A sand spreader and 3D printing apparatus

Abstract

The present application provides a sand spreader, comprising a sand spreader body, a mounting shell, a horizontal moving mechanism, at least one detection piece and a lifting mechanism. By integrating one or more detection pieces onto the sand spreader body, the distance between the detection piece and the detection surface can be measured under the cooperation of the mounting shell, the horizontal moving mechanism and the lifting mechanism, thereby automatically measuring the uniformity of the sand outlet gap of the sand spreader after replacing and installing the scraper, without the need for manual detection, avoiding the error problem caused by manual detection, not only saving manpower, but also improving the accuracy of the detection result, and also ensuring the sanding amount and the uniformity of the sanding, thereby improving the forming effect. The present application also provides a 3D printing equipment comprising the above-mentioned sand spreader.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of 3D printing equipment, and particularly relates to a sand spreader and 3D printing equipment. BACKGROUND

[0002] Sand type 3D printing technology is a sand type additive manufacturing technology combining inkjet printing and traditional resin sand mold forming process. Resin is selectively sprayed on the surface of the sand mixed with curing agent by a nozzle, and the resin and curing agent produce cross-linking reaction, thereby bonding the sand into a specified shape.

[0003] The printing quality and efficiency of the sand type 3D printing equipment depend largely on the sand spreader. The important indicators for measuring the advantages and disadvantages of a sand spreader are the sand discharge amount and the compactness of the spread sand. The width of the sand discharge gap determines the sand discharge amount and the uniformity of the spread sand. Precise control of the width of the sand discharge gap is the basis for ensuring the surface accuracy of the product.

[0004] Referring to Figure 2 For a one-way sand spreader, a first base plate, a second base plate and a scraper are arranged on both sides of the sand discharge gap. The scraper is installed at the bottom of the second base plate. When the sand type 3D printing equipment prints a product, the sand spreader usually spreads sand for 1500 to 2000 layers. After a long time of sand spreading, the position of the scraper may deviate. At the same time, the vibration mechanism drives the scraper to vibrate at a high frequency, thereby flattening and compacting the sand. Therefore, the high-frequency vibration also causes the position of the scraper to deviate. In addition, when the scraper is installed on the second base plate, the position of the scraper also needs to be detected.

[0005] The above problems may cause a certain deviation in the uniformity of the sand discharge gap. Therefore, whether the width of the sand discharge gap of the sand spreader is uniform needs to be checked repeatedly by maintenance personnel. The maintenance personnel adjusts the tightness of the bolts of the scraper corresponding to the detection points, thereby slightly adjusting the position of the scraper. However, the above detection method is time-consuming and labor-intensive, and the detection accuracy also has certain problems. SUMMARY

[0006] In view of the defects in the prior art, the present application aims to provide a sand spreader and 3D printing equipment to realize automatic measurement of the uniformity of the sand discharge gap and improve the accuracy of the detection results.

[0007] In order to achieve the above object, the present application provides a sand spreader, comprising a sand spreader body, a first base plate and a scraper plate arranged at the bottom of the sand spreader body, the bottom surface of the scraper plate being arranged at a lower level than the bottom surface of the first base plate, a first reference surface being formed on the side wall of the first base plate facing the scraper plate, and a detection surface being formed on the side wall of the scraper plate facing the first reference surface; a mounting shell arranged on the sand spreader body, the bottom of the mounting shell being provided with an openable and closable opening, the level of the opening being higher than the level of the first base plate; a transverse moving mechanism for driving the mounting shell to move along the length direction of the sand spreader body; at least one detection piece vertically and movably arranged in the mounting shell, the detection piece being used for detecting the distance between the detection piece and the detection surface; and a lifting mechanism for driving the detection piece to move up and down, so that the detection piece extends out of the opening or retracts into the mounting shell.

[0008] Preferably, the lifting mechanism comprises a lifting driving assembly and at least one lifting guide assembly, the number of the lifting guide assemblies corresponding to the number of the detection pieces; the lifting guide assembly comprises a first sliding rail, a first sliding seat, a connecting rod and a bracket, the first sliding rail being vertically arranged in the mounting shell, the first sliding seat being slidingly arranged on the first sliding rail, the connecting rod being arranged on the first sliding seat, the bracket being arranged at the bottom of the connecting rod, and the detection piece being arranged on the bracket; the lifting driving assembly is used for driving all the first sliding seats to move up and down synchronously.

