Large-size sand mold 3D printing equipment capable of alternately running sand paving and printing

Abstract

The invention relates to the technical field of additive manufacturing, and discloses large-size sand mold 3D printing equipment capable of alternately running sanding and printing, which comprises an equipment main frame, a forming cylinder, a sanding driving system, a sand supply system, a sanding vehicle, a printing driving system and a printing vehicle, the forming cylinder can automatically enter and exit from the interior of the equipment main frame, a forming cylinder printing area square hole is formed in the upper portion of the equipment main frame, and a piston plate capable of moving up and down is arranged in the forming cylinder; the sanding vehicle is controlled by a sanding driving system to run along the narrow edge direction of the square hole in the printing area of the forming cylinder; the printing vehicle is controlled by a printing driving system to run along the wide edge direction of the square hole in the printing area of the forming cylinder; the moving direction of the sanding vehicle is perpendicular to the moving direction of the printing vehicle, and during working, the sanding vehicle and the printing vehicle run in a staggered mode, so that staggered actions of sanding and printing are achieved. The 3D printer is simple and reasonable in structure, and has the characteristics of high efficiency and high stability when being used for 3D printing of large-size sand mold parts.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and more specifically, to a large-size sand mold 3D printing device with interleaved operation of sand spreading and printing. Background Art

[0002] The sand mold 3D printing technology is a rapid manufacturing technology extended and applied to the production of casting sand molds based on the original 3D printing technology. That is, sand mold 3D printing is an innovative technology for traditional sand mold casting processes. Its basic principle is to use a 3D printing device to stack resin sand containing a curing agent layer by layer according to a digital three-dimensional model to form a sand mold cavity for pouring, replacing the original method of making a sand mold cavity with a mold, reducing the manufacturing cost and shortening the processing cycle. Especially for large-size castings, the 3D printing process saves a large amount of time and processing cost compared with the traditional process. Currently, the market demand for sand mold 3D printing devices is increasing continuously.

[0003] The working principles of current sand mold 3D printing devices are basically the same. The printing process adopts an automatic sand supply method. Sand spreading and printing are respectively driven by separate belt modules. The two driving modules are arranged in the same direction. The sand spreading vehicle and the printing vehicle are respectively located at both ends of the driving module. During printing, the powder spreading vehicle and the printing vehicle sequentially complete repetitive movements of sand spreading, returning, printing, and returning along the driving belt module. This structure of sand mold 3D printing device has the advantages of high printing efficiency, flexible production process, and low equipment manufacturing cost when producing small-size sand mold parts. However, with the increasing size of printed sand mold parts and the increasing number of printed parts, the disadvantages of this sand mold 3D printing device with sand spreading and printing running in the same direction are exposed. First, the sand spreading and printing beat is slow and the printing time is long, greatly reducing the production efficiency. Second, for this large-size 3D printing device, to improve the printing efficiency, a large number of nozzles need to be used on the printing vehicle, and the cost of the nozzles is high, resulting in a high overall equipment manufacturing cost. Third, in a large-size sand mold 3D printing device, during the long-distance movement of the belt module, the disadvantages of low precision, slow speed, and unstable structure are likely to cause the scrapping of printed parts, affecting the printing stability of the 3D printing device, causing printing interruptions, and affecting the printing quality.

[0004] For example, in a Chinese invention patent CN 113290856 A, an inkjet 3D printer adopts a structure where the powder spreading trolley and the inkjet printing trolley independently reciprocate along the X-axis direction. Among them, the powder spreading trolley is installed on the side close to the feeding system, and the inkjet printing trolley is installed on the side close to the nozzle cleaning device. During printing, the two trolleys independently reciprocate along the X-axis direction. This structure has a slow sand spreading and printing beat, a long printing time, and extremely low production efficiency.

[0005] Therefore, when designing and manufacturing a large-size sand mold 3D printer, how to provide a complete machine device with a simple motion structure, stable performance, high printing efficiency, low cost, and also meet the usage requirements of printing large-size parts and batch parts is a problem that needs to be solved currently. Summary of the Invention

[0006] In view of this, the present invention provides a large-size sand mold 3D printing device with staggered operation of sand spreading and printing, and its specific technical solution is as follows:

[0007] A large-size sand mold 3D printing device with staggered operation of sand spreading and printing includes a main device frame, a forming cylinder, a sand spreading driving system, a sand supply system, a sand spreading vehicle, a printing driving system, and a printing vehicle; wherein, the forming cylinder can automatically enter and exit the interior of the main device frame, a square hole for the forming cylinder printing area is opened in the upper part of the main device frame, the printing position of the forming cylinder is located below the square hole of the forming cylinder printing area, a piston plate capable of moving up and down is arranged inside the forming cylinder, and the piston area of the forming cylinder corresponds to the upper square hole of the forming cylinder printing area; sand spreading driving systems are arranged along both sides of the narrow edge of the square hole of the forming cylinder printing area in the upper part of the main device frame, and the sand spreading vehicle is controlled by the sand spreading driving system to run along the narrow edge direction of the square hole of the forming cylinder printing area; the sand supply system is arranged at one end of the sand spreading driving system, and its length direction is parallel to the sand spreading vehicle, and the discharge port of the sand supply system is located above the sand spreading vehicle to continuously provide sand material for the sand spreading vehicle; a printing driving system is also arranged on the top of the main device frame, and the printing vehicle is controlled by the printing driving system to run along the wide edge direction of the square hole of the forming cylinder printing area; the moving direction of the sand spreading vehicle is perpendicular to the moving direction of the printing vehicle, and during operation, the sand spreading vehicle and the printing vehicle operate in a staggered manner to achieve the staggered actions of sand spreading and printing.

