CN117841352A - Fused deposition 3D printing method considering regional performance - Google Patents

Abstract

The invention discloses a fused deposition 3D printing method considering regional performance, which is realized through an inner and outer region segmentation and layering algorithm and an inner region segmentation and variable density filling algorithm, wherein the inner and outer region segmentation and layering algorithm is used for dividing a printing model into an outer contour and an inner region, and an adaptive layering algorithm is used for the outer contour so as to ensure the side printing precision, and the upper surface and the lower surface adopt minimum line width printing to improve the precision of the upper surface and the lower surface; the internal area is printed by using the superposition thickness of the self-adaptive layering algorithm, so that the printing efficiency is improved. The internal region segmentation and variable density filling algorithm is to segment the region according to the stress distribution of the printing model, and then to carry out density filling according to the stress of the region, so as to improve the stress distribution of the printing part, reduce the maximum stress of the printing model and improve the mechanical property of the printing part.

Description

Fused deposition 3D printing method considering regional performance

Technical Field

The invention belongs to the technical field of 3D printing, and particularly relates to a fused deposition 3D printing method considering regional performance.

Background

3D printing technology has been developed for more than thirty years since birth, and many 3D printing technologies at this stage are mainly classified into selective laser fusion forming, selective laser sintering forming, laser direct sintering technology, electron beam melting technology, fused deposition forming, selective thermal sintering, and the like. The fused deposition modeling technology has the most rapid development and wide application range, is the most printing technology used by the current 3D printer, but is undeniable that the fused deposition modeling technology has a plurality of defects such as low precision, low strength of printed parts and the like.

First, the step effect is an unavoidable disadvantage due to the limitation of the molding mode of the fused deposition modeling technique, which greatly affects the precision of the printed matter, so reducing the step effect is one of the key problems of the current research. Secondly, research shows that the strength of the printed piece is related to the filling density and the filling structure in the printed piece, the greater the filling density is, the higher the strength of the printed piece is, but the more consumables are used, so that the improvement of the mechanical property of the printed piece under the condition of not increasing the consumables is the key point of the current research.

At present, in the aspect of improving the precision, the self-adaptive layering is mainly used for replacing the traditional equal-thickness layering, so that the influence of the step effect on the precision is reduced, the dimensional deviation generated by the equal-thickness layering is eliminated, but if the initial layer thickness and the final layer thickness are too large, the printed line width is also large, and the precision of the upper surface and the lower surface is also reduced; in the aspect of improving mechanical properties, the mechanical properties of a printed product are improved mainly by changing the internal filling shape, but the problems of overlarge stress distribution difference and overlarge local stress still exist for an irregular plate, and a fused deposition printing method considering regional properties is provided based on the problems.

Disclosure of Invention

The invention aims to provide a fused deposition 3D printing method considering regional performance, which solves the problems of overlarge stress distribution difference and overlarge local stress of the existing irregular plate.

The technical scheme adopted by the invention is as follows: the fused deposition 3D printing method considering regional performance comprises the following specific operation steps:

step 1: storing a three-dimensional model diagram of a printing part generated by three-dimensional modeling software into an STL format for generating a slice and a G-code file;

step 2: and performing first region segmentation and layering treatment on the STL format file. And (3) reading the outer contour of the STL model, performing offset processing on the outer contour to obtain an outer contour part, layering the side surface of the outer contour by adopting a self-adaptive layering algorithm, and printing the upper and lower surfaces by adopting a minimum layer thickness and a minimum line width, thereby obtaining the optimal precision of the printed piece. Layering the inner area from which the outer contour is removed by using the superposition thickness of the self-adaptive layering so as to improve the printing efficiency;

step 3: and performing second region segmentation and path filling on the STL format file. Carrying out stress analysis on the whole part, carrying out region segmentation (region n) on the internal region according to part stress distribution, and then determining filling density according to the stress of each region;

step 4: setting path planning and printing parameters, and then generating a G-code file and printing.

