CN106111985A

CN106111985A - Group scan laser selective sintering or curing and 3D forming machine thereof

Info

Publication number: CN106111985A
Application number: CN201610264658.2A
Authority: CN
Inventors: 不公告发明人
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-05-07
Filing date: 2016-04-25
Publication date: 2016-11-16

Abstract

The invention belongs to electro-mechanical arts, paving powder sintering principle based on selective laser sintering, on the premise of can guarantee that formed precision and speed, use cheap and long-life semiconductor laser device, use laser array, carry out group scan method method: use the luminous point of multiple separate lasers to constitute laser spot array (20), form numerous micro scanning region (22)；Synchronization is generated by scan line (21).Moving range (amplitude) when laser spot, when being respectively equal to the light dot spacing in rows and columns direction, and in the case of the rate of scanning of row is much larger than the rate of scanning of row, this is that progressive scan state (is equivalent to the row-field scanning of CRT TV: the rate of scanning of row is higher, the rate of scanning of hardwood is relatively low), photoelectricity can cover all regions；It is specifically to be realized successively to the selective sintering method of dusty material and with the 3D forming machine manufactured by the method by group scan mode；Thus reduce manufacturing expense and the use cost of former greatly, and further improve shaping speed.

Description

Group scan laser selective sintering or curing and 3D forming machine thereof

[art]

The invention belongs to electro-mechanical arts, be specifically to realize successively choosing to dusty material by group scan mode Selecting property sintering (SLS) or solidification (SLA) method and with the 3D forming machine manufactured by the method.

[technical background]

Quick shaping process is developed so far the nearlyest 30 years, with Stereo Lithography (SLA) (Stereo Lithography Apparatus), selective laser sintering (SLS), fusion sediment (FDM), laminated solid body system Make (LOM) and 3D prints the forming method development that (3D-P) is representative and reaches its maturity, the commercial Application of multiple method Scope extends constantly, is accepted by increasing enterprise and approves.In the last few years, the grinding of rapid shaping Study carefully focus and be mainly moulding material and commercial Application.

Mainly there are DTM company, EOS Corp., Beijing Long Yuan company in the mechanism being engaged in SLS research at present in the world And the Central China University of Science and Technology.This technology relates to SLS Selective Laser Sintering, is to use laser to divide selectively Layer sintering solid powder, and make the cured layer of sinter molding be layering generate required form part. it is whole Technical process includes that the foundation of cad model and data process, spread powder, sintering and post processing etc.

Whole process unit is made up of feed powder cylinder and powder for molding cylinder, first, by the threedimensional model of part It is converted into STL formatted file, then by delamination software, it is carried out layered shaping, i.e. " discretization " process. Before starting processing, first forming room is preheated.During work, feed powder cylinder piston (powder feeding piston) rises, By powder-laying roller by powder at the upper uniform spreading last layer of powder for molding cylinder piston (working piston), computer is according to prototype Hierarchical model control laser beam two-dimensional scan track, sintering solid dusty material is to form part selectively An aspect. after powder completes one layer, working piston decline a thickness, paving powder system spread new powder. control Laser beam scans the new layer of sintering again. and so move in circles, be layering, until 3 d part molding. last, will not The Powder Recovery of sintering is in powder cylinder, and takes out profiled member. for laser sintering metallic powder, before sintering, Whole workbench is heated to uniform temperature, can reduce the thermal deformation in molding, and be beneficial to knot between layers Close. last, after the post processings such as polishing, drying, can complete and meet prototype or the part of demand.If Moulding material is metal dust, in addition it is also necessary to control the protection gas such as forming room's atmosphere, logical people's nitrogen, hydrogen, argon Body, to avoid metal dust at high temperature to aoxidize.

Theoretically, the most prominent for SLS advantage is that the moulding material that it is used is quite varied. from theory Upper theory, can form the dusty material of bonding between atom and can serve as the moulding material of SLS after any heating. At present, classify from material properties, metal dust, plastic powders and ceramic powders can be roughly divided into.Specifically may be used Select material include polystyrene powder, nylon powder, Merlon powder, Silon, wax powder, metal powder, Cover and wrap up in the glass dust of nylon, cover fat sand, propolizing ceramics, propolizing metal powder etc..Due to SLS forming material item Kind many, materials are saved, profiled member performance profile extensively, be suitable for multiple use and SLS without design and manufacture Complicated support system, so the application of SLS is more and more extensive.

