CN112658630B - Additive manufacturing method of metal part - Google Patents

Abstract

The invention relates to a material increase manufacturing method of a metal part, and belongs to the technical field of metal part machining. In order to solve the problems of low longitudinal strength and difficult removal of support in the prior art, the additive manufacturing method of the metal part is provided, and comprises the steps of conveying a metal foil onto a cutting platform through a feeding system, cutting according to a cutting path pre-introduced by the cutting system to obtain a metal foil slice, cutting according to the cutting path to generate a solid part with a shape corresponding to the two-dimensional cross section of each layer of the metal part, and directly taking the non-part solid part of the metal foil slice as a support material to cut layer by layer; transferring each cut metal foil slice to a stacking platform; stacking the next layer of metal foil slices on the surface of the previous layer of metal foil slices sprayed with glue, and repeating the steps until corresponding metal part blanks are formed; after removing the supporting material, embedding the metal part blank into refractory powder, heating and sintering for diffusion welding treatment to obtain a finished product.

Description

Additive manufacturing method of metal part

Technical Field

The invention relates to an additive manufacturing method of a metal part, and belongs to the technical field of metal part machining.

Background

The metal additive manufacturing technology is an emerging technology for directly manufacturing solid parts according to a digital model, and by virtue of the rapid forming and the processing and manufacturing capacity of complex parts, the metal additive manufacturing technology is widely concerned and applied in the fields of aviation, automobiles and energy sources in recent years.

Currently, metal additive manufacturing is mainly divided into direct additive manufacturing and indirect additive manufacturing. The direct additive manufacturing mainly uses high-energy light sources such as laser or electron beams to melt metal powder or wire materials for processing and forming, however, the process involves extremely fast heating and cooling rates, which easily causes defects such as material thermal strain and internal cracks, and meanwhile, the metal materials compatible with laser melting and forming are very limited, and many high-end alloys cannot or are difficult to use such processes. Indirect additive manufacturing processes, which generally use a large amount of binder to bind the metal powder and densify the powder using subsequent debinding sintering, produce a volume shrinkage that is difficult to control, typically up to 20% or more, and sometimes involve very complex nonlinear shrinkage. A large number of trial and error experiments and compensation algorithms are required and applicability is limited. In recent years, with the improvement of metal foil manufacturing technology, the use of foil as a material for additive manufacturing has been receiving much attention.

For example, in the additive manufacturing process using a metal foil raw material disclosed in the existing literature, the foil is used to replace metal powder for laser melting molding, which is similar to the laser powder bed molding process in nature, and the problems of thermal stress and material compatibility of the material cannot be solved by melting the material layer by means of a high-power laser. The integrated laser cutting and lamination station described therein can result in laser cleaving of the formed part to compromise performance. Moreover, the absorption rate of the smooth surface of the metal foil to laser is very limited, and the forming effect is not good. Also like the metal foil gluing direct additive molding technology related to patent document (publication number: CN 111843184a), this scheme relies on the mold and uses structural glue to bond the metal foil, the molding efficiency is low and there is no strength along the stacking direction, the practical industrial value is limited, and none of the above schemes has the ability to produce support, complex parts cannot be molded, the applicability is poor, highly complex parts cannot be printed, and the strength in the stacking direction is also poor. Meanwhile, the existing support structure is not easy to remove, and the problem that the overall entity is damaged easily to influence the processing precision is solved.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides the additive manufacturing method of the metal part, and solves the problem of how to realize quick support removal and improve the strength performance of the metal part.

The invention aims to realize the following technical scheme, and the method for manufacturing the metal part by the additive comprises the following steps:

A. conveying the metal foil to a cutting platform through a feeding system, cutting according to a cutting path pre-introduced by a high-energy beam cutting system, cutting through the high-energy beam cutting system to obtain corresponding metal foil slices, cutting according to the cutting path to generate solid parts with shapes corresponding to the two-dimensional cross sections of each layer of the metal part, directly using non-part solid parts of the metal foil slices as supporting materials, and cutting layer by layer according to the two-dimensional cross section shapes of the metal part;

B. transferring the whole single-layer metal foil slice cut according to the cutting path each time, then carrying out next cutting, and transferring each layer of metal foil slice cut on the cutting platform to the stacking platform;

C. spraying glue on the surface of the solid part corresponding to each layer of the two-dimensional shape of the metal part in each transferred metal foil slice, stacking the metal foil slice on the cutting platform of the next layer on the surface of the metal foil slice of the previous layer after spraying glue, and repeating the stacking process from the step A to the step C until a corresponding metal part blank is formed;

D. after non-solid part supporting materials of the stacked metal foil slices are removed, embedding metal part blanks into refractory powder, performing glue removal treatment in a diffusion welding furnace, and then heating and sintering for diffusion welding treatment to obtain corresponding finished metal parts.

