A robotic shoulder joint housing injection molding process

Abstract

This invention discloses a casting process for a robot shoulder joint shell, comprising: S1: preparing an upper sand box and a lower sand box, and heating the upper and lower sand boxes; S2: placing a metal model into the lower sand box, and using a compressed air sand injection device to inject coated sand through the sand injection hole into the gap between the molding cavity and the metal model to form a coated sand layer; S3: heating the molten metal to a molten state, and pouring it into the molding cavity through a gating system; S4: after pouring, cooling the mold to allow the casting liquid to solidify in the molding cavity to form a shell casting. This invention can obtain a robot shoulder joint with a smooth surface and high strength.

Description

Technical Field

[0001] This invention relates to a casting process, and more particularly to a casting process for a robot shoulder joint shell. Background Technology

[0002] Industrial robots, collaborative robots, and humanoid robots have been widely used in intelligent manufacturing, medical rehabilitation, and social services. The shoulder joint shell of a robot is a complex, thin-walled precision casting, and its dimensional accuracy directly affects the joint's motion accuracy and assembly compatibility. Currently, the mainstream manufacturing processes for robot joint shells include precision die casting, iron mold sand casting, and injection molding.

[0003] Iron mold sand casting uses a metal mold as its "outer shell," with a thin layer of thermosetting coated sand covering its inner wall to form a rigid and high-precision mold. It combines the advantages of both metal mold casting and sand casting. However, in the production of castings with complex cavities, problems such as poor slag avoidance and untimely feeding are more prominent, making it difficult to control the dimensional accuracy of the product within ±0.2mm. The process yield is less than 60%, which seriously restricts the industrialization development. Existing methods to reduce the occurrence of microporosity include setting multiple vent holes inside the mold and hammering the outside of the mold. However, complex structures, protrusions that are prone to gas accumulation, and deep cavities can still easily lead to gas stagnation, resulting in fine pores on the surface of the casting, which affects its rigidity and flexibility.

[0004] Therefore, this case aims to provide a casting process for the shell of a robot shoulder joint, which can perform venting in different ways at different stages of casting, so as to quickly remove the gas brought in during casting and prevent it from being carried into the corners by the newly entered molten liquid, thereby obtaining a robot shoulder joint with a smooth surface and high strength. This is the research objective of this case. Summary of the Invention

[0005] This invention provides a casting molding process for the shell of a robot shoulder joint, which can effectively solve the above-mentioned problems.

[0006] This invention is implemented as follows: A casting process for a robot shoulder joint shell includes: S1: Prepare upper and lower sand boxes with cavity contours that match the shape of the robot shoulder joint shell, and heat the upper and lower sand boxes. S2: Place the metal model into the lower sand box and let the upper sand box and the lower sand box close together to form a molding cavity. Use a compressed air sand injection device to inject the coating sand through the sand injection hole into the gap between the molding cavity and the metal model to form a coating sand layer. After opening the mold, take out the metal model and close the mold again. S3: Heat the molten metal to a molten state and pour it into the forming cavity through a gating system; S31: When the level of the pouring liquid is below the movable passage plate of the lower sand box, pouring is carried out at the first pouring speed. At this time, the hot air in the molding cavity is stored in the temporary chamber through the movable exhaust hole via the movable passage plate by the suction device, so that negative pressure is formed in the molding cavity. S32: When the surface of the pouring liquid is close to the movable plate, pouring is carried out at the second pouring speed. At this time, the pressurization device pushes the movable fitting part outward through the temporary chamber to block the movable plate. At the same time, the molding cavity is under positive pressure and the gas in the molten liquid is pushed into the upper exhaust hole and the movable exhaust hole. S33: Perform shrinkage filling pouring at the third pouring speed until the cavity is completely filled; S4: After pouring, the mold is cooled to allow the pouring liquid to solidify in the molding cavity and form a shell casting.

