A polygons Boolean operations-based adaptive slicing with sliced data for additive manufacturing

2016 ◽  
Vol 231 (15) ◽  
pp. 2783-2799 ◽  
Author(s):  
Guoqiang Fu ◽  
Jianzhong Fu ◽  
Zhiwei Lin ◽  
Hongyao Shen ◽  
Yu’an Jin
Keyword(s):  
Additive Manufacturing ◽  
Area Ratio ◽  
Multiple Models ◽  
Normal Vector ◽  
Boolean Operations ◽  
Minimum Thickness ◽  
Adaptive Slicing ◽  
Cusp Height ◽  
Surface Precision ◽  
Two Parameters

In order to increase the efficiency of additive manufacturing, this paper proposes a novel adaptive slicing approach of sliced data with minimum thickness based on Boolean operations of polygons. It can greatly handle the balance between the build time and the surface precision of additive manufacturing. The proposed adaptive slicing is available for the single solid model, the support of additive manufacturing, and simultaneously manufactured multiple models. At first, the Boolean operations of polygons are used to gain the relationship of the adjacent layers to serve as the topological information. Second, two parameters are proposed to evaluate the precision of sliced surface: the ameliorative area ratio and variation of the cusp height. Ameliorative area ratio overcomes the drawbacks of original area deviation ration criteria and can work on the large and complex models. Variation of the cusp height makes the calculation of cusp height suitable for sliced data of model, and it is independent of the normal vector of surfaces. Third, the adaptive slicing is realized by removing unnecessary layers based on two parameters and the maximum allowable thickness. The thicknesses are times of the minimum thickness. Moreover, the adaptive slicing for support of additive manufacturing is developed through dividing the support into two parts according to its height and location. Slicing of multiple models is also proposed by choosing the maximum ameliorative area ratio and variation of the cusp height among all models in the same z level as the two parameters. Finally, the adaptive slicing for the three types is tested with some special models, and corresponding models are printed with FDM technology based on slicing results of the proposed approach. Results show that the proposed adaptive slicing approach is effective.

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.

scholarly journals Combined Manufacturing Process of Copper Electrodes for Micro Texturing Applications (AMSME)

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2497
Author(s):  
Carlos J. Sánchez ◽  
Pedro M. Hernández ◽  
María D. Martínez ◽  
María D. Marrero ◽  
Jorge Salguero
Keyword(s):  
Additive Manufacturing ◽  
Surface Texturing ◽  
Surface Finishing ◽  
Minimum Thickness ◽  
Laboratory Equipment ◽  
Digital Light Processing ◽  
Copper Electrodes ◽  
Electro Discharge Machining ◽  
Detailed Surface ◽  
Made In

Surface texturing has brought significant improvements in the functional properties of parts and components. Sinker electro discharge machining (SEDM) is one of the processes which generates great texturing results at different scale. An electrode is needed to reproduce the geometry to be textured. Some geometries are difficult or impossible to achieve on an electrode using conventional and even unconventional machining methods. This work sets out the advances made in the manufacturing of copper electrodes for electro erosion by additive manufacturing, and their subsequent application to the functional texturing of Al-Cu UNS A92024-T3 alloy. A combined procedure of digital light processing (DLP) additive manufacturing, sputtering and micro-electroforming (AMSME), has been used to produce electrodes. Also, a specific laboratory equipment has been developed to reproduce details on a microscopic scale. Shells with outgoing spherical geometries pattern have been manufactured. AMSME process has shown ability to copper electrodes manufacturing. A highly detailed surface on a micrometric scale have been achieved. Copper shells with minimum thickness close to 300 µm have been tested in sinker electro discharge machining (SEDM) and have been shown very good performance in surface finishing operations. The method has shown great potential for use in surfaces texturing.