The present invention is also characterized in that,

the step 2 is specifically as follows:

analyzing the existing STL file, and biasing the side profile of the three-dimensional model graph by using a profile biasing algorithm, wherein the biasing distance is C _a ，C _a For the extrusion linewidth at the time of printing with the minimum thickness, and then for the upper and lower surfaces with the layer height h _min Layering, h _min Is the minimum thickness that the printer can print.

Dividing the STL file into two parts, namely an area 1 and an area 2, wherein the area 1 is an external contour, and the area 2 is a part from which the external contour is removed; wherein the thickness of the upper and lower surfaces of the region 1 is h _min ，h _min For the minimum thickness that can be printed by the printer, the thickness of the side profile is offset by a distance C _a The method comprises the steps of carrying out a first treatment on the surface of the Region 1 is then adaptively layered according to the curvature of the side profile, the layer thickness being denoted h _i Obtaining optimal printing precision; then the areas are dividedThe adjacent layer thicknesses obtained by domain 1 layering are overlapped, and the thickness after overlapping is smaller than H _max ，H _max To obtain a new set of layer thicknesses H for the maximum layer thickness that can be printed by the printer _c New layer thickness H _c And layering by applying the method to the region 2 to obtain a contour curve of the region 2 after layering.

Adjacent layer thickness h obtained by layering region 1 _i And h _i+1 Superposing to obtain a superposed thickness H _c Will H _c And H is _max Comparing, if H _c >H _max Will H _c Subtracting the layer thickness h _i+1 Then update save H _c The method comprises the steps of carrying out a first treatment on the surface of the If H _c <H _max Then the next layer is formed into a thickness h _i+2 Continuing to perform superposition, then performing judgment, and sequentially performing the steps to obtain a group of new layer thicknesses H _c 。

The step 3 is specifically as follows: dividing the contour curve after the region layering in the step 2 into n regions according to stress distribution, and determining the density to be filled according to the stress corresponding to each region; the method comprises the following steps:

converting the STL file obtained in the step 1 into an X_T format file, and importing the X_T format file into ANSYS software for stress analysis to obtain a stress distribution diagram of the model; deriving stress values of all the nodes, equally dividing the maximum stress value and the minimum stress difference value into n parts, and then carrying out region segmentation on the printed part by combining the contour curve obtained by the region layering method in the step 2 to obtain n regions, wherein each region has a stress value range corresponding to the n regions, and the stress values of the region are represented by the mode of the node stress in the region; under the same load, the cuboid plates have different filling densities and different stress values, different stress values sigma are obtained by changing the filling size d of the internal filling, and the relation between the size and the stress is sigma=ae by fitting ^-d/t +b, wherein a, t, b are constants; by the above relation, the filling size d of each region is obtained, and the variable density filling is completed.

The step 4 is specifically as follows:

searching an optimal printing track by adopting a path planning algorithm according to the layering thickness obtained in the step 2 and the filling density obtained in the step 3, and setting printing parameters through the layering thickness and the printing track, wherein the upper surface and the lower surface of the area 1 are printed by using the minimum line width; and printing the inner area by adopting the layer thickness matched line width, and finally generating a G-code file.

The fused deposition 3D printing method has the beneficial effects that the fused deposition 3D printing method considering the regional performance firstly improves the printing precision and the printing efficiency. Separating the outer contour of the printing model from the inner region, and printing the outer contour of the printing model by adopting a self-adaptive layering method, so that the printing precision of the outer surface of the model is ensured; the internal area of the printing model is layered by using the superposition thickness of the self-adaptive layering, so that the printing time is shortened, and the printing efficiency is improved.

And secondly, the mechanical property of the printing piece is improved. In the internal region of the printing model, region division is carried out according to the stress distribution condition of the printing piece, and then density filling is carried out according to the stress magnitude born by the region, so that the local stress of the printing piece is reduced, the stress distribution is more uniform, the deformation of the printing piece is reduced, and the mechanical property of the printing piece is improved.

Drawings

FIG. 1 is a flow chart of the present invention.

FIG. 2 is a flow chart of an inside and outside region segmentation and layering algorithm.

FIG. 3 is a flow chart of an inner region segmentation and variable density filling algorithm.

