Mould design and manufacturing

In modern manufacturing, coordinate measuring machine is important measuring device for evaluation of products whether they are within the desired accuracy or not. The procedure is collecting sample point (discrete point) from the surface, fitting the cloud point to that best describe geometry surface, convert the constructed surface into dense cloud, align the dense cloud to CAD model and compare for form deviation. In coordinate measuring machine discrete point measurement has a trade-off relation between the sample size and form deviation, increasing sample size results decrease in form deviation but inspection cost increase. So to get the optimal result a good sampling strategy, which minimize the measuring time and achieve the desired accuracy is required. In this work, surface contour curve based adaptive sampling strategy is proposed. The optimal number of slicing plane used for surface contour curve generation is automatically generated from the surface radius of curvature a...

A l’occasion de l’exposition «L’olympisme. Une invention moderne, un héritage antique», Christina Mitsopoulou révélera une partie des coulisses de son travail de recherche en présentant l’œuvre du peintre suisse Émile Gilliéron (1850 – 1924). Cet artiste qui avait dessiné les timbres, affiches, médailles et trophées olympiques, était aussi célèbre pour son impressionnante production de relevés archéologiques des sites antiques grecs auxquels il voua son œuvre. L’étude récente de son fonds d’archives a permis de compléter nos connaissances sur sa formation et son activité artistique.

Avec Christina Mitsopoulou, commissaire de l’exposition, archéologue à l’université de Thessalie, École française d’Athènes.

Vendredi 24 juin, à 17h30, au Centre Vivant-Denon
Gratuit sur réservation par mail à [email protected]

This review paper offers a summary of historical techniques and materials used to produce plaster casts and to treat their surfaces, as found in the historical literature. It reviews a selection of manuals, treatises, and recipe books on the art of the cast makers as well as a selection of patents related to the manufacturing of casts and the coating of their surfaces. The introduction to the review shows how relevant archival, historical, and technical investigation demonstrates that nineteenth century replicas are works of cultural significance in their own right, by means of a synthesis of background information. This paper also offers a brief introduction to plaster moulding and casting as well as a summary of historical recipes on how to treat the surfaces of plaster casts to change the surface properties or their appearance. This review aims therefore to provide a summary of materials used by the nineteenth-century plasterer, and technical information for the use of conservators, researchers, and curators who engage in the care and study of historical plaster casts. Examples from the Victoria and Albert Museum's collection support the information found in the historical literature.

The verification of 3D scanning application for the purpose of dimensional inspection.  The dimensional and geometric deviations of cylindrical shoots of aluminium alloy parts.  Coordinate measuring machine (CMM) and PC DMIS software.  A brief overview of the inspection procedure.

The student industrial work experience scheme (SIWES) was aimed at giving the students opportunity to relate and translate their theoretical knowledge to the real work. This industrial training report presents the experience gathered during my six (6) months of industrial training undertaking at Technology Incubation Centre Birnin Kebbi. I was engaged on the production of foam production and perfume production.

Mould making indushy is a manufacturer and designer for various kinds of mould such as commodity mould, packaging mould and furniture mould for other manufacturing processes. Due to the mould manufacturing process, a workers are exposed to the risks of upper limb disorders such as repetitive tasks, uncomfortable work postures and carry out work for long periods without break. Therefore, the main objective of this study was to identify the prevalence of work-related musculoskclctal disorders among the employee at mould making manufacturing ind"shy. ~rmcrurcd inlerview using Cornell Musculoskclctal Discomfort Questionnaires (CMDQ) were conducted over 35 workes in mould makin-a induslrv in which the age range was from 23 to-38 years (mean 28.54* 4.22 years) while working experience ranges from 1 to l i years (mean 4.31 years 3:09). The results shows that workers in the mould making industry were exposured to ergonomic risk of experiencing discomfort in the upper part of the body s...

A brief overview of each Reverse Engineering step is presented in the paper. Complex freeform model was chosen intentionally in order to determine accuracy level of the whole RE process, using our laboratory equipment. Selected model can be very challenging task regarding to every single step in the REprocess , especially at dimensional verifications process. Accurate and fast results are dependant to good hardware equipment and the newest software exploitation. At dimensional verification of freeform surfaces exists some difficulties how to define deviations between the numerical models. Fact is that no single point from the each model can be used as a marker. Usually, only best fit comparison of two numerical models can be made. We try to demonstrate two different ways to determine deviations between two numerical models (direct and indirect mode). Due to complex surface of the model, some other findings are presented as well.

