Integrated lower vehicle body double-injection die-casting process

Abstract

The invention relates to the technical field of high-pressure die-casting production of lower car bodies, in particular to an integrated double-injection die-casting process for a lower car body, which is characterized in that two injection systems are matched with a die-casting module with a double-pouring system to realize rapid forming production of the lower car body; through implementation of the die-casting process, integrated forming of the lower car body can be achieved at a time, and the production efficiency of the lower car body is greatly improved. Meanwhile, the die-casting machine is provided with two sets of independent injection systems which are matched with the double-injection-position pouring and discharging system at the same time; symmetrical filling can be formed for filling of the integrated lower vehicle body; the pouring efficiency of the lower car body can be guaranteed, meanwhile, molten aluminum is injected into the two pouring systems to be subjected to hedging, and the mixing uniformity of the molten aluminum can be guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of high pressure die casting production of lower vehicle bodies, and in particular discloses a double-shot die casting process for an integrated lower vehicle body. Background Art

[0002] High vacuum die casting refers to a casting method in which molten metal alloy is poured into a pressure chamber under a high vacuum condition in the mold cavity, filling the steel mold cavity at high speed and solidifying rapidly to form a casting.

[0003] Among them, die-casting machines, die-casting alloys and die-casting molds are the three major elements of production, and none of them can be missing. The so-called die-casting process is to organically and rationally utilize these three elements to stably, rhythmically and efficiently produce high-quality castings with good appearance, good internal quality, and dimensional performance that meet the specified requirements.

[0004] Currently, a single injection system is used in vehicle OEMs or die-casting plants to produce castings, such as the patent: 201922355320.X - A mold pouring system for die-casting automotive parts.

[0005] As the requirements for vehicle body integration become higher and higher, the projected area of ​​parts is also getting larger and larger. Limited by the existing die-casting process, the single-shot system cannot meet the production of large castings, and the performance of the remote area of ​​the casting cannot meet practical requirements.

[0006] Therefore, in order to solve or improve at least one of the above problems, it is necessary to optimize the design of the existing die-casting equipment or process. Summary of the invention

[0007] The object of the present invention is to provide a double-shot die-casting process capable of improving the production efficiency of a lower vehicle body.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] A one-piece lower body double-shot die-casting process comprises the following steps:

[0010] Step 1: Select a die-casting mold; the die-casting mold has a gating system;

[0011] The pouring system comprises a pouring cavity; a pouring system connected to the pouring cavity is symmetrically distributed on both sides of the pouring cavity;

[0012] The pouring system includes an external gate, a runner and an internal gate; the external gate is connected to the internal gate through the runner; the internal gate is connected to the pouring cavity;

[0013] Step 2: Inspect the die casting machine;

[0014] Step 3: Spray an isolation layer in the die casting mold cavity;

[0015] Step 4: The pouring liquid enters the corresponding barrel of the die-casting machine; the die-casting machine includes two independent injection systems; the pouring liquid is injected by the injection system into the pouring system;

[0016] Step 5: Die-casting mold closing: After the casting liquid fills the die-casting mold cavity, the die-casting machine is used to die-cast the parts into one piece. The parts are cooled and taken out by the picking robot. The production of one part is completed. If new parts need to be produced, the next cycle can be started.

[0017] In the step 4, the pouring liquid is kept warm in a heat preservation furnace before entering the die casting mold; each pouring system is connected to a heat preservation furnace.

[0018] The weight difference of the pouring liquid in the two holding furnaces is not higher than 1%; the temperature difference of the pouring liquid in the two holding furnaces is not higher than 3°C.

[0019] In step 3, the isolation layer is sprayed on the mold by pulse micro-spraying.

[0020] In step 4, the two injection systems are required to inject the casting liquid in the corresponding barrels synchronously.

[0021] The ingates all include multiple single ingates; each single ingate in each ingate is distributed in sequence on the side of the lower body along the X-axis direction of the lower body; the ingate is a trailing ingate.

[0022] The runner includes a main runner and two branch runners; the main runner is connected to the corresponding inner gate through the two branch runners.

