Sand-forming additive manufacturing multilevel cyclic forming method and apparatus

Abstract

The application discloses a sand mold additive manufacturing multilevel circulation forming method and device, which mainly comprises a synchronous belt circulation mechanism, a sand mold printing self-lifting mechanism and a sand box forming mechanism. The synchronous belt circulation mechanism realizes the circulation printing of the sand mold printing self-lifting mechanism, the sand mold printing self-lifting mechanism realizes the multilevel compound of scraping sand and printing, and the sand mold forming mechanism provides sand feeding and the accumulation of the printing area sand, and simultaneously cooperates with the synchronous descending of the sand mold printing self-lifting mechanism to print the sand box bottom plate. Through the reorganization and circulation printing of the sand mold printing self-lifting mechanism in multiple sand boxes, the printing speed can be further accelerated, the casting production capacity can be improved, and energy can be saved, thereby laying a foundation for the rapid production of sand mold printing, accelerating the industrialization development speed of the sand mold printing, and enabling the high-quality development of the manufacturing industry.

Description

Technical Field

[0001] This invention belongs to the field of sand mold 3D printing, and relates to multi-layer and sand-lay printing methods and apparatus, particularly to multi-level cyclic forming methods and apparatus for sand mold additive manufacturing. Background Technology

[0002] In recent years, significant progress has been made in the development of high-performance, high-quality castings. Among them, sand casting continues to play an important role in today's industrial fields due to its low cost, high manufacturing flexibility, large design freedom, and wide applicability. Furthermore, with the introduction of advanced technologies such as computer-aided design and 3D printing, and with continuous technological development, sand casting's advantages in improving production efficiency and conserving resources have become even more prominent.

[0003] With the rise of sand mold 3D printing technology, single-piece, small-batch, and complex-shaped thin-walled parts are gradually being formed using sand mold 3D printing. Sand mold 3D printing manufactures the sand molds needed for casting by stacking layers of molding sand and printing layer by layer. However, this method has a long overall printing time, which does not meet the needs of rapid industrial development. Therefore, improving the overall forming time of sand molds has become a development trend. Currently, improving the overall forming time of sand molds mainly involves increasing the printing speed of the nozzles, higher-speed control systems, better software and processes, and using multi-nozzle collaborative printing to improve production efficiency. Beijing Jike Guochuang Lightweight Science Research Institute Co., Ltd. has applied for a patent, "A 3D Printing Forming Method," application number "CN202011046482.6." This patent improves the overall printing efficiency by completing two printing cycles and two sand laying cycles. However, this patent still has the problem of needing to return empty after printing and not being able to perform efficient cyclic printing. In the overall printing process, the printing time of a single layer can be completed through a better control system and multi-head collaborative printing. Multi-level cyclic printing requires the inkjet system to perform cyclic printing, as well as the design of a device that can move autonomously up and down and the algorithm for recombining casting slices. At present, further research is needed to improve the overall printing time of multiple layers through multi-level composite printing. Summary of the Invention

[0004] To address the aforementioned issues, this invention discloses a multi-level cyclic forming method and apparatus for sand mold additive manufacturing. This apparatus achieves efficient and rapid overall forming of the sand mold by cyclically printing multiple sand boxes in multiple levels, ensuring that each sand box continuously has multiple levels of sand laying and printing occurring simultaneously.

[0005] The device consists of a synchronous belt circulation mechanism, a sand mold printing self-lifting mechanism, and a sand box forming mechanism. The synchronous belt circulation mechanism comprises an outer track, an inner track, a support, a synchronous belt, gears, gear covers, a drive shaft, and a stepper motor. The support supports the outer and inner tracks. The inner side of the synchronous belt meshes with the gears, which are secured by gear covers. One end of the drive shaft is fixed to the gears, and the other end is fixed to the stepper motor. The distance between the inner and outer tracks is equidistant at all points. The sand mold printing self-lifting mechanism comprises a printing system, a slider table, a lifting device, a slider connecting seat, a scraper seat, a printing connecting beam, a motor mounting seat, a servo motor, a slider connecting seat, a scraper, a drag chain, a base, and a hinge structure. The slider table is bolted to the hinge structure, and the lifting device is fixedly mounted on the slider table. On the platform, the lifting device is bolted to the slide connecting seat, which is bolted to the scraper seat and the printing connecting beam. The scraper is fixedly installed on the scraper seat, and the printing connecting beam is fixedly installed on the base. A motor mounting seat is fixedly installed at one end of the base, and the servo motor is installed on the motor mounting seat. A slider connecting seat is installed on one side, and the printing system is installed on the slider connecting seat. At the same time, one end of the drag chain is connected to the printing system, and the whole structure is placed flat on the printing base. The sand box forming mechanism mainly consists of a printing sand box, lifting mechanism one, motor one, upper sand box, lifting mechanism two, and motor two. In lifting mechanism one, the sand box bottom plate moves up and down in the printing sand box under the control of motor one. In lifting mechanism two, the sand box bottom plate moves up and down in the upper sand box under the control of motor two.