[0009] Preferably, a plurality of detection pieces are arranged, and the plurality of detection pieces are arranged at intervals along the length direction of the sand spreader body.

[0010] Preferably, the lifting driving assembly comprises a plurality of driving units, each of the driving units comprising an electric push rod and a connecting arm, the electric push rod being vertically arranged between two adjacent first sliding rails, and the telescopic rod of the electric push rod being arranged downward; the connecting arm is connected with the telescopic rod of the electric push rod, and two ends of the connecting arm are respectively connected with two adjacent first sliding seats.

[0011] Preferably, the sand spreader further comprises a cover plate and a locking assembly, the cover plate being capable of covering the opening, and the locking assembly being used for locking the cover plate on the mounting shell or separating the cover plate from the mounting shell.

[0012] Two sides of the cover plate are respectively provided with a first gap, the locking assembly comprises two locking units, the two locking units are arranged on two sides of the mounting shell respectively, and the locking unit comprises: a mounting support arranged on the side wall of the mounting shell; a support shaft rotatably arranged in the mounting support; a threaded rod arranged on the support shaft, the threaded rod can be rotated into the first gap; and a locking hand wheel threadedly arranged on the threaded rod, the locking hand wheel is provided with a fastening part, and when the threaded rod is rotated into the first gap, the fastening part can abut against the bottom surface of the cover plate.

[0013] Preferably, the two side walls of the mounting shell are respectively provided with an ear, the bottom surface of the ear is flush with the bottom surface of the mounting shell, the ear is provided with a second gap for the threaded rod to rotate into, and when the threaded rod is rotated into the second gap, the fastening part can abut against the bottom surface of the ear.

[0014] Preferably, the horizontal moving mechanism comprises a second sliding rail, a second sliding seat, a rack, a motor and a gear, the second sliding rail and the rack are arranged on the side of the sanding machine body facing the mounting shell, and the second sliding rail and the rack are arranged along the length direction of the sanding machine; the second sliding seat is slidingly arranged on the second sliding rail, the mounting shell is arranged on the second sliding seat, the motor is arranged on the top of the mounting shell, and the gear is arranged on the rotating shaft of the motor and is engaged with the rack.

[0015] The application also provides a 3D printing device comprising the sanding machine.

[0016] The application has the following beneficial effects:

[0017] The sanding machine disclosed by the application can measure the distance between the detection piece and the detection surface through the cooperation of the mounting shell, the horizontal moving mechanism and the lifting mechanism, thereby automatically measuring the uniformity of the sanding gap of the sanding machine after replacing and installing the scraper, without the need for manual detection, so as to avoid the error problem caused by manual detection, save manpower, improve the accuracy of the detection result, ensure the sanding amount and the uniformity of sanding, and improve the forming effect.

[0018] Meanwhile, when not in use, the detection piece is arranged in the mounting shell, and the bottom opening of the mounting shell is covered, so that dust is prevented from entering the mounting shell when the sanding machine is working, thereby ensuring the normal working of the lifting mechanism and the detection piece and the accuracy of detection.

[0019] The application further discloses a 3D printing device, which guarantees the sanding amount of the sand spreader and the uniformity of sand spreading by using the sand spreader, so that the forming effect of the 3D printing device is improved. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the specific embodiments or prior art description will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual proportions.

[0021] Figure 1 A structural schematic view of the sand spreader provided by an embodiment of the present application is shown in the figure.

[0022] Figure 2 A partial view of the sand outlet is shown in the figure.

[0023] Figure 3 A side view of the sand spreader body is shown in the figure.

[0024] Figure 4 A structural schematic view of the bottom of the sand spreader body is shown in the figure.

[0025] Figure 5 A structural schematic view of the inside of the mounting shell is shown in the figure.

[0026] Figure 6 A structural schematic view of the cooperation between the detection member and the bracket is shown in the figure.

[0027] Figure 7 A structural schematic view of the detection member extending out of the opening is shown in the figure.

[0028] Figure 8 A structural schematic view of the detection member extending out of the opening from another perspective is shown in the figure.

[0029] Figure 9 A structural schematic view of the lifting mechanism is shown in the figure.

