CN118106506A

CN118106506A - Dimension compensation method, device, equipment and medium for additive manufacturing part

Info

Publication number: CN118106506A
Application number: CN202410237280.1A
Authority: CN
Inventors: 范小寒; 王朝龙; 孙宇成; 冯晓宏
Original assignee: Hunan Farsoon High Tech Co Ltd
Current assignee: Hunan Farsoon High Tech Co Ltd
Priority date: 2024-03-01
Filing date: 2024-03-01
Publication date: 2024-05-31

Abstract

The invention relates to the technical field of 3D printing and discloses a size compensation method, device, equipment and medium of an additive manufacturing part. Further, iterative optimization is carried out through the constructed target data set until a target size compensation function for controlling the size precision in the whole forming space is obtained, and finally the target size compensation function and the selective laser sintering technology are used for processing, so that the target additive manufactured part after size compensation can be obtained, and the size precision of the additive manufactured part to be compensated is improved.

Description

Dimension compensation method, device, equipment and medium for additive manufacturing part

Technical Field

The invention relates to the technical field of 3D printing, in particular to a size compensation method, a device, equipment and a medium for additive manufacturing parts.

Background

The basic process of the selective laser sintering process is as follows: the powder feeding device feeds a certain amount of powder to the workbench surface, the powder laying roller lays a layer of powder material on the upper surface of a powder bed containing formed parts of the forming cylinder, the heating device heats the powder to a set temperature, and the vibrating mirror system controls the laser to scan the powder layer of the solid part according to the section profile of the layer, so that the powder is melted and bonded with the formed part below; after the sintering of one layer of section is completed, the workbench is lowered by one layer of thickness, the powder spreading roller is spread with one layer of uniform and compact powder, the scanning sintering of a new layer of section is carried out, and a plurality of layers of scanning and superposition are carried out until the whole part manufacturing is completed.

In the whole processing process, the formed polymer workpieces are positioned at different positions of the forming space, the pressure of the top powder or other workpieces is different, and in the cooling process, the heat dissipation speed is different, and the difference can lead to the difference of the crystallization shrinkage degree of the workpieces at different positions of the forming space to cause the size difference.

Disclosure of Invention

In view of the above, the present invention provides a size compensation method, device, equipment and medium for additive manufacturing parts, so as to solve the problem of size difference caused by different degrees of crystallization shrinkage of the formed polymer workpiece at different positions of the forming space due to different pressures and heat dissipation speeds in the selective laser sintering forming and cooling process.

In a first aspect, the present invention provides a method of dimensional compensation of an additive manufactured part, the method comprising:

acquiring a to-be-compensated workpiece stl model of a to-be-compensated additive manufacturing part, arranging the to-be-compensated workpiece stl model in a forming space, acquiring a plurality of initial coordinate values and a plurality of triangular vertex coordinate values of the to-be-compensated workpiece stl model based on a forming space coordinate system, wherein the forming space represents a space for forming a workpiece in a forming equipment cabin in a selective laser sintering technology, the forming space coordinate system is a Cartesian coordinate system established in the forming space, and the origin of the coordinate system is located at any point in the forming space; obtaining a dimension error value of the additive manufactured part to be compensated through a preset processing method based on a preset dimension compensation function, a preset scaling center and a plurality of triangular surface vertex coordinate values; constructing a target data set based on a plurality of initial coordinate values, a preset size compensation function, a preset scaling center and a size error value, wherein the target data set is used for calculating each coefficient value of the size compensation function in the direction of a single coordinate axis or calculating the variation of each coefficient value of the size compensation function in the direction of the single coordinate axis; determining a target size compensation function through a preset calculation method and an iterative optimization method based on a target data set; and processing the workpiece stl model to be compensated by a target size compensation function and a selective laser sintering technology to obtain the size compensated target additive manufactured part.

According to the dimension compensation method for the additive manufactured part, position compensation is carried out on a plurality of triangular surface vertex coordinate values of a workpiece stl model to be compensated, which are arranged in a forming space, according to a preset dimension compensation function, a dimension error value of the additive manufactured part to be compensated is obtained, and meanwhile, a target data set for calculating each coefficient value of the dimension compensation function in the direction of a single coordinate axis or for calculating the variation of each coefficient value of the dimension compensation function in the direction of the single coordinate axis is constructed by combining the dimension error value. Further, iterative optimization is carried out through the constructed target data set until a target size compensation function for controlling the size precision in the whole forming space is obtained, and finally the target size compensation function and the selective laser sintering technology are used for processing, so that the target additive manufactured part after size compensation can be obtained, and the size precision of the additive manufactured part to be compensated is improved.

In an alternative embodiment, obtaining the dimension error value of the additive manufactured part to be compensated through a preset processing method based on a preset dimension compensation function, a preset scaling center and a plurality of triangular surface vertex coordinate values includes:

Calculating a scaling factor based on a preset size compensation function and a plurality of triangular surface vertex coordinate values; scaling the workpiece stl model to be compensated by utilizing the vertex coordinate values of the triangular faces, a preset scaling center and scaling coefficients to obtain a scaled workpiece stl model to be compensated; and processing the scaled workpiece stl model to be compensated by using a selective laser sintering technology and obtaining a size error value.

According to the size compensation method for the additive manufactured part, the calculated scaling coefficient is combined with the preset scaling center and the obtained triangular surface vertex coordinate values of the to-be-compensated workpiece stl model, scaling can be carried out on the to-be-compensated workpiece stl model, further, the size error value of the to-be-compensated workpiece stl model can be obtained through sintering treatment by the selective laser sintering technology, and data support is provided for subsequently improving the size precision of the to-be-compensated additive manufactured part.

In an alternative embodiment, scaling the workpiece stl model to be compensated by using a plurality of triangular plane vertex coordinate values, a preset scaling center and a scaling coefficient to obtain a scaled workpiece stl model to be compensated, including:

Calculating a distance value between each triangular surface vertex and a preset scaling center based on the coordinate values of the triangular surface vertices and the preset scaling center; determining a plurality of triangular surface vertex coordinate values of the scaled workpiece stl model to be compensated based on a plurality of distance values, a preset scaling center and a scaling coefficient; and determining the scaled workpiece stl model to be compensated based on the coordinate values of the vertexes of the triangular surfaces of the scaled workpiece stl model to be compensated.

According to the dimension compensation method for the additive manufactured part, the coordinate values of the scaled triangular surface vertexes can be determined by combining the preset scaling center, the scaling coefficient and the calculated distance value between each triangular surface vertex and the preset scaling center, and further, the corresponding scaled workpiece stl model to be compensated can be determined and obtained, so that support is provided for subsequently improving the dimension precision of the additive manufactured part to be compensated.

In an alternative embodiment, determining the target size compensation function based on the target data set through a preset calculation method and an iterative optimization method includes:

calculating a plurality of function coefficient values based on the target data set; determining an initial size compensation function based on the plurality of function coefficient values; and returning to the step of acquiring the stl model of the workpiece to be compensated of the additive manufacturing part to be compensated based on the initial size compensation function, and repeatedly iterating until the size precision of the stl model of the workpiece to be compensated reaches the preset requirement, so as to obtain the target size compensation function.

According to the dimension compensation method for the additive manufactured part, provided by the invention, the target dimension compensation function for controlling the dimension precision in the whole forming space can be obtained through iterative optimization, and support is provided for subsequently improving the dimension precision of the additive manufactured part to be compensated.

In an alternative embodiment, calculating a plurality of function coefficient values based on the target data set includes:

constructing a first equation set based on the target data set, wherein the first equation set is used for representing the corresponding relation between the target data set and the function coefficient value; and solving the first equation set to obtain a plurality of function coefficient values.

