CN107187056A - The complex parts 3D printing method and system being layered based on curved surface - Google Patents

Abstract

A 3D printing method and system for complex parts based on surface layering, which establishes its 3D model according to the structure and surface features of the complex part, and performs structural lightweight topology optimization design and spatial 3D slice layering to generate control for 3D printing data; set the printing parameters according to the control data and then perform layer-by-layer 3D printing to obtain 3D prints of complex parts; spatial 3D slice layering refers to: according to the structural characteristics of the 3D model of complex parts, select the surface layering method to perform surface Layering, the layered spatial 3D layered data is processed and the filling strategy is selected to plan the printing path and trajectory; compared with the existing CNC processing technology, the present invention is conducive to the realization of continuous fiber reinforced manufacturing and effectively improves the complexity. The surface forming accuracy of the part reduces printing support.

Description

3D printing method and system for complex parts based on surface layering

technical field

The present invention relates to a technology in the field of 3D printing of complex parts, in particular to a method and system for 3D printing of complex parts based on curved surface layering.

Background technique

For 3D printing of complex parts, the existing layering methods are all 2D layering, that is, layered slicing based on equal layer thickness, variable layer thickness, and multi-directional methods. Printing in one direction cannot solve the support problem; the slicing method with variable layer thickness improves the printing accuracy by reducing the thickness of the slice layer when there is a curved surface in the vertical direction; while multi-directional slicing will bring huge damage to complex parts. Upfront slice processing costs. The filling methods mainly include Raster, Zigzag, Contour, Hybrid, Continuous, medial axis transformation, etc. Through different filling methods in the 2D plane, both filling efficiency and printing accuracy are considered. However, the contour fitting error in the 2D plane and the stacking error in the Z-axis direction still exist. The existing multi-degree-of-freedom printing equipment relies on the existing 2D slicing method and the filling strategy in the 2D plane, and does not really use the 3D slicing method to achieve smooth surface of the printed part, free surface curve gradient and adjustment of layers. Weak connection between.

Contents of the invention

Aiming at the above-mentioned deficiencies in the prior art, the present invention proposes a method and system for 3D printing of complex parts based on curved surface layering, combining the structure, surface and function of complex parts to select curved surface layering and filling strategies, plan the printing trajectory, and convert Perform 3D printing and post-processing for the control data of the printing equipment, so as to realize the 3D printing combined with the surface layering of complex parts.

The present invention is achieved through the following technical solutions:

The present invention establishes its three-dimensional model according to the structure, curved surface characteristics and process requirements of complex parts, and performs structural lightweight topology optimization design and space 3D slice layering to generate control data for 3D printing; print parameter setting is performed according to the control data Afterwards, 3D printing is carried out layer by layer to obtain 3D printed parts of complex parts.

The structures of the complex parts include: space special-shaped pipeline structures, integrated complex structures, space free-form surface structures and other structures with large Z-direction slice stacking errors. If this type of structure adopts the existing Z-direction slices, the way of XY plane printing will cause stacking errors.

The curved surface features include: free curved surfaces in space, curved surfaces of revolution, and other curved surfaces with large curvature along the Z direction.

The process requirements include: some parts require better tensile and compressive properties in the Z direction, so that the microstructure of the printed part is required to grow along a certain direction, that is, the printing direction is consistent with the growth direction.

The above-mentioned establishment is realized by using three-dimensional modeling software for modeling based on the shape, properties and process material requirements of the printed object itself.

The three-dimensional model is drawn by three-dimensional modeling software.

The lightweight topology optimization design of the structure includes: structural function analysis, bearing performance constraint analysis and stress characteristic analysis.

The structure-function analysis refers to analyzing key structures and functions to further ensure that the structures and functions can meet the design requirements. In the case of satisfying the structural function, the structural lightweight topology optimization is carried out.

The load-bearing performance constraint analysis refers to analyzing the load-bearing performance constraints in all directions of the printed part itself, which affect the printing and forming movement mode, and performing structural lightweight topology optimization under the condition of meeting the load-bearing performance constraints.