The invention adopts the metal foil formed by high-energy beam cutting treatment, which is equivalent to that the size of the metal foil at each time is larger than the size of the entity part of the equivalent metal part, so that the cutting process and the stacking process are separated in the printing process, the cutting and damage effects of a high-energy beam source on the stacked materials below the metal foil can be effectively avoided, the metal foil of the entity part and the non-entity part which are cut is integrally transferred, namely the metal slices of the part area and the non-element area are not needed to be distinguished in the transferring process, so that modeling and generation of support are not needed to be considered, the foil of the area of the non-element part directly plays a supporting role in the stacking bin, the indiscriminate printing of a suspension structure with any complexity can be better realized, and in the stacking process, the entity part of each layer of metal foil is stacked after glue spraying, so that the realization can not generate displacement, the support material of the non-solid part is not sprayed with glue, can be smoothly removed in post treatment, and can be removed by directly falling off, in the cutting process, the foil pieces in the non-part area are cut into grid-shaped small blocks, so that the formed foil pieces can fall off conveniently, and the metal part blank of the solid part is embedded into refractory material powder, so that the stress uniformity in all directions is good, the support effect can be achieved, and the collapse prevention effect can be achieved on parts with complex suspension structures; and through arranging glue earlier, rethread diffusion welding handles, can effectually guarantee that the combination between the layer is inseparable, be favorable to going on of diffusion welding between the layer, realize the inseparable combination of metal foil interlaminar metal bond, mechanical properties is unanimous with fine and close block metal on making the direction of stacking of shaped material, and can also make the bad material of metal part sinter at the material high temperature, the material has diffusion rate fast under sintering temperature, and can maintain the material solid phase and avoid melting or deformation, improve holistic performance, make to have excellent mechanical properties, the microstructure is tiny compact, all have the effect of high strength in along stacking direction and perpendicular stacking direction.

In the additive manufacturing method of the metal part, preferably, the step a further includes performing discretization cutting on the non-metal part solid portion of each layer of the metal foil slices by using a high-energy beam cutting system to form grid-shaped fragments, where the high-energy beam cutting system is a laser cutting system. Carry out the discretization ionization cutting to the metallic foil section on every layer, through carrying out the discretization cutting to the metallic foil section of non-metallic part promptly, form relatively less piece through the cutting, can make the aftertreatment in-process, the desorption is more easy, and better reduction supports the desorption in-process and causes destruction or extrusion deformation etc. to entity part, improves holistic precision quality. The path of the discretized dicing described above may be cut according to a previously introduced dicing path. As a further preference, the shape of the grid-like patches is selected from squares, rectangles, diamonds or triangles. Smaller discretized chips are formed, removal is facilitated, particularly for overhanging metal parts, the metal parts cannot be blocked by the structure of the solid parts, removal is facilitated, the precision of the solid parts of the metal parts is not affected, and particularly for narrow non-part solid part regions surrounded by the region of the solid parts of the metal parts, a finer cutting grid can be adopted.

In the additive manufacturing method of metal parts, preferably, the cut metal foil piece is adsorbed on the surface of the cutting platform in step a by electrostatic adsorption. The metal foil sheet is equivalently opened and closed through electrostatic adsorption, the metal foil sheet is grabbed and released, the whole metal foil sheet of the cut solid part and the non-solid part is equivalently tightly attached to the upper platform of the cutting platform under the action of electrostatic adsorption, so that the metal slice cannot generate relative displacement, and the printing precision of the metal part is more effectively ensured.

In the additive manufacturing method of the metal part, preferably, in the step C, the glue spraying is specifically: and spraying glue on the circumferential surface, close to the edge, of the solid part of each layer of the two-dimensional shape of the metal part on the metal foil slice. The metal foil pieces of the entity parts on each layer can be effectively bonded together, so that the relative displacement is avoided, the printing precision is improved, and meanwhile, the overall glue spraying amount can be reduced, the follow-up glue discharging is realized, the tightness between each layer is more effectively ensured, the diffusion welding is facilitated, and the printed metal parts have better mechanical strength performance.

In the additive manufacturing method of the metal part, preferably, in the step a, the cutting platform transfers the cut metal foil slices to the stacking platform by turning over, and then the electrostatic adsorption is turned off so that the corresponding metal foil slices are separated from the cutting platform and stacked on the stacking platform. The stacking platform is directly turned over in the electrostatic adsorption state, stacking accuracy can be better improved, the whole positions of the non-solid part and the solid part after cutting can be basically unchanged, supporting stability and accuracy can be improved, and printing accuracy and effect can be improved. The cutting platform with the overturning structure can be realized by adopting a common overturning structure.

