Die-casting die for aluminum alloy connecting bracket

Abstract

The utility model relates to a die-casting die, in particular to a die-casting die of an aluminum alloy connecting support, and aims to overcome the defects of unbalanced mold filling speed, shrinkage porosity, cold shut and the like in local positions and the like in the mold filling process of an initially designed die-casting die. Optimized measures are as follows: the branch runners, close to the rib parts, of the fastening parts are in arc transition connection with the transverse runner, so that the jet flow tendency of molten metal in the branch runners when the molten metal enters a cavity is reduced, and negative-pressure air suction or air entrapment is prevented; the sectional areas of the branch pouring gate and the inner pouring gate are increased, and the mold filling speed of the rib part and the fastening part is increased; the auxiliary overflow groove is formed in the middle position, close to the flow gate, of the fastening part and used for discharging gas close to the local position of the flow gate, generation of air holes is reduced, and therefore liquid phase islands at the corners of the fastening part are prevented from being formed.

Description

Technical Field

[0001] This utility model relates to the field of die-casting molds, specifically to a die-casting mold for an aluminum alloy connecting bracket. Background Technology

[0002] In the manufacturing process of new energy vehicles, it is often necessary to connect the vehicle's electric motor with other power components to improve system efficiency and achieve complex functions. This aluminum alloy connecting bracket part, used for assembling the electric motor with other power components in new energy vehicles, is made of A356.2 aluminum alloy and mass-produced using cold chamber high-pressure casting. This material has advantages such as good fluidity, low specific gravity, and good corrosion resistance. It also exhibits excellent properties such as no tendency for hot cracking during die casting, low linear shrinkage, and good airtightness. The connecting bracket weighs 2.75 kg, has a volume of 1013.38 cm³, an average wall thickness of 3.5 mm, and overall dimensions of 319 mm × 209 mm. The die-casting mold material for the connecting bracket part is SKA61 grade. To enable the connection between the electric motor of new energy vehicles and various power components of different shapes, the inner surface structure of the connecting bracket is designed with many uneven frames and thin-walled connecting ribs. This uneven frame and rib structure causes uneven filling speed and flow rate in different parts during aluminum alloy die casting, which can easily lead to defects such as porosity, cold shuts, and material shortages in parts, especially in areas requiring machining. The initial gating system design uses multiple sprues and ingates with equal cross-sectional areas to pour into the casting cavity, and each sprue intersects the runner perpendicularly. Multiple overflow channels are also set to stabilize the flow of molten metal and to contain impurities and improve venting.

[0003] MAGMASOFT software was used to simulate the temperature changes, filling speed, gas pressure changes, and shrinkage defects during the die casting process of the bracket. The simulation showed that the filling speed was uneven and the filling completion time was asynchronous. In the early stage of filling, the heat conduction speed between the aluminum liquid and the mold was asynchronous, and the temperature change rate was different. The gas pressure value was higher at the intersection of the fastening cavity and the rib cavity, and a small amount of aluminum liquid was trapped at the ingate. Liquid islands formed hot spots at the four corners of the fastening part, which will result in shrinkage defects after solidification, and will affect the connection between the motor and other power components after molding. Utility Model Content

[0004] The present invention aims to solve the above-mentioned technical problems, optimize and balance the filling flow and speed, so that the filling of the rib cavity, the fastening cavity and the frame cavity is completed simultaneously, and reduce the difference in the rate of temperature change.

[0005] The technical solution adopted by this utility model is a die-casting mold for an aluminum alloy connecting bracket, including an upper mold, a lower mold, a mold closing mechanism, a gating system, and an overflow system. The mold closing mechanism allows the upper mold to separate and engage with the lower mold, forming a casting cavity when the upper and lower molds are engaged. The casting cavity includes a rib section cavity, a fastening section cavity, and a frame section cavity, with the frame section cavity being more complex than the fastening section cavity, which is more complex than the rib section cavity. The gating system includes a sprue, a runner, a gating system, and an ingate. One end of the sprue is connected to the gate, and the other end is connected to the runner. Multiple gating systems are vertically connected to the runner, each of which... All runners are connected to the casting cavity through corresponding ingates; the number of runners connected to the frame cavity is greater than the number of runners connected to the fastening cavity, and the number of runners connected to the fastening cavity is greater than the number of runners connected to the rib cavity; the overflow system includes multiple overflow channels, which are connected to the casting cavity respectively; the number of overflow channels connected to the fastening cavity is greater than the number of overflow channels connected to the frame cavity, and the number of overflow channels connected to the frame cavity is greater than the number of overflow channels connected to the rib cavity; the cross-sectional area of ​​the ingate of the fastening cavity near the rib cavity is greater than the cross-sectional area of ​​the ingate of the rib cavity.

