A kind of nano metal powder 3 D-printing forming method based on sensing heating
Technical field
The invention belongs to increases material manufacturing technology fields, and in particular to a kind of nano metal powder based on sensing heating is three-dimensional
Printing shaping method.
Background technology
3D printing (increasing material manufacturing) technology is actually a series of general designation of parts rapid shaping techniques, basic principle
All it is layered manufacturing, forms the cross sectional shape of workpiece by scanning form in X-Y plane by rapidform machine, and in Z coordinate
The displacement for discontinuously making slice thickness, ultimately forms three dimensional articles.Rapid shaping technique currently on the market be divided into 3DP technologies,
FDM melt-laminated molding technologies, SLA stereolithography techniques, SLS precinct laser sinterings, DLP laser forming technologies and UV are purple
Outside line forming technique etc..
Since the fusing point of metal is very high, the laser beam of high-energy density is needed for the 3D printing forming technique of metal material
Or electron beam is as heat source.With the development of science and technology with the needs of popularization and application, directly manufactured using laser gain material manufacture
Metal parts is increasingly paid close attention to by people.Laser gain material manufacture can be divided into following three kinds of quick forming methods:1. direct metal
Deposition technique;2. precinct laser sintering technology;3. selective laser melting process.
Direct metal deposition technology is to utilize general Quick-forming thought, and the gold of synchronous supply is melted using high power laser
Belong to powder, successively accumulates and formed the rapid prototyping technology of metal parts in deposition substrate using special nozzle.Direct metal
The essence of deposition technique is the three-dimensional stack shaping of computer control metal bath, and the technological problems of existing most serious are sharp
Light cladding layer tearing tendency is apparent, and the presence of crackle will greatly reduce the consistency of laser melting coating part.
Precinct laser sintering technology is selectively to be layered sintering solid powder using laser beam, laser beam in sintering process
Line by line, mobile carry out compartmentalization scanning successively, and so that the cured layer of thermal sintering is layering and generate the part of required shape,
Its entire technical process includes foundation and data processing, powdering, sintering and post-processing of CAD model etc..Precinct laser sintering
For technology during being sintered iron powder, temperature when acting on powder due to laser beam is relatively high, and energy ratio is larger, in forming process
In the layering of sinter layer easily occurs, to form spherodization and form bigger crackle.
The operation principle of selective laser melting process is similar to precinct laser sintering technology, and difference lies in precinct laser sinterings
When acting on powder, powder is not completely melted technology, and required drip molding is prepared into semi-molten state.Precinct laser is molten
Change technical role when powder, powder is made to be completely melt and solidify, swashs compared to constituency to the forming quality of drip molding
The drip molding that light sintering technology is prepared has significant raising.
Nano material refers at least one-dimensional in nanoscale range (1~100nm) or by them in three dimensions
The material constituted as basic unit.Studies have shown that nano-particle, since grain size is small, specific surface free energy is high, therefore its chemical potential
It is more much higher than the blocks of solid under the same terms, as a result cause the bulk that its fusing point and sintering temperature are significantly less than same material solid
Body, and the grain size of particle is smaller, fusing point and sintering temperature are lower.The fusion temperature of metal nanocrystal depends not only on crystal
Size also depends on the dimension (shape) of crystal simultaneously.To the crystal with same dimension, fusing point is dropped with the reduction of crystalline size
It is low;And the crystal of identical size, fusing point are also reduced with the reduction of dimension.
In the prior art, although all kinds of metal 3D printing techniques are substantially all is used as molding raw material using metal powder,
But its powder size is 100nm or more, and the irradiation by external high energy beam (laser beam or electron beam) is needed so that powder is molten
Coagulation forming, shortcoming have again after change:1) it needs to rely on single or multiple high energy beam linear scans in forming process, for
For each high energy beam, powder on scan path fusing-coagulation forming successively substantially cannot achieve parallel molding, because
This shaping speed is slow, efficiency is low;2) since the electro-optical efficiency of laser, electron beam source is low (being generally less than 20%), and
The fusing point of metal powder is very high so that is molded that required energy density is high, and actual energy consumption is very high;3) due to using micron
The high-melting-point characteristic of granularity metal powder, powder makes the processing qualities such as its molten bath metallurgy quality, molded surface roughness not high,
The defects of easy ting produce residual stress accumulation, thermal stress deformation, internal fire check;4) due to thermal stress deformation problem, molding zero
Part is size-constrained, otherwise can not obtain the molded part for meeting dimension precision requirement.
