CN111361145B

CN111361145B - Multi-degree-of-freedom 3D printing method, device and system based on surface exposure

Info

Publication number: CN111361145B
Application number: CN202010187723.2A
Authority: CN
Inventors: 朱元杰; 赵明; 周绍林; 陈志坚; 李富华; 苏启聪
Original assignee: Bumint Foshan Photoelectric Technology Co ltd; South China University of Technology SCUT
Current assignee: Bumingte Foshan Optoelectronic Technology Co ltd
Priority date: 2020-03-17
Filing date: 2020-03-17
Publication date: 2021-06-15
Anticipated expiration: 2040-03-17
Also published as: CN111361145A

Abstract

The invention discloses a multi-degree-of-freedom 3D printing method based on a surface exposure type, relates to the technical field of 3D printing, and solves the technical problem that a large number of consumables are caused by the need of supporting during workpiece manufacturing. The method comprises the steps of firstly, partitioning a triangular surface patch on the surface of a printing model, normalizing the triangular surface patch in an area to obtain an external normal vector of the area, and putting the area and the corresponding external normal vector into an area set; and then searching the candidate substrate intersection surface and the parameters of the printing model, and finding out the cutting surface on the basis of the candidate substrate intersection surface and the area set, so that the printing model can perform unsupported printing by taking the candidate substrate intersection surface and the cutting surface as the bottom. The invention also discloses a multi-degree-of-freedom 3D printing device and system based on the surface exposure. The invention does not need to be supported, reduces the material consumption and improves the product quality. The variability of the manufacturing direction improves the flexibility of the slicing direction, increases the number of slicing layers and also improves the fineness of the model.

Description

Multi-degree-of-freedom 3D printing method, device and system based on surface exposure

Technical Field

The invention relates to the technical field of 3D printing, in particular to a multi-degree-of-freedom 3D printing method, device and system based on a surface exposure type.

Background

The 3D printing technique is also known as a rapid prototyping technique. Different from the traditional casting process, the 3D printing technology processes the manufactured workpiece through computer software, the manufactured workpiece is layered through supporting the manufactured workpiece, a path plan is generated, and the forming system achieves the purpose of manufacturing the workpiece according to the path plan. 3D printing technology is a novel rapid prototyping method, and nowadays, a plurality of rather mature printing methods such as FDM, SLA, DLP, SLM and the like have been derived, and all of them have respective advantages. However, in either method, it is inevitable to face the problem of setting and removing the print model support. The conventional printing method includes at least a planning step, a printing step, a support removing step, and a surface post-processing step in this order. The setting of the printing support has great influence on the printing model, and is also very important for post-processing of the model support after printing is finished, and the removal of the printing support particularly influences the surface fineness of the model; meanwhile, whatever support structure is added, the printing material is wasted. A model printed using a conventional printing apparatus is shown in fig. 1. Therefore, the support problem can be said to be a difficult problem to be solved urgently in the 3D printing technology.

Disclosure of Invention

The invention aims to solve the technical problem of the prior art, and aims to provide a surface exposure type-based multi-degree-of-freedom 3D printing method, which is free from supporting during workpiece manufacturing and effectively reduces consumables.

The second purpose is to provide a multi freedom 3D printing device based on face exposure formula, need not to add the support during preparation work piece, the effectual consumptive material that has reduced.

The third purpose is to provide a multi freedom 3D printing system based on face exposure formula, need not to add the support when preparation work piece, the effectual consumptive material that has reduced.

In order to achieve the first purpose, the invention provides a multi-degree-of-freedom 3D printing method based on a surface exposure type, which comprises a planning step and a printing step; the planning step is used for dividing a plurality of submodels capable of carrying out unsupported printing according to the surface parameters of the printing model and planning a printing path according to the submodels; and the printing step is used for finishing 3D printing according to the printing path obtained in the planning step.

