and the lower mold 3, avoiding the appearance of air bubbles during the production of the aluminum alloy lower shell, and thus improving the quality of the aluminum alloy lower shell.

[0023] The foregoing description of the embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An aluminum alloy lower shell low-pressure casting exhaust system, comprising a workbench (1), pillars (9) arranged at the four corners of the top surface of the workbench (1), and a top cover (7) arranged on the top of the pillars (9), characterized in that: A bracket 1 (2) is provided on the top surface of the workbench (1), and a lower mold (3) is provided on the top of the bracket 1 (2); The top cover (7) is provided with an electric push rod (6), the movable end of the electric push rod (6) is provided with a mounting plate (5), and the bottom surface of the mounting plate (5) is provided with an upper mold (4) that cooperates with the lower mold (3); The top surface of the workbench (1) is also provided with an exhaust member; The exhaust system control box is also equipped with an intelligent control component, which includes an analysis module; The analysis module analyzes the relationship between the knocking force and the telescopic speed, load and ambient temperature of the micro electric telescopic rod (12), substitutes the detection data of the corresponding items to obtain the relationship between the knocking force and the telescopic speed, load and ambient temperature; analyzes the temperature data of the casting liquid inside the mold, determines the knocking position and the required knocking force, generates a knocking signal, and transmits the knocking signal to the execution module.

2. The aluminum alloy lower shell low-pressure casting exhaust system according to claim 1, characterized in that: The exhaust member comprises a second bracket (11) symmetrically arranged on the top surface of the workbench (1) and a rectangular box (10) arranged on the top surface of the second bracket (11); a micro electric telescopic rod (12) is arranged in the rectangular box (10); a knocking block (13) is arranged at the movable end of the micro electric telescopic rod (12); and a plurality of exhaust holes (14) are arranged on the top surface of the upper mold (4).

3. The aluminum alloy lower shell low pressure casting exhaust system according to claim 2, characterized in that: The knocking block (13) is provided with a sponge (15).

4. The aluminum alloy lower shell low-pressure casting exhaust system according to claim 3, characterized in that: A plurality of guide rods (8) are provided between the workbench (1) and the top cover (7), and the mounting plate (5) and the guide rods (8) are slidably arranged.

5. The aluminum alloy lower shell low pressure casting exhaust system according to claim 1, characterized in that: The intelligent control component also includes an acquisition module and an execution module; A collection module detects the knocking force of the knocking block (13), detects the telescopic speed data, load data and ambient temperature data of the micro electric telescopic rod (12) corresponding to the knocking force, detects the temperature data of the casting liquid inside the mold, and transmits the detection data to the analysis module; The execution module receives the knocking signal transmitted by the analysis module, and performs a knocking operation corresponding to the knocking force according to the transmitted knocking position data.

6. The aluminum alloy lower shell low pressure casting exhaust system according to claim 5, characterized in that: The steps for analyzing the load of the micro electric telescopic rod (12) by the analysis module are as follows: S1: Measure the output voltage of the bridge and the relative change of the strain gauge resistance With strain The relationship between: , is the resistance change, is the initial resistance value of the strain gauge, is the sensitivity coefficient of the strain gauge; S2: Bridge output voltage The change in strain gauge resistance Relationship: , is the bridge supply voltage, then the strain ; In the elastic range, the stress With strain Relationship: , is the elastic modulus of the material of the stress-bearing component of the micro electric telescopic rod (12); the cross-sectional area of ​​the stress-bearing component of the micro electric telescopic rod (12) is , load force , derive the load force .

7. The aluminum alloy lower shell low pressure casting exhaust system according to claim 6, characterized in that: The analysis steps of the knocking force relationship analysis module are as follows: N1: Sort the collected striking force data, stretching speed data, load data and ambient temperature data according to the collection time, and sort the corresponding items detected at the same time. The mean of the data and standard deviation Calculation, and the calculated mean and standard deviation Set the fluctuation range of the detection data. The fluctuation range is , the corresponding items detected at the same time The data that are not within the fluctuation range are recorded as outliers, and the number of outliers is To conduct statistics; N2: If the preset ratio threshold , then the detected data is judged to be inaccurate, and the corresponding data detected at that time point is marked as abnormal; Otherwise, the outliers are removed, the mean of the remaining detection data is calculated, and the calculated mean is used as the corresponding detection data at that time point. Then, a data set corresponding to the collection time is established. Each data set corresponds to a collection time. The data set contains the knocking force data, as well as the extension and contraction speed data, load data, and ambient temperature data corresponding to the knocking force data. N3: Establishing the percussion force About the speed of expansion ,load and ambient temperature The relationship model: , , , , is the regression coefficient; N4: Substitute the knocking force data, extension speed data, load data and ambient temperature data in the data set into the knocking force , calculate the regression coefficient, and substitute the calculated regression coefficient into the tapping force When the load and ambient temperature do not change much, the knocking force is obtained. About the telescopic speed of the micro electric telescopic rod (12) The relationship formula.

8. The aluminum alloy lower shell low pressure casting exhaust system according to claim 7, characterized in that: The steps for the analysis module to analyze the casting liquid temperature are as follows: M1: Establish a binary coordinate system of temperature data and acquisition time, draw and connect corresponding coordinate points in the coordinate system, calculate the slope of each connecting line segment, and compare the slope of the connecting line with the preset change threshold. Determine that the temperature change amplitude of the corresponding connecting line time period when the slope is less than the preset change threshold is less than the normal value, obtain the mold position corresponding to the temperature probe, and record the corresponding connecting line time period as the bubble time period; Compare the slope of the line connecting the adjacent time periods of the temperature probe bubble time period with the preset change threshold. If the slope of the line connecting the adjacent time periods of the bubble time period is less than the preset change threshold, perform a stable count. Each time a slope of the line connecting an adjacent time period is detected to be less than the preset change threshold, the stable count of the corresponding bubble time period is increased by one. M2: Mark the temperature probe position where the stable count is greater than the preset count threshold, generate a knock signal, and transmit the knock signal to the execution module; M3: The slope of the line corresponding to the time period With preset change threshold To compare, to calculate The specific value of , and the specific value calculated With preset step threshold , , , , For comparison, each preset step threshold corresponds to a tapping force. , then the decision is to use The corresponding tapping force.

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