The stress characteristic analysis refers to: analyzing the stress characteristic required by the printed part itself, and performing structural lightweight topology optimization under the condition that the stress requirement is met.

The described spatial 3D slice layering refers to: according to the structural characteristics of the three-dimensional model of the complex part, the surface layering method is selected to perform the surface slice layering, and the layered spatial 3D layered data is processed and then filled with a filling strategy. Carry out printing path and trajectory planning. The layering direction is along the radial direction, by enveloping the data of the innermost layer and the outermost layer, and then selecting the appropriate filling strategy to print layer by layer, along the radial direction, from outside to inside or from inside to outside for stacking .

The method for layering selected curved surfaces includes, but is not limited to: following the direction of fiber growth or combining structures and curved surfaces.

The layering direction of the curved surface slices can be from inside to outside and from outside to inside, and the layer thicknesses are equal or different.

The control data includes, but is not limited to: driving data for controlling each motor and timing data for linkage between each motor.

The layer-by-layer 3D printing refers to layer-by-layer printing combined with CNC machining to control the forming accuracy, and after each layer or several layers are printed, the process is strengthened by applying pressure along the normal direction of the forming surface.

The present invention relates to a system for implementing the above method, including: three-dimensional modeling of complex parts, lightweight topology optimization module, spatial 3D slice layering module, control data generation module, printing parameter setting module, data transmission and 3D printing module and post-processing module, in which: the 3D modeling of complex parts and the structural lightweight topology optimization module are transferred through the 3D model data, and the structural lightweight topology optimization module and the spatial 3D control data generation module are passed through the slicing and layering module The STL model performs data transfer, the spatial 3D control data generation module slice layering module includes space layering and printing trajectory generation, the control data generation module converts the printing trajectory obtained by the spatial 3D control data generation module slice layering module into the linkage of each motor Control data, set the printing parameters through the printing parameter setting module, use the data transmission and 3DD printing module to realize the data transmission between the upper and lower computers, and print with the help of the printing parameters set by the printing parameter setting module, so as to realize The entire 3D control data generation module prints forming, combined with the post-processing module, performs certain post-processing on the prints to obtain the final prints.

technical effect

Compared with the prior art, the present invention uses three-dimensional space 3D curved surface layering, combined with multi-degree-of-freedom 3D printing equipment for printing and manufacturing, which is different from the existing 2D slice layering method, that is, slice layering in the Z direction, step by step Layer filling; different from the existing 2.5D layering, that is, slicing and layering in different directions and filling layer by layer, it is conducive to the realization of continuous fiber reinforced manufacturing, the enhancement of bearing capacity, and less printing support; and the use of complex The structural function and load-bearing performance constraints of the parts and the analysis of the stress characteristics are used for structural lightweight topology optimization design, which further optimizes the overall structure, reduces processing materials, reduces costs, and improves efficiency.

Description of drawings

Fig. 1 is a schematic diagram of the present invention;

Fig. 2 is a schematic diagram of the surface layering method of complex parts;

In the figure: (a) is before layering, (b) is after layering;

Fig. 3 is the schematic flow chart of embodiment 1;

4 is a schematic diagram of a six-dimensional force sensor model in Embodiment 1;

Fig. 5 is a layered schematic diagram of a six-dimensional force sensor space 3D curved surface;

Figure 6 is a schematic diagram of the layered structure after the lightweight topology optimization design of the six-dimensional force sensor structure;

Among the figure: 1 is the lower platform, 2 and 4 are flexible hinges, 3 is a flexible beam, and 5 is an upper platform.

detailed description

The embodiments of the present invention are described in detail below. This embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operating procedures are provided, but the protection scope of the present invention is not limited to the following implementation example.