The planning step includes:

s1, loading a printing model to obtain a triangular patch on the surface of the printing model and a normal vector thereof;

s2, partitioning the triangular patch of the printing model to obtain a plurality of area surfaces;

s3, normalizing the normal distribution of the triangular patches in each area plane to obtain an external normal vector corresponding to the normal distribution; the area surface and the corresponding external normal vector are used as a group and stored in an area set;

s4, searching candidate substrate intersecting surfaces, contour lines and normal vectors thereof for standardizing the initial printing direction on the outer surface of the printing model;

s5, determining cutting surfaces according to the candidate substrate intersection surfaces and the area set, so that the printing model is divided into a plurality of sub models capable of being subjected to unsupported printing;

s6, planning a complete printing path; and in the printing process, the printing step sequentially takes the intersecting surface and the cutting surface of the candidate substrate as the bottom, and the unsupported printing is carried out according to the printing path.

In S2, the method for dividing the triangular patches of the stamping-type surface by the division of the region growing method includes:

s21, scanning all vertexes of the printing model to determine a triangular patch capable of being used as a first seed patch;

s22, traversing a neighborhood patch of the seed patch, and if a normal included angle between the neighborhood patch and the seed patch is within a set specified value, adding the neighborhood patch into the seed patch to enable the seed patch to grow;

s23, continuing growing the neighborhood patches added into the seed patches as new seed patches until no new neighborhood patches are added, and completing the division of one region patch;

s24, detecting whether a triangular patch which does not belong to the area surface exists; if the triangular patches which are not assigned to the regional surface exist, one of the triangular patches which are not assigned to the regional surface is taken as a seed patch, and the steps from S22 to S23 are repeated until the partition is completed.

The set specified value is any value between 4 degrees and 6 degrees.

In S4, calibrating the intersection surface of the candidate substrate by a plurality of triangular patches on the outer surface of the printing model, wherein the triangular patches are the same with the external normal vector and the same plane; determining the contour line of the intersection surface of the candidate substrate through the outer edges of a plurality of triangular surface patches which are in the same outer normal vector and the same plane; and the normal vector of the intersection surface of the candidate substrate is consistent with the external normal vector of the triangular patch.

In S5, the method specifically includes:

s51, determining the range of normal vectors of all supportable area surfaces according to the normal vectors of the intersection surfaces of the candidate substrates, then starting scanning from the area surface farthest from the intersection surfaces of the candidate substrates, and searching for the common intersection of the normal vector ranges of the area surfaces adjacent to the farthest area surface;

s52, searching a normal vector with the maximum value in the common intersection as a normal vector of the cutting surface; determining a cutting contour meeting the requirement of non-collision printing according to the normal vector of the cutting surface, and determining a cutting surface according to the cutting contour;

s53, discarding the part of the area surface cut by the cutting surface from an area set, adding the area surface which is not cut into the area set, and adding the cutting surface into the area set;

s54, continuously scanning the area surface in the direction close to the intersection surface of the candidate substrate, finding out the common intersection of the normal vector ranges of the area surfaces which can support the adjacent area surfaces of the area surfaces, and then continuously determining the next cutting surface according to the steps of S52-S53;

and S55, repeating S54 until only two surfaces are left in the region set, wherein one surface is the candidate substrate intersection surface, and the other surface is the region surface which is consistent with the candidate substrate intersection surface in outline and is opposite to the normal direction.

And if the candidate substrate intersection surfaces are multiple, finding out all cutting surfaces corresponding to each candidate substrate intersection surface, and taking an optimal candidate substrate intersection surface and the optimal cutting surface thereof.

The included angle between the normal vector of the supportable area surface and the normal vector of the area surface is 0-pi/2 + theta_{z_max}To (c) to (d);

wherein, theta_{z_max}A maximum dip angle at which the printing model can be printed without support;

the included angle between the normal vector with the maximum value and the normal vector of the intersection surface of the candidate substrate is 0-theta_{j_max}And the smaller the included angle of the normal vector of the intersecting surface of the candidate substrate is, the larger the value of the normal vector of the cutting surface is;

wherein, theta_{j_max}And the maximum inclination angle allowed by the supporting platform for supporting the printing model for the 3D printer and the horizontal plane.

In order to achieve the second purpose, the invention provides a multi-degree-of-freedom 3D printing device based on a surface exposure type, which comprises a control component, a printing component, a driving component, a supporting component with adjustable degree of freedom and an exposure component for curing a printing mould, wherein the control component is respectively electrically connected with the printing component and the driving component, the driving component is connected with the supporting component, and the exposure component is positioned below the supporting component; by applying the multi-degree-of-freedom 3D printing method based on the surface exposure type, the control component controls the driving component and the printing component after planning the printing path, so that the printing component completes 3D printing on the supporting component.

