Metal additive and subtractive manufacturing device and method

Abstract

The invention belongs to the technical field of metal additive and subtractive manufacturing, and particularly discloses a metal additive and subtractive manufacturing device and method.The device comprises a printing chamber, a laser system, a powder laying and spraying device, a forming cylinder and a subtractive machining mechanism. The powder laying and spraying device can lay metal powder on the forming cylinder and spray a binding agent, the binding agent is used for fixing the powder, powder splashing is reduced, and meanwhile a supporting structure is formed in a non-machining area. The subtractive machining mechanism can stretch into the forming cylinder through the machining channel in the side wall of the forming cylinder, and synchronous subtractive machining is conducted on parts in the additive manufacturing process. The method comprises the steps of laying a metal powder layer, spraying a binder in a partitioned mode, melting and fixing powder through laser, conducting synchronous subtractive machining and the like. By means of binder spraying and synchronous material reduction machining, the beneficial effects that powder splashing is reduced, the part forming quality is improved, machining instability is reduced, and the number of post-treatment procedures is reduced are achieved, and high practicability and economical efficiency are achieved.

Description

Technical Field

[0001] This invention relates to the field of metal additive and subtractive manufacturing technology, and in particular to a metal additive and subtractive manufacturing apparatus and method. Background Technology

[0002] Powder bed fusion (PBF) is an additive manufacturing process that uses a high-energy beam (laser / electron beam) to melt metal powder layer by layer to create three-dimensional parts. This technology can produce parts with complex shapes, uniform grain size, high density, and superior mechanical properties, and has been widely used in the manufacture of high-precision complex parts in aerospace, energy and other fields.

[0003] However, many problems still exist in PBF processing. Among them, "splattering" is a major issue. Spattering refers to particles ejected from the molten pool created by the interaction of a laser or electron beam with the powder bed during the printing process. This spattering phenomenon can adversely affect the forming process, such as affecting the spreading and melting of the next layer of powder, leading to internal defects in the part, or even preventing the part from being formed. Spattering is generally divided into two categories: droplet spattering generated from the "liquid base" of the molten pool and powder spattering generated from the "solid base" of the powder bed. The generation of droplet spattering can be suppressed by optimizing laser energy density, laser beam mode, changing the viscosity of the liquid metal, and printing chamber air pressure, but powder spattering caused by the entrainment effect has a greater impact on the part forming quality, and there is currently no mainstream suppression method.

[0004] With the increasing demand for manufacturing large-size precision parts, multi-laser powder bed fusion technology has attracted attention. However, in multi-laser manufacturing environments, the resulting spatter mainly includes powder spatter caused by the entrainment effect induced by metal vapor and droplet spatter caused by the back pressure of the molten pool, with powder spatter accounting for a larger proportion. The growth rate of powder spatter is an order of magnitude higher than that of droplet spatter, and the spatter generation also increases significantly with the increase of the number of processing laser beams, seriously affecting the processing and forming quality of parts. Currently, there has been much research on the suppression of droplet spatter in single-laser additive manufacturing, but research on spatter countermeasures in the field of multi-laser additive manufacturing is still relatively limited.

[0005] Furthermore, in metal additive manufacturing, a large amount of powder is often required to supply raw materials for powder spreading in the forming cylinder, resulting in low metal powder utilization. As the number of powder cycles increases, the oxide content and powder particle size also increase, negatively impacting the quality of the formed parts. Currently, measures to improve powder utilization and reduce the number of powder cycles are limited. For some parts that occupy a large forming cylinder space but have low actual quality, a large amount of metal powder must be used for powder spreading, which is detrimental to the powder's lifespan. Additively manufactured parts typically require post-processing steps such as support removal and surface finishing. These steps not only increase production time and costs but may also affect the final precision and performance of the parts.

[0006] Therefore, it is necessary to propose a new metal additive and subtractive manufacturing apparatus and method to reduce resource waste and improve production efficiency. Summary of the Invention

[0007] The purpose of this invention is to provide a metal additive and subtractive manufacturing apparatus and method, which achieves advantages such as reducing powder splashing, improving part forming quality, reducing processing instability, reducing the actual amount of powder used in printing, and reducing the time and cost of post-processing steps.

[0008] To achieve the above objectives, the present invention provides the following solution:

[0009] A metal additive and subtractive manufacturing apparatus includes: a printing chamber with a first guide rail extending along the Y-axis; a laser system installed on the top of the printing chamber to provide energy for powder melting; a powder spreading and spraying device slidably connected to the first guide rail; the powder spreading and spraying device includes a powder spreading device and a binder spraying device movable along the X-axis; a forming cylinder located at the bottom of the printing chamber and connected to a Z-axis lifting system, with at least one processing channel opened on its side wall; and a subtractive processing mechanism extending into the forming cylinder through the processing channel to perform subtractive processing on the part during the additive manufacturing process.