In the additive manufacturing method of a metal part, preferably, the cutting path of the cutting and the glue spraying path of the glue spraying are both generated in advance as path plans, and the cutting and the glue spraying are performed synchronously. Go on in step, more be favorable to controlling, and can be better make spout gluey process go on along the direction and the shape of cutting route, more be favorable to guaranteeing to spout gluey at the every solid portion's of corresponding round.

In the additive manufacturing method of metal parts, preferably, in step D, the refractory powder is one or a mixture of two selected from corundum powder and graphite powder. The powder can better ensure that the blank of the metal part embedded in the powder has uniform stress in all directions, and the refractory powder also has a supporting function.

In the additive manufacturing method of the metal part, preferably, the metal part blank in the step D is placed in a diffusion welding furnace, the metal part blank is completely embedded in refractory powder, the top end of the metal part is pressed by a pressing rod to perform interlayer compaction, the pressure is controlled to be 10-15 MPa, and the minimum distance between the metal part blank and any side wall of any diffusion welding furnace is 15-25 cm. The metal parts are pressed in the stacking direction by pressurizing, so that the layers are more tightly attached, and the mechanical property of the metal parts after diffusion welding is improved.

In the additive manufacturing method of the metal part, the temperature of the rubber discharge in the step D is preferably 300-400 ℃; the sintering temperature is 1200-1300 ℃. The sprayed adhesive can be effectively discharged and removed, and the tightness between layers is further improved.

In summary, compared with the prior art, the invention has the following advantages:

1. the metal foils with the cut solid parts and the non-solid parts are integrally transferred, the regional foils of the non-part parts directly play a supporting role in the stacking bin, the indiscriminate printing of a suspension structure with any complexity can be better realized, the solid parts of the metal foils on each layer are stacked after glue spraying in the stacking process, the metal foils can be smoothly removed in post treatment and can be directly removed by falling off, the solid phase of the material can be maintained by diffusion welding treatment to avoid melting or deformation, the integral performance is improved, the metal foils have excellent mechanical properties, the microstructure is fine and compact, and the metal foils have high-strength effects in the stacking direction and the vertical direction.

2. Through the whole transfer of the entity part with metal foil and non-entity part, and carry out the discrete aftertreatment to the metal foil section of non-entity part, form littleer discrete piece, more be favorable to the desorption, especially to the metal part that dangles, make can not blockked by the structure of entity part, more relaxed getting rid of, do not influence the precision of metal part entity part again, improve holistic precision quality effect.

Drawings

Fig. 1 is a schematic structural view of a three-dimensional model of a biconical hollow structure of the manufacturing method of the metal part additive.

Fig. 2 is a schematic view of the overall structure formed by stacking the cut metal foil slices by the method of the present invention.

Fig. 3 is a schematic diagram of a cut single-layer metal foil in the method of the present invention after cutting.

Fig. 4 is a schematic view of the overall flow structure of the manufacturing method of the metal part additive.

Fig. 5 is a schematic view of a metal part blank after embedding refractory powder in the metal part additive manufacturing method of the present invention.

Fig. 6 is a schematic diagram of a three-dimensional model structure of an inverted conical hollow structure of the manufacturing method of the metal part additive.

Fig. 7 is a schematic view of another overall structure formed by stacking cut metal foil slices by the method of the present invention.

1. A feeding system; 11. a feeding roller; 12. a material receiving roller; 2. cutting the platform; 21. a screw rod; 22. a turning shaft; 3. stacking the platforms; 4. a high energy beam cutting system; 5. slicing the metal foil; 51. a metal part blank; 52. a support material; 6. a refractory powder; 7. a glue spraying system; 71. a glue spraying head 8 and a mandril; 9. a glue discharging valve.

Detailed Description

The technical solutions of the present invention will be further specifically described below with reference to specific examples and drawings, but the present invention is not limited to these examples.

Referring to fig. 1-5, the additive manufacturing method of the metal part includes that the metal foil is conveyed to a cutting platform through a feeding system 1, wherein the feeding system generally enables a coiled material of the metal foil to be placed into a feeding roller 11 and then conveyed under the driving of a receiving roller 12; the metal foil is conveyed to a corresponding cutting platform 2 for cutting; the metal foil is used as a raw material, so that the processing is more facilitated, the thickness of the metal foil is preferably reduced to less than 10 micrometers, and the width of the metal foil can be freely adjusted based on the requirements of the size of a processed metal part and the utilization rate of the metal foil. Suitable materials for the metal foil include any metal material capable of being diffusion bonded, and the metal foil material can be pure metal or alloy. Preferably, the metal foil material is selected from iron-based alloy, aluminum-based alloy, cobalt-based alloy, titanium-based alloy or pure metals thereof, and further, the surface of the metal foil material can be sprayed with soldering flux or an interlayer to improve the welding performance. The moving speed of the metal foil of the feeding system 1 is preferably controlled to be 0.1 to 0.4 m/s.