[0030] Figure 10 A structural schematic view of the cooperation between the cover plate and the locking assembly is shown in the figure.

[0031] Reference signs:

[0032] 10 - sand spreader body, 11 - first base plate, 111 - first reference surface, 12 - scraper plate, 121 - detection surface, 13 - second base plate, 131 - second reference surface, 14 - sand outlet.

[0033] 20 - mounting shell, 21 - opening, 22 - bracket lug, 221 - second gap.

[0034] 30 - horizontal moving mechanism, 31 - second slide rail, 32 - second slide base, 33 - rack, 34 - motor, 35 - gear;

[0035] 40 - detection piece;

[0036] 50 - lifting mechanism, 51 - first slide rail, 52 - first slide base, 53 - connecting rod, 54 - bracket, 55 - electric push rod, 56 - connecting arm;

[0037] 60 - cover plate, 61 - first notch;

[0038] 70 - locking assembly, 71 - mounting support, 72 - shaft, 73 - threaded rod, 74 - locking handle, 741 - fastening part;

[0039] 80 - drag chain. DETAILED DESCRIPTION

[0040] The embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0041] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in the present application should be understood as the usual meanings understood by the skilled in the art to which the present application belongs.

[0042] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0043] In addition, the terms "first", "second", and the like are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0044] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0045] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0046] Example 1

[0047] like Figures 1-10 As shown, in one embodiment of the present invention, a sand spreader is provided, including a sand spreader body 10, a mounting housing 20, a lateral movement mechanism 30, at least one detection element 40, and a lifting mechanism 50.

[0048] A first substrate 11 and a second substrate 13 are fixed to the bottom of the sand-laying device body 10. The gap between the first substrate 11 and the second substrate 13 forms the lower sand inlet 14 of the sand-laying device body 10. A first reference surface 111 is formed on the sidewall of the first substrate 11 facing the second substrate 13, and a second reference surface 131 is formed on the sidewall of the second substrate 13 facing the first substrate 11. The distance between any point on the first reference surface 111 and the second reference surface 131 is the same. A scraper 12 is detachably mounted on the bottom of the second substrate 13. Therefore, the horizontal height of the bottom surface of the scraper 12 is lower than the horizontal height of the bottom surface of the first substrate 11. A detection surface 121 is formed on the sidewall of the scraper 12 facing the first reference surface 111.

[0049] The installation housing 20 is movably installed on the sand spreader body 10, and the bottom of the installation housing 20 is provided with an openable and closable opening 21 (to be further described below), the horizontal height of the opening 21 is higher than the horizontal height of the first base plate 11, and the horizontal moving mechanism 30 is used to drive the installation housing 20 to move along the length direction of the sand spreader body 10. The detection member 40 is vertically (i.e. along the height direction of the sand spreader body 10) lifted and fitted in the installation housing 20, and the detection member 40 is used to detect the distance between it and the detection surface 121. The lifting mechanism 50 is used to drive the detection member 40 to perform lifting action, so as to make the detection member 40 extend out of the opening 21 or retract into the installation housing 20.

[0050] The sand spreader disclosed in the embodiment is a one-way sand spreading structure, and it is required to ensure that the distance between the detection surface 121 of the scraper 12 and the first reference surface 111 at any position is within the error range. Therefore, after the scraper 12 is installed on the second base plate 13, the maintenance personnel first clean the detection surface 121 and open the opening 21 at the bottom of the installation housing 20. Then, the controller (not shown in the figure, which can be a PLC, etc., and will not be described here) starts the horizontal moving mechanism 30, so as to drive the installation housing 20 to move to the detection point a near the end of the sand spreader body 10, and then the lifting mechanism 50 drives one or more detection members 40 to extend out of the opening 21 of the installation housing 20.

[0051] Since the laser emitted by the detection member 40 is perpendicular to the first reference surface 111 and the second reference surface 131, if the distance between the detection member 40 and the second reference surface 131 is recorded as L0 (L0 is measured in advance), and the distance between the detection member 40 and the detection surface 121 is recorded as L1, only when the difference between L0 and L1 is within the allowable error range, it means that the detection point a meets the requirements, i.e. at the detection point a, the gap of the sand outlet 14 between the detection surface 121 and the first reference surface 111 meets the requirements. On the contrary, if the difference between L0 and L1 exceeds the allowable error range, it means that the detection point a does not meet the requirements, and therefore, the maintenance personnel need to adjust the tightness of the bolt a of the scraper 12 corresponding to the detection point a until the difference between L0 and L1 is within the allowable error range.