[0006] Furthermore, the outer and inner tracks are elliptical in shape, parallel to each other, and the slider platform is fixed to the tracks by hinges for movement.

[0007] Furthermore, the length of the scraper should be 1-2 cm shorter than the printing sand box, and the distance from both sides of the scraper to the side plate of the printing sand box should be equal.

[0008] Furthermore, the lifting device uses a ball screw for precision lifting.

[0009] Furthermore, the synchronous belt is a composite synchronous belt, which contains metals, fibers and other materials to enhance the overall strength of the belt, and has rubber on the outside to increase the toughness and elasticity of the outer side of the synchronous belt.

[0010] Furthermore, the distance between each sand mold printing self-lifting mechanism is equal, and the distance is two widths;

[0011] The sand mold additive manufacturing multi-level cyclic forming method involves slicing the printed sand mold in each sand box, reassembling the slices, controlling motor two to drive the bottom plate of the sand box in lifting mechanism two to apply sand, activating stepper motors to drive synchronous belts to move, and synchronous belts to drive the sand mold printing self-lifting mechanism. When the sand mold printing self-lifting mechanism has traveled one width, the stepper motor stops, and the servo motor is activated to drive the printing system for inkjet printing. Every two widths the sand mold printing self-lifting mechanism travels, the next sand mold is printed.

[0012] The self-lifting mechanism just reaches the printing sand box. The sand mold printing self-lifting mechanism and the lifting mechanism are controlled to descend synchronously by one layer thickness. When the sand mold printing self-lifting mechanism reaches the last group of printing sand boxes, the sand box printing self-lifting mechanism rises to 2mm away from the printing surface after printing is completed. This cycle continues until the entire printing is completed.

[0013] Furthermore, the width of the pattern on the casting slice should be 3-4 cm less than the width of the printing sand box, and the length should be less than h of the printing sand box. The pattern should be centered on the slice, where h is the total length of the sand box minus the distance from the slide connecting seat to the printing system minus 2 mm.

[0014] The distance between each sand mold printing self-lifting mechanism is equal, and the distance is two widths. When the sand mold printing self-lifting mechanism reaches the last one to be printed, its rising speed after printing is completed is c times its falling speed, where c is the number of sand mold printing self-lifting mechanisms that are printing on a printing sand box at the same time.

[0015] Furthermore, each sand mold printing self-lifting mechanism does not print while on the semi-circular track, but only moves with the synchronous belt. It prints when it reaches the sand box. At the start of printing, only the sand mold self-lifting mechanism located at the printing start position of the first printing sand box scrapes sand and prints. Then, when the next sand mold self-lifting mechanism reaches the printing start position, it scrapes sand and prints. After each sand mold self-lifting mechanism has printed, the printing cycle begins.

[0016] After adopting the above technical solution, the beneficial effects of the present invention are:

[0017] 1. By designing a sand mold printing self-lifting device, multiple sand mold printing inkjet mechanisms can simultaneously perform printing work in the printing sand box, filling the current problem of idle stroke and coordinated printing in multiple printing systems working at the same time;

[0018] 2. The use of an "elliptical" track design ensures that the distance between each sand mold printing inkjet unit is equal, while simultaneously enabling the sand mold printing inkjet unit to print in a cyclic manner, further improving printing efficiency;

[0019] 3. By working in tandem with the sand printing inkjet mechanism, multi-level high-efficiency composite printing of sand molds can be achieved, which can greatly improve the overall efficiency of sand mold printing. Multiple sand molds can be quickly formed and solidified in a short time, increasing production capacity and saving energy. This lays the foundation for the rapid production of sand mold printing and accelerates the industrialization of sand mold printing. Attached Figure Description

[0020] Figure 1 General drawing of a multi-stage cyclic forming method and apparatus for sand mold additive manufacturing;

[0021] Figure 2 Top view of a multi-stage cyclic forming method and apparatus for sand mold additive manufacturing;

[0022] Figure 3 Cross-sectional view of the sand box portion of the method and apparatus for multi-level cyclic forming of sand mold additive manufacturing;

[0023] Figure 4 Enlarged view of part A in the multi-stage cyclic forming method and apparatus for sand mold additive manufacturing;

[0024] Figure 5 Enlarged view of part B in the multi-level cyclic forming method and apparatus for sand mold additive manufacturing;

[0025] Figure 6 Enlarged view of part C in the multi-level cyclic forming method and apparatus for sand mold additive manufacturing;

[0026] Figure 7 A schematic diagram of a multi-level composite process and apparatus for multi-level cyclic forming in sand-mold additive manufacturing.

[0027] Figure 8 A schematic diagram of the motion of a multi-level cyclic forming method and apparatus for sand mold additive manufacturing;

[0028] Figure 9 Enlarged view of the self-lifting printing mechanism in the multi-level cyclic forming method and apparatus for sand mold additive manufacturing;

[0029] The attached diagram illustrates: 1. Outer track; 2. Inner track; 3. Support; 4. Synchronous belt; 5. Gear; 6. Gear cover; 7. Drive shaft; 8. Stepper motor; 9. Printing system; 10. Slider table; 11. Lifting device; 12. Slider table connecting seat; 13. Scraper seat; 14. Printing connecting beam; 15. Motor mounting seat; 16. Servo motor; 17. Slider connecting seat; 18. Base; 19. Hinge structure; 20. Scraper; 21. Printing sand box; 22. Lifting mechanism 1; 23. Motor 1; 24. Sand loading box; 25. Lifting mechanism 2; 26. Motor 2; 27. Cable chain. Detailed Implementation

[0030] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. It should be noted that the terms "front," "rear," "left," "right," "up," and "down" used in the following description refer to directions in the accompanying drawings, and the terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0031] like Figure 1-6 As shown, the sand mold additive manufacturing multi-level cyclic forming device of this embodiment consists of a synchronous belt circulation mechanism, a sand mold printing self-lifting mechanism, and a sand box forming mechanism. The synchronous belt circulation mechanism consists of an outer track 1, an inner track 2, a bracket 3, a synchronous belt 4, a gear 5, a gear cover 6, a drive shaft 7, and a stepper motor 8. The bracket 3 is used to support the outer track 1 and the inner track 2. The inner side of the synchronous belt 4 meshes with the gear. The gear 5 is equipped with a gear cover 6 for fixing the gear 5. One end of the drive shaft 7 is fixedly connected to the gear 5, and the other end is fixed to the stepper motor 8. The distance between the inner track 2 and the outer track 1 is equal everywhere.

[0032] like Figure 9 As shown, the sand mold printing self-lifting mechanism consists of a printing system 9, a slider table 10, a lifting device 11, a slider connecting seat 12, a scraper seat 13, a printing connecting beam 14, a motor mounting seat 15, a servo motor 16, a slider connecting seat 17, a scraper 20, a drag chain 27, a base 18, and a hinge structure 19. The slider table 10 is fixed to the hinge structure 19 by bolts. The lifting device 11 is fixedly installed on the slider table 10. The lifting device 11 is bolted to the slider connecting seat 12. The slider connecting seat 12 is bolted to the scraper seat 13 and the printing connecting beam 14. The scraper 20 is fixedly installed on the scraper seat 13. The printing connecting beam 14 is fixedly installed on the base 18. The motor mounting seat 15 is fixedly installed at one end of the base. The servo motor 16 is installed on the motor mounting seat 15. The slider connecting seat 17 is installed on one side. The printing system 9 is installed on the slider connecting seat 17. At the same time, one end of the drag chain 27 is connected to the printing system 9. The whole structure is placed flat on the printing base 18.