In an alternative embodiment, calculating the plurality of function coefficient values based on the target data set further comprises:

Constructing a second equation set based on the target data set, wherein the second equation set is used for representing the corresponding relation between the target data set and the variable quantity of the function coefficient value; solving the second equation set to obtain a plurality of variable quantities; a plurality of function coefficient values are calculated based on the plurality of variation amounts.

In an alternative embodiment, calculating the scaling factor based on the preset size compensation function and the plurality of triangular face vertex coordinate values includes: the scaling factor is calculated by the relationship:

Wherein: x _ori,y_ori,z_ori represents an original coordinate value of a triangular surface vertex of the stl model of the workpiece to be compensated in a molding space coordinate system; Representing a scaling factor of a single coordinate axis direction calculated by a preset size compensation function at a triangular surface vertex of a workpiece stl model to be compensated with a coordinate x _ori,y_ori,z_ori in a molding space coordinate system; i, j, k represent the index value of an original coordinate x _ori,y_ori,z_ori of a triangular surface vertex of a workpiece stl model to be compensated in a forming space coordinate system in a preset size compensation function; m represents the control value of the index value of i, j, k; p _ijk represents the coefficient value corresponding to the independent variable of which the x _ori,y_ori,z_ori index value is i, j and k in the preset size compensation function respectively; the values of m, i, j, k are 0, 1, 2,3 or 4, i+j+k.ltoreq.m.

In a second aspect, the present invention provides a dimensional compensation apparatus for an additive manufactured part, the apparatus comprising:

the arrangement and acquisition module is used for acquiring a to-be-compensated workpiece stl model of the to-be-compensated additive manufacturing part, arranging the to-be-compensated workpiece stl model in a forming space, acquiring a plurality of initial coordinate values and a plurality of triangular surface vertex coordinate values of the to-be-compensated workpiece stl model based on a forming space coordinate system, wherein the forming space represents a space for forming a workpiece in a forming equipment cabin in a selective laser sintering technology, and the forming space coordinate system is a Cartesian coordinate system established in the forming space, and the origin of the coordinate system is at any point in the forming space; the processing module is used for obtaining the dimension error value of the additive manufactured part to be compensated through a preset processing method based on a preset dimension compensation function, a preset scaling center and a plurality of triangular surface vertex coordinate values; the construction module is used for constructing a target data set based on a plurality of initial coordinate values, a preset size compensation function, a preset scaling center and a size error value, wherein the target data set is used for calculating each coefficient value of the size compensation function in the direction of a single coordinate axis or calculating the variation of each coefficient value of the size compensation function in the direction of the single coordinate axis; the determining module is used for determining a target size compensation function based on the target data set through a preset calculation method and an iterative optimization method; and the processing module is used for processing the workpiece stl model to be compensated through a target size compensation function and a selective laser sintering technology to obtain the target additive manufactured part after size compensation.

In a third aspect, the present invention provides a computer device comprising: the device comprises a memory and a processor, wherein the memory and the processor are in communication connection, the memory stores computer instructions, and the processor executes the computer instructions, so that the dimension compensation method of the additive manufactured part in the first aspect or any corresponding embodiment of the first aspect is executed.

In a fourth aspect, the present invention provides a computer readable storage medium having stored thereon computer instructions for causing a computer to perform the method of dimension compensation of an additive manufactured part of the first aspect or any of its corresponding embodiments.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic illustration of a workpiece in position in a forming space according to an embodiment of the invention;

FIG. 2 is a flow chart of a method of dimension compensation of an additive manufactured part according to an embodiment of the present invention;

FIG. 3 is a flow chart of another method of dimension compensation of an additive manufactured part according to an embodiment of the invention;

FIG. 4 is a flow chart of a method of dimension compensation of yet another additive manufactured part according to an embodiment of the invention;

FIG. 5 is a flow chart of a method of dimensional compensation of a part data model according to an embodiment of the invention;

Fig. 6 is a schematic view of a rectangular workpiece having dimensions of 6.5mm by 100mm in accordance with an embodiment of the present invention;

FIG. 7 is a schematic diagram of a Cartesian coordinate system established in a molding space according to an embodiment of the present invention;

Fig. 8A is a top view of the placement position of the rectangular parallelepiped workpiece stl in the forming space according to the embodiment of the present invention;

Fig. 8B is a front view of the placement position of the rectangular parallelepiped workpiece stl in the forming space according to the embodiment of the present invention;

FIG. 9 is a diagram of measured distance dimensions and error values for an actual molded cuboid stl workpiece according to an embodiment of the present invention;

FIG. 10 is a diagram of the measured distance dimension and error value of an actual formed cuboid stl workpiece in a second cycle according to an embodiment of the present invention;

FIG. 11 is a block diagram of a dimension compensation device for an additive manufactured part according to an embodiment of the invention;

Fig. 12 is a schematic diagram of a hardware structure of a computer device according to an embodiment of the present invention.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In the selective laser sintering process, as shown in fig. 1, the formed part is positioned at the lower part of the forming space, so that part or whole of the earlier formed workpiece is subjected to the pressure of the upper powder or other workpiece or part of the workpiece, the forming space is kept at a higher temperature in the whole process, the earlier formed workpiece is kept at a higher temperature for a longer time, the crystallization shrinkage of the macromolecule workpiece positioned at the lower part in the whole forming space is larger, and the dimension of the perpendicular forming space in the horizontal plane direction of the different workpieces or the dimension difference of the perpendicular forming space in the horizontal plane direction of the same workpiece in the different height positions of the perpendicular forming space in the horizontal plane direction of the perpendicular forming space are caused; because the powder will agglomerate and harden when heated for a long time, in order to prevent the problem of powder spreading when the workbench descends, the temperature of the heater at the edge of the forming space will be set at a temperature lower than the top surface of the forming space, and in the process, the accumulated heat in the forming process will flow from a high temperature area to a low temperature area, so that the temperature in the center of the forming space is higher than the peripheral temperature for a long time, the crystallization shrinkage of the workpiece at the center of the forming space will be obviously larger than that of the workpiece at the periphery of the forming space, and the size of different workpieces on the horizontal surface of the forming space in the vertical forming space horizontal direction or the size difference of the same workpiece in the vertical forming space horizontal direction at different height positions will be caused.

In one example, dimensional shrinkage differential data resulting from the combined effects of pressure, temperature and time are shown in table 1 below:

TABLE 1 number of dimensional shrinkage differences due to common influences of pressure, temperature and time

Numbering device	Measured dimension mm	Error mm
			1	95.34	0.34
2	95.26	0.26
			3	95.37	0.37
4	95.2	0.2
			5	95.04	0.04
6	95.28	0.28
			7	95.46	0.46
8	95.31	0.31
			9	95.65	0.65
10	95.81	0.81
			11	95.49	0.49
12	95.82	0.82
			13	95.69	0.69
14	95.25	0.25
			15	95.96	0.96
16	96.01	1.01
			17	95.86	0.86
18	96.05	1.05
			19	96.15	1.15
20	95.71	0.71
			21	95.88	0.88
22	95.9	0.9
			23	95.33	0.33
24	95.79	0.79
			25	95.86	0.86
26	95.72	0.72
			27	95.83	0.83

In accordance with an embodiment of the present invention, there is provided a dimensional compensation method embodiment for additive manufactured parts, it being noted that the steps illustrated in the flow diagrams of the figures may be performed in a computer system, such as a set of computer-executable instructions, and that, although a logical order is illustrated in the flow diagrams, in some cases, the steps illustrated or described may be performed in an order other than that illustrated herein.