Invention content
The present invention in view of the above shortcomings of the prior art, it is three-dimensional to provide a kind of nano metal powder based on sensing heating
Printing shaping method.
The present invention is achieved through the following technical solutions:
A kind of nano metal powder 3 D-printing forming method based on sensing heating, includes the following steps:
(1) prepare CAD data file, shaping substrate, nano metal powder and the nanometer powder of 3 D-printing forming part
Spray array board;
The CAD data file of the 3 D-printing forming part is zero that processing and forming is treated using Three-dimensional CAD Software
Part carries out three-dimensional modeling, and adds auxiliary support structure according to the parts threedimensional model form factor of acquisition, then presses tradition
The layered manufacturing principle setting thickness of 3 D-printing carries out the closed outline graph data set obtained after hierarchy slicing;
The upper surface of the shaping substrate is plane and is required to the bottom of 3 D-printing forming part being sliced
Closed outline figure is included, and the material of the shaping substrate is metal or ceramic material, and the shaping substrate is with controllable
The heating device of temperature is to realize that the upper surface by shaping substrate is heated and maintained within the scope of set temperature;
The nano metal powder is molded for 3 D-printing, it is desirable that nano metal powder has temperature dimensional effect, gold
The fusing point for belonging to nanometer powder is less than the fusing point of shaping substrate;
It is provided with the parallel nozzle array for being combined and being constituted by multiple powder-feeding nozzles on the nanometer powder injection array board, is sent
Its cross-section of pipeline of the shape need of powder nozzle is arbitrary polygon or curve closed figure, the line size requirement of powder-feeding nozzle
Single nano metal powder of maximum particle diameter size without hindrance can pass through;Each powder-feeding nozzle is both provided with injection valve, uses
It closes and opens in controlling it;The exit end of each powder-feeding nozzle is both provided with an induction coil, the magnetic field center of induction coil
On the exit end central axis of powder-feeding nozzle;Nano metal powder goes out via the central-injection of the induction coil;Institute
It states and is both provided with magnetism servo-electric motor water-cooling inside powder-feeding nozzle and induction coil;
The exit end arrangement area of all powder-feeding nozzles is required to 3 D-printing being molded on the parallel nozzle array
In the closed outline figure of each hierarchy slicing of part is included in;
(2) the parallel nozzle array arrangement relationship of array board, the closed outline that every layer is sliced are sprayed according to nanometer powder
Figure carries out internal sectional type filling, and sectional type fill method is:It is that several are small by the inside division of closed outline figure
Block, it is desirable that the position of each small piecemeal is corresponding with the position of only one powder-feeding nozzle, i.e. block of cells and powder-feeding nozzle
Quantity and position are one-to-one relationship, and between the corresponding powder-feeding nozzle exit cross-section geometric center of small piecemeal barycenter
Line be mutually parallel;Corresponding with powder-feeding nozzle, the shape of block of cells is arbitrary polygon or curve closed figure, it is desirable that
The dimensioned area of each block of cells is respectively less than area setting, and the area setting refers to that nanometer powder melts in step (6)
Single layer flat spreading part product × (1- laps) afterwards, the lap are 10~50%;
(3) output port of shaping substrate, nanometer powder injection array board injection is placed in forming cavity room, the molding
For vacuum or close to vacuum in chamber, and air pressure is kept for being evacuated in real time with real-time vacuum-control(led) system;It is received described in it is required that
Rice powderject array board installation position so that parallel nozzle array is vertical with shaping substrate surface, and in (2) step
The block of cells position obtained after sectional type filling corresponds, i.e., the movement that nanometer powder is ejected via parallel powder-feeding nozzle
Direction vertical direction toward impact is in shaping substrate surface, for filling the respective cell block that sectional type is filled in (2) step;
(4) shaping substrate and molded part is made to remain at set temperature in forming process by heating, it is described
Set temperature requires below block fusing point, more than nano metal powder fusing point;The block fusing point refers to and metal nano powder
The fusing point of the identical common block metal material of powder material chemical composition, the i.e. fusing point without temperature dimensional effect;
(5) it regard the CAD data file bottom of 3 D-printing forming part slice as current slice;