[0006] Increasing the cross-sectional area of ​​the ingate near the rib section cavity in the fastening section cavity increases the filling flow rate of both the rib and fastening sections, accelerating the filling speed and balancing it with the frame section cavity. This prevents uneven filling speeds, which can lead to defects such as condensation, laminar flow, and flow lines caused by the mixing of molten aluminum at different speeds and temperatures. In the initial design, the small cross-sectional area of ​​this ingate resulted in increased flow velocity and air pressure, leading to insufficient heat exchange between the molten aluminum and the mold, causing asynchronous heat transfer. Therefore, increasing the cross-sectional area of ​​this ingate reduces the flow velocity and air pressure, allowing for more efficient heat exchange between the molten aluminum and the mold.

[0007] Furthermore, the gating system is inclined between the sprue and the runner in the cavity of the fastening section near the cavity of the rib section.

[0008] Changing the angle between the sprue and the runner affects the flow velocity and pressure distribution of molten aluminum in the runner. Increasing the angle can control the flow velocity of the molten aluminum to some extent, reducing the tendency for it to spray when entering the mold cavity and avoiding problems such as turbulence and porosity caused by excessive velocity. It also helps maintain appropriate static pressure, ensuring the molten metal fills the mold cavity smoothly. The inclined feed sprue also prevents negative pressure suction or air entrapment.

[0009] Furthermore, an auxiliary overflow groove is provided in the middle position of the fastening part near the inner gate.

[0010] Because the fastener has a thicker wall, hot spots are easily formed in areas with uneven wall thickness. Simultaneously, the system cannot effectively compensate for shrinkage, leading to reduced density in the localized crystalline structure and resulting in shrinkage defects and cavities during solidification. Adding an auxiliary overflow groove in the middle of the fastener near the ingate can expel gas from the vicinity of the ingate, reducing porosity and helping to solve the problem of liquid phase islands forming at the corners of the fastener.

[0011] Furthermore, the inclination angle between the gating system and the runner of the fastening cavity near the rib cavity is 110° to 165°.

[0012] The purpose of setting the sprue at an angle intersecting the runner is to control the flow velocity of the molten aluminum, reduce the tendency of the molten aluminum to spray when entering the mold cavity, avoid problems such as turbulence and porosity caused by excessive velocity, and prevent negative pressure suction or air entrapment. If the inclination angle is less than 110°, it will not achieve the above effects. If the inclination angle is greater than 165°, the molten metal may encounter more resistance during flow, thereby reducing fluidity and affecting the smooth filling of the mold cavity, which may lead to defects such as incomplete filling or cold shuts in the casting. In addition, an excessively large inclination angle may affect the flow state of the molten metal in the runner, thereby affecting the temperature distribution, resulting in inconsistent cooling rates in different parts of the casting, stress concentration, and even crack formation.

[0013] Furthermore, the ingate is a flat, flared shape.

[0014] The flat, flared inlet design can reduce temperature differences to some extent, which is beneficial in preventing cracks near the inlet. Furthermore, the flat, flared inlet shape helps reduce fluid turbulence and improves filling consistency, which is crucial for ensuring casting quality.

[0015] Furthermore, the number of sprues connected to the rib section is 1 to 2, the number of sprues connected to the fastening section is 2 to 4, and the number of sprues connected to the frame section is 3 to 5.

[0016] Because the frame section of the target casting is more complex than the fastening section, and the fastening section is more complex than the rib section, the frame section has the most connected runners, followed by the fastening section, and the rib section has the fewest. Based on parameters such as cavity filling time, ingate cross-sectional area, and filling pressure, the number of runners connected to the rib section is set to 1-2, the number of runners connected to the fastening section is 2-4, and the number of runners connected to the frame section is 3-5. This ensures that the filling speed of the rib section, fastening section, and frame section is balanced and the filling completion time is synchronized.