[0052] Then, the horizontal moving mechanism 30 drives the installation housing 20 to move, so as to move the detection member 40 to the next detection point b, until all the detection points are detected, so that the detection and adjustment of the uniformity of the gap of the sand outlet 14 are realized. After the detection is completed, the lifting driving mechanism drives all the detection members 40 to retract into the installation housing 20, and the maintenance personnel can reseal the opening 21 of the installation housing 20.

[0053] The sanding device disclosed in the embodiment can measure the distance between the detection piece 40 and the detection surface 121 through the integration of one or more detection pieces 40 on the sanding device body 10, the cooperation of the installation housing 20, the transverse movement mechanism 30 and the lifting mechanism 50, and thus can automatically measure the uniformity of the gap of the sand outlet 14 of the sanding device after the replacement and installation of the scraper 12, without the need for manual detection, so as to avoid the error problem caused by manual detection, save manpower, improve the accuracy of the detection result, and ensure the sanding amount and the uniformity of sanding, thereby improving the forming effect.

[0054] Meanwhile, the detection piece 40 is in the installation housing 20 when not in use, and the bottom opening 21 of the installation housing 20 is covered, so that dust does not enter the installation housing 20 when the sanding device is working, thereby ensuring the normal work of the lifting mechanism 50 and the detection piece 40 and the accuracy of detection.

[0055] In an embodiment, the lifting mechanism 50 includes a lifting driving assembly and at least one lifting guide assembly, and the number of the lifting guide assemblies corresponds to the number of the detection pieces 40. The lifting guide assembly includes a first sliding rail 51, a first sliding seat 52, a connecting rod 53 and a bracket 54, the first sliding rail 51 is fixed in the installation housing 20 in the vertical direction, the first sliding seat 52 is slidingly fitted on the first sliding rail 51, the connecting rod 53 is fixed on the first sliding seat 52, the bracket 54 is fixed on the bottom of the connecting rod 53, and the detection piece 40 is fixed on the bracket 54. The lifting driving assembly is used to drive all the first sliding seats 52 to move up and down synchronously.

[0056] When it is necessary to extend the detection piece 40 out of the installation housing 20, the maintenance personnel first open the bottom opening 21 of the installation housing 20, and then the controller starts the lifting driving assembly to drive all the first sliding seats 52 to slide downward along the first sliding rail 51, so that the connecting rod 53 also drives the bracket 54 and the detection piece 40 to move downward synchronously, and when the emission end of the detection piece 40 is aligned with the detection surface 121, the distance between the detection piece 40 and the detection surface 121 at the detection point can be measured.

[0057] The structure design of the cooperation between the first sliding seat 52 and the first sliding rail 51 ensures the smoothness of the movement of the base, the connecting rod 53 and the detection piece 40, and also reduces or even avoids the shaking of the detection piece 40.

[0058] In one embodiment, a plurality of detection pieces 40 are provided, and the plurality of detection pieces 40 are uniformly arranged along the length direction of the sanding machine body 10. The detection piece 40 can adopt a high-precision laser displacement sensor, and the working principle of the laser displacement sensor is a prior art which will not be described herein. By designing the plurality of detection pieces 40 and the arrangement of the plurality of detection pieces 40, the plurality of adjacent detection points can be synchronously detected, and the detection efficiency is improved. At the same time, the number of moving times of the installation shell 20 is also reduced, thereby reducing the shaking of the detection piece 40.

[0059] In one embodiment, the lifting driving assembly includes a plurality of driving units, and each driving unit includes an electric push rod 55 and a connecting arm 56. The electric push rod 55 is fixed between two adjacent first sliding rails 51 in the vertical direction, and the telescopic rod of the electric push rod 55 is arranged downward. The connecting arm 56 is connected with the telescopic rod of the electric push rod 55, and the two ends of the connecting arm 56 are respectively connected with two adjacent first sliding seats 52.

