Binder spraying and rapid forming equipment

Abstract

The utility model discloses a binder spraying and rapid forming device, and relates to the technical field of binder spraying and forming. The device comprises a forming cylinder, a printing nozzle assembly, a powder spreading roller, a heating assembly and a temperature controller, the printing nozzle assembly comprises a nozzle mounting seat and a nozzle; the heating assembly comprises a top heater, a side heater and a bottom heater; the top heater is mounted at the bottom of one side, far away from the powder spreading roller, of the nozzle mounting seat corresponding to the nozzle; the multiple sets of side heaters are sequentially installed in the side wall of the forming cylinder in the height direction of the forming cylinder. The bottom heater is mounted in the bottom wall of the forming cylinder; and the temperature controller is electrically connected with the top heater, the side heater and the bottom heater. The powder bed in the initial laying stage can be preheated through the bottom heater, green body forming is accelerated, the workpiece pushing phenomenon is avoided, the forming strength of the green body is continuously improved through the synergistic effect of all the heaters, and deformation of the green body due to gravity, permeation and diffusion is avoided.

Description

TECHNICAL FIELD

[0001] The utility model relates to binder jetting technical field, more specifically relates to a kind of binder jetting rapid prototyping equipment. BACKGROUND

[0002] In recent years, binder jetting metal material 3D printing as an advanced additive manufacturing technology, with its forming rate fast, material utilization rate is high, production cost is low and production process does not need extra support and other advantages become the focus of industrial application, the basic process of this process is: through the jetting binder metal powder material layer by layer bonding, realize complex parts green forming, then through drying solidification, powder cleaning obtains complete green without residual powder, finally through debinding sintering forms the product parts with required mechanical properties.But, in actual production application process, binder jetting forming technology still has many technical bottlenecks, the "push piece" defect in powder bed laying process and the deformation defect of the green formed in printing process in powder bed are two big problems.

[0003] First, the "push piece" defect in powder bed laying process, especially the first 10-20 layers are most prone to occur, the generation of this defect is mainly because powder bed laying process, whether it is powder roller, scraper or other powder laying device structure, the powder pre-laid in powder laying process can be decomposed into horizontal component force and vertical component force, i.e. vertical component force provides compaction to the formed powder bed, and the generated horizontal component force will generate lateral thrust to the formed powder bed, when the shear resistance of the two-dimensional sectional pattern formed by "last layer" powder bed through binder jetting is less than the horizontal component force of the pre-laid powder to the formed powder bed, "push piece" defect will occur.The existing technology reduces the horizontal component force in powder laying process by optimizing powder laying device structure and continuously iterating binder system to obtain high-strength binder as the main solution approach. So far, single / double powder roller reverse powder laying method is the mainstream powder laying method, but when using environmentally friendly, economical and low-carbon residual water-based binder, obvious "push piece" phenomenon still occurs.

[0004] In addition, the deformation defect of the green formed in powder bed is generally found in the printing process of high-height and thin-wall structure product parts, as the printing time is longer, under the action of gravity, infiltration diffusion, etc., the green body produces deformation, affects product consistency and qualification rate. Therefore, how to provide a kind of rapid prototyping binder jetting printing device capable of avoiding "push piece" defect and preventing green from deforming in powder bed is a problem to be solved by those skilled in the art. UTILITY MODEL CONTENTS

[0005] In view of this, the present invention aims to provide a binder spraying rapid prototyping equipment to improve the shear strength of the green blank, avoid the phenomenon of pushing parts, and improve the defect of the green blank being easily deformed in the powder bed.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A rapid prototyping device for adhesive spraying, comprising:

[0008] A forming cylinder, wherein the top of the forming cylinder is open;

[0009] A printhead assembly, comprising a printhead mount and a printhead, the printhead mount being connected to a sliding mechanism of the printer to move over an opening at the top of the forming cylinder, the printhead being mounted at the bottom of the printhead mount;

[0010] A powder spreading roller is arranged side-by-side with the nozzle and rotatably mounted on the bottom of the nozzle mounting base;

[0011] The heating assembly includes a top heater, a side heater, and a bottom heater. The top heater is installed at the bottom of the nozzle mounting base on the side of the nozzle away from the powder spreading roller. Multiple sets of side heaters are provided and are sequentially installed inside the side wall of the forming cylinder along the height direction of the forming cylinder. The bottom heater is installed inside the bottom wall of the forming cylinder.

[0012] A thermostat, which is electrically connected to the top heater, the side heater and the bottom heater.

