Manufacturing Sequence Research Articles

Weld distortion prediction of the ITER Vacuum Vessel using Finite Element simulations

The as-welded surfaces of the ITER Vacuum Vessel sectors need to be within a very tight tolerance, without a full-scale prototype. In order to predict welding distortion and optimize the manufacturing sequence, the industrial contract includes extensive computational simulations of the weld processes which can rapidly assess different sequences. The accurate shape prediction, after each manufacturing phase, enables actual distortions to be compared with the welding simulations to generate modified procedures and pre-compensate distortions. While previous mock-ups used heavy welded-on jigs to try to restrain the distortions, this method allows the use of lightweight jigs and yields important cost and rework savings. In order to enable the optimization of different alternative welding sequences, the simulation methodology is improved using condensed computation techniques with ANSYS in order to reduce computational resources. For each welding process, the models are calibrated with the results of coupons and mock-ups. The calibration is used to construct representative models of each segment and sector. This paper describes the application to the construction of the Vacuum Vessel sector of the enhanced simulation methodology with condensed Finite Element computation techniques and results of the calibration on several test pieces for different types of welds.

제품정보관리를 위한 통합적 멀티BOM시스템

Bill of material (BOM), which structurally represents the relation among parts constructing a product, is usually created when enterprises start to develop a new product. And it is shown as various types of BOM according to business needs and usage such as eBOM (engineering BOM), gBOM (green BOM), mBOM (manufacturing BOM), pBOM (process BOM), etc. eBOM, generally called BOM and created in the design stage of the new product, includes the drawing information of parts in the view of product function. eBOM is extended to gBOM adding the material information of parts to cope with international regulations for environment. eBOM is transformed to mBOM, which includes manufacturing sequence of parts and adds some parts required to fabricate parts and to assemble the product. mBOM is also extended to pBOM adding the process information of each part and additional assembly processes. This study introduces the concept of multi-BOM covering eBOM, gBOM, mBOM and pBOM, and proposes an advanced way to manage product data using multi-BOM system. The multi-BOM system proposed is to manage their relations using transformation function of BOM and master information of all BOMs.

Dimensional analysis of a prototype mould-making process for thermoplastic resin transfer moulding

The resin transfer moulding (RTM) process is a low-cost process for the production of parts of composite material. However, the economic convenience is lost when large components should be produced, because of the high tooling cost. The step milling of a resin master and the subsequent deposition of a nickel shell could be a valid alternative for the fabrication of an RTM mould. So far, information about the quality of this method of fabricating RTM moulds is lacking, thus more efforts are needed to quantify the error induced by the manufacturing sequence. In order to control the whole process and to assess the quality of the manufactured part, the dimensional deviation due to single manufacturing steps is evaluated for a reference part. Both traditional pointwise measurements and contactless scanning are used for dimensional inspection.

Organization of structural and technological elements in machine parts to optimize the manufacturing sequence

Organization of structural and technological elements in machine parts to optimize the manufacturing sequence

El concepto de estilo tecnológico cerámico y su aplicación en un caso de estudio: los grupos formativos del oeste de Tinogasta (Catamarca)

Technological style has been regarded as a useful tool for the study of cultural variation patterns and to iden-tify and explore social boundaries through the material record. Technological styles definition involves the iden-tification of existing technical variability within the analyzed sample that results from the different technological choices implemented by the craftsmen during the different steps of the manufacturing sequence. In archaeologi-cal terms the existence of certain attributes of the artifacts that co-varies in time and space imply some kind of relationship between persons who produced and used them. These relationships may include different levels of social interaction that does not necessarily involve co-residence. This work takes the concept of technological style and presents the results of analyses carried out on ceramic samples recovered in different archaeological sites corresponding to pre-estate agricultural societies that developed between 1500 - 1300 BP occupying different environments of western Tinogasta (Catamarca). The results contribute to the definition of the structure of the territory of such societies and are an indicator of the different degrees of interaction of human groups within a social system.

Bronze Age Ceramic Economy: The Benta Valley, Hungary

We describe the Bronze Age ceramic economy of the Benta Valley in Hungary. In the Bronze Age, long-distance trade in metals, metal objects, and other specialty items became central to expansive prestige goods exchange through Europe. Was that exchange in wealth, however, linked to broader developments of an integrated market system? The beginnings of market systems in prehistory are poorly understood. We suggest a means to investigate marketing by studying the changing ceramic economy of a region, rather than at a single site. Analysis of the ceramic inventory collected as part of the Benta Valley Project strongly suggests that, although ceramic production was quite sophisticated and probably specialized, exchange was highly localized (mostly within 10 km) and conducted through personalized community networks. Our ceramic study used three progressively finer-scaled analyses: inventorying ceramic forms and decoration to evaluate consumption patterns, petrographic analysis to describe manufacturing sequences, and instrumental neutron activation analysis (INAA) to describe exchange. We conclude that, based on present evidence, market systems had not developed in Hungary during the Bronze Age.