[0017] Furthermore, the number of overflow grooves connected to the rib section is 1 to 2, the number of overflow grooves connected to the fastening section is 4 to 6, and the number of overflow grooves connected to the frame section is 3 to 5.

[0018] The rib section consists of thin-walled frame connecting ribs, requiring a smaller flow rate of molten aluminum; 1-2 overflow grooves are sufficient. The frame section has a more complex structure, but its wall thickness is more uniform; therefore, 3-5 overflow grooves are provided. The fastening section, while less complex than the frame section, has uneven wall thickness, with a thicker section connecting to the rib and frame sections. This makes it prone to shrinkage cavities and defects during solidification. Furthermore, the fastening section requires machining after die casting, demanding high dimensional accuracy and internal density. Therefore, 4-6 overflow grooves are provided in the fastening section to stabilize the flow of molten metal, accommodate impurities, and improve venting, thereby enhancing the die casting quality of this section.

[0019] Furthermore, the rib section cavity has a thin-walled section, and an overflow groove is connected to the thin-walled section.

[0020] Due to the narrow cavity in thin-walled areas, "dead corner air trapping" may occur during filling. Therefore, an overflow channel is installed in this area to avoid this situation.

[0021] Furthermore, the overflow channel includes a main body, a connecting part, and an exhaust channel. The connecting part connects the main body to the casting cavity, and one end of the exhaust channel is connected to the main body, while the other end passes through the upper mold.

[0022] The molten metal that is injected into the mold cavity and the gas entrained during the filling process enter the main body of the overflow tank through the connecting part, ensuring the flow of the molten aluminum and guaranteeing that the molten metal can smoothly fill the mold cavity. The main body contains the molten metal that has been condensed, while the gas is discharged from the mold through the exhaust channel.

[0023] Furthermore, the rib section cavity is a thin-walled frame connecting rib, the fastening section cavity has a thicker wall, the frame section cavity has a more uniform wall thickness, and the thickness of the rib section cavity and the fastening section cavity is greater than the thickness of the frame section cavity.

[0024] The structural characteristics of the casting cavity have a crucial impact on mold design. The thin-walled structure of the rib section cavity results in insufficient aluminum flow during filling, easily leading to defects such as jetting, air entrapment, and cold shuts. Balancing the filling pressure and properly designing overflow channels are necessary. The thicker walls of the fastening section cavity hinder heat dissipation and prevent effective shrinkage compensation, potentially causing reduced density in localized crystallization and shrinkage defects and cavities during solidification. Therefore, adjusting the filling speed and pressure is required to achieve more uniform pouring and reduce the formation of liquid phase islands, or adding a venting system to reduce porosity and prevent liquid phase island formation. The frame section cavity has a more uniform wall thickness, less than that of the fastening and rib sections, resulting in faster solidification. However, due to differences in filling flow and speed, defects such as porosity, cold shuts, and deformation are prone to occur at the junction of the aluminum flow in the frame and solid sections, affecting dimensional accuracy and ultimately impacting the connection and installation functionality. Therefore, it is necessary to balance the filling speed and pressure of the frame cavity, the fastening cavity, and the rib cavity.

[0025] Compared with existing technologies, the beneficial effects of this invention are as follows: By increasing the cross-sectional area of ​​the ingate near the rib cavity of the fastening part, the filling flow rate of both the rib cavity and the fastening part cavity is increased, accelerating the filling speed and achieving a balance between the filling of the fastening part cavity and the frame cavity. This reduces defects such as condensation, laminar flow, and flow lines caused by the convergence of aluminum liquids at different speeds and temperatures due to uneven filling speeds. Simultaneously, increasing the cross-sectional area of ​​the ingate reduces its flow rate and air pressure, allowing for sufficient heat exchange between the aluminum liquid and the mold. This solves problems such as asynchronous heat transfer speeds between the aluminum liquid and the mold, differences in temperature change rates, and uneven temperature gradient distribution in different areas during the filling process. Accelerating the filling speed of the ingate also allows the aluminum liquid to fill the cavity evenly, reducing the generation of porosity and defects in the fastening part, and also helps prevent the formation of liquid phase islands in the fastening part cavity. The sprue near the rib section cavity of the fastening section was modified into an inclined inlet design, reducing the tendency of molten metal to spray when entering the cavity from the ingate. The stroke was lengthened, and the inclined inlet design also prevents negative pressure suction or air entrapment. An auxiliary overflow groove was placed in the middle of the fastening section cavity near the ingate to reduce the formation of pores at the corners of the fastening section, thus preventing the formation of liquid phase islands in that area. Attached Figure Description

[0026] Figure 1 This is a 3D view of the aluminum alloy connecting bracket.