[0013] The beneficial effects achievable by this invention are as follows: During the printing process, the nozzle moves synchronously with the powder-spreading roller and the top heater, allowing the binder to be sprayed onto the powder layer through the nozzle and preliminarily dried under the heating of the top heater, thus forming a pre-formed green blank. The bottom heater can preheat the powder bed in the initial stage of powder spreading, accelerating the formation of the green blank and avoiding the phenomenon of pushing parts. At the same time, under the action of the side heater, the green blank can be further dried, promoting the further removal of solvent in the green blank, continuously improving the forming strength of the green blank, and improving the situation where the green blank is deformed due to gravity, penetration diffusion, etc., which affects the product consistency and pass rate.

[0014] Preferably, a nozzle heat insulation plate is provided between the nozzle and the top heater. This prevents the nozzle temperature from becoming too high, which would affect its service life, and also prevents the adhesive inside the nozzle from becoming too hot, causing the solvent to evaporate prematurely and affecting the bonding quality.

[0015] Preferably, the bottom of the heat insulation plate of the spray head is provided with a top temperature sensor, and the top temperature sensor is electrically connected to the temperature controller. The top temperature sensor is used to monitor the temperature of the top surface of the powder bed in real time, to ensure that the sprayed binder can realize interlayer penetration and diffusion and solvent volatilization in the binder, and to strengthen the strength of the green body.

[0016] Preferably, the forming cylinder comprises a side plate and a movable bottom plate; the side plate is internally provided with an annular first fixed groove, and a plurality of side heaters are sequentially arranged in the first fixed groove along the height direction of the side plate; the movable bottom plate is slidably arranged on the inner side wall of the side plate, and the movable bottom plate is internally provided with a second fixed groove, and the bottom heater is fixed in the second fixed groove. The side heater and the bottom heater are arranged in the inner side wall and the bottom wall of the forming cylinder, heat is conducted to the powder bed through the cylinder wall, the internal temperature of the powder bed is increased, the drying and forming of the green body are accelerated, the temperature in the powder bed is prevented from being reduced, and incomplete removal of the solvent in the binder is prevented, so that the green body is deformed and the forming quality is affected.

[0017] Preferably, a heat preservation layer is fixed on the outer ring side of the side heater in the first fixed groove, to play a heat preservation role and reduce heat loss.

[0018] Preferably, a sealing ring is fixed on the outer ring wall surface of the movable bottom plate. The sealing ring can prevent powder leakage and reduce heat loss through the gap between the movable bottom plate and the side plate.

[0019] Preferably, a plurality of side temperature sensors are further included, a plurality of first installation grooves are uniformly and spaced apart on the inner ring wall surface of the side plate along the height direction of the side plate, a side heat insulation block is arranged in each first installation groove, a first heat insulation groove is arranged in the middle of the inner side wall of each side heat insulation block, and a plurality of side temperature sensors are arranged in the first heat insulation grooves and electrically connected to the temperature controller. The side temperature sensors are used to monitor the temperature between layers in the powder bed in real time.

[0020] Preferably, a bottom temperature sensor is further included, a second installation groove is arranged in the center of the top of the movable bottom plate, a second heat insulation block is fixed in the second installation groove, a second heat insulation groove is arranged in the center of the top of the second heat insulation block, and the bottom temperature sensor is arranged in the second heat insulation groove and electrically connected to the temperature controller. The bottom temperature of the powder bed is monitored to prevent the bottom temperature of the powder bed from being too high or too low.

[0021] Preferably, the top heater is an infrared heater. The infrared heating technology is used to quickly heat the surface of the powder bed, to promote preliminary drying of the binder and preliminary forming of the green body.

[0022] Preferably, the side heater and the bottom heater are both electromagnetic heaters. By using electromagnetic induction heating technology, electromagnetic induction is generated in the movable bottom plate by electric current, that is, countless small eddy currents are generated, so that the movable bottom plate is heated at high speed, thereby transferring heat to the powder bed and making the internal heating of the powder more uniform and efficient.

[0023] Through the above technical scheme, compared with the prior art, the adhesive injection rapid forming equipment provided by the utility model synchronously moves the spray head, the powder spreading roller and the top heater, sprays the adhesive on the powder layer on which the powder is spread through the spray head, and preliminarily dries under the heating of the top heater to form a formed green body, and under the action of the side heater and the bottom heater, the powder bed can be preheated, the forming of the green body is accelerated, the phenomenon of pushing the part is avoided, the green body can be further dried, the solvent in the green body is further removed, the strength of the formed green body is continuously improved, the deformation of the green body caused by the action of gravity, penetration and diffusion and the like is avoided, and the consistency and the qualified rate of the product are improved; the top temperature sensor, the side temperature sensor and the bottom temperature sensor are used to monitor the temperature of each part of the powder bed in the heating process, so that the temperature is prevented from being too high or too low to affect the forming quality, and the uniformity of the green body forming is ensured; each sensor is installed in the corresponding heat insulation groove, so that the contact with the heater is avoided to affect the accuracy of measurement. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or the prior art, the drawings needed to be used in the embodiment or the prior art description will be briefly introduced below, and obviously, the drawings in the following description are only the embodiments of the utility model, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creating labor.

