Multi-positioning step parting low-pressure casting mold

Abstract

The utility model discloses a multi-positioning step parting low-pressure casting mold which comprises a mold body, the mold body is of a left-right parting main body structure made of ZG310-570 cast steel, and the left-right parting main body structure comprises a left upper half mold, a left lower half mold, a right upper half mold and a right lower half mold. The left-right parting main body structure is transversely provided with a left-right symmetrical parting surface and is longitudinally provided with a curved surface step parting surface with a 35-degree dip angle. The repeated positioning precision of the mold is improved to + / -1mm through a three-stage positioning system, the position precision of a multidirectional boss is improved by 60%, the error rate is reduced by 30%, the product percent of pass reaches 96.5% by combining effective limiting of a curved surface step parting surface on a boss on the outer surface of a casting, and meanwhile, by means of the synergistic effect of a composite exhaust system and a longitudinal grading water gap system, the product quality is improved. And the air hole defect rate is controlled to be below 0.8%, the feeding problem at the hot spot is effectively solved, the casting quality and the production efficiency are remarkably improved, and the production requirements of high-end precision castings are met.

Description

Technical Field

[0001] This utility model relates to the field of metal casting technology, and in particular to a multi-positioning stepped parting low-pressure casting mold, which is especially suitable for the production of precision castings with multi-directional bosses, such as the housing of new energy vehicle motors. Background Technology

[0002] In the field of metal casting technology, low-pressure casting molds are widely used in the production of precision castings such as automotive parts and mechanical equipment. However, traditional low-pressure casting molds have many technical bottlenecks: First, the parting surface positioning accuracy is insufficient, and positioning deviations are prone to occur during multiple mold opening and closing processes, making it difficult to guarantee the dimensional accuracy of the castings; Second, for complex castings with multi-directional bosses, such as the motor housing of new energy vehicles, traditional molds cannot effectively restrict the displacement of the bosses during forming, resulting in excessive positional tolerances between the bosses and frequent misalignment problems; Third, venting and feeding of complex cavities are difficult, and gas is difficult to escape during the filling of molten metal, easily causing defects such as porosity and shrinkage at hot spots in the castings, resulting in a high scrap rate. With the continuous improvement of the requirements for the quality and production efficiency of precision castings in high-end manufacturing industries such as new energy vehicles, traditional low-pressure casting molds can no longer meet the industry's needs, and innovative designs are urgently needed to overcome technical limitations.

[0003] To address this, we propose a multi-positioning stepped parting low-pressure casting mold. Utility Model Content

[0004] The main objective of this invention is to provide a multi-positioning stepped parting low-pressure casting mold. This mold aims to prevent problems such as insufficient dimensional accuracy of castings due to parting surface positioning deviations, positional errors and misalignments caused by multi-directional boss forming displacement, and porosity and shrinkage due to poor venting and feeding difficulties in complex cavities. This improves the dimensional accuracy, positional accuracy, and forming quality of castings, while reducing the scrap rate. Simultaneously, through an efficient venting and feeding design, defects caused by residual gas and solidification shrinkage are reduced, increasing the product qualification rate to 96.5%. This meets the high-quality and high-efficiency production requirements of precision castings in high-end manufacturing industries such as new energy vehicles, breaking through the technical limitations of traditional low-pressure casting molds and effectively solving the problems in the background technology.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] A multi-positioning stepped parting low-pressure casting mold includes a mold body. The mold body is made of ZG310-570 cast steel and has a left and right parting main structure. The left and right parting main structure includes an upper left mold, a lower left mold, an upper right mold, and a lower right mold. The left and right parting main structure has a symmetrical parting surface arranged laterally and a curved stepped parting surface with a 35° inclination angle arranged longitudinally. The curved stepped parting surface concentrates the bosses on the outer surface of the casting in the forming areas of the lower left mold and the lower right mold.