[0010] Furthermore, the subtractive processing mechanism includes a first subtractive processing mechanism and a second subtractive processing mechanism, wherein the first subtractive processing mechanism and the second subtractive processing mechanism extend into the processing channels on the front and rear sides of the forming cylinder, respectively.

[0011] Furthermore, the first subtractive processing mechanism and / or the second subtractive processing mechanism are laser processing heads or machining tools.

[0012] Furthermore, the powder spreading device includes an ultrasonic generator and a metal powder nozzle for directional spraying and vibration dispersion of metal powder into the part forming area.

[0013] Furthermore, the metal additive and subtractive manufacturing apparatus also includes a powder cylinder for storing metal powder and conveying the metal powder to the forming cylinder.

[0014] Furthermore, the metal additive manufacturing apparatus also includes a powder-removing cylinder for recovering excess powder.

[0015] A method for manufacturing metal additive-subtractive materials, using the metal additive-subtractive material manufacturing apparatus described in any one of the above claims, the method comprising the following steps:

[0016] A layer of metal powder is laid in the forming cylinder;

[0017] During the operation of the powder spreading device, the binder is sprayed in sections by the binder spraying device: a small amount of binder is sprayed in the part forming area to fix the powder; a solidified layer is formed in the non-processing area, which is thicker than the powder layer.

[0018] The powder, after being melted and fixed by the laser system, is used to form parts layer by layer.

[0019] The subtractive processing mechanism performs subtractive processing on the already formed areas of the part simultaneously.

[0020] Furthermore, the process of applying adhesive in sections using an adhesive spraying device includes:

[0021] A powder fixing area is formed 1-3 mm from the outer edge of the part forming area, and adhesive is sprayed to expand the powder drop area.

[0022] An adhesive-filled area is formed in the non-processing area, and the sprayed adhesive is heated and cured to form a supporting structure.

[0023] Furthermore, the height of the solidified layer in the filling area is 0.03 mm higher than that of the metal powder layer, which is used to isolate the powder in the non-processing area.

[0024] Furthermore, the metal additive and subtractive manufacturing method further includes:

[0025] The molded part is immersed in an organic solvent to dissolve the adhesive support structure;

[0026] The dissolved metal powder is filtered, dried, and reused.

[0027] Furthermore, simultaneous subtractive processing includes: when the part descends with the forming cylinder to the processing channel position, the lateral holes or surfaces of the part are laser- or mechanically processed by the subtractive processing mechanism.

[0028] Furthermore, the use of ultrasonic powder spreading includes:

[0029] The ultrasonic powder spreading path is designed based on the part model, and metal powder is sprayed only directionally into the part forming area.

[0030] Metal-free support parts are formed in the negative angle region of the part using an adhesive.

[0031] As can be seen from the above structure and method, the present invention discloses at least the following beneficial effects:

[0032] This invention integrates a binder spraying and subtractive processing device, which achieves powder splash suppression, improved metal powder utilization, and in-situ subtractive processing in a multi-laser environment, significantly improving the quality of part forming and reducing post-processing steps. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a front view of the metal additive and subtractive manufacturing apparatus of the present invention;

[0035] Figure 2 This is a top view of the metal additive and subtractive manufacturing apparatus of the present invention;

[0036] Figure 3 This is an isometric view of the metal additive and subtractive manufacturing apparatus of the present invention;

[0037] Figure 4 This is a structural diagram of the printing chamber in the metal additive and subtractive manufacturing apparatus of the present invention;

[0038] Figure 5 This is a diagram showing the positional relationship between the powder spreading and spraying device, the subtractive processing mechanism, and the forming cylinder in the apparatus of the present invention;

[0039] Figure 6 This is a schematic diagram of the adhesive spraying area of ​​the present invention;

[0040] Figure 7 This is a schematic diagram of the powder spreading device of the present invention;

[0041] Figure 8 This is a schematic diagram of the adhesive spraying device of the present invention;

[0042] Figure 9 This is a schematic diagram showing the positional relationship between the ultrasonic generator, the metal powder nozzle, and the non-metallic support parts in the powder spreading device of the present invention.

[0043] Figure 10 This is a schematic diagram showing the positional relationship between the spraying device and the metal-free support part of the present invention;

[0044] Figure 11 This is a schematic diagram of the device of the present invention performing subtractive processing on the lateral holes of the powder spreading part of the powder spreading scraper;

[0045] Figure 12 This is a schematic diagram of the subtractive processing of lateral holes in ultrasonically powder-coated parts by the device of the present invention.

