Device and method for improving lifting stability of 3D printing sand core
By designing a device including a lifting ring, a movable rod, a connecting rod and a support rod, the sand core is fixed using ropes and a rotating shaft, and the sand core status is determined by judging the buzzer alarm and current adjustment components, the unstable sand core lifting of the sand core is solved. The problem has achieved efficient and stable lifting operation and product quality improvement.
Patent Information
- Application Number
- CN202411694025.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-25
- Publication Date
- 2025-02-25
AI Technical Summary
The prior art has problems such as inconvenient operation, difficult to fix and easy to slide when lifting 3D printed sand cores, which leads to the sand core being often in an inclined state after being lifted, and the lifting operation is complicated, affecting the stability of product quality.
A device including a lifting ring, a movable rod, a connecting rod and a support rod is designed. The sleeves are driven away from each other through a rope and a rotating shaft, so that the rubber ball abuts on the side wall of the lifting chamber to fix the sand core, and passes through a buzzer alarm The current adjustment component determines the horizontal or upright state of the sand core and the swing amplitude.
The stable lifting of the sand core is achieved, the operation process is simplified, the work efficiency and product quality stability are improved, and the requirements for staff experience are reduced.
Smart Images
Figure CN119503638A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of sand casting technology, and in particular relates to a device and method for improving the hoisting stability of a 3D printed sand core. Background Art
[0002] Sand casting is a widely used process in casting production. It uses foundry sand and sand binder as basic raw materials, and produces steel, iron and most non-ferrous alloy castings by compacting them into molds. The sand cores of sand casting need to be hoisted during the process flow and when the core is assembled and placed. Generally, the sand cores are required to be stable after being hoisted, especially when the core is assembled and placed, the sand cores must be in a horizontal or upright state, otherwise the sand cores cannot be accurately lowered to the core seat mating surface, resulting in core placement failure, which seriously affects the cavity size.
[0003] In actual production life, when lifting the sand core, the workers use cloth ropes to bundle the sand cores, and then tie the cloth ropes that bundle the sand cores to the crane hook, and lift the sand cores by moving the crane.
[0004] The existing sand core lifting method has the following shortcomings:
[0005] 1. Most sand cores are usually irregular in shape, and it is inconvenient and difficult to fix them when they are tied with cloth ropes. They are easy to slip after being tied. In addition, it is difficult to hang the cloth ropes symmetrically on both sides of the center of gravity because the naked eye cannot find the exact center of gravity. As a result, the sand cores are often in a tilted state after being lifted. This requires experienced masters to constantly adjust the position of the cloth ropes to make them horizontal or upright. The operation is more cumbersome, and the lifting operation methods are not uniform, resulting in uneven product quality and the inability to guarantee the quality stability of mass production.
[0006] 2. The bundling of sand cores is done manually, which has low work efficiency. The quality of bundling depends on the experience accumulated by the staff, which places high demands on the staff.
[0007] 3. During lifting, the sand core often swings due to the unstable moving speed of the crane or other lifting devices and other factors. If the swing amplitude is small, it is difficult to observe. As a result, it is difficult to judge whether the sand core can be directly closed after it moves to the top of the lower mold. The staff needs to go to the sand core to confirm whether the swing amplitude can be closed, which affects the work efficiency. Summary of the invention
[0008] The purpose of the present invention is to provide a device and method for improving the lifting stability of 3D printed sand cores in response to the problems raised in the above background technology.
[0009] To achieve the above object, the present invention adopts the following technical solution: a device for improving the hoisting stability of 3D printed sand cores, comprising:
[0010] A lifting ring, a movable rod is provided below the lifting ring, a connecting rod is provided below the movable rod, the bottom end of the movable rod is slidably connected in the connecting rod, a supporting rod is fixed at the bottom of the connecting rod, a buzzer alarm is provided on the side wall of the connecting rod, and the buzzer alarm is electrically connected to an external power supply.
[0011] Furthermore, a limit plate is fixed at the bottom end of the movable rod, a first cavity is opened at the top end of the connecting rod, the limit plate is slidably connected in the first cavity, and a first spring is sleeved on the movable rod between the limit plate and the end of the first cavity.
