Bidirectional sanding device of 3D printer

Abstract

The invention relates to the field of sand mold 3D printers, in particular to a 3D printer two-way sand paving device which comprises a sand conveying device, a vibration device, a main sand scraping plate, an auxiliary sand scraping plate and a sand discharging plate which are arranged on a sand paving device cross beam, the sand conveying device fills a sand storage bin with sand entering from a sand adding opening, and the main sand scraping plate and the sand discharging plate are arranged in a staggered mode. After sand falls from the sand storage bin, a sand stacking slope is formed between the sand discharging plate and the main sand scraping plate, the vibration device drives the sand storage bin, the main sand scraping plate and the auxiliary sand scraping plate to vibrate through vibration to achieve uniform sand paving, and a connecting assembly is arranged between the main sand scraping plate and the auxiliary sand scraping plate. According to the bidirectional sand paving printing device of the 3D printer, the structure is simple, cleaning is convenient, rapid bidirectional sand paving is achieved under the condition that one sand discharging opening is used, the sand paving efficiency is doubled compared with one-way sand paving, the sand surface is rapidly solidified in combination with the heating device, the overall printing speed is increased, and the printing efficiency is improved. And meanwhile, the situation that printed products are poor due to insufficient curing can be reduced, and the percent of pass of the printed products is comprehensively improved.

Description

Technical Field

[0001] The present invention relates to the field of sand mold 3D printers, and particularly to a two-way sand spreading device for a 3D printer. Background Art

[0002] Currently, the conventional sand spreaders used in 3D printing equipment are roughly divided into three types. The first is a unidirectional sand spreader, which has low printing efficiency. The second is a two-way sand spreader with two lower sand outlets. It can achieve two-way sand spreading, but with two lower sand outlets and two sets of vibration mechanisms. During the two-way sand spreading process, the two lower sand outlets and the two sets of vibration mechanisms work alternately. This structure is complex and occupies a large space, and there are a series of problems such as no sand falling, sand leakage, and uneven sand falling. The third is a single lower sand outlet two-way sand spreader, but it uses a double-layer lower sand outlet, with a complex structure and difficult equipment maintenance. Once the lower sand outlet is blocked due to foreign objects or sand caking during the cleaning process during printing, due to the difficulty of cleaning, it will cause a series of problems such as no sand falling and uneven sand falling, ultimately affecting the printing quality. Summary of the Invention

[0003] The purpose of the present invention is to provide a two-way sand spreading device for a 3D printer to solve the above-mentioned deficiencies of the prior art, which can achieve two-way sand spreading, solve the technical problems of sand leakage and uneven sand falling, and improve the printing efficiency.

[0004] The two-way sand spreading device for a 3D printer includes a sand conveying device, a vibration device, a main sand scraping plate, a secondary sand scraping plate, and a lower sand plate provided on the cross beam of the sand spreading device. The sand conveying device is provided with a sand storage bin. The sand material enters from the sand adding port, and the sand conveying device fills the sand storage bin with the sand material entering from the sand adding port. The sand storage bin can be arranged inside the sand conveying device or inside the vibration device. The main sand scraping plate and the lower sand plate are arranged alternately. The vibration device drives the lower sand plate and the main sand scraping plate to vibrate together, so that a sand pile slope is formed between the lower sand plate and the main sand scraping plate. As the vibration continues, the sand material falls from the lower sand outlet to achieve uniform sand falling, and the sand spreading is completed under the action of the main sand scraping plate and the secondary sand scraping plate. The vibration device drives the main sand scraping plate, the secondary sand scraping plate, and the lower sand plate to vibrate and spread sand. As the cross beam of the sand spreading device reciprocates, two-way sand spreading can be achieved.