Increasing Part Accuracy in Additive Manufacturing Processes Using a k-d Tree Based Clustered Adaptive Layering

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Neeraj Panhalkar ◽  
Ratnadeep Paul ◽  
Sam Anand
Keyword(s):  
Additive Manufacturing ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Layer By Layer ◽  
Adaptive Slicing ◽  
Stl File ◽  
Build Time ◽  
Standard File Format ◽  
Aided Design ◽  
Profile Errors

Additive manufacturing (AM) is widely used in aerospace, automobile, and medical industries for building highly accurate parts using a layer by layer approach. The stereolithography (STL) file is the standard file format used in AM machines and approximates the three-dimensional (3D) model of parts using planar triangles. However, as the STL file is an approximation of the actual computer aided design (CAD) surface, the geometric errors in the final manufactured parts are pronounced, particularly in those parts with highly curved surfaces. If the part is built with the minimum uniform layer thickness allowed by the AM machine, the manufactured part will typically have the best quality, but this will also result in a considerable increase in build time. Therefore, as a compromise, the part can be built with variable layer thicknesses, i.e., using an adaptive layering technique, which will reduce the part build time while still reducing the part errors and satisfying the geometric tolerance callouts on the part. This paper describes a new approach of determining the variable slices using a 3D k-d tree method. The paper validates the proposed k-d tree based adaptive layering approach for three test parts and documents the results by comparing the volumetric, cylindricity, sphericity, and profile errors obtained from this approach with those obtained using a uniform slicing method. Since current AM machines are incapable of handling adaptive slicing approach directly, a “pseudo” grouped adaptive layering approach is also proposed here. This “clustered slicing” technique will enable the fabrication of a part in bands of varying slice thicknesses with each band having clusters of uniform slice thicknesses. The proposed k-d tree based adaptive slicing approach along with clustered slicing has been validated with simulations of the test parts of different shapes.

Experimental Investigation on Additively Manufactured Transpiration and Film Cooling Structures

2018 ◽  
Author(s):  
Zheng Min ◽  
Gan Huang ◽  
Sarwesh Narayan Parbat ◽  
Li Yang ◽  
Minking K. Chyu
Keyword(s):  
Additive Manufacturing ◽  
Blood Vessel ◽  
Film Cooling ◽  
Area Ratio ◽  
Manufacturing Technology ◽  
Transpiration Cooling ◽  
Fluid Interface ◽  
Interface Area ◽  
Cooling Effectiveness ◽  
Additive Manufacturing Technology

The last 50 years has witnessed significant improvement in film cooling technologies while transpiration cooling is still not implemented in turbine airfoil cooling. Although transpiration cooling could provide higher cooling efficiency with less coolant consumption compared to film cooling, the fine pore structure and high porosity in transpiration cooling metal media always raised difficulties in conventional manufacturing. Recently, the rapid development of additive manufacturing has provided a new perspective to address such challenge. With the capability of the innovative powder bed selective laser metal sintering (SLMS) additive manufacturing technology, the complex geometries of transpiration cooling part could be precisely fabricated and endued with improved mechanical strength. Present study utilized the SLMS additive manufacturing technology to fabricate the transpiration cooling and film cooling structures with Inconel 718 supperalloy. Five different types of porous media including two perforated plates with different hole pitches, metal sphere packing, metal wire mesh and blood vessel shaped passages for transpiration cooling were fabricated by EOS M290 System. One laidback fan-shaped film cooling coupon was also fabricated with the same printing process as the control group. Heat transfer tests under 3 different coolant mass flow rates and 4 different mainstream temperatures were conducted to evaluate the cooling performance of the printed coupons. The effects of geometry parameters including porosity, surface outlet area ratio and internal solid-fluid interface area ratio were investigated as well. The results showed that the transpiration cooling structures generally had higher cooling effectiveness than film cooling structure. The overall average cooling effectiveness of blood vessel shaped transpiration cooling reached 0.35, 0.5 and 0.57 respectively with low (1.2%), medium (2.4%) and high (3.6%) coolant injection ratios. The morphological parameters analysis showed the major factor that affected the cooling effectiveness most was the internal solid-fluid interface area ratio for transpiration cooling. This study showed that additive manufactured transpiration cooling could be a promising alternative method for turbine blade cooling and worthwhile for further investigations.