[0012] Furthermore, a second cavity is opened in the middle of the support rod, and two annular plates are fixed in the second cavity. The two annular plates are rotatably connected with a rotating shaft through a torsion spring. Two ends of the rotating shaft are provided with two sections of external threads with opposite spiral directions. The rotating shaft is provided with a driving component for driving the rotating shaft to rotate.
[0013] Furthermore, the driving assembly includes a wire reel fixed to the middle of the rotating shaft, a rope is wound on the wire reel, a through hole is opened on the connecting rod, and one end of the rope passes through the through hole and is fixed on the limiting plate.
[0014] Furthermore, a fixing assembly is provided at both ends of the support rod, and the fixing assembly includes two sleeves slidably connected to the two ends of the support rod, one end of the sleeve extends into the second cavity, and a nut is fixed to the end of the sleeve in the second cavity, and the internal thread of the nut cooperates with the external thread on the rotating shaft, and a support block is fixed to the end of the sleeve away from the support rod.
[0015] Furthermore, three evenly distributed third cavities are opened on the support block, and three extrusion rods are slidably connected to the support block. One end of the extrusion rod extends into the third cavity, and a baffle is fixed to the end of the extrusion rod in the third cavity. A second spring is sleeved on the part of the extrusion rod in the third cavity, and both ends of the second spring are fixedly connected to the baffle and the side wall of the third cavity respectively, and a rubber ball is fixed to the end of the extrusion rod outside the third cavity.
[0016] Furthermore, a control switch is provided between the baffle and the side wall of the third cavity, and the control switch includes a first conductive sheet and a second conductive sheet respectively fixed on the side wall of the third cavity and the baffle, and six of the control switches are electrically connected to an external power supply in series.
[0017] Furthermore, a fourth cavity is opened on the connecting rod, and a current regulating component is arranged in the fourth cavity, and the current regulating component includes two circular plates slidably connected in the fourth cavity, an insulating porcelain cylinder is fixed between the two circular plates, and a resistance wire is wound on the insulating porcelain cylinder, a third spring is fixed between the bottom of the fourth cavity and the circular plate below, an adjusting plate is fixed on the side wall of the fourth cavity, and the adjusting plate is slidably connected to the resistance wire, and first binding posts are arranged on the top of the resistance wire and the adjusting plate, and the two first binding posts are electrically connected to an external power supply.
[0018] The present invention also provides a method for improving the hoisting stability of a 3D printed sand core, comprising the following steps:
[0019] S1. Design a suitable lifting cavity in the sand core according to the size of the support rod;
[0020] S2. Insert the support rod vertically into the bottom of the lifting cavity, and then rotate the support rod 90°;
[0021] S3. Slowly pull the lifting ring upwards to make the rubber ball contact the side wall of the lifting chamber, and adjust the position of the sand core until the buzzer alarm sounds an alarm;
[0022] S4, lift the sand core to the top of the lower mold;
[0023] S5, waiting for the sound fluctuation of the buzzer alarm to decrease to within an acceptable fluctuation range before closing the box.
[0024] Compared with the prior art, the advantages of the present invention are:
[0025] 1. The present invention sets a fixing component, and drives the rotating shaft to rotate by the rope moving upward relative to the movable rod, and further drives the two sleeves to move away from each other, so that the rubber ball abuts against the side wall of the lifting cavity to fix the sand core. The operation is simple and the work efficiency is high. The original method of tying with ropes and then constantly adjusting the position is abandoned, making the operation more convenient and simple, and standardizing the operation method, thereby improving the quality stability of mass production.
[0026] 2. The present invention provides a buzzer alarm, and whether the sand core is in a horizontal or vertical state can be accurately determined by whether the buzzer alarm sounds an alarm, which requires relatively low work experience of the staff.