[0005] Further, the vibration device includes a motor, a vibration shaft, and a plurality of eccentric wheels. The inner ring of the eccentric wheel is fixedly connected to the vibration shaft. The motor is connected to the vibration shaft to drive the eccentric wheel to rotate through the vibration shaft. The outer ring of the eccentric wheel is connected to one end of a movable connecting rod, and the other end of the movable connecting rod is hinged to a rocker through a movable rotating shaft. The rocker is connected to the main sand scraping plate and the secondary sand scraping plate to drive the main sand scraping plate and the secondary sand scraping plate to vibrate reciprocally when the eccentric wheel rotates. The vibration shaft drives a plurality of eccentric wheels to rotate simultaneously, which can make the vibration consistency of the main sand scraping plate and the secondary sand scraping plate higher, facilitating uniform sand spreading.

[0006] Further, the multiple eccentric wheels are evenly distributed in the length direction of the vibration shaft, and the distance between two adjacent eccentric wheels is 400-500 mm, which can make the amplitudes of the main sand scraping plate and the secondary sand scraping plate uniform and the vibration synchronous, and can enhance the overall rigidity of the vibration device and extend the service time.

[0007] Further, the motor speed is set to 4000-5000 r / min, and the amplitude of the reciprocating vibration of the main sand scraping plate and the secondary sand scraping plate driven by the rocker is 0.05-0.1 mm. In this speed range, the motor can not only achieve rapid sand discharging and sand spreading, but also achieve uniformity, and will not cause uneven sand discharging and sand spreading due to too fast or too slow speed; the motor speed, that is, the vibration frequency of the vibration device, is directly proportional to the sand discharging amount. The secondary sand scraping plate reciprocates within a range of 0.05-0.1 mm in height, which can avoid damaging the printed sand surface due to too large amplitude during the sand spreading process.

[0008] The connection assembly between the main sand scraping plate and the secondary sand scraping plate includes: a main sand scraping plate cross beam connected to the main sand scraping plate, a secondary sand scraping plate cross beam connected to the secondary sand scraping plate, a secondary sand scraping plate support plate, and a connecting rod; one end of the main sand scraping plate cross beam is connected to one end of the secondary sand scraping plate support plate, and the other end of the secondary sand scraping plate support plate is fixedly connected to the secondary sand scraping plate cross beam and the secondary sand scraping plate through the connecting rod. The other end of the main sand scraping plate cross beam is connected to the rocker, and the rocker is fixedly connected to the main sand scraping plate cross beam. The main sand scraping plate cross beam is hinged to the fixed connecting rod through a fixed rotating shaft, so as to realize the simultaneous reciprocating vibration of the main sand scraping plate and the secondary sand scraping plate driven by the rocker. The connection assembly can balance the amplitude consistency between the main sand scraping plate and the secondary sand scraping plate, so as to make the sand discharging and sand spreading more uniform.

[0009] Further, there are multiple connecting rods between the main sand scraping plate and the secondary sand scraping plate, which are arranged at intervals along the length direction of the main sand scraping plate and the secondary sand scraping plate, and the interval distance is 100-250 mm. Setting the connecting rod within the interval distance can improve the rigidity of the main sand scraping plate and the secondary sand scraping plate, and make the amplitudes and vibration frequencies of the two sand scraping plates consistent.

[0010] Furthermore, the contact part of the main sand scraping plate and the sand laying surface is a rounded corner of the main sand scraping plate. The line connecting the center of the rounded corner of the main sand scraping plate and the axis of the fixed rotating shaft forms a first angle with the vertical direction; the contact part of the secondary sand scraping plate and the sand laying surface is a rounded corner of the secondary sand scraping plate. The line connecting the center of the rounded corner of the secondary sand scraping plate and the axis of the fixed rotating shaft forms a second angle with the vertical direction; the first angle and the second angle are the same, so as to ensure the same amplitude of the main and secondary sand scraping plates. During the sand laying process, the amplitudes of the main and secondary sand scraping plates are the same, and the beating amplitudes of each layer of sand surface are the same, so that the compactness of each layer of sand surface can be made consistent, and further the strength of the finally formed sand mold is uniform.

