Volumetric adaptive slicing of manifold mesh for rapid prototyping based on relative volume error

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Qianyong Chen ◽  
Jinghua Xu ◽  
Shuyou Zhang
Keyword(s):  
Rapid Prototyping ◽  
Surface Quality ◽  
Relative Volume ◽  
Confocal Laser ◽  
Adaptive Slicing ◽  
Content Type ◽  
Layer Height ◽  
Part Surface ◽  
Slicing Method ◽  
Cusp Height

Purpose Compared with cusp height and area deviation ratio, volume error (VE) caused by the layer height could represent the stair-case effect more comprehensively. The proposed relative volume error (RVE)-based adaptive slicing method takes VE rather than cusp height as slicing criteria, which can improve part surface quality for functionalized additive manufacturing. Design/methodology/approach This paper proposes a volumetric adaptive slicing method of manifold mesh for rapid prototyping based on RVE. The pre-height sequences of manifold mesh are first preset to reduce the SE by dividing the whole layer sequence into several parts. A breadth-first search-based algorithm has been developed to generate a solid voxelization to get VE. A new parameter RVE is proposed to evaluate the VE caused by the sequence of the layer positions. The RVE slicing is conducted by iteratively adjusting the layer height sequences under different constraint conditions. Findings Three manifold models are used to verify the proposed method. Compared with uniform slicing with 0.2 mm layer height, cusp height-based method and area deviation-based method, the standard deviations of RVE of all three models are improved under the proposed method. The surface roughness measured by the confocal laser scanning microscope proves that the proposed RVE method can greatly improve part surface quality by minimizing RVE. Originality/value This paper proposes an RVE-based method to balance the surface quality and print time. RVE could be calculated by voxelized parts with required accuracy at a very fast speed by parallel.

A novel adaptive slicing algorithm based on ameliorative area ratio and accurate cusp height for 3D printing

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yifei Hu ◽  
Xin Jiang ◽  
Guanying Huo ◽  
Cheng Su ◽  
Hexiong Li ◽  
...  
Keyword(s):  
3D Printing ◽  
Surface Quality ◽  
Three Dimensional ◽  
Geometric Error ◽  
Area Ratio ◽  
Adaptive Slicing ◽  
Content Type ◽  
Contour Matching ◽  
Slicing Method ◽  
Cusp Height

Purpose Adaptive slicing is a key step in three-dimensional (3D) printing as it is closely related to the building time and the surface quality. This study aims to develop a novel adaptive slicing method based on ameliorative area ratio and accurate cusp height for 3D printing using stereolithography (STL) models. Design/methodology/approach The proposed method consists of two stages. In the first stage, the STL model is sliced with constant layer thickness, where an improved algorithm for generating active triangular patches, the list is developed to preprocess the model faster. In the second stage, the model is first divided into several blocks according to the number of contours, then an axis-aligned bounding box-based contour matching algorithm and a polygons intersection algorithm are given to compare the geometric information between several successive layers, which will determine whether these layers can be merged to one. Findings Several benchmarks are applied to verify this new method. Developed method has also been compared with the uniform slicing method and two existing adaptive slicing methods to demonstrate its effectiveness in slicing. Originality/value Compared with other methods, the method leads to fewer layers whilst keeping the geometric error within a given threshold. It demonstrates that the proposed slicing method can reach a trade-off between the building time and the surface quality.

A review of slicing methods for directed energy deposition based additive manufacturing

2018 ◽  
Vol 24 (6) ◽  
pp. 1012-1025 ◽  
Author(s):  
Jing Xu ◽  
Xizhi Gu ◽  
Donghong Ding ◽  
Zengxi Pan ◽  
Ken Chen
Keyword(s):  
Additive Manufacturing ◽  
Surface Quality ◽  
Energy Deposition ◽  
Support Structures ◽  
Adaptive Slicing ◽  
Content Type ◽  
Powder Bed ◽  
Directed Energy Deposition ◽  
Slicing Method ◽  
Directed Energy