[0007] As a further improvement, a molding die for molding is also included, the molding die comprising: The mold body includes an upper sand box and a lower sand box that are configured to fit together, and the upper sand box and the lower sand box form two molding cavities after they fit together. The injection structure includes a gating and riser located in the middle of the upper sand box and communicating with two molding cavities, wherein the upper sand box is provided with at least one sand injection hole; The multi-end venting structure includes an upper vent hole located in the middle of the top of the upper sand box and a movable vent hole located on the outer edge of the top of the upper sand box. The top of the movable vent hole extends upward and is connected to a double-ended connecting pipe that penetrates the upper sand box. One end of the double-ended connecting pipe is connected to a pressurizing device, and the other end is connected to a suction device. Both the pressurizing device and the suction device are connected to a temporary chamber. The pressurizing device is movably connected to at least one upper vent hole. The lower sand box is equipped with a movable venting component. The movable venting component includes a movable through plate located on the inner wall of the lower sand box. A movable fitting component that can move within the lower sand box is provided on the side of the movable through plate closest to the interior of the lower sand box. When the pouring liquid level is below the movable through plate, the movable fitting component is spaced apart from the movable through plate. When the pouring liquid level is close to the movable through plate, the movable fitting component blocks the movable through plate.

[0008] As a further improvement, an L-shaped hole is provided in the lower sand box, and the movable through plate is located at the opening of one end of the short shaft of the L-shaped hole and is flush with the inner wall of the lower sand box. Several flow holes are provided on the movable through plate.

[0009] As a further improvement, a clamping cylinder is provided at the opening of the long shaft of the L-shaped hole, and an inner shrinking cylinder is provided at the bottom opening of the movable vent hole, with the inner shrinking cylinder embedded inside the clamping cylinder.

[0010] As a further improvement, a connecting groove is provided on the side of the L-shaped hole away from the short axis, which extends through the outer side of the lower sand box. A movable fitting is inserted into the connecting groove, and the outer side of the movable fitting is locked to the outer side of the lower sand box by an outer plate.

[0011] As a further improvement, the movable mating part includes a fixing part that connects to the outer plate, and the other end of the fixing part is connected to an adjusting spring, which has a sealing part that mates with the movable through plate.

[0012] As a further improvement, the sealing part includes a movable baffle connected to an adjusting spring, and a plurality of sealing posts corresponding to the flow holes of the movable through plate are fixedly connected to the movable baffle.

[0013] As a further improvement, the movable mating part is located below the centerline of the molding cavity.

[0014] As a further improvement, the first pouring speed is 0.4 to 0.8 kg / s, the second pouring speed is 0.8 to 1.2 kg / s, and the third pouring speed is 0.2 to 0.5 kg / s.

[0015] As a further improvement, the vacuum degree inside the molding cavity is -0.06 to -0.09 MPa.

[0016] The beneficial effects of this invention are: During the casting process, the gas contained in the casting liquid and some air carried along with it as it flows downwards will simultaneously enter the molding cavity, resulting in shrinkage cavities or micro-pores on the delicate robot joints. Therefore, this invention achieves changes in air pressure within the molding cavity through multi-stage casting. First, it has a conventional upper vent 31, which allows for normal venting at the top of the cavity. Furthermore, through the lower movable vent 41 and movable vent 50, hot air in the molding cavity can be extracted in the early stages of casting, creating a weak negative pressure environment within the molding cavity. As the external pressure decreases, bubbles in the molten metal are more likely to expand, rise, and burst and be discharged. As the casting process progresses, the height of the casting liquid gradually exceeds the position of the movable vent 41 and movable vent 50. The movable vent 50 then blocks the movable vent 41 to prevent the casting liquid from flowing out from this position and forming burrs. In the latter half of the pouring process, the pressurizing device 43 is connected to at least one upper vent 31. Positive pressure is applied to the forming cavity in the latter half of the pouring process. Since the gas introduced at this time is the gas extracted from the forming cavity in the previous stage, the temperature is just right. This not only allows the molten metal to fluctuate and squeeze out the air bubbles in the molten metal, but also fully compresses the molten metal into the deep cavity area. The gas after the action will be discharged through the upper vent 31 that is not connected to the pressurizing device 43, thus achieving the effect of negative pressure in the first stage and positive pressure in the second stage. Moreover, the gas used is the original cavity gas, which is more stable than the later introduction of inert gas alone, and is more beneficial to the molding of the mold. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a flow chart of the molding process of the present invention.

[0019] Figure 2 This is a schematic diagram of the structure of the present invention.

[0020] Figure 3 This is the present invention. Figure 2 Top view.

[0021] Figure 4 This is the present invention. Figure 3 Cross-sectional view at point AA.

[0022] Figure 5 This is the present invention. Figure 3 Cross-sectional view at point BB.

[0023] Figure 6 This is a schematic diagram of the structure of the lower sand box of the present invention.