Example 1

As shown in Figures 1 to 3, the complex part of this embodiment is a six-dimensional force sensor, which specifically includes the following steps:

Step 1. Draw a three-dimensional model of the elastic body of the six-dimensional force sensor by using three-dimensional modeling software according to the structure and surface characteristics of the six-dimensional force sensor.

The six-dimensional force sensor adopts a form based on a Stewart parallel mechanism, including an upper platform 5, a lower platform 1, flexible hinges 2, 4 and a flexible beam 3 of the six-dimensional force sensor, wherein: the flexible hinges 2 and 4 are six-dimensional force sensors. The key structural part of the sensor.

The three-dimensional modeling software includes but not limited to: Solidworks, ProE or Catia.

Step 2. Perform lightweight topology optimization design on the 3D model obtained in step 1, as shown in Figure 6.

The lightweight topology optimization design of the structure is based on structural function analysis, bearing performance constraint analysis and stress characteristic analysis.

The structural function analysis and load-bearing performance constraint analysis can be performed using HyperMesh, HyperView, OptiStruct or HyperStudy, and the stress characteristic analysis is performed using Ansys software combined with MATLAB.

Step 3, as shown in Fig. 4 and Fig. 5, perform spatial 3D slice layering on the optimized 3D model in step 2, and generate motion control data of the 3D printing device.

The described space 3D slice layering is realized by corresponding software, and this software is based on MATLAB or C ++ as kernel, and C# is the self-developed layered slicing software of interface, by reading three-dimensional model file, obtain outline data, adjust corresponding Parameters, and use offset and other methods to layer the surface, obtain slice layered data, and then combine the structure of the complex part itself, surface characteristics, and process requirements to select an appropriate surface filling strategy to generate control data for surface filling.

The described spatial 3D slice layering comprises the following steps:

S1: According to the structural characteristics of the 3D model of the six-dimensional force sensor, the surface layering method combining structure and surface follow-up is selected for surface slice layering, so as to realize the additive manufacturing of continuous fiber reinforcement.

The layering direction of the curved surface slices is from inside to outside.

S2: After processing the layered spatial 3D layered data, select a filling strategy, and plan the printing path and trajectory based on the printing process requirements and the performance indicators of the six-dimensional force sensor.

The filling strategy includes but not limited to: spatial zigzag filling, continuous spatial curve filling or spatial raster filling.

S3: Transform spatial 3D layering and filling data into motion control data for 3D printing devices.

Step 4. Set the printing parameters according to the motion control data, and use the material synchronous feeding additive manufacturing technology to perform layer-by-layer 3D printing to obtain the 3D printed parts of the elastic body of the six-dimensional force sensor.

The material synchronous feeding additive manufacturing technology refers to but not limited to laser cladding of coaxial or side-axis powder feeding materials, welding of synchronous wire feeding materials and other lamination manufacturing methods with spatial forming capabilities.

The layer-by-layer 3D printing refers to: layer-by-layer printing, combined with CNC processing to control the forming accuracy, and after each layer or several layers are printed, the processing is strengthened by applying pressure along the normal direction of the forming surface to enhance the quality of the printed parts. strength.

The 3D printing equipment described has multiple degrees of freedom, which is different from the existing 3-axis mobile 3D printers, such as 6DOFStewart 3D Printer, Dutch 3D printer Mataerial with a mechanical arm structure, and DMG Lasertec of DMGMORI in Germany with a five-axis linkage method. 65.

The control of forming precision is realized by the printing head, which has spatial forming capability relative to the printing platform, such as FDM printing head, laser printing head, welding torch, etc. During the printing process, different printing processes can be combined to control the printing forming precision.

In order to ensure the accuracy, composite manufacturing combining additive manufacturing and subtractive manufacturing, such as milling and grinding, can be used.

Step 5. Perform post-processing on the printed document, and the printing is completed.

The post-treatment refers to: the strength treatment of the printed part, ie heat treatment, and the surface treatment of the printed part, so as to further improve the surface forming quality.

