CN104732028A - Method for generating powder laying and sintering supporting structure of aircraft structural part based on space lattice - Google Patents

Abstract

The invention relates to a method for generating a powder laying and sintering supporting structure of an aircraft structural part based on a space lattice. The method comprises the steps of firstly calculating a bounding box of the supporting structure; secondly calculating the node position in the supporting structure within the range of the bounding box; then judging the necessity of generating a supporting rod according to the characteristics of the part and the node position; finally generating an entity according to the supporting rod and a sketch input by a user, and designing a rounded corner or a fillet in the supporting structure. The method has the advantages of being high in efficiency and wide in using range, aiming at a material adding manufacturing mode of powder laying and sintering, the method can be used for fast generation of the supporting structure of a part in any shape, and the method has a good application prospect.

Description

A kind of paving of the aircraft structure based on space lattice powder sintering supporting construction generation method

Technical field

The present invention relates to the generation method of supporting construction in the manufacture of aircraft structure paving powder sintering.Adopt the method can generate the cad model of supporting construction fast, thus be hardware paving powder sintering manufacture provide the structural support rapid design tools, belong to hardware and increase material manufacturing technology field.

Background technology

At present, the increasing material manufacture of hardware paving powder sintering has obtained propagation and employment widely, and at Field of Aviation Manufacturing, this technology has been used in the development of shaped piece, complex pipes etc.In the sintering process of hardware, need to design suitable supporting construction for the process characteristic of part, and sinter supporting construction in the process of sintered part(s) simultaneously, thus stability and the accuracy of design of part can be kept, and the heat absorbed rapidly in sintering is formed in part, prevent part from producing larger thermal deformation etc.

In order to reach the effect of dimension shape, supporting construction must possess enough intensity; Because the price of metal powder is higher, what need control supporting construction uses powder amount.In addition, also need to ensure that supporting construction can be removed from part easily.Based on the demand, supporting construction is generally designed to comparatively complicated space structure, according to artificial modeling, not only expend time in, and difficulty is very large.

Summary of the invention

In order to solve the technical matters of above-mentioned existence, the invention provides the rapid generation of supporting construction in a kind of hardware paving powder sintering manufacture process, the method creatively proposes the supporting construction generation technique based on space lattice, efficiently solve that supporting construction bounding box generates, space layouts, support bar design and the critical problem such as supporting construction solid generation, increasing manufacture process research of hardware is had very important significance.

The object of the invention is to be achieved through the following technical solutions: a kind of paving of the aircraft structure based on space lattice powder sintering supporting construction method of generationing, the main-process stream that the method realizes is: 1) part model loading; 2) user interactions input parameters of braced structure; 3) bounding box of supporting construction is calculated; 4) in supporting construction general profile, arrange the support dot matrix of supporting construction; 5) orientation of support bar in dot matrix is calculated; 6) entity of supporting construction is created.

Described step 2) user interactions input parameters of braced structure, comprise (2.1) and select part to need to add the manifold supported in sintering process; (2.2) the termination plane of supporting construction is selected; (2.3) Cutter coordinate system of part is selected; (2.4) cross-sectional shape of supporting construction is selected, and the dimensional parameters of input section; (2.5) the length l of support bar is inputted; (2.6) the angle θ between support bar and processing platform is inputted; (2.7) the radius of corner r in supporting construction is inputted ₂or chamfer dimesion c.

Described (2.4) select the cross-sectional shape of supporting construction, and the dimensional parameters of input section, namely user can select cross sectional shape to be round, and inputs radius of a circle r ₁; Or select cross sectional shape to be rectangle, and input the long h of rectangle and wide v; Or select cross sectional shape to be any regular polygon, and input the diameter d of regular polygon circumscribed circle.

Described step 3) calculate the bounding box of supporting construction, comprise following content: (3.1) generate the face profile of supporting construction on processing base station; (3.2) bounding box of supporting construction is solved; (3.3) size of bounding box on each direction of principal axis of coordinate system is solved.Wherein:

Described (3.1) generate the face profile of supporting construction on processing base station, and concrete grammar is:

1. the ordered set of user-selected part bottom surface is obtained g is made to be empty set;

2. F is obtained _bthe quantity n of middle element, if n<1, then exits, returns failure; If n=1, then turn 4.; If n>1, then turn 3.;

3. for F _bin each element carry out packet transaction, concrete grammar is:

The first step: make i=0, k=0, makes G _kfor empty set;

Second step: get F _bin first element will be added into G _k, and from F _bmiddle deletion

3rd step: right j=s+1 ..., n, if with there is common edge, then will be added into G _kin, and from F _bmiddle deletion

4th step: by G _kbe added into G;

5th step: make k=k+1;

6th step: judge F _bwhether be empty, if not empty, then turn second step; Otherwise turn 5.;

4. G is made ₀for empty set, will be added into G ₀, by G ₀be added into G;

5. for obtain its Boundary Loop collection, concrete grammar is:

The first step: obtain G _jthe number m of middle element, if m=1, then turns second step; Otherwise to G _jbe handled as follows:

First, G is extracted _jin all face for extract the limit on the outer shroud of f, form limit collection E _k{ e ₁, e ₂..., e _n, make E=E ₁∪ E ₂∪ ... ∪ E _t, if e is G _jin the common edge of two elements, then from E, delete e.

Then, make L be empty set, get e ∈ E, make L={e}, e is deleted from E, if e ' has public vertex with e, then e ' is added into L, and e ' is deleted from E.