Sprue has an important role in injection mould. Sprue gives a flow path to travel molten plastic material. As sprue is not a final product so it should be minimized. Sprue design has been modified to save the plastic material. This modified design present the development of sprue design as a gate for two cavities injection mould. Sprue design has been modified to save the plastic material. Part geometry, molding materials, types of runner, runner layout has been considered to design the sprue. Modified sprue design aspects has been discuss in the paper. Uses and benefits of modified sprue with conventional sprue are compared that shows modified sprue has a better efficiency in terms of material saving and conveying the molding material from nozzle to cavity via runner and gate. This modified sprue acts as gate to eliminate the runner. Machining and molding with modified sprue injection mould shows a good quality product with minimum wastage of molding material in terms of feed system produced.

Resumo Com o desenvolvimento de novos materiais para ferramentas de corte, os processos de usinagem de aços endurecidos (com remoção de cavacos em aço com dureza superior a 45 HRC) têm estado cada vez mais em evidência, de tal modo que, em alguns casos, substitui-se o processo de retificação por possibilitar a redução do tempo de produção e do custo de fabricação. Além disso, é possível obter peças com elevado acabamento superficial e tolerâncias apertadas. Este trabalho visa analisar o desgaste de ferramenta de metal duro e possíveis danos causados na superfície da peça através das solicitações térmicas e mecânicas originadas do fresamento com alta velocidade de corte no aço AISI H13 endurecido. A avaliação do desempenho das ferramentas de metal duro consistiu na análise dos seguintes parâmetros: vida, desgaste de ferramenta, dureza, rugosidade e microestrutura. Os resultados obtidos neste estudo mostraram que o material da ferramenta e a velocidade de corte influenciaram no desempenho das variáveis de saída citadas. As ferramentas de metal duro apresentaram baixo rendimento na usinagem HSM (High Speed Machining) e rendimento satisfatório com velocidades de corte convencionais. Palavras-chave: Usinagem com alta velocidade; Aços endurecidos; Rugosidade; Microestrutura; Desgaste de ferramenta.

Recent archaeological excavations revealed a significant amount of bronze casting moulds and cores dated to the Middle-Shang period and demonstrated it as a vital stage in the development of casting technology in Bronze Age China. This study has analyzed fifty-three mould and eight core fragments from the Taijiasi site, dated to the Middle Shang III period, using micro-CT scanning, SEM-EDS, and p-XRD. The results show that four types of materials combined in distinct ways to form three mould types at this site. Moulds for smaller bronze vessels with band-like patterns were constructed with a sand tempered material while only pattern sections were replaced with a c. 5-10 mm layer of fine silt-rich material. In contrast, moulds for larger vessels with extensive decorative patterns have a double-layered structure, comprising a fine silt-rich internal layer and a sand-grog tempered external layer. Moulds for tools and weapons were made of unprocessed loess. Casting cores display a texture similar to sand tempered moulds. This research uncovered a nuanced material selection strategy for mould manufacturing at the site of Taijiasi and highlighted the innovations of mould-making techniques in the Middle Shang period.

This paper presents a design methodology for concrete façade panels that takes into consideration constraints related to digital fabrication machinery. A computational method for the real-time evaluation of industrial mold-making techniques, such as milling and hot wire cutting, was developed. The method rapidly evaluates the feasibility, material use, and machining time of complex geometry molds for architectural façade elements. Calculation speed is achieved by mathematically approximating CAM-machining operations. As results are obtained in nearly real time, the method can be easily incorporated into the architectural design process during its initial stages, when changes to the design are more effective. In the paper, we describe the algorithms of the computational evaluation method. We also show how it can be used to introduce fabrication considerations into the design process by using it to rationalize several types of panels. Additionally, we demonstrate how the method can be used in complex, large-scale architectural projects to save machining time and materials by evaluating and altering the paneling subdivision.

Кандидат технических наук, доцент, * Контактный тел.: (056) 374-83-67 В. Ю. С е л и в е р с т о в Доктор технических наук, профессор *Кафедра литейного производства Национальная металлургическая академия Украины пр. Гагарина, 4, г. Днепропетровск, 49600 Теоретично обгрунтована і застосована технологія, що передбачає використання комбінованої дії на процес формування литої структури алюмінієвих сплавів. Визначені механічні властивості алюмінієвих сплавів отриманих із застосуванням комбінованої технології Ключові слова: алюмінієвий сплав, модифікування, газодинамічна дія Теоретически обоснована и применена технология, предусматривающая использование комбинированного воздействия на процесс формирования литой структуры алюминиевых сплавов. Определены механические свойства алюминиевых сплавов, полученных с применением комбинированной технологии Ключевые слова: алюминиевый сплав, модифицирование, газодинамическое воздействие Theoretically proved and applied the technology which provides using the combined effect on the formation of the cast structure of aluminum alloys. The mechanical properties of aluminum alloys, obtained using the combined technologies are defined.

AISI H13 tool steel has a good combination of mechanical strength and toughness, thus, they are used, as examples, in the manufacture of aluminum extrusion dies, hot forging dies and injection molds of non-ferrous materials and polymers. These tools, in practice, are subjected to tensile and compression stresses during the stages of the heating and cooling processes, which lead to thermal fatigue and also suffer wear. To extend the life span of these tools, new surface treatments are being researched. In the present research work, the influence of the quenching treatment on the surface properties of nitrided AISI H13 steel was studied. First, plasma nitriding was performed at 520ºC with time durations of 12, 24 and 40 hours and gas nitriding at 540ºC with time durations of 42 and 84 hours. Then, nitrided steels were subjected to the treatment of vacuum quenching or in a salt bath quenching from a temperature of 1030ºC applying different soaking times. Vacuum and salt-bath quenching applied on nitrided AISI H13 steel generated an increase in the nitrided layer caused by the additional diffusion of nitrogen towards the core of the specimen, reduction in microhardness along the nitrided layer and a slight increase in core microhardness. In this new nitrided layer, formed after quenching, it was possible to identify, by X-Ray diffraction, a reduction in the intensity of the peaks related to the ε and γ' nitride phases produced after the nitriding, the appearance of new peaks, such as, α' phase (martensite), retained austenite phase, new nitrides, carbides and carbonitrides. It was also verified the influence of nitrogen, present in the new nitrided layer, on the surface hardness, plotting the tempering curve for five different conditions of combined treatment of nitriding followed by quenching. In addition, the microhardness gradient in the cross-section of specimens tempered at 520ºC was analyzed. The presence of nitrogen increased the surface hardness of the steel up to 1.57 HRC compared to conventionally tempered AISI H13 steel. The thermal fatigue test was also carried out on specimens quenched and tempered; quenched, tempered and nitrided; and quenched, tempered, nitrided and quenched. The results indicate that specimens nitride only, had lower surface deformation and higher crack density in the surface and cross-section. The quenched and tempered specimens had the lowest crack propagation rate.

and thermal furnace was combined. The inclusion in the RCC of the annular heat-treatment furnace, as one of the rotary transport-technological conveyor modules, allows heat treatment of the casting to produce bainitic metal structures with high performance characteristics, which gives grounds to call this RСС as foundry-thermal. The described concept of combining casting technology using gasified patterns, using vacuum molds with sand without a binder, knocking out hot castings and, bypassing pearlite transformation for iron-carbon alloys, isothermal hardening (austempering), allows you to use the latest scientific and applied knowledge in the field of structural and special synthesis cast iron and steel with high mechanical properties. The described RСС will ensure an increase in the productivity of production, a reduction in its energy and labor intensity, production space, corresponds to modern high-tech equipment, the design of which is based on the teaching of Acad. L.N. Koshkin, as well as on the scientific and technological developments and patents of the PTIMA NAS of Ukraine.

Reverse engineering is a process of obtaining a geometric computer aided design (CAD) model from three dimensional (3D) point clouddata acquired by scanning/digitising existing parts. There are several reasons for using reverse engineering (RE) technique; absence of the 3D CAD model of the part is one of the key reasons. Companies are investing in RE to reduce the time to create a prototype and to shorten the time to market for a product and to have an edge over their competitors. In the present study, we reverse engineered a specimen component with freeform surfaces via additive manufacturing technique. For this purpose, we used a contact type 3-axis point to point coordinate measuring machine (CMM)to obtain a point cloud data of the component. The CMM works on Geo-met software which can export measured point cloud data in IGES format that a CAD system can read. The CATIA V5 solid modelling software is used to convert point cloud data into 3D CAD model by creating a surface onto th...

Resumo A fabricação de componentes para conformação mecânica possui uma gama de exigências devido aos esforços cíclicos, como por exemplo, fadiga térmica. Devido à capacidade de formar geometrias complexas e usinar metais de alta dureza, a eletroerosão (EDM-Eletrical Discharge Machining) possui eficiência na produção destas matrizes. O estudo da integridade superficial do material erodido torna-se importante para avaliarmos qual são as condições ideais para tratamentos termoquímicos que visam a otimização da superfície da matriz usinada. Neste trabalho, foi investigada a integridade superficial do AISI H13, utilizadas para a fabricação de matrizes de forjamento a quente. Foram avaliadas a rugosidade e camada afetada pela técnica de Perfilometria Mecânica,Microscopia Ótica (MO) e Microscopia Eletrônica de Varredura (MEV). Verificaram-se diferentes superfícies, em diferentes parâmetros de usinagem e profundidades estabelecidas, observandose a subsuperfície do material.

At present, many historical artefacts and furniture are only reconstructed and not restored. They are preserved in terms of material reparation, but their historical value decreases significantly. This work is focused on the comparison of the resistance of high-gloss polyurethane varnish with traditional shellac varnish. The varnishes were applied to oak wood and exposed to interior artificial accelerated ageing in Xenotest. Before and after ageing, cold liquid-resistance tests were performed on the tested specimens and gloss, colour, and adhesion were also evaluated. The structures of the surfaces were also analysed using a confocal laser scanning microscope. As expected, polyurethane varnish was much more durable than shellac varnish. Interestingly, shellac varnish was fairly resistant to water at the beginning, but this resistance was greatly reduced after artificial accelerated ageing. This illustrates the importance of sheltering the shellac treated artefacts in stable temperature-humidity conditions with the least possible effect of solar radiation.

Different painting techniques, materials and application methods that characterise contemporary artworks, with predominantly matt surfaces and uniform tones, make retouching one of the most complicated conservation treatments, since sameness is the main target. The retouching intervention carried out at the Galleria Nazionale d'Arte Moderna e Contemporanea in Rome on Tempi prospettici (1969), an installation by the Italian artist Carlo Alfano, gave the opportunity to investigate a method to obtain different matt/glossy values through the use of natural polymers as binders. The binders chosen (different polysaccharides, cellulose derivatives and isinglass) were analysed, both individually and mixed, through colorimetric and glossmetric measurements. The pigment-binder ratio and the addition of silica to get a modulation of the matt appearance of paint formulations were also evaluated. The comparation of the colorimetric values of painting samples and those of the original paint led to the identification of the best solution for the retouching of the artwork.

Purpose The effect of using microcrystalline cellulose (MCC) as an additive in coating paint films for non-stick coatings was studied in this work. This paper aims to discuss the benefits of MCC blended in the coating paint film that consists of poly(methyl methacrylate) (PMMA) and dammar. Design/methodology/approach PMMA and dammar mixed at a specific Wt.% ratio with xylene as its solvent. Two sets of mixtures were prepared, where one mixture contained MCC and another, without. The mixtures were applied to metal substrates as coating paint films. The performance of the non-stick coating paint film was observed through the adhesive test between adhesion layers on the coating paint film and also through the cross-hatch test for the adhesion of the non-stick coating paint film to the metal substrate. The results correlate with the surface roughness and glossiness tests. Findings The results showed that for the coating paint films, Sample B consisted of 80:20 Wt.% ratio of PMMA-dammar ...

В статье рассматривается коллекция глиняных литейных форм из с. Кобан, переданная в 1882 г. В. И. Долбежевым в Петербург и хранящаяся сейчас в Государственном Эрмитаже. Коллекция включает в себя две парные литейные формы для отливки проушных топоров и заготовок булавок, а также одностворчатую литейную форму для отливки заготовок трапециевидной формы, предположительно тесел. Хотя собрание известно в отечественной литературе,
его новая полная публикация основана на применении современных опыта изучения и методов исследования. На основе проделанного анализа высказано предположение, что собрание
литейных форм может представлять собой единый комплекс — инвентарь погребения литейщика.

In questo lavoro di tesi sono state preparate diverse formulazioni di resine epossidiche da utilizzare in preimpregnati (pre-pregs) per la produzione di compositi rinforzati in fibra di carbonio. Le modifiche della formulazione prese in esame durante il presente lavoro si sono incentrate sulla variazione del sistema indurente utilizzato, modificando l’indurente e/o aggiungendo accelerante al formulato. L’obiettivo di tali modifiche è stato quello di ottenere resine epossidiche che curassero più velocemente e/o che potessero raggiungere temperature di transizione vetrosa maggiori rispetto alla formulazione industriale attualmente utilizzata

Robust interoperability methods are needed in manufacturing systems to implement computer-aided process planning algorithms and to verify their effectiveness. In this paper we discuss applying MTConnect, an open-source standard for data exchange in manufacturing systems, in addressing two specific issues in process planning and verification. We use data from an MTConnect-compliant machine tool to estimate the cycle time required for machining complex parts in that machine. MTConnect data is also used in verifying the conformance of toolpaths to the required part features by comparing the features created by the actual tool positions to the required part features using CAD tools. We demonstrate the capabilities of MTConnect in easily enabling process planning and verification in an industrial environment.

RESUMO A nitretação a plasma é realizada em ferramentas de aços rápidos para aumentar a resistência ao desgaste da aresta de corte e reduzir a tendência do material usinado em aderir na ferramenta. O objetivo do presente trabalho é estudar a viabilidade da nitretação a plasma e do tratamento duplex em brocas de aço rápidoanalisnado o desgaste de brocas de aço rápido M2 submetidas a diferentes parâmetros de nitretação a plasma e deposição de filme de nitreto de titânio (TiN). As brocas passaram primeiro pelo tratamento de nitretação com, variando-se a temperatura em 350°C, 400°C, 450°C, 500oC e 550oC, enquanto o tratamento duplex foi dividido em nitretação convencional a 500 °C seguido de deposição de um filme fino de TiN aplicado pela técnica de deposição a plasma com gaiola catódica à temperatura de 400oC e 500 °C. As brocas nitretadas a 400°C ainda foram submetidas ao processo de deposição de um filme de TiN. Todas as brocas foram caracterizadas por microdureza Vickers e foram ens...

A nitretação consiste de um tratamento de endurecimento superficial, sob a ação de um ambiente nitrogenado, a temperatura e tempo determinados, podendo ser convencional (líquida e gasosa) ou por plasma. Neste trabalho foi utilizado o aço ferramenta AISI H10 modificado, nitretado a plasma com pós-oxidação e em banho de sal, visando à obtenção de uma camada com elevada dureza e resistente à corrosão. A microestrutura da camada nitretada foi caracterizada por microscopia eletrônica de varredura e por difração de raios-X. A profundidade efetiva da camada foi determinada pelo perfil de microdureza e a resistência à corrosão foi avaliada em solução aquosa de 0,5 mol L-1 de cloreto de sódio, por ensaios de polarização potenciodinâmicos, e por ensaios em câmara de névoa salina. A microestrutura obtida após o tratamento térmico prévio de têmpera e revenimento, foi uma matriz constituída de martensita revenida, com a presença de carbonetos esferoidizados, dispersos homogeneamente na matriz. A...

Il mondo dei materiali compositi è in continua espansione, e sono sempre di più le aziende che richiedono componenti prodotti con questi materiali, uno dei quali è la fibra di carbonio. Tali aziende producono inevitabilmente scarti di lavorazione derivanti dal taglio di sagome dai fogli di fibra di carbonio; questi ritagli rappresentano ancora una buona materia prima, che, se ben conservata, può essere utilizzata per la fabbricazione di prodotti secondari. Così facendo sarà possibile ridurre il costo di smaltimento della fibra, e, al contempo, ottenere manufatti in fibra di carbonio a basso costo. È in questo contesto che rientra il lavoro e la ricerca di questo elaborato il cui obbiettivo è riutilizzare gli sfridi di lavorazione per realizzare protesi di piede a basso costo in fibra di carbonio. Un ulteriore attenzione è stata posta al metodo di fabbricazione della protesi, il quale deve risultare semplice da realizzare. Per questa ragione si è deciso che la pressione durante la co...

In this paper a new approach to an automatic controlled system of manufactured parts is suggested. Inputs of the system are: an unordered cloud of 3D points of the part and its CAD model in IGES and STL formats. The 3D cloud is obtained from a high resolution 3D range sensor. After registration between the cloud of points and the STL CAD model, the cloud is segmented by computing the minimal distance and compared to some local geometric properties between the 3D points and the NURBS surfaces. Controlled results are displayed in two ways: visually, using a colour map to display the level of discrepancy between the measured points and the CAD model, and a hardcopy report of the evaluation results of the tolerance specifications. The computing times are 2 seconds for a model STL made up of 15000 triangles put in correspondence with an image made up of 20000 points and about 10 seconds for the same image put in register with the same object represented with its model NURBS.

The master thesis is carried out as a part of the education at the University of Agder and is therefore approved as such. However, this does not imply that the University answers for the methods that are used or the conclusions that are drawn.

Resumo O processo de eletroerosão por penetração permite a usinagem de componentes metálicos nas mais variadas condições de tratamento termo mecânico e durezas. Entretanto, as tabelas e fórmulas tecnológicas empregadas para a execução deste processo não consideram essas distintas condições do material com uma variável. Desta forma, este trabalho objetivou avaliar a influência dimensional na usinagem via eletroerosão por penetração em componentes com e sem tratamento térmico de têmpera seguida de revenimento. Foram avaliadas amostras de aços ferramenta largamente empregados na indústria, representados pelas normas ABNT NM 122 Graus D6 e O1 e ABNT NM 87 Grau 1045. Observou-se uma variação dimensional de 20m entre as amostras. Palavras-chave: Eletroerosão por penetração; Usinagem; Tratamento térmico.

A nitretação tem sido aplicada como um importante processo no incremento da dureza superficial dos aços em geral. O presente trabalho estuda o efeito do processo de nitretação gasosa nas propriedades mecânicas dos aços ferramenta para trabalho a frio AISI D2 e AISI D6. A energia absorvida e os módulos de ruptura desses materiais foram estudados por meio do ensaio de impacto Charpy sem entalhe e ensaio de flexão 4-pontos. Estudos do efeito da nitretação sobre resistência à fadiga e resistência ao desgaste têm sido amplamente abordados nas últimas décadas. A relação entre a nitretação e as propriedades mecânicas, tenacidade e módulo de ruptura dos aços ferramenta tem recebido pouca atenção da literatura.

Selective Laser Melting (SLM) is a versatile fabrication method that provides freedom in design complexity through the development of net or near-net shape metallic components within certain limitations such as dimensional accuracy and surface finish. The rapid development of metallic Additive Manufacturing (AM) technologies and their wide-ranging applications facilitate the unprecedented challenges faced by automotive industries for the production of injection moulding tool inserts in timescales greatly reduced from those experienced when manufacturing using more established and conventional processes. It is accepted that AM has limitations with regard to surface roughness requiring post processing of the parts produced. Global demand is striving for the production of injection moulding tool inserts in terms of higher quality. Previous research was applied to investigate the benefits of AM in the production of low-volume injection moulding tool inserts. Potentially, AM could reduce...

Digitally-driven Fabrication of Fiber-reinforced Composite Panels Composite materials have been explored in architecture for their high performance characteristics that allow customization of functional properties of lightness, strength, stiffness and fracture toughness. Particularly, engineering advancements and better understanding of fiber composites have resulted in growing applications for architectural structures and envelopes. As most new developments in material fabrication start outside the realm of architecture such as in automobile and aeronautical industries, there is need to advance knowledge in architectural design to take advantage of new fabrication technologies. The authors introduce results of new digitally driven fabrication methods for fiber-reinforced composite sandwich panels for complex shaped buildings. This presentation discussed the material properties, manufacturing methods and fabrication techniques needed to develop a proof of concept system using off-the-shelf production technology that ultimately can be packaged into a mobile containerized facility for on-site panel production. The researchers conducted experiments focusing on developing a digitally controlled deformable mold to create composite relief structures for highly customized geometrical façade components. Research findings of production materials, fabrication methods and assembly techniques, are discussed to offer insights into novel opportunities for architectural composite panel fabrication and commercialization.

This paper presents a design methodology for concrete façade panels that takes into consideration constraints related to digital fabrication machinery. A computational method for the real-time evaluation of industrial mold-making techniques, such as milling and hot wire cutting, was developed. The method rapidly evaluates the feasibility, material use, and machining time of complex geometry molds for architectural façade elements. Calculation speed is achieved by mathematically approximating CAM-machining operations. As results are obtained in nearly real time, the method can be easily incorporated into the architectural design process during its initial stages, when changes to the design are more effective. In the paper, we describe the algorithms of the computational evaluation method. We also show how it can be used to introduce fabrication considerations into the design process by using it to rationalize several types of panels. Additionally, we demonstrate how the method can be...

Polyurethanes are versatile materials used widely in many applications. Annual production of polyurethanes is increasing day by day. The most important application of polyurethane covering its major market is polyurethane foam. Different type of foaming systems and foaming processes are used for synthesis of foam. There are two major types of polyurethane foam which are flexible foam and rigid foam. This review has been structured to present an overview of different types of foam, foaming systems, and processes used for production of foam. Also major applications of polyurethanes are presented.

RESUMO Esta pesquisa experimental tem como objetivo analisar a influência dos parâmetros elétricos da usinagem por eletroerosão (EDM – Electrical Discharge Machining) na rugosidade média (Ra) do aço AISI P20, o qual é vastamente utilizado na indústria de moldes para injeção de termoplásticos. Também é proposto neste estudo a otimização destes parâmetros para a obtenção da rugosidade superficial pretendida ao material. O planejamento e os resultados estatísticos foram obtidos através da metodologia de design de experimento (DOE – Design Of Experiments). Utilizou-se do software Statistica para criar gráficos e tabelas de análise baseados na metodologia de superfície de resposta (RSM – Response Surface Methodology). A análise dos resultados mostrou que a duração do pulso de descarga (Ton) e a intensidade da corrente elétrica são os parâmetros de maior efeito para a rugosidade superficial. Baseados em outros trabalhos sobre EDM, a análise estatística apresentou resultados em conformidad...

Este trabalho apresenta o estudo da adesão de revestimentos de TiN-PVD em aço ferramenta para trabalho a quente tipo AISI H13, após pré-tratamento de nitretação sob plasma. A nitretação sob plasma foi conduzida a 520°C, sob diferentes misturas gasosas e tempos. Após a nitretação sob plasma as amostras foram revestidas com TiN. A adesão do TiN foi avaliada pelo método de indentação Daimler-Benz. As cargas críticas de ensaio (L C) foram avaliadas após o trincamento do revestimento (L C1) e após a delaminação (L C2). A adesão do revestimento é dependente das propriedades mecânicas da camada nitretada na região da interface. A adesão aumenta quando a relação H/E e o grau de recuperação elástica da camada nitretada torna-se próximo ao do TiN. Palavras-chave: Nitretação por plasma; Superfícies; Revestimento; Adesão.

As the UN Agenda 2030 recognizes heritage protection in several goals, this research was focused on the improvement of the graffiti removal from stones. The cleaning of two graffiti paints with different composition (an alkyd- and an acrylic–based paints) from two stones (gneiss and travertine) was performed considering a synergistic approach based on the combination of a low-toxic solvent ternary mixture, followed by an Nd:YAG laser. The different concentrations of the low-toxic solvents were based on the triangular Teas graph, keeping similar Hansen solubility of the products commonly used in conservation of cultural heritage: methyl ethyl ketone (MEK) and n-butyl acetate. The n-butyl acetate was replaced by mixture A (51% ethyl alcohol/11% acetone/38% isooctane) and MEK by mixture B (7%/13%/80%). Regardless of the graffiti composition, the gneiss was satisfactorily cleaned with the mixture A, while for the travertine, the best results were achieved by the mixture B. Then, surface...

Precision of materialized designs is the conventional goal of digital fabrication in architecture. Recently, however, an alternative concept has emerged which refashions the imprecisions of digital processes into creative opportunities. While the computational design community has embraced this idea, its novelty results in a yet incomplete understanding. Prompted by the challenge of the still missing knowledge, this study explored imprecision in four digital fabrication approaches to establish how it influences the aesthetic attributes of materialized designs. Imprecision occurrences for four different digitally aided materialization processes were characterized. The aesthetic features emerging from these imprecisions were also identified and the possibilities of tampering with them for design exploration purposes were discussed. By considering the aesthetic potentials of deliberate imprecision, the study has sought to challenge the canon of high fidelity in contemporary computation...

As the UN Agenda 2030 recognizes heritage protection in several goals, this research was focused on the improvement of the graffiti removal from stones. The cleaning of two graffiti paints with different composition (an alkyd- and an acrylic–based paints) from two stones (gneiss and travertine) was performed considering a synergistic approach based on the combination of a low-toxic solvent ternary mixture, followed by an Nd:YAG laser. The different concentrations of the low-toxic solvents were based on the triangular Teas graph, keeping similar Hansen solubility of the products commonly used in conservation of cultural heritage: methyl ethyl ketone (MEK) and n-butyl acetate. The n-butyl acetate was replaced by mixture A (51% ethyl alcohol/11% acetone/38% isooctane) and MEK by mixture B (7%/13%/80%). Regardless of the graffiti composition, the gneiss was satisfactorily cleaned with the mixture A, while for the travertine, the best results were achieved by the mixture B. Then, surface...