[0008] Preferably, the exterior of the forming cylinder is a rectangular cylinder consisting of four side cylinder plates and a cylinder bottom plate. Taking the movement direction of the forming cylinder as the front-to-back direction, vertical side cylinder plate long strip holes are symmetrically opened on the left cylinder plate and the right cylinder plate of the forming cylinder. The piston plate is adapted to the inner cavity shape of the rectangular cylinder, and piston plate sealing strips that are in close contact with the inner wall of the rectangular cylinder are evenly arranged around the piston plate; a piston plate support block is respectively connected to the bottom surface of the two symmetrical sides of the piston plate, and the connection position of the piston plate support block corresponds to the long strip hole of the side cylinder plate. The piston plate support block can extend from the long strip hole of the side cylinder plate to the outside of the rectangular cylinder, and move up and down with the piston plate within the range of the long strip hole of the side cylinder plate; there is a mounting hole between the piston plate support block and the piston plate above it. Space, in the installation space, a belt pressing wheel and a guide wheel rotatably connected to the bottom surface of the piston plate are arranged side by side on the left and right, and the belt pressing wheel is closer to the long strip hole of the side cylinder plate; a sealing steel belt is respectively arranged on the left and right inner walls of the rectangular cylinder along the long strip hole of the side cylinder plate, and the width of the sealing steel belt is greater than the width of the long strip hole of the side cylinder plate, and can completely cover the long strip hole of the side cylinder plate; the upper end of each sealing steel belt is fixed to the upper end surface of the corresponding side cylinder plate through a sealing steel belt fixing block, the sealing steel belt passes downward through the gap between the piston plate sealing strip and the corresponding rectangular cylinder inner wall, and passes through the corresponding belt pressing wheel and guide wheel in sequence in an S shape, and at the same time the belt pressing wheel presses the sealing steel belt tightly against the corresponding side cylinder plate, and the lower end of the sealing steel belt is connected to the corresponding sealing steel belt tensioning mechanism below.

[0009] Preferably, the sealing steel belt tensioning mechanism is fixed to the cylinder bottom plate and is on a vertical line with the corresponding side cylinder plate elongated hole and the piston plate support block; the sealing steel belt tensioning mechanism includes a fixing frame installed on the cylinder bottom plate, and a slider seat is installed on the outer wall of the fixing frame facing the side cylinder plate elongated hole, and two vertical guide shafts are fixed side by side on both sides of the slider seat, and an adjustment slider, a spring, and a tensioning slider are installed on the guide shaft from top to bottom in sequence; the adjusting bolt passes through the slider seat and the adjusting slider downward from the middle of the upper end face of the slider seat, and is threadedly connected to the adjusting slider; a steel belt fixing plate for fixing the lower end of the sealing steel belt is installed on the outer wall of the tensioning slider facing the side cylinder plate elongated hole.

[0010] Preferably, the main frame of the equipment includes a main frame structure, two track wheel groups are installed in parallel on both sides of the inner bottom plate of the main frame structure, all the track wheels in each track wheel group are connected in series by a track wheel transmission chain, and a track wheel drive motor is installed under the inner bottom plate of the main frame structure between the two track wheel groups. The track wheel drive motor is connected to the drive shafts on both sides and controls the drive shafts to drive the track wheels on both sides to rotate synchronously; the forming cylinder is placed on the two track wheel groups and can enter and exit the main frame of the equipment along the movement direction of the track wheels under the rolling friction of the track wheels.

[0011] Preferably, it further includes a Z-axis lifting system for driving the piston plate in the forming cylinder to move in the Z-axis direction. The Z-axis lifting system is located inside the main frame structure. Bearing seat holes for installing the Z-axis lifting system are provided on the upper table surfaces and the lower table surfaces on the left and right sides of the main frame structure. Upper bearing seats are respectively installed in the two upper bearing seat holes located above, and lower bearing seats are respectively installed in the two lower bearing seat holes located below. The Z-axis lifting system includes a first transmission lead screw and a second transmission lead screw respectively arranged on the left and right sides and connected to the upper and lower bearing seats on the corresponding sides. Linear guide rails are also fixed on the inner guide rail surfaces on the left and right sides of the main frame structure. A lifting slide is installed between the two guide rail sliders on the same-side linear guide rail. The lifting slide is connected to the transmission lead screw on the corresponding side and moves through the driving force of the corresponding transmission lead screw. A support seat corresponding to the position of the piston plate support block is installed on the side wall of the lifting slide facing the forming cylinder. The lower ends of the first transmission lead screw and the second transmission lead screw are respectively connected to a first commutator. The two first commutators are respectively connected to a second commutator located in the middle through a first transmission shaft. The Z-axis lifting drive motor is connected to the second commutator.

[0012] Preferably, a sand spreading drive system installation plane is provided on the upper table surface of the main frame structure. The sand spreading drive system includes a first drive module and a second drive module respectively located on both sides of the narrow side of the square hole in the printing area of the forming cylinder. A second transmission shaft is arranged between the two drive modules. The second transmission shaft is driven to rotate by a sand spreading drive motor through a pulley and a transmission belt. Each of the two drive modules is provided with a conveyor belt controlled to rotate by the second transmission shaft. Module sliders are installed on the conveyor belt. The two drive modules are connected through the second transmission shaft to realize the synchronous operation of the two module sliders. The sand spreading vehicle is connected to the module slider in the sand spreading drive system. Driven by the sand spreading drive motor, the sand spreading vehicle can reciprocally run along the narrow side direction of the square hole in the printing area of the forming cylinder.