[0027] Figure 2(a) is a schematic diagram of the initial design cavity, gating system and overflow system.

[0028] Figure 2(b) is a schematic diagram of the initial cavity design.

[0029] Figure 2(c) is a schematic diagram of the initial design of the connecting support casting system.

[0030] Figure 3(a) is a simulation diagram of 20% aluminum liquid filling.

[0031] Figure 3(b) is a simulation diagram of 60% aluminum liquid filling.

[0032] Figure 3(c) is a simulation diagram of 85% aluminum liquid filling.

[0033] Figure 3(d) shows a simulation diagram of 95% aluminum liquid filling.

[0034] Figure 4(a) is a simulation diagram of air pressure changes and air entrapment defects during the filling process.

[0035] Figure 4(b) is a simulation diagram of the prediction of thermal shrinkage defects.

[0036] Figure 5 This is a 3D view of the upper mold.

[0037] Figure 6 This is a three-dimensional view of the lower mold.

[0038] Figure 7 This is a schematic diagram showing the connection between the optimized cavity and the gating and overflow systems.

[0039] Figure 8 This is a schematic diagram of the optimized cavity structure.

[0040] Figure 9 A schematic diagram of the optimized post-casting system.

[0041] Figure 10 PQ generated by simulation after modifying the cross-sectional area of ​​the second ingate 2 Relationship curve.

[0042] Figure 11(a) shows the simulated gas pressure at the junction of the molten metal before optimization.

[0043] Figure 11(b) shows the simulated gas pressure at the junction of the optimized molten metal.

[0044] Figure 12 This is a simulation diagram of the temperature changes of the molten metal and the mold during the filling process. Detailed Implementation

[0045] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this invention. To better illustrate the following embodiments, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0046] like Figure 1As shown, the target casting is an aluminum alloy connecting bracket 1, including a rib section 11, a fastening section 12, and a frame section 13. The rib section 11 is a thin-walled frame connecting rib. During die casting, the metal flow rate is relatively low, which easily leads to defects such as jetting, air entrapment, and cold shut. It is necessary to balance the filling pressure and properly set the overflow groove. The fastening section 12 is a connecting and fastening assembly part that connects to other parts. After die casting, it needs to be machined. Therefore, the dimensional accuracy and internal density requirements of this part are high, and the internal structure of the casting must be dense and free of pores. The frame section 13 has a relatively uniform wall thickness and is easy to solidify quickly. However, due to the difference in filling flow rate and speed, defects such as pores, cold shuts, and deformation are prone to occur at the local position where it intersects with the fastening section. The thickness of the rib section 11 and the fastening section 12 is greater than the thickness of the frame section 13.

[0047] Based on the structural characteristics and quality requirements of the target casting, and according to the parameters of the selected die-casting machine such as pressure, speed and barrel diameter, a preliminary gating system, overflow system and mold preheating temperature were designed. The process parameters are shown in Table 1.

[0048] Table 1 Initial parameters for numerical simulation of low-pressure casting of support frame

[0049] Parameter name numerical values Parameter name numerical values Die casting machine tonnage 800t Cavity filling time 0.032s Casting pressure 650 bar gate speed 56m / s Injection stroke 530mm initial temperature of mold 185° Minimum speed of punch 0.2m / s Adjustment range of ingate cross-sectional area <![CDATA[2.0cm 2 -5.5cm 2 ]]> Punch top speed 3.5m / s Aluminum liquid temperature 660° punch diameter 50mm Maximum filling pressure 63.5 MPa