[0023] The cross-sectional area of ​​the runner gradually decreases from the outer gate to the corresponding inner gate.

[0024] The middle area of ​​the pouring cavity forms a confluence area;

[0025] In the pouring system, the liquid flowing into the pouring system is offset in the confluence area.

[0026] The pouring system also includes a slag bag arranged in the middle area of ​​the pouring cavity; the total volume of the slag bag is V1; the volume of the confluence area is V2; and V1 is required to be not less than V2.

[0027] The liquid inlet speed of the monomer ingates connected to the same area of ​​the lower body is the same.

[0028] The pouring system is arranged in the longitudinal direction, and the pouring system in the pouring system is pre-filled with liquid through the wheel housing of the lower vehicle body.

[0029] The advantages of the present invention are:

[0030] The invention discloses a double-injection die-casting process for an integrated lower vehicle body.

[0031] The present invention is mainly a high-pressure die-casting process through the double-shot die-casting process of the one-piece lower body.

[0032] The present invention can realize the one-piece molding of the lower body at one time through the implementation of the above-mentioned die-casting process, which greatly speeds up the production efficiency of the lower body.

[0033] At the same time, the die-casting machine of the present invention has two independent injection systems and cooperates with the double-injection position pouring system at the same time; it can form symmetrical filling for the filling of the integrated lower body; it can not only ensure the pouring efficiency of the lower body, but also the two pouring systems inject aluminum liquid through hedging, which can also ensure the uniformity of aluminum liquid mixing.

[0034] At the same time, the liquid enters through the wheel arch of the lower body; thus greatly reducing the risk of cracking at the SPR connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The following is a brief description of the contents expressed in the drawings of the present invention and the symbols in the drawings:

[0036] Figure 1 It is a process flow chart of the present invention.

[0037] Figure 2 It is a schematic diagram of the structure in which the barrel of the present invention is connected to the double-pressure injection fixed template.

[0038] Figure 3 It is a schematic diagram of the structure in which the die-casting mold is connected to the injection molding machine in the present invention.

[0039] Figure 4 It is a double-shot die casting curve diagram in the present invention.

[0040] Figure 5 It is a schematic structural diagram of the die casting machine in the present invention when it is connected to a holding furnace.

[0041] Figure 6 It is the first axonometric view of the pouring system in the present invention.

[0042] Figure 7 This is the second axonometric view of the pouring system of the present invention.

[0043] Figure 8 It is a top view of the pouring system in the present invention.

[0044] The marks in the above figure are:

[0045] 1-1, die-casting machine, 1-2 holding furnace, 1, pouring system, 11, external gate, 12, runner, 13, internal gate. DETAILED DESCRIPTION

[0046] The specific implementation of the present invention will be further explained in detail below by describing the optimal embodiment with reference to the accompanying drawings.

[0047] A one-piece lower body double-shot die-casting process comprises the following steps:

[0048] Step 1: Select a die-casting mold; the die-casting mold has a gating system 1;

[0049] The pouring system 1 comprises a pouring cavity 14; a pouring system 101 connected to the pouring cavity 14 is symmetrically distributed on both sides of the pouring cavity 14;

[0050] The pouring system 101 includes an external gate 11, a runner 12 and an internal gate 13; the external gate 11 is connected to the internal gate 13 through the runner 12; the internal gate 13 is connected to the pouring cavity 14;

[0051] Step 2: Inspect the die-casting machine 1-1;

[0052] Step 3: Spray an isolation layer in the die casting mold cavity;

[0053] Step 4: The pouring liquid enters the barrel corresponding to the die-casting machine 1-1; the die-casting machine 1-1 includes two independent injection systems; the pouring liquid is injected by the injection system into the pouring system 1;

[0054] Step 5: Die-casting mold closing: After the casting liquid fills the die-casting mold cavity, the die-casting machine 1-1 is used to die-cast the parts into one piece. The parts are cooled and taken out by the picking robot. The production of one part is completed. If new parts need to be produced, the next cycle can be started.