[0013] Preferably, the sand supply system is fixed on the upper table surface of the main frame structure through a support beam. The sand supply system includes a gas-sand separator, a spiral leveling bin, and a indexing blanking bin. The feeding pipe of the gas-sand separator is connected to the spiral leveling bin inlet in the middle of the top end of the spiral leveling bin. First spiral blades and second spiral blades with equal lengths are arranged along the axial direction in the spiral leveling bin. The first spiral blades and the second spiral blades are installed on the same spiral leveling shaft and have opposite spiral directions. The demarcation point between the first spiral blades and the second spiral blades is located at the spiral leveling bin inlet. One end of the spiral leveling shaft is connected to the spiral blade drive motor. There is a connecting guide bin between the spiral leveling bin and the indexing blanking bin to connect the spiral leveling bin and the indexing blanking bin with each other.

[0014] Preferably, an indexing blanking shaft is installed in the indexing blanking bin. A number of blades are evenly distributed radially on the outer circle of the indexing blanking shaft. One end of the indexing blanking shaft is connected to the indexing blanking motor. An outlet is provided at the lower end of the indexing blanking bin.

[0015] Preferably, the gas-sand separator includes a conical cabin body with its upper part connected to the feeding pipe. An annular air guide plate is provided at and above the feeding port of the conical cabin body. Meanwhile, a gas outlet is provided at the top of the conical cabin body, and a deceleration plate is provided at the gas outlet. A number of small holes are opened on the deceleration plate, and a filter element is also installed at the gas outlet above the deceleration plate. The outside of the filter element is integrally covered by a protective cover, and a number of air outlet holes are opened on the outer peripheral wall of the protective cover; a level switch is provided below the feeding port of the conical cabin body, and the level switch is located in the upper middle part of the conical cabin body; a discharging pipe is provided at the bottom of the conical cabin body, and a gate is installed at the discharging pipe.

[0016] Preferably, a printing drive support is further installed above the upper surface of the main frame structure. The printing drive system includes two groups of printing drive modules horizontally arranged corresponding to the printing drive support and printing drive sliders slidably installed corresponding to the bottom of the printing drive modules. The printing drive module is a linear motor drive module. The two printing drive sliders achieve motion synchronization through gantry control, and the motion direction of the printing drive sliders is consistent with the wide side direction of the square hole in the printing area of the forming cylinder; the printing vehicle is connected to the two printing drive sliders, so that the moving direction of the sand spreading vehicle is perpendicular to the moving direction of the printing vehicle.

[0017] Compared with the prior art, the present invention provides a large-size sand mold 3D printing device with staggered operation of sand spreading and printing, and specifically provides a structure with vertical staggered operation of sand spreading and printing. This structure is simple and reasonable, and when 3D printing large-size sand mold parts, since the running path length of the sand spreading machine is effectively shortened, it has the characteristics of high efficiency and high stability.

[0018] In order to improve the printing efficiency of the sand mold 3D printer for large-size parts, ensure the printing stability during the printing process, and reduce the technical function deficiencies such as the printing cost of large-size parts, and in combination with the related technologies of the existing sand mold 3D printing equipment, through the improvement of the moving directions of powder spreading and printing, and the improvement of the structures of the powder supply system, drive system, and forming cylinder, the powder spreading and printing rhythm of the large-size sand mold 3D printing device is made more compact, the performance of the sand material supply system is stable and reliable. Through the improvement of the forming cylinder structure, the lifting method of the Z-axis during the printing process is changed, and the structure of entering and exiting the cylinder is optimized, so that the general performance of the whole machine equipment is extensive, it is easier to be connected in line with multiple devices, and large-scale production is expanded. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings described below are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0020] Figure 1 Schematic diagram of the internal structure of a large - size sand mold 3D printing device with alternating sand spreading and printing according to the present invention.

[0021] Figure 2 Schematic diagram of the structure of the main frame of the device.

[0022] Figure 3 Overall structure schematic diagram of the forming cylinder.

[0023] Figure 4 Longitudinal sectional view of the forming cylinder.

[0024] Figure 5 For Figure 4 Enlarged structure diagram of the part indicated by Ⅰ in

[0025] Figure 6 Schematic diagram of the structure of the sealing steel belt tensioning mechanism.

[0026] Figure 7 Schematic diagram of the structure of the Z - axis lifting system.

[0027] Figure 8 Schematic diagram of the structure of the sand spreading drive system.

[0028] Figure 9 Schematic diagram of the structure of the sand supply system.

[0029] Figure 10 Partial longitudinal sectional view of the sand supply system.

[0030] Figure 11 Internal structure schematic diagram of the air - sand separator.

[0031] Figure 12 Working flow chart of an embodiment of the present invention.

[0032] Figure 13 Working flow chart of another embodiment of the present invention.

