CN-121973448-A - Photo-curing 3D printing support generation method based on suspension angle self-adaption

CN121973448ACN 121973448 ACN121973448 ACN 121973448ACN-121973448-A

Abstract

The application relates to the technical field of photo-curing 3D printing support generation, in particular to a photo-curing 3D printing support generation method based on overhang angle self-adaption, which comprises layering a model and extracting normal vectors and curvatures of triangular patches; the critical overhang angle is calculated dynamically by combining equipment parameters, material characteristics and temperature, an overhang area is identified, risk grades are marked, a support density mapping function is constructed to generate an initial support point, the support network topology is optimized through gradient descent, and support parameters are corrected based on historical collapse data feedback. The application can realize the self-adaptive generation and closed-loop optimization of the supporting structure, and improve the printing success rate and the supporting efficiency.

Inventors

ZHANG ZHONGYANG
LI LUYAO
LI XINE
XIE YING
ZHANG YANG
JIANG XIANGDONG
SUN YICHENG

Assignees

李璐瑶
爱司凯科技股份有限公司

Dates

Publication Date: 20260505
Application Date: 20260206

Claims (7)

1. A photocuring 3D printing support generation method based on suspension angle self-adaption is characterized by comprising the following steps of S1 inputting a three-dimensional model, S2 carrying out voxel layering processing on the input three-dimensional model, extracting normal vector and local curvature information of all surface triangular patches in each layer, S3 calculating a dynamic critical suspension angle threshold corresponding to each local area according to layer thickness parameters of current printing equipment, rheological characteristics of resin materials and environment temperature, S4 identifying a suspension area needing to generate a support by combining space orientation of the triangular patches and the dynamic critical suspension angle threshold, marking risk grades of the suspension area, S5 constructing a support density mapping function based on the risk grades, projection areas of the suspension area and distances between the support and a substrate to generate an initial support point distribution diagram, S6 adjusting support point positions and connection topology by adopting a gradient descent optimization algorithm on the basis of the initial support point distribution diagram to form a support network with a hierarchical density and a directional connection structure, S7 correcting connection strength parameters and density weights of the support network according to actual records of similar geometric characteristics in a historical printing task, and S8 correcting the support network data after the support network is output to be self-adaption structure.
2. The photocuring 3D printing support generation method based on overhang angle self-adaption is characterized in that in S2, voxel layering processing is conducted on an input three-dimensional model, normal vectors and local curvature information (2) of all surface triangular patches in each layer are extracted, the three-dimensional model is sliced along the Z-axis direction according to set layer thickness to generate a discrete layer sequence, neighborhood search is conducted on triangular grids in each layer, unit normal vectors of each triangular patch in a three-dimensional space are calculated, a discrete differential geometric method is adopted, gaussian curvature and average curvature at each vertex are calculated based on difference of normal vectors of adjacent triangular patches, the curvature values and the normal vectors are used as input variables calculated by subsequent dynamic thresholds, and a geometric characteristic data table is built by using layer sequence numbers as indexes.
3. The method for generating the photo-curing 3D printing support based on the suspension angle self-adaption is characterized in that in S3, according to layer thickness parameters of current printing equipment, rheological properties of resin materials and environmental temperature, a dynamic critical suspension angle threshold value (3) corresponding to each local area is calculated, specifically, a process parameter-suspension limit mapping database is established, wherein the process parameter-suspension limit mapping database comprises measured maximum printable suspension angles under different layer thicknesses (25-100 μm), resin viscosities (200-2000 mPa S) and environmental temperature (15-35 ℃), interpolation inquiry is conducted on parameters used for a current printing task to obtain a basic critical angle theta 0 , a local curvature correction factor kappa is introduced, a dynamic critical suspension angle theta=theta 0 × (1-alpha-alpha|kappa|), alpha is an empirical coefficient, the value range is 0.1-0.3, and independent theta values are distributed for each triangular patch to form a suspension judgment threshold value field with spatial variation.
4. The method for generating the photo-curing 3D printing support based on the overhang angle self-adaption is characterized in that in S4, an overhang area needing to be generated is identified by combining the spatial orientation of triangular patches with a dynamic critical overhang angle threshold value, and a risk level (4) of the overhang area is marked, and specifically comprises the steps of calculating an included angle beta between a normal vector of each triangular patch and a positive Z-axis direction, judging that the patch is in an overhang state when beta is more than theta, bringing the area of the patch into a candidate support area, dividing the risk level according to a difference delta beta=beta-theta between beta and theta, wherein delta beta epsilon (0 DEG, 5 DEG, 15 DEG) is low risk, medium risk and 15 DEG is high risk, and carrying out area combination on continuously adjacent equivalent overhang patches to generate an overhang area set with a risk label.
5. The method for generating the photocuring 3D printing support based on the suspension angle self-adaption according to claim 1 is characterized in that in S5, a support density mapping function is built based on risk grades, projection areas and distances between the suspension areas and a substrate, an initial support point distribution map (5) is generated specifically by defining a support density function rho=w 1 ·R + w 2 ·A p + w 3 & H, wherein R is a risk grade coding value (low=1, medium=2 and high=3), A p is a projection area normalization value of the suspension areas on an XY plane, H is a normalized height of a central point of the area from the printing substrate, w 1 、w 2 、w 3 is a preset weight coefficient, support points are distributed in each suspension area according to a poisson disc sampling strategy, point distance d=d 0 / √ρ,d 0 is a reference distance, the support point coordinates are bound with the risk grades of the areas, and the initial support point distribution map is output.
6. The method for generating the photocuring 3D printing support based on the overhang angle self-adaption is characterized in that in the step S6, on the basis of an initial supporting point distribution diagram, a gradient descent optimization algorithm is adopted to adjust the positions and connection topology of supporting points, the forming of a supporting network (6) with a hierarchical density and directional connection structure specifically comprises the steps of constructing a connection diagram between supporting points, initial connection is conducted through Delaunay triangulation, an energy function E=E s + λ·E t is defined, E s is the total length of the supporting structure, E t is an included angle deviation accumulation value of a normal vector of a supporting surface patch and an overhang surface patch, lambda is a direction consistency weight, the coordinates of the supporting points are used as optimization variables, the position is updated through gradient descent iteration, the energy function E is minimized, redundant connection with the energy contribution lower than a threshold value is removed, a main supporting path is reserved, and the lightweight and direction-adaptive supporting network is formed.
7. The photocuring 3D printing support generation method based on overhang angle self-adaption is characterized in that in S7, according to actual collapse records of similar geometric features in a historical printing task, feedback correction (7) is carried out on connection strength parameters and density weights of a support network, wherein the method specifically comprises the steps of establishing a geometric feature-collapse event database, recording area curvature, overhang angles, support densities and actual failure modes of collapse in past printing, improving risk level of an overhang area with the geometric similarity of more than 85% with a historical collapse area in a current model, increasing alpha coefficient to 0.35 of the area in S2 if collapse rate of a certain type of curvature interval (such as |kappa| > 0.8 mm-1) in historical data is higher than 15%, synchronously improving w 1 weight in S4, enabling the high curvature area to automatically obtain higher support density, and completing closed loop parameter correction.