[0055] The present invention is mainly a high-pressure die-casting process through the double-shot die-casting process of the one-piece lower body.

[0056] In the present invention, the casting liquid is generally aluminum liquid.

[0057] The present invention can realize the one-piece molding of the lower body at one time through the implementation of the above-mentioned die-casting process, which greatly speeds up the production efficiency of the lower body.

[0058] At the same time, the die-casting machine 1-1 of the present invention has two independent injection systems and cooperates with the double-injection position pouring system 1 at the same time; it can form a symmetrical filling for the filling of the integrated lower body; it can not only ensure the pouring efficiency of the lower body, but also the two pouring systems 101 inject aluminum liquid through hedging, which can also ensure the uniformity of aluminum liquid mixing.

[0059] At the same time, the liquid enters through the wheel arch of the lower body; thus greatly reducing the risk of cracking at the SPR connection.

[0060] In the present invention, the specific process steps are as follows:

[0061] S1: Select a die-casting mold and install a barrel on the fixed mold template. Because the present invention is a double-shot injection, the present invention has two barrels, and the two barrels are respectively connected to the two pouring systems 101;

[0062] Specifically, the mold fixed die is installed on the dynamic and fixed die plates of the die-casting machine 1-1; the dynamic and fixed die plates need to be installed on a press with dual-shot capability;

[0063] The pouring system 1 of the present invention comprises a pouring cavity 14; a pouring system 101 connected to the pouring cavity 14 is symmetrically distributed on both sides of the pouring cavity 14; the pouring system 101 comprises an external gate 11, a runner 12 and an internal gate 13; the external gate 11 is connected to the internal gate 13 through the runner 12; the internal gate 13 is connected to the pouring cavity 14;

[0064] The pouring system 1 disclosed in the present invention includes an external gate 11, which is mainly composed of two cakes; the cake thickness is about 40±5mm and the diameter is ≥280mm. This size can greatly improve the gate ratio of the pouring system 1, increase the thickness of the internal gate 13 during die casting, and prevent the cake from bursting during the production process.

[0065] Runner 12: The horizontal runner 12 is directed upward in the opposite direction of gravity, and the cross-sectional area gradually decreases. The runner 12 includes a main runner 121 and a branch runner 122. The main runner 121 is then divided into two branch runners 122. The cross-sectional areas of the two branch runners 122 are also gradually reduced, so as to improve the acceleration effect of the aluminum liquid in the runner. The branch runner is connected with 10 monomer internal gates 131.

[0066] During subsequent use, the molten aluminum will first enter the edge of the wheel arch flange and fill the edge of the wheel arch preferentially. Compared with the traditional center pouring and single-side pouring, the wheel arch is changed from the filling end to the filling starting position, thereby reducing the risk of insufficient filling. In addition, the edge of the wheel arch is close to the gate and can obtain sufficient pressurization capacity. The density of the wheel arch edge is higher, which can reduce the risk of defects at the edge of the wheel arch, thereby improving the mechanical properties of the product. Then the molten aluminum enters the lower body from the edge of the wheel arch to fill the integrated lower body, and the filling distance is also close.

[0067] In addition, the traditional one-piece lower body pouring method is limited to the center pouring, and the gate area that can be arranged is small. The inner gate area is generally ≤5000mm 2The aluminum liquid flow is relatively small, which will increase the overall time of aluminum liquid filling the product. The filling time is ≤120ms. During the filling process, the aluminum liquid temperature drops significantly, and the product is prone to defects such as cold shut marks. The double runner 12 is used to increase the area of ​​the inner gate 13. The overall area of ​​the inner gate 13 is ≤9000mm 2 The aluminum liquid flow rate is about twice that of the original product, and the overall filling time of the product is ≤70ms. During the filling process, the aluminum liquid temperature drops less, and the risk of defects such as cold shut marks on the product is greatly reduced;

[0068] Slag bag 16: Slag bag 16 is located in the middle of the product, where the aluminum liquid converges. The volume of slag bag 16 is about 5%-8% of the total weight of the product. It can effectively collect the aluminum temperature at the end of the product to reduce the relatively low temperature of the product;

