Manufacturing Characteristics Research Articles

Changing Butterfly: a Large 3D Printing Work Based on Structural Mechanics

How to realize mechanical butterfly-like shell and design efficient construction details for resembling, posed problems and challenges to the design and construction of a large 3D printing work. Firstly, through analysis of the synergetic mechanism of butterfly-like morphology and structural mechanic of Hypar shell, digital design methods and adjusting modes were well studied. Secondly, based on the features of additive manufacturing, adaptive methods of unit division and construction were proposed and discussed. Moreover, changing modes of lights were tested through the combination of photoelectric numerical control and corresponding details design. As a result, not only the construction of 3D printing work of large scale butterfly-like shell, but also more than 100 new changing patterns of lights were realized.

ОСОБЕННОСТИ ТЕХНОЛОГИИ ПОЛУЧЕНИЯ ГРАНУЛ ШТАМПОВОГО СПЛАВА НА ОСНОВЕ ХРОМА

ОСОБЕННОСТИ ТЕХНОЛОГИИ ПОЛУЧЕНИЯ ГРАНУЛ ШТАМПОВОГО СПЛАВА НА ОСНОВЕ ХРОМА

Unclonable Optical Fiber Identification Based on Rayleigh Backscattering Signatures

We report a concept of using Rayleigh backscattering signature based unclonable optical fiber identification (OFID) for security-based applications. Due to the inherent manufacturing features of optical fibers, the random Rayleigh backscattering pattern within an optical fiber can be used for identification. We also experimentally demonstrated the OFID idea. Cross correlation in the spatial domain and encoding techniques are applied to verify the authenticity of OFID. Also, it has been demonstrated that the proposed OFID device can survive the high-temperature harsh environment. This robust, reliable, and flexible OFID method has great potential for a variety of applications, such as security, recognition, encryption, identification, and authentication.

Microstructural and Mechanical Implications of Microscaled Assembly in Droplet-based Multi-Material Additive Manufacturing.

To reveal the potential and limits of multi-material three-dimensional (3D) printed parts in droplet-based additive manufacturing, a study combining tensile experiments and 3D imaging technique is proposed. A polymeric composite structure made of acrylonitrile butadiene styrene and thermoplastic polyurethane is manufactured using a two extrusion head printer. The quality of the interface between the two thermoplastics is quantified by adjusting the number of intertwining droplets at the interface. Tensile experiments assisted with digital image correlation are performed with two-interface orientation to discriminate shearing and traction at the interface. The 3D imaging results, which are based on X-ray micro-tomography, show the distinct features of droplet-based additive manufacturing in terms of porosity content and connectivity. Interface properties are found to control, in an incomparable way, the mechanical response. It is found that the interface quality is determinant for enhancing the ultimate performance whereas the interface orientation is found to be the perfect leverage for varying the slope of the linear part.

The role of wearable devices in meeting the needs of cloud manufacturing: A case study

Cloud manufacturing is a service-oriented, customer-centric and demand-driven process with well-established industrial automation. Even though, it does not necessarily mean the absence of human beings. Due to products and their corresponding manufacturing processes becoming increasingly complex, operators' daily working lives are also becoming more difficult. Enhanced human-machine interaction is one of the core areas for the success of the next generation of manufacturing. However, the current research only focuses on the automation and flexibility features of cloud manufacturing, the interaction between human and machine and the value co-creation among operators is missing. Therefore, a new method is needed for operators to support their work, with the objective of reducing the time and cost of machine control and maintenance. This paper describes a practical demonstration that uses the technologies of the Internet of things (IoT), wearable technologies, augmented reality, and cloud storage to support operators' activities and communication in discrete factories. This case study exhibits the capabilities and user experience of smart glasses in a cloud manufacturing environment, and shows that smart glasses help users stay productive and engaged. Cloud manufacturing is a business strategy towards services, customers, and demands.Enhanced human-machine interaction is the success of the next generation of manufacturing.Wearable devices and other related technologies are used to support communication.

Finite element simulation and experimental validation of distortion and cracking failure phenomena in direct metal laser sintering fabricated component

A new one-way coupled thermal-mechanical finite element based model of direct metal laser sintering (DMLS) is developed to simulate the process, and predict distortion and cracking failure location in the fabricated components. The model takes into account the layer-by-layer additive manufacturing features, solidification and melting phenomena. The model is first validated using experimental data, then model is applied to a DMLS fabricated component. The study shows how the stress distribution at the support-solid interface is critical to contributing to cracking and distortion. During the DMLS process, thermal stress at the support-solid interface reaches its maximum during the printing process, particularly when the first solid layer is built above the support layer. This result suggests that cracking at the interface may occur during the printing process, which is consistent with experimental observation. Using a design parametric study, a thick and low-density porous layer is found to reduce residual stress and distortion in the built component. The developed finite element model can be used to future design and optimize DMLS process.