SLA technique is similar with SLS；Its technical process is to be full of liquid bath with liquid photosensitive resin for material, by counting Calculation machine controls laser beam and follows the tracks of striped cross-sectional track, and the liquid resin being irradiated in liquid bath, and makes this layer of tree Fat solidifies, and lifting platform declines a layer height afterwards, in type aspect is covered with again one layer of resin, enters The row scanning of new one layer, one layer of new solidification is firmly sticked in preceding layer, so repeats until whole part system Make complete, obtain 1 three-dimensional entity model.

But the laser module of most of formers is relatively costly, because complicated high frequency vibrating mirror system is very Costliness, the convergence cost of dynamic beam is the highest, so using expensive and short-lived single high power laser conduct Energy source seriously hinders the popularization of rapid shaping technique.

[technical scheme]

The purpose of the present invention is that and overcomes current technology weak point, paving based on selective laser sintering Powder sintering principle, this paper presents on the premise of one can guarantee that formed precision and speed, uses cheap and long-lived The semiconductor laser device of life, thus reduce manufacturing expense and the use cost of former greatly, and also change It is apt to shaping speed.

Laser group scan method is the core of the inventive method:

With multiple independent low-power laser composition arrays, its luminous point focused on will constitute laser spot array (20), numerous micro scanning region (22) is formed；Synchronization is generated by scan line (21).When laser spot During the light dot spacing of moving range (amplitude), respectively equal to rows and columns direction, and when the rate of scanning of row is long-range In the case of the rate of scanning of row, this is that progressive scan state (is equivalent to the row-field scanning of CRT TV: row Rate of scanning is higher, and the rate of scanning of hardwood is relatively low), photoelectricity can cover all regions.

Due to group scan mode；If laser array is: MxN, it will make the rate of scanning in 2 directions subtract Few M and N times, amplitude also reduces M and N times, and the mechanical difficulty of driving greatly reduces, and galvanometer system becomes Obtain more easily, it might even be possible to directly use mechanical displacement driving to avoid complicated galvanometer system and focusing converges Poly-system, system stability is simple, and owing to the quantity of laser instrument is MXN, thus the merit of single laser instrument Rate is allowed to decline MN times；Semiconductor laser device, cost and life-span can be chosen further reduce, but It is noted that choose the conforming quality of semiconductor laser device, an advantage is also that the replacing of Laser Devices Also become easily；The numerical value of M, N can be that 2-200 is individual or more；Semiconductor device low cost, life-span are long Stable performance volume is little, and it is convenient to drive；Thus the machine of the desktop level of low cost miniaturization just becomes a reality.

The machinery of scanning realizes passing through, and rotating shaft reciprocating rotation mode (rotation drive-type), linear reciprocation are shaken Flowing mode (straight line driving), vibration mirror reflected mode (vibration mirror reflected formula).The most that mode, owing to shaking Width is the least, does not haves the excessive deviation liquid level of laser beam focus plane or the powder planar environment of powder groove.

Group scan method has 2 kinds: i.e. multizone dynamic balancing group scan method and single region group scan method:

Multizone dynamic balancing group scan method is that scanning area is divided into polylith isolated area, and each piece all in frequency Self-movement on that higher direction, and the phase place of motion is reverse, can offset vibration and inertia, it will obtain Obtain dynamic balancing well.

Single region group scan method: be the entire scan mode of a uniform areas, dynamic balancing can be by outside device Part is offset, to reduce vibration.

Other main working process of its 3D molding complete machine are: first, the threedimensional model of part is converted into STL Formatted file, then carries out layered shaping, i.e. " discretization " process by delamination software to it.Starting processing Before, first forming room is preheated.Computer i.e. drive circuit controls laser beam according to the hierarchical model of prototype Two-dimensional scan track, selectively sintering solid dusty material with formed part an aspect. powder completes After one layer, working piston declines a thickness, and paving powder system spreads new powder. and control laser beam and scan the new layer of sintering again. So move in circles, be layering, until 3 d part molding. last, by unsintered Powder Recovery to powder In cylinder, and take out profiled member. for laser sintering metallic powder, before sintering, whole workbench is heated to Uniform temperature, can reduce the thermal deformation in molding, and be beneficial to combination between layers. and last, through polishing, dry Do after waiting post processing, can complete and meet prototype or the part of demand.