In order to achieve the third objective, the invention provides a multi-degree-of-freedom 3D printing system based on a surface exposure type, comprising:

the main control module is used for dividing a plurality of submodels capable of carrying out unsupported printing according to the surface parameters of the printing model and planning a printing path according to the submodels;

and the printing module is used for finishing 3D printing according to the printing path obtained in the planning step.

Advantageous effects

The invention has the advantages that: the method comprises the steps of partitioning a triangular patch on the surface of a printing model, normalizing the triangular patch in an area to obtain an external normal vector of the area, and putting the area and the corresponding external normal vector into an area set; and then searching the candidate substrate intersection surface and the parameters of the printing model, and finding out the cutting surface on the basis of the candidate substrate intersection surface and the area set, so that the printing model can perform unsupported printing by taking the candidate substrate intersection surface and the cutting surface as the bottom. Printing by the printing method of the present application reduces two necessary steps in the prior art, namely, a step of removing support and a step of surface post-treatment, compared to conventional printing processes. No support is needed to be added to the printing mould, so the loss of raw materials of the printing mould is reduced; the step of surface post-processing is omitted, the post-processing procedure is simplified, the printing model is more convenient, the surface of the printing model is more delicate, and the product quality is greatly improved.

Drawings

FIG. 1 is a cut-away view of a model printed by a conventional printing device;

FIG. 2 is a cut-away view of a model printed by the printing apparatus of the present invention;

FIG. 3 is a schematic flow chart of the present invention;

FIG. 4 is a schematic diagram of a printing apparatus according to the present invention;

fig. 5 is a schematic structural view of the driving assembly and the supporting assembly of the present invention.

Wherein: the device comprises a support 1, a top plate 2, a middle plate 3, a bottom plate 4, a resin tank 5, a driving motor 6, a parallel plate 7, a first metal block 8, a second metal block 9, a metal rod 10, a ball screw 11, a sliding block 12, a sliding rod 13, a spherical hinge structure 14, a movable platform 15, a printing substrate 16, a DLP projector 17 and a reflector 18.

Detailed Description

The invention is further described below with reference to examples, but not to be construed as being limited thereto, and any number of modifications which can be made by anyone within the scope of the claims are also within the scope of the claims.

Referring to fig. 3, the surface exposure type-based multi-degree-of-freedom 3D printing method according to the present invention includes a planning step and a printing step. And the planning step is used for dividing a plurality of sub models capable of carrying out unsupported printing according to the surface parameters of the printing model and planning a printing path according to the sub models. And the printing step is used for finishing 3D printing according to the printing path obtained in the planning step.

The planning step specifically comprises:

and S1, loading the printing model to obtain a triangular patch of the surface of the printing model and a normal vector thereof. Specifically, the loaded printing model is a triangular patch model in an STL format, so that a series of points, triangular patches and normal vectors thereof are obtained; and then respectively establishing point sequences and storing corresponding triangular surface patch relations, such as normal and normal vectors thereof.

And S2, partitioning the triangular patch of the printing model to obtain a plurality of area faces. The present embodiment uses a zone-growing zoning approach to zone the triangular facets of the stamping-type surface. The partition mode of the region growth specifically comprises the following steps:

and S21, scanning all the vertexes of the printing model to determine a triangular patch which can be used as a first seed patch. Specifically, the vertex in this embodiment refers to a point coordinate containing the X, Y, or Z maximum value among all point coordinates, and it is better to use a triangular patch containing the vertex as a seed patch, so that the partitioning effect is better.

And S22, traversing the neighborhood patches of the seed patches, and if the normal included angle between the neighborhood patches and the seed patches is within a set specified value, adding the neighborhood patches into the seed patches to enable the seed patches to grow. Wherein the prescribed value is set to any value between 4 ° and 6 °.

And S23, continuing growing the neighborhood patches added into the seed patches as new seed patches until no new neighborhood patches are added, and completing the division of a region patch.