[0007] The mold body also includes a first movable block, a second movable block, a base plate, and an inner sand core composed of a resin-silica composite core. The base plate and the inner sand core are positioned by a positioning structure. The positioning structure includes a positioning core head set at the bottom of the inner sand core and a corresponding positioning groove on the base plate. The positioning groove is provided with a positioning pin. The clearance fit tolerance between the positioning pin and the pin hole on the inner sand core is ±0.5mm.

[0008] The mold body parting surface is equipped with a three-level positioning system, including four sets of Φ20mm tapered guide pillars arranged on the main parting surface, four sets of Φ20mm tapered guide pillars set on the curved stepped surface, and the installation, positioning and locking structure of the first movable block 3 and the second movable block 7.

[0009] By adopting the above technical solution, the inner sand core is first precisely assembled with the bottom positioning core head and the positioning groove and positioning pin of the base plate to ensure an assembly accuracy of ±1mm. Then, the lower left half mold and the lower right half mold are installed in sequence. The four sets of Φ20mm tapered guide pillars at the four corners of the main parting surface and the guide sleeves are fitted with a clearance of 0.05-0.1mm to complete the rough positioning. Then, the upper left half mold and the upper right half mold are closed. The four sets of Φ20mm tapered guide pillars on the curved stepped surface are fitted with a clearance of 0.03-0.08mm to achieve precise positioning, ensuring that the overall repeatability of the mold positioning accuracy reaches ±1mm. Next, the first movable block and the second movable block are slid into the lower left half mold and the lower right half mold along the T-slot. The mold assembly is completed by tightening the inclined surface at a slope of 1:50 and the bolts. After the mold is closed, The molten metal is introduced into the mold cavity through the riser pipe. Under low pressure, the molten metal fills the longitudinal sprue. The curved stepped parting surface uses a step height difference of 5-10mm and a horizontal distance of 15-25mm to form a limit. Combined with a curvature radius of 1000-1500mm, the positional accuracy of the boss on the outer surface of the casting in the lower left and lower right mold forming areas is improved by 60%, and the misalignment rate is reduced by 30%. At the same time, the composite venting system works in conjunction with the venting grooves and risers at the top of the casting to reduce the porosity defect rate to below 0.8%. After the casting solidifies and cools, the movable block bolt is loosened, the movable block is pulled out along the T-slot, the parting surface is opened, and the casting is removed. If different structural products need to be produced, the movable block can be quickly replaced to achieve flexible assembly of the product head.

[0010] Furthermore, the step height difference of the curved stepped parting surface is 5-10mm, and the horizontal distance between adjacent steps is 15-25mm. The curvature radius of the curved stepped parting surface is 1000-1500mm. The limiting effect of the curved stepped parting surface ensures that the positional error between the bosses is ≤±1mm.

[0011] By adopting the above technical solution, the unique geometric parameters of the curved stepped parting surface form a three-dimensional limiting structure during the process of molten metal filling the cavity. This structure can effectively offset the impact force of molten metal flow and solidification shrinkage stress, and avoid boss offset or misalignment. Compared with traditional planar parting, this design significantly improves the positional accuracy of the boss by 60% and reduces the misalignment rate by 30%. It is especially suitable for precision castings of multi-directional bosses such as motor housings for new energy vehicles, ensuring that the key dimensions of the product meet the standards.

[0012] Furthermore, in the three-level positioning system, the four sets of tapered guide pillars on the main parting surface are distributed at the four corners of the mold, and the fit clearance between the guide pillars and the guide sleeves is 0.05-0.1mm. The four sets of tapered guide pillars on the curved stepped surface are evenly distributed along the stepped direction, and the fit clearance between the guide pillars and the guide sleeves is 0.03-0.08mm.

[0013] By adopting the above technical solutions, the main parting surface guide pillars achieve rapid mold closing guidance with a larger gap of 0.05-0.1mm, while the curved stepped surface guide pillars complete the final positioning calibration with a more precise gap of 0.03-0.08mm. This dual guarantee ensures that the mold's repeatability positioning accuracy remains stable at ±1mm. Even after long-term, high-frequency mold opening and closing operations, the positioning accuracy can still be maintained, significantly improving the product qualification rate to 96.5% and reducing scrap losses caused by positioning deviations.