[0033] In the figure: 10 - main frame of the device, 11 - main frame structure, 111 - bearing seat hole, 112 - installation plane for the sand spreading drive system, 12 - track wheel, 13 - track wheel drive chain, 14 - track wheel drive motor, 15 - printing drive support, 20 - forming cylinder, 21 - side cylinder plate, 211 - long strip hole on the side cylinder plate, 22 - cylinder bottom plate, 23 - piston plate, 231 - piston plate sealing strip, 24 - piston plate support block, 25 - pressure belt wheel, 26 - guide wheel, 27 - sealing steel belt, 28 - sealing steel belt fixing block, 29 - sealing steel belt tensioning mechanism, 291 - fixing frame, 292 - slider seat, 293 - guide shaft, 294 - adjusting slider, 295 - spring, 296 - tensioning slider, 297 - adjusting bolt, 298 - steel belt fixing plate, 30 - Z-axis lifting system, 31A - upper bearing seat, 31B - lower bearing seat, 32 - first transmission lead screw, 33 - second transmission lead screw, 34 - linear guide rail, 35 - lifting slide table, 36 - support seat, 37 - first commutator, 38 - second commutator, 39 - Z-axis lifting drive motor, 40 - sand spreading drive system, 41 - first drive module, 42 - second drive module, 43 - second transmission shaft, 44 - sand spreading drive motor, 45 - belt pulley, 46 - transmission belt, 47 - module slider, 50 - sand supply system, 51 - air-sand separator, 511 - conical cabin, 512 - annular air guide plate, 513 - speed reduction plate, 514 - filter element, 515 - protective cover, 516 - level switch, 517 - blanking pipe, 518 - gate, 519 - feeding pipe, 52 - spiral sand spreading bin, 521 - first spiral blade, 522 - first spiral blade, 523 - spiral blade drive motor, 53 - indexing blanking bin, 531 - indexing blanking shaft, 532 - blade, 533 - indexing blanking motor, 534 - discharge port, 54 - support beam, 55 - material guiding bin, 60 - sand spreading vehicle, 70 - printing vehicle, 80 - printing drive system, 81 - printing drive module, 82 - printing drive slider. Detailed implementation manners

[0034] The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0035] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0036] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0037] Embodiment 1:

[0038] Referring to Figure 1 , this embodiment provides a large-size sand mold 3D printing device with alternating sand spreading and printing, mainly including a device main frame 10, a forming cylinder 20, a sand spreading drive system 40, a sand supply system 50, a sand spreading vehicle 60, a printing drive system 80, and a printing vehicle 70.

[0039] Among them, the forming cylinder 20 can automatically move in and out of the interior of the device main frame 10. A forming cylinder printing area square hole is provided in the upper part of the device main frame 10. The printing position of the forming cylinder 20 is located below the forming cylinder printing area square hole. A piston plate 23 capable of moving up and down is provided inside the forming cylinder 20, and the piston area of the forming cylinder 20 corresponds to the upper forming cylinder printing area square hole. The sand spreading drive system 40 is arranged along both sides of the narrow edge of the forming cylinder printing area square hole in the upper part of the device main frame 10. The sand spreading vehicle 60 is controlled by the sand spreading drive system 40 to move along the narrow edge direction of the forming cylinder printing area square hole. The sand supply system 50 is arranged at one end of the sand spreading drive system 40, and its length direction is parallel to the sand spreading vehicle 60. The discharge port 534 of the sand supply system 50 is located above the sand spreading vehicle 60 to continuously supply sand material to the sand spreading vehicle 60. A printing drive system 80 is also provided on the top of the device main frame 10. The printing vehicle 70 is controlled by the printing drive system 80 to move along the wide edge direction of the forming cylinder printing area square hole. The moving direction of the sand spreading vehicle 60 is perpendicular to the moving direction of the printing vehicle 70. During operation, the sand spreading vehicle 60 and the printing vehicle 70 move alternately to achieve the alternating actions of sand spreading and printing.

[0040] In a further specific embodiment, the device main frame 10 is a steel structure welded or assembled structure.

[0041] More specifically, referring to Figure 2The main frame 10 of the equipment includes a main frame structure 11, and the main frame structure 11 is mainly formed by welding steel pipes, and can also be formed by connecting steel pipes with bolts.

[0042] Two track wheel groups are installed in parallel on both sides of the inner bottom plate of the main frame structure 11. All the track wheels 12 in each track wheel group are connected in series by a track wheel transmission chain 13. A track wheel drive motor 14 is installed under the inner bottom plate of the main frame structure between the two track wheel groups. The track wheel drive motor 14 is connected to the drive shafts on both sides and controls the drive shafts to drive the track wheels 12 on both sides to rotate synchronously.

[0043] The forming cylinder 20 is placed on two track wheel sets, and can enter and exit the main frame 10 of the equipment along the moving direction of the track wheels under the rolling friction of the track wheels 12.

[0044] In further specific embodiments, see Figures 3 - 5 The outside of the forming cylinder 20 is a rectangular cylinder composed of four side cylinder plates 21 and a cylinder bottom plate 22. Specifically, the four side cylinder plates 21 are connected end to end by bolts or welded to form a square or rectangular cylinder wall structure, and the cylinder bottom plate 22 is connected to the cylinder wall composed of the side cylinder plates 21 to form a solid external cylinder body of the forming cylinder.

[0045] Taking the movement direction of the forming cylinder 20 as the front-to-back direction, vertical side cylinder plate elongated holes 211 are symmetrically opened on the left cylinder plate 21 and the right cylinder plate 21 of the forming cylinder 20, and the piston plate 23 is adapted to the inner cavity shape of the rectangular cylinder, that is, the piston plate 23 is a square or rectangular structure, and the piston plate 23 can move up and down in the rectangular cylinder, and piston plate sealing strips 231 that are in close contact with the inner wall of the rectangular cylinder are evenly arranged around the piston plate 23 to prevent the sand from falling through the gap between the piston plate 23 and the inner wall of the rectangular cylinder; a piston plate support block 24 is respectively connected to the bottom surface of the two symmetrical sides of the piston plate 23, and the connection position of the piston plate support block 24 corresponds to the side cylinder plate elongated hole 211, and the piston plate support block 24 can extend from the side cylinder plate elongated hole 211 to the outside of the rectangular cylinder, and move up and down with the piston plate 23 within the range of the side cylinder plate elongated hole.