On the cutting platform 2, cutting according to a cutting path pre-introduced by the high-energy beam cutting system 4, preferably cutting by a laser cutting system to obtain a corresponding metal foil slice 5, cutting according to the cutting path to generate a solid part with a shape corresponding to the two-dimensional cross section of each layer of the metal part, directly using the non-part solid part of the metal foil slice 5 as a supporting material 52, and cutting layer by layer according to the two-dimensional cross section shape of the metal part; the cutting path which is pre-introduced can be equivalent to digital modeling by establishing a three-dimensional model of a metal part to be processed, discretization processing is carried out according to three-dimensional software, layered slices are designed, the size of the dimension can be adjusted according to actual conditions, the cutting path of the layered slices is led out to a program of a laser cutting control system, the laser cutting control system can read all the introduced slice outlines and generate corresponding cutting paths, and the laser cutting control system cuts according to the introduced cutting paths; the method also comprises the steps of cutting the corresponding metal foil firstly, and then cutting the cutting path of the corresponding solid part of each layer on the metal foil slice 5, so that the metal foil slice 5 of each layer corresponds to the solid part and the non-solid part; corresponding to the size of the metal foil slice 5 of each layer being larger than the size of the solid part of the respective layer. Further, still make laser cutting control system to every layer of foil section 5 the regional grid of the cross cutting lines of regular cross cutting lines of generating of non-part entity portion, if can be square, rectangle, rhombus or triangle-shaped etc. carry out the discretization cutting, can make it easily get rid of after whole stacking is accomplished, and do not blockked by entity part's structure, improve the precision effect of printing, in addition, to complicated part, if to the region of the narrow non-metal part entity portion that is encircleed by part entity region, can carry out the cutting grid that refines more and carry out the discretization and handle, make the desorption of more effective entity non-metal part entity portion. The cutting path corresponding to each layer in the laser cutting control system is stored in the control system, and the cutting path is automatically called and executed layer by layer, wherein the equipment of the laser cutting control system is common equipment. As a further preferred scheme, preferably, the laser light source in the laser cutting control system is a pulse laser, under the control of the computer, the laser is discharged by pulses, so as to output a controlled pulse laser with repeated high frequency, form a beam with certain frequency and certain pulse width, the pulse laser beam is conducted and reflected through the optical path and focused on the surface of the processed object through the focusing lens group to form a fine and high-energy-density light spot, and the focal spot is located near the surface to be processed to melt or gasify the processed material at an instant high temperature. Each high-energy laser pulse instantly sputters a small hole on the surface of the object, cuts the metal foil on the cutting platform 2 under the control of a computer and a galvanometer to form a corresponding metal foil slice 5 and forms a corresponding solid part and a non-solid part by cutting. Of course, the high-energy beam may be a high-energy beam cutting system including a common industrial cutting light source such as ultraviolet light, an electric arc, a plasma gun or an electron beam. The cutting speed and power can be adjusted according to materials, the metal foil is very thin, the requirement on laser energy is low and can be generally within 20 watts, the production cost of the whole equipment is effectively reduced, the cutting speed of laser cutting is preferably controlled to be 10-15 m/s, the size of a grid formed by cutting a non-part solid part can be adjusted according to actual requirements, for example, the side length of a square can be 10-15 mm, the side length of a diamond can be 10-15 mm, the glue spraying speed of glue spraying is preferably 0.1-0.3 m/s, and the glue spraying thickness is 3-6 mu m.

Each layer of cut metal foil slice 5 is preferably adsorbed on the cutting platform 2 in an electrostatic adsorption mode, and each layer of cut metal foil slice 5 is transferred to the corresponding stacking platform 3 from the cutting platform 2 through the transfer mechanism; the transfer mechanism can be realized by adopting a turning structure which is commonly used in a mechanical structure. The stacking platform 3 is used for stacking the cut metal foil 5 cut on the cutting platform 2 layer by layer to form a corresponding metal part blank 51.