In this embodiment, a method for compensating the dimension of an additive manufactured part is provided, and fig. 2 is a flowchart of a method for compensating the dimension of an additive manufactured part according to an embodiment of the present invention, as shown in fig. 2, where the flowchart includes the following steps:

Step S201, a to-be-compensated workpiece stl model of the to-be-compensated additive manufacturing part is obtained, the to-be-compensated workpiece stl model is arranged in a forming space, and a plurality of initial coordinate values and a plurality of triangular surface vertex coordinate values of the to-be-compensated workpiece stl model are obtained based on a forming space coordinate system.

Wherein, the molding space represents the space for molding a workpiece (a part manufactured by additive to be compensated) in a molding equipment cabin in the selective laser sintering technology; the molding space coordinate system represents a Cartesian coordinate system established in a molding space defined by molding cabin hardware for molding a workpiece in a molding apparatus, and an origin of the coordinate system is at any point in the molding space.

Preferably, the origin of the coordinate system is located on the centerline of the vertical horizontal plane of the bounding box of the axis alignment of the molding space geometry defined by the molding volume hardware.

Optimally, the origin of the coordinate system is at the intersection of the centerline of the bounding box vertical horizontal plane aligned with the axis of the forming space geometry determined by the forming chamber hardware and the lowest horizontal plane of the forming chamber space for forming the workpiece.

Further, the workpiece stl model to be compensated may be a single stl model containing a plurality of testable distance dimension structures, or may be a plurality of stl models containing a plurality of testable distance dimension structures.

The testable distance dimension structure is a structure that can directly or indirectly obtain distance dimension data between two points by testing an actual molded workpiece with other testing tools such as a caliper, a three-coordinate system and a scanner.

Preferably, the testable distance dimension structure can be two parallel surface structures with two central point connecting lines perpendicular to the surface, and the dimension data between two points can be directly obtained by testing the actually molded workpiece through a vernier caliper.

Specifically, the coordinate values of the corresponding triangular surface vertexes of the model are recorded in the stl model of the workpiece to be compensated.

Further, the workpiece stl model to be compensated including the structure with the testable distance size is arranged in the forming space, and the initial coordinate values of the actual workpiece in any single coordinate axis direction, namely, the initial coordinate values of the points of the distance between the two points of the workpiece stl model to be compensated, namely, a plurality of initial coordinate values can be directly or indirectly obtained through the two points of the distance between the two points represented by the structure with the testable distance size.

Preferably, the total number of the acquired initial coordinate values is 8 or more.

Further, the distance between the closest point of the molding space near the cabin edge and the edge of the geometric space for molding the workpiece is less than or equal to 50mm.

Preferably, the distance between the closest point of the forming space near the cabin edge and the edge of the geometric space for forming the workpiece is smaller than or equal to 0mm.

The total number of the obtained points which are positioned in the forming space and are close to the edge of the cabin body is more than or equal to 6.

Further, a distance between a point of the obtained centerline in the direction of the corresponding coordinate axis of the bounding box, which is close to the axis alignment of the geometric space for molding the workpiece, and the centerline is 100mm or less.

Preferably, the obtained point near the centerline of the corresponding coordinate axis direction of the bounding box aligned with the axis of the geometric space for molding the workpiece is equal to 0mm from the centerline.

Further, the number of points of the obtained center line in the direction of the corresponding coordinate axis of the bounding box close to the axis alignment of the geometric space for molding the workpiece is 2 or more.

Step S202, obtaining the dimension error value of the additive manufactured part to be compensated through a preset processing method based on a preset dimension compensation function, a preset zoom center and a plurality of triangular surface vertex coordinate values.

The preset size compensation function is an initial scaling function used when the function relation between the size data and the space position is taken, and the initial scaling function can be:

(1) Constant function: p000=constant, m=0.

(2) Coordinate values of corresponding coordinate axes of triangular surface vertexes of the workpiece stl model to be compensated in a molding space coordinate system are used as independent variables, and scaling factors of the points in the directions of the corresponding coordinate axes are unitary linear functions or unitary multi-polynomial functions of dependent variables;

(3) The space coordinates of the triangular surface vertex of the workpiece stl model to be compensated in the forming space coordinate system are used as independent variables, and the scaling factor of the triangular surface vertex in the direction of the corresponding coordinate axis is a multi-element linear function or a multi-element multi-polynomial function of the dependent variables.

Further, the preset zoom center may be any point in the molding space coordinate system.

Preferably, the predetermined zoom center is on the centerline of the vertical horizontal plane of the bounding box with the axis of the forming space geometry defined by the forming chamber hardware.

Optimally, the preset zoom center is positioned on the intersection point of the central line of the vertical horizontal plane of the bounding box of the geometric body of the forming space determined by the forming cabin body hardware and the lowest horizontal plane of the space of the forming cabin body for forming the workpiece.

Specifically, the obtained preset size compensation function, the preset scaling center and the coordinate values of the vertexes of the triangular surfaces are combined to determine the size error value of the additive manufactured part to be compensated.

Step S203, a target data set is constructed based on a plurality of initial coordinate values, a preset size compensation function, a preset zoom center and a size error value.

The target data set may include a self-variable data set and a dependent variable data set, and is used for calculating each coefficient value of the size compensation function in the direction of the single coordinate axis, or is used for calculating the variation of each coefficient value of the size compensation function in the direction of the single coordinate axis.

Specifically, when the target data set is used to calculate the coefficient values of the individual coefficients of the size compensation function in the single coordinate axis direction, the calculation formulas of the individual independent variables in the independent variable data set and the individual dependent variables in the dependent variable data set are respectively shown in the following relations (1) and (2):

Wherein: n represents the number of distance sizes of the workpiece stl model to be compensated in the direction of a single coordinate axis; i, j, k represent the index value of an original coordinate x _ori,y_ori,z_ori of a triangular surface vertex of a workpiece stl model to be compensated in a forming space coordinate system in a preset size compensation function; a _nijk represents the value of the argument numbered nijk in the target dataset; x _nori1、y_nori1、z_nori1、x_nori2、y_nori2、z_nori2 represents the original coordinates of two points (point 1 and point 2) corresponding to the nth distance size in the molding space coordinate system, wherein the coordinate value of the corresponding coordinate axis of the point 2 is greater than or equal to the coordinate value of the corresponding coordinate axis of the point 1; c _nori1、c_nori2 represents coordinate values of the point 2 and the point 1 in the directions of the corresponding coordinate axes, respectively; c _base represents the coordinate of the preset zoom center in the direction of the corresponding coordinate axis; b _n represents the value of the dependent variable numbered n in the target dataset; m represents the control value of the index value of i, j, k; p _oldijk represents coefficient values corresponding to independent variables of i, j and k in x _ori,y_ori,z_ori index values in a size compensation function of a known workpiece stl model to be compensated; error _n represents an error value of the dimension in the direction of a single coordinate axis of the actual molded workpiece with the number n, namely a dimension error value; the values of m, i, j, k are 0,1, 2, 3 or 4, i+j+k.ltoreq.m.

Further, when the target data set is used to calculate the variation of each coefficient value of the size compensation function in the direction of a single coordinate axis, the calculation formula of the single argument in the self-variable data set is shown in the above relation (1), wherein the value of i, j, k is 0,1,2,3 or 4, and i+j+k is less than or equal to 0,1,2,3 or 4; the calculation formula of a single dependent variable in the dependent variable data set is shown in the following relation (3):

B_n＝-error_n (3)

step S204, determining a target size compensation function through a preset calculation method and an iterative optimization method based on the target data set.

Specifically, iterative optimization is performed through the constructed target data set until a target size compensation function for controlling the size accuracy in the whole molding space is obtained.