Fig. 4 is a graph showing the comparison of the effects of the conventional slicing algorithm and the slicing algorithm of the present invention.

Fig. 5 is a graph comparing the effects of a conventional filling algorithm and the filling algorithm of the present invention.

Detailed Description

The invention will now be described in detail with reference to the drawings and specific examples.

Example 1

The invention relates to a fused deposition 3D printing method considering regional performance, which is shown in figure 1 and comprises the following specific operation steps:

step 1: storing a three-dimensional model diagram of the printing part generated by the three-dimensional modeling software into an STL format;

step 2: performing first region segmentation and layering treatment on the STL format file;

step 3: performing second region segmentation and filling path determination on the STL format file;

step 4: setting path planning and printing parameters, and then generating a G-code file and printing.

Example 2

As shown in fig. 1, based on embodiment 1, step 2 is specifically as follows:

analyzing the existing STL file, and biasing the side profile of the three-dimensional model graph by using a profile biasing algorithm, wherein the biasing distance is C _a ，C _a For the extrusion linewidth at the time of printing with the minimum thickness, and then for the upper and lower surfaces with the layer height h _min Layering, h _min Is the minimum thickness that the printer can print.

Dividing the STL file into two parts, namely an area 1 and an area 2, wherein the area 1 is an external contour, and the area 2 is a part from which the external contour is removed; wherein the thickness of the upper and lower surfaces of the region 1 is h _min ，h _min For the minimum thickness that can be printed by the printer, the thickness of the side profile is offset by a distance C _a The method comprises the steps of carrying out a first treatment on the surface of the Region 1 is then adaptively layered according to the curvature of the side profile, the layer thickness being denoted h _i Obtaining optimal printing precision; then the adjacent layer thicknesses obtained by layering the area 1 are overlapped, and the thickness after overlapping is smaller than H _max ，H _max To obtain a new set of layer thicknesses H for the maximum layer thickness that can be printed by the printer _c New layer thickness H _c And layering by applying the method to the region 2 to obtain a contour curve of the region 2 after layering.

Adjacent layer thickness h obtained by layering region 1 _i And h _i+1 Superposing to obtain a superposed thickness H _c Will H _c And H is _max Comparing, if H _c >H _max Will H _c Subtracting the layer thickness h _i+1 Then update save H _c The method comprises the steps of carrying out a first treatment on the surface of the If H _c <H _max Then the next layer is formed into a thickness h _i+2 Continuing to perform superposition, then performing judgment, and sequentially performing the steps to obtain a group of new layer thicknesses H _c 。

The step 3 is specifically as follows: dividing the contour curve after the region layering in the step 2 into n regions according to stress distribution, and determining the density to be filled according to the stress corresponding to each region; the method comprises the following steps:

converting the STL file obtained in the step 1 into an X_T format file, and importing the X_T format file into ANSYS software for stress analysis to obtain a stress distribution diagram of the model; deriving stress values of all nodes, equally dividing the maximum stress value and the minimum stress difference value into n parts, and then carrying out region segmentation on a printed part by combining the contour curve obtained by the region layering method in the step 2 to obtain n regions, wherein each region has a stress value range corresponding to the n regions, and the stress values of the region are represented by the mode of the node stress in the region; under the same load, the cuboid plates have different filling densities and different stress values, different stress values sigma are obtained by changing the filling size d of the internal filling, and the relation between the size and the stress is sigma=ae by fitting ^-d/t +b, wherein a, t, b are constants; by the above relation, the filling size d of each region is obtained, and the variable density filling is completed.

The step 4 is specifically as follows:

searching an optimal printing track by adopting a path planning algorithm according to the layering thickness obtained in the step 2 and the filling density obtained in the step 3, and setting printing parameters through the layering thickness and the printing track, wherein the upper surface and the lower surface of the area 1 are printed by using the minimum line width; and printing the inner area by adopting the layer thickness matched line width, and finally generating a G-code file.

Example 3

Step one: STL format file for obtaining model

And using three-dimensional modeling software to obtain a three-dimensional model to be printed, and generating an STL format file for carrying out subsequent slicing layering, region filling and other works.