[0046] Figure 13 This is a schematic diagram showing the orientation of the first subtractive processing mechanism in the device of the present invention within the coordinate axis.

[0047] In the diagram: 1. Printing chamber; 101. First guide rail; 102. Second guide rail; 2. Laser system; 200. Pulsed laser; 3. Powder spreading and spraying device; 31. Adhesive spraying device; 311. Ultrasonic generator; 312. Metal powder nozzle; 32. Powder spreading device; 4. Processing channel; 5. First subtractive processing mechanism; 6. Second subtractive processing mechanism; 7. Powder leakage cylinder; 8. Forming cylinder; 9. Powder cylinder; 11. Adhesive filling area; 12. Powder fixing area; 13. Part forming area; 14. Powder layer already spread; 15. Metal powder to be spread; 16. Solidified layer in the filling area; 17. Part without metal support. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0050] Reference Figures 1 to 13 As shown, this embodiment provides a metal additive and subtractive manufacturing apparatus, including an apparatus body with a printing chamber 1 on the apparatus body. The printing chamber 1 contains a laser system 2, a powder spreading and spraying device 3, a forming cylinder 8, a powder cylinder 9, and a powder discharging cylinder 7. The forming cylinder 8 contains a subtractive processing mechanism. The laser system 2 includes a continuous pulse laser source and a galvanometer. The laser system 2 provides the energy required for the melting and forming of powder in the apparatus, and the scanning path is controlled by the galvanometer. The powder spreading and spraying device 3 includes a binder spraying device 31 and a powder spreading device 32, providing a uniformly thick powder layer to the forming cylinder 8. Simultaneously, during the return stroke of the powder spreading scraper from the forming cylinder 8 to the powder cylinder 9, the binder spraying device 31 rapidly solidifies the powder layer, preparing for the laser processing stage. At least one side of the forming cylinder 8 has a processing channel 4. The subtractive processing mechanism extends into the forming cylinder 8 through the processing channel 4 on the side wall of the forming cylinder 8, enabling subtractive processing to be performed simultaneously with additive manufacturing.

[0051] Specifically, such as Figures 1 to 5As shown, the forming cylinder 8, powder cylinder 9, and powder dispensing cylinder 7 are all located below the printing chamber 1, while the laser system 2 is installed above the printing chamber 1, directly facing the forming cylinder 8. The pulsed laser 200 emitted by the continuous pulse laser source is directly directed at the forming cylinder 8. A first guide rail 101 is provided on the side wall of the printing chamber 1 along the Y-axis, and the powder spreading and spraying device 3 is slidably connected to this first guide rail 101. In addition, the powder spreading and spraying device 3 also has a guide rail inside, allowing the adhesive spraying device 31 to move linearly along the X-axis. At the same time, a lifting system is connected to the bottom of the forming cylinder 8 to achieve displacement in the Z-axis direction. For example, the forming cylinder 8 can be connected to a servo motor through a precision lead screw guide rail, thereby descending layer by layer in the Z-axis direction. After each layer of powder spreading and laser processing is completed, the forming cylinder 8 will reduce the thickness of the single layer of powder to reserve space for the next layer of powder spreading, and at the same time, it will also drive the formed part to move down synchronously.

[0052] In this embodiment, as Figure 3 As shown, the forming cylinder 8 has processing channels 4 on both the front and rear sides. The subtractive processing mechanism includes a first subtractive processing mechanism 5 and a second subtractive processing mechanism 6, which extend into the two processing channels 4 respectively.

[0053] Further optimization of the scheme: the first subtractive processing mechanism 5 and / or the second subtractive processing mechanism 6 include a laser processing head or a machining tool.

[0054] In this embodiment, the first subtractive processing mechanism 5 and the second subtractive processing mechanism 6 are arranged opposite to each other, and both have three-axis motion capability along the X-axis, Y-axis, and Z-axis directions. Taking the first subtractive processing mechanism 5 as an example, it can move linearly along the Y-axis direction via the second guide rail 102, and its specific structure is as follows. Figure 12 As shown in the figure. It should be noted that although the specific structure driving the first subtractive processing mechanism 5 to move along the X and Z axes is not shown in the figure, those skilled in the art can fully realize this function using various existing technical means. Therefore, the specific three-axis motion mechanism is not limited in detail here. Similarly, the second subtractive processing mechanism 6 can also use a similar three-axis motion mechanism to realize its three-axis motion.