[0011] The two-way sand laying device of the 3D printer further includes a heating device. The heating device includes a heating rod and a protective cover. The heating rod is 20-30 mm away from the sand laying surface in the height direction, and the temperature of the heating rod is set at 35-40 °C. The heating rod can accelerate the curing of the printed sand surface within the height and temperature ranges. The protective cover can protect the heating rod from damage caused by sand and gravel during the sand laying process of the main and secondary sand scraping plates due to vibration. The length of the heating rod should be greater than or equal to the effective sand laying length to accelerate the curing of the printed sand surface.

[0012] The main sand scraping plate and the secondary sand scraping plate are respectively provided with an inclination angle of 0.3-0.5° relative to the sand laying surface. At the same time, the contact parts of the main sand scraping plate and the secondary sand scraping plate with the sand laying surface adopt a rounded corner transition design. By combining the inclination angle and the rounded corner design of the main sand scraping plate and the secondary sand scraping plate, and the consistency design of various parameters of the main and secondary sand scraping plates, it can be ensured that the sand laying thickness in the forward and reverse directions is the same, and the sand pushing phenomenon during the sand laying process can be effectively reduced.

[0013] The bottom of the sand feeding plate has a folded corner part, which is parallel to the sand laying surface. The folded corner part and the main sand scraping plate are vertically staggered, so that the sand material forms a sand pile inclined plane between the folded corner part and the main sand scraping plate; no sand will fall during the non-working state, thereby reducing the sand loss of the sand laying device.

[0014] The sand feeding plate is provided with an adjustment hole. The adjustment nut passes through the adjustment hole to fix the sand feeding plate on the sand laying device and adjust the height of the sand feeding plate; by adjusting the height of the sand feeding plate, the sand feeding speed can be adjusted according to different types of sand materials and adapted to the sand feeding speed according to the printed product.

[0015] The included angle between the sand pile inclined plane between the sand feeding plate and the main sand scraping plate and the sand scraping surface of the main sand scraping plate is 25-35°. If the included angle is too small, the sand will slide off even when the vibration device is not vibrating, causing sand leakage. If the included angle is too large, the sand feeding will be uneven when the vibration device is working.

[0016] In summary, the 3D printer two-way sand spreading printing device adopting the above technical solution has a simple structure and is easy to clean. It realizes rapid two-way sand spreading with one lower sand outlet. Compared with one-way sand spreading, the sand spreading efficiency is doubled. Combined with the heating device, it quickly cures the sand surface, improves the overall printing speed, and at the same time can reduce the occurrence of defects in the printed product caused by insufficient curing, comprehensively improving the qualification rate of the printed product. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the accompanying drawings required for use in the embodiments will be briefly introduced below.

[0018] It should be understood that the following accompanying drawings only show some embodiments of the present disclosure and not all of them, and therefore should not be regarded as limiting the scope.

[0019] It should be understood that the same or similar reference numerals are used to represent the same or similar elements in the accompanying drawings.

[0020] It should be understood that the accompanying drawings are only schematic, and the sizes and proportions of the elements in the accompanying drawings are not necessarily accurate.

[0021] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0022] Figure 2 It is a schematic diagram of the positional relationship of the main devices of the present invention.

[0023] Figure 3 It is a schematic diagram of the structure of the vibration device of the present invention.

[0024] Figure 4 It is a schematic sectional view of the mechanism of the present invention.

[0025] Figure 5 It is a diagram of the positional relationship of the main components of the present invention.

[0026] Figure 6 It is a schematic diagram of the main and auxiliary sand scraping plates of the present invention.

[0027] Figure 7 It is a schematic diagram of the positional relationship between the lower sand plate and the lower sand outlet of the present invention.

[0028] Figure 8 It is a schematic diagram of the positional relationship between the cross beam of the main sand scraping plate and the rocker of the present invention.