Every layer of foil section 5 that shifts to the stacking platform from cutting platform 2 on the layer-by-layer adopts and spouts gluey system 7 to spout gluey processing and makes 5 surfaces at every layer of foil section spout the adhesive, and every layer of foil section 5 that shifts to stacking platform 3 spouts gluey on the surface of the entity part that corresponds, makes every layer of foil section 5 after the pile better prevent to produce the displacement, improves the effect of whole precision. Further preferably, the glue spraying system 7 for glue spraying treatment can generate a glue spraying path according to a layer-by-layer two-dimensional slice shape and a laser cutting pattern path of a corresponding metal part, the specific glue spraying strategy is preferably to continuously spray glue along the circumferential direction of the outline of the part of the solid part corresponding to the metal part, and each grid cut block of the area of the support material 52 of the non-part solid part outside the solid part corresponding to the metal part can also preferably perform one-time glue spraying to improve the stability of the support part, and the glue spraying mode can ensure the effective removal of the support part, further, the high-precision glue spraying head 71 is preferably adopted to ensure that the width of the spraying line is less than 1 mm, and the thickness of the spraying layer of the glue is preferably less than one tenth of the thickness of the metal foil slice 55, for an overhung structure with excessive weight, the glue spraying system 7 can improve the binding force by automatically and properly increasing the glue spraying amount and glue spraying width, can prevent the support from being broken after being removed. If the weight of the suspension structure exceeds the bonding capacity, the solid support is added as a part of the part in the molding process, all judgment can be processed by the control system, the glue spraying path is generated and then stored in a memory of a control computer, and the suspension structure is automatically taken and executed layer by layer in the printing process.

Further, it is preferable that the cutting operation is performed by the cutting table 2, and the surface of the solid portion of the cut metal foil 5 on the stacking table 3 is subjected to a glue spraying operation, wherein the glue spraying head 71 for spraying glue is driven and positioned by a conventional XYZ three-axis guide rail to perform a three-dimensional driving and positioning, and wherein the glue spraying path reads data stored in advance in a control system such as a control computer to perform the operation.

The height of the feeding roller 11 and the receiving roller 12 in the feeding system 1 is preferably adjusted to a suitable position so that the metal foil can be substantially attached to the cutting platform 2, so that the cutting platform 2 is kept horizontal and electrostatic adsorption is applied after the metal foil is in the correct position, and the metal foil is adsorbed on the cutting platform 2 under electrostatic action, for example, by electrostatic adsorption on the cutting platform 2. Here, a thermal insulating material having a low energy absorption rate for high energy beams such as laser beams is used as the material of the cutting table 2, and the cutting table 2 is preferably made of a ceramic material. The surface that the aforesaid is equivalent to cutting platform 2 comprises electrostatic chuck, and foil section 5 can tightly be attached on cutting platform 2 under the effect of static, and relative displacement is taken place in more effectual avoiding, improves the precision effect that the part printed and processed.

In a better scheme, after the cutting of each layer of metal foil slices 5 is finished, the metal foil slices 5 are kept to be electrostatically opened, namely the metal foil slices 5 corresponding to electrostatic adsorption are kept, a substrate of the cutting platform 2 is driven by the screw rod 21 to sink downwards to a certain height to be flush with the stacking platform 3, in the sinking process, the surface of the cutting platform 2 is separated from uncut metal foil materials, the cut metal foil slices 5 are kept attached to the cutting platform 2 under the action of static electricity and gravity, after the cutting platform 2 descends to a specified height, the cut metal foil slices 5 can be transferred to the stacking platform 3 at an adjacent position by overturning along the overturning shaft 22, after the cutting platform 2 is overturned for 180 degrees, the electrostatic adsorption is forbidden, the corresponding metal foil slices 5 are separated from electrostatic adsorption, and the cut metal foil slices 5 are smoothly transferred to the stacking platform 3, then the cutting platform 2 is turned over and returned and moves upwards to the initial height, the height is consistent with the corresponding plane of the metal foil, meanwhile, the stacking platform 3 descends to a position equivalent to the thickness of 5 layers of metal foil slices, and the next layer of metal foil slices 5 are turned and stacked;

all of the above steps of feeding, cutting, transferring and spraying glue and stacking are repeated until the cutting and stacking of the cut pieces of metal parts is completed to form the entire metal part blank 51, which may be processed through full automation and automation.

Taking the stack of the metal part blanks 51 formed after the stacking from the forming bin, removing all non-solid supporting materials 52, putting the corresponding stacked solid metal part blanks 51 into a columnar refractory alloy container, pouring refractory powders 6 such as corundum powder, graphite powder and other refractory powders 6 into the container, wherein the amount of the refractory powders 6 added is that the corresponding metal part blanks 51 are completely immersed in the refractory alloy container, putting the container containing the metal part blanks 51 and the refractory powders 6 into a diffusion welding furnace, opening a degreasing valve 9 to carry out heating degreasing, preferably controlling the temperature at 300-400 ℃ to carry out glue discharging, preferably at 350 ℃, closing the degreasing valve 9 after completely removing the binder, preferably starting longitudinal pressure on the materials in the container by sliding down of a mandril 8, and making the cross section of the mandril completely consistent with the shape of an opening at the upper end of the container, and downwards pressurizing to 10-20 MPa, heating to the sintering temperature of the material, preferably pressurizing under the pressure of 15MPa, controlling the sintering temperature to be 1200-1300 ℃ for diffusion welding treatment, preferably 1250 ℃, maintaining for a certain time, preferably 1-2 hours, and then completing diffusion welding of the stacked metal foil blanks, wherein the optimal parameter of the diffusion welding of the metal foil can maximize the diffusion quantity of material atoms and can effectively prevent grain coarsening caused by overheating. Furthermore, the diffusion welding furnace after glue discharging is processed in an inert gas or vacuum state, so that foil materials can be effectively prevented from being oxidized, and the welding performance is improved. The diffusion welding treatment can also be performed in a hot isostatic pressing furnace after the binder removal.