[0046] There is an installation space left between the piston plate support block 24 and the piston plate 23 above it. In the installation space, a pressure belt wheel 25 and a guide wheel 26 that are rotationally connected to the bottom surface of the piston plate are arranged side by side from left to right. Moreover, the pressure belt wheel 25 is closer to the long strip hole 211 of the side cylinder plate. The pressure belt wheel 25 and the guide wheel 26 move up and down together with the piston plate 23. On the left and right inner walls of the rectangular cylinder, a sealing steel belt 27 is arranged along the long strip hole 211 of the side cylinder plate respectively. The width of the sealing steel belt 27 is greater than the width of the long strip hole 211 of the side cylinder plate and can completely cover the long strip hole 211 of the side cylinder plate. The upper end of each sealing steel belt 27 is fixed to the upper end surface of the corresponding side cylinder plate 21 through a sealing steel belt fixing block 28. The sealing steel belt 27 passes downward through the gap between the piston plate sealing strip 231 and the inner wall of the corresponding rectangular cylinder, and sequentially passes through the corresponding pressure belt wheel 25 and guide wheel 26 in an S shape. At the same time, the pressure belt wheel 25 tightly presses the sealing steel belt 27 against the corresponding side cylinder plate 21. The lower end of the sealing steel belt 27 is connected to the corresponding sealing steel belt tensioning mechanism 29 below.

[0047] Furthermore, referring to Figure 6 , the sealing steel belt tensioning mechanism 29 is fixed to the cylinder bottom plate 22 and is on the same vertical line as the long strip hole 211 of the side cylinder plate and the piston plate support block 24 on the corresponding side. The sealing steel belt tensioning mechanism 29 includes a fixing frame 291 installed on the cylinder bottom plate 22. A slider seat 292 is installed on the outer wall of the fixing frame 291 facing the long strip hole of the side cylinder plate. Two vertical guide shafts 293 are fixedly arranged on both sides of the slider seat 292. An adjusting slider 294, a spring 295, and a tensioning slider 296 are sequentially installed on the guide shafts 293 from top to bottom. An adjusting bolt 297 passes downward through the slider seat 292 from the middle of the upper end surface of the slider seat 292 and is threadedly connected to the adjusting slider 294. The adjusting bolt 297 tightens the adjusting slider 294 by adjusting the up and down position of the adjusting slider 294. A steel belt fixing plate 298 for fixing the lower end of the sealing steel belt is installed on the outer wall of the tensioning slider 296 facing the long strip hole of the side cylinder plate. That is, the steel belt fixing plate 298 fixes the sealing steel belt 27 to the tensioning slider 296. In this way, by rotating the adjusting bolt 297, the position of the adjusting slider 294 together with the tensioning slider 296 can be adjusted to tighten the sealing cylinder belt.

[0048] The spring 295 is located between the adjusting slider 294 and the tensioning slider 296 and provides a constant tension for the sealing steel belt 27 during movement.

[0049] In a further specific embodiment, a large-sized sand mold 3D printing device with alternating sand laying and printing further includes a Z-axis lifting system 30 that provides driving force for the piston plate 23 in the forming cylinder in the Z-axis direction. The Z-axis lifting system 30 is located inside the main frame structure 11. Bearing seat holes 111 for installing the Z-axis lifting system 30 are provided on the upper table surfaces and the lower table surfaces on the left and right sides of the main frame structure. Upper bearing seats 31A are respectively installed in the two bearing seat holes 111 located above, and lower bearing seats 31B are respectively installed in the two bearing seat holes 111 located below.

[0050] Referring to Figure 7 , the Z-axis lifting system 30 includes a first transmission lead screw 32 and a second transmission lead screw 33 that are respectively arranged on the left and right sides and are respectively connected to the upper and lower bearing seats on the corresponding sides. Linear guide rails 34 are also fixed on the inner guide rail surfaces on the left and right sides of the main frame structure. A lifting slide table 35 is installed between the two guide rail sliders on the same-side linear guide rail 34. The lifting slide table 35 is connected to the corresponding transmission lead screw and moves by the driving force of the corresponding transmission lead screw; a support seat 36 corresponding to the position of the piston plate support block 24 is installed on the side wall of the lifting slide table facing the forming cylinder. The support seat 36 is in contact with the piston plate support block 24 and supports the piston plate support block 24. The support seat 36 can lift the piston plate 23 upward through the piston plate support block 24, and the descent of the piston plate 23 is achieved by its own gravity; the lower ends of the first transmission lead screw 32 and the second transmission lead screw 33 are respectively connected to a first commutator 37, and the two first commutators 37 are respectively connected to a second commutator 38 located in the middle through a first transmission shaft; the Z-axis lifting drive motor 39 is connected to the second commutator 38 and is connected to the two first commutators 37 on both sides through the first transmission shafts on both sides, so as to drive the transmission lead screws on both sides to rotate simultaneously, and further realize the simultaneous up and down movement of the two lifting slide tables 35, and finally make the piston plate 23 in the forming cylinder 20 move in the Z-axis direction.

[0051] In a further specific embodiment, a sand laying drive system installation plane 112 is provided on the upper table surface of the main frame structure 11. Referring to Figure 8 , the sand laying drive system 40 includes a first drive module 41 and a second drive module 42 that are respectively located on both sides of the narrow side of the square hole in the printing area of the forming cylinder. A second transmission shaft 43 is arranged between the two drive modules. The second transmission shaft 43 is driven to rotate by a sand laying drive motor 44 through a pulley 45 and a transmission belt 46; a conveying belt controlled to rotate by the second transmission shaft 43 is respectively arranged in the two drive modules. Module sliders 47 are installed on the conveying belt. The two drive modules are connected to the second transmission shaft 43 to realize the synchronous operation of the two module sliders 47; the sand laying vehicle 60 is connected to the module slider 47 in the sand laying drive system 40. Driven by the sand laying drive motor 44, the sand laying vehicle 60 can reciprocate along the narrow side direction of the square hole in the printing area of the forming cylinder.