[0060] When the electric push rod 55 extends the telescopic rod, the electric push rod 55 can synchronously drive the two adjacent first sliding seats 52 under the driving of the connecting arm 56. At the same time, the plurality of driving units synchronously act, thereby ensuring the stability of the first sliding seat 52, the connecting rod 53 and the detection piece 40 during the movement, and ensuring the detection accuracy.

[0061] In one embodiment, the sanding machine further includes a cover plate 60 and a locking assembly. The cover plate 60 can cover the opening 21, and the locking assembly is used to lock the cover plate 60 on the installation shell 20 or separate the cover plate 60 from the installation shell 20. The two sides of the cover plate 60 are respectively provided with a first notch 61, and the locking assembly includes two locking units which are respectively arranged on the two sides of the installation shell 20.

[0062] The locking unit includes a mounting support 71, a shaft 72, a threaded rod 73 and a locking hand wheel 74. The mounting support 71 is fixed on the side wall of the installation shell 20, the shaft 72 is rotatably fitted in the mounting support 71, the threaded rod 73 is fixed on the shaft 72, and the threaded rod 73 can be rotated into the first notch 61. The locking hand wheel 74 is threadedly fitted on the threaded rod 73, and the locking hand wheel 74 is provided with a fastening portion 741. When the threaded rod 73 is rotated into the first notch 61, the fastening portion 741 can abut against the bottom surface of the cover plate 60.

[0063] After the cover plate 60 covers the opening 21, the maintenance personnel rotates the threaded rod 73 to make it rotate into the first notch 61, and then rotates the locking hand wheel 74. When the fastening portion 741 abuts against the bottom surface of the cover plate 60 and the locking hand wheel 74 cannot be rotated any more, it means that the locking is in place. At this time, the cover plate 60 is tightly abutted against the opening 21 of the installation shell 20, so that the locking effect of the cover plate 60 is ensured, and the dust is prevented from entering the installation shell 20.

[0064] In one embodiment, two side walls of the installation housing 20 are respectively provided with a lug 22, the bottom surface of the lug 22 is flush with the bottom surface of the installation housing 20, the lug 22 is provided with a second gap 221 for the threaded rod 73 to rotate into, and when the threaded rod 73 rotates into the second gap 221, the fastening part 741 can abut against the bottom surface of the lug 22.

[0065] After detecting the uniformity of the gap of the sand outlet 14, the cover plate 60 needs to be removed first. In order to avoid the shaking of the threaded rod 73 and the locking handle 74 from causing the shaking of the detection piece 40 during the movement of the installation housing 20, two lugs 22 are designed. After the cover plate 60 is removed, the maintenance personnel rotates the threaded rod 73 to make it rotate into the second gap 221, and then rotates the locking handle 74. When the fastening part 741 abuts against the bottom surface of the lug 22 and the locking handle 74 cannot be rotated any more, it means that the locking is in place. At this time, the threaded rod 73 and the locking handle 74 will not shake.

[0066] In one embodiment, the horizontal moving mechanism 30 includes a second sliding rail 31, a second sliding seat 32, a rack 33, a motor 34 and a gear 35. The second sliding rail 31 and the rack 33 are arranged on the side of the sand spreader body 10 facing the installation housing 20, and are arranged along the length direction of the sand spreader body 10. The second sliding seat 32 is slidingly fitted on the second sliding rail 31, the installation housing 20 is arranged on the second sliding seat 32, the motor 34 is arranged on the top of the installation housing 20, and the gear 35 is arranged on the rotating shaft of the motor 34 and is engaged with the rack 33.

[0067] The second sliding seat 32 and the second sliding rail 31 adopt a roller guide rail structure. When the motor 34 drives the gear 35 to rotate, the horizontal movement of the installation housing 20 can be realized through the cooperation of the gear 35 and the rack 33, and the cooperation of the second sliding seat 32 and the second sliding rail 31. Of course, since the installation housing 20 will move during detection, a drag chain 80 is arranged on the side wall of the sand spreader body 10 to constrain and protect the wire harnesses of the detection piece 40, the electric push rod 55, the motor 34 and the like.

[0068] Embodiment two

[0069] In another embodiment of the present application, a 3D printing device is provided, which includes the sand spreader in the above-mentioned embodiment one. By using the above-mentioned sand spreader, the sand spreading amount and the uniformity of sand spreading of the sand spreader are ensured, so that the forming effect of the 3D printing device is improved.