Step S205, based on the workpiece stl model to be compensated, the target additive manufactured part after size compensation is obtained through a target size compensation function and a selective laser sintering technology.

Specifically, the target workpiece stl model after size compensation can be obtained by processing the workpiece stl model to be compensated by the target size compensation function for controlling the size precision in the whole forming space finally obtained.

Further, the selective laser sintering technology is utilized to process the stl model of the target workpiece after size compensation, the target additive manufactured part after size compensation can be obtained, and the size precision of the part to be compensated manufactured by the selective laser sintering technology is improved.

According to the dimension compensation method for the additive manufactured part, position compensation is conducted on the triangular surface vertex coordinate values of the workpiece stl model to be compensated, which are arranged in the forming space, according to the preset dimension compensation function, dimension error values are obtained, and meanwhile, a target data set for calculating each coefficient value of the dimension compensation function in the direction of a single coordinate axis or for calculating the variation of each coefficient value of the dimension compensation function in the direction of the single coordinate axis is built by combining the dimension error values. Further, iterative optimization is carried out through the constructed target data set until a target size compensation function for controlling the size precision in the whole forming space is obtained, and finally the target size compensation function and the selective laser sintering technology are used for processing, so that the target additive manufactured part after size compensation can be obtained, and the size precision of the additive manufactured part to be compensated is improved.

In this embodiment, a method for compensating the dimension of an additive manufactured part is provided, and fig. 3 is a flowchart of a method for compensating the dimension of an additive manufactured part according to an embodiment of the present invention, as shown in fig. 3, where the flowchart includes the following steps:

Step S301, a to-be-compensated workpiece stl model of the to-be-compensated additive manufacturing part is obtained, the to-be-compensated workpiece stl model is arranged in a forming space, and a plurality of initial coordinate values and a plurality of triangular surface vertex coordinate values of the to-be-compensated workpiece stl model are obtained based on a forming space coordinate system. Please refer to step S201 in the embodiment shown in fig. 2 in detail, which is not described herein.

Step S302, based on a preset size compensation function, a preset zoom center and a plurality of triangular surface vertex coordinate values, obtaining a size error value of the additive manufactured part to be compensated through a preset processing method.

Specifically, the step S302 includes:

in step S3021, a scaling factor is calculated based on a preset size compensation function and a plurality of triangular surface vertex coordinate values.

Specifically, the scaling factor is calculated using the following relation (4):

Step S3022, scaling the workpiece stl model to be compensated by using the coordinate values of the vertices of the triangular surfaces, the preset scaling center and the scaling coefficient to obtain a scaled workpiece stl model to be compensated.

Specifically, scaling of the workpiece stl model to be compensated can be achieved by combining a plurality of triangular surface vertex coordinate values, a preset scaling center and scaling coefficients.

In some alternative embodiments, step S3022 includes:

step a1, calculating a distance value between each triangular surface vertex and a preset scaling center based on coordinate values of the plurality of triangular surface vertices and the preset scaling center.

And a step a2, determining a plurality of triangular surface vertex coordinate values of the scaled workpiece stl model to be compensated based on a plurality of distance values, a preset scaling center and scaling coefficients.

And a step a3 of determining the scaled workpiece stl model to be compensated based on the coordinate values of the vertexes of the triangular surfaces of the scaled workpiece stl model to be compensated.

Specifically, the scaled triangle face vertex coordinate values are calculated using the following relation (5):

Wherein: c' represents coordinate values in the directions of corresponding coordinate axes after the triangular surface vertexes of the stl model of the workpiece to be compensated are calculated according to the size compensation function in the directions of the corresponding coordinate axes, namely scaled triangular surface vertex coordinate values; c _ori represents coordinate values of the triangular surface vertex of the stl model of the workpiece to be compensated in the direction of the corresponding coordinate axis, namely coordinate values of the triangular surface vertex; c _ori-c_base represents a distance value.

Step S3023, processing the scaled workpiece stl model to be compensated by using the selective laser sintering technology and obtaining the dimensional error value.

Specifically, sintering treatment is carried out on the scaled workpiece stl model to be compensated by utilizing a selective laser sintering technology.

Further, cleaning, testing and evaluating the additive manufactured part to be compensated corresponding to the stl model of the sintered workpiece to be compensated to obtain a corresponding dimension error value error _n, wherein the dimension error value error is shown in the following relation (6):

error_n＝Actual_n-Normal_n (6)

Wherein: actual _n represents the measured distance dimension in the direction of the corresponding coordinate axis with the number n; normal _n represents the drawing dimensions of the workpiece stl model to be compensated in the direction of the corresponding coordinate axis with the number n.

Step S303, constructing a target data set based on a plurality of initial coordinate values, a preset size compensation function, a preset zoom center and a size error value. Please refer to step S203 in the embodiment shown in fig. 2 in detail, which is not described herein.

Step S304, determining a target size compensation function through a preset calculation method and an iterative optimization method based on the target data set. Please refer to step S204 in the embodiment shown in fig. 2 in detail, which is not described herein.

And step S305, processing by a target size compensation function and a selective laser sintering technology based on the workpiece stl model to be compensated to obtain the target additive manufactured part after size compensation. Please refer to step S205 in the embodiment shown in fig. 2 in detail, which is not described herein.

According to the dimension compensation method for the additive manufactured part, the dimension error value of the additive manufactured part to be compensated can be obtained by scaling the workpiece stl model to be compensated through the calculated scaling factor and combining the preset scaling center and the obtained triangular surface vertex coordinate values of the workpiece stl model to be compensated, and further by sintering treatment through a selective laser sintering technology. And simultaneously, combining the size error values to construct a target data set for calculating each coefficient value of the size compensation function in the direction of the single coordinate axis or for calculating the variation of each coefficient value of the size compensation function in the direction of the single coordinate axis. Further, iterative optimization is carried out through the constructed target data set until a target size compensation function for controlling the size precision in the whole forming space is obtained, and finally the target size compensation function and the selective laser sintering technology are used for processing, so that the target additive manufactured part after size compensation can be obtained, and the size precision of the additive manufactured part to be compensated is improved.

In this embodiment, a method for compensating the dimension of an additive manufactured part is provided, and fig. 4 is a flowchart of a method for compensating the dimension of an additive manufactured part according to an embodiment of the present invention, as shown in fig. 4, where the flowchart includes the following steps:

Step S401, a to-be-compensated workpiece stl model of the to-be-compensated additive manufacturing part is obtained, the to-be-compensated workpiece stl model is arranged in a forming space, and a plurality of initial coordinate values and a plurality of triangular surface vertex coordinate values of the to-be-compensated workpiece stl model are obtained based on a forming space coordinate system. Please refer to step S201 in the embodiment shown in fig. 2 in detail, which is not described herein.

Step S402, obtaining the dimension error value of the additive manufactured part to be compensated through a preset processing method based on a preset dimension compensation function, a preset zoom center and a plurality of triangular surface vertex coordinate values. Please refer to step S302 in the embodiment shown in fig. 3 in detail, which is not described herein.

Step S403, constructing a target data set based on the plurality of initial coordinate values, the preset size compensation function, the preset zoom center and the size error value. Please refer to step S203 in the embodiment shown in fig. 2 in detail, which is not described herein.

Step S404, determining a target size compensation function through a preset calculation method and an iterative optimization method based on the target data set.

Specifically, the step S404 includes:

step S4041, a plurality of function coefficient values are calculated based on the target data set.

In particular, a plurality of coefficient values for the corresponding size compensation function may be calculated from the constructed target data set.

