A topology optimization approach to structure design with self-supporting constraints in additive manufacturing

Wu Zijun,Xiao Renbin 한국CDE학회 2022 Journal of computational design and engineering Vol.9 No.2

The manufacturability model of complex structure is the premise of manufacturing, and it is necessary to consider material properties, structure design, manufacturing constraints, and so on. However, due to the inconsistent restrictions between design and manufacturing, it is not easy to obtain the manufacturable structure that matches its design performance using layer-wise manufacturing. This paper presents a topology optimization method for manufacturable form, which incorporates the self-supporting factors such as overhang angle and length based on the characteristics of the generic additive manufacturing process. The support relationship between the supporting and supported elements in self-supporting constraints is mapped to a cascade relationship between two adjacent layers. To avoid a low-density structure supporting multiple high-density ingredients, we establish a fabrication model using the smax and smin operators. Also, the sensitivity analysis and variable updating method are given under the Solid Isotropic Material with Penalization method. Furthermore, numerical examples are shown to validate the correctness and superiority of this proposed self-supporting structure design method.

Machine Learning for Object Recognition in Manufacturing Applications

Huitaek Yun,Eunseob Kim,Dong Min Kim,Hyung Wook Park,Martin Byung-Guk Jun 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.4

Feature recognition and manufacturability analysis from computer-aided design (CAD) models are indispensable technologies for better decision making in manufacturing processes. It is important to transform the knowledge embedded within a CAD model to manufacturing instructions for companies to remain competitive as experienced baby-boomer experts are going to retire. Automatic feature recognition and computer-aided process planning have a long history in research, and recent developments regarding algorithms and computing power are bringing machine learning (ML) capability within reach of manufacturers. Feature recognition using ML has emerged as an alternative to conventional methods. This study reviews ML techniques to recognize objects, features, and construct process plans. It describes the potential for ML in object or feature recognition and offers insight into its implementation in various smart manufacturing applications. The study describes ML methods frequently used in manufacturing, with a brief introduction of underlying principles. After a review of conventional object recognition methods, the study discusses recent studies and outlooks on feature recognition and manufacturability analysis using ML.

Design assessment of triangular support bracket for manufacturability

Kim, Yu-Gyeong,Jung, Yung-Jin,Kim, Hyun-Soo,Ahn, Hee-Jae Elsevier 2015 Fusion engineering and design Vol.98 No.-

<P><B>Abstract</B></P> <P>The triangular support is connected structurally and hydraulically with the inner shell of the vacuum vessel and its main role is to keep plasma vertical stability during operational disruptions. Korea is responsible for the procurement of sectors 1 and 6 of the main vessel including triangular support. At present, design review for its fabrication by ITER Korea and Hyundai Heavy Industries, Co., Ltd. is in progress. This paper presents the results on various designs for triangular support bracket in terms of manufacturability considering both easiness of non-destructive evaluation and fabrication efficiency. The several designs are proposed and evaluated under the most critical loading condition using elastic and limit analysis with fatigue evaluation. Consequently, an optimized design for structural safety is determined in accordance with RCC-MR. This result is reconfirmed by cross-checking in comparison with the baseline of integrity that already had been determined by ITER Organization. The design deviation requests of triangular support bracket have been submitted to ITER Organization and Agreed Notified Body for approval, and their verification is currently under discussion.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Various designs for ITER triangular support bracket are proposed in terms of efficient manufacturability. </LI> <LI> An optimized design for structural safety is determined in accordance with RCC-MR. </LI> <LI> This result is reconfirmed by cross-checking in comparison with the IO baseline of integrity. </LI> </UL> </P>

중소 금형업체 협업지원을 위한 핵심 제조역량 평가 모델 개발

신문수,이상일,류광열,주재구 대한산업공학회 2012 산업공학 Vol.25 No.1

Up-to-date enlargement of the scale of global outsourcing has brought about the need of systematic and efficient tools for competitive supplier discovery located in various areas. A web-based business supporting system, referred to as Excellent Manufacturer Scouting System(EMSS), is being developed to serve core business functions including supplier discovery, negotiation, and collaboration between overseas buyers and domestic suppliers throughout the process of supply chain formation. In this paper, a supplier assessment model devoted to evaluation of core manufacturing capability is proposed by targeting small and medium sized mold companies. The assessment model will eventually be loaded to EMSS. Even if many well-designed models for supplier assessment have been presented in literature, most of them limit the evaluation criteria to somewhat general information on a given supplier, such as cost, delivery time, quality, rather than core manufacturing capability itself. This research is pioneering work on supplier assessment from the viewpoint of manufacturability. The proposed assessment model classifies assessment indices into six criteria, which have been drawn by intensive survey and analysis of the mold industry. Actual assessment indices for each criterion are also presented along with an exemplary evaluation result.

Introducing design for selective laser melting in aerospace industry

Roland Stolt,Fredrik Elgh 한국CDE학회 2020 Journal of computational design and engineering Vol.7 No.4

The selective laser melting (SLM) process has created new possibilities for the manufacture of new lightweight jet engine components with lattice structures replacing solid sections. Hopes are to reduce the density of the component and thereby saving weight. To introduce the new manufacturing process, the components need to be redesigned and verified to comply with an array of requirements concerning, for example, strength, aerodynamics, and manufacturing. To find out how a capability of designing and evaluating components for the SLM process can be built into an organization, an interview investigation has been conducted at an aerospace company finding the state of practice in technology and product development. The impact of introducing SLM is thereafter estimated. The result is that introducing a novel manufacturing process will primarily influence the methods used to predict product lifecycle performance. An important finding is that it is currently difficult to include a topology optimization step in the multiobjective design evaluation environment used at the company due to which the complexity would increase significantly.