If moulding material is metal dust, in addition it is also necessary to control forming room's atmosphere, logical people's nitrogen, hydrogen, argon Deng protective gas, to avoid metal dust at high temperature to aoxidize.

Laser curing and sintering processing and close, be only replaced with fluid feed slot by powder hopper, be immersed in Lifting platform in hopper successively declines, and reserves certain thickness liquid state thin layer, laser scanning carrys out curing molding.

From the point of view of Gai Kuoing；Group scan laser selective sintering or curing: it is configured to laser array substantially, Mechanical scan drive, material trough, the lowering or hoisting gear in material trough, electron process part forms；It is divided into sharp Light sintering processing or photocuring mode；The operation principle of its laser sintered mode is: first by the three-dimensional mould of part Type is converted into STL formatted file, then by delamination software, it is carried out layered shaping, i.e. " discretization " process. Before starting processing, first forming room is preheated.Computer i.e. drive circuit is according to the hierarchical model of prototype Controlling the two-dimensional scan track of laser beam, sintering solid dusty material is to form an aspect of part selectively. After powder completes one layer, working piston declines a thickness, and paving powder system spreads new powder. and control laser beam and scan again Sinter new layer. so move in circles, be layering, until 3 d part molding. last, unsintered powder is returned Receive in powder cylinder, and take out profiled member. for laser sintering metallic powder, before sintering, whole workbench It is heated to uniform temperature, the thermal deformation in molding can be reduced, and be beneficial to combination between layers. last, warp After the post processings such as polishing, drying, can complete and meet prototype or the part of demand；And laser curing is with sharp Light sintering processing and close, is only replaced with fluid feed slot by powder hopper, the lifting being immersed in hopper Platform successively declines, and reserves certain thickness liquid state thin layer, laser scanning carrys out curing molding；Either laser burns Knot mode or photocuring mode, all follow group scan method on scan mode, and the core content of this method is specified as: Laser group scan method is that the luminous point using multiple separate lasers constitutes laser spot array (20), forms crowd Many micro scannings region (22)；Synchronization is generated by scan line (21).When the moving range (amplitude) of laser spot, When being respectively equal to the light dot spacing in rows and columns direction, and when the rate of scanning of row is much larger than the rate of scanning situation arranged Under, this is that progressive scan state (is equivalent to the row-field scanning of CRT TV: the rate of scanning of row is higher, hardwood Rate of scanning is relatively low), photoelectricity can cover all regions；Due to group scan mode；If laser array is: MxN, The rate of scanning that will make 2 directions reduces M and N times, and amplitude also reduces M and N times, the machinery of driving Difficulty greatly reduces, galvanometer system become easily some, it might even be possible to directly use mechanical displacement driving Avoiding the galvanometer system of complexity and focus on collecting system, system stability is simple, and due to the quantity of laser instrument For MN, the numerical value of M, N can be that 2-200 is individual or more；Thus the power of single laser instrument is allowed to Decline MN times；Semiconductor laser device, cost and life-span can be chosen further reduce, but it is noted that choosing Take the conforming quality of semiconductor laser device, an advantage is also that the replacing of Laser Devices also becomes to hold Yi Liao；And group scan method has and is divided into: multizone dynamic balancing group scan method and single region group scan method；Multizone moves Balance group scan method is that scanning area is divided into polylith isolated area, and each piece all in that direction that frequency is higher Upper self-movement, and the phase place of motion is reverse, can offset vibration and inertia, it will obtain good dynamic balancing； Single region group scan method: being the entire scan mode of a uniform areas, dynamic balancing can be offset by external devices, To reduce vibration；；Its essential technique feature: use MxN Laser Devices of multiple concurrent working to carry out machine Tool has scanned sintering or solidification work, and its scan amplitude is equal or slightly larger than the point of Laser Devices arrangement square formation Battle array spacing；Its scanning area is divided into multizone dynamic balancing group scan and single region group scan；The driving of mechanical scanning Can be vibration mirror reflected formula, straight line driving, rotation drive-type.

[case study on implementation]

Below in conjunction with accompanying drawing, with regard to preferred embodiment, the invention will be further described:

Fig. 1 laser group scan method schematic diagram.

Fig. 2 group scan laser selective successively sinters 3D shaping machine main body organigram.

Fig. 3 multizone dynamic balancing group scan method schematic diagram.