[0024] Figure 7 This is a schematic diagram of the molding die of the present invention.

[0025] In the picture: Mold body 10, upper sand box 11, lower sand box 12, clamping cylinder 121, outer plate 13, gating and riser 21, connecting section 211, adjusting section 212, inner connecting area 2121, outer expansion ring 2122, adjusting block 2123, connecting pipe 2124, funnel section 213, sand injection hole 22, upper vent hole 31, movable vent hole 41, inner shrink cylinder 411, double-ended connecting pipe 42, pressurizing device 43, suction device 44, temporary chamber 45, movable venting component 50, movable through plate 51, movable mating component 52, fixing part 521, adjusting spring 522, sealing part 523, movable baffle 5231, sealing post 5232. Detailed Implementation

[0026] All embodiments of the present invention are intended to fall within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0027] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating that the purpose, technical solution, and advantages of the method are clearer. The technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort indicate or imply the relative importance of the indicated technical features. Therefore, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0028] Reference Figure 1 As shown, a casting process for a robot shoulder joint shell includes: S1: Prepare upper sand box 11 and lower sand box 12 with cavity contours that match the shape of the robot shoulder joint shell, and heat the upper sand box 11 and lower sand box 12. S2: Place the metal model into the lower sand box 12, and let the upper sand box 11 and the lower sand box 12 close together to form a molding cavity. Use a compressed air sand injection device to inject the coating sand through the sand injection hole 22 into the gap between the molding cavity and the metal model to form a coating sand layer. After opening the mold, take out the metal model and close the mold again. S3: Heat the molten metal to a molten state and pour it into the forming cavity through the riser 21; S31: When the level of the pouring liquid is below the movable passage plate 51 of the lower sand box 12, pouring is carried out at the first pouring speed. At this time, the hot air in the molding cavity is stored in the temporary chamber 45 through the movable exhaust hole 41 via the movable passage plate 51 by the suction device 44, so that negative pressure is formed in the molding cavity. S32: When the surface of the pouring liquid is close to the movable through plate 51, pouring is carried out at the second pouring speed. At this time, the pressurizing device 43 pushes the temporary chamber 45 to push the movable mating part 52 outward to block the movable through plate 51. At the same time, the molding cavity is under positive pressure and the gas in the molten liquid rushing to the bottom corner of the molding cavity is injected into the upper exhaust hole 31 and the movable exhaust hole 41. S33: Perform shrinkage filling pouring at the third pouring speed until the cavity is completely filled; S4: After pouring, the mold is cooled to allow the pouring liquid to solidify in the molding cavity and form a shell casting.

[0029] Furthermore, the first pouring speed is 0.4–0.8 kg / s, the second pouring speed is 0.8–1.2 kg / s, and the third pouring speed is 0.2–0.5 kg / s.

[0030] Furthermore, the vacuum level inside the molding cavity is -0.06 to -0.09 MPa.

[0031] Reference Figures 2-7 As shown, the present invention also provides a casting mold for a robot shoulder joint shell, comprising: a mold body 10, including an upper sand box 11 and a lower sand box 12 that are configured to fit together, the upper sand box 11 and the lower sand box 12 forming two molding cavities after fitting together; a flow injection structure, including a gating gate 21 located in the middle of the upper sand box 11 and communicating with the two molding cavities, the upper sand box 11 having at least one sand injection hole 22; and a multi-end venting structure, including an upper venting hole 31 located in the middle of the top of the upper sand box 11 and a movable venting hole 41 located on the outer edge of the top of the upper sand box 11, the top of the movable venting hole 41 extending upward and connected to a double-ended connecting pipe 42 penetrating the upper sand box 11, one end of the double-ended connecting pipe 42 being connected to a pressurizing device. On the equipment 43, the other end of the double-ended connecting pipe 42 is connected to the suction device 44. The pressurizing device 43 and the suction device 44 are both connected to a temporary chamber 45. The pressurizing device 43 is movably connected to at least one upper exhaust port 31. The lower sand box 12 is provided with a movable exhaust component 50. The movable exhaust component 50 includes a movable through plate 51 disposed on the inner wall of the lower sand box 12. A movable mating component 52 that can move within the lower sand box 12 is disposed on the side of the movable through plate 51 near the inside of the lower sand box 12. When the pouring liquid level is below the movable through plate 51, the movable mating component 52 is spaced apart from the movable through plate 51. When the pouring liquid level is close to the movable through plate 51, the movable mating component 52 blocks the movable through plate 51.