In some alternative embodiments, step S4041 includes:

Step b1, constructing a first equation set based on the target data set.

And b2, solving the first equation group to obtain a plurality of function coefficient values.

The first equation set is used for representing the corresponding relation between the target data set and the function coefficient value.

Specifically, when the target data set is used to calculate the coefficient values of the size compensation function in the single coordinate axis direction, a first equation set having the sub-number equal to the number of distance sizes obtained in the corresponding coordinate axis direction of the actually molded workpiece is constructed, as shown in the following relational expression (7):

Wherein: p _newijk represents the target coefficient value corresponding to the independent variable whose x _ori,y_ori,z_ori index value is i, j and k in the size compensation function in the direction of the corresponding coordinate axis to be solved.

Further, each coefficient value of the target size scaling function in the corresponding coordinate axis direction can be obtained by solving the P _newijk.

The solution method may include direct solution, matrix decomposition, iteration, interpolation, fitting, geometric algebra, geometric calculation, and methods based on other mathematical principles, which are not specifically limited in the embodiments of the present invention.

In some optional embodiments, the step S4041 further includes:

And b3, constructing a second equation set based on the target data set.

And b4, solving the second equation set to obtain a plurality of variable quantities.

And b5, calculating a plurality of function coefficient values based on the plurality of variation amounts.

The second equation set is used for representing the corresponding relation between the target data set and the variation of the function coefficient value.

Specifically, when the target data set is used to calculate the variation of each coefficient value of the size compensation function in the single coordinate axis direction, a second equation set having the sub-number equal to the number of distance sizes obtained in the corresponding coordinate axis direction of the actually molded workpiece is constructed, as shown in the following relational expression (8):

Wherein: Δp _ijk represents the variation of the target coefficient value corresponding to the independent variable whose x _ori,y_ori,z_ori index value is i, j, k in the size compensation function in the direction of the corresponding coordinate axis to be solved.

Further, the variation of the target size scaling function in the single coordinate axis direction relative to the coefficient values of the known input size compensation function can be obtained by solving the delta P _ijk.

Further, the coefficient values of the target size scaling function are calculated using the following relation (9):

P_newijk＝ΔP_ijk+P_oldijk(9)

Further, in the two solving processes, 21. The value of the target size scaling function assignment term coefficient may be preset to implement the custom target size scaling function solving, including, but not limited to, setting the coefficient of the term assignment containing the argument stl file triangle surface vertex in the original horizontal direction coordinate in the forming space coordinate system to 0, further, the obtained target size scaling function is related only to the original height direction coordinate of stl file triangle surface vertex in the forming space.

Step S4042, determining an initial size compensation function based on the plurality of function coefficient values.

Specifically, a corresponding size compensation function may be determined based on the obtained plurality of function coefficient values.

Step S4043, based on the initial size compensation function, returning to the step of obtaining the stl model of the workpiece to be compensated of the additive manufacturing part to be compensated, and repeating iteration until the size precision of the stl model of the workpiece to be compensated reaches the preset requirement, thereby obtaining the target size compensation function.

Specifically, the steps S401 to S404 are repeated, and the obtained initial size compensation function is used as the preset size compensation function of step S402, until the size precision of the additive manufactured part to be compensated corresponding to the workpiece stl model to be compensated for testing the size reaches the preset requirement, and the final size compensation function is determined.

Step S405, based on the workpiece stl model to be compensated, the target additive manufactured part after size compensation is obtained through a target size compensation function and a selective laser sintering technology. Please refer to step S205 in the embodiment shown in fig. 2 in detail, which is not described herein.

According to the dimension compensation method for the additive manufactured part, position compensation is conducted on the triangular surface vertex coordinate values of the workpiece stl model to be compensated, which are arranged in the forming space, according to the preset dimension compensation function, dimension error values of the additive manufactured part to be compensated are obtained, and meanwhile, a target data set for calculating various coefficient values of the dimension compensation function in the direction of a single coordinate axis or for calculating the variation of various coefficient values of the dimension compensation function in the direction of the single coordinate axis is built by combining the dimension error values. Further, coefficient values of the corresponding size compensation functions can be calculated through the constructed target data set, the target size compensation functions for controlling the size precision in the whole forming space can be obtained through iterative optimization, finally, the target size compensation functions and the selective laser sintering technology are used for processing, the target additive manufactured parts after size compensation can be obtained, and the size precision of the additive manufactured parts to be compensated is improved.

In one example, as shown in FIG. 5, a method of dimension compensation for a part data model is provided, comprising the steps of:

step 1: arranging a workpiece stl model containing a structure with a testable distance size in a molding space, and recording initial coordinate values of two points of the distance between the two points represented by the structure with the testable distance size in a molding space coordinate system;

Step 2: calculating corresponding scaling coefficients according to the input size compensation function and the vertex coordinates of each triangular surface of the workpiece model stl file in the step 1, and performing scaling calculation on the model stl according to a preset scaling center to obtain a scaled workpiece stl file;

step 3: selectively laser sintering the scaled workpiece stl file, cleaning the workpiece, and then testing and evaluating the dimensional error of the workpiece;

Step 4: constructing a data set for calculating each coefficient value of the target size scaling function according to the initial coordinate value recorded in the step 1, the size compensation function input in the step 2, the preset scaling center and the actually measured size error value of the workpiece obtained in the step 3;

step 5: calculating each coefficient value of the target size scaling function according to the data set obtained in the step 4, and obtaining a new size compensation function;

step 6: repeating the steps 1-5, taking the new size compensation function obtained in the step 5 as the input size compensation function of the step 2 until the size precision of the workpiece for testing the size meets the requirement, and determining the final size compensation function;

step 7: and processing the conventional workpiece by using the obtained size compensation function.

According to the dimension compensation method of the part data model, position compensation is conducted on the triangular surface vertex coordinates of any workpiece in a forming space according to a dimension compensation function, calibration workpieces with proper test dimensions are sintered to obtain differences between actual measurement dimensions and drawing dimensions of workpieces at different positions in the whole forming space, coefficient values of a dimension compensation function relation are calculated in a fitting mode, the stl model of the dimension calibration workpiece is compensated by the obtained dimension compensation function with new coefficient values, the process is repeated until dimension precision of the dimension calibration workpiece meets requirements, and finally a compensation function for controlling dimension precision in the whole forming space is obtained and is used for processing conventional workpieces, and dimension precision of the workpieces is improved.

Further, a specific embodiment is provided based on the dimension compensation method of the part data model provided in the above example, including:

step 01: as shown in fig. 6, a single rectangular workpiece with a size of 6.5mm by 100mm is designed, the structure for testing the distance is two parallel rectangular surfaces with a distance length equal to 100mm, two points representing the distance between two points are the center points of the two parallel rectangular surfaces, and the output is stl format files, and the total number is 860.

Further, stl files of 860 cuboids are arranged in a molding space with a size of 350mm by 530mm, as shown in fig. 7, a cartesian coordinate system is established in a molding space defined by molding cabin hardware for molding a workpiece in the molding apparatus, and an origin of the coordinate system is located at an intersection point of a center line of a vertical horizontal plane of a bounding box aligned with an axis of a molding space geometry defined by the molding cabin hardware and a lowest horizontal plane of a space for molding the workpiece by the molding cabin.