Example 1

The results are shown in FIGS. 1-5, and a further preferred embodiment is as follows: the present embodiment is implemented by processing a metal part with a complex structure with a specific structure, here, taking 316L stainless steel foil as an example, so as to implement the processing of a bicone structure shown in fig. 2 by additive manufacturing, where the structure includes a hollow structure and a suspension structure, and for better illustration, the following are specifically implemented: the manufacturing method of the metal part additive is realized by the following steps:

the method comprises preparing a digital model of the metal part by using conventional modeling software (such as UG modeling software), wherein the model has a height of 95mm and a maximum width of 85mm, layering the CAM model by using layering software, wherein the layer thickness needs to be consistent with the layer thickness of a foil material, namely 50 μm, and about 1900 layers in total, introducing the CAM model into a program of a laser cutting control system, and respectively generating a corresponding cutting laser cutting path and a glue spraying path for spraying glue by using a laser cutting control system and a glue spraying system 7, wherein the glue for spraying the glue can adopt an aqueous wax emulsion organic high molecular adhesive, has good fluidity, low viscosity and easy atomization, can be better sprayed on the surface of the metal foil slice 5, the laser cutting adopts pulse laser to cut, the cutting power of the pulse laser is 15W, the cutting rate of the laser cutting is 10m/s, and the non-part area corresponding to the metal foil slice 5 is subjected to discretization by adopting square grid cutting division, the size of the grid is 15 mm; in addition, the glue spraying speed is 0.1m/s, and the glue spraying thickness is 5 μm.

Referring to fig. 4, the electrostatic adsorption on the cutting platform 2 is turned on, and meanwhile, the feeding system 1 moves the 316L stainless steel metal foil horizontally under the action of the feeding roller 11 and the receiving roller 12, so that the moving speed of the 316L stainless steel metal foil is set to 0.2m/s, and the metal foil on the corresponding cutting platform 2 can be adsorbed on the surface by the electrostatic adsorption.

Here, the cutting operation of the cutting platform 2 and the glue spraying operation of the corresponding glue spraying system 7 on the stacking platform 3 are performed synchronously, the corresponding cutting path and the glue spraying path can be read from a pre-generated path plan in real time, cutting is performed by being pre-imported into a program of a laser cutting control system, and the glue spraying path can be performed synchronously.

Particularly, after the first layer 316L stainless steel metal foil is cut to form the corresponding metal foil slice 5, the cut sheet of 316L stainless steel metal foil 5 herein is cut to form solid portions and corresponding non-solid portions of the corresponding metal parts, the corresponding cutting platform drives the cutting platform 2 to sink for a certain height through the screw rod 21, the downward moving speed of the platform is 0.1m/s, when the cutting platform reaches the same height of the stacking platform 3, the turning shaft 22 of the cutting platform 2 is started to work, the turnover shaft 22 is used for turnover 180 degrees and transferring the turnover angle to the stacking platform 3, the turnover angle speed is 30 degrees/s, the electrostatic adsorption is kept on during turnover, the cut 316L stainless steel metal foil slices 5 are adhered to the stacking platform 3, and the glue spraying is performed synchronously, the first cut metal foil 5 on the stacking platform 3 is adhered to the surface by the corresponding adhesive sprayed on the stacking platform 3.

And (3) closing the electrostatic adsorption effect, and respectively driving the cutting platform 2 to recover to the initial station by the turnover shaft 22 and the screw rod 21. The stacking platform 3 is correspondingly lowered by a layer thickness height, i.e. 50 μm, and the cut foil sections 5 are stacked on top of each other.

Repeating the steps of feeding, cutting, turning, glue spraying, stacking and the like until the part is completely molded to form a corresponding metal part blank 51;

referring to fig. 5, transferring the metal part blank 51 from the stacking platform 3, after removing the support (corresponding to removing the metal foil of the corresponding non-solid portion), completely embedding the corresponding metal part blank 51 into a diffusion furnace containing refractory powder 6 (the refractory powder is a mixture of corundum powder with a particle size of 100 μm and graphite powder with a particle size of 100 μm, and the mass ratio of the corundum powder to the graphite powder is 1: 1), ensuring that the minimum distance between the corresponding metal part blank 51 and the side wall on either side of the diffusion furnace is 20cm, and the top of the metal part blank 51 is at least 20cm higher than the refractory powder 6, then opening a glue discharging valve 9 of the diffusion furnace and heating to 350 ℃ at a heating rate of 5 ℃/sec for glue discharging treatment for 45 minutes;