[0069] The gate 13 is a conformal gate 13. The double-shot gate 13 is designed in a completely conformal manner. The entire gate is arranged completely according to the shape of the edges on both sides of the lower body, which not only greatly increases the entire filling area of ​​the product, but also directly fills the edges of the product, effectively improving the mechanical properties such as the elongation of the wheel cover, especially the elongation performance. The higher the elongation, the lower the risk of SPR cracking, thereby greatly improving the qualified rate of SPR connection;

[0070] S2: Check the die-casting machine 1-1 to ensure that the equipment is in normal working condition; preset 10 sections of injection position and speed, select the boost trigger position, cooling time, core pulling action sequence and speed, product ejection position and ejection force, mold opening and locking action position, punch lubrication position and lubrication amount, start the equipment, monitor the injection curve, and adjust and optimize the above process parameters in real time. Compared with the traditional single injection curve, the control system needs to adjust the two-group injection system;

[0071] S3: Spray the mold surface by micro-spraying to produce a uniform isolation layer on the mold surface to facilitate subsequent demoulding;

[0072] S4: The aluminum liquid is poured into the barrel through the machine-side holding furnace 1-2. The die-casting machine 1-1 is composed of two independent injection systems. The injection systems follow the master-slave control mode. After the aluminum liquid enters the injection barrel, synchronous injection is performed, and the injection synchronization is ≤20ms;

[0073] S5: The mold is closed, and after the aluminum liquid fills the cavity, the die-casting machine 1-1 is used to die-cast the mold into one piece. The parts are cooled, and the parts are taken out by the picking robot to start the next cycle.

[0074] S6: The present invention relates to two machine-side holding furnaces 1-2, the weight of the aluminum liquid is controlled by a liquid level sensor on the furnace body, such as Figure 6As shown, after the injection command is issued, by controlling the pressure and time of the liquid lifting pump, the weight difference of the aluminum liquid in the two machine-side insulation furnaces 1-2 needs to be guaranteed to be ±1%, and the temperature of the two aluminum liquids is ≤3°C.

[0075] Furthermore, in step 4 of the present invention, the pouring liquid is kept warm in the insulation furnace 1-2 before entering the die-casting mold; each pouring system 101 is connected to a insulation furnace 1-2; such a setting can ensure the constancy of the pouring liquid. At the same time, in the present invention, the weight difference of the pouring liquid in the two insulation furnaces 1-2 is not higher than 1%; the temperature difference of the pouring liquid in the two insulation furnaces 1-2 is not higher than 3°C; based on such a setting, the consistency of the subsequent pouring temperature of the two pouring systems 101 can be ensured, avoiding excessive casting defects caused by excessive temperature difference between the two pouring liquids.

[0076] Furthermore, in step 3 of the present invention, the isolation layer is sprayed on the mold by pulse micro-spraying; pulse micro-spraying is a high-precision spraying technology that uses a tiny nozzle and a low-flow spraying device to accurately spray the release agent onto the mold surface to form a lubricating isolation film. Compared with the traditional continuous spraying method, this technology can significantly reduce the amount of release agent used, while improving the spraying efficiency and casting quality; the pulse spraying technology uses intermittent spraying, that is, spray-stop-spray-stop-spray, which can reduce the thermal shock to the mold, reduce the temperature gradient and thermal stress of the mold, and thus increase the life of the mold. Micro-spraying technology can increase the production capacity of die castings, reduce the amount of dilution water and wastewater, extend the service life of the mold, and significantly reduce costs.

[0077] Furthermore, in step 4 described in the present invention, the two injection systems are required to synchronously inject the casting liquid in the corresponding barrels; this can ensure the synchronous liquid inflow on both sides of the casting cavity 14, and facilitate the formation of a hedge in the middle of the casting cavity 14, which is not only convenient for subsequent slag discharge, but also helps to ensure the relative speed balance of the casting liquid on both sides, and helps to ensure the uniformity of mixing of the two casting liquids.