[0014] Furthermore, the first and second movable blocks are slidably connected to the lower left and lower right half molds respectively via T-slots, and locked to the lower left and lower right half molds by bolts. The positioning surfaces of the first and second movable blocks with the lower left and lower right half molds are inclined surfaces with an inclination of 1:50.

[0015] By adopting the above technical solution, the combination structure of the inclined surface and the T-slot gives the movable block a dual positioning function: the inclined surface generates lateral extrusion force when the bolt is tightened, ensuring that the movable block is stable and does not shift under the impact of molten metal; the T-slot provides a quick disassembly and assembly channel, and when different structural products need to be produced, the movable block can be disassembled and replaced within a certain time, realizing flexible switching of the product head and significantly improving the mold's adaptability to complex casting structures.

[0016] Furthermore, the positioning structure between the base plate and the inner sand core achieves an assembly accuracy of ±1mm.

[0017] By adopting the above technical solution, the high-precision matching of the positioning core head, positioning groove and positioning pin ensures that the inner sand core is fixed in the mold, avoiding the out-of-tolerance of the inner cavity size of the casting due to offset. This positioning accuracy ensures the forming quality of the internal structure of complex thin-walled castings. Combined with the composite venting system, it further reduces the risk of defects such as porosity and sand holes, significantly improves the product qualification rate, and meets the stringent production standards of precision castings for new energy vehicles.

[0018] Furthermore, the mold body also includes an exhaust system, which includes an exhaust groove and an exhaust riser located at the highest point of the casting. The exhaust groove has a width of 3-5 mm and a depth of 0.2-0.5 mm, and the exhaust riser has a diameter of 10-15 mm and a height of 20-30 mm.

[0019] By adopting the above technical solution, molten metal enters the mold cavity through the riser pipe. During the filling process, the air in the cavity is first discharged through the venting grooves distributed at the highest point of the casting. The venting grooves are designed with a width of 3-5 mm and a depth of 0.2-0.5 mm to ensure rapid gas discharge and prevent molten metal from overflowing. When the molten metal is close to filling the cavity, the remaining gas is discharged through the venting riser. The venting riser with a diameter of 10-15 mm and a height of 20-30 mm can accommodate a small amount of excess molten metal, further ensuring that the gas in the cavity is completely discharged, which greatly improves the cavity venting effect and effectively controls the porosity defect rate to below 0.8%. At the same time, the venting riser can also play a feeding role during the solidification process of the molten metal, preventing shrinkage cavities from appearing on the top of the casting.

[0020] Furthermore, the mold also includes a longitudinally graded sprue system, which includes a main gating system, a transverse gating system, and an ingate system. The ingate system is divided into three levels: upper, middle, and lower. The upper ingate system is located 5-10 mm above the hot spot of the casting, the middle ingate system is located in the middle of the casting, and the lower ingate system is located at the bottom of the casting. The cross-sectional area ratio of the ingate system is 1:1.2:1.5.

[0021] By adopting the above technical solution, the molten metal enters the longitudinally graded ingate system after passing through the main gating and transverse gating. The lower ingate is located at the bottom of the casting and introduces the molten metal first, providing sufficient molten metal filling to the bottom of the casting. As the molten metal level rises, the middle ingate replenishes the molten metal in the middle of the casting, ensuring the forming quality of the middle part of the casting. The upper ingate is precisely set 5-10mm above the hot spot of the casting. Utilizing an ingate cross-sectional area ratio of 1:1.2:1.5, the upper ingate continuously replenishes the hot spot during the solidification process of the molten metal, achieving sequential solidification from bottom to top. This longitudinally graded gate distribution method effectively compensates for the defects caused by solidification shrinkage at the hot spot of the casting, ensuring that the structure of each part of the casting is dense and improving the overall quality of the casting.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) This utility model discloses a multi-positioning stepped parting low-pressure casting mold, which improves the mold's repeatability accuracy to ±1mm through a three-level positioning system. The main parting surface and the conical guide post of the curved stepped surface cooperate with the movable block positioning and locking structure to ensure that the mold maintains accurate positioning during frequent use. On this basis, the curved stepped parting surface utilizes unique geometric parameters (step height difference 5-10mm, horizontal distance 15-25mm, radius of curvature 1000-1500mm) to effectively limit the bosses on the outer surface of the casting, thereby improving the position accuracy of the multi-directional bosses by 60%, reducing the misalignment rate by 30%, and significantly increasing the product qualification rate to 96.5%, greatly reducing production costs and meeting the production requirements of high-end precision castings.