and after the glue discharging treatment is finished, closing the glue discharging valve 9, heating the diffusion welding furnace to the sintering temperature of 1250 ℃ at the heating speed of 10 ℃/min in a vacuum state, pressing the diffusion welding furnace by 15MPa through the ejector rod 8 at the top end, effectively ensuring tight interlayer bonding, keeping the temperature for diffusion welding treatment for 90 min, taking out the part after cooling, and carrying out air cooling to obtain a corresponding metal part product. Corresponding performance tests show that the double-cone metal part has excellent mechanical properties, and has tensile strength of 495MPa in the stacking direction and strength of 480MPa in the direction perpendicular to the stacking direction. The microstructure is fine and compact, and the precision is high.

Example 2

The results are shown in FIGS. 4, 6 and 7, and further preferred embodiments are as follows: in the present embodiment, a part of an inverted cone structure shown in fig. 3 is manufactured by processing a metal part of a complex structure with a specific structure, here, taking 316L stainless steel foil as an example, and the structure includes an overhanging structure, which is specifically described as follows for better explanation: the manufacturing method of the metal part additive is realized by the following steps:

comprises preparing a digital model of the part by using modeling software (such as UG modeling software), wherein the model has a height of 95mm and a maximum width of 85mm, layering the CAM model by using layering software, wherein the layer thickness is required to be consistent with the layer thickness of the foil, namely 50 mu m, and about 1900 layers in total, the laser cutting system and the glue spraying system 7 are used for respectively generating a corresponding cutting laser cutting path and a corresponding glue spraying path, the glue for glue spraying can adopt a water-based wax emulsion organic polymer binder, has good fluidity and low viscosity, is easy to atomize, can be better sprayed on the surface of the metal foil slice, the laser cutting here uses a pulsed laser for cutting, the pulsed laser cutting power is 18W, the cutting speed of the laser cutting is 12m/s, the non-part area corresponding to the metal foil section 5 is divided by rhombic grid cutting, and the grid size is 15 mm. The glue spraying speed is 0.2m/s, and the glue spraying thickness is 5 mu m.

The electrostatic adsorption on the cutting platform 2 is started, and meanwhile, the 316L stainless steel foil horizontally moves under the action of the feeding roller 11 and the receiving roller towards the cylinder 12 through the feeding system 1, so that the moving speed of the metal foil is set to be 0.2m/s, and the metal foil on the corresponding cutting platform 2 can be adsorbed on the surface through the electrostatic adsorption.

Here, the cutting action of the cutting platform 2 and the corresponding glue spraying action on the stacking platform 3 are performed synchronously, the corresponding cutting and glue spraying paths are read from a pre-generated path plan in real time, cutting is performed through a program which is pre-imported into a laser cutting system, and the glue spraying paths can be performed synchronously.

Specifically, after the first-layer stainless steel foil is cut to form the corresponding metal foil slice 5, the metal foil slice 5 is cut to form the solid part and the corresponding non-solid part of the corresponding part, the corresponding cutting platform is driven by the lead screw 21 to sink to a certain height, the platform moving speed is 0.2m/s, after the same height of the stacking platform is reached, the turning shaft 22 of the cutting platform 2 is opened to work, turning is performed by 180 degrees, the turning angle speed is 30 degrees/s, electrostatic adsorption is kept on during turning, the cut metal foil slice 5 made of the stainless steel is adhered to the stacking platform, and the adhesive is sprayed on the stacking platform 3 correspondingly due to synchronous action of the adhesive, so that the first-layer metal foil slice 5 on the stacking platform 3 is adhered to the surface.

And (3) closing the electrostatic adsorption effect, and driving the cutting platform 2 to return to the initial station by the turnover shaft 22 and the screw rod 21. The cutting platform 2 is lowered by a height of one layer thickness, i.e. 50 μm.

Repeating the steps of material conveying, cutting, turning, glue spraying and the like until the part is completely molded to form a corresponding metal part blank 51;

transferring the metal part blank 51 from the stacking platform 3, after removing the support (which is equivalent to removing the corresponding non-solid metal foil), completely embedding the corresponding metal part blank 51 into a diffusion furnace containing refractory powder 6 (the refractory powder is mixture of corundum powder with the particle size of 100 microns and graphite powder with the particle size of 100 microns, and the mass ratio of the corundum powder to the graphite powder is 2: 1), ensuring that the minimum distance between the corresponding metal part blank 51 and the side wall on any side of the diffusion welding furnace is 20cm, and the top of the metal part blank 51 is at least 25cm submerged by the refractory powder 6, then opening a glue discharging valve 9 of the diffusion welding furnace and heating to 400 ℃ at the heating rate of 8 ℃/s for glue discharging treatment for 50 minutes;