(6) slice of data for obtaining current slice, according to the block of cells of its corresponding segmentation, corresponding powder feeding is opened in control
Nozzle injection valve is acted on so that metal nano powder by one or more composite drives of inert gas flow, magnetic field or electric field
End is flowed out via powder-feeding nozzle, passes through the heating of induction coil later, and temperature increases;Subsequent vertical direction toward impact working as in shaping substrate
Preceding molded surface is fallen in the block of cells of the sectional type filling corresponding to current molded surface;Due to current molded surface
Temperature is higher than the fusing point of nano metal powder so that rapid melting occurs in it, and automatic levelling is in block of cells;Again due to current
The temperature of molded surface not and its block fusing point, will not sent out simultaneously along with nano metal powder fusing, metal liquid levelling process
Raw setting effect, i.e. nano metal powder fuse one by fusing, levelling, solidification and current molded surface, and make its correspondence
Block of cells increase certain thickness;
(7) relative distance of adjustment shaping substrate and nanometer powder injection array board injection output port, cuts according to layering
The sequence of piece from bottom to top, it is current slice to take next slice;
(8) step (6)-(7) are repeated, the stacked in multi-layers of forming part from bottom to top are realized, until all points
All molding finishes layer.
The present invention has the advantages that:
1) present invention utilizes the temperature dimensional effect of nano metal powder, (grain size of particle is smaller, fusing point and sintering
Temperature is lower), using the unselected superfine nano metal powder of conventional method, metal parts forming temperature is greatly reduced,
It is ingenious that the technique for making shaping substrate and molded portion temperature below block fusing point, more than nano metal powder fusing point is utilized
Thought assists fuse effect without high energy beam, realizes the three-dimensional parts of hyperfine, ultrahigh speed based on nano metal powder three
Dimension molding (increasing material manufacturing).
2) present invention integrally heats shaping substrate and molded part in forming process, no shaping substrate and has become
The temperature gradient explained of type part eliminates traditional three-dimensionally shaped method of high energy beam scanning caused by temperature gradient is unavoidable
The defects of being molded thermal stress problem, while eliminating residual stress accumulation, thermal stress deformation, internal fire check.
3) present invention sprays the parallel injection molding of area array projection formula powder of array board using nanometer powder, to any single layer
All it is an injection molding, to which shaping speed has being greatly improved on the order of magnitude compared to conventional method;
4) for the present invention using nano metal powder as raw material, grain size is much smaller compared with conventional method, to molding layer
Thick precision is high, (theoretically surface roughness is about the half grain size of powder for molding to the reduction of surface of shaped parts roughness, therefore
The surface of shaped parts of nano metal powder is more smooth), processing quality is more preferable;Also, forming process, will not under low vacuum environment
Generate the molding environmental impact issues such as oxidation.
5) present invention can as needed be sent in forming process different powder (tube cell temporally, space allocation powder feeding kind
Class), so as to the component of any ingredients such as molding gradient material, dissimilar material and distribution, flexibly and easily, degree of freedom is big;
6) present invention is due to the defects of eliminating residual stress accumulation, thermal stress deformation, internal fire check problem so that at
Molded dimension is unrestricted, it can be achieved that large-scale part is molded;Also, the nano metal powder used is but also it compares tradition side
Method is more suitable for the three-dimensionally shaped of micro-nano small part, also can be used magnetic control coil converge effect, realize it is conformal scaling mapping at
Type, to further reduce compact dimensions, improve formed precision.
7) present invention employs high frequency electric field sensing heating effects, on the one hand realize the preheating of nano metal powder, promote
Into its rapid melting after reaching molded surface, molding rate can be effectively improved, on the other hand its strong alternating electric field is to molded
The molten drop levelling process on surface has strong function composite by electromagnetic stirring, may make that its metallurgical process is more uniformly abundant, has
It is more preferable conducive to problem, Forming Quality the defects of eliminating internal crystallization segregation, fire check.