One-Step Fabrication of Copper Electrode by Laser-Induced Direct Local Reduction and Agglomeration of Copper Oxide Nanoparticle

Copper oxide (CuO) nanoparticle-based organic solutions are highly stable in air as well as cheaper compared to copper (Cu) nanoparticle solutions due to the absence of particle oxidation problems. Laser direct patterning via photothermochemical reaction of the CuO nanoparticles is suggested to efficiently fabricate Cu electrodes. CuO nanoparticles dispersed in ethylene glycol were instantaneously reduced to Cu nanoparticles by intense laser irradiation, and the Cu nanoparticles were simultaneously agglomerated and sintered to form conductors without additional processes. Finally, Cu electrodes with about 10 μm thickness and a specific electrical resistance of 31 μΩ·cm were successfully fabricated on a glass and flexible substrate. Furthermore, the maximum possible patterning rate was discussed in terms of the reduction rate of CuO. This conductor structuring method enables an environmentally friendly and cost-effective process as well as a low-temperature manufacturing sequence to realize large-area, fle...

Pottery-Making in Spanish California: Creating Multi-Scalar Social Identity through Daily Practice

Between 1769 and 1834, the Spanish missions of Alta California were pluralistic communities. Faced with cultural entanglement, residents of particular missions formed communities of practice, out of which a shared social identity may have emerged. This process of colonial identity construction is illustrated by the patterned ways potters at one mission, Mission San Antonio de Padua, constructed Plainwares. Potters within this mission community selected the same local raw materials and fired ceramics in open fires. As potters participated in shared traditions of ceramic production, with regard to these steps in the manufacturing sequence, they may have created a shared social identity. In addition to the creation of a shared community identity, potters may have produced and reproduced other social identities that served to create arenas of division. For example, variability in primary forming techniques may suggest that gender identities were created out of the way some potters, possibly women, hand modeled vessels while others, possibly men, threw vessels on a wheel. Through ceramic production, potters at Mission San Antonio de Padua may have at one scale fostered a sense of belonging to the mission community, but at other scales created arenas for social distinction within the indigenous population.

Integrated Product and Process Control for Sustainable Semiconductor Manufacturing

Semiconductor fabrication is a manufacturing sequence with hundreds of sophisticated unit operations and it is always challenged by strategy development for ensuring the yield of defect-free products. In this paper, an advanced control strategy through integrating product and process control is established. The proposed multiscale scheme contains three layers for coordinated equipment control, process control and product quality control. In the upper layer, online control performance assessment is applied to reduce the quality variation and maximize the overall product performance (OPP). It serves as supervisory control to update the recipe of the process controller in the middle layer. The process controller is designed as an exponentially weighted moving average (EWMA) run-to-run controller to reject disturbances, such as process shift, drift and tool worn out, that are exerted to the operation. The equipment in the process is individually controlled to maintain its optimal operational status and maximize the overall equipment effectiveness (OEE), based on the set point given by the process controller. The efficacy of the proposed integrated control scheme is demonstrated through case studies, where both the OPP (for product) and the OEE (for equipment) are enhanced.

A genetic algorithm-based scheduler for multiproduct parallel machine sheet metal job shop

This paper presents a genetic algorithm-based job-shop scheduler for a flexible multi-product, parallel machine sheet metal job shop. Most of the existing research has focused only on permutation job shops in which the manufacturing sequence and routings are strictly in a predefined order. This effectively meant that only the jobs shops with little or no flexibility could be modeled using these models. The real life job shops may have flexibility of routing and sequencing. Our paper proposes one such model where variable sequences and multiple routings are possible. Another limitation of the existing literature was found to be negligence of the setup times. In many job shops like sheet metal shops, setup time may be a very sizable portion of the total make-span of the jobs, hence setup times will be considered in this work. One more flexibility type arises as a direct consequence of the routing flexibility. When there are multiple machines (parallel machines) to perform the same operation, the job could be routed to one or more of these machines to reduce the make-span. This is possible in situations where each job consists of a pre-defined quantity of a specified product. In other words, same job is quantity-wise split into two or more parts whenever it reduces the makespan. This effectively assumes that the setup cost is negligible. This model has been implemented on a real-life industry problem using VB.Net programming language. The results from the scheduler are found to be better than those obtained by simple sequencing rules.