Extracting features for manufacture of parts from existing components based on combining additive and subtractive technologies

The development of additive manufacturing (AM) technology provides the possibility of producing complex parts (including internal complex features) that are difficult to manufacture by machining. However, AM technologies also have some limitations, such as low-dimensional accuracy and long production times. Recently, combining additive manufacturing technology with CNC machining is gaining significant attention. This combination not only takes advantages of individual techniques, but also minimizes their disadvantages. In this paper, taking into account consolidated benefits of such technique combination, an alternative remanufacturing strategy is proposed. The strategy allows end-of-life parts (or existing parts) to be reused directly for manufacture of new parts (or final parts) without involving the material recycling stage. In addition, the final part is intended for another product, namely the existing part has a new life and new usage in its life cycle. To achieve the geometry and quality of final part, a sequence of additive, subtractive manufacturing and inspection operations will be generated. For this purpose, additive manufacturing features and machining features are first identified and extracted from the available information of the existing and final parts. This paper particularly focuses on a feature extraction approach, which is developed using the knowledge of additive manufacturing and CNC machining processes, technological requirements, and available resources. The major criteria and constraints have been defined and applied during the feature extraction process. The extracted features and their relationships will be used as the inputs for designing the process planning. Finally, a case study is used to illustrate the proposed approach.

Melt-pool motion, temperature variation and dendritic morphology of Inconel 718 during pulsed- and continuous-wave laser additive manufacturing: A comparative study

Pulsed-wave laser additive manufacturing offers a number of advantages, such as a lower heat accumulation, a higher cooling rate, finer microstructures and improved mechanical properties over continuous-wave laser additive manufacturing. However, how pulsed laser acts on the melt pool motion, thermal field and hence microstructure is not clear. In this work, a three-dimensional transport model utilizing the level set method is developed to simulate the transient melt pool motion, heat/mass transfer and fluid flow for pulsed-wave laser additive manufacturing. A boundary restriction on the fluid velocity along the liquid/gas interface is employed to confine the liquid flow within the melt pool. The simulated melt pool geometry and temperature are compared with experimental measurements. Moreover, melt pool geometry/motion, temperature variation, and their influence on the microstructure of fabricated samples using both pulsed- and continuous-wave lasers are analyzed. It is found that pulsed-wave laser additive manufacturing features a rounder shaped melt pool, a periodically heartbeat-like motion of the melt pool and a doubled cooling rate. The higher tilt angle of the solidification front results in a dendrite growth direction more tilted to the laser scanning direction and the higher cooling rate results in finer columnar dendrites.

Feature recognition from mesh models

In this paper, we propose a methodology for manufacturing feature recognition from a segmented triangulated mesh model. Proposed methodology has two phases, segment preprocessing and feature recognition. Input to the algorithm is triangulated mesh model which is simplified by segmenting the mesh model into high level regions approximated by a simple primitive such as planes, sphere and cylinders. In segment preprocessing phase, we gather adjacency information related to each identified primitive. For each feature to be identified, feature rules are defined using geometric properties of approximated primitives. Finally, feature recognition phase checks if any of the connected set of primitives satisfy the feature rules and highlights the recognised feature. At present, feature recognition is restricted only to simple features composed of plane primitives such as pocket, step, slot and cylindrical primitive such as holes. Given a segmented mesh model as an input, the algorithm automatically recognises different manufacturing features present in model. This extracted features information then can be used for downstream CAD/CAM application such as process planning, cost estimation and generating feature tree.

Feature recognition from mesh models

In this paper, we propose a methodology for manufacturing feature recognition from a segmented triangulated mesh model. Proposed methodology has two phases, segment preprocessing and feature recognition. Input to the algorithm is triangulated mesh model which is simplified by segmenting the mesh model into high level regions approximated by a simple primitive such as planes, sphere and cylinders. In segment preprocessing phase, we gather adjacency information related to each identified primitive. For each feature to be identified, feature rules are defined using geometric properties of approximated primitives. Finally, feature recognition phase checks if any of the connected set of primitives satisfy the feature rules and highlights the recognised feature. At present, feature recognition is restricted only to simple features composed of plane primitives such as pocket, step, slot and cylindrical primitive such as holes. Given a segmented mesh model as an input, the algorithm automatically recognises different manufacturing features present in model. This extracted features information then can be used for downstream CAD/CAM application such as process planning, cost estimation and generating feature tree.