and after the glue discharging treatment is finished, closing the glue discharging valve 9, heating the diffusion welding furnace to 1300 ℃ at a heating speed of 15 ℃/min under a vacuum state, pressing the diffusion welding furnace downwards at 15MPa through the ejector rod 8 for compaction, effectively ensuring tight interlayer bonding, keeping the temperature for diffusion welding treatment for 80 min, cooling, taking out the part, and performing air cooling to obtain a corresponding inverted cone-shaped metal part product. Corresponding performance tests are carried out, and the result shows that the inverted cone-shaped metal part has excellent mechanical properties, the tensile strength in the stacking direction is 502MPa, the strength in the vertical stacking direction is 489MPa, the microstructure is fine and compact, and the precision is high.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments, or alternatives may be employed, by those skilled in the art, without departing from the spirit or ambit of the invention as defined in the appended claims.

While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.

Claims (10)

1. A method of additive manufacturing of a metal part, the method comprising the steps of:

A. conveying a metal foil material onto a cutting platform (2) through a feeding system (1), cutting according to a cutting path pre-introduced by a high-energy beam cutting system (4), cutting through the high-energy beam cutting system (4) to obtain corresponding metal foil slices (5), cutting according to the cutting path to generate solid parts with shapes corresponding to two-dimensional cross sections of each layer of the metal part, directly using non-part solid parts of the metal foil slices (5) as supporting materials (52), carrying out discretization cutting on the supporting materials (52) of the non-metal part solid parts of each layer of the metal foil slices (5) by adopting the high-energy beam cutting system (4) to form latticed fragments, and cutting layer by layer according to the two-dimensional cross section shapes of the metal part;

B. the whole single-layer metal foil slice (5) which is cut according to the cutting path each time is transferred firstly and then cut next time, and each layer of metal foil slice (5) which is cut on the cutting platform (2) is transferred to the stacking platform (3);

C. spraying glue on the surface of the solid part corresponding to each layer of the two-dimensional shape of the metal part in each transferred metal foil slice (5), stacking the metal foil slice (5) on the next layer of cutting platform (2) on the surface of the metal foil slice (5) on the previous layer after glue spraying, and repeating the stacking process from the step A to the step C until a corresponding metal part blank (51) is formed;

D. after removing the non-solid part support material (52) of the stacked metal foil slices (5), embedding a metal part blank (51) into refractory powder (6), carrying out glue removal treatment in a diffusion welding furnace, then heating and sintering for diffusion welding treatment, and obtaining a corresponding finished metal part.

2. The method for additive manufacturing of a metal part according to claim 1, wherein the high energy beam cutting system (4) in step a is a laser cutting system.

3. The method of additive manufacturing of a metal part according to claim 2, wherein the shape of the grid-shaped chips is selected from square, rectangular, diamond, or triangular.

4. The additive manufacturing method of the metal part according to claim 2, wherein the cut metal foil (5) is attached to the surface of the cutting platform (2) in step a by electrostatic adhesion.

5. The additive manufacturing method of the metal part according to any one of claims 1 to 4, wherein the glue spraying in the step C is specifically as follows: and spraying glue on the circumferential surface of the solid part close to the edge of each layer of the two-dimensional shape of the metal part on the metal foil slice (5).

6. The additive manufacturing method of the metal part according to claim 4, wherein the cutting platform (2) transfers the cut metal foil slices (5) to the stacking platform (3) by turning over in step A, and then the electrostatic adsorption is turned off to enable the corresponding metal foil slices (5) to be separated from the cutting platform (2) and stacked on the stacking platform (3).

7. The method for additive manufacturing of a metal part according to any one of claims 1-4 and 6, wherein the cutting path of the cutting and the glue spraying path of the glue spraying are both planned through a pre-generated path, the cutting being performed synchronously with the glue spraying.

8. Method for the additive manufacturing of a metal part according to any of claims 1-4 and 6, wherein in step D the refractory powder (6) is selected from one or a mixture of two of corundum powder and graphite powder.

9. The method for manufacturing the metal part by the additive according to any one of claims 1 to 4 and 6, wherein the metal part blank (51) in the step D is placed into a diffusion welding furnace, the metal part blank (51) is completely embedded into the refractory powder (6), the top end of the metal part blank (51) is pressed by a pressing rod (8) to carry out interlayer compaction, the pressure is controlled to be 10-15 MPa, and the minimum distance between the metal part blank (51) and any side wall of the diffusion welding furnace is 15-25 cm.

10. The additive manufacturing method of the metal part according to any one of claims 1 to 4 and 6, wherein the temperature of the rubber discharge in the step D is 300 ℃ to 400 ℃; the sintering temperature is 1200-1300 ℃.

Images