[0055] like Figure 6 As shown, Figure 6A partial area of ​​the forming cylinder 8 is shown, divided into different functional zones. The binder filling zone 11, located in the non-processing area of ​​the forming cylinder 8, is used to spray binder to form a filling layer, serving to isolate the powder and provide support. The powder fixing zone 12, at the edge of the processing area, fixes the powder by spraying a small amount of binder to prevent powder splashing. The part forming zone 13 is the area where the part is actually formed; the amount of binder sprayed is moderate, fixing the powder without affecting the powder melting and forming process. The metal powder to be spread 15 is the metal powder raw material stored in the powder cylinder 9. After being transported to the surface of the forming cylinder 8, it is evenly scraped onto the surface of the forming cylinder 8 as the powder spreading device 32 moves, forming the powder bed required for the current processing layer. The already spread powder layer 14 represents the already laid metal powder layer, on which the binder is sprayed. In certain areas of the forming cylinder 8, the binder filling zone 11 does not perform powder filling to reduce powder usage; instead, it forms a supporting structure through binder solidification. The solidified layer 16, formed in the binder filling zone 11, is a solidified layer slightly higher than the powder layer, used to isolate the powder and support the part.

[0056] like Figure 7 As shown, Figure 7 The process of the powder spreading device 32 spreading powder on the forming cylinder 8 is demonstrated. The powder spreading device 32 includes a powder spreading scraper or other powder spreading tool for spreading a uniform layer of metal powder on the forming cylinder 8. The metal powder is conveyed from the powder cylinder 9 to the forming cylinder 8 and evenly distributed by the powder spreading device 32. The forming cylinder 8 is a container used to hold the metal powder and the formed parts. The powder spreading path is the path along which the powder spreading device 32 moves on the forming cylinder 8, spreading the powder. The thickness of the powder layer is controlled by the powder spreading device 32 to ensure that each layer of powder is uniform.

[0057] like Figure 8 As shown, Figure 8 The process of adhesive spraying device 31 spraying adhesive on molding cylinder 8 is demonstrated. Adhesive spraying device 31 includes a nozzle and a control device for precise adhesive spraying. The nozzle precisely controls the spraying position according to the part design and processing requirements. The amount of adhesive sprayed varies according to the needs of different areas; for example, a small amount of adhesive is sprayed in the powder fixing area 12, and a large amount of adhesive is sprayed in the filling area. Molding cylinder 8 carries metal powder and parts; the adhesive is sprayed onto the powder layer in molding cylinder 8, forming different functional areas. The spraying path is such that adhesive spraying device 31 moves on molding cylinder 8 along a preset path to spray adhesive.

[0058] like Figure 9As shown, in one specific embodiment, the powder spreading device 32 includes an ultrasonic generator 311 and a metal powder nozzle 312. The ultrasonic generator 311 generates ultrasonic vibrations to uniformly distribute the metal powder. The metal powder nozzle 312 sprays the metal powder into a specific area of ​​the forming cylinder 8. In the printing of parts with negative angles or complex structures, the metal-free support part 17 is formed by a support structure cured with adhesive, eliminating the need for additional metal supports. The forming cylinder 8 is a container holding the metal powder and the part, and the part forming area 13 is the area for ultrasonic powder spreading and adhesive spraying, used to form the part.

[0059] like Figure 10 As shown, the adhesive spraying device 31 is used to spray adhesive into the part forming area 13 and non-processing areas. The non-metallic support part 17, formed by the curing of the adhesive, supports the part's forming process. The forming cylinder 8 is a container holding the part and powder. The spraying path is precisely controlled by the adhesive spraying device 31 according to the part design and processing requirements, adjusting the spraying path and spray volume.

[0060] like Figure 11 As shown, Figure 11 This demonstration showcases the subtractive processing of lateral holes in a powder-spreading part using a powder-spreading scraper. A forming cylinder 8 holds the part and powder. The pre-formed part has lateral holes, and the subtractive processing mechanism, including a laser processing head or machining tools, is used to process these holes. The processing channel 4 is a channel in the side wall of the forming cylinder 8, used for the movement of the subtractive processing mechanism. The processing path is a preset path along which the subtractive processing mechanism processes the lateral holes in the part.

[0061] like Figure 12 As shown, Figure 12 This demonstration showcases the subtractive processing of lateral holes in an ultrasonically powder-coated part. A forming cylinder 8 holds the part and powder. The pre-formed part has lateral holes, and the subtractive processing mechanism, including a laser processing head or machining tools, is used to process these holes. The processing channel 4 is a passage in the side wall of the forming cylinder 8, used for the movement of the subtractive processing mechanism. The processing path is a preset path along which the subtractive processing mechanism processes the lateral holes in the part.

[0062] like Figure 13 As shown, Figure 13 The orientation and position of the first subtractive processing mechanism 5 within the coordinate axes are shown. The first subtractive processing mechanism 5 includes a laser processing head or a machining tool, used for subtractive processing of the part. The coordinate axes include the X-axis, Y-axis, and Z-axis, representing the direction and position of movement of the subtractive processing mechanism. The processing direction is the direction of movement of the subtractive processing mechanism along the X-axis, Y-axis, and Z-axis, used for precise control of the processing position and path. The forming cylinder 8 is a container holding the part and powder; the subtractive processing mechanism performs processing operations within the forming cylinder 8.