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.

Development of a deposition framework for implementation of a region-based adaptive slicing strategy in arc-based metal additive manufacturing

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nitish P. Gokhale ◽  
Prateek Kala
Keyword(s):  
Additive Manufacturing ◽  
Manufacturing Process ◽  
Complex Geometry ◽  
Dimensional Accuracy ◽  
Successful Implementation ◽  
Mathematical Function ◽  
Adaptive Slicing ◽  
Content Type ◽  
Metal Additive Manufacturing ◽  
Metal Additive

Purpose This study aims to develop and demonstrate a deposition framework for the implementation of a region-based adaptive slicing strategy for the Tungsten Inert Gas (TIG) welding-based additive manufacturing system. The present study demonstrates a deposition framework for implementing a novel region-based adaptive slicing strategy termed as Fast Interior and Accurate Exterior with Constant Layer Height (FIAECLH). Design/methodology/approach The mentioned framework has been developed by performing experiments using the design of experiments and analyzing the experimental data. Analysis results have been used to obtain the mathematical function to integrate customization in the process. The paper, in the end, demonstrates the FIAECLH framework for implementing region-based adaptive slicing strategy on the hardware level. Findings The study showcase a new way of implementing the region-based adaptive slicing strategy to arc-based metal additive manufacturing. The study articulating a new strategy for its implementation in all types of wire and arc additive manufacturing processes. Originality/value Wire-arc-based technology has the potential to deliver cost-effective solutions for metal additive manufacturing. The research on arc welding-based processes is being carried out in different dimensions. To deposit parts with complex geometry and better dimensional accuracy implementation of a novel region-based adaptive slicing strategy for the arc-based additive manufacturing process is an essential task. The successful implementation of an adaptive slicing strategy would ease the fabrication of complex geometry in less time. This paper accomplishes this need of implementing a region-based adaptive slicing strategy as no experimental investigation has been reported for the TIG-based additive manufacturing process.

scholarly journals A variational formulation for computing shape derivatives of geometric constraints along rays

2020 ◽  
Vol 54 (1) ◽  
pp. 181-228 ◽  
Author(s):  
Florian Feppon ◽  
Grégoire Allaire ◽  
Charles Dapogny
Keyword(s):  
Velocity Field ◽  
Shape Optimization ◽  
Explicit Knowledge ◽  
Optimization Problems ◽  
Geometric Constraints ◽  
Normal Vector ◽  
Minimum Thickness ◽  
Full Generality ◽  
Structural Shape ◽  
Shape Derivatives

In the formulation of shape optimization problems, multiple geometric constraint functionals involve the signed distance function to the optimized shape Ω. The numerical evaluation of their shape derivatives requires to integrate some quantities along the normal rays to Ω, a challenging operation to implement, which is usually achieved thanks to the method of characteristics. The goal of the present paper is to propose an alternative, variational approach for this purpose. Our method amounts, in full generality, to compute integral quantities along the characteristic curves of a given velocity field without requiring the explicit knowledge of these curves on the spatial discretization; it rather relies on a variational problem which can be solved conveniently by the finite element method. The well-posedness of this problem is established thanks to a detailed analysis of weighted graph spaces of the advection operator β ⋅ ∇ associated to a C1 velocity field β. One novelty of our approach is the ability to handle velocity fields with possibly unbounded divergence: we do not assume div(β) ∈ L∞. Our working assumptions are fulfilled in the context of shape optimization of C2 domains Ω, where the velocity field β = ∇dΩ is an extension of the unit outward normal vector to the optimized shape. The efficiency of our variational method with respect to the direct integration of numerical quantities along rays is evaluated on several numerical examples. Classical albeit important implementation issues such as the calculation of a shape’s curvature and the detection of its skeleton are discussed. Finally, we demonstrate the convenience and potential of our method when it comes to enforcing maximum and minimum thickness constraints in structural shape optimization.

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