[0032] During the casting process, the gas contained in the casting liquid and some air carried along with it during the downward flow simultaneously enter the molding cavity, causing shrinkage cavities or micro-pores on the delicate robot joints. Therefore, this embodiment uses a multi-end venting structure. First, it has a conventional upper vent 31 for normal venting at the top of the cavity. Second, through the lower movable vent 41 and movable vent 50, in the pre-casting stage, hot air is extracted from the molding cavity, creating a slight negative pressure environment. Due to the reduced external pressure, bubbles in the molten metal expand more easily, rise, and burst. As the casting process progresses, the height of the casting liquid gradually exceeds the movable vent 41 and movable vent 50. At position 50, the movable vent hole 41 is blocked by the movable vent 50 to prevent the casting liquid from flowing out from this position and forming burrs. In the second half of the casting: the pressurizing device 43 is connected to at least one upper vent hole 31. Positive pressure is applied to the forming cavity in the second half of the casting. Since the gas introduced at this time is the gas extracted from the forming cavity in the previous stage, the temperature is just right. It can not only make the molten metal fluctuate and squeeze out the air bubbles in the molten metal, but also fully squeeze the molten metal into the deep cavity area. The gas after the action will be discharged through the upper vent hole 31 that is not connected to the pressurizing device 43, thus obtaining the effect of negative pressure in the first stage and positive pressure in the second stage. Moreover, the gas used is the original cavity gas, which is more stable than the later introduction of inert gas alone, and is more beneficial to the molding of the mold.

[0033] Both the upper sand box 11 and the lower sand box 12 are equipped with sensors to detect the level of the pouring liquid, so that the pouring speed can be changed in real time according to the change of the liquid level, and the pouring speed can be adjusted in real time when the liquid inlet speed changes.

[0034] The booster device 43 is detachably connected to the upper exhaust port 31 via a pipeline, so it can be inserted under positive pressure and pulled out when negative pressure is applied.

[0035] The pouring process is divided into two stages: a slow initial stage and a slightly accelerated later stage. The slow initial stage occurs when the pouring liquid level is below the movable guide plate 51, while the accelerated later stage occurs when the pouring liquid level gradually approaches the movable guide plate 51, at which point the pouring liquid level is almost submerging the area of ​​the movable guide plate 51. When the pouring liquid level is below the movable guide plate 51, the suction device 44 pulls back the movable mating part 52, allowing the hot air in the molding cavity to pass through the movable guide plate 51 and be stored in the temporary chamber 45 through the movable exhaust hole 41, creating a negative pressure in the molding cavity. When the pouring liquid level approaches the movable guide plate 51, the pressurizing device 43 pumps the gas in the temporary chamber 45 into the upper exhaust hole 31 and the movable exhaust hole 41, causing the movable mating part 52 to push outward and block the movable guide plate 51. At the same time, the molding cavity is under positive pressure, causing the molten liquid to surge towards the bottom corner of the molding cavity.

[0036] Since the movement of the movable mating part 52 depends entirely on the direction of air movement in the molding cavity, an L-shaped hole is provided in the lower sand box 12 in this embodiment. The movable through plate 51 is located at the opening of one end of the short shaft of the L-shaped hole and is flush with the inner wall of the lower sand box 12. Several flow holes are provided on the movable through plate 51. During the negative pressure extraction process, since the movable through plate 51 is closer to the pouring surface, the air brought in during pouring will preferentially escape through the flow holes on the movable through plate 51 and the L-shaped hole. It will then be collected by the suction device 44 and stored in the temporary chamber 45 through the L-shaped hole. Furthermore, the smooth design of the movable through plate 51 and the molding cavity will not affect the joint shape after molding.

[0037] To ensure smooth gas flow between the upper sand box 11 and the lower sand box 12, a clamping cylinder 121 is provided at the opening of the long shaft of the L-shaped hole, and an inner shrinking cylinder 411 is provided at the bottom opening of the movable exhaust hole 41. The inner shrinking cylinder 411 is embedded inside the clamping cylinder 121, thereby ensuring the correspondence between the L-shaped hole and the movable exhaust hole 41, and thus ensuring the cooperation effect of the two sand boxes.