[0078] Furthermore, in the present invention, the pouring system 1 includes a pouring cavity 14; the pouring cavity 14 is symmetrically distributed with a pouring system 101 connected to the pouring cavity 14 on both sides; the pouring system 1 disclosed in the present invention is mainly suitable for high-pressure die-casting process, and the present invention uses a double pouring system 101 and a completely symmetrical pouring system 101 to form a symmetrical filling of the one-piece lower body; not only can the pouring efficiency of the lower body be guaranteed, but also the two pouring systems 101 inject aluminum liquid through hedging, and the uniformity of aluminum liquid mixing can be guaranteed.

[0079] Specifically, the pouring system 1 disclosed in the present invention mainly includes a pouring cavity 14; the pouring cavity 14 is used for liquid injection molding of the lower body; at the same time, the pouring system 101 connected to the pouring cavity 14 is symmetrically distributed on both sides of the pouring cavity 14 in the present invention; the pouring system 101 of the present invention is a runner 12 system; through the above design, the present invention enables the pouring system 1 to have two sets of runner 12 systems, which can greatly improve the mechanical properties of the two ends of the lower body, and the elongation is the key factor for the qualified SPR connection, thereby greatly improving the qualified rate of the SPR connection points of the product.

[0080] At the same time, in the present invention, the pouring system 101 includes an external gate 11, a runner 12 and an internal gate 13; the external gate 11 is connected to the internal gate 13 through the runner 12; the internal gate 13 is connected to the pouring cavity 14; the coordinated use of the external gate 11, the runner 12 and the internal gate 13 can realize the liquid inlet operation of the aluminum liquid, which facilitates the subsequent pouring and molding of the lower body.

[0081] Furthermore, the gate 13 in the present invention includes multiple single gates 131; the single gates 131 in each gate 13 are distributed in sequence on the side of the lower body along the X-axis direction of the lower body; based on such a setting, the lower body can have multiple liquid inlet points in the X-axis direction of the body, which can speed up the punching speed of the casting cavity 14; at the same time, due to the increase in the punching speed, the temperature of the aluminum liquid decreases less during the subsequent filling process, and the risk of defects such as cold shut flow marks in the product is greatly reduced.

[0082] In addition, in the present invention, the inner gate 13 is a running inner gate 13; the double-shot inner gate 13 of the present invention is designed in a completely conformal manner, and the entire gate is arranged completely according to the edge shape of the lower vehicle body on both sides, which not only greatly increases the entire filling area of ​​the product, but also directly fills the edge of the product, effectively improving the mechanical properties such as the elongation of the wheel cover, especially the elongation performance. The higher the elongation, the lower the risk of SPR cracking, thereby greatly improving the qualified rate of SPR connection.

[0083] Furthermore, in the present invention, the runner 12 includes a main runner 121 and two branch runners 122; the main runner 121 is connected to the corresponding inner gate 13 through the two branch runners 122; the main runner 121 is mainly used to connect with the outer gate 11, and the branch runners 122 are distributed along the side length direction of the pouring cavity 14; such a setting can increase the area of ​​the inner gate 13 to a certain extent and optimize the liquid inlet speed of the pouring cavity 14; at the same time, through the use of the branch runner 122, it is convenient to divert the aluminum liquid coming in from the main runner 121, and facilitate the liquid injection operation of multiple positions of the inner gate 13.

[0084] Furthermore, in the present invention, the cross-sectional area of ​​the runner 12 gradually decreases from the outer gate 11 to the corresponding inner gate 13; such a setting can speed up the flow speed of the molten aluminum in the runner 12; optimize the aluminum liquid punching speed, ensure that the aluminum liquid temperature drops less during the filling process, and greatly reduce the risk of defects such as cold shut flow marks in the product.

[0085] Furthermore, the main runner 121 described in the present invention is arranged at an angle when in use; the main runner 121 is arranged at an angle, which facilitates the flow of molten aluminum in the main runner 121. At the same time, an arc surface transition is adopted at the connection between the main runner 121 and the branch runner 122 described in the present invention; such a setting can reduce the excessive running resistance formed by the molten aluminum at the connection between the main runner 121 and the branch runner 122 when the main runner 121 is diverted to the branch runner 122.