[0027] 3. The present invention provides a current regulating component. If the sand core swings during lifting, the current passing through the buzzer alarm will change, thereby causing the sound of the buzzer alarm to fluctuate. The greater the swing amplitude of the sand core, the greater the fluctuation of the sound of the buzzer alarm. In this way, it is possible to accurately judge whether the sand core is swinging and the swing amplitude based on the sound of the buzzer alarm, and then determine whether the box can be closed. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 It is a schematic diagram of the overall structure of a device provided by the present invention for improving the hoisting stability of a 3D printing sand core;
[0029] Figure 2 It is a schematic diagram of the overall internal structure of a device provided by the present invention for improving the hoisting stability of a 3D printed sand core;
[0030] Figure 3 yes Figure 2 Enlarged view of point A in the middle;
[0031] Figure 4 yes Figure 2 Enlarged view of point B in the middle;
[0032] Figure 5 It is a schematic diagram of the internal structure of a support rod of a device for improving the hoisting stability of a 3D printing sand core provided by the present invention;
[0033] Figure 6 yes Figure 5 Enlarged view of point C in the middle;
[0034] Figure 7 It is a schematic diagram of the coordination structure of a resistance wire and an adjustment sheet of a device for improving the hoisting stability of a 3D printing sand core provided by the present invention;
[0035] Figure 8 The present invention provides a flow chart of a method for improving the hoisting stability of a 3D printed sand core.
[0036] In the figure, 1 lifting ring;
[0037] 2 movable rod, 21 limiting plate, 22 first spring;
[0038] 3 connecting rod, 30 buzzer alarm, 31 first cavity, 32 through hole, 33 fourth cavity;
[0039] 4 support rod, 41 second cavity, 42 annular plate, 43 rotating shaft, 431 external thread, 44 reel, 45 rope;
[0040] 51 sleeve, 52 nut, 53 support block, 531 third cavity, 532 extrusion rod, 533 baffle, 534 second spring, 535 rubber ball, 5311 first conductive sheet, 5331 second conductive sheet;
[0041] 61 circular plate, 62 insulating porcelain cylinder, 63 resistance wire, 64 third spring, 65 adjusting sheet. DETAILED DESCRIPTION
[0042] The following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.
[0043] like Figure 1-Figure 7 As shown, a device for improving the lifting stability of a 3D printed sand core comprises a lifting ring 1, a movable rod 2 is arranged below the lifting ring 1, a connecting rod 3 is arranged below the movable rod 2, the bottom end of the movable rod 2 is slidably connected to the connecting rod 3, a limiting plate 21 is fixed to the bottom end of the movable rod 2, a first cavity 31 is opened at the top of the connecting rod 3, the limiting plate 21 is slidably connected to the first cavity 31, a first spring 22 is sleeved on the movable rod 21 between the limiting plate 21 and the end of the first cavity 31, a supporting rod 4 is fixed to the bottom of the connecting rod 3, when the supporting rod 4 is idle, pulling the lifting ring 1 upward will directly drive the supporting rod 4 to move upward, after the supporting rod 4 is inserted into the sand core and fixes the sand core, pulling the lifting ring 1 upward will first drive the limiting plate 21 to compress the first spring 22 and move it upward, and only when the elastic force of the first spring 22 is the same as the weight it bears will it drive the supporting rod 4 to move upward, a buzzer alarm 30 is arranged on the side wall of the connecting rod 3, and the buzzer alarm 30 is electrically connected to the external power supply.
[0044] A second cavity 41 is provided in the middle of the support rod 4, and two annular plates 42 are fixed in the second cavity 41. A rotating shaft 43 is rotatably connected to the two annular plates 42 through a torsion spring. Two ends of the rotating shaft 43 are provided with two sections of external threads 431 with opposite spiral directions. The rotating shaft 43 is provided with a driving component for driving the rotating shaft 43 to rotate. The driving component includes a reel 44 fixed in the middle of the rotating shaft 43, and a rope 45 is wound around the reel 44. A through hole 32 is provided in the connecting rod 3, and one end of the rope 45 passes through the through hole 32 and is fixed to the limiting plate 21. When the limiting plate 21 moves upward relative to the connecting rod 3, the rope 45 is pulled, thereby driving the rotating shaft 43 to rotate and compressing the torsion spring.