Finally, according to the method described above element in E is divided into n ring, namely has E=L ₁∪ L ₂∪ ... ∪ L _n, and L _i∩ L _jfor empty set, i, j=1,2 ..., n.

Second step: obtain G ₁in face f ₁, obtain f ₁outer shroud L _out, then L _outbe outer boundary ring collection;

3rd step: for G _jin all, get all inner ring in each face, it joined respectively inner boundary ring collection L _in;

4th step: make L _boundary=L _out∪ L _in;

5th step: for L _boundaryin each element l _i, get l _iin each limit e ₁, e ₂..., e _n, the termination plane respectively to supporting construction is projection p ₁, p ₂..., p _n;

6th step: detect p ₁, p ₂..., p _nwhether can form closed-loop, if closed ring cannot be projected out, then carry out stitching process; Concrete processing procedure is:

First, for i=1,2 ..., n-1, calculates p _isummit with p _i+1summit between distance d ₁, d ₂, d ₃, d ₄, calculate d ₁~ d ₄between minimum value d _minif, d _min≤ ε, then without the need to carrying out stitching process;

Secondly, if d _min> ε, solves p and p _i+1between intersection point, if both exist intersection point, then replace p and p respectively with this intersection point _i+1the point that middle distance intersection point is nearer, if both do not exist intersection point, then at p and p _i+1in adjacent nearest point-to-point transmission make straight-line segment l, and will to be added in ring.

Finally, according to the method described above, to p ₁, p ₂..., p _nin adjacent between two projection do to sew up process.

Described (3.2) solve the bounding box of supporting construction, and detailed process is: with the face profile of trying to achieve in (1) for sketch, with the outgoing of profile place plane arrow n for draw direction makes stretch characteristic.Wherein, the computing method of the outer direction of normal of profile place plane are:

First, get above-mentioned steps 2) in any vertex v in user selects in (2.2) sub-step manifold _e, any vertex v of making even in facial contour _s, and do by v _spoint to v _evector v _s,e, make r=nv _s,eif r>0, then the outer direction of normal of profile is n, otherwise is-n.

Then, with above-mentioned steps 2) in user selects in (2.2) sub-step manifold for shearing element, above-mentioned stretch characteristic is reduced.

Described (3.3) namely solve the size d of bounding box on each direction of principal axis of coordinate system _x, d _ywith d _z.

Described step 4) arrange in supporting construction bounding box and the support dot matrix of supporting construction comprise following content: the projector distance in (4.1) computer memory dot matrix between each point; (4.2) the computer memory dot matrix quantity of layouting on each direction of principal axis of coordinate system; (4.3) coordinate figure of each point in space lattice is determined; (4.4) position relationship between each point and supporting construction bounding box in space lattice is judged; Wherein:

Projector distance in described (4.1) computer memory dot matrix between each point, concrete grammar is for by step 2) in the projected length of Size calculation support bar in each direction of principal axis of coordinate system that input of sub-step (2.5), (2.6), computing formula is:

l _z＝l·sinθ。

In space lattice, each point is respectively l in the spacing in x, y, z direction _x, l _y, l _z.

The quantity that described (4.2) computer memory dot matrix is layouted on each direction of principal axis of coordinate system, specific formula for calculation is:

n _y＝|d _y/l _y|，

Described (4.3) determine the coordinate figure of each point in space lattice, and concrete grammar is:

First, according to the difference of the Z coordinate figure of each point in dot matrix, point is divided into n _z+ 2 layers, wherein, the point be positioned in coordinate system XOY plane is designated as the 1st layer.

Secondly, right if i is odd number, then remembering i-th layer in dot matrix is Primary layer; If i is even number, then remembering i-th layer in dot matrix is middle layer.

Finally, (n is arranged in the Primary layer in dot matrix _x+ 2) (n _y+ 2) individual point, if certain Primary layer be numbered k ₁, in this layer, the point that agreement x-axis coordinate figure is identical forms a line, and the some formation one that y-axis coordinate figure is identical arranges, then the i-th row, and the coordinate of jth row point is:

$\left\{\begin{array}{c}x=l_x\&CenterDot;(i-1),i\&Element;\{\mathrm{1,2},...,n_x+2\};\\ y=l_y\&CenterDot;(j-1),j\&Element;\{\mathrm{1,2},...,n_y+2\};\\ z=l_z\&CenterDot;(k_1-1),k_1\&Element;\{\mathrm{1,3},...,n_z+2\}.\end{array}\right.$

(n is arranged in the middle layer of dot matrix _x+ 1) (n _y+ 1) individual point, if certain middle layer be numbered k ₂, in this layer, the point that agreement x-axis coordinate figure is identical forms a line, and the some formation one that y-axis coordinate figure is identical arranges, then the i-th row, and the coordinate of jth row point is:

$\left\{\begin{array}{c}x=l_x\&CenterDot;(i-0.5),i\&Element;\{\mathrm{1,2},...,n_x+1\};\\ y=l_y\&CenterDot;(j-0.5),j\&Element;\{\mathrm{1,2},...,n_y+1\};\\ z=l_z\&CenterDot;(k_2-0.5),k_2\&Element;\{2,4,...,n_z+2\}.\end{array}\right.$

Described (4.4) judge the position relationship in space lattice between each point and supporting construction bounding box, concrete grammar is: for each point in space lattice, judge whether it is arranged in the bounding box of supporting construction, if point is arranged in entity bounding box, it is true for then marking current point, otherwise mark current point is false.