[0038] The movable fitting 52 is movably installed inside the L-shaped hole. To ensure its stability and maintainability, in this embodiment, a connecting groove is provided on the side of the L-shaped hole away from the short axis, which passes through the outer side of the lower sand box 12. The movable fitting 52 is inserted into the connecting groove. The outer side of the movable fitting 52 is locked to the outer side of the lower sand box 12 by an outer plate 13. Through the outer plate 13 that movably fits with the lower sand box 12, the outer plate 13 is locked between the upper sand box 11 and the lower sand box 12 after each mold closing, which not only achieves a fixing effect but also ensures the stability of the movable fitting 52.

[0039] The movable mating part 52 has two states, both of which are affected by gas. Specifically, the movable mating part 52 includes a fixing part 521 that connects to the outer plate 13. The other end of the fixing part 521 is connected to an adjusting spring 522. The adjusting spring 522 has a blocking part 523 that cooperates with the movable through plate 51. When subjected to positive pressure, since the fixing part 521 is in a fixed state, the adjusting spring 522 will be stretched, causing the blocking part 523 to be pushed out and block the movable through plate 51. When subjected to negative pressure, the blocking part 523 will slide towards one end of the fixing part 521, causing the adjusting spring 522 to contract.

[0040] When the sealing part 523 cooperates with the movable through plate 51, they are in a one-to-one correspondence. In this embodiment, the sealing part 523 includes a movable baffle 5231 connected to the adjusting spring 522. A plurality of blocking posts 5232 corresponding to the flow holes of the movable through plate 51 are fixed on the movable baffle 5231. So that when the sealing part 523 is subjected to positive pressure, the blocking posts 5232 can cooperate with the flow holes of the movable through plate 51 after the movable baffle 5231 slides.

[0041] In order to ensure that the air brought in by the pouring can be drawn away from the movable vent 41, the movable fitting 52 in this embodiment is located below the centerline of the molding cavity, so that the excited gas can be drawn away quickly, providing more gas storage for the temporary chamber 45.

[0042] When pouring liquid into the riser 21, it is necessary to maintain the continuity of pouring to avoid introducing more gas. However, since the speed of the pouring end and the pouring center point are sometimes uncertain, the riser 21 in this embodiment includes a connecting section 211 that cooperates with the upper sand box 11. The upper end of the connecting section 211 is connected to an adjusting section 212, and the upper end of the adjusting section 212 is connected to a funnel section 213. A temperature sensor is provided on the inner side of the funnel section 213. The height of the liquid level on the funnel section 213 can be detected by the temperature sensor, and the liquid inlet speed of the riser 21 can be adjusted according to the liquid level. In this embodiment, specifically, the adjusting section 212 includes an inner connecting area 2. 121. An outer expansion ring 2122 is provided on the outer side of the inner connecting area 2121. An adjusting block 2123 that can slide inward to the inner side of the inner connecting area 2121 is provided in the gap between the outer expansion ring 2122 and the inner connecting area 2121. The outer side of the outer expansion ring 2122 is connected to the pressurizing device 43 through a connecting pipe 2124 with a control valve. As can be seen from the figure, the adjusting block 2123 is tightened and fixed by a spring, so that it will only be pushed out during the process of gas pressurization by the pressurizing device 43. Under normal conditions, it will retract into the outer expansion ring 2122. Thus, when the liquid level in the funnel section 213 is too low, the adjusting block 2123 can be pushed out to ensure the liquid level in the funnel section 213 and avoid air mixing.

[0043] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A casting process for a robot shoulder joint shell, characterized in that, include: S1: Prepare an upper sand box (11) and a lower sand box (12) with cavity contours that match the shape of the robot shoulder joint shell, and heat the upper sand box (11) and the lower sand box (12); S2: Place the metal model into the lower sand box (12) and let the upper sand box (11) and the lower sand box (12) close together to form a molding cavity. Use a compressed air sand injection device to inject the coating sand through the sand injection hole (22) into the gap between the molding cavity and the metal model to form a coating sand layer. After opening the mold, take out the metal model and close the mold again. S3: Heat the molten metal to a molten state and pour it into the forming cavity through the riser (21); S31: When the level of the casting liquid is below the movable through plate (51) of the lower sand box (12), the casting is carried out at the first casting speed. At this time, the hot air in the molding cavity is stored in the temporary chamber (45) through the movable exhaust hole (41) via the suction device (44) through the movable through plate (51), so that the molding cavity forms a negative pressure. S32: When the surface of the pouring liquid is close to the movable through plate (51), pouring is carried out at the second pouring speed. At this time, the temporary chamber (45) is pushed outward by the pressurizing device (43) to block the movable through plate (51). At the same time, the molding cavity is under positive pressure and the gas in the molten liquid is pushed into the upper exhaust hole (31) and the movable exhaust hole (41) by the gas that surges to the bottom corner of the molding cavity. S33: Perform shrinkage filling pouring at the third pouring speed until the cavity is completely filled; S4: After pouring, the mold is cooled to allow the pouring liquid to solidify in the molding cavity and form a shell casting.