[0029] Reference numerals: 1 - heating device; 12 - heating rod; 13 - protective cover; 2 - sand feeding device; 21 - sand adding port; 22 - cross beam of sand spreading device; 23 - sand storage bin; 3 - vibrating device; 31 - vibrating shaft; 32 - eccentric wheel; 33 - motor; 34 - movable connecting rod; 35 - movable rotating shaft; 36 - rocker; 38 - fixed connecting rod; 39 - fixed rotating shaft; 4 - main sand scraping plate; 41 - rounded corner of main sand scraping plate; 42 - rounded corner of secondary sand scraping plate; 43 - cross beam of main sand scraping plate; 44 - angle between main sand scraping plate and sand spreading surface; 45 - angle between secondary sand scraping plate and sand spreading surface; 46 - axis center; 47 - first angle; 48 - second angle; 5 - secondary sand scraping plate; 51 - connecting rod; 52 - supporting plate of secondary sand scraping plate; 53 - cross beam of secondary sand scraping plate; 6 - sand discharging plate; 61 - angle of sand discharging plate; 62 - sand discharging port; 63 - adjusting nut; 7 - sand spreading surface. Detailed implementation manners

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] As Figure 1 、 Figure 2 shown, in the embodiment of the present invention, the 3D printer two-way sand spreading device includes a heating device 1, a sand feeding device 2, a vibrating device 3, a main sand scraping plate 4, a secondary sand scraping plate 5, a sand discharging plate 6, etc. The sand feeding device 2 is arranged on the cross beam 22 of the sand spreading device; the mixed sand enters the sand feeding device 2 through the sand adding port 21, and the sand is spread over the entire sand storage bin 23 through the conveying shaft in the sand feeding device 2. The sand storage bin 23 can be arranged inside the sand feeding device 2 or inside the vibrating device 3.

[0032] The heating device 1 moves synchronously with the sand spreading device. The heating device 1 includes a heating rod 12 and a protective cover 13; the height of the heating rod 12 from the sand spreading surface 7 is 20 - 30 mm, and the temperature of the heating rod is 35 - 40 °C, which heats the sand surface in real time to promote the solidification of the sand mold. If the temperature is too low, the sand surface will not solidify in time. When printing the lower layer, due to the higher humidity of the upper sand surface, the sand scraping plate will affect the upper layer. If the temperature is too high, the sand surface has solidified, and when printing the lower layer, there will be layer lines in the adhesion with the upper layer, affecting the appearance quality.

[0033] As Figure 3 、 Figure 4 、 Figure 5As shown, the vibration device 3 is started, and the sand material in the sand storage bin 23 falls, and finally is output through the lower sand outlet to the sand spreading surface. The vibration device 3 can drive the vibration shaft 31 to rotate at a high speed through the motor 33. A plurality of eccentric wheels 32 are installed at intervals on the vibration shaft, and the vibration device 3 makes periodic reciprocating swings. The plurality of eccentric wheels 32 are evenly spaced in the length direction of the vibration shaft 31, and the distance between two adjacent eccentric wheels 32 can be set between 400 and 500 mm.

[0034] The vibration shaft 31 is fixedly connected to the inner rings of the plurality of eccentric wheels 32. One end of the movable connecting rod 34 is connected to the outer ring of the eccentric wheel 32, and the other end is hinged to the rocker 36 using the movable rotating shaft 35; as Figure 8 shown, the rocker 36 is fixedly connected to the main scraping plate cross beam 43. The main scraping plate cross beam 43 is hinged to the fixed connecting rod 38 through the fixed rotating shaft 39, and the fixed connecting rod 38 is fixed on the device cross beam 22; one end of the auxiliary scraping plate support plate 52 is connected to the main scraping plate cross beam 43, and the other end is fixedly connected to the auxiliary scraping plate cross beam 53 and the auxiliary scraping plate 5 through the connecting rod 51. Among them, the above-mentioned main scraping plate cross beam 43, auxiliary scraping plate support plate 52, auxiliary scraping plate cross beam 53 and connecting rod 51, etc. form the connection assembly between the main scraping plate 4 and the auxiliary scraping plate 5.