[0063] In one specific embodiment, the metal additive / subtractive manufacturing apparatus of the present invention, while fulfilling the basic functions of laser powder bed melting (LPBF), innovatively improves the powder spreading blade of existing equipment. Specifically, a binder spraying device 31, along with the motion guide rail and other auxiliary devices required for the binder spraying device 31, are added to the powder spreading blade. These improvements enable the equipment to accurately print the binder design area of ​​the part slices in the forming cylinder 8.

[0064] In traditional powder bed melting processes, after the powder-laying scraper lays a layer of metal powder in the forming cylinder 8, it returns to the powder cylinder to prepare for the laying of the next layer of powder. During the return process, the binder spraying device 31 follows the scraper. When the binder spraying device 31 passes the corresponding area of ​​the powder bed in the forming cylinder 8, its nozzle will open as needed to spray the binder. Figure 8 As shown, in areas requiring laser or electron beam processing, the binder spraying device 31 sprays a small amount of binder to fill only the powder gaps without changing the original powder layer thickness, thus fixing the powder. In non-processing areas, the binder spraying device 31 increases the amount of binder sprayed, forming a thin film filling solidified layer 16 that is one powder layer thickness (e.g., 0.03 mm) higher than the original powder bed height, used to fill the non-processing areas. Figure 7 As shown, when the powder spreading scraper passes through the adhesive filling area 11, it cannot leave powder in that area.

[0065] After the above steps are completed, the laser-processed area in the forming cylinder 8 will be left with fixed powder. This greatly suppresses powder splattering during laser processing. The non-processed areas, however, have no powder residue, thus reducing the amount of powder required for powder spreading. Subsequently, the equipment uses a laser or electron beam to process the powder bed and repeats the powder spreading process until the part is printed.

[0066] The redesigned powder spreading device 32 not only meets the requirements of this invention but also reduces technical risks based on the stability and maturity of existing equipment. By precisely controlling the spraying position and amount of adhesive, it can be ensured that the adhesive is evenly distributed within the designed area of ​​the part, thereby forming a stable support structure. Furthermore, this modification scheme is easy to implement, requires minimal alteration to the original equipment, and thus improves the molding quality of the parts while saving costs and time.

[0067] In one specific embodiment, to further reduce the amount of metal powder used in manufacturing, an ultrasonic powder spreading device 32 can be used to directionally spread powder onto the sliced ​​area of ​​the part. The specific steps are as follows:

[0068] First, based on the part model design file, slicing, path planning, and material allocation design are performed to determine the part slices, the required part forming area 13, the amount of powder used, and the powder spreading path. The adhesive spraying method and area using ultrasonic powder spreading need to be designed according to the structure of the printed part. In addition to fixing the powder in the part forming area 13, the adhesive also needs to act as a powder falling platform. During the printing of parts at negative angles, the adhesive also needs to act as a support for the part.

[0069] After the cabin environment meets the manufacturing requirements, such as Figure 10 As shown, a robotic arm equipped with an ultrasonic spreading device spreads powder across the entire part forming area 13. The metal powder is controlled to fall across the entire part forming area 13, and ultrasonic vibration ensures even distribution. Next, an adhesive spraying device 31 secures the metal powder in the part forming area 13. Simultaneously, adhesive is sprayed 1-3 mm from the outer edge of the part forming area 13 to expand the powder application area for the next layer and to provide adhesive support for subsequent printing as needed. Figure 11 As shown. Subsequently, the powder bed is processed using a laser or electron beam, and the above powder spreading process is repeated until the part is printed.

[0070] By combining the ultrasonic powder spreading device 32 with the binder jetting device 31, a printing effect similar to fused deposition modeling (FDM) can be achieved. By directional powder spreading in the part forming area 13, the amount of recycled powder generated during printing can be significantly reduced, thereby greatly decreasing the number of powder cycles. Simultaneously, there is no need to prepare powder far exceeding the weight of the printed part. Furthermore, using ultrasonic powder spreading eliminates concerns about applying lateral force to long parts during powder spreading with a squeegee, which could cause part deformation.

[0071] In one specific embodiment, to further shorten the manufacturing cycle of the part, a filler layer formed on the powder bed surface by an adhesive can be used as a printing substrate. While additive manufacturing is performed on top of the part, the metal support is removed below by machining, laser, or high-energy beam methods such as plasma, and the surface or holes of the part are processed to obtain a low-roughness surface or a specific surface texture.