Described step 5) calculate the orientation of support bar in dot matrix, comprise following content: (5.1) determine the endpoint number of each support bar; (5.2) support bar is created; Wherein:

Described (5.1) determine the endpoint number of each support bar, and concrete grammar is:

For any point in middle layer, calculate another endpoint number of this some place support bar.Concrete grammar is: establish the layer at the some place in middle layer to be numbered k, and the row, column numbering at its place is respectively i, j, then there are at most 8 support bars at this some place, and the row, column of another end points of these 8 support bars, the numbering at layer place are as shown in the table respectively;

Support bar sequence number

1

2

3

4

5

6

7

8

End points line number

i

i+1

i+1

i

i

i+1

i+1

i

End points column number

j

j

j+1

j+1

j

j

j+1

j+1

Endpoint layer is numbered

k-1

k-1

k-1

k-1

k+1

k+1

k+1

k+1

Described (5.2), for creating support bar, concrete grammar is:

1., in the process creating supporting construction, be successively create support bar according to middle layer numbering order from small to large; In each middle layer, be create support bar line by line from small to large according to the line number of point; In each row, be create support bar one by one from small to large according to the column number of point;

2. create support bar to each point in middle layer, concrete steps are as follows:

The first step: judge the sequence number that is adjacent be 1 ~ 4 Primary layer end points whether possess support bar, if the layer of the end points of Primary layer is numbered 1, then think that these end points possess support bar.If four Primary layer end points all do not possess support bar, then do not create support bar at this some place; Otherwise turn second step.

Second step: be four Primary layer end points of 1 ~ 4 for sequence number, if end points possesses support bar, then judge between current point and Primary layer end points, to meet the condition creating support bar, if can satisfy condition, create support bar, and record this Primary layer end points and possess support bar; Otherwise do not create support bar.

3rd step: if the middle layer end points in second step and all dissatisfied condition creating support bar between four Primary layer end points, then terminate; Otherwise, judge sequence number be 5 ~ 8 four Primary layer end points whether meet the condition creating support bar, if meet, then create support bar, and record this Primary layer end points and possess support bar; Otherwise do not create support bar.

In above-mentioned second step and the 3rd step, the condition creating support bar between middle layer and Primary layer end points is determined by following rule:

Rule 1: if middle layer and Primary layer end points are all outside at supporting construction bounding box, then do not create support bar;

Rule 2: if middle layer and Primary layer end points are all inner at supporting construction bounding box or on bounding box border, then create support bar;

Rule 3: if be a bit positioned at supporting construction bounding box outside in middle layer and Primary layer end points, be not positioned at supporting construction bounding box outside, line between then doing at 2, judge this line and need to add between the manifold that supports whether there is intersection point, if there is intersection point, then create support bar, otherwise do not create support bar.

Described step 6) for creating the entity of supporting construction, comprise following content: (6.1) merge support bar; (6.2) supporting construction entity is created; (6.3) supplementing structure of supporting construction is created; (6.4) chamfering or the fillet of supporting construction is created; Wherein:

Described (6.1), for merging support bar, concrete grammar is:

1. solve the direction of each support bar, the direction of each support bar points to Primary layer end points by middle layer end points;

2. for all support bars, if direction is parallel, then by its point extremely same group, so, all support bars can be divided into four groups;

3. carry out merging treatment for each group support bar, concrete steps are:

The first step: create an empty chained list;

Second step: for arbitrary support bar, if current chained list is empty, is then added in chained list by support bar; Otherwise, judge each support bar in chained list can with its merging; In this step, judge that the rule that can two support bars merge is: if the middle layer endpoint number at two support bar places or Primary layer endpoint number identical, then two support bars can merge;

3rd step: if when front support rod can merge with the support bar of 1 in chained list, then change the endpoint number of support bar in chained list; If when front support rod can merge with the support bar of 2 in chained list, then using the endpoint number of the endpoint number after merging as support bar in chained list, and the support bar of redundancy in chained list is deleted.

Described (6.2) are for creating supporting construction entity, concrete grammar is: for each chained list in (6.1), obtain each support bar element in chained list respectively, with the arbitrary end points of support bar for Plane-point, with support bar direction for sketch plane made by planar process arrow; With the cross sectional shape of user's input for sketch, with support bar direction for draw direction makes stretch characteristic;

Described (6.3) are the supplementing structure creating supporting construction, and concrete grammar is: for each point in middle layer, if the support bar number at this place is greater than 0 and is less than 8, then create supplementing structure at this place, concrete creation method is:

If 1. user input cross sectional shape be circle, then with this point for the centre of sphere, the radius being ball with the section radius inputted makes entity ball;

If 2. user input cross sectional shape be rectangle, then with this point for the centre of sphere, with for radius makes entity ball;

If 3. user input cross sectional shape be regular polygon, then with this point for the centre of sphere, with regular polygon circumradius for radius makes entity ball;

Described (6.4) are the chamfering or the fillet that create supporting construction, concrete grammar is: according to step 2) in input chamfer radius or radius of corner, first sharp edges all in supporting construction is obtained, then the position of sharp edge is judged, adjacent sharp edge is returned to one group, often will organize sharp edge as an operand, carry out chamfering or fillet operation.In this step, judge that whether limit in part is that the method for sharp edge is as follows:

1. two manifold when place, front are obtained;

2. obtain when parameter mid point in front;

3. obtain the outer method pointed out in parameter in two faces respectively to vow;

If 4. two outer methods are vowed not parallel, then this limit is sharp edge, otherwise this limit is not sharp edge.