Optimisation of Additive Manufactured Sand Printed Mould Material for Aluminium Castings

The sand casting process is utilised for over 70% of all castings, the traditional this process requires a disposable sand mould, A pattern the shape of the product to be manufactured, plus manufacturing features is used to create the cavity. Additive Manufacturing processes have been used to generate the sand mould tools directly without patterns, hence reducing the lead time and manufacturing design constraints. This paper focuses on optimising the characteristics of the 3D Sand Printing process to traditional produced Furan mould tools, cumulating with an automotive turbo charger case study, to validate the build parameters optimisation process.

Introducing manufacturing features into numerical modeling of hypervelocity impact damage of composite pressure vessels

Composite pressure vessels are extensively used in unmanned spacecraft systems due to high specific strength of composites, which provides higher mass savings as compared to metallic vessels. The most common example is their use as liquid propellant tanks. Being a part of spacecraft, composite vessels are exposed to space environment, and therefore, may be subjected to hypervelocity impacts (HVI) by orbital debris or micrometeoroids. This paper analyzes the manufacturing features such as filament winding pattern and defects of fabrication that may influence the response of composite pressure vessels to HVI, and discusses the ways to introduce those features into the numerical modeling.

Technical procedure features of nickel dry-powder developer manufacturing by method of plasma-electrolytic dispergating

The following work describes means of nickel dry-powder developer manufacturing by plasma-electrolytic dispergating. For that purpose, a plasma-electrothermic device was developed that allows to manufacture dry-powders with wide range of parameters. Technical conditions for nickel dry-powder developer manufacturing by method of plasma-electrolytic dispergating were defined. By factorial design method regression equations were obtained, that make it possible to plan the process of dry-powders manufacturing with set average particle size and set manufacturing process rate. The described means allows to manufacture nicol dry-powder developer with a particle size of aprox. 100 nm.

Combining Extended Imperialist Competitive Algorithm with a Genetic Algorithm to Solve the Distributed Integration of Process Planning and Scheduling Problem

Distributed integration of process planning and scheduling (DIPPS) extends traditional integrated process planning and scheduling (IPPS) by considering the distributed features of manufacturing. In this study, we first establish a mathematical model which contains all constraints for the DIPPS problem. Then, the imperialist competitive algorithm (ICA) is extended to effectively solve the DIPPS problem by improving country structure, assimilation strategy, and adding resistance procedure. Next, the genetic algorithm (GA) is adapted to maintain the robustness of the plan and schedule after machine breakdown. Finally, we perform a two-stage experiment to prove the effectiveness and efficiency of extended ICA and GA in solving DIPPS problem with machine breakdown.

Revisiting the reasons for contact fatigue defects in rails

As it is known rail is one of the most significant elements of the whole railway construction. Operation under alternating loads from wheels of the rolling stock and different ambient temperatures lead to appearance and development of rail defects and damages. A great variety of operational factors (freight traffic density, axial loads, traffic speeds, track layout and profile) as well as special features of manufacturing and thermal treatment of rails create certain difficulties while identifying reasons for defects and damages. The article deals with an attempt to estimate influence of track layout and lateral forces on appearance of defects and damages in rails on the base of long-term observations of rail operation in Kharkiv Metro. On the basis of the vehicle/track mathematical model which considers structural features of both rolling stock and permanent way in underground systems, the level of lateral forces in curves was calculated. The coefficients of correlation between the track curvature, the level of forces and the amount of defected rails removed were later obtained, that made it possible to determine the dominant factor which may lead to appearance and development of contact fatigue defects in rails laid in curves.

Feature-based control and information framework for adaptive and distributed manufacturing in cyber physical systems

Modern distributed manufacturing within Industry 4.0, supported by Cyber Physical Systems (CPSs), offers many promising capabilities regarding effective and flexible manufacturing, but there remain many challenges which may hinder its exploitation fully. One major issue is how to automatically control manufacturing equipment, e.g. industrial robots and CNC-machines, in an adaptive and effective manner. For collaborative sharing and use of distributed and networked manufacturing resources, a coherent, standardised approach for systemised planning and control at different manufacturing system levels and locations is a paramount prerequisite.In this paper, the concept of feature-based manufacturing for adaptive equipment control and resource-task matching in distributed and collaborative CPS manufacturing environments is presented. The concept has a product perspective and builds on the combination of product manufacturing features and event-driven Function Blocks (FB) of the IEC 61499 standard. Distributed control is realised through the use of networked and smart FB decision modules, enabling the performance of collaborative run-time manufacturing activities according to actual manufacturing conditions. A feature-based information framework supporting the matching of manufacturing resources and tasks, as well as the feature-FB control concept, and a demonstration with a cyber-physical robot application, are presented.