[0050] Based on the fundamental principle that the molten metal should fill the mold cavity with the shortest possible flow path at the ingate location to prevent excessive heat loss during filling and thus die-casting defects such as cold shuts or patterns, the initial ingate design employed multiple short runners for simultaneous feeding, as shown in Figure 2(a). Each runner had a similar cross-sectional shape and size to ensure even and stable filling of the molten metal, facilitating venting and static pressure transmission. Furthermore, considering the flat and dispersed shape of the connecting bracket, the differentiated structures of the rib section, fastening section, and frame section could potentially hinder the even filling of the molten aluminum. During filling, collisions at the confluence of several molten metal flows could generate eddies and air entrapment. Additionally, uneven wall thickness leading to differences in solidification timing could cause die-casting defects such as cold shuts and deformation. Therefore, multiple overflow channels were designed to stabilize the flow of the molten metal and to accommodate impurities and improve venting. Specifically, for the thin-walled frame of the rib section, an overflow channel was specifically designed to avoid "dead-angle air trapping" caused by poor filling in this area.

[0051] As shown in Figures 2(a), 2(b) and 2(c), a die-casting mold for an aluminum alloy connecting bracket includes an upper mold 6, a lower mold 7, a mold closing mechanism, a gating system 3 and an overflow system 4. The mold closing mechanism enables the upper mold 6 to engage and disengage relative to the lower mold 7. When the upper mold 6 and the lower mold 7 are engaged, the upper mold 6 and the lower mold 7 can form a casting cavity 2.

[0052] The casting cavity 2 includes a rib cavity 21, a fastening cavity 22, and a frame cavity 23.

[0053] The gating system 3 includes a sprue 31, a runner 32, a gating system 33, and an ingate 34. One end of the sprue 31 is connected to the main gate, and the other end is connected to a first runner 321 and a second runner 322. The first runner 321 and the second runner 322 are located on opposite sides of the sprue 31. The first runner 321 is sequentially connected to a first gating system 331, a second gating system 332a, and a third gating system 333. The second runner 322 is sequentially connected to a fourth gating system 334, a fifth gating system 335, and a sixth gating system 336. The first gating system 331, the second gating system 332a, the third gating system 333, the fourth gating system 334, the fifth gating system 335, and the sixth gating system 336 intersect the first runner 321 and the second runner 322 perpendicularly. Furthermore, the cross-sectional shapes and dimensions of the first runner 331, the second runner 332a, the third runner 333, the fourth runner 334, the fifth runner 335, and the sixth runner are similar. The first runner 331 is connected to the rib cavity 21 through the first ingate 341. The second runner 332a and the third runner 333 are connected to the fastening cavity 22 through the second ingate 342a and the third ingate 343, respectively. The fourth runner 334, the fifth runner 335, and the sixth runner 336 are connected to the frame cavity 23 through the fourth ingate 344, the fifth ingate 345, and the sixth ingate 346, respectively. The cross-sectional area of ​​the first ingate 341, the second ingate 342a, and the sixth ingate 343 is 2.25 cm². 2 The cross-sectional area of ​​the third ingate 343, the fourth ingate 344, and the fifth ingate 345 is 3.35 cm². 2 .

[0054] The overflow system includes multiple overflow channels 4, which are connected to the casting cavity 2 respectively. Among them, there is one overflow channel 4 connected to the rib cavity 21, which is located at the thin wall position of the rib cavity 21. There are four overflow channels 4 connected to the fastening cavity 22 and three overflow channels 4 connected to the frame cavity 23.

[0055] Based on the die-casting structural characteristics and quality requirements of the connecting bracket parts, MAGMASOFT software was used to simulate four aspects of the die-casting filling process: temperature change, filling speed, air pressure change, and shrinkage defect prediction.

[0056] like Figure 3(a) , 3(b)Figures 3(c) and 3(d) show the simulations of different stages of aluminum liquid filling. The simulation comparison reveals an imbalance in the filling speed and cooling / solidification sequence of different process areas during the solidification process of the support casting. The temperature change simulation results show that in the initial aluminum liquid filling stage (Figure 3(a)), the heat conduction speed between the aluminum liquid and the mold is asynchronous, resulting in differences in temperature change rates. As shown in Figure 3(b), the filling completion times of the rib section cavity, the fastening section cavity, and the frame section cavity are asynchronous. When the frame section cavity, which is the first to be filled, is almost completely filled, nearly one-fifth of the rib section cavity and the fastening section cavity are still not filled. The simulation results in Figures 3(c) and 3(d) show that air trapping occurs near the rib section cavity in the fastening section cavity. Simultaneously, the temperature gradient distribution in different areas during the filling process is highly uneven, easily leading to shrinkage porosity, shrinkage cavities, and cold shut defects. This may be because the uneven filling speed causes the aluminum liquid in different areas to cool at different rates, resulting in different temperature gradients.