[0086] Furthermore, in the present invention, the monomer inner gate 131 near the connection between the main runner 121 and the branch runner 122 has a flow limiting corner 132; because the liquid inlet speed of the monomer inner gate 131 near the connection between the main runner 121 and the branch runner 122 is relatively large, in order to reduce the flow rate of the monomer inner gate 131 at this location, a flow limiting corner 132 is set through the monomer inner gate 131 at this location, thereby reducing the flow rate in the monomer inner gate 131 at this location; try to ensure the consistency of the aluminum liquid entering the casting cavity 14, and avoid the aluminum liquid flow rate between adjacent monomer inner gates 131. Too large a difference in each other to generate eddy currents, causing subsequent casting defects of the lower body.

[0087] Furthermore, in the present invention, the connection between the branch runner 122 and each monomer ingate 131 adopts an arc surface transition; such a setting can reduce the running resistance at the connection between the branch runner 122 and each corresponding monomer ingate 131.

[0088] Furthermore, in the present invention, a confluence area 102 is formed in the middle area of ​​the pouring cavity 14; the liquid in the pouring system 101 impacts each other in the confluence area 102; with such a configuration, during the subsequent filling operation, the two streams of aluminum liquid provided by the two pouring systems 101 instantly impact and impact each other, generating a large impact energy, effectively causing the two streams of aluminum liquid to fuse, reducing aluminum liquid fusion defects, and greatly improving the mechanical properties of the product, especially on both sides of the front floor and the wheel arch of the lower body, thereby greatly reducing the risk of cracking at the SPR connection.

[0089] Furthermore, the pouring system 1 in the present invention also includes a slag bag 16 arranged in the middle area of ​​the pouring cavity 14; the slag bag 16 is located in the middle of the product, where the aluminum liquid converges, and the volume of the slag bag 16 is approximately 5%-8% of the total weight of the product, which can effectively collect the aluminum temperature at the end of the product to reduce the temperature of the product to a relatively low cold material.

[0090] In the present invention, the total volume of the slag bag 16 is V1; the volume of the confluence area 102 is V2; V1 is required to be not less than V2; the end cold material of the product confluence area 102 volume can be discharged into the slag bag 16 to the maximum extent; even if the confluence area 102 is not in the center of the product, the end cold material can be discharged into the slag bag 16; and the use effect of the pouring system 1 is optimized.

[0091] Furthermore, in the present invention, the liquid inlet speeds of the single body inner gates 131 connected to the same area of ​​the lower body are the same; such a setting can ensure the consistency of the aluminum liquid entering the same area of ​​the lower body through the corresponding single body inner gates 131 into the pouring cavity 14, and avoid the aluminum liquid flow rate of the corresponding single body inner gates 131 in the same area is too different to generate eddy currents in the pouring cavity 14, resulting in subsequent casting defects of the lower body; affecting the high-pressure die-casting effect of the lower body.

[0092] Furthermore, in the present invention, the pouring system 1 is arranged longitudinally, and the pouring system 101 in the pouring system 1 is pre-filled with liquid through the lower body wheel arch; based on such a design, the molten aluminum can preferentially enter the edge of the wheel arch flange, and preferentially fill the edge of the wheel arch. Compared with the traditional center pouring and single-side pouring, the wheel arch is the filling end and becomes the filling starting position, thereby reducing the risk of insufficient filling. In addition, the edge of the wheel arch is close to the inner gate 13, and sufficient pressurization capacity can be obtained, and the tissue density of the wheel arch edge is higher; at the same time, through the liquid filling at the lower body wheel arch; the risk of cracking at the SPR connection is greatly reduced.

[0093] specific;

[0094] The present invention discloses a high-pressure dual-shot pouring system 1 for an integrated lower body; the integrated lower body adopts a dual-shot pouring system 101, and a completely symmetrical pouring system 101 is adopted to form a symmetrical filling for the integrated lower body. The filling time of the traditional single-sided filling method is ≥100ms, and the filling time of the dual-shot method can be shortened to ≤70ms, which greatly expands the die-casting process window and reduces the debugging difficulty of on-site process personnel.