Further, a pair of parallel rectangular surfaces for testing distances in each cuboid stl are parallel to the horizontal plane of the forming space, the z coordinate of a center point 2 is larger than the z coordinate of a center point 1, the z coordinate is used for directly obtaining the distance between the center points of two parallel rectangular surfaces with the actual workpiece drawing distance of 100mm in the z axis direction of a forming space coordinate system, the total number of points is 1720, the number of workpieces stl which are positioned in the forming space and are close to the edges of a cabin is 245, the distance between the center point of the rectangular surface of a structure for testing the actual workpiece distance and the nearest geometric space edge for forming a workpiece is smaller than 1mm, and the total number of center points is 490; the number of rectangular parallelepiped workpieces stl near the axis-aligned bounding box of the geometric space for forming the workpiece is 5, the distance from the center point of the rectangular face of the structure for testing the actual workpiece distance to the axis-aligned bounding box of the geometric space for forming the workpiece is equal to 0mm, the number of center points is 10 in total, as shown in fig. 8A and 8B, which are top view and front view of the placement position of the rectangular parallelepiped workpieces stl in the forming space, respectively.

Further, original coordinate values of center points of 1720 rectangular faces applied to the test of the distance between two points in the molding space coordinate system for all 860 rectangular stls are recorded as shown in the following table 2, wherein,

Table 2, cuboid stl, original coordinate values in the molding space coordinate system for the center point of the rectangular surface applied to test the distance between two points

Number n	x_nori1,x_nori2	y_nori1,y_nori2	z_nori1	z_nori2
					1	-174.39	-174.401	5.324	105.324
2	-164.65	-174.401	5.324	105.324
					3	-148.91	-174.401	5.324	105.324
4	-124.17	-174.401	5.324	105.324
					5	-90.431	-174.401	5.324	105.324
6	-47.691	-174.401	5.324	105.324
					7	0	-174.401	5.324	105.324
8	47.691	-174.401	5.324	105.324
					9	90.431	-174.401	5.324	105.324
10	124.17	-174.401	5.324	105.324
					……	……	……	……	……
856	90.431	174.401	428.676	528.676
					857	124.17	174.401	428.676	528.676
858	148.91	174.401	428.676	528.676
					859	164.65	174.401	428.676	528.676
860	174.39	174.401	428.676	528.676

Step 02: stl of 860 cuboids is scaled, and a preset z-axis size compensation function is input as shown in the following relation (10):

Wherein: x _ori,y_ori,z_ori represents the original coordinates of all triangular surface vertices of 860 workpiece stl files in the molding space coordinate system; The scaling factor in the z coordinate axis direction calculated by the size compensation function at the triangular surface vertex of the corresponding stl file at coordinate x _ori,y_ori,z_ori in the molding space coordinate system is represented.

Further, in the scaling calculation, the predetermined scaling center is located at the intersection point of the center line of the vertical horizontal plane of the bounding box of the geometric body of the forming space determined by the forming cabin body hardware and the lowest horizontal plane of the space of the forming cabin body for forming the workpiece, that is, the origin of the coordinate system, and the corresponding coordinate value is (0, 0).

Further, the distances from the z coordinate positions of each point of the triangular surface of 860 stl files in the forming space coordinate system to the preset scaling center in the z coordinate axis direction are calculated, the sum of the product and the distance of the scaling coefficient calculated by the size compensation function in the z coordinate axis direction of the distance and the corresponding point is taken as the coordinate value of the coordinate point of the triangular surface of the final stl file in the z coordinate axis direction as a new coordinate value after scaling, and the calculation formula is shown in the following relational expression (11):

Wherein: and z' represents coordinate values of the stl file triangular surface vertex in the z coordinate axis direction after calculation according to the z coordinate axis direction size compensation function.

Further, after the scaling calculation is completed, the scaled cuboid workpiece stl file is output.

Step 03: and (3) selectively sintering the scaled cuboid workpieces stl by laser, testing the distance between two parallel rectangular surface workpieces with the distance dimension by using a vernier caliper after cleaning the workpieces, calculating errors, and adopting a calculation formula as shown in the following relational expression (12):

error_n＝Actual_n-100 (12)

Further, the actual measurement distance dimension and error value of the actual molded rectangular stl workpiece are shown in fig. 9.

Further, specific values of the actual measurement distance dimension and the error value of the actual molded rectangular stl workpiece are shown in table 3 below:

TABLE 3 actually measured distance dimension and error value of actual formed cuboid stl workpiece

Sequence number	Actual_n	error_n
			1	100.28	0.28
2	100.2	0.2
			3	100.14	0.14
4	100.12	0.12
			5	100.1	0.1
6	100.16	0.16
			7	100.18	0.18
8	100.22	0.22
			9	100.26	0.26
10	100.27	0.27
			……	……	……
856	100.76	0.76
			857	100.76	0.76
858	100.78	0.78
			859	100.8	0.8
860	100.88	0.88

Further, 860 error data total, maximum positive error 1.24mm, maximum negative error-0.26 mm, error number ratio within + -0.3 mm error range 26.63%, error number ratio beyond + -0.3 mm error range 73.37%, assessed as requiring further calibration.

Step 04: constructing a data set for the variable quantity of each coefficient value of the target size scaling function in the z coordinate axis direction according to the initial coordinate value recorded in the step 01, the size compensation function input in the step 02, the preset scaling center and the actually measured size error value of the workpiece obtained in the step 03, wherein the calculation formula of a single independent variable in the self-variable data set is shown in the following relational expression (13):

further, the calculation formula of the individual dependent variables in the dependent variable data set is shown in the above-described relation (3).

Step 05: constructing a system of 860 sub-equations from the data set of the self-variable values and the factor-variable values constructed in step 04 for calculating the variation of the coefficient values of the target size scaling function, as shown in the following relation (14)

Further, the expression is expressed as the following relational expression (15) in the form of a matrix:

further, the following relational expression (15) is obtained by matrix decomposition:

wherein Δp ₀₀₀、ΔP₀₀₁、ΔP₀₀₂、……、ΔP₂₁₀、ΔP₃₀₀ represents the variation value of the target coefficient of the 20 z-direction size compensation function to be solved relative to the original input coefficient.

Further, the change value of the target coefficient of the 20 z-direction size compensation function relative to the original input coefficient is obtained through solving, and each coefficient value of the target size scaling function is obtained through calculation according to the original z-coordinate direction size compensation function input in the step 02, wherein the coefficient value is shown in the following relation (17):

step 06: step 06, repeating steps 01-05, arranging stl files of 860 cuboids in a forming space, keeping the initial positions of all stls the same as those of the first cycle, recording the original coordinate values of the center points of 1720 rectangular surfaces corresponding to the distance between the two points to be tested in the forming space coordinate system, scaling the stls of 860 cuboids, and using a target size scaling function obtained in the first cycle as a preset z-axis size compensation function, wherein the following relation (18) shows:

Wherein, P _ijk represents coefficient values corresponding to independent variables of which x _ori,y_ori,z_ori index values are i, j, and k in the preset size compensation function, respectively, as shown in the following relation (19):

/>

Further, the predetermined scaling center is maintained as the origin of the coordinate system at the time of scaling calculation, the corresponding coordinate values are (0, 0), and scaling calculation is performed again on 860 pieces of workpiece stl according to the above-mentioned relational expression (11).

Further, outputting the scaled cuboid workpiece stl file, re-selectively sintering by laser, cleaning, testing the distance between two parallel rectangular workpieces with different distance sizes, and calculating the error according to the relation (12).

The actual measured distance and error values of the cuboid stl workpiece actually formed in the second cycle are shown in fig. 10.

Further, specific values of the actual measured distance dimension and the error value of the actual molded rectangular stl workpiece in the second cycle are shown in table 4 below:

table 4 actually measured distance dimension and error value of the cuboid stl workpiece formed in the second cycle

Further, 860 pieces of error data total, 0.3mm maximum positive error, 0.29mm maximum negative error, 100% error count within the error range of + -0.3 mm, 0% error count within the error range of + -0.3 mm, and no further calibration was evaluated as necessary, and the size calibration step was ended.