[0057] For the situation shown in Figure 3(a), the flow rate of molten aluminum in the sprue and gate can be reduced by increasing the cross-sectional area of ​​the ingate and the angle between the sprue and runner, thus allowing for sufficient heat exchange between the molten aluminum and the mold. For the situations shown in Figures 3(b), 3(c), and 3(d), it is also necessary to increase the cross-sectional area of ​​the ingate at the corresponding location, and increase the filling flow rate and filling speed to balance the filling flow rate and speed of the rib cavity, fastening cavity, and frame cavity. Regarding the uneven temperature gradient distribution in different areas during the filling process, the cross-sectional area of ​​the ingate at the corresponding location can be increased, and the filling speed at the corresponding location can be adjusted to ensure that the molten aluminum in each part of the casting cavity fills the mold evenly, thereby reducing the formation of temperature gradients.

[0058] As shown in Figure 4(a), the air pressure simulation shows that the air pressure value is higher at the intersection of the rib section and the fastener section. There is air entrapment in the machining area of ​​the fastener section, and there is a possibility of internal pores appearing after machining. At the same time, there is also a small amount of aluminum liquid entrapment at the ingate position.

[0059] The reason for this is the uneven feed flow rate and speed of the six guillotines. When molten aluminum from different guillotines converges at the final filling position of the casting with different speeds and temperatures, defects such as vacuuming, laminar flow, and flow lines are easily formed at the metal confluence. This can be addressed by increasing the cross-sectional area of ​​the guillotines at the corresponding positions, increasing the filling flow rate and speed, thus balancing the filling flow rate and speed of the rib section cavity, the fastening section cavity, and the frame section cavity, and reducing the speed and temperature differences at the aluminum confluence.

[0060] The defect prediction simulation in Figure 4(b) shows that liquid phase islands form hot spots at the four corners of the fastener, which will result in shrinkage cavities after solidification. This is because the fastener wall is relatively thick, especially at the four corners, making heat dissipation difficult and causing these areas to be the last to solidify. In this case, the surrounding metal has already solidified, forming a relatively enclosed space, preventing effective feeding of this molten metal and thus creating liquid phase islands. The formation of liquid phase islands can be reduced by adjusting the pouring speed and pressure to achieve more uniform pouring, or by adding a ventilation system to reduce porosity.

[0061] Based on the simulation results and analysis above, the root cause of the aforementioned defects is the uneven filling flow rate and velocity of the rib section, fastening section, and frame section cavities. The aluminum liquid entering the cavity earlier has a different temperature and velocity than the later-entering liquid, and when they converge, defects such as vacuuming, laminar flow, and flow lines are formed. Therefore, the gating and overflow systems should be modified to balance the relationship between the filling flow rate and filling pressure in different parts of the casting, ensuring a uniform filling velocity and synchronized solidification and cooling times for the rib section, fastening section, and frame section. Simultaneously, an additional venting system can be added to reduce porosity and prevent hot spots from forming at the corners of the fastening section.

[0062] Therefore, this utility model provides a die-casting mold for an aluminum alloy connecting bracket, including an upper mold 6, a lower mold 7, a mold closing mechanism, a gating system 3 and an overflow system 4. The mold closing mechanism enables the upper mold 6 to engage and disengage relative to the lower mold 7. When the upper mold 6 and the lower mold 7 engage, the upper mold 6 and the lower mold 7 can form a casting cavity 2.

[0063] The casting cavity 2 includes a rib cavity 21, a fastening cavity 22, and a frame cavity 23.