Description of the drawings
Fig. 1 is the schematic diagram of powder-feeding nozzle, induction coil and shaping substrate;
Fig. 2 is grid jet arrays schematic diagram;
Fig. 3 is pipe grid jet arrays schematic diagram;
Specific implementation mode
The present invention will be further described in detail With reference to embodiment.
The present invention provides a kind of nano metal powder 3 D-printing forming method based on sensing heating, including walk as follows
Suddenly:
(1) prepare CAD data file, shaping substrate, nano metal powder and the nanometer powder of 3 D-printing forming part
Spray array board;
The CAD data file of the 3 D-printing forming part is using Three-dimensional CAD Software by designer to be formed
The parts of processing carry out three-dimensional modeling, and add necessary Auxiliary support according to the parts threedimensional model form factor of acquisition
Structure, then press the layered manufacturing principle setting thickness (the single flat laying after nanometer powder fusing is thick) of conventional three-dimensional printing into
The closed outline graph data set obtained after row hierarchy slicing;
The upper surface of the shaping substrate is plane and is required to the bottom of 3 D-printing forming part being sliced
Closed outline figure is included, and the material of the shaping substrate is the good metal of thermal conductivity or ceramic material, the molding
Heating device of the substrate with controllable temperature is to realize that the upper surface by shaping substrate is heated and maintained within the scope of set temperature.
Preferably, can also be used in the real-time contoured surface portion of 3 D-printing forming part follows induction coil real-time
It heats and temperature control is within the scope of set temperature.
The nano metal powder is molded for 3 D-printing, it is desirable that nano metal powder has temperature dimensional effect, allusion quotation
The powder for molding grain size of type is less than 100 nanometers (being less than the grain size threshold value with temperature scale effect), it is desirable that metal nano powder
The fusing point at end is less than the fusing point of substrate.
Preferably, nano metal powder itself band is magnetic or charge, can be by magnetic field or electric field acceleration.
As shown in Figure 1, be provided on nanometer powder injection array board be made of the combination of multiple powder-feeding nozzles 1 it is parallel
Nozzle array, its cross-section of pipeline of the shape need of powder-feeding nozzle 1 are arbitrary polygon or curve closed figure, powder-feeding nozzle 1
Line size require maximum particle diameter size single nano metal powder 5 without hindrance can pass through;Several powder-feeding nozzles 1
Shape and size may be the same or different;Each powder-feeding nozzle 1 is both provided with injection valve, for control its close with
Open, that is, control each powder-feeding nozzle 1 whether metal injection nanometer powder 5.
The exit end of each powder-feeding nozzle 1 is both provided with an induction coil 2, and the magnetic field center of induction coil 2 is located at powder feeding
On the exit end central axis of nozzle 1.Nano metal powder 5 goes out via the central-injection of the induction coil 2.The powder feeding
It is both provided with magnetism servo-electric motor water-cooling inside nozzle 1 and induction coil 2.
The exit end arrangement area of all powder-feeding nozzles 2 is required to 3 D-printing forming part on parallel nozzle array
Each hierarchy slicing closed outline figure be included in.
Typical nanometer powder injection array board has:Groined type grid jet arrays, honeycomb polygon, grid jet pipe battle array
Arrange (as shown in Figure 2), pipe grid jet arrays (as shown in Figure 3) etc..
After injection valve is opened, acted on by one or more composite drives of inert gas flow, magnetic field or electric field, metal
Powder 5 is ejected from the exit end of powder-feeding nozzle 1, is entered in the magnetic field of induction coil 2 later, is quickly felt by induction coil 2
It should heat, the induction coil 2 is connected with external high frequency or medium frequency induction power supply.
The carrier gas requires not chemically react with metal powder 5 at high temperature, generally inert gas, nitrogen
The mixing of gas, carbon dioxide or multiple gases.