[0095] In addition, the entire ingates 13 in the pouring system 101 of the present invention are arranged along the outer contour of the lower vehicle body, and the conformal ingates 13 are arranged to form a completely symmetrical structure, which can greatly shorten the distance from the ingates 13 to both sides of the lower vehicle body. At the same time, after filling, the two streams of aluminum liquid instantly impact and collide with each other, generating a large impact energy, which effectively causes the aluminum liquid to fuse, reduces aluminum liquid fusion defects, and greatly improves the mechanical properties of the product, especially on both sides of the front floor and the wheel arch of the lower vehicle body, thereby greatly reducing the risk of cracking at the spr connection.

[0096] Example 1 is as follows:

[0097] The pouring system 1 disclosed in the present invention includes an external gate 11, which is mainly composed of two cakes; the cake thickness is about 40±5mm and the diameter is ≥280mm. This size can greatly improve the gate ratio of the pouring system 1, increase the thickness of the internal gate 13 during die casting, and prevent the cake from bursting during the production process.

[0098] Runner 12: The horizontal runner 12 is directed upward in the opposite direction of gravity, and the cross-sectional area gradually decreases. The runner 12 includes a main runner 121 and a branch runner 122. The main runner 121 is then divided into two branch runners 122. The cross-sectional areas of the two branch runners 122 are also gradually reduced, so as to improve the acceleration effect of the aluminum liquid in the runner. The branch runner is connected with 10 monomer internal gates 131.

[0099] During subsequent use, the molten aluminum will first enter the edge of the wheel arch flange and fill the edge of the wheel arch preferentially. Compared with the traditional center pouring and single-side pouring, the wheel arch is changed from the filling end to the filling starting position, thereby reducing the risk of insufficient filling. In addition, the edge of the wheel arch is close to the gate and can obtain sufficient pressurization capacity. The density of the wheel arch edge is higher, which can reduce the risk of defects at the edge of the wheel arch, thereby improving the mechanical properties of the product. Then the molten aluminum enters the lower body from the edge of the wheel arch to fill the integrated lower body, and the filling distance is also close.

[0100] In addition, the traditional one-piece lower body pouring method is limited to the center pouring, and the gate area that can be arranged is small. The inner gate area is generally ≤5000mm 2 The aluminum liquid flow is relatively small, which will increase the overall time of aluminum liquid filling the product. The filling time is ≤120ms. During the filling process, the aluminum liquid temperature drops significantly, and the product is prone to defects such as cold shut marks. The double runner 12 is used to increase the area of ​​the inner gate 13. The overall area of ​​the inner gate 13 is ≤9000mm 2 The aluminum liquid flow rate is about twice that of the original product, and the overall filling time of the product is ≤70ms. During the filling process, the aluminum liquid temperature drops less, and the risk of defects such as cold shut flow marks in the product is greatly reduced.

[0101] Slag bag 16: Slag bag 16 is located in the middle of the product, where the aluminum liquid converges. The volume of slag bag 16 is about 5%-8% of the total weight of the product. It can effectively collect the aluminum temperature at the end of the product and reduce the temperature of the product to a relatively low cold material.

[0102] The gate 13 is a conformal gate 13, and the double-shot gate 13 is designed in a completely conformal manner. The entire gate is arranged completely according to the edge shape of the lower body, which not only greatly increases the entire filling area of ​​the product, but also directly fills the edge of the product, effectively improving the mechanical properties of the wheel cover such as the elongation, especially the elongation performance. The higher the elongation, the lower the risk of SPR cracking, thereby greatly improving the qualified rate of SPR connection.

[0103] At the same time, in the present invention, the middle confluence area 102 of the product includes the product and the slag bag 16 part, the total volume of the slag bag 16 is V1, the volume of the product confluence part is V2, V1≥V2, and the end cold material of the product confluence part volume can be discharged into the slag bag 16 to the maximum extent; even if the confluence part is not in the center of the product, the end cold material can be discharged into the slag bag 16.