The printed part uses spatial curves to fill the layers of the curved surface, eliminating the existing stacking error in the Z direction; and the printing method is based on a multi-degree-of-freedom 3D printing device, and when printing a structure similar to a cantilever beam, no printing support is required structure, while reducing printing materials, it also improves printing efficiency.

This embodiment is different from the traditional CNC manufacturing method of the six-dimensional force sensor. It adopts layer-by-layer printing and layer-by-layer pressure along the normal direction of the forming surface for strengthening. At the same time, it can be realized by combining milling or grinding with subtractive manufacturing. Composite manufacturing, high strength while improving forming accuracy, that is, improving the surface accuracy of complex parts, increasing the printing strength of complex parts, achieving smooth surface of printed parts, free surface curve gradient, and adjusting weak connections between layers.

The above specific implementation can be partially adjusted in different ways by those skilled in the art without departing from the principle and purpose of the present invention. The scope of protection of the present invention is subject to the claims and is not limited by the above specific implementation. Each implementation within the scope is bound by the invention.

Claims (9)

1. A complex part 3D printing method based on surface layering, characterized in that, according to the structure and surface features of the complex part, its three-dimensional model is established, and the lightweight topology optimization design and spatial 3D slice layering are carried out to generate 3D printing control data; according to the control data, the printing parameters are set and then 3D printing is performed layer by layer to obtain 3D printed parts of complex parts; The described spatial 3D slice layering refers to: according to the structural characteristics of the three-dimensional model of the complex part, the surface layering method is selected to perform the surface slice layering, and the layered spatial 3D layered data is processed and then filled with a filling strategy. Carry out printing path and trajectory planning. 2. The 3D printing method for complex parts according to claim 1, wherein the basis for the lightweight topology optimization design of the structure is structural function analysis, bearing performance constraint analysis and stress characteristic analysis. 3. The 3D printing method for complex parts according to claim 1, wherein the layering method for selecting curved surfaces includes but not limited to: following the direction of fiber growth or combining structures and curved surfaces. 4. The 3D printing method for complex parts according to claim 1, wherein the layering direction of the curved surface slices can be from inside to outside and from outside to inside, and the layer thicknesses are equal or different. 5. The 3D printing method for complex parts according to claim 1, characterized in that, said layer-by-layer 3D printing refers to layer-by-layer printing combined with CNC processing to control the forming accuracy, and after each layer or several layers are printed, it is printed along the Processing strengthening is carried out by applying pressure in the normal direction of the forming surface. 6. The 3D printing method for complex parts according to claim 1, wherein the structures of the complex parts include: space special-shaped pipeline structure, integrated complex structure and space free-form surface structure. 7. The 3D printing method for complex parts according to claim 1, wherein the curved surface features include: free curved surfaces in space and curved surfaces of revolution. 8. The method for 3D printing of complex parts according to claim 1, characterized in that the establishment is realized by using 3D modeling software for modeling based on the shape, properties and process material requirements of the printed object itself. 9. A system for realizing the method according to any one of the above claims, characterized in that it includes: three-dimensional modeling of complex parts, structure lightweight topology optimization module, spatial 3D slice layering module, control data generation module, printing parameters Setting module, data transmission and 3D printing module and post-processing module, among which: 3D modeling of complex parts and structure lightweight topology optimization module are transmitted through 3D model data, structure lightweight topology optimization module and space 3D control data Generation module Slicing and layering modules perform data transfer through the STL model, the spatial 3D control data generation module slice layering module includes spatial layering and printing track generation, the control data generation module obtains the spatial 3D control data generation module slice layering module The printing trajectory of the computer is converted into the control data of each motor linkage, the printing parameters are set through the printing parameter setting module, the data transmission between the upper and lower computers is realized by using the data transmission and 3DD printing module, and the printing parameter setting module is used to set Print with certain printing parameters, so as to realize the forming of the printed part of the entire 3D control data generation module, and combine with the post-processing module to perform certain post-processing on the printed part to obtain the final printed part.