Manufacturing knowledge management based on STEP-NC standard: a Closed-Loop Manufacturing approach

The paper presents a proposal to ensure Closed-Loop Manufacturing from CNC machines to CAM systems. The main goal is to manage knowledge from the CNC machine and to reuse it in the CAM system. This proposal aims to help CAM programmers for programming new machining sequences by choosing the best CNC machines parameters. The main contribution of this paper focuses on how to provide guidelines extracted from past CNC programs to the CAM programme for future cases. Although STEP-NC standard enhances bidirectional exchanges in the digital chain, from CAD systems to CNC machines, it does not allow the management of manufacturing knowledge. To achieve the information feedback from CNC machine to CAM system, Closed-Loop Manufacturing approach sets up a manufacturing loop using PLM systems supported by OntoSTEP-NC – an ontology based on STEP-NC. Centred on the Manufacturing Process Management platform Closed-Loop Manufacturing is a three-step process: (1) capitalisation of cutting parameters, the manufacturing features and the material to fill the Manufacturing Process Management database, (2) validation of last machining sequences and (3) manufacturing feature recognition to have the most relevant information integration from the Manufacturing Process Management in the CAM programming stage.

Developing of Integrated Process Planning System for Flexible Manufacturing Environment

Recently, manufacturing systems are striving for an integrated manufacturing environment. The main aim of this research is to propose methodology and develop a system for generating flexible process plan according to Non-linear process planning approach (NLPP) which is based on a shop floor condition named flexible process plans for all parts before entering the shop floor. Four types of flexibility have been considered which can be related with the part manufacturing. Firstly, sequencing flexibility indicate to the possibility of the sequence interchanging in which required manufacturing operations are performed. Secondly, processing flexibility is refers to the possibility of producing the same manufacturing feature with alternative processes. Thirdly, machine tools flexibility is determined by the possibility of performing an operation on more than one machine and the last is cutting tools flexibility which refers to the possibility of producing the manufacturing feature with alternative cutting tool, the researcher creates mathematical model for each activity of process planning to provide mathematical solution for each one. The developed system basically consists of two modules; firstly, Product design module adopted to define design; secondly process planning module divided into five sub-modules: machining sequence, process selection, machine tools selection, cutting tools selection and machining time sub-modules.

Design synthesis of machining systems using co-platforming

Modern manufacturing environment is characterized by frequent product design changes in order to satisfy evolving customer requirements. Various strategies are implemented in order to efficiently manage the consequences arising from the product design changes starting from product design to planning and manufacturing. This paper focuses on synthesizing manufacturing system using the co-platforming concept which maps product platform features and components to the manufacturing system candidate platform machines. A matrix-based mapping model is proposed in order to determine the candidate platform and non-platform machines. Product-related characteristics including manufacturing features, feature orientation, dimensional and geometrical tolerance, cutting power requirements, workpiece volume and surface finish are considered. Characteristics of machines in the manufacturing system include machining axes, accuracy, working envelop and available power. A case study adopted from an automotive engine cylinder block manufacturer is used for demonstrating synthesizing manufacturing systems, based on co-platforming, which are capable of adapting to new products variants without changes to the platform machines. This prolongs the life of the manufacturing system and reduces costs associated with retooling and replacing it.

Service-evaluation-based resource selection for cloud manufacturing

With the development of cloud computing, increasing attention has shifted from traditional manufacturing toward cloud manufacturing. The distinguishing feature of cloud manufacturing is that the resource designated for a given manufacturing service is always massive, complex, and heterogeneous. Cloud manufacturing also involves a high degree of user participation and user diversity. This article presents a method of resource selection based on service evaluation, which combines predictive evaluations and recommended evaluations. Predictive evaluations are based on the user’s historical evaluations of a given service, and these evaluations may be weighted differently depending on the time when the service occurred. Recommended evaluations are given by recommenders who are selected by a two-step process. These evaluations are weighted according to their similarities and objectivities. The results of numerical experiments show that the proposed method performs better than previous methods.