금속 3D 프린팅을 이용한 복잡형상의 냉각기 설계 제조 전략

이승엽(SeungYeop Lee),양민석(MinSeok Yang),김우성(WooSung Kim),김다혜(DaHye Kim),김건우(KunWoo Kim),이재욱(JaeWook Lee) 한국기계가공학회 2023 한국기계가공학회지 Vol.22 No.5

Metal additive printing technology facilitates unprecedented freedom in the design of mechanical components and has mostly been used to improve their performance. However, the prediction of fabrication failure is equally important in metal additive manufacturing. To address this challenge, this paper presents an integrated strategy that demonstrates the process from design to fabrication of a cooler. This study adopted a multi-fidelity surrogate model and a supporting effect-based prediction algorithm to analyze the geometry of coolers for additive manufacturing. The original geometry was modified based on the prediction results and fabricated using the laser powder bed fusion method. The internal space of the modified cooler design was verified using computed tomography scanning, which revealed no defects. Additionally, the fabricated cooler demonstrated a notable improvement, exceeding 60%. This study demonstrated an effective approach for designing and fabricating metal-additive-printed components, considering both functional requirements and fabrication constraints, which can be widely applied in various fields where performance and reliability are paramount.

영구자석 형태에 따른 소형 풍력발전기의 코깅 토크 개선에 관한 연구

강준호,김정원,윤인열,안정호,원성홍,이주,김현우 대한전기학회 2023 전기학회논문지 Vol.72 No.8

In general, the cogging torque generated in the wind turbine of PMSG (Permanent Magnet Synchronous Generator) acts as a brake and disturbs the operation of generator. In order to drive in light wind, the cogging torque must be small. In this paper, a study was conducted to reduce the cogging torque of PMSG. In general, cogging torque can be reduced through magnet shaping such as tapering. However, the magnet shaping work of the curve is not good considering manufacturability. Therefore, a comparison was conducted according to the permanent magnet shape of ring type and bar type. For the bar type, the characteristics according to the pole slot combination were confirmed. After reviewing the characteristics according to the design variables that affect the cogging torque, optimization was performed through RSM (Response Surface Method). The basic model and optimal model were compared through FEA(Finite Element Analysis).

Parametric Surface Defined on Parallelogrammic Domain and its Properties

FAN Shuqian,ZOU Jinsong,SHI Mingquan (사)한국CDE학회 2013 한국CAD/CAM학회 국제학술발표 논문집 Vol.2010 No.8

As essential components of many mechanical systems, tooth geometrical properties of spiral bevel gears greatly influence on the kinematic and dynamic behaviors of mechanical systems. Logarithmic spiral bevel gears show unique advantage in transmission due to their constant spiral angle property. However, mathematical model suitable for accurate digital modeling, differential geometrical characteristics and related contact analysis methods of tooth surface have not been deeply investigated, since such gears are not convenient to traditional cutting manufacture in gear industry. An accurate mathematical modeling of the tooth surface geometry for logarithmic spiral bevel gears is developed, based on the basic gearing kinematics and spherical involute geometry along with the tangent planes geometry. Actually, the tooth surface is a parametric surface defined on parallelogrammic domain. Then, an equivalence proof of the tooth surface geometry is given in order to greatly simplify the mathematical model. As major factors affecting lubrication, surface fatigue, contact stress, wear and manufacturability of gear teeth, differential geometrical characteristics of the tooth surface is summarized employing classical fundamental forms. By using mentioned geometrical properties, manufacturability and its limitation of logarithmic spiral bevel gears is analyzed using precision forging and multi-axis freeform milling, instead of classical cradle-type machine tools based milling or hobbing. Geometry and manufacturability analysis result shows that logarithmic spiral gears have many application advantages, but many urgent issues such as contact tooth analysis for precision plastic forming and multi-axis freeform milling should be further solved.

Parametric surface and properties defined on parallelogrammic domain

Fan, Shuqian,Zou, Jinsong,Shi, Mingquan Society for Computational Design and Engineering 2014 Journal of computational design and engineering Vol.1 No.1

Similar to the essential components of many mechanical systems, the geometrical properties of the teeth of spiral bevel gears greatly influence the kinematic and dynamic behaviors of mechanical systems. Logarithmic spiral bevel gears show a unique advantage in transmission due to their constant spiral angle property. However, a mathematical model suitable for accurate digital modeling, differential geometrical characteristics, and related contact analysis methods for tooth surfaces have not been deeply investigated, since such gears are not convenient in traditional cutting manufacturing in the gear industry. Accurate mathematical modeling of the tooth surface geometry for logarithmic spiral bevel gears is developed in this study, based on the basic gearing kinematics and spherical involute geometry along with the tangent planes geometry; actually, the tooth surface is a parametric surface defined on a parallelogrammic domain. Equivalence proof of the tooth surface geometry is then given in order to greatly simplify the mathematical model. As major factors affecting the lubrication, surface fatigue, contact stress, wear, and manufacturability of gear teeth, the differential geometrical characteristics of the tooth surface are summarized using classical fundamental forms. By using the geometrical properties mentioned, manufacturability (and its limitation in logarithmic spiral bevel gears) is analyzed using precision forging and multiaxis freeform milling, rather than classical cradle-type machine tool based milling or hobbing. Geometry and manufacturability analysis results show that logarithmic spiral gears have many application advantages, but many urgent issues such as contact tooth analysis for precision plastic forming and multiaxis freeform milling also need to be solved in a further study.

Cell Manufacturability toward Regenerative Medicine

Masahiro KINO-OKA 한국생물공학회 2019 한국생물공학회 학술대회 Vol.2019 No.10