[0024] (2) This utility model discloses a multi-positioning stepped parting low-pressure casting mold, in which a composite venting system and a longitudinal graded sprue system work together. The venting system achieves rapid gas discharge from the mold cavity through venting grooves (3-5mm wide, 0.2-0.5mm deep) and venting risers (10-15mm in diameter, 20-30mm in height) at the highest point of the casting, controlling the porosity defect rate to below 0.8%. The longitudinal graded sprue system adopts a three-stage ingate layout (upper, middle, and lower), with the upper ingate precisely positioned above the hot spot. Through a cross-sectional area ratio of 1:1.2:1.5, it achieves sequential solidification from bottom to top, effectively compensating for the feeding problem at the hot spot. The combination of the two ensures that the internal structure of the casting is dense and the surface is smooth, making it particularly suitable for the production of precision castings with complex structures such as the motor housing of new energy vehicles, significantly improving product quality and performance. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of a multi-positioning stepped parting low-pressure casting mold according to the present invention.

[0026] Figure 2 This is a schematic diagram of the mold assembly structure of a multi-positioning stepped parting low-pressure casting mold according to the present invention.

[0027] Figure 3 This is a schematic diagram of the mold assembly structure of a multi-positioning stepped parting low-pressure casting mold according to the present invention.

[0028] Figure 4 This is a front view of the mold assembly of a multi-positioning stepped parting low-pressure casting mold according to the present invention, after disassembly.

[0029] Figure 5 This is a disassembled view of the mold assembly of a multi-positioning stepped parting low-pressure casting mold according to this utility model.

[0030] In the diagram: 1. Upper left half mold; 2. Lower left half mold; 3. First movable block; 4. Base plate; 5. Upper right half mold; 6. Lower right half mold; 7. Second movable block; 8. Inner sand core. Detailed Implementation

[0031] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the present utility model will be further described below in conjunction with specific embodiments.

[0032] To prevent problems such as insufficient dimensional accuracy of castings due to parting surface positioning deviation, positional errors and misshapen parts caused by multi-directional boss forming displacement, and porosity and shrinkage porosity caused by poor venting and feeding difficulties in complex cavities, thereby improving the dimensional accuracy, positional accuracy, and forming quality of castings and reducing scrap rate; at the same time, through efficient venting and feeding design, defects caused by gas residue and solidification shrinkage are reduced, increasing the product qualification rate to 96.5%, meeting the high-quality and high-efficiency production requirements of high-end manufacturing industries such as new energy vehicles, and breaking through the technical limitations of traditional low-pressure casting molds, such as... Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown, a multi-positioning stepped parting low-pressure casting mold includes a mold body. The mold body is made of ZG310-570 cast steel and has a left and right parting main structure. The left and right parting main structure includes an upper left half mold 1, a lower left half mold 2, an upper right half mold 5, and a lower right half mold 6. The left and right parting main structure has a symmetrical parting surface arranged laterally and a curved stepped parting surface with a 35° inclination angle arranged longitudinally. The curved stepped parting surface concentrates the bosses on the outer surface of the casting in the forming areas of the lower left half mold 2 and the lower right half mold 6.