[accompanying drawing explanation]

(1) laser element

(2) laser beam

(3) laser stent

(4) backswing axis

(5) alternating translational direction

(6) linear electric motors displacement post

(7) linear electric motors

(8) linear electric motors

(9) linear electric motors fixed support

(10) torsion motor rotation axis

(11) torsion motor

(12) torsion motor fixed rack

(13) powder cylinder housing

(14) powder for molding cylinder

(15) feed powder cylinder

(16) powder-laying roller

(20) laser spots during scanning is mobile

(21) scan line

(22) micro scanning region

(23) laser spots

(24) horizontal shift reciprocately value A

(25) vertical shift reciprocately value B

(29) amplitude width

(30) light point area unit

(31) light point area unit

(32) light point area unit

(33) direction of displacement

(34) direction of displacement

(35) direction of displacement

(36) the displacement changing of the relative positions value such as forward

(37) displacement changing of the relative positions value is reversely waited

As shown in Figure 1:

Laser group scan displacement method: the laser spots (23) using multiple separate lasers to be projected lines up battle array Row (being the array of 8x10 in figure), the horizontal spacing of array is A, and the longitudinal pitch of array is B；During scanning Lateral amplitude of vibration approximates horizontal shift reciprocately value A (24), and pitch amplitude approximates vertical shift reciprocately value B (25)； Actual amplitude should be that spacing deducts spot diameter；Constitute the laser spots (20) during scanning is moved, formed numerous (80) micro scanning region (22)；Synchronization is generated by the scan line (21) of each scanning area.

When the light dot spacing of the moving range (amplitude) of laser spot, respectively equal to rows and columns direction, and work as In the case of the rate of scanning of the row rate of scanning much larger than row, this is progressive scan state, and photoelectricity can cover all Region.

As shown in Figure 2:

Group scan laser selective successively sinters the core process device of 3D shaping machine main body structure by feed powder Cylinder (15) and powder for molding cylinder (14) composition, during work (the powder feeding piston) of feed powder cylinder (15) bottom Rise, then by powder-laying roller (16) by powder on powder for molding cylinder (14) surface uniform spreading last layer (upper After once completing sintering, powder for molding cylinder piston (working piston) can fall before the height of 1 layer in advance, for next Paving powder slot milling).

The group scan of laser beam is: by the linear electric motors (7) being fixed on linear electric motors fixed support (9) And (8) make laser stent (3) along level (X) side by flexible linear electric motors displacement post (6) To shift reciprocately；So laser element (1) the array also general being fixed together with laser stent (3) Therewith along level (X) direction shift reciprocately；Additionally torsion motor fixed rack (12) is rigidly fixed in one The torsion motor rotation axis (10) of the torsion motor (11) risen is and linear electric motors fixed support (9) rigidity Connect, along with swashing that rotation and the laser stent (3) of torsion motor rotation axis (10) are fixed together Light device unit (1) array also will be therewith around Y-axis: backswing axis (4) rotates；So laser element (1) Array will simultaneously participate in 2 kinds of compound motions, and the focus point of each laser beam (2) will complete group scan and move Make.(5) being the alternating translational direction of linear electric motors fixed support (9), (13) are 2 powder cylinder housings.

Other main working process of its complete machine are: first, the threedimensional model of part is converted into STL form File, then carries out layered shaping, i.e. " discretization " process by delamination software to it.Before starting processing, First forming room is preheated.Computer i.e. drive circuit controls the two dimension of laser beam according to the hierarchical model of prototype Scanning track, sintering solid dusty material is to form an aspect of part selectively. after powder completes one layer, Working piston declines a thickness, and paving powder system spreads new powder. and control laser beam and scan the new layer of sintering again. so follow Ring is reciprocal, is layering, until 3 d part molding. and last, by unsintered Powder Recovery to powder cylinder, and Take out profiled member. for laser sintering metallic powder, before sintering, whole workbench is heated to uniform temperature, The thermal deformation in molding can be reduced, and be beneficial to combination between layers. last, locate after polishing, drying etc. After reason, can complete and meet prototype or the part of demand.

As shown in Figure 3:

Scanning array is divided into 3 regions, respectively: light point area unit (30), light point area unit (31), Not luminous point territory element (32)；Arrange assembly quality so that the quality approximation etc. of light point area unit (31) In light point area unit (30) and light point area unit (32) sum.

When displacements changing of the relative positions value (36) such as the forward making light point area unit (31) are approximately equal to light point area Unit (30) and when reversely waiting displacement changing of the relative positions value (37) of light point area unit (32), and position phase (fortune Dynamic direction) contrary time, translation inertia cancels out each other, and dynamic balancing is best.(29) it is amplitude width.