S24, detecting whether a triangular patch which does not belong to the regional patch exists; if the triangular patches which are not assigned to the regional surface exist, one of the triangular patches which are not assigned to the regional surface is taken as a seed patch, and the steps from S22 to S23 are repeated until the partition is completed. In this embodiment, the growth of the region surface is started after the growth of one region surface is completed, and the independent triangular surface patch which is not partitioned is regarded as the triangular surface patch which is not belonging to the region surface. The new region face is grown with an undivided triangular patch as the seed patch, which is randomly drawn among all the independent triangular patches. All independent triangular patches are partitioned to summarize huge triangular patch information into relatively small number of area patches, so that the system operation is facilitated, and the problem that the system operation is too slow due to excessively large data is avoided.

In the process of region growing, if the normal change of the region surface is smooth when the region is divided, an overlarge region surface can be divided; and if the quantity of outward normal included angles of the vertexes existing in the area is larger than a certain specified value, the area needs to be subdivided. Wherein the prescribed value may take 90 °. The method for subdividing the area comprises the following steps: the direction with the largest normal change in the region is obtained by utilizing a principal component analysis method, then the direction is taken as a normal vector, a plane passing through the center point of the region is made, and the plane divides the region into two regions, so that the overlarge region surface is divided into two region surfaces.

S3, after the area faces are divided, normalizing the normal distribution of the triangular patch in each area face to obtain an external normal vector corresponding to the area face; and then the area surface and the corresponding external normal vector are stored in an area set as a group.

And S4, searching candidate substrate intersecting surfaces for standardizing the initial printing direction, contour lines and normal vectors thereof on the outer surface of the printing model. Specifically, in the step, the intersection surface of the candidate substrate is calibrated by printing a plurality of triangular patches on the outer surface of the model, wherein the triangular patches are the same with the external normal vector and the same plane. And the candidate substrate intersecting surface is a candidate surface of the printing model initial surface. And determining the contour lines of the intersecting surfaces of the candidate substrates through the outer edges of a plurality of triangular patches which are in the same plane and have the same outer normal vector. And the normal vector of the intersection surface of the candidate substrate is consistent with the external normal vector of the triangular patch.

And S5, determining cutting surfaces according to the candidate substrate intersection surfaces and the area set so as to divide the printing model into a plurality of sub models capable of carrying out unsupported printing. The method specifically comprises the following steps:

and S51, determining the range of the normal vectors of all supportable area surfaces according to the normal vectors of the intersection surfaces of the candidate substrates. In this embodiment, on the basis of knowing the normal vectors of the intersecting surfaces of the candidate substrates, the normal vector ranges of all the corresponding cutting surfaces can be determined, and the ranges and 0-theta can be determined_{j_max}(ii) related; and the normal vector of the supportable area surface is the normal vector of the cutting surface. Wherein, theta_{j_max}And the maximum inclination angle allowed by the supporting platform for supporting the printing model for the 3D printer and the horizontal plane. For example, the intersecting surface of the candidate substrate in fig. 2 is the bottom surface of a cone, the contour is circular, the normal vector direction of the intersecting surface of the candidate substrate is perpendicular to the circular contour surface and points from the inside of the model to the outside of the model, i.e., the vertical downward direction in the figure, and the included angle between the normal vector of all the cutting surfaces and the vertical upward direction is 0-theta_{j_max}In the meantime.

In addition, the included angle between the normal vector of the supportable area surface and the normal vector of the area surface is 0-pi/2 + theta_{z_max}In the meantime. Wherein, theta_{z_max}Maximum dip angle at which the model can be printed unsupported. Then, scanning is started from the area surface farthest from the intersection surface of the candidate substrate, and a common intersection of the normal vector ranges of the area surfaces adjacent to the farthest area surface and the supportable area surface is searched.

For several adjacent area surfaces, a smaller range of normal vectors of the cutting surfaces is included, the range is the common intersection of the ranges of normal vectors of the cutting surfaces which can support the adjacent area surfaces, and one direction is selected as the normal vector of the cutting surface. If the range size of the common intersection is smaller than a certain threshold range or the common intersection is an empty set, the number of the area surfaces is reduced to find the appropriate number of the adjacent area surfaces and the appropriate common intersection, and the normal vector of the selected cutting surface can support the area surfaces.