Beneficial effect of the present invention: the present invention is Aircraft-Oriented structural member paving powder sintering technique, a kind of supporting construction generation method based on space lattice proposed, have that formation speed is fast, structure type is many, the advantages such as usable range is wide, for the increasing material manufacture of paving powder sintering, the supporting construction that can be used for arbitrary shape part generates fast, is applicable to the sintering of various design of part, has filled up domestic blank in this area.Have a good application prospect.

Accompanying drawing explanation

Fig. 1 is the process flow diagram of aircraft structure paving powder sintering supporting construction generating algorithm.

Fig. 2 is each geometric object schematic diagram needing user interactions to choose in this method.

Fig. 3 (a) to Fig. 3 (c) is the supporting construction cross sectional shape that needs user interactions to input in this method and scale diagrams.

Fig. 4 needs to add the perspective view of manifold on supporting construction terminal surface supported.

Fig. 5 is the formation zone of supporting construction and the bounding box schematic diagram in Cutter coordinate system thereof.

Fig. 6 is the space lattice schematic diagram of supporting construction.

Fig. 7 is each support bar schematic diagram in supporting construction.

Fig. 8 is the solid model schematic diagram of supporting construction and part.

Fig. 9 is the fillet schematic diagram in supporting construction.

Embodiment

Below in conjunction with accompanying drawing, embodiment of the present invention is described in detail.This embodiment carries out under premised on invention technical scheme, there is shown herein detailed embodiment and concrete implementation procedure, but protection scope of the present invention is not limited to following embodiment.

Figure 1 shows that the specific implementation flow process of the supporting construction generation method that the present invention proposes, implementation step is: the main-process stream that 1) the method realizes is: 1) part model is loaded into; 2) user interactions input parameters of braced structure; 3) bounding box of supporting construction is calculated; 4) in supporting construction general profile, arrange the support dot matrix of supporting construction; 5) orientation of support bar in dot matrix is calculated; 6) entity of supporting construction is created; Wherein:

Step 1): part model is loaded into, and is namely loaded into part model in existing CAD/CAM system;

Step 2): user interactions input parameters of braced structure, comprises following content: (2.1) select part to need to add the manifold supported in sintering process; (2.2) the termination plane of supporting construction is selected; (2.3) Cutter coordinate system of part is selected; (2.4) cross-sectional shape of supporting construction is selected, and the dimensional parameters of input section; (2.5) the length l of support bar is inputted; (2.6) the angle θ between support bar and processing platform is inputted; (2.7) the radius of corner r in supporting construction is inputted ₂or chamfer dimesion c.Figure 2 shows that certain part case needs the geometric object of specifying alternately when generating supporting construction;

Described (2.4) select the cross-sectional shape of supporting construction, and the dimensional parameters of input section, namely user can select cross sectional shape to be round, and inputs radius of a circle r ₁, as shown in Fig. 3 (a); Or select cross sectional shape to be rectangle, and input the long h of rectangle and wide v, as shown in Fig. 3 (b); Or select cross sectional shape to be any regular polygon, and input the diameter d of regular polygon circumscribed circle, as shown in Fig. 3 (c).

Step 3): the formation zone solving supporting construction, comprises following content: (3.1) generate the face profile of supporting construction on terminal surface; (3.2) formation zone and the bounding box thereof of supporting construction is solved; (3.3) size of bounding box on each direction of principal axis of coordinate system is solved.Wherein:

Described (3.1) generate the face profile of supporting construction on processing base station, are illustrated in figure 4 in part the projected outline of manifold on supporting construction terminal surface needing to add supporting construction;

Described (3.2) solve the bounding box of supporting construction, are illustrated in figure 5 the supporting construction formation zone of certain part and the bounding box in Cutter coordinate system thereof;

Step 4): the support dot matrix arranging supporting construction in supporting construction bounding box, comprises following content: the projector distance in (4.1) computer memory dot matrix between each point; (4.2) the computer memory dot matrix quantity of layouting on each direction of principal axis of coordinate system; (4.3) coordinate figure of each point in space lattice is determined; (4.4) position relationship between each point and supporting construction bounding box in space lattice is judged; Wherein:

Projector distance in described (4.1) computer memory dot matrix between each point, concrete grammar is for by step 2) in the projected length of Size calculation support bar in each direction of principal axis of coordinate system that input of sub-step (2.5), (2.6), computing formula is:

$l_x=l\&CenterDot;\cos \mathrm{\&theta;}/\sqrt{2},l_y=l\&CenterDot;\cos \mathrm{\&theta;}/\sqrt{2},$ l _z＝l·sinθ。

In space lattice, each point is respectively l in the spacing in x, y, z direction _x, l _y, l _z.

The quantity that described (4.2) computer memory dot matrix is layouted on each direction of principal axis of coordinate system, specific formula for calculation is:

n _y＝|d _y/l _y|，

Described (4.3) determine the coordinate figure of each point in space lattice, and concrete grammar is:

First, according to the difference of the Z coordinate figure of each point in dot matrix, point is divided into n _z+ 2 layers, wherein, the point be positioned in coordinate system XOY plane is designated as the 1st layer.