[0025] Figure 1 A structure schematic view of the adhesive injection rapid forming equipment provided by the utility model is provided.

[0026] Figure 2 A structure schematic view of the spray head assembly, the top heater and the powder spreading roller provided by the utility model is provided.

[0027] Figure 3 A structure schematic view of the spray head assembly, the top heater and the powder spreading roller provided by the utility model is provided. Figure 1 A sectional structure schematic view of part A-A in the middle.

[0028] Figure 4 A sectional structure schematic view of part A-A in the middle. Figure 1 An enlarged structure schematic view of part B in the middle.

[0029] In the figure: 10, forming cylinder, 11, side plate, 111, outer side plate, 112, inner side plate, 113, top plate, 12, movable bottom plate, 13, heat preservation layer, 14, sealing ring, 20, printing nozzle assembly, 21, nozzle mounting seat, 22, nozzle, 23, nozzle heat insulation plate, 30, powder laying roller, 40, heating assembly, 41, top heater, 42, side heater, 43, bottom heater, 50, top temperature sensor, 60, side temperature sensor, 61, side heat insulation block, 70, bottom temperature sensor, 71, second heat insulation block. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0031] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0032] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0033] Please refer to Figures 1-4 The embodiment of the present application discloses a kind of binder injection rapid prototyping equipment, comprising: forming cylinder 10, printing nozzle assembly 20, powder laying roller 30, heating assembly 40 and temperature controller;

[0034] The top of the forming cylinder 10 is open to facilitate powder entering. The printing head assembly 20 comprises a printing head mounting seat 21 and a printing head 22. The printing head mounting seat 21 is connected to the sliding mechanism of the printer to move above the top of the forming cylinder 10 to print the required pattern. The printing head 22 is mounted at the bottom of the printing head mounting seat 21. The powder spreading roller 30 is arranged side by side with the printing head 22 and is rotatably mounted at the bottom of the printing head mounting seat 21 to spread the powder evenly.

[0035] The heating assembly 40 comprises a top heater 41, side heaters 42 and a bottom heater 43. The top heater 41 is mounted at the bottom of the printing head mounting seat 21 corresponding to the side of the printing head 22 away from the powder spreading roller 30 to preliminarily dry the sprayed binder to form.

[0036] The temperature controller is electrically connected to the top heater 41, the side heaters 42 and the bottom heater 43 to control and adjust the heating temperature of each heater.

[0037] In a specific embodiment, a printing head heat insulation plate 23 is arranged between the printing head 22 and the top heater 41 to prevent the temperature of the printing head 22 from being too high to affect its service life and prevent the temperature of the binder in the printing head 22 from being too high to cause the solvent to volatilize too early and affect the binding property.

[0038] In a specific embodiment, a top temperature sensor 50 is mounted at the bottom of the printing head heat insulation plate 23, and the top temperature sensor 50 is electrically connected to the temperature controller. The top temperature sensor 50 is used to monitor and adjust the temperature of the top surface of the powder bed in real time to ensure that the sprayed binder can realize interlayer penetration and diffusion and solvent volatilization in the binder to strengthen the forming strength of the green body. In a specific embodiment, a third heat insulation groove is arranged at the bottom of the printing head heat insulation plate 23, and the top temperature sensor 50 is embedded in the third heat insulation groove. The top of the top heater 41, the printing head 22, the top temperature sensor 50 and the bottom of the printing head 22 are all higher than the bottom of the powder spreading roller 30 to avoid affecting the flatness of the powder layer by contacting the spread powder layer.

[0039] In an embodiment, the forming cylinder 10 comprises a side plate 11 and a movable bottom plate 12; the side plate 11 is internally provided with an annular first fixed groove, and a plurality of side heaters 42 are sequentially installed in the first fixed groove along the height direction of the side plate 11; the movable bottom plate 12 is slidingly installed on the inner side wall of the side plate 11, and the movable bottom plate 12 is internally provided with a second fixed groove, and a bottom heater 43 is fixed in the second fixed groove. The side heaters 42 and the bottom heater 43 are installed inside the side wall and the bottom wall of the forming cylinder 10, and heat is conducted to the powder bed through the cylinder wall, so as to improve the internal temperature of the powder bed, prevent the temperature in the powder bed from being reduced, and prevent incomplete removal of the solvent in the binder, which causes the green body to deform and affects the forming quality.