[0033] The mold body also includes a first movable block 3, a second movable block 7, a base plate 4, and an inner sand core 8 composed of resin-silica composite cores. The base plate 4 and the inner sand core 8 are positioned by a positioning structure. The positioning structure includes a positioning core head set at the bottom of the inner sand core 8 and a corresponding positioning groove on the base plate 4. The positioning groove is provided with a positioning pin. The clearance fit tolerance between the positioning pin and the pin hole on the inner sand core 8 is ±0.5mm.

[0034] The mold body parting surface is equipped with a three-level positioning system, including four sets of Φ20mm tapered guide pillars arranged on the main parting surface, four sets of Φ20mm tapered guide pillars set on the curved stepped surface, and the installation, positioning and locking structure of the first movable block 3 and the second movable block 7.

[0035] In use, first, precisely assemble the inner sand core 8 with the positioning groove and positioning pin of the base plate 4 through the bottom positioning core head to ensure an assembly accuracy of ±1mm. Then, install the lower left half mold 2 and the lower right half mold 6 in sequence. Use the four sets of Φ20mm tapered guide pillars at the four corners of the main parting surface and the guide sleeve with a clearance of 0.05-0.1mm to complete the rough positioning. Then, close the upper left half mold 1 and the upper right half mold 5. The four sets of Φ20mm tapered guide pillars on the curved stepped surface with a clearance of 0.03-0.08mm achieve precise positioning, ensuring that the overall repeatability of the mold positioning accuracy reaches ±1mm. Next, the first movable block 3 and the second movable block 7 are slid into the lower left half mold 2 and the lower right half mold 6 along the T-slot. The mold assembly is completed by tightening the inclined surface at a 1:50 angle and bolts. After the mold is closed, the molten metal is introduced into the cavity through the riser pipe. Under low pressure, the molten metal fills the longitudinal sprue. The curved stepped parting surface uses a step height difference of 5-10mm and a horizontal distance of 15-25mm to form a limit. With a curvature radius of 1000-1500mm, the positional accuracy of the boss on the outer surface of the casting in the forming area of ​​the lower left half mold 2 and the lower right half mold 6 is improved by 60%, and the misalignment rate is reduced by 30%. At the same time, the composite venting system works in conjunction with the venting groove and riser at the high point of the casting to reduce the porosity defect rate to below 0.8%. After the casting solidifies and cools, the movable block bolts are loosened, the movable block is pulled out along the T-slot, and the parting surface is opened to remove the casting. If different structural products need to be produced, the movable block can be quickly replaced to achieve flexible assembly of the product head.

[0036] For example, such as Figure 4 , Figure 5 As shown, the present invention also includes the following: the step height difference of the curved stepped parting surface is 5-10mm, and the horizontal distance between adjacent steps is 15-25mm; the radius of curvature of the curved stepped parting surface is 1000-1500mm; and the limiting effect of the curved stepped parting surface ensures that the positional error between the bosses is ≤±1mm.

[0037] During use, the unique geometric parameters of the curved stepped parting surface form a three-dimensional limiting structure during the process of molten metal filling the cavity. This structure can effectively counteract the impact force of molten metal flow and solidification shrinkage stress, preventing boss offset or misalignment. Compared with traditional planar parting, this design significantly improves the positional accuracy of the boss by 60% and reduces the misalignment rate by 30%. It is especially suitable for precision castings of multi-directional bosses such as motor housings for new energy vehicles, ensuring that the key dimensions of the product meet the standards.

[0038] For example, such as Figure 4 , Figure 5 As shown, this utility model also includes, in the three-level positioning system, four sets of tapered guide pillars on the main parting surface are distributed at the four corners of the mold, and the fit clearance between the guide pillars and the guide sleeves is 0.05-0.1mm; four sets of tapered guide pillars on the curved stepped surface are evenly distributed along the stepped direction, and the fit clearance between the guide pillars and the guide sleeves is 0.03-0.08mm.