[0035] When the eccentric wheel 32 rotates, it drives the rocker 36 to swing through the movable connecting rod 34. Since the rocker 36, the main scraping plate cross beam 43, the main scraping plate 4, the auxiliary scraping plate support plate 52, the connecting rod 51, the auxiliary scraping plate cross beam 53 and the auxiliary scraping plate 5 are connected as a whole, the main scraping plate 4 and the auxiliary scraping plate 5 etc. vibrate reciprocally together. The amplitude can be set to 0.05 - 0.1 mm, and the rotational speed of the motor 33 is set to 4000 - 5000 r / min. Through this synchronous and regular vibration, the balance of the sand in the vibration device is broken to achieve sand discharging; by changing the amplitude and vibration frequency, the sand discharging amount can be changed. However, if the amplitude is too large, there is a risk of damaging the printed surface of the upper layer; if the vibration frequency is too high, it will increase the wear of the mechanism and reduce the service life. Therefore, a larger amplitude or an increased vibration frequency can be selected within a reasonable range.

[0036] To ensure that the parameters of the main scraping plate 4 and the auxiliary scraping plate 5, such as amplitude, vibration frequency, vibration height, etc. are consistent during high-frequency vibration, the main and auxiliary scraping plates must have sufficient strength. As Figure 6 shown, there can be multiple connecting rods 51 between the auxiliary scraping plate 5 and the main scraping plate 4; each connecting rod 51 is arranged at intervals along the length directions of the main scraping plate 4 and the auxiliary scraping plate 5, and the interval distance can be set between 100 and 250 mm. For example, a connecting rod 51 can be set every 200 mm to ensure the reliable and firm connection of the main and auxiliary scraping plates, and further ensure the consistency of the parameters of the main and auxiliary scraping plates, so as to ensure that the paving thickness in the forward and reverse directions is the same and the sand mold cures evenly.

[0037] The main scraping plate 4 and the auxiliary scraping plate 5 are respectively provided with an inclination angle of 0.3 - 0.5° relative to the sand-laying surface 7, as Figure 6 shown by the included angle 44 between the main scraping plate and the sand-laying surface and the included angle 45 between the auxiliary scraping plate and the sand-laying surface; at the same time, the contact parts of the main scraping plate 4 with the sand-laying surface 7 and the contact parts of the auxiliary scraping plate 5 with the sand-laying surface 7 both adopt a rounded corner transition design, as Figure 6 shown by the main scraping plate rounded corner 41 and the auxiliary scraping plate rounded corner 42. The combination of these two designs can effectively reduce the sand-pushing phenomenon. In addition, the connection line between the center 46 of the main scraping plate rounded corner 41 and the fixed rotating shaft 39 forms a first included angle 47 with the vertical direction, and the connection line between the center 46 of the auxiliary scraping plate rounded corner 42 and the center 46 forms a second included angle 48 with the vertical direction. The sizes of the first included angle 47 and the second included angle 48 should be ensured to be the same in the design. The purpose of this design is to ensure that the amplitudes of the main and auxiliary scraping plates are the same. During the sand-laying process, only when the amplitudes of the main and auxiliary scraping plates are the same, the beating amplitudes of each layer of sand surface are the same, so that the compactness of each layer of sand surface is the same, and the strength of the finally formed sand mold is uniform.