[0040] In an embodiment, a heat preservation layer 13 is fixed on the outer ring side of the side heater 42 in the first fixed groove, and the heat preservation layer 13 is made of heat preservation and insulation materials, so as to play a heat preservation and insulation role and reduce heat loss.

[0041] In an embodiment, a sealing ring 14 is fixed on the outer ring wall surface of the movable bottom plate 12, and the movable bottom plate 12 is sealingly and slidingly connected with the side plate 11, so as to prevent powder leakage and reduce heat loss in the forming cylinder 10.

[0042] In an embodiment, referring to Figure 1 and Figure 4 , the side heater 42 and the bottom heater 43 can be detachably installed in the side plate or the movable bottom plate. The side plate 11 comprises an outer side plate 111 and an inner side plate 112 which are arranged at intervals, and a top plate 113 which is installed on the top of the inner side plate 112 and the outer side plate 111, and the first fixed groove is formed at the gap between the inner side plate 112 and the outer side plate 111, and the outer side plate 111, the heat preservation layer 13, the side heater 42 and the inner side plate 112 are sequentially connected by bolts, so as to facilitate disassembly, maintenance or replacement of each structure.

[0043] In an embodiment, the movable bottom plate 12 comprises an upper bottom plate and a lower bottom plate which are arranged at intervals, and the bottom heater 43 is installed in the gap between the upper bottom plate and the lower bottom plate, and a heat preservation layer can also be installed in the movable bottom plate 12, which is arranged between the lower bottom plate and the bottom heater 43, and the upper bottom plate, the bottom heater 43, the heat preservation layer and the lower bottom plate are sequentially connected by bolts.

[0044] As Figure 1 , Figure 3In an embodiment, a plurality of side temperature sensors 60 are further included, a plurality of first installation grooves are uniformly and spaced apart along the height direction of the inner annular wall surface of the side plate 11, and a side heat insulation block 61 is installed in each first installation groove. A first heat insulation groove is formed in the middle of the inner side wall of each side heat insulation block 61, and the plurality of side temperature sensors 60 are installed in the plurality of first heat insulation grooves in correspondence and electrically connected to the temperature controller. The side temperature sensors 60 are used to monitor the temperature of each part inside the powder bed in real time, and the temperature of the side heater 42 is adjusted to ensure that the temperature inside the powder bed is appropriate and consistent, preventing the drying degree of each part of the green body from being inconsistent and affecting the forming of the green body.

[0045] As Figure 1 In an embodiment, a bottom temperature sensor 70 is further included, a second installation groove is formed in the top center of the movable bottom plate 12, a second heat insulation block 71 is fixed in the second installation groove, a second heat insulation groove is formed in the top center of the second heat insulation block 71, and the bottom temperature sensor 70 is installed in the second heat insulation groove and electrically connected to the temperature controller. The temperature of the bottom of the powder bed is monitored to prevent the temperature inside the powder bed from being too high or too low to affect the forming quality. The materials of the nozzle heat insulation plate 23, the side heat insulation block 61, and the bottom heat insulation block 71 are all high-temperature insulation materials, such as ceramic fiber, aluminum silicate fiber, or calcium silicate.

[0046] In an embodiment, the top heater 41 is an infrared heater used to heat the surface of the powder bed to promote the rapid drying of the sprayed binder.

[0047] In an embodiment, the side heater 42 and the bottom heater 43 are both electromagnetic heaters, which include a mounting plate and an electromagnetic coil inside. The two ends of the electromagnetic coil are respectively connected to a power supply and a temperature controller.