THE EARLIEST BEAD MANUFACTURE IN THE AMERICAS AT THE PALEO-INDIAN JONES-MILLER SITE, WRAY, COLORADO

ABSTRACTAnalysis of the composition and microstructure of a Paleo-Indian micro-bead fragment from the Jones-Miller bison-kill site in Wray, Colorado, USE, and dated by radiocarbon testing to 10,200 years ago, showed that fine-motor movements were used to execute a sequence of manufacture on a singular bead. The process involved cleaving a soft, bedded oil shale, diagonally scraping a tubular surface and double-drilling a hole. The last operation caused the bead to fracture, after which it was deposited in a hearth. The raw material consists of bedded clay, silt, opal and quartz particles cemented with carbonaceous material. The presence of similar locally available oil shale with opal inclusions indicates that the raw material was acquired near the Jones-Miller site. Because of high cultural value and small size, only non-destructive analytical techniques were used to characterize the bead, including optical microscopy, UV-VIS, PIXE and XRD. Some 50-micron, previously detached particles were tested by SEM-EDS and compared to local clayey materials, both heat-treated and non-heat-treated, to show that no heat treatment sufficient to cause sintering had occurred. A resource survey in the area around the site and 50 miles to the south produced several comparative materials that were tested by the same methods given above as well as the added methods of DTA and refiring tests.

Bronze Age Ceramic Economy: The Benta Valley, Hungary

We describe the Bronze Age ceramic economy of the Benta Valley in Hungary. In the Bronze Age, long-distance trade in metals, metal objects, and other specialty items became central to expansive prestige goods exchange through Europe. Was that exchange in wealth, however, linked to broader developments of an integrated market system? The beginnings of market systems in prehistory are poorly understood. We suggest a means to investigate marketing by studying the changing ceramic economy of a region, rather than at a single site. Analysis of the ceramic inventory collected as part of the Benta Valley Project strongly suggests that, although ceramic production was quite sophisticated and probably specialized, exchange was highly localized (mostly within 10 km) and conducted through personalized community networks. Our ceramic study used three progressively finer-scaled analyses: inventorying ceramic forms and decoration to evaluate consumption patterns, petrographic analysis to describe manufacturing sequences, and instrumental neutron activation analysis (INAA) to describe exchange. We conclude that, based on present evidence, market systems had not developed in Hungary during the Bronze Age.

Nanoparticle Selective Laser Processing for a Flexible Display Fabrication

To demonstrate a first step for a novel fabrication method of a flexible display, nanomaterial based laser processing schemes to demonstrate organic light emitting diode (OLED) pixel transfer and organic field effect transistor (OFET) fabrication on a polymer substrate without using any conventional vacuum or photolithography processes were developed. The unique properties of nanomaterials allow laser induced forward transfer of organic light emitting material at low laser energy while maintaining good fluorescence and also allow high resolution transistor electrode patterning at plastic compatible low temperature. These novel processes enable an environmentally friendly and cost effective process as well as a low temperature manufacturing sequence to realize inexpensive, large area, flexible electronics on polymer substrates.

Optimization of the forming sequence of a threaded insert with groves by means of FEM simulation

In this paper the forging sequence of a new type of threaded insert is investigated by means of FEM simulations and subsequently optimized in order to decrease the number of operation. In fact, if the standard forging sequence of inserts without groves is used, an external heat treatment is usually realized after the product forming thus requiring a further forging operation after the H.T. for grooves formation. A new manufacturing sequence is here proposed and investigated: five forming operations including groves forging are sequentially realized then the complete annealing is realized at the end of the cycle. FEM simulation showed that the material hardening during groove formation strongly influenced the insert deformation during fastening and, in order to shift the annealing treatment at the end of the sequence, the shape of the deformation chamber needs relevant geometry modification. A FEM campaign was therefore performed in order to analyze the behaviour of the insert during the fastening phase on different sheets thickness, following different possible forging sequences. A pre-series of the developed inserts following the optimized sequence is then produced and tested: the grooved inserts properly fastened the required sheets range and the shape of the deformed inserts accurately matched the simulated geometry.

Optimal design of manufacturing chain based on forging for copper alloys, with product properties being the objective function

The design of manufacturing copper alloys is the objective of the paper. The whole manufacturing chain based on forging is considered. Plastometric tests with various preheating schedules were performed, and rheological models dependent on the material structure were developed. Various manufacturing sequences were considered next. Numerical simulations were performed using CAFE model, and a production schedule, which allows achievement of the required properties and minimum tool wear, was selected. Industrial experiments were performed and the designed technology was validated. Experimental results confirmed correctness of the developed technology.

Application of neural network and evolutionary algorithm in operation sequencing using datum hierarchy trees

In manufacturing, the determination of a (near) optimal sequence of machining operations to create a part is a non-trivial task. The paper presents the use of datum hierarchy trees in operation sequencing to ensure the finished part satisfies the design tolerances. Based on this technique, a framework is proposed to automate not only the retrieval of relevant plans for evolving the datum hierarchy tree of a new part, but also the optimisation of the operation sequence subjected to constraints on group cell layout, cut sequence, and machine tolerances. The retrieval process is based on the classification of parts using a back propagation neural network while the operation sequence is optimised using an evolutionary algorithm. Results showed that both geometrical and part features may be needed to assist the categorisation of the parts investigated. The results from a case study using industry parts from an aerospace company revealed the potential practical value of the proposed approach in deriving operation sequence for minimal machine and datum changes, both including and excluding manufacturing sequence constraints imposed by group cell layout.

Ultra high resolution, low temperature, direct metal patterning by selective laser processing of solution deposited metal nanoparticles

AbstractAll-printed electronics is the key technology to ultra-low-cost, large-area electronics. As a critical step in this direction, we demonstrate that femtosecond laser processing (sintering and ablation) of solution deposited metal nanoparticles enables direct metal patterning at low-temperature with ultra high resolution (∼300nm) to overcome the resolution limitation of the current inkjet direct writing processes.This could be explained by the combined effects of novel properties of metal nanoparticles such as melting temperature drop, strong absorption of the incident laser beam at surface plasmon mode, lower conductive heat transfer loss, and the relatively weak bonding between nanoparticles. Local thermal control of the laser sintering process could minimize the heat-affected zone and the thermal damage to the substrate and further enhance the resolution of the process. This local nanoparticle deposition and energy coupling enable an environmentally friendly and cost-effective process as well as a low-temperature manufacturing sequence to realize large-area, flexible electronics on polymer substrates.

Development of a Scalable Synthetic Process for DG-051B, A First-in-Class Inhibitior of LTA4H

DG-051B is a first-in-class small molecule inhibitor of leukotriene A4 hydrolase (LTA4H), currently in Phase II clinical development for the prevention of heart attack. Process optimization led from a linear seven-step synthetic procedure to a convergent four-step manufacturing sequence that has been used to manufacture at 100-kg scale. The entire process can be telescoped due to high conversion reactions, low impurity levels, efficient separations, and a very effective final purification. Two key aspects of the process are: (a) bypassing the isolation of a reactive electrophile by using its aqueous-washed reaction mixture directly into a coupling reaction with a phenoxide nucleophile and (b) modulating the properties of the final product solutions for optimal extraction, purification, and crystallization.

An approach for generating a tasks schedule model in web-based virtual manufacturing system of screw threads

In this paper, several web-based interfaces for user interaction and a task-oriented decision approach are proposed to build a tasks schedule model and then display the manufacturing process in a virtual environment, which is created by a geometric virtual-reality-based visualization technology for screw threads generation. The proposed tasks schedule model consists of four types of objects: virtual component, state manager, transfer operator, and flow controller. The virtual component has a geometric model with kinematics and their attributes. To control the geometric model, a component controller which models the logical aspects of a component is used. The component controller should be able to implement component-level orders by operating the geometric model. For the fidelity of the tasks schedule model, a transfer operator has a set of component-level command imitating the physical mechanism of a transfer. As a result, more accurate simulation results can be expected. The flow controller makes decisions on friable transfers based on decision parameters, which are maintained by the state manager. To have better structure and easier implementation, a virtual manufacturing platform can be modeled in a hierarchical and modular manner as an integrated system consisting of a product design suite, a web interface module, and a visualization module. Meanwhile, it provides a solution of learning of manufacturing sequences, cost effective, platform independent, and sharing visualized information over the internet for virtual manufacturing. Finally, the tasks schedule model has been implemented with an example in screw threads generation.

Use of a new methodology for prediction of weld distortion and residual stresses using FE simulation applied to ITER vacuum vessel manufacture

The ITER VV Sectors have to be manufactured to extremely tight tolerances, without the production of a prototype to establish the welding distortions. It is thus necessary to develop a (computationally) successful methodology for modelling weld process in order to predict welding distortion and residual stresses. Further, in order to optimise the manufacture sequence and method, the model should be able to rapidly assess the effect of using different sequences. Once the optimal sequence has been decided, then the method has also to be able to accurately predict the final shape.