[0070] In the specification of the present application, a large number of specific details are described. However, it can be understood that the embodiments of the present application can be practiced without these specific details. In some examples, well-known methods, structures and techniques are not shown in detail in order not to obscure the understanding of the present specification.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the description of the present application.

Claims

1. A sand spreader characterized in that, The sanding machine comprises: a sanding machine body, a first base plate and a scraper are arranged at the bottom of the sanding machine body, the height of the bottom surface of the scraper is lower than that of the first base plate, a first reference surface is formed on the side wall of the first base plate facing the scraper, and a detection surface is formed on the side wall of the scraper facing the first reference surface; a mounting shell is arranged on the sanding machine body, an openable and closable opening is arranged at the bottom of the mounting shell, and the height of the opening is higher than that of the first base plate; a horizontal moving mechanism is arranged to drive the mounting shell to move along the length direction of the sanding machine body; at least one detection member is vertically arranged in the mounting shell, and the detection member is arranged to detect the distance between the detection member and the detection surface; and a lifting mechanism is arranged to drive the detection member to perform lifting action, so that the detection member extends out of the opening or retracts into the mounting shell. The lifting mechanism comprises a lifting driving assembly and at least one lifting guide assembly, and the number of the lifting guide assemblies corresponds to the number of the detection members; 2. The sand spreader of claim 1, wherein, the lifting guide assembly comprises a first sliding rail, a first sliding seat, a connecting rod and a bracket, the first sliding rail is vertically arranged in the mounting shell, the first sliding seat is slidingly arranged on the first sliding rail, the connecting rod is arranged on the first sliding seat, the bracket is arranged at the bottom of the connecting rod, and the detection member is arranged on the bracket; the lifting driving assembly is arranged to drive all the first sliding seats to perform synchronous lifting action. A plurality of detection members are arranged, and the detection members are arranged at intervals along the length direction of the sanding machine body.

3. A sand spreader according to claim 2, characterised in that, The lifting driving assembly comprises a plurality of driving units, each driving unit comprises an electric push rod and a connecting arm, the electric push rod is vertically arranged between two adjacent first sliding rails, and the telescopic rod of the electric push rod is arranged downward; 4. A sand spreader according to claim 3, characterised in that, the connecting arm is connected with the telescopic rod of the electric push rod, and the two ends of the connecting arm are respectively connected with two adjacent first sliding seats. A cover plate and a locking assembly are further arranged, the cover plate can cover the opening, the locking assembly is arranged to lock the cover plate on the mounting shell or separate the cover plate from the mounting shell; 5. The sand spreader of claim 1, wherein, first notches are arranged on the two sides of the cover plate, the locking assembly comprises two locking units, the two locking units are arranged on the two sides of the mounting shell respectively, and each locking unit comprises: a mounting support arranged on the side wall of the mounting shell; a pivot shaft rotatably arranged in the mounting support; a threaded rod arranged on the pivot shaft, the threaded rod can be rotated into the first notch; and a locking hand wheel threadedly arranged on the threaded rod, a fastening part is arranged on the locking hand wheel, and when the threaded rod is rotated into the first notch, the fastening part can abut against the bottom surface of the cover plate. second notches are arranged on the bottom surfaces of the lugs, the bottom surfaces of the lugs are flush with the bottom surface of the mounting shell, the threaded rod can be rotated into the second notches, and when the threaded rod is rotated into the second notches, the fastening part can abut against the bottom surface of the lug.

6. A sand spreader according to claim 5, characterised in that, ​ 7. The sand spreader of claim 1, wherein, The transverse moving mechanism comprises a second sliding rail, a second sliding base, a rack, a motor and a gear, the second sliding rail and the rack are arranged on the side of the sand spreader body facing the mounting shell, and the second sliding rail and the rack are arranged along the length direction of the sand spreader; The second sliding base is slidingly fitted on the second sliding rail, the mounting shell is arranged on the second sliding base, the motor is arranged on the top of the mounting shell, and the gear is arranged on the rotating shaft of the motor and engaged with the rack.

8. A 3D printing device, characterized by The sand spreader comprises the sand spreader according to any one of claims 1-7.

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