Secondly, right if i is odd number, then remembering i-th layer in dot matrix is Primary layer; If i is even number, then remembering i-th layer in dot matrix is middle layer.

Finally, (n is arranged in the Primary layer in dot matrix _x+ 2) (n _y+ 2) individual point, if certain Primary layer be numbered k ₁, in this layer, the point that agreement x-axis coordinate figure is identical forms a line, and the some formation one that y-axis coordinate figure is identical arranges, then the i-th row, and the coordinate of jth row point is:

$\left\{\begin{array}{c}x=l_x\&CenterDot;(i-1),i\&Element;\{\mathrm{1,2},...,n_x+2\};\\ y=l_y\&CenterDot;(j-1),j\&Element;\{\mathrm{1,2},...,n_y+2\};\\ z=l_z\&CenterDot;(k_1-1),k_1\&Element;\{\mathrm{1,3},...,n_z+2\}.\end{array}\right.$

(n is arranged in the middle layer of dot matrix _x+ 1) (n _y+ 1) individual point, if certain middle layer be numbered k ₂, in this layer, the point that agreement x-axis coordinate figure is identical forms a line, and the some formation one that y-axis coordinate figure is identical arranges, then the i-th row, and the coordinate of jth row point is:

$\left\{\begin{array}{c}x=l_x\&CenterDot;(i-0.5),i\&Element;\{\mathrm{1,2},...,n_x+1\};\\ y=l_y\&CenterDot;(j-0.5),j\&Element;\{\mathrm{1,2},...,n_y+1\};\\ z=l_z\&CenterDot;(k_2-0.5),k_2\&Element;\{2,4,...,n_z+2\}.\end{array}\right.$

Described (4.4) judge the position relationship in space lattice between each point and supporting construction formation zone, concrete grammar is: for each point in space lattice, judges whether it is arranged in supporting construction formation zone, if, it is true for then marking current point, otherwise mark current point is false.

Figure 6 shows that each point being arranged in supporting construction formation zone.

Described step 5) calculate the orientation of support bar in dot matrix, comprise following content: (5.1) determine the endpoint number of each support bar; (5.2) support bar is created; Wherein:

Described (5.1) determine the endpoint number of each support bar, and concrete grammar is:

For any point in middle layer, calculate another endpoint number of this some place support bar.Concrete grammar is: establish the layer at the some place in middle layer to be numbered k, and the row, column numbering at its place is respectively i, j, then there are at most 8 support bars at this some place, and the row, column of another end points of these 8 support bars, the numbering at layer place are as shown in table 1 respectively.

Support bar sequence number

1

2

3

4

5

6

7

8

End points line number

i

i+1

i+1

i

i

i+1

i+1

i

End points column number

j

j

j+1

j+1

j

j

j+1

j+1

Endpoint layer is numbered

k-1

k-1

k-1

k-1

k+1

k+1

k+1

k+1

Described (5.2), for creating support bar, concrete grammar is:

1., in the process creating supporting construction, be successively create support bar according to middle layer numbering order from small to large; In each middle layer, be create support bar line by line from small to large according to the line number of point; In each row, be create support bar one by one from small to large according to the column number of point;

2. create support bar to each point in middle layer, concrete steps are as follows:

The first step: judge the sequence number that is adjacent be 1 ~ 4 Primary layer end points whether possess support bar, if the layer of the end points of Primary layer is numbered 1, then think that these end points possess support bar.If four Primary layer end points all do not possess support bar, then do not create support bar at this some place; Otherwise turn second step.

Second step: be four Primary layer end points of 1 ~ 4 for sequence number, if end points possesses support bar, then judge between current point and Primary layer end points, to meet the condition creating support bar, if can satisfy condition, create support bar, and record this Primary layer end points and possess support bar; Otherwise do not create support bar.

3rd step: if the middle layer end points in second step and all dissatisfied condition creating support bar between four Primary layer end points, then terminate; Otherwise, judge sequence number be 5 ~ 8 four Primary layer end points whether meet the condition creating support bar, if meet, then create support bar, and record this Primary layer end points and possess support bar; Otherwise do not create support bar.

In above-mentioned second step and the 3rd step, the condition creating support bar between middle layer and Primary layer end points is determined by following rule:

Rule 1: if middle layer and Primary layer end points are all outside at supporting construction bounding box, then do not create support bar;

Rule 2: if middle layer and Primary layer end points are all inner at supporting construction bounding box or on bounding box border, then create support bar;

Rule 3: if be a bit positioned at supporting construction bounding box outside in middle layer and Primary layer end points, be not positioned at supporting construction bounding box outside, line between then doing at 2, judge this line and need to add between the manifold that supports whether there is intersection point, if there is intersection point, then create support bar, otherwise do not create support bar.

Figure 7 shows that the support bar in the supporting construction of certain part case.

Described step 6) for creating the entity of supporting construction, comprise following content: (6.1) merge support bar; (6.2) supporting construction entity is created; (6.3) supplementing structure of supporting construction is created; (6.4) chamfering or the fillet of supporting construction is created; Wherein:

Described (6.1), for merging support bar, concrete grammar is:

1. solve the direction of each support bar, the direction of each support bar points to Primary layer end points by middle layer end points;

2. for all support bars, if direction is parallel, then by its point extremely same group, so, all support bars can be divided into four groups;

3. carry out merging treatment for each group support bar, concrete steps are:

The first step: create an empty chained list;

Second step: for arbitrary support bar, if current chained list is empty, is then added in chained list by support bar; Otherwise, judge each support bar in chained list can with its merging; In this step, judge that the rule that can two support bars merge is: if the middle layer endpoint number at two support bar places or Primary layer endpoint number identical, then two support bars can merge;

3rd step: if when front support rod can merge with the support bar of 1 in chained list, then change the endpoint number of support bar in chained list; If when front support rod can merge with the support bar of 2 in chained list, then using the endpoint number of the endpoint number after merging as support bar in chained list, and the support bar of redundancy in chained list is deleted.