S52 method for finding maximum value in common intersectionThe vector is taken as the normal vector of the cutting surface. Specifically, the angle between the normal vector with the highest value and the normal vector of the intersection surface of the candidate substrate should be 0-theta_{j_max}And the smaller the angle of the normal vector of the intersecting surface with the candidate substrate, the larger the value of the normal vector of the cutting surface. Wherein, theta_{j_max}And the maximum inclination angle allowed by the supporting platform for supporting the printing model for the 3D printer and the horizontal plane. And determining a cutting profile meeting the requirement of non-collision printing according to the normal vector of the cutting surface, and determining a cutting surface through the cutting profile.

After the normal vector of the cutting surface is selected, the position and the contour of the cutting surface are determined by scanning in reverse direction along the normal vector of the cutting surface until the normal vector of the cutting surface touches the area surface outside the corresponding area surface or does not meet the non-collision printing condition, and recording the position and the contour of the normal vector of the cutting surface, namely the cutting surface.

Further, to satisfy collision-free printing, it is necessary to avoid collisions in two respects. The first is to avoid collision of the printed substrate with the resin bath, and the second is to avoid collision of the printed portion with the resin bath. In order to meet the first requirement, the planes of all the cut surfaces and the plane of the candidate substrate intersection surface intersect outside the printing substrate. In order to meet the second requirement, each cutting surface is searched to ensure that the cut section is a single communication area. I.e. any point on the cross-section can go to any point on the cross-section through other points in the cross-section.

And S53, discarding the part of the area surface cut by the cutting surface from the area set, adding the area surface which is not cut into the area set, and adding the cutting surface into the area set, thereby completing the construction of the unsupported printing sub-model.

S54, continuing to scan the area surface in the direction close to the intersection surface of the candidate substrates, finding out the common intersection of the normal vector ranges of the area surfaces which can support the adjacent area surfaces of the area surfaces, and continuing to determine the next cutting surface according to the steps S52-S53.

And S55, repeating S54 until only two surfaces are left in the region set, wherein one surface is the candidate substrate intersection surface, and the other surface is the region surface which is consistent with the candidate substrate intersection surface in outline and is opposite to the normal direction. The cutting surface realizes that the printing model is divided into a plurality of sub-models which can be subjected to unsupported printing.

If the candidate substrate intersection surfaces are multiple, all cutting surfaces corresponding to each candidate substrate intersection surface are found out, and an optimal candidate substrate intersection surface and the optimal cutting surfaces thereof are selected. And after the cutting surface corresponding to each candidate substrate intersection surface is known, the height of each submodel is obtained, then the heights of the submodels corresponding to each candidate substrate intersection surface are summed and compared, and the group with the minimum height is the optimal candidate substrate intersection surface and the cutting surface thereof. The printing time of the intersecting surface and the cutting surface of the candidate substrate group is shortest, and the efficiency is highest.

S6, planning a complete printing path; and in the printing process, the printing step sequentially takes the intersecting surface and the cutting surface of the candidate substrate as the bottom, and the unsupported printing is carried out according to the printing path. During printing, the intersection surface of the candidate substrate is taken as an initial surface, and unsupported printing is firstly carried out on the sub-model at the bottommost layer; then, using the cutting surface on the sub-model at the bottommost layer as the bottom, and carrying out unsupported printing on the corresponding sub-model; and printing is carried out until all the sub models are printed, so that the printing of the printing model is finished.

In the embodiment, the triangular surface patches on the surface of the printing mould are partitioned, the triangular surface patches in the area are normalized to obtain the external normal vector of the area surface, and the area surface and the corresponding external normal vector are put into an area set; and then searching the candidate substrate intersection surface and the parameters of the printing model, and finding out the cutting surface on the basis of the candidate substrate intersection surface and the area set, so that the printing model can perform unsupported printing by taking the candidate substrate intersection surface and the cutting surface as the bottom. Compared with the traditional printing process, the printing method does not need to add support to the printing mould when printing, so that the loss of raw materials is reduced; meanwhile, the post-processing step of removing the support is omitted, the post-processing procedure is simplified, the printing model is more convenient, the surface of the printing model is more delicate, and the product quality is greatly improved.