[0033] The sand box forming mechanism mainly consists of a printing sand box 21, a lifting mechanism 1 22, a motor 1 23, an upper sand box 24, a lifting mechanism 2 25, and a motor 2 26. In the lifting mechanism 1 22, the bottom plate of the sand box moves up and down within the printing sand box 21 under the control of motor 1 23. In the lifting mechanism 2 25, the bottom plate of the sand box moves up and down within the upper sand box 24 under the control of motor 226.

[0034] The outer track 1 and inner track 2 are elliptical in shape and parallel to each other. The slider table 10 is fixed to the track by a hinge mechanism 19 for movement. The scraper 20 is 2cm shorter than the printing sand box 21, and the distances from both sides of the scraper 20 to the side plates of the printing sand box 21 are equal. The lifting device 11 uses a ball screw for precision lifting. The synchronous belt 4 is a composite synchronous belt containing metal and fiber to enhance the overall strength of the belt, and rubber on the outside to increase the toughness and elasticity of the outer side of the synchronous belt. The distance between each sand mold printing self-lifting mechanism is equal, and the distance is two widths.

[0035] The sand mold additive manufacturing multi-level cyclic forming method involves slicing the printed sand mold in each sand box, reassembling the slices, controlling motor 26 to drive the lifting mechanism 25 to load sand onto the bottom plate of the sand box, activating stepper motor 8 to drive synchronous belt 4, and synchronous belt 4 to drive the sand mold printing self-lifting mechanism. When the sand mold printing self-lifting mechanism has traveled one width, stepper motor 8 stops, and servo motor 16 is activated to drive printing system 9 for inkjet printing. Every two widths, the sand mold printing self-lifting mechanism reaches the printing sand box 21. By controlling the sand mold printing self-lifting mechanism and lifting mechanism 22 to descend synchronously by one layer thickness, the sand mold printing self-lifting mechanism reaches the printing sand box 21; when it is the last one, after printing, the sand box printing self-lifting mechanism rises to a position 2mm away from the printing surface. This cycle continues until the entire printing is completed.

[0036] The distance between each sand mold printing self-lifting mechanism is equal, and the distance is two widths. When the sand mold printing self-lifting mechanism reaches the last one to be printed, its rising speed after printing is completed is c times its falling speed, where c is the number of sand mold printing self-lifting mechanisms that are printing on a printing sand box at the same time.

[0037] Each sand mold printing self-lifting mechanism does not print while on the semi-circular track, but only moves with the synchronous belt. Printing begins when it reaches the printing sand box 21. At the start of printing, only the sand mold self-lifting mechanism at the printing start position scrapes sand and prints. Then, the next sand mold self-lifting mechanism scrapes sand and prints when it reaches the printing start position. Printing continues cyclically after each sand mold self-lifting mechanism has finished printing. Figure 8 As shown, the sand mold self-lifting mechanism 1 starts printing in sand box 1, while the other sand mold self-lifting mechanisms do not print. When the sand mold self-lifting mechanism 1 completes two widths, the sand mold self-lifting mechanism 1 and the printing sand box bottom plate descend synchronously by one layer thickness, and the sand mold self-lifting mechanisms 2 and 1 start printing. When the sand mold self-lifting mechanism 22 starts printing in sand box 1, all printing systems start cyclic operation, which improves the efficiency of bidirectional sand laying printing by more than 3 times.

[0038] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features.