[0072] If a powder-spreading squeegee is used, adhesive can be sprayed onto the part forming area 13 and its outer edge 1 mm at the beginning of part printing to fix the powder and improve forming quality. Simultaneously, an adhesive filler layer is laid on the non-forming area of ​​the part, and printing continues until a sufficiently thick and supportive adhesive substrate layer is formed. Subsequently, the formed part descends through the holes around the forming cylinder 8. Through these holes, the laser emitted from the laser processing head can cut or texture the side surface of the part. Furthermore, machining equipment can extend through the holes to process the part surface and the holes, such as... Figure 11 As shown. If the area of ​​the part slice is relatively small compared to the area of ​​the forming cylinder 8, in order to provide higher support for the adhesive substrate layer to support the metal powder above, adhesive or metal supports can be printed around the forming cylinder 8 or in areas that will not be affected by machining.

[0073] In one specific embodiment, an ultrasonic powder spreading device 32 is used for powder spreading, such as... Figure 12 As shown, the powder-feeding platform generated by the curing action of the binder is capable of performing machining, laser, or plasma high-energy beam processing on the already formed parts without interfering with powder spreading and powder melting processing. In this case, once the part descends to a certain height with the forming cylinder 8, high-quality processing can be performed on the surface or holes of the part.

[0074] In this approach, the combination of additive manufacturing and subtractive manufacturing forms a composite additive-subtractive manufacturing process. This method fully utilizes the advantages of binder-assisted additive manufacturing, not only improving the forming quality of parts but also allowing for simultaneous post-processing of the formed portions. By shortening the post-processing time, the increased processing time originally caused by binder spraying is compensated for.

[0075] It should be understood that in practical applications, this device needs to work in conjunction with auxiliary devices such as power supply, controller, drive mechanism, and transmission mechanism. All of the above auxiliary devices can adopt existing technologies. Therefore, in this embodiment, the specific types and models of the above auxiliary devices are not further limited, and the principles of their functions are not elaborated.

[0076] Compared with the prior art, the metal additive and subtractive manufacturing apparatus of this embodiment has at least the following advantages:

[0077] Reduce powder splatter: By adding a binder to the powder bed to help fix the powder bed, the entrainment splatter effect caused by the interaction between the laser and the powder is reduced, the incomplete fusion and metallurgical defects caused by splatter are reduced, and the internal density of the printed parts is improved.

[0078] Powder saving: The adhesive is sprayed into the unprocessed area of ​​the forming cylinder 8 to replace the metal powder that was originally used to fill the forming cylinder 8 but did not participate in the forming of the part. This allows for a variable size of the forming cylinder 8, reduces the amount of metal powder required for a single print, saves powder, reduces the number of powder cycles, and improves powder utilization.

[0079] Improved support stability: The variable forming cylinder 8 can reduce the powder flowability of the powder bed, improve the support stability of the powder on the suspended structure of the part, reduce the design of the support structure, and prevent the powder spreading arm from applying tangential force to the long strip part during powder spreading, which would cause the part to deform.

[0080] Multi-laser processing collaboration: Combining multi-laser additive manufacturing and binder spraying technology, after the powder layer is laid by the powder spreading blade, binder is sprayed according to the 3D part slice data. After the binder reinforces the powder layer, multi-laser processing is performed to suppress powder splashing and improve surface forming quality.

[0081] Simplified support removal: The metal powder reinforced with adhesive can serve as a support structure. The adhesive can then be removed by dissolving it with an organic solvent or by heating and vaporizing it. This eliminates the need for machining specific parts of the support structure, reducing the difficulty and cost of post-processing.

[0082] Additive and subtractive composite processing: The platform after the adhesive has cured can serve as a support for the part and a substrate for the next layer of powder, enabling the simultaneous processing of additive and subtractive manufacturing, further improving the surface quality of the part and reducing post-processing steps.

[0083] This invention also provides a method for manufacturing metal additive and subtractive materials, using the metal additive and subtractive material manufacturing apparatus described in any of the above embodiments. The manufacturing method includes the following steps:

[0084] Step S1: Model file preparation and equipment debugging

[0085] Model file preparation: Prepare the 3D model files for the parts to be manufactured and the adhesive spraying model files. Based on the original 3D model's layered slicing results, enlarge each layer by 0.3mm to 2mm. Simultaneously, based on the model files and computer-aided design (CAD) software, design adhesive support structures at the corresponding overhanging locations to reserve adhesive fixing areas and necessary support structures for subsequent printing. Furthermore, process non-part processing areas by filling them with the adhesive model. After completing the above operations, import the 3D model file for metal processing and the processed adhesive processing model file into the laser additive manufacturing equipment, ready for printing.