[0052] Further, the sand supply system 50 is fixed to the upper table surface of the main frame structure 11 through the support beam 54. Refer to Figures 9 - 11 , the sand supply system 50 includes a pneumatic sand separator 51, a spiral spreading bin 52, and a indexing blanking bin 53. The feeding pipe 517 of the pneumatic sand separator 51 is connected to the spiral spreading bin inlet in the middle of the top of the spiral spreading bin 52. Along the axial direction in the spiral spreading bin 52, first spiral blades 521 and second spiral blades 522 with equal lengths are arranged. The first spiral blades 521 and the second spiral blades 522 are installed on the same spiral spreading shaft and have opposite spiral directions. The demarcation point between the first spiral blades 521 and the second spiral blades 522 is located at the spiral spreading bin inlet. One end of the spiral spreading shaft is connected to the spiral blade driving motor 523. When the spiral blade driving motor 523 is started, it drives the first spiral blades 521 and the second spiral blades 522 to evenly spread the sand material to both sides. There is a connecting guide bin 55 between the spiral spreading bin 52 and the indexing blanking bin 53, making the spiral spreading bin 52 and the indexing blanking bin 53 communicate with each other.

[0053] An indexing blanking shaft 531 is installed in the indexing blanking bin 53. A number of straight blades 532 are evenly distributed radially on the outer circle of the indexing blanking shaft 531. One end of the indexing blanking shaft 531 is connected to the indexing blanking motor 533. An outlet 534 is provided at the lower end of the indexing blanking bin 53, and the outlet 534 is just higher than the sand spreading vehicle 60. When sand material is needed, the sand spreading vehicle 60 runs to below the outlet 534. The indexing blanking motor 533 is started to drive the indexing blanking shaft 531 to rotate, and the blades 532 push the sand material down and fall into the sand spreading vehicle 60 through the outlet 534.

[0054] The pneumatic sand separator 51 includes a conical cabin 511 connected to the feeding pipe 519 at the upper part. An annular air guide plate 512 is provided at the inlet of the conical cabin 511 and above it. At the same time, a gas outlet is provided at the top of the conical cabin 511. A deceleration plate 513 is provided at the gas outlet. A number of small holes are opened on the deceleration plate 513. A filter element 514 is also installed at the gas outlet above the deceleration plate 513. The outside of the filter element 514 is integrally covered by a protective cover 515, and a number of air outlet holes are opened on the outer peripheral wall of the protective cover 515. A level switch 516 is provided below the inlet of the conical cabin 511, and the level switch 516 is located in the upper middle part of the conical cabin 511. A feeding pipe 517 is provided at the bottom of the conical cabin 511, and a gate 518 is installed at the feeding pipe 517.

[0055] The high-speed airflow blows the sand material into the conical cabin 511 along the feed pipe 519. The sand material first flows along the annular air guide plate 512. The heavy sand material spirally descends along the inner wall of the conical cabin to the bottom of the cabin and gradually piles up. The high-pressure airflow flows upward and passes through the small holes on the deceleration plate 513 and the filter element 514 in sequence (the high-pressure airflow decelerates the airflow through the small holes on the deceleration plate 513 and blocks large sand and dust particles to protect the filter element 514; then the high-pressure airflow is discharged into the atmosphere after filtering the dust through the filter element 514), and finally discharges the conical cabin 511 through the air outlet on the protective cover 515; during the feeding process, when the sand material gradually piles up to the height of the material level switch, the feed pipe 519 stops feeding the conical cabin 511; then the gate 518 is opened, and the sand material is injected into the feed port of the spiral paving bin along the feed pipe 517. At this time, the spiral blade drive motor 523 is started to drive the first spiral blade 521 and the second spiral blade 522 to spread the sand material evenly to both sides.

[0056] In a further specific embodiment, a print drive support 15 is also installed above the upper table surface of the main frame structure 11, and the print drive system 80 includes two groups of print drive modules 81 correspondingly horizontally mounted on the print drive support 15 and a print drive slider 82 correspondingly slidably installed at the bottom of the print drive module 81. The print drive module 81 is a linear motor drive module, and the two print drive sliders 82 achieve motion synchronization through gantry control, and the movement direction of the print drive slider 82 is consistent with the wide side direction of the square hole in the printing area of the forming cylinder; the printing carriage 70 is connected to the two print drive sliders 82, so that the movement direction of the sand laying carriage 60 is perpendicular to the movement direction of the printing carriage 70, and the sand laying carriage 60 and the printing carriage 70 can run alternately to achieve staggered operation of sand laying and printing.

[0057] See also Figure 12 In this embodiment, the workflow of a large-size sand mold 3D printing device in which sand laying and printing are staggered is as follows:

[0058] S1, the sand spreading vehicle 60 moves to the other side of the forming cylinder 20, and then returns to the original position to spread sand, that is, the sand spreading vehicle 60 reciprocates along the narrow side of the square hole in the printing area of the forming cylinder, and then returns to the initial position and stays at one end of the sand supply system 50 to replenish sand;

[0059] S2, the printing carriage 70 completes one printing on the entire surface of the forming cylinder, and then resets to the original position; that is, the printing carriage 70 reciprocates along the wide side of the square hole in the printing area of the forming cylinder, and then returns to the initial position;

[0060] S3, a layer of printing is completed, and then the above sanding printing is repeated until the printing is completed.