Step two: internal and external region segmentation and layering algorithm

As shown in FIG. 2, the internal and external region segmentation and layering flows are that the existing STL file is analyzed first, and the profile bias algorithm is used to make the profile of the STL modelOffset, offset distance C _a (C _a Line width of extrusion at minimum thickness printing), and then to the upper and lower surfaces at a layer height h _min (h _min Minimum thickness that can be printed) are layered. The STL file is divided into two parts, region 1 (outer contour) and region 2 (portion of the print model removed region 1), as shown in fig. 4 (right). Wherein the thickness of the upper and lower surfaces of the region 1 is h _min The thickness of the side profile is offset distance C _a . According to the existing self-adaptive layering algorithm, performing self-adaptive layering according to the curvature of the side profile to obtain a group of layer thicknesses h _i Thereby obtaining optimal printing accuracy. Adjacent layer thickness h obtained by layering region 1 _i And h _i+1 Stacking with a stacking thickness H _c Will H _c And H is _max (H _max Maximum layer thickness for a printer) if H _c >H _max Will H _c Subtracting the layer thickness h _i+1 Then store H _c The method comprises the steps of carrying out a first treatment on the surface of the If H _c <H _max Then the next layer is formed into a thickness h _i+2 The superposition is continued, and then the judgment is continued. Sequentially performing the steps to obtain a new set of layer thicknesses H _c . And (5) layering the new layer thickness in the region 2 to obtain a contour curve of the region 2 after layering.

Step three: internal region segmentation and variable density filling algorithm

The flow of the internal region segmentation and variable density filling algorithm is shown in fig. 3, the STL file obtained in the step 1 is converted into an X_T format file, and the X_T format file is imported into ANSYS software for stress analysis to obtain a stress distribution diagram of the model. In ANSYS, stress contours of the printed matter can be obtained, and the respective areas of different stress values can be clearly observed, but the number of divided areas obtained by this method is excessive, which reduces printing efficiency. Therefore, the stress value of the node is derived from ANSYS, the maximum stress value and the minimum stress value are equally divided into n parts (the number of the areas for dividing the printing area), and then the printing piece is divided into n areas by combining the contour curve obtained by the area layering algorithm in the second step, so that n areas are obtained, as shown in fig. 5. Each region has a stress value range corresponding thereto, whereThe mode of node stress in a region represents the stress value of the region. Under the same load, the cuboid plates have different stress values of different filling densities, different stress values sigma are obtained by changing the filling size d of internal filling (namely the size of a filling pattern is larger, the filling density is larger, the filling size is smaller), and the relationship between the size and the stress is sigma=ae is obtained by fitting ^-d/t +b, where A, t, b are constants (the type of function can be modified, and the relationship between stress value and fill size can be met). By the above relation, the filling size d of each region is obtained as shown in fig. 5 (right). And (5) completing variable density filling.

Step four: path planning and parameter setting

According to the layering thickness and the filling density obtained by the inner and outer area segmentation and layering algorithm and the inner area segmentation and variable density filling algorithm, an optimal printing track is searched by adopting the existing path planning algorithm, then printing parameters are set through the layering thickness and the printing track, and the upper surface and the lower surface of the area 1 are printed by using the minimum line width, so that the printing precision is improved; and printing the inner area by adopting the layer thickness matched line width, and finally generating the G-code file. The effect of the conventional slicing algorithm and the inventive slicing algorithm is shown in fig. 4, and the effect of the conventional filling algorithm and the inventive filling algorithm is shown in fig. 5.

Comparing the left and right sides of fig. 4 shows that the print profile obtained according to the inside and outside area division and layering algorithm considers the print precision of the upper and lower surfaces, and improves the precision of the upper and lower surfaces by reducing the print linewidth of the upper and lower surfaces. In addition, the internal area is printed by adopting the superposition thickness of the external contour, so that the printing precision is ensured and the printing efficiency is improved. As can be seen from the comparison of the left and right sides of FIG. 5, the inner filling obtained by the inner region segmentation and variable density filling algorithm can be filled more densely in the outer region of the printed part and the place with smaller included angles of the outline (the gear teeth in FIG. 5), so that the mechanical property of the printed part is improved.