Referring to fig. 4-5, a multi-degree-of-freedom 3D printing apparatus based on a surface exposure type includes a control component, a printing component, a driving component, a support component with adjustable degree of freedom, and an exposure component for curing a printing mold. The control assembly is respectively and electrically connected with the printing assembly and the driving assembly, the driving assembly is connected with the supporting assembly, and the exposure assembly is positioned below the supporting assembly. The multi-degree-of-freedom 3D printing method based on the surface exposure type is applied, the driving assembly and the printing assembly are controlled after the printing path is planned by the control assembly, and therefore the printing assembly can finish 3D printing on the supporting assembly.

The printing apparatus of the present embodiment further includes a carriage 1. The control assembly and the printing assembly are both arranged on the bracket 1. The bracket 1 is provided with a top plate 2, a middle plate 3 and a bottom plate 4, and the driving component is arranged on the top plate 2. The supporting assembly with adjustable degree of freedom is arranged on the driving assembly; the middle layer plate 3 is detachably provided with a resin tank 5, and the resin tank 5 is positioned between the support component and the exposure component; the exposure assembly is mounted on the bottom plate 4.

The control assembly divides the printing model into a plurality of sub-models which can be printed without support, plans a printing path, and then adjusts the support assembly through the driving assembly according to the printing path so that the printing assembly prints the sub-models on the support assembly; and exposure curing is carried out through an exposure component positioned below the resin tank 5, so that unsupported printing of the printing model is realized.

The drive assembly of this embodiment comprises six drive motors 6 mounted on the top deck 2, a parallel plate 7, and a slide 12. First metal blocks 8 with the number identical to that of the driving motors 6 are installed on the parallel plates 7, second metal blocks 9 corresponding to the first metal blocks 8 one by one are installed at the bottom of the top plate 2 located right above the first metal blocks 8, and the first metal blocks 8 are connected with the second metal blocks 9 through two metal rods 10. A ball screw 11 is arranged between the metal rods 10, a slide block 12 is slidably arranged on the metal rods 10 and the ball screw 11, and the ball screw 11 is connected with a rotor of the driving motor 6. The bottom of the sliding block 12 is provided with a sliding rod 13 which sequentially penetrates through the first metal block 8 and the parallel plate 7.

The support assembly comprises a ball and socket joint structure 14 and a moveable platform 15. One end of the spherical hinge structure 14 is hinged with the end of the sliding rod 13, the other end is connected with the movable platform 15, a printing substrate 16 is arranged below the movable platform 15, and the resin tank 5 is positioned below the printing substrate 16. Specifically, the printing substrate 16 is fixed on the movable platform 15 in parallel by three columnar structures. The resin tank 5 is fixed to the middle plate 3 by bolts at both sides thereof.

The ball screw 11 is driven by the driving motor 6, so that the slide block 12 arranged on the ball screw 11 drives the slide rod 13 to move vertically. The sliding rod 13 drives the moving platform 15 to perform horizontal translation movement, vertical movement and tilting movement through the spherical hinge structure 14, so that the movement of the printing substrate 16 is realized, and the degree of freedom of the printing substrate 16 is adjustable.

The exposure assembly of the present embodiment includes a DLP projector 17 and a mirror 18. The DLP projector 17 and the mirror 18 are both fixed to the bottom plate 4. The central part of the middle layer plate 3 is hollow, and the bottom of the resin groove 5 is a transparent bottom, so that the DLP projector 17 can expose and cure the resin in the resin groove 5. Through coordinating driving motor 6 and DLP projecting apparatus 17, this printing device can satisfy the photocuring 3D printing demand of multi freedom.

The printing model is divided into a plurality of sub-models capable of being printed without support through a cutting surface, and when printing is carried out, the control assembly firstly adjusts the position of the printing substrate 16, so that the printing assembly can carry out the printing without support on the sub-models at the bottom layer. Then, the control component continuously adjusts the printing substrate 16 according to the planned printing path, so that the printing component can perform unsupported printing on the corresponding sub-model by taking the cutting surface on the sub-model at the bottom layer as the bottom; and the cutting surface is used as the bottom in sequence to perform unsupported printing of other submodels, and finally, the submodels are printed layer by layer on a printing substrate one by using a printing device with multiple degrees of freedom. Compared with the traditional printing equipment manufacturing process, the printing device does not need to be supported, so that the step of removing the support is not needed in the post-treatment, the residual resin trace after the support is removed is avoided, and the product quality is improved while the consumable material is reduced. The variability of the manufacturing direction improves the flexibility of the slicing direction, increases the number of slicing layers and also improves the fineness of the model.