Purpose The purpose of this paper is to systematically review the published slicing methods for additive manufacturing (AM), especially the multi-direction and non-layerwise slicing methods, which are particularly suitable for the directed energy deposition (DED) process to improve the surface quality and eliminate the usage of support structures. Design/methodology/approach In this paper, the published slicing methods are clarified into three categories: the traditional slicing methods (e.g. the basic and adaptive slicing methods) performed in the powder bed fusion (PBF) system, the multi-direction slicing methods and non-layerwise slicing methods used in DED systems. The traditional slicing methods are reviewed only briefly because a review article already exists for them, and the latter two slicing methods are reviewed comprehensively with further discussion and outlook. Findings A few traditional slicing approaches were developed in the literature, including basic and adaptive slicing methods. These methods are efficient and robust when they are performed in the PBF system. However, they are retarded in the DED process because costly support structures are required to sustain overhanging parts and their surface quality and contour accuracy are not satisfactory. This limitation has led to the development of various multi-direction and non-layerwise slicing methods to improve the surface quality and enable the production of overhangs with minimum supports. Originality/value An original review of the AM slicing methods is provided in this paper. For the traditional slicing methods and the multi-direction and non-layerwise slicing method, the published slicing strategies are discussed and compared. Recommendations for future slicing work are also provided.

A Volumetric Difference-based Adaptive Slicing and Deposition Method for Layered Manufacturing

2003 ◽  
Vol 125 (3) ◽  
pp. 586-594 ◽  
Author(s):  
Y. Yang ◽  
J. Y. H. Fuh ◽  
H. T. Loh ◽  
Y. S. Wong
Keyword(s):  
Local Features ◽  
Layered Manufacturing ◽  
Deposition Method ◽  
Adaptive Slicing ◽  
Surface Normal ◽  
Staircase Effect ◽  
Slicing Method ◽  
Cusp Height ◽  
The Difference ◽  
New Criterion

Adaptive slicing capable of producing variable thickness is a useful means to improve the fabrication efficiency in layered manufacturing (LM) or Rapid Prototyping (RP) processes. Many approaches have been reported in this field; however, most of them are based on the cusp height criteria, which is not an effective representation of the staircase effect when the surface normal is near vertical. Furthermore, most of the existing methods slice the model without considering the local features in the plane of the sliced layer. This paper introduces a novel difference-based adaptive slicing and deposition method. The advantage of this slicing method is that the slicing error is independent of the surface normal. A new criterion for adaptive slicing is evaluated and compared with that based on cusp-height. An adaptive slicing algorithm, which uses the volumetric difference between two adjacent layers as the criterion for slicing, has been developed in this work. Different deposition strategies for the common area and the difference area are applied to layer fabrication while considering the local features of the sliced layer. The algorithm has been tested with a sample part, and the results indicate that a better surface finish can be achieved for both surfaces whose normals are nearly in the slicing plane and surfaces whose normals are nearly perpendicular to the slicing plane. It is found that the building time can be reduced by 40% compared with the traditional adaptive slicing. The proposed method has minimized the volumetric error between the built LM part and the original CAD model while achieving a higher efficiency. It is suitable for most commercialized LM systems due to its simplicity in implementation.

Application of curved layer manufacturing for preservation of randomly located minute critical surface features in rapid prototyping

2015 ◽  
Vol 21 (6) ◽  
pp. 725-734 ◽  
Author(s):  
Yashpal Patel ◽  
Aashish Kshattriya ◽  
Sarat B Singamneni ◽  
A. Roy Choudhury
Keyword(s):  
Rapid Prototyping ◽  
Computer Aided Design ◽  
Critical Surface ◽  
Adaptive Slicing ◽  
Content Type ◽  
Surface Features ◽  
Number Of Layers ◽  
Thin Slices ◽  
Minimum Number ◽  
Pass Through

Purpose – Layered manufacturing with curved layers is a recently proposed rapid prototyping (RP) strategy for the manufacture of curved, thin and shell-type parts and the repair of worn surfaces, etc. The present investigation indicates another possible application area. In case of flat-layered RP of computer-aided design models having randomly located, small-dimensioned but critical surface features, adaptive slicing is resorted to. Large number of thin slices have to be employed to preserve the critical features. In contrast, a considerably lower number of curved thin slices would be required to preserve such surface features in case of RP with curved layers. Design/methodology/approach – The method of preservation of critical features by RP with curved layers is formulated and demonstrated for two clusters of critical features on the surface of a part. A minimum number of such curved layers is identified by application of genetic algorithms (GAs) in case of a simple example. GA evolves the shape of the curved layer passing through the lower cluster so as to make a curved layer pass through the upper cluster of critical features. Findings – In the example part, a 21 per cent reduction in the number of layers is achieved by the application of adaptive curved layers over adaptive straight layers. Originality/value – The novelty of the concept is the proposed use of curved layered RP with adaptive slicing for the preservation of critical features in final prototyped part. This methodology, applied to part with two distinct clusters, leads to reduced number of layers compared to that obtained in flat-layered RP.