[0061] Example 2

[0062] See also Figure 13, in this embodiment, the working process of a large-sized sand mold 3D printing device with interleaved sand laying and printing is as follows:

[0063] S1, the sand laying vehicle 60 runs to the other side of the forming cylinder 20 for sand laying; that is, the sand laying vehicle 60 runs forward along the narrow side direction of the square hole in the printing area of the forming cylinder to one side;

[0064] S2, the printing vehicle 70 completes one printing on the entire surface of the forming cylinder, and then performs a reset movement to the original position; that is, the printing vehicle 70 runs reciprocally along the wide side direction of the square hole in the printing area of the forming cylinder and returns to the initial position;

[0065] S3, the sand laying vehicle 60 returns and runs to the original side of the forming cylinder 20 for sand laying, that is, the sand laying vehicle 60 runs reversely along the narrow side direction of the square hole in the printing area of the forming cylinder, returns to the initial position, and stays at one end of the sand supply system 50 for supplementary sand;

[0066] S4, the printing vehicle 70 completes one printing again on the entire surface of the forming cylinder, and then performs a reset movement to the original position;

[0067] S5, thus completing one reciprocating printing action, and then looping the above sand laying and printing until the printing is completed.

[0068] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and reference can be made to the description in the method part for related parts.

[0069] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A large-sized sand mold 3D printing device with alternating sand laying and printing, characterized in that It includes a main equipment frame, a forming cylinder, a sand spreading drive system, a sand supply system, a sand spreading vehicle, a printing drive system, and a printing vehicle. Among them, the forming cylinder can automatically move in and out of the interior of the main equipment frame. A rectangular hole for the printing area of the forming cylinder is provided in the upper part of the main equipment frame. The printing position of the forming cylinder is located below the rectangular hole for the printing area of the forming cylinder. A piston plate that can move up and down is provided inside the forming cylinder, and the piston area of the forming cylinder corresponds to the rectangular hole for the printing area of the upper part. The sand spreading drive system is arranged along both sides of the narrow edge of the rectangular hole for the printing area of the forming cylinder in the upper part of the main equipment frame. The sand spreading vehicle is controlled by the sand spreading drive system to run along the narrow edge direction of the rectangular hole for the printing area of the forming cylinder. The sand supply system is arranged at one end of the sand spreading drive system, and its length direction is parallel to the sand spreading vehicle. The discharge port of the sand supply system is located above the sand spreading vehicle to continuously supply sand material to the sand spreading vehicle. A printing drive system is also provided on the top of the main equipment frame. The printing vehicle is controlled by the printing drive system to run along the wide edge direction of the rectangular hole for the printing area of the forming cylinder. The moving direction of the sand spreading vehicle is perpendicular to the moving direction of the printing vehicle. During operation, the sand spreading vehicle and the printing vehicle run alternately to achieve the alternating actions of sand spreading and printing.

2. The large-sized sand mold 3D printing device with alternating operation of sand spreading and printing according to claim 1, wherein, The exterior of the forming cylinder is a rectangular cylinder composed of four side cylinder plates and one cylinder bottom plate. Taking the moving direction of the forming cylinder as the front-back direction, vertically long strip-shaped holes are symmetrically provided on the left side cylinder plate and the right side cylinder plate of the forming cylinder. The piston plate is adapted to the inner cavity shape of the rectangular cylinder, and piston plate sealing strips that are in close contact with the inner wall of the rectangular cylinder are evenly arranged around the piston plate. Piston plate support blocks are respectively connected to the bottom surfaces of the two symmetric sides of the piston plate left and right. The connection positions of the piston plate support blocks correspond to the vertically long strip-shaped holes of the side cylinder plates. The piston plate support blocks can extend out of the rectangular cylinder from the vertically long strip-shaped holes of the side cylinder plates and move up and down within the range of the vertically long strip-shaped holes of the side cylinder plates along with the piston plate. An installation space is left between the piston plate support blocks and the piston plate above them. In the installation space, a pressure belt wheel and a guide wheel that are rotationally connected to the bottom surface of the piston plate are arranged side by side left and right, and the pressure belt wheel is closer to the vertically long strip-shaped hole of the side cylinder plate. On the left and right inner walls of the rectangular cylinder, a sealing steel belt is arranged along the vertically long strip-shaped hole of the side cylinder plate respectively. The width of the sealing steel belt is greater than the width of the vertically long strip-shaped hole of the side cylinder plate and can completely cover the vertically long strip-shaped hole of the side cylinder plate. The upper end of each sealing steel belt is fixed to the upper end surface of the corresponding side cylinder plate through a sealing steel belt fixing block. The sealing steel belt passes downward through the gap between the piston plate sealing strip and the inner wall of the corresponding rectangular cylinder and sequentially passes through the corresponding pressure belt wheel and guide wheel in an S shape. At the same time, the pressure belt wheel tightly presses the sealing steel belt against the corresponding side cylinder plate. The lower end of the sealing steel belt is connected to the corresponding sealing steel belt tensioning mechanism below.

3. The large-sized sand mold 3D printing device with staggered operation of sand spreading and printing according to claim 2, characterized in that, The sealing steel belt tensioning mechanism is fixed on the cylinder bottom plate and is on a vertical line with the corresponding side cylinder plate elongated hole and the piston plate support block; the sealing steel belt tensioning mechanism includes a fixing frame installed on the cylinder bottom plate, a slider seat is installed on the outer wall of the fixing frame facing the side cylinder plate elongated hole, two vertical guide shafts are fixed side by side on both sides of the slider seat, and an adjustment slider, a spring and a tensioning slider are installed on the guide shaft from top to bottom in sequence; the adjusting bolt passes through the slider seat and the adjusting slider downward from the middle of the upper end face of the slider seat, and is threadedly connected to the adjusting slider; a steel belt fixing plate for fixing the lower end of the sealing steel belt is installed on the outer wall of the tensioning slider facing the side cylinder plate elongated hole.