[0064] The gating system 3 includes a sprue 31, a runner 32, a gating system 33, and an ingate 34. One end of the sprue 31 is connected to the main gate, and the other end is connected to a first runner 321 and a second runner 322. The first runner 321 and the second runner 322 are located on both sides of the sprue 31. The first runner 321 is sequentially connected to a first gating system 331, a second gating system 332a, and a third gating system 333. The second runner 322 is sequentially connected to a fourth gating system 334, a fifth gating system 335, and a sixth gating system 336. The first gating system 331, the third gating system 333, the fourth gating system 334, the fifth gating system 335, and the sixth gating system 336 intersect the first horizontal gating system 321 and the second horizontal gating system 322 perpendicularly, respectively. The second gating system 332 intersects the first horizontal gating system 321 at an angle of 110° to 165°. Furthermore, the cross-sectional areas of the first gating system 331, the second gating system 332, the third gating system 333, the fourth gating system 334, the fifth gating system 335, and the sixth gating system 336 are equal. The first gating system 331 is connected to the rib section cavity 21 via the first ingate 341. The second gating system 332 and the third gating system 333 are connected to the fastening section cavity 22 via the second ingate 342 and the third ingate 343, respectively. The fourth gating system 334, the fifth gating system 335, and the sixth gating system 336 are connected to the frame section cavity 23 via the fourth ingate 344, the fifth ingate 345, and the sixth ingate 346, respectively. The cross-sectional area of ​​the second ingate 342, the third ingate 343, the fourth ingate 344, and the fifth ingate 345 is 3.35 cm². 2 The cross-sectional area of ​​both the first guillotine 341 and the sixth guillotine 346 is 2.25 cm². 2 .

[0065] The overflow system includes multiple overflow channels 4, which are connected to the casting cavity 2 respectively. There is one overflow channel 4 connected to the rib cavity 21, which is located at the thin wall position of the rib cavity 21. There are four overflow channels 4 connected to the fastening cavity 22. An auxiliary overflow channel 5 is also provided between the second ingate 342 and the third ingate 343. There are three overflow channels 4 connected to the frame cavity 23.

[0066] like Figure 5 The overflow channel 4 shown includes a connecting part 41, a main body part 42 and an exhaust channel 43. The connecting part 41 connects the main body part 42 to the casting cavity 2. One end of the exhaust channel 43 is connected to the main body part 43, and the other end leads to the outside of the mold.

[0067] During die casting, molten aluminum is injected through the gate and enters the mold cavity sequentially through the sprue, runner, gating system, and ingate. The molten aluminum that enters earlier, along with the gas and impurities in the mold cavity, enters the main body through the overflow channel to stabilize the flow of the molten aluminum. The main body then contains the molten aluminum and impurities, while the venting channel discharges the gas from the mold.

[0068] MAGMASOFT software generates PQ based on the equipment and ingate design scheme. 2 The relationship curve helps designers verify the ideal process range between filling pressure and flow rate, thereby verifying and judging the rationality of the ingate area design. By inputting different ingate design parameters into the software, the software automatically calculates the corresponding PQ (Power Quotient). 2 Relationship curve, check PQ 2 Check the process adaptation window to see if it falls within the optimal process parameter combination range in the gray area.

[0069] like Figure 10 As shown, input the optimized cross-sectional area of ​​the second ingate, and simulate the generated PQ. 2 The process curves are within the optimal region, proving the feasibility of the optimization scheme of changing the cross-sectional area of ​​the second ingate. Meanwhile, according to PQ... 2 The relationship curves show that parameters such as the maximum filling pressure, cavity filling time, and initial mold temperature of the initial process were adjusted and optimized accordingly. The specific parameter improvements are shown in Table 2.

[0070] Table 2 Comparison of Initial Process and Optimized Scheme Parameters

[0071]

[0072]

[0073] To verify whether each region of the casting achieved balanced filling pressure and flow rate, the optimized design was simulated again using MAGMASOFT software. Simultaneously, simulation analysis of the filling process pressure and solidification temperature was performed on the optimized design, yielding simulation curves comparing the pressure and temperature changes from the liquid to the solid phase during the die-casting process of the optimized part.

[0074] like Figure 11(a) , 11(b) As shown in the figure, the gas pressure simulation comparison at the end of the aluminum liquid filling mold before and after optimization shows that the initial design gas pressure value is high, reaching 3567 Mbar, while the optimized gas pressure value is reduced to 2302 Mbar; this indicates that the risk of gas entrapment at this metal liquid filling point is greatly reduced.