Slicing strategy and process of laser direct metal deposition (DMD) of the inclined thin-walled part under open-loop control

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Liaoyuan Chen ◽  
Tianbiao Yu ◽  
Ying Chen ◽  
Wanshan Wang
Keyword(s):  
Dimensional Accuracy ◽  
Deposition Process ◽  
Open Loop ◽  
Adaptive Slicing ◽  
Content Type ◽  
Loop Control ◽  
Slicing Method ◽  
Deposition Thickness ◽  
Thin Walled ◽  
Deposition Height

Purpose The purpose of this paper is to improve the dimensional accuracy of inclined thin-walled parts fabricated by laser direct metal deposition (DMD) under an open-loop control system. Design/methodology/approach In this study, a novel method of the adaptive slicing method and DMD process with feedback adjustment of deposition height has been developed to successively fabricate complex inclined thin-walled square tube elbow parts. The defocus amount was used as a variable to the matching between the deposition thickness and the adaptive slicing height. Findings The low relative error of dimensional accuracy between experimental and designed parts shows that the matching of the single-layer deposition thickness and the adaptive slicing height can be realized by optimizing the defocusing amount. The negative feedback of the thin-wall part height can be achieved when the defocus amount and the z-axis increment are less than deposition thickness. The improvement of dimensional accuracy of inclined thin-walled parts is also attributed to the optimized scanning strategy. Practical implications The slicing method and deposition process can provide technical guidance for other additive manufacturing (AM) systems to fabricate metal thin-walled parts with high dimensional accuracy because the feedback control of deposition height can be realized only by the optimized process. Originality/value This study provides a novel adaptive slice method and corresponding the deposition process, and expands the slicing method of AM metal parts.

Global adaptive slicing of NURBS based sculptured surface for minimum texture error in rapid prototyping

2015 ◽  
Vol 21 (6) ◽  
pp. 649-661 ◽  
Author(s):  
S. Sikder ◽  
A. Barari ◽  
H.A. Kishawy
Keyword(s):  
Rapid Prototyping ◽  
Computer Aided Design ◽  
Error Function ◽  
Cost Effective ◽  
Optimum Number ◽  
Sculptured Surface ◽  
Adaptive Slicing ◽  
Content Type ◽  
Direct Slicing ◽  
Adaptive Direct Slicing

Purpose – This paper aims to propose a global adaptive direct slicing technique of Non-Uniform Rational B-Spline (NURBS)-based sculptured surface for rapid prototyping where the NURBS representation is directly extracted from the computer-aided design (CAD) model. The imported NURBS surface is directly sliced to avoid inaccuracies due to tessellation methods used in common practice. The major objective is to globally optimize texture error function based on the available range of layer thicknesses of the utilized rapid prototyping machine. The total texture error is computed with the defined error function to verify slicing efficiency of this global adaptive slicing algorithm and to find the optimum number of slices. A variety of experiments are conducted to study the accuracy of the developed procedure, and the results are compared with previously developed algorithms. Design/methodology/approach – This paper proposes a new adaptive algorithm which globally optimizes a texture error function produced by staircase effect for a user-defined number of layers. The adaptive slicing algorithm dynamically calculates optimized slicing thicknesses based on the rapid prototyping machine’s specifications to minimize the texture error function. This paper also compares the results of implementing the developed methodology with the results of previously developed algorithms and presents cost-effective optimum slicing layer thicknesses. Findings – A new methodology for global adaptive direct slicing algorithm of CAD models, based on a texture error function for the final product and the possible layer thicknesses in rapid prototyping, has been developed and implemented. Comparing the results of implementation with the common practice for several case studies shows that the proposed approach has greater slicing efficiency. Typically, by utilizing this approach, the number of prototyping layers can be reduced by 20-50 per cent compared to the slicing with other algorithms, while maintaining or improving the accuracy of the final manufactured surfaces. Therefore, the developed slicing method provides a better solution to trade-off between the rapid prototyping time and the rapid prototyping accuracy. For the many advantages of global direct slicing, it can be seen as the future solution to the slicing process in rapid prototyping systems. Originality/value – This paper presents an innovative approach in direct global adaptive slicing of the additive manufacturing parts. The novel definition of an error function which comprehensively addresses the resulting manufactured surface quality of the entire product allows presenting an objective function to solve and to find the optimum selection of all the layer thicknesses during the slicing process.