Claims (6)

1. The fused deposition 3D printing method considering regional performance is characterized by comprising the following specific operation steps:

step 1: storing a three-dimensional model diagram of the printing part generated by the three-dimensional modeling software into an STL format;

step 2: performing first region segmentation and layering treatment on the STL format file;

step 3: performing second region segmentation and filling path determination on the STL format file;

step 4: setting path planning and printing parameters, and then generating a G-code file and printing.

2. The fused deposition 3D printing method considering regional performance according to claim 1, wherein step 2 is specifically as follows:

analyzing the existing STL file, and biasing the side profile of the three-dimensional model graph by using a profile biasing algorithm, wherein the biasing distance is C _a ，C _a For the extrusion linewidth at the time of printing with the minimum thickness, and then for the upper and lower surfaces with the layer height h _min Layering, h _min Is the minimum thickness that the printer can print.

3. The fused deposition 3D printing method considering regional performance according to claim 2, wherein step 2 is layered as follows:

dividing the STL file into two parts, namely an area 1 and an area 2, wherein the area 1 is an external contour, and the area 2 is a part from which the external contour is removed; wherein the thickness of the upper and lower surfaces of the region 1 is h _min ，h _min For the minimum thickness that can be printed by the printer, the thickness of the side profile is offset by a distance C _a The method comprises the steps of carrying out a first treatment on the surface of the Region 1 is then adaptively layered according to the curvature of the side profile, the layer thickness being denoted h _i Obtaining optimal printing precision; then the adjacent layer thicknesses obtained by layering the area 1 are overlapped, and the thickness after overlapping is smaller than H _max ，H _max To obtain a new set of layer thicknesses H for the maximum layer thickness that can be printed by the printer _c New layer thickness H _c And layering by applying the method to the region 2 to obtain a contour curve of the region 2 after layering.

4. The fused deposition 3D printing method considering regional performance according to claim 3, wherein the adjacent layer thickness h obtained by layering the region 1 _i And h _i+1 Superposing to obtain a superposed thickness H _c Will H _c And H is _max Comparing, if H _c >H _max Will H _c Subtracting the layer thickness h _i+1 Then update save H _c The method comprises the steps of carrying out a first treatment on the surface of the If H _c <H _max Then the next layer is formed into a thickness h _i+2 Continuing to perform superposition, then performing judgment, and sequentially performing the steps to obtain a group of new layer thicknesses H _c 。

5. The fused deposition 3D printing method considering regional performance according to claim 2, wherein step 3 is specifically as follows: dividing the contour curve after the region layering in the step 2 into n regions according to stress distribution, and determining the density to be filled according to the stress corresponding to each region; the method comprises the following steps:

converting the STL file obtained in the step 1 into an X_T format file, and importing the X_T format file into ANSYS software for stress analysis to obtain a stress distribution diagram of the model; deriving stress values of all the nodes, equally dividing the maximum stress value and the minimum stress difference value into n parts, and then carrying out region segmentation on the printed part by combining the contour curve obtained by the region layering method in the step 2 to obtain n regions, wherein each region has a stress value range corresponding to the n regions, and the stress values of the region are represented by the mode of the node stress in the region; under the same load, the cuboid plates have different filling densities and different stress values, different stress values sigma are obtained by changing the filling size d of the internal filling, and the relation between the size and the stress is sigma=ae by fitting ^-d/t +b, wherein a, t, b are constants; by the above relation, the filling size d of each region is obtained, and the variable density filling is completed.

6. The fused deposition 3D printing method considering regional performance according to claim 5, wherein step 4 is specifically as follows:

searching an optimal printing track by adopting a path planning algorithm according to the layering thickness obtained in the step 2 and the filling density obtained in the step 3, and setting printing parameters through the layering thickness and the printing track, wherein the upper surface and the lower surface of the area 1 are printed by using the minimum line width; and printing the inner area by adopting the layer thickness matched line width, and finally generating a G-code file.