Described (6.2) are for creating supporting construction entity, concrete grammar is: for each chained list in (1), obtain each support bar element in chained list respectively, with the arbitrary end points of support bar for Plane-point, with support bar direction for sketch plane made by planar process arrow; With the cross sectional shape of user's input for sketch, with support bar direction for draw direction makes stretch characteristic;

Described (6.3) are the supplementing structure creating supporting construction, and concrete grammar is: for each point in middle layer, if the support bar number at this place is greater than 0 and is less than 8, then create supplementing structure at this place, concrete creation method is:

If 1. user input cross sectional shape be circle, then with this point for the centre of sphere, the radius being ball with the section radius inputted makes entity ball;

If 2. user input cross sectional shape be rectangle, then with this point for the centre of sphere, with for radius makes entity ball;

If 3. user input cross sectional shape be regular polygon, then with this point for the centre of sphere, with regular polygon circumradius for radius makes entity ball;

Figure 8 shows that the supporting construction of certain part case.

Described (6.4) are the chamfering or the fillet that create supporting construction, concrete grammar is: according to step 2) in input chamfer radius or radius of corner, first sharp edges all in supporting construction is obtained, then the position of sharp edge is judged, adjacent sharp edge is returned to one group, often will organize sharp edge as an operand, carry out chamfering or fillet operation.In this step, judge that whether limit in part is that the method for sharp edge is as follows:

1. two manifold when place, front are obtained;

2. obtain when parameter mid point in front;

3. obtain the outer method pointed out in parameter in two faces respectively to vow;

If 4. two outer methods are vowed not parallel, then this limit is sharp edge, otherwise this limit is not sharp edge.

Figure 9 shows that the fillet in certain part case supporting construction.

Claims (5)

1. the paving of the aircraft structure based on a space lattice powder sintering supporting construction generation method, is characterized in that: the concrete steps of the method are as follows:

1) part model is loaded into;

2) user interactions input parameters of braced structure: specifically comprise

(2.1) part is selected to need to add the manifold supported in sintering process;

(2.2) the termination plane of supporting construction is selected;

(2.3) Cutter coordinate system of part is selected;

(2.4) cross-sectional shape of supporting construction is selected, and the dimensional parameters of input section:

If 1. cross sectional shape is circle, then input radius of a circle r ₁;

If 2. cross sectional shape is rectangle, then input the long h of rectangle and wide v;

If 3. cross sectional shape is any regular polygon, then input the diameter d of regular polygon circumscribed circle;

(2.5) the length l of support bar is inputted;

(2.6) the angle θ between support bar and processing platform is inputted;

(2.7) the radius of corner r in supporting construction is inputted ₂or chamfer dimesion c;

3) bounding box of supporting construction is calculated; Comprise following content:

(3.1) face profile of supporting construction on processing base station is generated;

(3.2) bounding box of supporting construction is solved;

(3.3) size of bounding box on each direction of principal axis of coordinate system is solved;

4) in supporting construction general profile, arrange the space lattice of supporting construction; Comprise following content:

(4.1) projector distance in computer memory dot matrix between each point;

(4.2) the computer memory dot matrix quantity of layouting on each direction of principal axis of coordinate system;

(4.3) coordinate figure of each point in space lattice is determined;

(4.4) position relationship between each point and supporting construction bounding box in space lattice is judged;

5) orientation of support bar in dot matrix is calculated; Comprise following content:

(5.1) endpoint number of each support bar is determined;

(5.2) support bar is created;

6) entity of supporting construction is created; Comprise following content:

(6.1) support bar is merged;

(6.2) supporting construction entity is created;

(6.3) supplementing structure of supporting construction is created;

(6.4) chamfering or the fillet of supporting construction is created.

2. a kind of paving of the aircraft structure based on space lattice powder sintering supporting construction generation method according to claim 1, is characterized in that: described (3.1) generate the face profile of supporting construction on processing base station, and concrete grammar is:

1. the ordered set of user-selected part bottom surface is obtained g is made to be empty set;

2. F is obtained _bthe quantity n of middle element, if n<1, then exits, returns failure; If n=1, then turn 4.; If n>1, then turn 3.;

3. for F _bin each element carry out packet transaction, concrete grammar is:

The first step: make i=0, k=0, makes G _kfor empty set;

Second step: get F _bin first element will be added into G _k, and from F _bmiddle deletion

3rd step: right j=s+1 ..., n, if with there is common edge, then will be added into G _kin, and from F _bmiddle deletion

4th step: by G _kbe added into G;

5th step: make k=k+1;

6th step: judge F _bwhether be empty, if not empty, then turn second step; Otherwise turn 5.;

4. G is made ₀for empty set, will be added into G ₀, by G ₀be added into G;

5. for obtain its Boundary Loop collection, concrete grammar is:

The first step: obtain G _jthe number m of middle element, if m=1, then turns second step; Otherwise to G _jbe handled as follows:

First, G is extracted _jin all face for extract the limit on the outer shroud of f, form limit collection E _k{ e ₁, e ₂..., e _n, make E=E ₁∪ E ₂∪ ... ∪ E _t, if e is G _jin the common edge of two elements, then from E, delete e;

Then, make L be empty set, get e ∈ E, make L={e}, e is deleted from E, if e ' has public vertex with e, then e ' is added into L, and e ' is deleted from E;

Finally, according to the method described above element in E is divided into n ring, namely has E=L ₁∪ L ₂∪ ... ∪ L _n, and L _i∩ L _jfor empty set, i, j=1,2 ..., n;

Second step: obtain G ₁in face f ₁, obtain f ₁outer shroud L _out, then L _outbe outer boundary ring collection;

3rd step: for G _jin all, get all inner ring in each face, it joined respectively inner boundary ring collection L _in;

4th step: make L _boundary=L _out∪ L _in;

5th step: for L _boundaryin each element l _i, get l _iin each limit e ₁, e ₂..., e _n, the termination plane respectively to supporting construction is projection p ₁, p ₂..., p _n;

6th step: detect p ₁, p ₂..., p _nwhether can form closed-loop, if closed ring cannot be projected out, then carry out stitching process; Concrete processing procedure is:

First, for i=1,2 ..., n-1, calculates p _isummit with p _i+1summit between distance d ₁, d ₂, d ₃, d ₄, calculate d ₁~ d ₄between minimum value d _minif, d _min≤ ε, then without the need to carrying out stitching process;

Secondly, if d _min> ε, solves p and p _i+1between intersection point, if both exist intersection point, then replace p and p respectively with this intersection point _i+1the point that middle distance intersection point is nearer, if both do not exist intersection point, then at p and p _i+1in adjacent nearest point-to-point transmission make straight-line segment l, and will to be added in ring;

Finally, according to the method described above, to p ₁, p ₂..., p _nin adjacent between two projection do to sew up process;

Described (3.2) solve the bounding box of supporting construction, and detailed process is: with the face profile of trying to achieve in (3.1) for sketch, with the outgoing of profile place plane arrow n for draw direction makes stretch characteristic; Wherein, the computing method of the outer direction of normal of profile place plane are:

First, get above-mentioned steps 2) in any vertex v in user selects in (2.2) sub-step manifold _e, any vertex v of making even in facial contour _s, and do by v _spoint to v _evector v _s,e, make r=nv _s,eif, r>0, then the outer direction of normal of profile is n, otherwise is-n;

Then, with above-mentioned steps 2) in user selects in (2.2) sub-step manifold for shearing element, above-mentioned stretch characteristic is reduced;

Described (3.3) solve bounding box and be of a size of d on each direction of principal axis of coordinate system _x, d _ywith d _z.

3. a kind of paving of the aircraft structure based on space lattice powder sintering supporting construction generation method according to claim 1, it is characterized in that: the projector distance in described (4.1) computer memory dot matrix between each point, concrete grammar is for by step 2) in the projected length of Size calculation support bar in each direction of principal axis of coordinate system that input of sub-step (2.5), (2.6), computing formula is:

l _z＝l·sinθ；

In space lattice, each point is respectively l in the spacing in x, y, z direction _x, l _y, l _z;

The quantity that described (4.2) computer memory dot matrix is layouted on each direction of principal axis of coordinate system, specific formula for calculation is:

Described (4.3) determine the coordinate figure of each point in space lattice, and concrete grammar is:

First, according to the difference of the Z coordinate figure of each point in dot matrix, point is divided into n _z+ 2 layers, wherein, the point be positioned in coordinate system XOY plane is designated as the 1st layer;

Secondly, right if i is odd number, then remembering i-th layer in dot matrix is Primary layer; If i is even number, then remembering i-th layer in dot matrix is middle layer;

Finally, (n is arranged in the Primary layer in dot matrix _x+ 2) (n _y+ 2) individual point, if certain Primary layer be numbered k ₁, in this layer, the point that agreement x-axis coordinate figure is identical forms a line, and the some formation one that y-axis coordinate figure is identical arranges, then the i-th row, and the coordinate of jth row point is:

$\left\{\begin{array}{c}x=l_x\&CenterDot;(i-1),i\&Element;\{\mathrm{1,2},...,n_x+2\};\\ y=l_y\&CenterDot;(j-1),j\&Element;\{\mathrm{1,2},...,n_y+2\};\\ z=l_z\&CenterDot;(k_1-1),k_1\&Element;\{\mathrm{1,3},...,n_z+2\}.\end{array}\right.$

(n is arranged in the middle layer of dot matrix _x+ 1) (n _y+ 1) individual point, if certain middle layer be numbered k ₂, in this layer, the point that agreement x-axis coordinate figure is identical forms a line, and the some formation one that y-axis coordinate figure is identical arranges, then the i-th row, and the coordinate of jth row point is:

$\left\{\begin{array}{c}x=l_x\&CenterDot;(i-0.5),i\&Element;\{\mathrm{1,2},...,n_x+1\};\\ y=l_y\&CenterDot;(j-0.5),j\&Element;\{\mathrm{1,2},...,n_y+1\};\\ z=l_z\&CenterDot;(k_2-0.5),k_2\&Element;\{2,4,...,n_z+2\}.\end{array}\right.$

Described (4.4) judge the position relationship in space lattice between each point and supporting construction bounding box, concrete grammar is: for each point in space lattice, judge whether it is arranged in the bounding box of supporting construction, if point is arranged in entity bounding box, it is true for then marking current point, otherwise mark current point is false.