(2) the parallel nozzle array arrangement relationship of array board, the closed outline that every layer is sliced are sprayed according to nanometer powder
Figure carries out internal sectional type filling, and sectional type fill method is:It is that several are small by the inside division of closed outline figure
Block, it is desirable that the position of each small piecemeal is corresponding with the position of only one powder-feeding nozzle, i.e. block of cells and powder-feeding nozzle
Quantity and position are one-to-one relationship, and small piecemeal barycenter (being assumed to be the equal slabs of uniform density, barycenter certainly exists) and
Line between its corresponding powder-feeding nozzle exit cross-section geometric center is mutually parallel;It is corresponding with powder-feeding nozzle, block of cells
Shape be arbitrary polygon or curve closed figure, it is desirable that the dimensioned area of each block of cells is respectively less than area setting,
The area setting refers to single layer flat spreading part product × (the 1- laps) after nanometer powder fusing, the overlapping in step (6)
Amount is 10~50%.Wherein, the single layer flat spreading part product in step (6) after nanometer powder fusing and nanometer powder in step (1) are molten
Single flat laying thickness after change can in advance be measured by experimental method.
(3) by shaping substrate 3, nanometer powder injection array board injection output port be placed in forming cavity room, it is described at
For vacuum or close to vacuum (air pressure is less than 100 Pascals) in cavity room, and real-time vacuum-control(led) system is carried, can taken out in real time
Gas keeps extremely low air pressure (being less than 100 Pascals);Due to nano metal powder jet drive power be inert gas or electromagnetic field,
Therefore require pumping in real time.
It is required that the installation position of the nanometer powder injection array board makes parallel nozzle array hang down with 3 surface of shaping substrate
Directly, and with the block of cells position obtained after sectional type filling in (2) step it corresponds, i.e., nanometer powder is via parallel powder feeding
The direction of motion vertical direction toward impact that nozzle ejects is in shaping substrate surface, for filling pair that sectional type is filled in (2) step
Answer block of cells.
Preferably, it is along gravity to make forming direction (direction of motion that nanometer powder is ejected via parallel powder-feeding nozzle)
Vertical direction, to avoid gravity Diffraction dispersion.
Preferably, vibration isolation processing is carried out to vacuum forming chamber, its Oscillation Amplitude is made to be not more than compact dimensions precision.
(4) shaping substrate 3 and molded part 4 is made to remain at set temperature in forming process by heating, institute
Set temperature is stated to require below block fusing point, more than nano metal powder fusing point;The block fusing point refers to and metal nano
The fusing point of the identical common block metal material of dusty material chemical composition, the i.e. fusing point without temperature dimensional effect.
(5) it regard the CAD data file bottom of 3 D-printing forming part slice as current slice;
(6) slice of data for obtaining current slice, according to the block of cells of its corresponding segmentation, corresponding powder feeding is opened in control
Nozzle injection valve is acted on so that metal nano powder by one or more composite drives of inert gas flow, magnetic field or electric field
End is flowed out via powder-feeding nozzle, passes through the heating of induction coil later, and temperature increases;Subsequent vertical direction toward impact working as in shaping substrate
Preceding molded surface is fallen in the block of cells of the sectional type filling corresponding to current molded surface;Due to current molded surface
Temperature is higher than the fusing point of nano metal powder so that rapid melting occurs in it, and automatic levelling is in block of cells;Again due to current
The temperature of molded surface not and its block fusing point, will not sent out simultaneously along with nano metal powder fusing, metal liquid levelling process
Raw setting effect, i.e. nano metal powder fuse one by fusing, levelling, solidification and current molded surface, and make its correspondence
Block of cells increase certain thickness;
Preferably, LCD panel display control similar with nanometer powder injection array board structural principle may be used
Principle, the output and closing of the parallel powder-feeding nozzle injection valve of face formation of control nanometer powder injection array board.
Preferably, if nano metal powder itself band is magnetic or charge, can apply magnetic field or electric field makes it in powder feeding
Nozzle 1 continues accelerated until hitting molded surface after flowing out.
(7) adjustment shaping substrate 3 and the relative distance of nanometer powder injection array board injection output port are (i.e. one mobile
Single layer is molded thickness, both keeps not touching and in the suitable injection molding distance range), according to hierarchy slicing from
To the sequence at top, it is current slice to take next slice for bottom.
(8) step (6)-(7) are repeated, the stacked in multi-layers of forming part from bottom to top are realized, until all points
All molding finishes layer.
The present invention can be changed apparent to one skilled in the art for various ways, and such change is not considered as
It departs from the scope of the present invention.The technical staff in the field is obviously changed as all, is included within this right
Within the scope of it is required that.