[0039] During use, the main parting surface guide pillars achieve rapid mold closing guidance with a larger gap of 0.05-0.1mm, while the curved stepped surface guide pillars complete the final positioning calibration with a more precise gap of 0.03-0.08mm. This dual protection ensures that the mold's repeatability positioning accuracy remains stable at ±1mm. Even after long-term, high-frequency mold opening and closing operations, the positioning accuracy can still be maintained, significantly improving the product qualification rate to 96.5% and reducing scrap losses caused by positioning deviations.

[0040] For example, such as Figure 1 As shown, the present invention also includes the first movable block 3 and the second movable block 7 being slidably connected to the lower left half mold 2 and the lower right half mold 6 respectively through a T-slot, and locked to the lower left half mold 2 and the lower right half mold 6 by bolts. The positioning surfaces of the first movable block 3 and the second movable block 7 with the lower left half mold 2 and the lower right half mold 6 are inclined surfaces with an inclination of 1:50.

[0041] When in use, the combination of the inclined surface and the T-slot gives the movable block a dual positioning function: the inclined surface generates lateral extrusion force when the bolts are tightened, ensuring that the movable block remains stable and does not shift under the impact of molten metal; the T-slot provides a quick disassembly and assembly channel, so that when different structural products need to be produced, the movable block can be disassembled and replaced within a certain time, realizing flexible switching of the product head and significantly improving the mold's adaptability to complex casting structures.

[0042] For example, such as Figure 1 As shown, this utility model also includes a positioning structure between the base plate 4 and the inner sand core 8 to achieve an assembly accuracy of ±1mm.

[0043] During use, the high-precision matching of the positioning core head, positioning groove and positioning pin ensures that the inner sand core is fixed in the mold, avoiding the casting cavity dimensional deviation caused by offset. This positioning accuracy ensures the forming quality of the internal structure of complex thin-walled castings. Combined with the composite venting system, it further reduces the risk of defects such as porosity and sand holes, significantly improving the product qualification rate and meeting the stringent production standards of precision castings for new energy vehicles.

[0044] For example, such as Figure 1 , Figure 4 , Figure 5 As shown, the mold body also includes an exhaust system, which includes an exhaust groove and an exhaust riser located at the highest point of the casting. The exhaust groove has a width of 3-5 mm and a depth of 0.2-0.5 mm, and the exhaust riser has a diameter of 10-15 mm and a height of 20-30 mm.

[0045] During use, molten metal enters the mold cavity through the riser pipe. During the filling process, the air in the cavity is first discharged through the venting grooves distributed at the highest point of the casting. The venting grooves are designed with a width of 3-5mm and a depth of 0.2-0.5mm to ensure rapid gas discharge while preventing molten metal from overflowing. When the molten metal is close to filling the cavity, the remaining gas is discharged through the venting riser. The venting riser with a diameter of 10-15mm and a height of 20-30mm can accommodate a small amount of excess molten metal, further ensuring that the gas in the cavity is completely discharged, which greatly improves the cavity venting effect and effectively controls the porosity defect rate to below 0.8%. At the same time, the venting riser can also play a feeding role during the solidification process of the molten metal, preventing shrinkage cavities from appearing on the top of the casting.

[0046] For example, such as Figure 1 , Figure 4 , Figure 5 As shown, the mold also includes a longitudinally graded sprue system, which includes a main gating system, a transverse gating system, and an ingate system. The ingate system is divided into three levels: upper, middle, and lower. The upper ingate system is located 5-10 mm above the hot spot of the casting, the middle ingate system is located in the middle of the casting, and the lower ingate system is located at the bottom of the casting. The cross-sectional area ratio of the ingate system is 1:1.2:1.5.

[0047] In operation, molten metal enters the longitudinally graded ingate system after passing through the main gating and transverse gating. The lower ingate, located at the bottom of the casting, introduces molten metal first, providing sufficient filling to the bottom. As the molten metal level rises, the middle ingate replenishes the middle of the casting, ensuring the forming quality of the middle section. The upper ingate is precisely positioned 5-10mm above the hot spot of the casting. Utilizing an ingate cross-sectional area ratio of 1:1.2:1.5, the upper ingate continuously feeds the hot spot during the solidification process, achieving sequential solidification from bottom to top. This longitudinally graded ingate distribution effectively compensates for defects caused by solidification shrinkage at the hot spot, ensuring a dense structure in all parts of the casting and improving the overall quality of the casting.