[0086] Equipment Debugging: Before printing begins, necessary equipment debugging operations must be performed. These include: deoxygenating the printing chamber 1 and introducing protective gas to ensure a stable atmosphere during printing; filling the toner tank 9 with metal powder to ensure sufficient powder supply; calibrating the toner spreading device 32's scraper to ensure its movement accuracy and toner spreading quality; and preheating the substrate to reach the appropriate printing temperature range. After completing the above debugging operations, the equipment is ready and printing can begin.

[0087] Step S2: Substrate microstructure fabrication, powder spreading and adhesive spraying

[0088] Substrate microstructure fabrication: Before melting the powder with a laser, a certain microstructure texture can be fabricated on the non-part area of ​​the first layer of the substrate using a laser. The high energy output of the laser forms tiny uneven structures on the substrate surface, thereby increasing the contact area between the adhesive and the substrate, improving the adhesion of the adhesive to the substrate, and providing a better foundation for subsequent adhesive spraying and fixation.

[0089] Powder Spreading and Binder Spraying: Subsequently, the powder spreading device 32 moves horizontally from right to left, spreading a uniform layer of metal powder on the corresponding area of ​​the forming cylinder 8. Then, the powder spreading device 32 moves back to the right, and simultaneously, the binder spraying device 31 begins operation. Through the coordinated action of the multi-nozzle spraying of the powder spreading device 32 and the binder spraying device 31, precise processing on the XY plane is achieved. The spraying position and amount of binder are precisely controlled according to a preset pattern. In areas requiring laser processing, only a small amount of binder is sprayed to fix the powder and prevent it from splashing during laser processing; while in non-processing areas, the amount of binder sprayed is increased to form a 0.03mm thick film, filling the non-processing area, thus creating a "variable" forming cylinder 8, providing a stable forming environment for subsequent additive manufacturing processes.

[0090] Step S3, Laser Processing

[0091] Employing multiple lasers as energy output sources, multiple laser beams can simultaneously scan a designated area of ​​the same part, or they can work separately to scan multiple parts. This multi-laser collaborative processing method can significantly improve the processing efficiency of manufacturing large-sized or batch-produced parts. During processing, the pulsed laser 200 acts directly on the mixture of binder and powder. The highly concentrated energy output of the pulsed laser 200 can instantly heat and vaporize the binder, subsequently melting the metal powder to form a molten pool. The binder absorbs some energy during vaporization, thereby reducing the instability caused by the rapid temperature rise of the molten pool and also suppressing spatter in the molten pool. At the same time, in areas not yet processed by the pulsed laser 200, the powder, protected by the binder, is less prone to entrainment-induced powder spatter, reducing the amount of incompletely melted powder inside the part, thus improving processing quality.

[0092] During laser processing, the movement trajectory and energy output of the pulsed laser 200 are controlled according to the preset processing path and parameters. The pulsed laser 200 scans the metal powder layer point by point along the set path, causing the powder to melt and solidify under the energy of the pulsed laser 200, forming a thin layer of the part. Through layer-by-layer stacking, the three-dimensional structure of the part is gradually constructed. Throughout the laser processing, processing parameters such as laser power, scanning speed, and spot size are monitored in real time to ensure the stability of the processing and the reliability of the processing quality.

[0093] Step S4: Repeat powder application and laser processing

[0094] Repeat steps S2 and S3 above for powder application and laser processing until the part is printed to a certain height. Once the part reaches a certain height, a laser processing head or machining tool can be extended through the channel on the side wall of the forming cylinder 8. Utilizing the highly concentrated energy characteristics of the pulsed laser 200, the adhesive cured on the outside of the part is rapidly heated and vaporized. The vaporized adhesive is removed, exposing the surface of the formed area of ​​the part. Subsequently, the surface of the formed area can be processed as needed, such as surface texture processing and dimensional accuracy adjustment.

[0095] Step S5, Subtractive Processing

[0096] The adhesive, whose hardness is much lower than that of the metal parts, is processed using machining methods. Due to the low hardness of the adhesive, there are no machining difficulties, and the surface of the part can be directly machined according to processing requirements, further improving the surface quality. The subtractive machining mechanism controls the machining position in the Z-axis direction through the rising and falling motion of the forming cylinder 8; it achieves machining control in the X-axis direction through movement on the motion guide rail; and it controls the machining depth and accuracy in the Y-axis direction by using a telescopic machining tool or changing the focal length of the pulsed laser 200. This additive-subtractive composite machining method enables simultaneous post-processing of the parts during the additive manufacturing process, improving manufacturing efficiency and quality.