Description

Photo-curing 3D printing support generation method based on suspension angle self-adaption Technical Field The invention belongs to the technical field of additive manufacturing, and particularly relates to a photocuring 3D printing support generation method based on overhang angle self-adaption. Background With the widespread use of photo-curing 3D printing technology, the generation strategy of the support structure has a decisive influence on the printing quality, material consumption and post-processing efficiency. Particularly in printing of complex geometries, overhanging regions, if not reasonably supported, can easily lead to interlayer collapse, surface roughness, and even printing failure. In the prior art, a fixed threshold (such as 45 degrees) is adopted to judge whether support is needed, the adaptive response capability to local geometric characteristics and printing process parameters is lacked, and improvement space exists in the aspect of considering support effectiveness and structure light weight. Through the search, a structural layout, geometry and 3D printing integrated optimization design and manufacturing method with the publication number of CN115635683B is disclosed, and the publication date is 2023, 7, 25 days. The patent creates a self-supporting structure that does not require additional support by screening out components that violate the overhang angle constraint and iteratively merging the components with the nodes during the layout optimization process. The method is mainly suitable for the scene of modifiable original design and has certain limitation when being applied to the existing model which cannot be modified, meanwhile, the suspension angle constraint adopts a global fixed threshold value, the influence of local curvature change, layer thickness difference or resin rheological property on the practical printable suspension limit is not fully considered, and the situation of insufficient support or redundant support can occur in a complex curved surface or a fine characteristic region. Through the search, a three-dimensional self-supporting truss optimization design and manufacturing method based on multi-axis 3D printing with the publication number of CN117235924A is disclosed, and the publication date is 2023, 12, 15. The patent reduces the number of suspension members by integrally optimizing the structural layout and the printing direction, thereby reducing the dependence on the support structure. The scheme is mainly oriented to truss structures under a multi-axis motion system, and is characterized in that self-support is realized by adjusting a printing path and cooperatively optimizing a structural form, coverage is limited for supporting generation problems of a general model in traditional single-axis photo-curing equipment, in addition, the suspension constraint is still based on a preset angle threshold, a dynamic evaluation mechanism for local suspension risk is not introduced, self-adaptive generation and optimization of a supporting structure are not involved, and adaptability is limited when photo-curing printing tasks of non-truss types, high detail or organic forms are processed. The above-mentioned situation shows that the current photo-curing 3D printing support generation method mostly adopts a static threshold value in the suspension angle judgment, the suitability of the local geometric feature and the process condition is to be improved, and the optimization requirement is still met on the premise of not changing the original model to realize the efficient support. Therefore, the invention provides a photocuring 3D printing support generation method based on suspension angle self-adaption, which aims to dynamically adjust a support generation strategy by combining local geometric features and printing conditions, effectively control the support dosage, improve the surface quality and simplify the post-treatment flow while guaranteeing the printing success rate. Disclosure of Invention In order to overcome the above-mentioned drawbacks of the prior art, embodiments of the present invention provide a method for generating a photo-curing 3D printing support based on suspension angle adaptation, so as to solve the above-mentioned problems set forth in the background art. The invention provides a photocuring 3D printing support generation method based on suspension angle self-adaption, which comprises the following steps of S1 inputting a three-dimensional model, S2 carrying out voxel layering processing on the input three-dimensional model, extracting normal vector and local curvature information of all surface triangular patches in each layer, S3 calculating a dynamic critical suspension angle threshold corresponding to each local area according to layer thickness parameters of current printing equipment, rheological properties of resin materials and environmental temperature, S4 combining space orientation of the triangular patches and the dynam