[0075] By selecting and placing simulated sensors at locations where shrinkage porosity might occur during prediction, MAGMASOFT software can also generate heat exchange and temperature change curves between the molten metal and the mold at key locations, allowing for the checking of the smoothness of the temperature curve during solidification. For example... Figure 8 As shown, the optimized temperature curve of heat conduction between the local mold and the molten metal in the casting shows a gradual decrease, proving that the casting has a reasonable cooling and solidification rate during the process from liquid phase to solid phase; thus avoiding defects such as shrinkage porosity caused by excessive temperature gradient between the casting and the mold.

[0076] The optimized simulation results show that the optimized technical solution reduces the air pressure at the end of the aluminum liquid filling process, thus avoiding defects such as shrinkage porosity caused by excessive temperature gradient between the casting and the mold.

[0077] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the technical solution of this utility model, and are not intended to limit the specific implementation of this utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the claims of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A die-casting mold for an aluminum alloy connecting bracket, comprising an upper mold, a lower mold, a mold closing mechanism, a gating system, and an overflow system, wherein the mold closing mechanism enables the upper mold to separate and engage with the lower mold, and the upper mold and the lower mold engage to form a casting cavity; The casting cavity includes the rib section cavity, the fastening section cavity, and the frame section cavity, with the frame section cavity being more complex than the fastening section cavity, which is more complex than the rib section cavity. The gating system includes a sprue, runner, sub-sprues, and gantry. One end of the sprue connects to the gate, and the other end connects to the runner. Multiple sub-sprues are vertically connected to the runner, and each sub-sprue is connected to the casting cavity via a corresponding gantry. The number of sprues connected to the cavity of the frame section is greater than the number of sprues connected to the cavity of the fastening section, and the number of sprues connected to the cavity of the fastening section is greater than the number of sprues connected to the cavity of the rib section. The overflow system includes multiple overflow channels, which are connected to the casting cavity respectively; the number of overflow channels connected to the fastening part cavity is greater than the number of overflow channels connected to the frame part cavity, and the number of overflow channels connected to the frame part cavity is greater than the number of overflow channels connected to the rib part cavity. Its features are, The cross-sectional area of ​​the ingate of the fastening part cavity, which is closer to the rib part cavity, is larger than the cross-sectional area of ​​the ingate of the rib part cavity.

2. The die-casting mold for the aluminum alloy connecting bracket according to claim 1, characterized in that, An inclined connection is provided between the gating system and the horizontal gating system located near the rib section cavity in the fastening section cavity.

3. The die-casting mold for the aluminum alloy connecting bracket according to claim 1, characterized in that, An auxiliary overflow groove is provided in the middle position of the cavity near the ingate of the fastening part.

4. The die-casting mold for the aluminum alloy connecting bracket according to claim 2, characterized in that, The inclination angle between the gating runner and the horizontal runner of the fastening cavity near the rib cavity is 110° to 165°.

5. The die-casting mold for the aluminum alloy connecting bracket according to claim 1, characterized in that, The ingate is a flat, flared shape.

6. The die-casting mold for the aluminum alloy connecting bracket according to claim 1, characterized in that, The number of sprues connected to the cavity of the rib section is 1 to 2, the number of sprues connected to the cavity of the fastening section is 2 to 4, and the number of sprues connected to the cavity of the frame section is 3 to 5.

7. The die-casting mold for the aluminum alloy connecting bracket according to claim 1, characterized in that, The number of overflow grooves in the cavity connection of the rib section is 1 to 2, the number of overflow grooves in the cavity connection of the fastening section is 4 to 6, and the number of overflow grooves in the cavity connection of the frame section is 3 to 5.

8. The die-casting mold for the aluminum alloy connecting bracket according to claim 1, characterized in that, The cavity of the rib section has a thin-walled section, and an overflow groove is connected to the thin-walled section.

9. The die-casting mold for the aluminum alloy connecting bracket according to claim 1, characterized in that, The overflow channel includes a main body, a connecting part, and an exhaust channel. The connecting part connects the main body to the casting cavity, and one end of the exhaust channel is connected to the main body, while the other end passes through the upper mold.

10. The die-casting mold for the aluminum alloy connecting bracket according to claim 1, characterized in that, The rib section cavity is a thin-walled frame connecting rib, the fastening section cavity has a thicker wall, the frame section cavity has a more uniform wall thickness, and the thickness of the rib section cavity and the fastening section cavity is greater than the thickness of the frame section cavity.

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