The mechanism of process parameters influencing the AlSi10Mg side surface quality fabricated via laser powder bed fusion

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shimin Dai ◽  
Hailong Liao ◽  
Haihong Zhu ◽  
Xiaoyan Zeng
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Process Parameters ◽  
Laser Power ◽  
Side Surface ◽  
Laser Powder Bed Fusion ◽  
Scanning Velocity ◽  
Content Type ◽  
Powder Bed

Purpose For the laser powder bed fusion (L-PBF) technology, the side surface quality is essentially important for industrial applicated parts, such as the inner flow parts. Contour is generally adopted at the parts’ outline to enhance the side surface quality. However, the side surface roughness (Ra) is still larger than 10 microns even with contour in previous studies. The purpose of this paper is to study the influence of contour process parameters, laser power and scanning velocity on the side surface quality of the AlSi10Mg sample. Design/methodology/approach Using L-PBF technology to manufacture AlSi10Mg samples under different contour process parameters, use a laser confocal microscope to capture the surface information of the samples, and obtain the surface roughness Ra and the maximum surface height Rz of each sample after analysis and processing. Findings The results show that the side surface roughness decreases with the increase of the laser power at the fixed scanning velocity of 1,000 mm/s, the side surface roughness Ra stays within the error range as the contour velocity increases. It is found that the Ra increases with the scanning velocity increasing and the greater the laser power with the greater Ra increases when the laser power of contour process parameters is 300 W, 350 W and 400 W. The Rz maintain growth with the contour scanning velocity increasing at constant laser power. The continuous uniform contour covers the pores in the molten pool of the sample edge and thus increase the density of the sample. Two mechanisms named “Active adhesion” and “Passive adhesion” cause sticky powder. Originality/value Formation of a uniform and even contour track is key to obtain the good side surface quality. The side surface quality is determined by the uniformity and stability of the contour track when the layer thickness is fixed. These research results can provide helpful guidance to improve the surface quality of L-PBF manufactured parts.

SURFACE ROUGHNESS IMPROVEMENT OF PARTS MADE OF POLYMERIC MATERIALS OBTAINED BY MEANS OF ADDITIVE TECHNOLOGIES

2021 ◽  
Vol 2021 (7) ◽  
pp. 12-18
Author(s):  
Mikhail Kulikov ◽  
Maksim Larionov ◽  
Denis Gusev ◽  
Evgeniy Shevchuk
Keyword(s):  
Surface Quality ◽  
Polymeric Materials ◽  
Additive Technologies ◽  
Abrasive Tool ◽  
Technological Basis ◽  
Dry Processing ◽  
Investigation Methods ◽  
Before And After ◽  
Part Surface ◽  
Surface Layer Quality

In the paper there is under consideration an effort to achieve the roughness index of Ra <0.8 with the aid of soft abrasive tool use. As a result the purpose of this work became development of the technology for surface quality improvement of parts manufactured with the aid of additive technologies. The authors carried out a number of experiments with the samples manufactured with the aid of the method of FDM print. With the aid of 3D Ultra 3 printer of EnvisionTec company. The samples were made of ABS-plastic in the amount of 6 pieces. On each sample there were defects after printing which contributed to the deterioration of surface quality in products. By means of TR220 profilometer there was measured roughness before and after the experiment. There was carried out dry processing and with the use of SCL. As a result, dry processing resulted in worsening surface quality, heavy wear of an abrasive tool and grain contamination. Analyzing the data obtained from the profilometer in the experiment and SCL use a considerable improvement of the surface layer quality at minimum allowance is observed. Investigation methods: in the work basis there are experimental methods of investigation. The investigations are carried out with the use of a microscope and profilometer. Processing investigation results was carried out as a result of the comparison of the measuring data obtained. Work Novelty: there are defined conditions of soft abrasive tool operation and SCL impact upon Ra indices. The results obtained indicate a possibility of Ra improvement on a part surface which is achieved due to a combined shaping with the aid of additive technologies and further machining carried out on a single technological basis. The experience without SCL use has shown the overheating possibility the result of which is a meltback and plastic sticking both on the surface, and on abrasive grains of the cutter which is inadmissible and results in considerable worsening of Ra on the surface machined and cutter wear. In view of this the SCL use in finishing is promising, but to achieve better results SCL chemistry must be improved.

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