Claims

1. group scan laser selective sintering or curing: it is configured to laser array, mechanical scanning substantially Driving means, material trough, the lowering or hoisting gear in material trough, electron process part forms；It is divided into laser sintered side Formula or photocuring mode；The operation principle of its laser sintered mode is: be first converted into by the threedimensional model of part STL formatted file, then carries out layered shaping, i.e. " discretization " process by delamination software to it.Starting Before processing, first forming room is preheated.Computer i.e. drive circuit controls to swash according to the hierarchical model of prototype The two-dimensional scan track of light beam, sintering solid dusty material is to form an aspect of part selectively. powder After completing one layer, working piston declines a thickness, and paving powder system spreads new powder. and control laser beam and scan sintering again New layer. so move in circles, be layering, until 3 d part molding. last, unsintered Powder Recovery is arrived In powder cylinder, and take out profiled member. for laser sintering metallic powder, before sintering, whole workbench is added Heat, to uniform temperature, can reduce the thermal deformation in molding, and be beneficial to combination between layers. and last, economy-combat After the post processings such as mill, drying, can complete and meet prototype or the part of demand；And laser curing and laser Sintering processing and close, is only replaced with fluid feed slot by powder hopper, the lifting platform being immersed in hopper Successively decline, reserve certain thickness liquid state thin layer, laser scanning carry out curing molding；The most laser sintered Mode or photocuring mode, all follow group scan method on scan mode, and the core content of this method is specified as: swashs Light group scan method is that the luminous point using multiple separate lasers constitutes laser spot array (20), is formed numerous Micro scanning region (22)；Synchronization is generated by scan line (21).When the moving range (amplitude) of laser spot, When being respectively equal to the light dot spacing in rows and columns direction, and when the rate of scanning of row is much larger than the rate of scanning situation arranged Under, this is that progressive scan state (is equivalent to the row-field scanning of CRT TV: the rate of scanning of row is higher, hardwood Rate of scanning is relatively low), photoelectricity can cover all regions；Due to group scan mode；If laser array is: MxN, The rate of scanning that will make 2 directions reduces M and N times, and amplitude also reduces M and N times, the machinery of driving Difficulty greatly reduces, galvanometer system become easily some, it might even be possible to directly use mechanical displacement driving Avoiding the galvanometer system of complexity and focus on collecting system, system stability is simple, and due to the quantity of laser instrument For MN, the numerical value of M, N can be that 2-200 is individual or more；Thus the power of single laser instrument is allowed to Decline MN times；Semiconductor laser device, cost and life-span can be chosen further reduce, but it is noted that choosing Take the conforming quality of semiconductor laser device, an advantage is also that the replacing of Laser Devices also becomes to hold Yi Liao；And group scan method has and is divided into: multizone dynamic balancing group scan method and single region group scan method；Multizone moves Balance group scan method is that scanning area is divided into polylith isolated area, and each piece all in that direction that frequency is higher Upper self-movement, and the phase place of motion is reverse, can offset vibration and inertia, it will obtain good dynamic balancing； Single region group scan method: being the entire scan mode of a uniform areas, dynamic balancing can be offset by external devices, To reduce vibration；Scanning machinery realize can pass through, rotating shaft reciprocating rotation mode, linear vibration mode, Vibration mirror reflected mode.The most that mode, owing to amplitude is the least, does not haves laser beam focus plane mistake Big deviation liquid level or the powder planar environment of powder groove；Its feature is that the MxN using multiple concurrent workings Individual Laser Devices carry out mechanical scanning and complete sintering or solidification work, and its scan amplitude is equal or slightly larger than laser The lattice distance of device arrangement square formation；Its scanning area is divided into multizone dynamic balancing group scan and single region group to sweep Retouch；The driving of mechanical scanning can be vibration mirror reflected formula, straight line driving, rotation drive-type.

2. group scan laser selective sintering or curing formation machine: it is configured to laser array substantially, and machinery is swept Retouching driving means, material trough, the lowering or hoisting gear in material trough, electron process part forms；It is divided into laser sintered Mode or photocuring mode；The operation principle of its laser sintered mode is ibid；Its feature is that this group In laser scanning structure in scanning laser selective sintering or curing formation machine, employ the choosing of group scan laser Selecting property is laser sintered or curing.