[0038] As Figure 7 or Figure 5 shown, the bottom of the lower sand plate 6 has a folded corner part, the folded corner part is parallel to the sand-laying surface, and the folded corner part and the main scraping plate 4 are arranged vertically staggered; the end of the folded corner part is called the lower end part of the lower sand plate 6, and the lower end part of the lower sand plate 6 and the right end part of the main scraping plate 4 close to the lower sand outlet 62 are arranged horizontally staggered; the above vertical and horizontal staggered arrangement forms the lower sand outlet 62; the passage between the sand storage bin 23 and the lower sand outlet 62 is called the lower sand passage. During the process that the sand material falls from the sand storage bin 23 through the lower sand passage and the lower sand outlet 62 to the sand-laying surface 7 finally, a slope can be formed between the lower sand plate 6 and the main scraping plate 4, that is, the sand-piling slope; the included angle between the sand-piling slope and the scraping surface of the main scraping plate is Figure 7 shown as the included angle 61 of the lower sand plate. Among them, the scraping surface of the main scraping plate is the upper surface of the main scraping plate 4, which is used to carry the piled sand material. The included angle 61 of the lower sand plate is the static angle formed by the sand between the lower sand plate 6 and the main scraping plate 4, that is, the inclination angle of the sand-piling slope, which can realize uniform sand falling during vibration and no sand falling when not vibrating. As Figure 7 shown, the included angle 61 of the lower sand plate can also be expressed as the included angle between the connection line between the lower end part of the lower sand plate 6 and the right end part of the main scraping plate 4 and the upper surface of the main scraping plate 4. Therefore, the angle of the included angle 61 of the lower sand plate can be adjusted by adjusting the relative positions of the lower sand plate 6 and the main scraping plate 4; for example, the included angle 61 of the lower sand plate can be set between 25 - 35°.

[0039] The uniformity of the lower sand outlet is very important because the size of the lower sand outlet directly affects the amount of sand flowing out. For convenient adjustment, an adjusting nut 63 is provided. The adjusting nut 63 passes through the adjusting hole provided on the lower sand plate 6, and the height at which the lower sand plate 6 is fixed to the sand laying device can be adjusted, thereby controlling the size of the lower sand outlet 62. When changing the type of sand or adjusting the thickness of the sand laying layer, the height of the lower sand plate 6 is adjusted by the adjusting nut 63 to adjust the size of the lower sand outlet 62 and the included angle 61 of the lower sand plate, and then the adjustment of the amount of sand flowing out is realized. The structure is simple and the adjustment is convenient.

[0040] The basic principles of the present disclosure have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, advantages, effects, etc. mentioned in the present disclosure are only examples and not limitations, and it cannot be considered that these advantages, advantages, effects, etc. are essential for each embodiment of the present disclosure. In addition, the above-mentioned specific details are only for the purpose of illustration and easy understanding, rather than limitations. The above details do not limit the present disclosure to necessarily adopt the above specific details to be implemented.

[0041] The components and devices involved in the present disclosure are only illustrative examples and do not intend to require or imply that they must be connected, arranged, and configured in the manner shown in the drawings. As those skilled in the art will recognize, these components and devices can be connected, arranged, and configured in any way.

[0042] The above is only the specific implementation manner of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present disclosure can easily think of changes or substitutions, which should all be covered within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. A two-way sand spreading device for a 3D printer, characterized in that, Including: A sand conveying device (2), a vibration device (3), a main sand scraping plate (4), a secondary sand scraping plate (5), a sand discharging plate (6), and a sand storage bin (23) provided on the cross beam (22) of the sand spreading device; The sand conveying device (2) spreads the sand material entering from the sand adding port (21) over the sand storage bin (23); the main sand scraping plate (4) and the sand discharging plate (6) are arranged alternately, so that after the sand material falls from the sand storage bin (23), a sand accumulation inclined plane is formed between the sand discharging plate (6) and the main sand scraping plate (4); The vibration device (3) realizes uniform sand spreading by driving the sand discharging plate (6), the main sand scraping plate (4), and the secondary sand scraping plate (5) to vibrate; a connecting component is arranged between the main sand scraping plate (4) and the secondary sand scraping plate (5).

2. The two-way sand spreading device of the 3D printer according to claim 1, wherein The vibration device (3) includes a motor (33), a vibration shaft (31), and a plurality of eccentric wheels (32); The inner ring of the eccentric wheel (32) is fixedly connected to the vibration shaft (31); the motor (33) is connected to the vibration shaft (31) to drive the eccentric wheel (32) to rotate through the vibration shaft (31); The outer ring of the eccentric wheel (32) is connected to one end of a movable connecting rod (34), and the other end of the movable connecting rod (34) is hinged to a rocker (36) using a movable rotating shaft (35), and the rocker (36) is connected to the main sand scraping plate (4) and the secondary sand scraping plate (5) to drive the main sand scraping plate (4) and the secondary sand scraping plate (5) to vibrate reciprocally when the eccentric wheel (32) rotates.