4. a kind of paving of the aircraft structure based on space lattice powder sintering supporting construction generation method according to claim 1, it is characterized in that: described (5.1) determine the endpoint number of each support bar, concrete grammar is:

For any point in middle layer, calculate another endpoint number of this some place support bar; Concrete grammar is: establish the layer at the some place in middle layer to be numbered k, and the row, column numbering at its place is respectively i, j, then there are at most 8 support bars at this some place, and the line number of another end points of these 8 support bars respectively is: i, i+1, i+1, i, i, i+1, i+1, i; Column number respectively is: j, j, j+1, j+1, j, j, j+1, j+1; Layer numbering respectively is: k-1, k-1, k-1, k-1, k+1, k+1, k+1, k+1;

Described (5.2), for creating support bar, concrete grammar is:

1., in the process creating supporting construction, be successively create support bar according to middle layer numbering order from small to large; In each middle layer, be create support bar line by line from small to large according to the line number of point; In each row, be create support bar one by one from small to large according to the column number of point;

2. create support bar to each point in middle layer, concrete steps are as follows:

The first step: judge the sequence number that is adjacent be 1 ~ 4 Primary layer end points whether possess support bar, if the layer of the end points of Primary layer is numbered 1, then think that these end points possess support bar; If four Primary layer end points all do not possess support bar, then do not create support bar at this some place; Otherwise turn second step;

Second step: be four Primary layer end points of 1 ~ 4 for sequence number, if end points possesses support bar, then judge between current point and Primary layer end points, to meet the condition creating support bar, if can satisfy condition, create support bar, and record this Primary layer end points and possess support bar; Otherwise do not create support bar;

3rd step: if the middle layer end points in second step and all dissatisfied condition creating support bar between four Primary layer end points, then terminate; Otherwise, judge sequence number be 5 ~ 8 four Primary layer end points whether meet the condition creating support bar, if meet, then create support bar, and record this Primary layer end points and possess support bar; Otherwise do not create support bar;

In above-mentioned second step and the 3rd step, the condition creating support bar between middle layer and Primary layer end points is determined by following rule:

Rule 1: if middle layer and Primary layer end points are all outside at supporting construction bounding box, then do not create support bar;

Rule 2: if middle layer and Primary layer end points are all inner at supporting construction bounding box or on bounding box border, then create support bar;

Rule 3: if be a bit positioned at supporting construction bounding box outside in middle layer and Primary layer end points, be not positioned at supporting construction bounding box outside, line between then doing at 2, judge this line and need to add between the manifold that supports whether there is intersection point, if there is intersection point, then create support bar, otherwise do not create support bar.

5. a kind of paving of the aircraft structure based on space lattice powder sintering supporting construction generation method according to claim 1, is characterized in that: described (6.1) merge support bar, and concrete grammar is:

1. solve the direction of each support bar, the direction of each support bar points to Primary layer end points by middle layer end points;

2. for all support bars, if direction is parallel, then by its point extremely same group, so, all support bars can be divided into four groups;

3. carry out merging treatment for each group support bar, concrete steps are:

The first step: create an empty chained list;

Second step: for arbitrary support bar, if current chained list is empty, is then added in chained list by support bar; Otherwise, judge each support bar in chained list can with its merging; In this step, judge that the rule that can two support bars merge is: if the middle layer endpoint number at two support bar places or Primary layer endpoint number identical, then two support bars can merge;

3rd step: if when front support rod can merge with the support bar of 1 in chained list, then change the endpoint number of support bar in chained list; If when front support rod can merge with the support bar of 2 in chained list, then using the endpoint number of the endpoint number after merging as support bar in chained list, and the support bar of redundancy in chained list is deleted;

Described (6.2) create supporting construction entity, concrete grammar is: for each chained list in (6.1), obtain each support bar element in chained list respectively, with the arbitrary end points of support bar for Plane-point, with support bar direction for sketch plane made by planar process arrow; With the cross sectional shape of user's input for sketch, with support bar direction for draw direction makes stretch characteristic;

Described (6.3) create the supplementing structure of supporting construction, and concrete grammar is: for each point in middle layer, if the support bar number at this place is greater than 0 and is less than 8, then create supplementing structure at this place, concrete creation method is:

If 1. user input cross sectional shape be circle, then with this point for the centre of sphere, the radius being ball with the section radius inputted makes entity ball;

If 2. user input cross sectional shape be rectangle, then with this point for the centre of sphere, with for radius makes entity ball;

If 3. user input cross sectional shape be regular polygon, then with this point for the centre of sphere, with regular polygon circumradius for radius makes entity ball;

Described (6.4) are the chamfering or the fillet that create supporting construction, concrete grammar is: according to step 2) in input chamfer radius or radius of corner, first sharp edges all in supporting construction is obtained, then the position of sharp edge is judged, adjacent sharp edge is returned to one group, often will organize sharp edge as an operand, carry out chamfering or fillet operation; In this step, judge that whether limit in part is that the method for sharp edge is as follows:

1. two manifold when place, front are obtained;

2. obtain when parameter mid point in front;

3. obtain the outer method pointed out in parameter in two faces respectively to vow;

If 4. two outer methods are vowed not parallel, then this limit is sharp edge, otherwise this limit is not sharp edge.