Claims

1. A sand pattern additive manufacturing multilevel cyclic forming method, characterized by, A multi-level cyclic forming device for sand mold additive manufacturing is used for processing. The device consists of a synchronous belt circulation mechanism, a sand mold printing self-lifting mechanism, and a sand box forming mechanism. The synchronous belt circulation mechanism consists of an outer track (1), an inner track (2), a bracket (3), a synchronous belt (4), a gear (5), a drive shaft (7), and a stepper motor (8). The bracket (3) is used to support the outer track (1) and the inner track (2). The inner side of the synchronous belt (4) meshes with the gear (5). One end of the drive shaft (7) is fixedly connected to the gear (5), and the other end is connected to the stepper motor (8). 8) Connection, the distance between the inner track (2) and the outer track (1) is equal everywhere; the sand box forming mechanism is mainly composed of printing sand box (21), lifting mechanism one (22), motor one (23), upper sand box (24), lifting mechanism two (25), and motor two (26). The bottom plate of the sand box in lifting mechanism one (22) moves up and down in the printing sand box (21) under the control of motor one (23), and the bottom plate of the sand box in lifting mechanism two (25) moves up and down in the upper sand box (24) under the control of motor two (26); And includes the following steps: Step 1: Slice the printed sand pattern in each sand box, reassemble the slice set, control motor 2 (26) to drive the bottom plate of the sand box in the lifting mechanism 2 (25) to load sand, turn on stepper motor (8) to drive synchronous belt (4) to move, and synchronous belt (4) to drive the sand pattern printing self-lifting mechanism to move. Step 2: When the sand mold printing self-lifting mechanism runs for one width, the stepper motor (8) stops moving and the servo motor (16) is started to drive the printing system (9) to perform inkjet printing. When the sand mold printing self-lifting mechanism runs for two widths, the next sand mold printing self-lifting mechanism just arrives at the printing sand box (21). Control the sand mold printing self-lifting mechanism and the lifting mechanism one (22) to descend synchronously by one layer thickness. Step 3: When the sand mold printing self-lifting mechanism reaches the last sand box (21), after printing is finished, the sand box printing self-lifting mechanism rises to a distance of 2mm from the printing surface, and this cycle continues until the overall printing is finished.

2. The sand pattern additive manufacturing multilevel cyclic forming method of claim 1, wherein, in, The width of the pattern on the casting slice is 4cm less than the width of the printing sand box (21), and the length is less than the total length h of the printing sand box. The pattern is centered on the slice. h is the total length of the sand box minus the distance from the slide connecting seat to the printing system minus 2mm.

3. The sand form additive manufacturing multilevel cyclic forming method of claim 1 wherein, The distance between each sand mold printing self-lifting mechanism is equal, and the distance is two widths. When the sand mold printing self-lifting mechanism reaches the last one to be printed, its rising speed after printing is completed is c times its falling speed, where c is the number of sand mold printing self-lifting mechanisms that are printing on a printing sand box at the same time.

4. The sand form additive manufacturing multilevel cyclic forming method of claim 3, wherein, Each sand mold printing self-lifting mechanism does not print while on the semi-circular track, but only moves with the synchronous belt. It prints when it reaches the sand box. At the start of printing, only the sand mold self-lifting mechanism located at the printing start position scrapes sand and prints. Then, when the next sand mold self-lifting mechanism reaches the printing start position, it scrapes sand and prints. After each sand mold self-lifting mechanism has printed, the printing cycle begins.

5. The sand pattern additive manufacturing multilevel cyclic forming method of claim 1, wherein, The sand mold printing self-lifting mechanism consists of a printing system (9), a slider table (10), a lifting device (11), a slider connecting seat (12), a scraper seat (13), a printing connecting beam (14), a motor mounting seat (15), a servo motor (16), a slider connecting seat (17), a scraper (20), a drag chain (27), a base (18), and a hinge structure (19). The slider table (10) is fixed on the hinge structure (19). The bottom of the lifting device (11) is fixedly installed on the slider table (10), and the top is fixedly connected to the slider connecting seat (12). The slider connecting seat (12) The side is fixed with a scraper seat (13) and a printing connecting beam (14). The scraper (20) is fixedly installed on the scraper seat (13). The printing connecting beam (14) is fixedly installed on the base (18). A motor mounting seat (15) is fixedly installed at one end of the base (18). The servo motor (16) is installed on the motor mounting seat (15). A slider connecting seat (17) is installed on one side of the motor mounting seat (15). The printing system (9) is installed on the slider connecting seat (17). At the same time, one end of the drag chain (27) is connected to the printing system (9). The whole is placed flat on the printing base (18).

6. The sand pattern additive manufacturing multilevel cyclic forming method of claim 1, wherein, in, The outer track (1) and the inner track (2) are parallel. The length of the scraper (20) is 2cm less than that of the printing sand box (21), and the distance from both sides of the scraper (20) to the side plate of the printing sand box (21) is equal. The gear (5) is equipped with a gear cover (6) for fixing the gear (5).

7. The sand mold additive manufacturing multi-stage cyclic forming method according to claim 5, characterized in that, The lifting device (11) uses a ball screw for precision lifting; the synchronous belt (4) uses a composite synchronous belt with rubber on the outside to increase the toughness and elasticity of the outer side of the synchronous belt; the distance between each sand mold printing self-lifting mechanism is equal, and the distance is two widths.

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