3. The bidirectional sand spreading device of the 3D printer according to claim 2, wherein, The plurality of eccentric wheels (32) are evenly distributed in the length direction of the vibration shaft (31), and the distance between adjacent two eccentric wheels (32) is 400 - 500 mm; the rotational speed of the motor (33) is set to 4000 - 5000 r / min, and the amplitude of the reciprocating vibration of the rocker (36) driving the main sand scraping plate (4) and the secondary sand scraping plate (5) is 0.05 - 0.1 mm.

4. The two-way sand spreading device of the 3D printer according to claim 2, characterized in that, The connecting component between the main sand scraping plate (4) and the secondary sand scraping plate (5) includes: a main sand scraping plate cross beam (43) connected to the main sand scraping plate (4), a secondary sand scraping plate cross beam (53) connected to the secondary sand scraping plate (5), a secondary sand scraping plate support plate (52), and a connecting rod (51); One end of the main sand scraping plate cross beam (43) is connected to one end of the secondary sand scraping plate support plate (52), the other end of the secondary sand scraping plate support plate (52) is fixedly connected to the secondary sand scraping plate cross beam (53) and the secondary sand scraping plate (5) through the connecting rod (51), the other end of the main sand scraping plate cross beam (43) is connected to the rocker (36), the rocker (36) is fixedly connected to the main sand scraping plate cross beam (43), and the main sand scraping plate cross beam (43) is hinged to a fixed connecting rod (38) through a fixed rotating shaft (39) to realize the simultaneous reciprocating vibration of the main sand scraping plate (4) and the secondary sand scraping plate (5) driven by the rocker (36).

5. The two-way sand spreading device of the 3D printer according to claim 4, wherein The connecting rod (51) includes a plurality of them, which are arranged at intervals along the length direction of the main sand scraping plate (4) and the secondary sand scraping plate (5), and the interval distance is 100 - 250 mm.

6. The two-way sand spreading device of the 3D printer according to claim 4, characterized in that The contact part of the main scraping plate (4) and the sand spreading surface (7) is the rounded corner of the main scraping plate (41). The connection line between the rounded corner of the main scraping plate (41) and the axis (46) of the fixed rotating shaft (39) forms a first included angle (47) with the vertical direction; The contact part of the auxiliary scraping plate (5) and the sand spreading surface (7) is the rounded corner of the auxiliary scraping plate (42). The connection line between the rounded corner of the auxiliary scraping plate (42) and the axis (46) of the fixed rotating shaft (39) forms a second included angle (48) with the vertical direction; The first included angle (47) and the second included angle (48) are the same.

7. The two-way sand spreading device of the 3D printer according to claim 1, wherein, The 3D printer two-way sand spreading device further includes a heating device (1); the heating device (1) includes a heating rod (12) and a protective cover (13). The distance between the heating rod (12) and the sand spreading surface (7) is 20 - 30 mm, and the temperature of the heating rod is set to 35 - 40 °C.

8. The two-way sand spreading device of the 3D printer according to claim 1, characterized in that, The main scraping plate (4) and the auxiliary scraping plate (5) are respectively provided with an inclination angle of 0.3 - 0.5° relative to the sand spreading surface (7).

9. The two-way sand spreading device of the 3D printer according to claim 1, characterized in that The bottom of the sand feeding plate (6) has a folding angle part. The folding angle part and the main scraping plate (4) are vertically staggered, so that the sand material forms the sand piling inclined surface between the folding angle part and the main scraping plate (4); the sand feeding plate (6) is provided with an adjusting hole, and an adjusting nut (63) passes through the adjusting hole to fix the sand feeding plate (6) on the sand spreading device and adjust the height of the sand feeding plate (6).

10. The two-way sand spreading device of the 3D printer according to claim 1, characterized in that, The included angle between the sand piling inclined surface and the scraping surface of the main scraping plate (4) is 25 - 35°.

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