A multi-degree-of-freedom 3D printing system based on a surface exposure type can be loaded and operated by a computer, is used for realizing the multi-degree-of-freedom 3D printing method, and can be used for controlling a multi-degree-of-freedom 3D printing device. The multi-degree-of-freedom 3D printing system specifically comprises a main control module and a printing module.

The main control module is used for dividing a plurality of submodels capable of carrying out unsupported printing according to the surface parameters of the printing model and planning a printing path according to the submodels. And the printing module is used for finishing 3D printing according to the printing path obtained in the planning step.

The printing model is divided into a plurality of sub-models capable of being subjected to unsupported printing through the surface parameters of the printing model, and then the sub-models are subjected to unsupported printing in sequence according to the planned printing path, so that the unsupported printing of the printing model is realized. Compared with the traditional printing process, the printing method does not need to add support to the printing mould when printing, so that the loss of raw materials is reduced; meanwhile, the post-processing step of removing the support is omitted, the post-processing procedure is simplified, the printing model is more convenient, the surface of the printing model is more delicate, and the product quality is greatly improved.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that those skilled in the art can make various changes and modifications without departing from the structure of the invention, which will not affect the effect of the invention and the practicability of the patent.

Claims

1. A multi-degree-of-freedom 3D printing method based on a surface exposure type is characterized by comprising a planning step and a printing step; the planning step is used for dividing a plurality of submodels capable of carrying out unsupported printing according to the surface parameters of the printing model and planning a printing path according to the submodels; the printing step completes 3D printing according to the printing path obtained in the planning step;

the planning step specifically comprises:

s1, loading the printing model to obtain a triangular patch on the surface of the printing model and a normal vector thereof;

s6, planning a complete printing path; when printing, the printing step sequentially takes the intersecting surface and the cutting surface of the candidate substrate as the bottom, and carries out unsupported printing according to the printing path;

in S4, calibrating the intersection surface of the candidate substrate by a plurality of triangular patches on the outer surface of the printing model, wherein the triangular patches are the same with the external normal vector and the same plane; determining the contour line of the intersection surface of the candidate substrate through the outer edges of a plurality of triangular surface patches which are in the same outer normal vector and the same plane; the normal vector of the intersection surface of the candidate substrate is consistent with the external normal vector of the triangular patch;

in S5, the method specifically includes:

2. The method for multi-degree-of-freedom 3D printing based on surface exposure according to claim 1, wherein in S2, the method for partitioning the triangular patches of the printing mold surface by using the partition method of region growing specifically comprises:

3. The surface exposure based multiple degree of freedom 3D printing method according to claim 2, wherein the setting specified value is any one of values between 4 ° and 6 °.

4. The surface exposure-based multi-degree-of-freedom 3D printing method according to claim 1, wherein if there are a plurality of candidate substrate intersection surfaces, all cut surfaces corresponding to each candidate substrate intersection surface are found, and an optimal one of the candidate substrate intersection surfaces and its cut surface is selected.

5. The surface exposure type multiple-degree-of-freedom 3D printing method according to claim 1, wherein an included angle between a normal vector of the supportable region surface and a normal vector of the region surface is 0-pi/2 + theta_{z_max}To (c) to (d);

6. A multi-degree-of-freedom 3D printing device based on a surface exposure type comprises a control assembly, a printing assembly, a driving assembly, a supporting assembly with adjustable degree of freedom and an exposure assembly for curing a printing mold, wherein the control assembly is electrically connected with the printing assembly and the driving assembly respectively, the driving assembly is connected with the supporting assembly, and the exposure assembly is positioned below the supporting assembly; the surface exposure based multi-degree-of-freedom 3D printing method is characterized in that the control assembly is used for controlling the driving assembly and the printing assembly after a printing path is planned, so that the printing assembly can complete 3D printing on the supporting assembly.

7. A multi-degree-of-freedom 3D printing system based on a surface exposure type is characterized by comprising:

the printing module is used for finishing 3D printing according to the printing path obtained in the planning step;

the planning step specifically comprises:

in S5, the method specifically includes: