Manufacturing Characteristics Research Articles

Large Bandgap Shrinkage from Doping and Dielectric Interface in Semiconducting Carbon Nanotubes.

The bandgap of a semiconductor is one of its most important electronic properties. It is often considered to be a fixed property of the semiconductor. As the dimensions of semiconductors reduce, however, many-body effects become dominant. Here, we show that doping and dielectric, two critical features of semiconductor device manufacturing, can dramatically shrink (renormalize) the bandgap. We demonstrate this in quasi-one-dimensional semiconducting carbon nanotubes. Specifically, we use a four-gated device, configured as a p-n diode, to investigate the fundamental electronic structure of individual, partially supported nanotubes of varying diameter. The four-gated construction allows us to combine both electrical and optical spectroscopic techniques to measure the bandgap over a wide doping range.

Microstructural characterization of additively manufactured multi-directional preforms and composites via X-ray micro-computed tomography

Additive manufacturing features “direct” and “layer-by-layer” fabrication and has significantly facilitated the microstructural design and fabrication of a wide range of highly complex parts. To enable the application of additive manufacturing in major industries and composites, it is necessary to evaluate the microstructural features of additively manufactured parts. Among the various advanced characterization techniques, X-ray micro-computed tomography (μ-CT) showed unique advantages as a high resolution, nondestructive and 3D visualization and measurement technique for material characterization. In the research reported in this article, we have fabricated an array of multi-directional preforms and composites and have characterized their microstructural features via X-ray μ-CT. First, a solid specimen as well as 3D orthogonal and 3D braided preforms have been fabricated using fused filament fabrication (FFF) and inspected with X-ray μ-CT. Then, the fabricated preforms have been infused with silicone matrix and the multi-directional preforms and composites have been tested in compression at different strain levels, to reveal their damage evolution under compressive loading. The preliminary effort made in this research demonstrates the feasibility of characterizing microstructure of additively manufactured parts via X-ray μ-CT technique and enables an investigation of the microstructural features and damage evolution of multi-directional preforms and composites.

Microstructural design and additive manufacturing and characterization of 3D orthogonal short carbon fiber/acrylonitrile-butadiene-styrene preform and composite

In contrast to conventional preforming techniques, additive manufacturing features direct and layer-by-layer fabrication, which provides viable new capabilities for the fabrication of reinforced composites. In this article, we explore the microstructural design as well as additive manufacturing and characterization of 3D orthogonal, short carbon fiber/acrylonitrile-butadiene-styrene (ABS) preforms and composite. First, an array of 3D orthogonal preforms is designed based on topological consideration and validated by fused filament fabrication of pure ABS wire; high fidelity between models and preforms is accomplished. Then, short carbon fibers are introduced into the designed 3D orthogonal preforms as reinforcement, using a short carbon fiber/ABS wire. Lastly, the compressive behavior of a 3D orthogonal, short carbon fiber/ABS preform and that of its silicone infused composite are characterized. The preform design methodology developed in this research as well as the preliminary effort made in composite fabrication and characterization demonstrates the feasibility of additive manufacturing of 3D orthogonal preform based fiber composites.

A robust optimization model for cellular manufacturing system into supply chain management

In this paper, a new mathematical model is presented for a cellular manufacturing system into supply chain design with labor assignment. This paper considers important manufacturing features thoroughly such as multiple plant locations, multi-market allocations with production planning and various part mix. The proposed model aims at minimizing the total cost of holding, inter-cell material handling, external transportation, fixed cost for producing each part in each plant, machine and labor salaries. It is assumed that the demands of products are uncertainty in three scenarios: optimistic, pessimistic and normal. Also, a robust optimization approach is then developed to solve the proposed model and find the best solution. The robustness and performance of the proposed model are explained in terms of an industrial case from a typical equipment manufacturer. This case study provides the researchers and practitioners to better understand the importance of designing robust optimization and cell formation in the supply chain management from a practical point of view.

Ubiquitous manufacturing: Current practices, challenges, and opportunities

Ubiquitous manufacturing (UM) features a “design anywhere, make anywhere, sell anywhere, and at any time” paradigm that grants factories an unlimited production capacity and permanent manufacturing service availability. However, the research and applications of UM have been limited thus far to in-factory operations or logistics. For this reason, this study reviews the current practices of UM, discusses the challenges faced by researchers and practitioners, and determines potential opportunities for UM in the near future. Finally, we conclude that the success of UM depends on the quality of the manufacturing services deployed, and that UM is a realizable target for Industry 4.0.

Closed-loop Manufacturing, a STEP-NC Process for Data Feedback: A Case Study

This article exposes a solution to ensure Closed-Loop Manufacturing from CNC machines to CAM systems. The main goal is to capitalize knowledge from the CNC machine and to reuse it in the CAM system. This proposal aims to help CAM programmers in making choices for planning new machining sequences.The STEP-NC standard allows bi-directional exchanges in the digital chain – from CAD systems to CNC machines. Unfortunately, STEP-NC standard does not allow having a traceability of machining program. To achieve the information feedback from CNC machine to CAM system, Closed-Loop Manufacturing sets up a manufacturing loop using PLM systems. This solution is based on OntoSTEP-NC, an ontology based on STEP-NC which provides trades between Product Data Management, Manufacturing Process Management and Enterprise Resource Planning. As a solution OntoSTEP-NC supports data extraction from CNC machines, and relevant information reinjection to CAM systems. Closed-Loop Manufacturing is a three steps process: (1) Manufacturing feature recognition to have the most relevant information reinjection from the Manufacturing Process Management database in the CAM programming stage, (2) validation of machining sequences before capitalizing them, (3) capitalization of cutting parameters, the manufacturing feature and the material to fill the Manufacturing Process Management database. This process will help CAM programmers making choices for cutting conditions based on company good practices.A case study has been chosen to test Closed-Loop Manufacturing concepts. The case study is divided into three scenarios aiming at testing first the “reuse phase” including manufacturing feature recognition for the reinjection of relevant information. The third scenario tests the “capitalization phase” and the ability of the system to detect the changes made by the operator directly on the CNC machine. This paper also details the trades between the CAM systems and OntoSTEP-NC by focusing on extracted data and the way the information is capitalized into the Manufacturing Process Management database. It also details the queries addressed to the Manufacturing Process Management database to send the most relevant information.

Радиационно стойкая фотоструктура на основе Cr/In2Hg3Te6 для диода Шоттки

Ge, Si, InGaAs, GaInAsP photodiodes are used as optical radiation receivers and function in a spectral range of transparency of quartz fiberglass. For the optical systems operated in the increased radioactivity the photodetectors’ application on In2Hg3Te6 crystal base characterized by a photosensitivity in the spectral range of 0,5—1,6 mm and also by increased radiation resistance to alpha, beta and gamma radiation is most acceptable. Schottky photodiode structure was designed on the base of this semiconductor formed by a modified floating zone recrystallization technique where the sedimentation effect was leveled. It consists of n-In2Hg3Te6 substrate and deposited by cathode sputtering Cr barrier layer of thickness within a range 10—11 nm choice of Cr is determined by its optimal optical, electric and adhesive features in high quality radiation-resistant photodiode structures manufacturing. Indium and nichrome are used as ohmic contacts. The barrier structures have the contact area of 1,13 mm2 with photo response of 0,6—1,6 mm at the maximal sensitivity 0,43 A/W on the wavelength l,55 mm. Reverse dark current of these structures do not exceed 4 mA at the bias of 1 V (T=295 K), and the potential barrier height is equal to 0,41 eV. The tests of radiation resistance of these structures demonstrated their ability to function at doses of 2•108 rem without evident parameters changes. This allows using them in practical aims in the conditions of high radiation.

3D Metal Printing Technology

Abstract: 3D Printing or Additive manufacturing is a novel method of manufacturing parts directly from digital model by using layer by layer material build-up approach. This tool-less manufacturing method can produce fully dense metallic parts in short time, with high precision. Features of additive manufacturing like freedom of part design, part complexity, light weighting, part consolidation and design for function are garnering particular interests in metal additive manufacturing for aerospace, oil & gas, marine and automobile applications. Powder bed fusion, in which each powder bed layer is selectively fused by using energy source like laser, is the most promising additive manufacturing technology that can be used for manufacturing small, low volume, complex metallic parts. This review presents overview of 3D Printing technologies, materials, applications, advantages, disadvantages, challenges, economics and applications of 3D metal printing technology.

Lead ferroniobat ceramic and films structures manufacture features and dielectric characteristic

Lead ferroniobat lithium doped ceramic samples have been prepared and investigated. Ceramic high quality has confirmed by obtained structural and electro physical properties. The attempt to thin films synthesis by deposition in a capacitive radiofrequency discharge from ceramic target is described; MgO substrate and pure oxygen ambient have been used. Synthesized films structure properties have been investigated, X-ray pattern with lead ferroniobat weak peak and cross-section SEM-image are presented.

Cellular Manufacturing Systems: Organization, Trends And Innovative Methods

Montajda kullanilan parcalardaki degistirilebilirlik, modern imalatin belirgin bir niteligi olmustur. Gunumuz insanlarina doyum saglayacak muazzam bir uretim gucune de yine bu kavram sayesinde erisilebilmistir. Ancak bu kavramdan yararlanma gayretleri, bir ikilemi de beraberinde getirmistir. Bir yanda degistirilebilirlik sayesinde yuksek verimlilikle ama son derece sinirli tipte urun ureten ve esnek olmayan seri uretim hatlari diger yanda da cesit cesit urunu uretebilen esnek ama verimsiz parti tipi uretim sistemleri ortaya cikmistir. Her iki uretim tipinin ustun yanlarini birlestirecek care de, uzun bir sureden beri Hucresel Uretim (HU) olarak gorulmustur. Fakat ilk bakista, cok parlak bir dusunce olarak gorunen bu yaklasim da, hicbir zaman kendinden beklenen hizla yayginlasamamistir. Bu makalenin amaci da, buradaki celiskinin kuramsal ve uygulamaya yonelik kaynaklarini irdeleyip, ozellikle bilgisayar gibi araclar ve yapay zekâ gibi yeni tekniklerin saglayacagi olanaklar yaninda isin orgutsel ve toplumsal yonlerini vurgulayarak HU uygulamalarindaki basari duzeyini yukseltebilecek bazi ipuclarini ortaya koymak olmustur.

An overview of the computer-integrated systems and manufacturing technologies of pistons of internal combustion engines

The technological features of manufacture of pistons of internal combustion engines (ICE) taking into account the operational characteristics that form the functional requirements of the piston material are considered. It is shown that the chill casting of pistons is recommended for alloys with a low coefficient of linear expansion, and the liquid forging of pistons is preferable to the hot forging since it allows to obtain defect-free, dense billets with the fine structure of the piston material. For the heavy-loaded diesel engine pistons, chill casting is acceptable, provided the maximum possible porosity prevention in massive parts of castings.For the simulation of the casting processes of ICE pistons, it is advisable to use the LVMFlow package since it is focused on the finite-difference computation algorithms, ensuring stable operation of the computational station at a relatively low consumption of its hardware resources, ease of interface, computation speed and low cost of the software package. For the engineering simulation of the thermal and the stress-strain state of the ICE cast pistons, the ANSYS complex that has a high interaction with existing CAD and CAE systems having full interaction with WorkbenchProducts and well-known ANSYS, as well as a large number of mathematical solvers, allowing to quickly and accurately conduct computations in the WorkbenchProducts can be recommended.

Analysis of film cooling performance of advanced tripod hole geometries with and without manufacturing features

The present study evaluates the film cooling performance of a set of manufacturable tripod hole designs, with and without shaped exits. The tripod holes with realistic manufacturing features included rounded corners at the hole inlet and outlet, as well as a webbing between the tripod holes. Standard cylindrical and shaped cylindrical (10° fan+laidback) holes were also studied for comparative analysis. Transient heat transfer experiments with a mainstream Red≈3200 were conducted on a flat plate test rig. Different hole geometries were tested at equal mass flow rates, corresponding to a range of blowing ratios equal to 0.5, 1.0, and 2.0 for the cylindrical hole. IR (Infrared) thermography was used to evaluate adiabatic film cooling effectiveness, heat transfer coefficient, and the normalized heat flux on the flat surface. Results showed that the presence of rounded corners or webbing did not lower the performance of the tripod cooling holes. Both tripod hole geometries, with and without manufacturing features, yielded higher film cooling effectiveness compared to the cylindrical holes and slightly higher effectiveness than the shaped holes, while consuming 50% less coolant when operating at the same blowing ratio. The heat transfer coefficient measurements and the overall heat flux ratios further corroborated the thermal advantages of the tripod hole design over traditional cylindrical and shaped holes.

The powers of the European Constitutional Courts to hear cases on the constitutionality of regulations at the request of the courts and their corresponding features of manufacture

The article analyzes the powers of the constitutional courts of four leading European countries: Germany, France, Italy and Spain to consider cases on the constitutionality of regulations at the request of the courts, as well as the corresponding features of the production. Reveals the nature of this type of constitutional proceedings. It is proved that the adversarial principle is applied only partially, and in some cases does not apply.

Two bounds for integrating the virtual dynamic cellular manufacturing problem into supply chain management

This paper presents a new mathematical model for integrating the virtual dynamic cellular manufacturing system into supply chain management with an extensive coverage of important manufacturing features. The considered model regards multi-plants and facility locations, multi-market allocation, multi-period planning horizons with demand and part-mix variation, machine and labor time-capacity, labor assignment, training and purchasing or selling of new machines for an increased level of plant capacity. The main constraints are market demand satisfaction in each period, machine and labor availability, production volume for each plant and the amounts allocated to each market. To validate and verify the proposed model is explained in terms of an industrial case from a typical equipment manufacturer. Some of the hard constraints of the proposed model are relaxed in order to obtain a lower bound on the objective function value. In fact, the number of machines and workers allocated to each cell are restricted to yield feasible solutions and tight upper bounds on the objective values for medium size instances in a shorter time. The relaxed model yields tight lower bounds for medium instances in a reasonable computational time. Furthermore, a Benders decomposition is developed for solving the upper bounding model.

An approach to mapping machining feature to manufacturing feature volume based on geometric reasoning for process planning

Efficient construction in three-dimensional working procedure model has an important effect on the efficiency and quality of machining process planning. This article proposes an algorithm to mapping machining features to manufacturing feature volumes from B-rep of mechanical part, and then, the working procedure models are generated. The mapping strategy is performed in three steps. In the first step, three types of machining features, such as depression feature, protrusion feature and transition feature, are introduced. In the second step, the edges of the chosen seed face and its neighboring faces are searched in order to generate the machining feature faces. The last step applies a closure to the machining feature faces to generate a compact solid by applying additional neighboring faces and their extensions. Then, the working procedure models are formed by combining the mapped manufacturing feature volumes with the final parts model. Compared with the existing working procedure model’s generation methods, this approach can avoid the unnecessary conversions from the engineering drawing to three-dimensional process models and from the machining knowledge to the modeling knowledge, which can greatly reduce the planning time on modeling. To validate the feasibility and validity of this approach, two machined parts with complex machining features are tested in the developed prototype computer-aided process planning system.

Revised multi-choice goal programming for incorporated dynamic virtual cellular manufacturing into supply chain management: A case study

In this paper, a bi-objective optimization model is proposed for a dynamic virtual cellular manufacturing system and supply chain design. The presented model considers important manufacturing features thoroughly such as multi-plants and facility locations, multi-markets allocations, multi-period production planning under uncertain demand of products and capacities of resources. The proposed model is converted into an equivalent auxiliary crisp model. Then, to solve the model, a revised multi-choice goal programming approach is applied for finding a favorite solution. The aims of the proposed model are to minimize the total cost of supply chain design which includes holding cost, outsourcing cost, maintenance and overhead cost of machines, fixed cost, external transportation cost and minimizing the total number of exceptional elements and movements of the labors between active plants. The Computational results are explained in terms of a real case study as well as the validity of the proposed model solution method.

Nanoscale Magnification and Shape Control System for Precision Overlay in Jet and Flash Imprint Lithography

Jet and flash imprint lithography steppers have demonstrated unprecedented capability for patterning of sub-25-nm features for semiconductor manufacturing. A critical requirement for such patterning is the ability to overlay one layer of a device to a previously printed layer. In this paper, the design and development of a nanoprecision mask magnification/shape control system (MSCS) for the unique requirements of imprint-based overlay is presented. Imprint specific topics such as in-liquid overlay and distortions, and on-tool overlay metrology are discussed. The MSCS presented here has demonstrated 10-nm mix and match overlay (mean + 3 sigma) capability that approaches performance of state-of-the-art photolithography tools.

A Methodology to Recognize Manufacturing Features of Prismatic Parts from STEP AP 203 File

To enhance the interoperability and integration of CAD/CAM system, a generic feature recognition system will be needed incompliant with Standard for Exchange of Product model data (STEP) neutral file for seamless manufacturing. The main objective of this work is to develop a methodology to recognize manufacturing features of prismatic parts from STEP AP 203 file (i.e. ISO 10303 file), which will recognize all common types of manufacturing features of prismatic parts. In this work a new concept called Object Slicing Approach (OSA)in which an imaginary plane with a specific feature definition will be moved along different axes directions to identify all the manufacturing features of the component. In this approach a STEP AP 203 neutral file (i.e.Configuration controlled 3D design data file) is considered for feature recognition process. This paper covers the literature survey with more emphasis on STEP AP 203 neutral format file. To extract the data from the STEP AP 203 file an interface called Java Standard Data Access Interface (JSDAI) is used. In this work a JAVA programmed system will be developed to identify different manufacturing features form the product model with JSDAI as interface to JAVA program. The effectiveness of the above mentioned approach will be demonstrated by considering examples with different features.

20 лет НАФТА

2014 marked the 20th anniversary of the entry into force of the North American Free Trade Agreement (NAFTA), which created the world’s largest free trade area. Now it links 470 million people producing more than 19 trillion USD worth of goods and services. The article addresses five issues: the international importance of NAFTA; the economic transformation that has occurred in the USA, Canada and Mexico since the advent of the NAFTA; a “thought experiment” on what American, Canadian and Mexican performance might have been without the NAFTA; the detrimental effect of 9/11 on the North American economic integration; and what’s next? At the time of its signing, NAFTA in many ways was considered a “gold standard” in terms of international free trade agreements. For the first time ever a free trade agreement brought together both developed and developing countries. It also broadened the scope of traditional FTAs by embracing services, foreign investments and property rights, and recognized the importance of workers' and environmental rights and issues. In terms of trade and investment NAFTA has been an undisputed success. Canada ranks as the United States’ largest export market, while Mexico is its second-largest export market. Today – thanks to NAFTA – North Americans not only sell more goods to one another, they also make more things together. For every dollar of goods that Canada and Mexico export to the USA, there are 25 cents’ worth of US inputs into Canadian goods and 40 cents’ worth into Mexican ones. Regardless of the impressive economic record, NAFTA has its critics. The agreement has not underwent a major update since its inception in 1994, i.e. prior to the rise of electronic commerce and, digital services, advanced manufacturing and many other innovative features of the global economy. As far as there is no political appetite to update NAFTA directly, indirect route is a subject of wide speculation. Canada, the USA and Mexico are negotiating partners to the Trans-Pacific Partnership and any benefits conferred by the TPP that go further than NAFTA would take precedence. It is assumed that the TPP should help to modernize NAFTA commitments and upgrade the North American trade and investment.

Graph based automatic process planning system for multi-tasking machine

Multi-tasking machine is capable of performing both milling and turning operations, it contributes to highly efficient machining and space conservation. However, prior to machining a lot of lead time is consumed in deciding efficient process plan, and generating machining tool path. Although the current CAM systems are highly integrated, the efficiency of the generated tool path is highly relied on the experience of the CAM programmer. In this research, an automatic process planning system for multi-tasking machine was developed. It is capable of recognizing manufacturing features and deciding efficient process plan from CAD model automatically. In this developed system, the CAD model is described as Attributed Adjacency Graph (AAG), and each feature is defined by AAG and its geometrical properties. Totally 8 milling features and 9 turning features can be recognized. The optimal machining plan is calculated based on machining cost evaluation. In addition, in this research a new method based on subfeature combination is proposed in order to recognize intersecting features. Furthermore, in this research the connection relationship of each feature is classified, and machining priority is assigned to adjacent features. It prevents the time consuming evaluation for checking all possible machining sequences. Finally, according to the experiment results, it is confirmed this developed system is capable of obtaining optimal machining plan properly and rapidly.