4. A large-sized sand mold 3D printing device with alternating sand spreading and printing as claimed in claim 2 or 3, characterized in that, The main frame of the equipment includes a main frame structure, and two track wheel groups are installed in parallel on both sides of the inner bottom plate of the main frame structure. All the track wheels in each track wheel group are connected in series by a track wheel transmission chain. A track wheel drive motor is installed under the inner bottom plate of the main frame structure between the two track wheel groups. The track wheel drive motor is connected to the drive shafts on both sides and controls the drive shafts to drive the track wheels on both sides to rotate synchronously. The forming cylinder is placed on the two track wheel groups and can enter and exit the main frame of the equipment along the movement direction of the track wheels under the rolling friction of the track wheels.

5. A large-sized sand mold 3D printing device with alternating sand spreading and printing according to claim 4, characterized in that, It also includes a Z-axis lifting system that provides Z-axis movement drive for the piston plate in the forming cylinder. The Z-axis lifting system is located inside the main frame structure. The upper table and the lower table on the left and right sides of the main frame structure are provided with bearing seat holes for installing the Z-axis lifting system. The upper bearing seats are installed in the two upper bearing seat holes respectively, and the lower bearing seats are installed in the two lower bearing seat holes respectively; the Z-axis lifting system includes a first transmission screw and a second transmission screw that are respectively arranged on the left and right sides and connected to the upper and lower bearing seats on the corresponding sides, and linear guides are also fixed on the internal guide surfaces on the left and right sides of the main frame structure. A lifting slide is installed between the two guide sliders on the linear guide on the same side, and the lifting slide is connected to the transmission screw on the corresponding side, and is driven and moved by the corresponding transmission screw; a support seat corresponding to the position of the piston plate support block is installed on the side wall of the lifting slide facing the forming cylinder; the lower ends of the first transmission screw and the second transmission screw are each connected to a first commutator, and the two first commutators are respectively connected to the second commutator located in the middle through the first transmission shaft, and the Z-axis lifting drive motor is connected to the second commutator.

6. The large-size sand mold 3D printing device with staggered operation of sand spreading and printing according to claim 4, characterized in that, A sand-laying drive system installation plane is provided on the upper table surface of the main frame structure. The sand-laying drive system includes a first drive module and a second drive module respectively located on both sides of the narrow side of the square hole in the printing area of the forming cylinder. A second transmission shaft is provided between the two drive modules, and the second transmission shaft is driven to rotate by a sand-laying drive motor through a pulley and a transmission belt; each of the two drive modules is provided with a conveyor belt controlled to rotate by the second transmission shaft, and a module slider is installed on the conveyor belt. The two drive modules are connected to the second transmission shaft to realize synchronous operation of the two module sliders; the sand-laying cart is connected to the module slider in the sand-laying drive system, and driven by the sand-laying drive motor, the sand-laying cart can reciprocate along the narrow side of the square hole in the printing area of the forming cylinder.

7. A large-sized sand mold 3D printing device with alternating sand spreading and printing as claimed in claim 6, characterized in that, The sand supply system is fixed to the upper surface of the main frame structure through a support beam. The sand supply system includes a pneumatic sand separator, a spiral leveling bin, and a indexing blanking bin. The discharge pipe of the pneumatic sand separator is connected to the spiral leveling bin inlet in the middle of the top of the spiral leveling bin. Along the axial direction in the spiral leveling bin, there are first spiral blades and second spiral blades with equal lengths. The first spiral blade and the second spiral blade are installed on the same spiral leveling shaft and have opposite spiral directions. The demarcation point between the first spiral blade and the second spiral blade is located at the spiral leveling bin inlet. One end of the spiral leveling shaft is connected to the spiral blade drive motor; there is a connecting guide bin between the spiral leveling bin and the indexing blanking bin to connect the spiral leveling bin and the indexing blanking bin to each other.

8. A large-sized sand mold 3D printing device with alternating sand spreading and printing as claimed in claim 7, characterized in that, An indexing blanking shaft is installed in the indexing blanking bin. A number of blades are evenly distributed radially on the outer circle of the indexing blanking shaft. One end of the indexing blanking shaft is connected to the indexing blanking motor; a discharge port is provided at the lower end of the indexing blanking bin.

9. A large-sized sand mold 3D printing device with alternating operation of sand spreading and printing according to claim 8, characterized in that, The pneumatic sand separator includes a conical cabin connected to the inlet pipe at the upper part. An annular air guide plate is provided at the inlet of the conical cabin and above it. At the same time, a gas outlet is provided at the top of the conical cabin. A deceleration plate is provided at the gas outlet. A number of small holes are opened on the deceleration plate. A filter element is also installed at the gas outlet above the deceleration plate. The outside of the filter element is integrally covered by a protective cover. A number of air outlet holes are opened on the outer peripheral wall of the protective cover; a level switch is provided below the inlet of the conical cabin, and the level switch is located in the upper middle part of the conical cabin; a discharge pipe is provided at the bottom of the conical cabin, and a gate is installed at the discharge pipe.

10. A large-sized sand mold 3D printing device with alternating sand spreading and printing operations according to claim 4, characterized in that, Above the upper surface of the main frame structure, a printing drive support is also installed. The printing drive system includes two groups of printing drive modules horizontally arranged corresponding to the printing drive support and printing drive sliders slidably installed corresponding to the bottom of the printing drive modules. The printing drive module is a linear motor drive module. The two printing drive sliders achieve synchronous movement through gantry control, and the movement direction of the printing drive sliders is consistent with the long side direction of the square hole in the printing area of the forming cylinder; The printing carriage is connected to the two printing drive sliders, so that the movement direction of the sand spreading carriage is perpendicular to the movement direction of the printing carriage.

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