Further, the conventional work piece is processed by using the obtained size compensation function, the size precision is improved, and the size error of all conventional work pieces at any position in the forming space is within +/-0.3 mm.

Further, the positions of the work pieces in the forming space and the measured dimensional errors when the conventional work pieces were processed using the obtained dimensional compensation function are shown in table 5 below:

TABLE 5 position of workpiece in forming space and measured dimensional error when processing conventional workpiece using the obtained dimensional compensation function

Numbering device	Measured dimension mm	Error mm
			1	95.06	0.06
2	95.25	0.25
			3	94.77	-0.23
4	95.22	0.22
			5	95.26	0.26
6	95.13	0.13
			7	94.99	-0.01
8	95.25	0.25
			9	95.13	0.13
10	95.12	0.12
			11	94.99	-0.01
12	95	0
			13	95.3	0.3
14	94.93	-0.07
			15	95.2	0.2
16	95.07	0.07
			17	95.23	0.23
18	95.04	0.04
			19	94.93	-0.07
20	95.04	0.04
			21	94.88	-0.12
22	95.2	0.2
			23	95.06	0.06
24	95.18	0.18
			25	95.12	0.12
26	95.28	0.28
			27	95.01	0.01

In this embodiment, a size compensation device for an additive manufactured part is further provided, and the size compensation device is used to implement the foregoing embodiments and preferred embodiments, and is not described again. As used below, the term "module" may be a combination of software and/or hardware that implements a predetermined function. While the means described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware, is also possible and contemplated.

The present embodiment provides a dimension compensation device for an additive manufactured part, as shown in fig. 11, including:

the arrangement and acquisition module 501 is configured to arrange the stl model of the workpiece to be compensated in a forming space, and acquire a plurality of initial coordinate values and a plurality of triangular vertex coordinate values of the stl model of the workpiece to be compensated based on a forming space coordinate system, where the forming space represents a space for forming the workpiece in a forming equipment cabin in a selective laser sintering technology, the forming space coordinate system is represented as a cartesian coordinate system established in the forming space, and an origin of the coordinate system is located at any point in the forming space.

The processing module 502 is configured to obtain a dimension error value of the additive manufactured part to be compensated through a preset processing method based on a preset dimension compensation function, a preset zoom center and a plurality of triangular surface vertex coordinate values.

A construction module 503, configured to construct a target data set based on a plurality of initial coordinate values, a preset size compensation function, a preset scaling center and a size error value, where the target data set is used to calculate each coefficient value of the size compensation function in a single coordinate axis direction, or is used to calculate a variation of each coefficient value of the size compensation function in the single coordinate axis direction.

A determining module 504, configured to determine a target size compensation function based on the target data set through a preset calculation method and an iterative optimization method.

The processing module 505 is configured to obtain a target additive manufactured part after size compensation through processing by a target size compensation function and a selective laser sintering technology based on the stl model of the workpiece to be compensated.

In some alternative embodiments, the processing module 502 includes:

And the first computing sub-module is used for computing a scaling coefficient based on the preset size compensation function and the coordinate values of the plurality of triangular surface vertexes.

And the scaling sub-module is used for scaling the workpiece stl model to be compensated by utilizing the coordinate values of the triangular surface vertexes, the preset scaling center and the scaling coefficient to obtain the scaled workpiece stl model to be compensated.

And the processing and acquiring sub-module is used for processing the scaled workpiece stl model to be compensated by utilizing the selective laser sintering technology and acquiring a size error value.

In some alternative embodiments, the scaling submodule includes:

the first calculating unit is used for calculating the distance value between each triangular surface vertex and the preset scaling center based on the coordinate values of the triangular surface vertices and the preset scaling center.

The first determining unit is used for determining a plurality of triangular surface vertex coordinate values of the scaled workpiece stl model to be compensated based on a plurality of distance values, a preset scaling center and scaling coefficients.

And the second determining unit is used for determining the scaled workpiece stl model to be compensated based on the coordinate values of the vertexes of the triangular surfaces of the scaled workpiece stl model to be compensated.

In some alternative embodiments, the determining module 504 includes:

A second calculation sub-module for calculating a plurality of function coefficient values based on the target dataset.

A determination submodule determines an initial size compensation function based on a plurality of function coefficient values.

And the repeating submodule is used for returning to the step of acquiring the stl model of the workpiece to be compensated of the additive manufacturing part to be compensated based on the initial size compensation function, and repeating iteration until the size precision of the stl model of the workpiece to be compensated reaches the preset requirement, so as to obtain the target size compensation function.

In some alternative embodiments, the second computing sub-module includes:

the first construction unit is used for constructing a first equation set based on the target data set, and the first equation set is used for representing the corresponding relation between the target data set and the function coefficient value.

And the first solving unit is used for solving the first equation set to obtain a plurality of function coefficient values.

In some alternative embodiments, the second computing sub-module further comprises:

and the second construction unit is used for constructing a second equation set based on the target data set, wherein the second equation set is used for representing the corresponding relation between the target data set and the variation of the function coefficient value.

And the second solving unit is used for solving the second equation set to obtain a plurality of variation quantities.

And a second calculation unit configured to calculate a plurality of function coefficient values based on the plurality of variation amounts.

In some alternative embodiments, the first computing sub-module includes:

A third calculation unit for calculating a scaling factor by a relation of:

Further functional descriptions of the above respective modules and units are the same as those of the above corresponding embodiments, and are not repeated here.

The dimensional compensation device of the additive manufactured part in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC (Application SPECIFIC INTEGRATED Circuit) Circuit, a processor and a memory that execute one or more software or firmware programs, and/or other devices that can provide the above functions.

The embodiment of the invention also provides computer equipment, which is provided with the dimension compensation device of the additive manufactured part shown in the figure 11.

Referring to fig. 12, fig. 12 is a schematic structural diagram of a computer device according to an alternative embodiment of the present invention, as shown in fig. 12, the computer device includes: one or more processors 10, memory 20, and interfaces for connecting the various components, including high-speed interfaces and low-speed interfaces. The various components are communicatively coupled to each other using different buses and may be mounted on a common motherboard or in other manners as desired. The processor may process instructions executing within the computer device, including instructions stored in or on memory to display graphical information of the GUI on an external input/output device, such as a display device coupled to the interface. In some alternative embodiments, multiple processors and/or multiple buses may be used, if desired, along with multiple memories and multiple memories. Also, multiple computer devices may be connected, each providing a portion of the necessary operations (e.g., as a server array, a set of blade servers, or a multiprocessor system). One processor 10 is illustrated in fig. 12.

The processor 10 may be a central processor, a network processor, or a combination thereof. The processor 10 may further include a hardware chip, among others. The hardware chip may be an application specific integrated circuit, a programmable logic device, or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general-purpose array logic, or any combination thereof.

Wherein the memory 20 stores instructions executable by the at least one processor 10 to cause the at least one processor 10 to perform a method for implementing the embodiments described above.

The memory 20 may include a storage program area that may store an operating system, at least one application program required for functions, and a storage data area; the storage data area may store data created according to the use of the computer device, etc. In addition, the memory 20 may include high-speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, flash memory device, or other non-transitory solid-state storage device. In some alternative embodiments, memory 20 may optionally include memory located remotely from processor 10, which may be connected to the computer device via a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.

Memory 20 may include volatile memory, such as random access memory; the memory may also include non-volatile memory, such as flash memory, hard disk, or solid state disk; the memory 20 may also comprise a combination of the above types of memories.

The computer device also includes a communication interface 30 for the computer device to communicate with other devices or communication networks.