[0045] Both ends of the support rod 4 are provided with fixing components, which include two sleeves 51 slidably connected to the two ends of the support rod 4, one end of the sleeve 51 extends into the second cavity 41, and a nut 52 is fixed to the end of the sleeve 51 in the second cavity 41, and the internal thread of the nut 52 is threadedly matched with the external thread 431 on the rotating shaft 43. When the rope 45 moves upward relative to the movable rod 3 to drive the rotating shaft 43 to rotate, the two sleeves 51 move away from each other under the action of thread matching, and a support block 53 is fixed to the end of the sleeve 51 away from the support rod 4, and three evenly distributed third cavities 531 are opened on the support block 53, and three extrusion rods 532 are slidably connected to the support block 53. The end of the extrusion rod 532 extends into the third cavity 531, the end of the extrusion rod 532 in the third cavity 531 is fixed with a baffle 533, the part of the extrusion rod 532 in the third cavity 531 is sleeved with a second spring 534, the two ends of the second spring 534 are respectively fixedly connected to the baffle 533 and the side wall of the third cavity 531, a rubber ball 535 is fixed to the end of the extrusion rod 532 outside the third cavity 531, a control switch is provided between the baffle 533 and the side wall of the third cavity 531, the control switch includes a first conductive sheet 5311 and a second conductive sheet 5331 respectively fixed on the side wall of the third cavity 531 and the baffle 533, and the six control switches are electrically connected to the external power supply in a series manner.
[0046] During operation, the support rod 4 is vertically inserted into the lifting cavity and rotated 90°, and then the lifting ring 1 is slowly pulled upward. Under the action of the gravity of the sand core, the movable rod 3 drives the limit plate 21 to move upward relative to the movable rod 3, thereby driving the rope 45 to move upward. The upward movement of the rope 45 drives the rotating shaft 43 to rotate, further driving the two sleeves 51 away from each other, so that the rubber ball 535 abuts against the side wall of the lifting cavity to fix the sand core.
[0047] After the rubber ball 535 abuts against the side wall of the lifting chamber, continuing to pull the lifting ring 1 upwards will make the first conductive sheet 5311 and the second conductive sheet 5331 approach each other until they touch each other. Since the three rubber balls 535 on the same support block 53 are in the same vertical plane, if all the first conductive sheets 5311 are in contact with their corresponding second conductive sheets 5331, it means that the side wall of the lifting chamber is in a vertical state. At this time, the Fengming alarm 30 will sound an alarm when it is powered on, and you can continue to pull to lift the sand core. If the buzzer alarm 30 does not sound, it means that at least one rubber ball 535 is not in contact with the side wall of the lifting chamber, which means that the side wall of the lifting chamber is not in a vertical state and the position of the sand core needs to be adjusted.
[0048] A fourth cavity 33 is opened on the connecting rod 3, and a current regulating component is arranged in the fourth cavity 33. The current regulating component includes two circular plates 61 slidably connected in the fourth cavity 33, an insulating porcelain cylinder 62 is fixed between the two circular plates 61, and a resistance wire 63 is wound on the insulating porcelain cylinder 62. A third spring 64 is fixed between the bottom of the fourth cavity 33 and the circular plate 61 below, and an adjusting plate 65 is fixed on the side wall of the fourth cavity 33. The adjusting plate 65 is slidably connected to the resistance wire 63. First terminals are arranged on the top of the resistance wire 63 and the adjusting plate 65, and the two first terminals are electrically connected to the external power supply.
[0049] If the sand core swings during hoisting, the insulating porcelain tube 62 begins to move toward the third spring 64 under the action of centrifugal force. When the sand core swings to the lowest position, the centrifugal force of the insulating porcelain tube 62 is the largest, the compression degree of the third spring 64 is the largest, and the relative movement stroke of the insulating porcelain tube 62 and the resistance wire 63 toward the third spring 64 is the largest. At this time, the effective resistance of the resistance wire 63 is the smallest, so that the current passing through the buzzer alarm 30 is the largest, and the sound of the buzzer alarm 30 is also the largest. In addition, the larger the swing amplitude of the sand core, the larger the maximum sound of the buzzer alarm 30. When the sand core leaves the lowest position of the swing, the centrifugal force of the insulating porcelain tube 62 gradually decreases, and the sound of the buzzer alarm 30 also gradually decreases. Accordingly, whether the sand core is swinging and the amplitude of the swing can be judged according to the sound of the buzzer alarm 30. When the sand core moves to the top of the lower mold, if the sound of the buzzer alarm 30 is stable, it means that the sand core is not swinging and the box can be directly closed. If the sound of the buzzer alarm 30 fluctuates, it means that the sand core is swinging. Whether the swing range is within the acceptable range can be judged according to the size of the maximum sound to determine whether the box can be closed.
[0050] like Figure 8 As shown, the present invention also provides a method for improving the hoisting stability of a 3D printed sand core, comprising the following steps:
[0051] S1. Design a suitable lifting cavity in the sand core according to the size of the support rod 4;
[0052] S2, vertically insert the support rod 4 into the bottom of the lifting cavity, and then rotate the support rod 4 90°;
[0053] S3, slowly pull the lifting ring 1 upwards to make the rubber ball 535 abut against the side wall of the lifting chamber, and the buzzer alarm 30 sounds an alarm when the position of the sand core is adjusted;
[0054] S4, lift the sand core to the top of the lower mold;
[0055] S5, waiting for the sound fluctuation of the buzzer alarm 30 to decrease to within an acceptable fluctuation range before closing the box.
[0056] The working principle of the present invention is as follows:
[0057] During operation, the support rod 4 is vertically inserted into the lifting cavity and rotated 90°, and then the lifting ring 1 is slowly pulled upward. Under the action of the gravity of the sand core, the movable rod 3 drives the limit plate 21 to move upward relative to the movable rod 3, thereby driving the rope 45 to move upward. The upward movement of the rope 45 drives the rotating shaft 43 to rotate, further driving the two sleeves 51 away from each other, so that the rubber ball 535 abuts against the side wall of the lifting cavity to fix the sand core. The operation is simple and the work efficiency is high.
[0058] After the rubber ball 535 abuts against the side wall of the lifting chamber, continuing to pull the lifting ring 1 upwards will make the first conductive sheet 5311 and the second conductive sheet 5331 approach each other until they touch each other. Since the three rubber balls 535 on the same support block 53 are in the same vertical plane, if all the first conductive sheets 5311 are in contact with their corresponding second conductive sheets 5331, it means that the side wall of the lifting chamber is in a vertical state. At this time, the Fengming alarm 30 will sound an alarm when it is powered on, and you can continue to pull to lift the sand core. If the buzzer alarm 30 does not sound, it means that at least one rubber ball 535 is not in contact with the side wall of the lifting chamber, indicating that the side wall of the lifting chamber is not in a vertical state, and the position of the sand core needs to be adjusted. The Fengming alarm 30 can accurately determine whether the sand core is in a vertical or horizontal state by whether the alarm is sounded, and the work experience required of the staff is relatively low.
[0059] If the sand core swings during hoisting, the insulating porcelain cylinder 62 begins to move toward the direction close to the third spring 64 under the action of centrifugal force. When the sand core swings to the lowest position, the centrifugal force of the insulating porcelain cylinder 62 is the largest, the compression degree of the third spring 64 is the largest, and the relative insulating porcelain cylinder 62 and the resistance wire 63 move toward the direction close to the third spring 64 The stroke is the largest, and the effective resistance of the resistance wire 63 is the smallest at this time, so that the current passing through the buzzer alarm 30 is the largest, and the sound of the buzzer alarm 30 is also the largest, and the greater the swing amplitude of the sand core, the greater the maximum sound of the buzzer alarm 30. When the sand core leaves the lowest swing position, the centrifugal force of the insulating porcelain cylinder 62 gradually decreases, and the sound of the buzzer alarm 30 gradually decreases. Gradually decrease, and thus, whether the sand core is swinging and the amplitude of the swing can be judged according to the sound of the buzzer alarm 30. When the sand core moves to the top of the lower mold, if the sound of the buzzer alarm 30 is stable, it means that the sand core is not swinging and the box can be directly closed. If the sound of the buzzer alarm 30 fluctuates, it means that the sand core is swinging, and whether the swing range is within an acceptable range can be judged according to the size of the maximum sound of the buzzer alarm 30 to judge whether the box can be closed. There is no need for manual observation, which improves work efficiency. The present invention abandons the original method of tying with ropes and then constantly adjusting the position, making the operation more convenient and simple, and standardizing the operation method, thereby improving the quality stability of mass production.
[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims
1. A device for improving the hoisting stability of 3D printed sand cores, characterized in that: include: A lifting ring (1), a movable rod (2) is provided below the lifting ring (1), a connecting rod (3) is provided below the movable rod (2), the bottom end of the movable rod (2) is slidably connected in the connecting rod (3), a supporting rod (4) is fixed at the bottom of the connecting rod (3), a buzzer alarm (30) is provided on the side wall of the connecting rod (3), and the buzzer alarm (30) is electrically connected to an external power supply.
2. The device for improving the hoisting stability of 3D printed sand cores according to claim 1, characterized in that: A limiting plate (21) is fixed at the bottom end of the movable rod (2), a first cavity (31) is formed at the top end of the connecting rod (3), the limiting plate (21) is slidably connected in the first cavity (31), and a first spring (22) is sleeved on the movable rod (2) 1 between the limiting plate (21) and the end of the first cavity (31).
3. The device for improving the hoisting stability of 3D printing sand cores according to claim 2, characterized in that: A second cavity (41) is provided in the middle of the support rod (4), two annular plates (42) are fixed in the second cavity (41), a rotating shaft (43) is rotatably connected to the two annular plates (42) via a torsion spring, two ends of the rotating shaft (43) are provided with two sections of external threads (431) with opposite spiral directions, and a driving component for driving the rotating shaft (43) to rotate is provided on the rotating shaft (43).
4. The device for improving the hoisting stability of 3D printing sand cores according to claim 3, characterized in that: The driving assembly comprises a wire reel (44) fixed to the middle of the rotating shaft (43), a rope (45) is wound around the wire reel (44), a through hole (32) is formed on the connecting rod (3), and one end of the rope (45) passes through the through hole (32) and is fixed to the limiting plate (21).
5. The device for improving the hoisting stability of 3D printing sand cores according to claim 4, characterized in that: A fixing assembly is provided at both ends of the support rod (4), and the fixing assembly includes two sleeves (51) slidably connected to the two ends of the support rod (4), one end of the sleeve (51) extends into the second cavity (41), a nut (52) is fixed to the end of the sleeve (51) in the second cavity (41), the internal thread of the nut (52) is threadably matched with the external thread (431) on the rotating shaft (43), and a support block (53) is fixed to the end of the sleeve (51) away from the support rod (4).
6. The device for improving the hoisting stability of 3D printing sand cores according to claim 5, characterized in that: The support block (53) is provided with three evenly distributed third cavities (531), and three extrusion rods (532) are slidably connected to the support block (53), one end of the extrusion rod (532) extends into the third cavity (531), a baffle (533) is fixed to the end of the extrusion rod (532) in the third cavity (531), a second spring (534) is sleeved on the part of the extrusion rod (532) in the third cavity (531), two ends of the second spring (534) are respectively fixedly connected to the baffle (533) and the side wall of the third cavity (531), and a rubber ball (535) is fixed to the end of the extrusion rod (532) outside the third cavity (531).
7. The device for improving the hoisting stability of 3D printing sand cores according to claim 6, characterized in that: A control switch is provided between the baffle (533) and the side wall of the third cavity (531), and the control switch comprises a first conductive sheet (5311) and a second conductive sheet (5331) respectively fixed on the side wall of the third cavity (531) and the baffle (533), and six of the control switches are electrically connected to an external power supply in a series manner.
8. The device for improving the hoisting stability of 3D printing sand cores according to claim 1, characterized in that: A fourth cavity (33) is provided on the connecting rod (3), and a current regulating component is provided in the fourth cavity (33). The current regulating component comprises two circular plates (61) slidably connected in the fourth cavity (33), an insulating porcelain cylinder (62) is fixed between the two circular plates (61), and a resistance wire (63) is wound on the insulating porcelain cylinder (62), a third spring (64) is fixed between the bottom of the fourth cavity (33) and the circular plate (61) below, an regulating plate (65) is fixed on the side wall of the fourth cavity (33), and the regulating plate (65) is slidably connected to the resistance wire (63), and the top of the resistance wire (63) and the regulating plate (65) are both provided with terminal blocks, and the circuit connection mode of the current regulating component and the control switch is series connection.
9. A method for improving the hoisting stability of 3D printed sand cores applied to claims 1-8, characterized in that: The following steps are involved: S1. Designing a suitable lifting cavity in the sand core according to the size of the support rod (4); S2, vertically insert the support rod (4) into the bottom of the lifting cavity, and then rotate the support rod (4) 90°; S3, slowly pull the lifting ring (1) upwards to make the rubber ball (535) abut against the side wall of the lifting chamber, and adjust the position of the sand core so that the buzzer alarm (30) sounds an alarm; S4, lift the sand core to the top of the lower mold; S5, waiting for the sound fluctuation of the buzzer alarm (30) to decrease to within an acceptable fluctuation range before closing the box.