[0048] When the device is used, the powder is uniformly laid in the forming cylinder 10 by the powder laying roller 30 to form a powder bed, in the process, the spray head 22 sprays the binder according to the two-dimensional data provided by the computer to form a specific required pattern, and the top heater 41 is used to heat and preliminarily dry the pattern formed by spraying (the drying temperature of the water-based binder is 60-80 DEG C); the top temperature sensor 50 detects the entire powder bed surface during the entire process and feeds back the data in real time, and the temperature controller adjusts the infrared heater in real time according to the feedback to ensure that the temperature error of the powder bed surface is less than or equal to ± 3 DEG C, which can ensure that the sprayed binder can realize interlayer penetration and diffusion and solvent volatilization. During the entire process, the bottom electromagnetic heater generates heat through electromagnetic induction, the bottom temperature sensor 70 detects and feeds back the temperature data in real time, and the temperature controller adjusts the current of the bottom electromagnetic heater in real time according to the feedback to ensure that the temperature error of the powder is less than or equal to ± 3 DEG C, which can preheat the powder bed in the forming cylinder 10 before printing and accurately control the heating temperature, enhance the shear strength of the first 10-20 layers, and avoid the generation of the "pushing piece" defect. At the same time, when printing high product parts, the side electromagnetic heater further heats the powder bed, and the current of the side electromagnetic heater is adjusted in real time by the side temperature sensor 60 to ensure that the temperature error in the powder bed is less than or equal to ± 3 DEG C, which realizes further solvent removal, ensures further solvent removal, continuously improves the strength of the green body, and improves the deformation of the green body caused by gravity, penetration and diffusion, etc., which affects the consistency and yield of the product.

[0049] The embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and the related parts can be referred to the method part.

[0050] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A binder jetting rapid prototyping apparatus, characterized by, The utility model provides a kind of 3D printing device, including: Molding cylinder (10), the molding cylinder (10) top is open; Print head assembly (20), the print head assembly (20) includes print head mounting seat (21) and print head (22), the print head mounting seat (21) is connected the sliding mechanism of printer to move above the molding cylinder (10) top is open, the print head (22) is installed in the bottom of the print head mounting seat (21); Powder roller (30), the powder roller (30) is arranged with the print head (22) and is rotationally installed in the bottom of the print head mounting seat (21); Heating assembly (40), the heating assembly (40) includes top heater (41), side heater (42) and bottom heater (43), the top heater (41) is installed in the bottom of the print head mounting seat (21) corresponding the print head (22) is away from the side of the powder roller (30);The side heater (42) is equipped with multiple groups, and multiple groups of the side heater (42) are sequentially installed in the inside of the side wall of the molding cylinder (10) along the height direction of the molding cylinder (10);The bottom heater (43) is installed in the inside of the bottom wall of the molding cylinder (10); Temperature controller, the temperature controller is electrically connected the top heater (41), the side heater (42) and the bottom heater (43).

2. The binder jetting rapid prototyping apparatus of claim 1, wherein, The print head (22) and the top heater (41) are provided with print head heat insulation plate (23).

3. The binder jetting rapid prototyping apparatus of claim 2, wherein, The bottom of the print head heat insulation plate (23) is installed top temperature sensor (50), and the top temperature sensor (50) is electrically connected the temperature controller.

4. The binder jetting rapid prototyping apparatus of claim 1 wherein, The molding cylinder (10) includes side plate (11) and movable bottom plate (12);The inside of the side plate (11) is provided with annular first fixed slot, and multiple groups of the side heater (42) are sequentially installed in the first fixed slot along the height direction of the side plate (11);The movable bottom plate (12) is slidably installed in the inner side wall of the side plate (11), and the inside of the movable bottom plate (12) is provided with second fixed slot, and the bottom heater (43) is fixed in the second fixed slot.

5. The binder jetting rapid prototyping apparatus of claim 4, wherein, The outside ring side of the first fixed slot corresponding the side heater (42) is fixed with heat preservation layer (13).

6. The binder jetting rapid prototyping apparatus of claim 4, wherein, The outer ring wall surface of the movable bottom plate (12) is fixed with sealing ring (14).

7. The binder jetting rapid prototyping apparatus of claim 4, wherein, It also includes multiple side temperature sensors (60), the inner ring wall surface of the side plate (11) is uniformly spaced apart along its height direction and is provided with multiple first installation grooves, each first installation groove is installed with side heat insulation block (61), and the middle part of the inner side wall of each side heat insulation block (61) is provided with first heat insulation groove, and multiple side temperature sensors (60) are correspondingly installed in multiple first heat insulation grooves and are electrically connected with the temperature controller.

8. The binder jetting rapid prototyping apparatus of claim 7, wherein, It also includes bottom temperature sensor (70), the top center of the movable bottom plate (12) is provided with second installation groove, and the second installation groove is fixed with second heat insulation block (71), and the top center of the second heat insulation block (71) is provided with second heat insulation groove, and the bottom temperature sensor (70) is installed in the second heat insulation groove and is electrically connected with the temperature controller.

9. A binder jetting rapid prototyping apparatus according to any one of claims 1 to 8, wherein, The top heater (41) is an infrared heater.

10. The binder jetting rapid prototyping apparatus of claim 9, wherein, The side heater (42) and the bottom heater (43) are both electromagnetic heaters.

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