[0048] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A multi-positioning stepped parting low-pressure casting mold, comprising a mold body, characterized in that, The mold body is made of ZG310-570 cast steel and has a left and right parting main structure. The left and right parting main structure includes a left upper half mold (1), a left lower half mold (2), a right upper half mold (5) and a right lower half mold (6). The left and right parting main structure has a left and right symmetrical parting surface in the horizontal direction and a curved stepped parting surface with a 35° inclination in the vertical direction. The curved stepped parting surface concentrates the bosses on the outer surface of the casting in the forming areas of the left lower half mold (2) and the right lower half mold (6). The mold body also includes a first movable block (3), a second movable block (7), a base plate (4), and an inner sand core (8) composed of resin-silica composite cores. The base plate (4) and the inner sand core (8) are positioned by a positioning structure. The positioning structure includes a positioning core head set at the bottom of the inner sand core (8) and a corresponding positioning groove on the base plate (4). The positioning groove is provided with a positioning pin. The clearance fit tolerance between the positioning pin and the pin hole on the inner sand core (8) is ±0.5mm. The mold body parting surface is equipped with a three-level positioning system, including four sets of Φ20mm tapered guide pillars arranged on the main parting surface, four sets of Φ20mm tapered guide pillars set on the curved stepped surface, and the installation, positioning and locking structure of the first movable block (3) and the second movable block (7).

2. The multi-positioning stepped parting low-pressure casting mold according to claim 1, characterized in that: The step height difference of the curved stepped parting surface is 5-10mm, and the horizontal distance between adjacent steps is 15-25mm. The curvature radius of the curved stepped parting surface is 1000-1500mm. The limiting effect of the curved stepped parting surface ensures that the positional error between the bosses is ≤±1mm.

3. The multi-positioning stepped parting low-pressure casting mold according to claim 1, characterized in that: In the three-level positioning system, the four sets of tapered guide pillars on the main parting surface are distributed at the four corners of the mold, and the fit clearance between the guide pillars and the guide sleeves is 0.05-0.1mm. The four sets of tapered guide pillars on the curved stepped surface are evenly distributed along the stepped direction, and the fit clearance between the guide pillars and the guide sleeves is 0.03-0.08mm.

4. The multi-positioning stepped parting low-pressure casting mold according to claim 1, characterized in that: The first movable block (3) and the second movable block (7) are slidably connected to the lower left half mold (2) and the lower right half mold (6) respectively through T-slots, and are locked to the lower left half mold (2) and the lower right half mold (6) by bolts. The positioning surfaces of the first movable block (3) and the second movable block (7) with the lower left half mold (2) and the lower right half mold (6) are inclined surfaces with an inclination of 1:

50.

5. A multi-positioning stepped parting low-pressure casting mold according to claim 1, characterized in that: The positioning structure between the base plate (4) and the inner sand core (8) achieves an assembly accuracy of ±1mm.

6. The multi-positioning stepped parting low-pressure casting mold according to claim 1, characterized in that: The mold body also includes an exhaust system, which includes an exhaust groove and an exhaust riser located at the highest point of the casting. The exhaust groove is 3-5 mm wide and 0.2-0.5 mm deep, and the exhaust riser is 10-15 mm in diameter and 20-30 mm in height.

7. A multi-positioning stepped parting low-pressure casting mold according to claim 1, characterized in that: The mold also includes a longitudinally graded sprue system, which includes a main gating system, a transverse gating system, and an ingate system. The ingate system is divided into three levels: upper, middle, and lower. The upper ingate system is located 5-10 mm above the hot spot of the casting, the middle ingate system is located in the middle of the casting, and the lower ingate system is located at the bottom of the casting. The cross-sectional area ratio of the ingate system is 1:1.2:1.5.

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