[0097] Step S6: Parts Post-processing and Recycling

[0098] Part Removal and Post-processing: Continue repeating steps S2-S5 until the part is printed. After printing, remove the part along with the substrate from printing chamber 1 for adhesive removal and wire cutting. The substrate and part can be placed in a volatile organic solvent bath, utilizing the solvent's dissolving effect on the adhesive for dissolution and ultrasonic cleaning. High-frequency ultrasonic vibration accelerates the adhesive dissolution process, removing adhesive and adhering powder from the part's surface. After the adhesive is completely dissolved, remove the part. Once the organic solvent has dried and evaporated, it can be sent to a wire cutting machine to separate the part from the substrate using wire cutting.

[0099] Powder Recycling: After removing the binder, excess powder may remain at the bottom of the solution tank or be scattered near the substrate in the heating zone. Simple processing, such as filtration and drying, removes impurities and residual organic solvents, enabling powder recycling and reuse. The recycled powder can be refilled into powder tank 9 for subsequent printing processes, thereby improving material utilization and reducing manufacturing costs.

[0100] The metal additive and subtractive manufacturing method provided in this invention combines additive manufacturing with subtractive manufacturing, fully utilizing the auxiliary role of binders in the additive manufacturing process to achieve efficient and high-quality part manufacturing. This method not only improves the forming quality of parts but also shortens subsequent post-processing time through simultaneous post-processing, effectively improving manufacturing efficiency. Furthermore, this method requires minimal modification to equipment, is easy to implement, and possesses high practicality and economic efficiency.

[0101] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0102] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A metal additive and subtractive manufacturing apparatus, characterized in that, include: The printing chamber (1) is provided with a first guide rail (101) extending along the Y-axis. A laser system (2) is installed on top of the printing chamber (1) to provide energy for powder melting; The powder spreading and spraying device (3) is slidably connected to the first guide rail (101); the powder spreading and spraying device (3) includes a powder spreading device (32) and an adhesive spraying device (31) that move along the X-axis direction; A forming cylinder (8) is located at the bottom of the printing chamber (1) and connected to the Z-axis lifting system. At least one processing channel (4) is opened on the side wall. The subtractive processing mechanism extends into the forming cylinder (8) through the processing channel (4) to perform subtractive processing on the parts during the additive manufacturing process.

2. The metal additive and subtractive manufacturing apparatus according to claim 1, characterized in that, The subtractive processing mechanism includes a first subtractive processing mechanism (5) and a second subtractive processing mechanism (6), which extend from the processing channels (4) on the front and rear sides of the forming cylinder (8), respectively.

3. The metal additive and subtractive manufacturing apparatus according to claim 2, characterized in that, The first subtractive processing mechanism (5) and / or the second subtractive processing mechanism (6) are laser processing heads or machining tools.

4. The metal additive and subtractive manufacturing apparatus according to claim 1, characterized in that, The powder spreading device (32) includes an ultrasonic generator (311) and a metal powder nozzle (312) for directional spraying and vibration dispersion of metal powder to the part forming area (13).

5. The metal additive and subtractive manufacturing apparatus according to claim 1, characterized in that, It also includes a powder cylinder (9) for storing metal powder and conveying the metal powder to the forming cylinder (8).

6. The metal additive and subtractive manufacturing apparatus according to claim 1, characterized in that, It also includes a powder-collecting cylinder (7) for recycling excess powder.

7. A method for manufacturing metal additive-subtractive materials, using the metal additive-subtractive material manufacturing apparatus according to any one of claims 1 to 6, characterized in that, Includes the following steps: A layer of metal powder is laid in the forming cylinder (8); During the operation of the powder spreading device (32), the adhesive is sprayed in sections by the adhesive spraying device (31): a small amount of adhesive is sprayed in the part forming area (13) to fix the powder; a solidified layer (16) is formed in the non-processing area, which is thicker than the powder layer; The laser system (2) melts and fixes the powder, and then forms parts layer by layer; The subtractive processing mechanism performs subtractive processing on the already formed areas of the part simultaneously.

8. The method for manufacturing metal additive and subtractive materials according to claim 7, characterized in that, The adhesive is sprayed in sections using the adhesive spraying device (31), including: A powder fixing area (12) is formed 1-3 mm from the outer edge of the part forming area (13), and the adhesive is sprayed to expand the powder drop area; An adhesive-filled area (11) is formed in the non-processing area, and the sprayed adhesive is heated and cured to form a support structure.

9. The method for manufacturing metal additive and subtractive materials according to claim 7, characterized in that, The height of the solidified layer (16) in the filling area is 0.03 mm higher than that of the metal powder layer, which is used to isolate the powder in the non-processing area.

10. The method for manufacturing metal additive and subtractive materials according to claim 7, characterized in that, Also includes: The molded part is immersed in an organic solvent to dissolve the adhesive support structure; The dissolved metal powder is filtered, dried, and reused.

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