2. The casting process for a robot shoulder joint shell according to claim 1, characterized in that, It also includes a molding die for forming, the molding die comprising: The mold body (10) includes an upper sand box (11) and a lower sand box (12) that are configured to cooperate with each other. The upper sand box (11) and the lower sand box (12) form two molding cavities after they are fitted together. The injection structure includes a gating gate (21) located in the middle of the upper sand box (11) and communicating with two molding cavities. The upper sand box (11) is provided with at least one sand injection hole (22). The multi-end exhaust structure includes an upper exhaust port (31) located in the middle of the top of the upper sand box (11) and a movable exhaust port (41) located on the outer edge of the top of the upper sand box (11). The top of the movable exhaust port (41) extends upward and is connected to a double-ended connecting pipe (42) that penetrates the upper sand box (11). One end of the double-ended connecting pipe (42) is connected to a pressurizing device (43), and the other end of the double-ended connecting pipe (42) is connected to a suction device (44). The pressurizing device (43) and the suction device (44) are both connected to a temporary chamber (45). The pressurizing device (43) is connected to at least one upper exhaust port. The vent (31) is movably connected, and the interior of the lower sand box (12) is provided with a movable venting component (50). The movable venting component (50) includes a movable through plate (51) disposed on the inner wall of the lower sand box (12). The movable through plate (51) is provided with a movable fitting component (52) that can move inside the lower sand box (12) on the side near the interior of the lower sand box (12). When the pouring liquid level is below the movable through plate (51), the movable fitting component (52) is spaced apart from the movable through plate (51). When the pouring liquid level is close to the movable through plate (51), the movable fitting component (52) blocks the movable through plate (51).

3. The casting process for a robot shoulder joint shell according to claim 2, characterized in that, An L-shaped hole is provided in the lower sand box (12). The movable through plate (51) is located at the opening of one end of the short shaft of the L-shaped hole and is flush with the inner wall of the lower sand box (12). Several flow holes are provided on the movable through plate (51).

4. The casting process for a robot shoulder joint shell according to claim 3, characterized in that, A clamping cylinder (121) is provided at the opening of the long shaft of the L-shaped hole, and an inner shrinking cylinder (411) is provided at the bottom opening of the movable vent hole (41). The inner shrinking cylinder (411) is embedded in the inner side of the clamping cylinder (121).

5. The casting process for a robot shoulder joint shell according to claim 4, characterized in that, A connecting groove is provided on the side of the L-shaped hole away from the short axis, which passes through the outer side of the lower sand box (12). A movable fitting part (52) is inserted into the connecting groove. The outer side of the movable fitting part (52) is locked to the outer side of the lower sand box (12) by an outer plate (13).

6. The casting process for a robot shoulder joint shell according to claim 5, characterized in that, The movable mating part (52) includes a fixing part (521) that connects to the outer plate (13), and an adjusting spring (522) is connected to the other end of the fixing part (521). The adjusting spring (522) has a blocking part (523) that cooperates with the movable through plate (51).

7. The casting process for a robot shoulder joint shell according to claim 6, characterized in that, The sealing part (523) includes a movable baffle (5231) connected to the adjusting spring (522), and a plurality of blocking posts (5232) corresponding to the flow holes of the movable through plate (51) are fixed on the movable baffle (5231).

8. The casting process for a robot shoulder joint shell according to claim 1, characterized in that, The movable mating part (52) is located below the centerline of the molding cavity.

9. The casting process for a robot shoulder joint shell according to claim 1, characterized in that, The first pouring speed is 0.4 to 0.8 kg / s, the second pouring speed is 0.8 to 1.2 kg / s, and the third pouring speed is 0.2 to 0.5 kg / s.

10. The casting process for a robot shoulder joint shell according to claim 9, characterized in that, The vacuum level inside the molding cavity is -0.06 to -0.09 MPa.

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