The embodiments of the present invention also provide a computer readable storage medium, and the method according to the embodiments of the present invention described above may be implemented in hardware, firmware, or as a computer code which may be recorded on a storage medium, or as original stored in a remote storage medium or a non-transitory machine readable storage medium downloaded through a network and to be stored in a local storage medium, so that the method described herein may be stored on such software process on a storage medium using a general purpose computer, a special purpose processor, or programmable or special purpose hardware. The storage medium can be a magnetic disk, an optical disk, a read-only memory, a random access memory, a flash memory, a hard disk, a solid state disk or the like; further, the storage medium may also comprise a combination of memories of the kind described above. It will be appreciated that a computer, processor, microprocessor controller or programmable hardware includes a storage element that can store or receive software or computer code that, when accessed and executed by the computer, processor or hardware, implements the methods illustrated by the above embodiments.

Although embodiments of the present invention have been described in connection with the accompanying drawings, various modifications and variations may be made by those skilled in the art without departing from the spirit and scope of the invention, and such modifications and variations fall within the scope of the invention as defined by the appended claims.

Claims

1. A method of dimensional compensation of an additively manufactured part, the method comprising:

acquiring a workpiece stl model to be compensated of an additive manufacturing part to be compensated, arranging the workpiece stl model to be compensated in a forming space, and acquiring a plurality of initial coordinate values and a plurality of triangular vertex coordinate values of the workpiece stl model to be compensated based on a forming space coordinate system, wherein the forming space represents a space for forming a workpiece in a forming equipment cabin in a selective laser sintering technology, and the forming space coordinate system is represented as a Cartesian coordinate system established in the forming space, and the origin of the coordinate system is located at any point in the forming space;

obtaining a dimension error value of the additive manufactured part to be compensated through a preset processing method based on a preset dimension compensation function, a preset scaling center and the vertex coordinate values of the triangular faces;

Constructing a target data set based on the plurality of initial coordinate values, the preset size compensation function, the preset scaling center and the size error value, wherein the target data set is used for calculating each coefficient value of the size compensation function in the direction of a single coordinate axis or calculating the variation of each coefficient value of the size compensation function in the direction of the single coordinate axis;

Determining a target size compensation function through a preset calculation method and an iterative optimization method based on the target data set;

And processing the workpiece stl model to be compensated through the target size compensation function and the selective laser sintering technology to obtain the target additive manufactured part after size compensation.

2. The method of claim 1, wherein obtaining the dimensional error value of the additive manufactured part to be compensated via a preset processing method based on a preset dimensional compensation function, a preset scaling center, and the plurality of triangular surface vertex coordinate values comprises:

Calculating a scaling factor based on the preset size compensation function and the coordinate values of the plurality of triangular surface vertexes;

scaling the workpiece stl model to be compensated by utilizing the triangular plane vertex coordinate values, the preset scaling center and the scaling coefficient to obtain a scaled workpiece stl model to be compensated;

and processing the scaled workpiece stl model to be compensated by using a selective laser sintering technology and obtaining the size error value.

3. The method according to claim 2, wherein scaling the workpiece stl model to be compensated using the plurality of triangular face vertex coordinate values, the preset scaling center, and the scaling coefficient, to obtain the scaled workpiece stl model to be compensated, comprises:

Calculating a distance value between each triangular surface vertex and the preset scaling center based on the coordinate values of the triangular surface vertices and the preset scaling center;

Determining a plurality of triangular surface vertex coordinate values of the scaled workpiece stl model to be compensated based on a plurality of distance values, the preset scaling center and the scaling coefficient;

And determining the scaled workpiece stl model to be compensated based on the coordinate values of the triangular surface vertexes of the scaled workpiece stl model to be compensated.

4. The method of claim 1, wherein determining a target size compensation function based on the target data set via a preset calculation method and an iterative optimization method comprises:

Calculating a plurality of function coefficient values based on the target dataset;

determining an initial size compensation function based on the plurality of function coefficient values;

and returning to the step of obtaining the stl model of the workpiece to be compensated of the additive manufacturing part to be compensated based on the initial size compensation function, and repeatedly iterating until the size precision of the stl model of the workpiece to be compensated reaches a preset requirement, so as to obtain the target size compensation function.

5. The method of claim 4, wherein calculating a plurality of function coefficient values based on the target dataset comprises:

Constructing a first equation set based on the target data set, wherein the first equation set is used for representing the corresponding relation between the target data set and the function coefficient value;

and solving the first equation set to obtain the plurality of function coefficient values.

6. The method of claim 4, wherein calculating a plurality of function coefficient values based on the target dataset further comprises:

Constructing a second equation set based on the target data set, wherein the second equation set is used for representing the corresponding relation between the target data set and the variation of the function coefficient value;

solving the second equation set to obtain a plurality of variable quantities;

the plurality of function coefficient values are calculated based on the plurality of variation amounts.

7. The method of claim 2, wherein calculating a scaling factor based on the preset size compensation function and the plurality of triangular face vertex coordinate values comprises: the scaling factor is calculated by the relationship:

Wherein: x _ori,y_ori,z_ori represents an original coordinate value of a triangular vertex of the stl model of the workpiece to be compensated in the molding space coordinate system; Representing a scaling factor in a single coordinate axis direction calculated by a preset size compensation function at a triangular surface vertex of a workpiece stl model to be compensated with a coordinate x _ori,y_ori,z_ori in the molding space coordinate system; i, j, k represent the index value of an original coordinate x _ori,y_ori,z_ori of a triangular surface vertex of a workpiece stl model to be compensated in a forming space coordinate system in a preset size compensation function; m represents the control value of the index value of i, j, k; p _ijk represents the coefficient value corresponding to the independent variable of which the x _ori,y_ori,z_ori index value is i, j and k in the preset size compensation function respectively; the values of m, i, j, k are 0, 1,2,3 or 4, i+j+k.ltoreq.m.

8. A size compensation device for an additively manufactured part, the device comprising:

The arrangement and acquisition module is used for acquiring a to-be-compensated workpiece stl model of the to-be-compensated additive manufacturing part, arranging the to-be-compensated workpiece stl model in a forming space, and acquiring a plurality of initial coordinate values and a plurality of triangular surface vertex coordinate values of the to-be-compensated workpiece stl model based on a forming space coordinate system, wherein the forming space represents a space for forming a workpiece in a forming equipment cabin in a selective laser sintering technology, and the forming space coordinate system is represented as a Cartesian coordinate system established in the forming space, and the origin of the coordinate system is positioned at any point in the forming space;

The processing module is used for obtaining the dimension error value of the additive manufactured part to be compensated through a preset processing method based on a preset dimension compensation function, a preset zoom center and the coordinate values of the triangular surface vertexes;

The construction module is used for constructing a target data set based on the initial coordinate values, the preset size compensation function, the preset scaling center and the size error value, wherein the target data set is used for calculating each coefficient value of the size compensation function in the direction of a single coordinate axis or calculating the variation of each coefficient value of the size compensation function in the direction of the single coordinate axis;

The determining module is used for determining a target size compensation function based on the target data set through a preset calculation method and an iterative optimization method;

and the processing module is used for processing the workpiece stl model to be compensated through the target size compensation function and the selective laser sintering technology to obtain the target additive manufactured part after size compensation.

9. A computer device, comprising:

a memory and a processor in communication with each other, the memory having stored therein computer instructions that, upon execution, perform the method of size compensation of an additive manufactured part of any one of claims 1 to 7.

10. A computer-readable storage medium having stored thereon computer instructions for causing a computer to perform the method of size compensation of an additive manufactured part according to any one of claims 1 to 7.