[0104] The die-casting process disclosed in the present invention meets the molding process requirements of die-casting parts with ultra-large projection areas and can perform die-casting molding on ultra-large integrated integral vehicle bodies.

[0105] The die-casting machine 1-1 is composed of two independent injection systems. The injection systems follow the master-slave control mode to achieve synchronization of the aluminum liquid filling process. According to the product filling time and the confluence and fusion area, a double-runner 12-filling confluence overflow system and a vacuum exhaust structure design are designed. According to the aluminum liquid demand of the parts, aluminum liquid of the same weight and temperature is provided to the two barrels from the two machine-side insulation furnaces 1-2 respectively. Synchronous injection is performed through the two injection systems, and the aluminum liquid in the two barrels is pushed into the mold cavity at the same speed. The aluminum liquid is solidified and formed by uniform cooling of the mold and taken out to obtain a complete part.

[0106] Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, they are all within the protection scope of the present invention.

Claims

1. A one-piece lower body double-shot die-casting process, characterized in that; The steps include: Step 1: Select a die-casting mold; the die-casting mold has a gating system; The pouring system comprises a pouring cavity; a pouring system connected to the pouring cavity is symmetrically distributed on both sides of the pouring cavity; The pouring system includes an external gate, a runner and an internal gate; the external gate is connected to the internal gate through the runner; the internal gate is connected to the pouring cavity; Step 2: Inspect the die casting machine; Step 3: Spray an isolation layer in the die casting mold cavity; Step 4: The pouring liquid enters the corresponding barrel of the die-casting machine; the die-casting machine includes two independent injection systems; The pouring liquid is injected into the pouring system by the injection system; Step 5: Die-casting mold closing: After the casting liquid fills the die-casting mold cavity, the die-casting machine is used to die-cast the parts into one piece. The parts are cooled and taken out by the picking robot. The production of one part is completed. If new parts need to be produced, the next cycle can be started.

2. The one-piece lower body double-shot die-casting process according to claim 1, characterized in that; In the step 4, the pouring liquid is kept warm in a heat preservation furnace before entering the die casting mold; each pouring system is connected to a heat preservation furnace.

3. The one-piece lower body double-shot die-casting process according to claim 2, characterized in that; The weight difference of the pouring liquid in the two holding furnaces is not higher than 1%; the temperature difference of the pouring liquid in the two holding furnaces is not higher than 3°C.

4. The one-piece lower body double-shot die-casting process according to claim 1, characterized in that; In step 3, the isolation layer is sprayed on the mold by pulse micro-spraying.

5. The one-piece lower body double-shot die-casting process according to claim 1, characterized in that; In step 4, the two injection systems are required to inject the casting liquid in the corresponding barrels synchronously.

6. The one-piece lower body double-shot die-casting process according to claim 1, characterized in that; The ingates all include multiple single ingates; each single ingate in each ingate is distributed in sequence on the side of the lower body along the X-axis direction of the lower body; the ingate is a trailing ingate.

7. The one-piece lower body double-shot die-casting process according to claim 1, characterized in that: The runner includes a main runner and two branch runners; the main runner is connected to the corresponding inner gate through the two branch runners. The cross-sectional area of ​​the runner gradually decreases from the outer gate to the corresponding inner gate.

8. The one-piece lower body double-shot die-casting process according to claim 1, characterized in that: The middle area of ​​the pouring cavity forms a confluence area; In the pouring system, the liquid flowing into the pouring system is offset in the confluence area. The pouring system further comprises a slag bag arranged in the middle area of ​​the pouring cavity; the total volume of the slag bag is V1; The volume of the confluence area is V2; V1 is required to be no less than V2.

9. The one-piece lower body double-shot die-casting process according to claim 6, characterized in that: The liquid inlet speed of the monomer ingates connected to the same area of ​​the lower body is the same.

10. The one-piece lower body double-shot die-casting process according to claim 6, characterized in that: The pouring system is arranged in the longitudinal direction, and the pouring system in the pouring system is pre-filled with liquid through the wheel housing of the lower vehicle body.

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