Adhesives that use water as a dispersion medium are divided into water-soluble adhesives, water-dispersible adhesives and water-emulsion adhesives. According to the source of raw materials, water-based adhesives are mainly divided into water-based polyurethane adhesives, water-based polyacrylate adhesives, water-based epoxy adhesives, water-based silicone adhesives, polyvinyl acetate emulsion adhesives, Neoprene, etc. Pros and Cons Water-based adhesives are one of the development trends of adhesives. Compared with solvent-based adhesives, water-based adhesives have the advantages of no solvent release, environmental requirements, low cost, non-flammability, and safe use. The solid content is relatively high, up to 50% to 60%. However, due to the slow volatilization of water, the curing of the glue is slowed down or heating and drying equipment is required. Development History Water-based (sex) adhesive is one of the oldest varieties. In ancient times, people used water-soluble polymers containing natural substances such as bone glue and casein as adhesives. Water-based rubber-to-metal adhesives are among the most widely used, and their first breakthrough began in 1981 with the successful development of Chemosil XW 3447. It outperforms all solvent-based products in adhesion and brake fluid resistance. However, it is not as good as solvent-based products in terms of adhesion to natural rubber. Cons: 1. The performance is limited, the heat resistance is not enough, the bonding strength is not high, and the chemical resistance is poor; 2. It needs to be equipped with special hot-melt equipment for construction, such as hot-melt glue machine and hot-melt glue gun; 3. The bonding will be affected by the weather and season. Development History In 1965, after the American Shell Chemical Company commercialized SBS and SIS, it began to be used in the manufacture of hot-melt pressure-sensitive adhesives, and SIS was used as the preferred raw material for hot-melt pressure-sensitive adhesives. greater than 100MPa. 7. Most of the inorganic glue is a kind of paste mixed with solid and liquid. The raw materials are readily available, inexpensive and easy to use. Development History According to research, in the large-scale painted bronze chariots and horses of the Qin Dynasty unearthed from the Qin Terracotta Warriors and Horses Museum, inorganic adhesive was used at the connection of silver pieces, and its composition was basically the same as that of modern phosphate adhesives.

Adhesives that use water as a dispersion medium are divided into water-soluble adhesives, water-dispersible adhesives and water-emulsion adhesives. According to the source of raw materials, water-based adhesives are mainly divided into water-based polyurethane adhesives, water-based polyacrylate adhesives, water-based epoxy adhesives, water-based silicone adhesives, polyvinyl acetate emulsion adhesives, Neoprene, etc. Pros and Cons Water-based adhesives are one of the development trends of adhesives. Compared with solvent-based adhesives, water-based adhesives have the advantages of no solvent release, environmental requirements, low cost, non-flammability, and safe use. The solid content is relatively high, up to 50% to 60%. However, due to the slow volatilization of water, the curing of the glue is slowed down or heating and drying equipment is required. Development History Water-based (sex) adhesive is one of the oldest varieties. In ancient times, people used water-soluble polymers containing natural substances such as bone glue and casein as adhesives. Water-based rubber-to-metal adhesives are among the most widely used, and their first breakthrough began in 1981 with the successful development of Chemosil XW 3447. It outperforms all solvent-based products in adhesion and brake fluid resistance. However, it is not as good as solvent-based products in terms of adhesion to natural rubber. Cons: 1. The performance is limited, the heat resistance is not enough, the bonding strength is not high, and the chemical resistance is poor; 2. It needs to be equipped with special hot-melt equipment for construction, such as hot-melt glue machine and hot-melt glue gun; 3. The bonding will be affected by the weather and season. Development History In 1965, after the American Shell Chemical Company commercialized SBS and SIS, it began to be used in the manufacture of hot-melt pressure-sensitive adhesives, and SIS was used as the preferred raw material for hot-melt pressure-sensitive adhesives. greater than 100MPa. 7. Most of the inorganic glue is a kind of paste mixed with solid and liquid. The raw materials are readily available, inexpensive and easy to use. Development History According to research, in the large-scale painted bronze chariots and horses of the Qin Dynasty unearthed from the Qin Terracotta Warriors and Horses Museum, inorganic adhesive was used at the connection of silver pieces, and its composition was basically the same as that of modern phosphate adhesives.

Concurrent engineering is an important philosophy in achieving better time to market in new product development. While the use of design teams is achieving some success there is a need for modern software tools which support the design process to be radically improved. This paper provides a contribution in the area of decision support systems based on the use of product and manufacturing models to provide appropriate information. Typically design for manufacture systems provide only support for one process e.g. design for assembly, design for machining. However, when the full breadth of design for manufacture is considered there are many aspects which must be addressed. This leads to the need for information systems to be able to support multiple views of a product, where each view provides the appropriate representation to support one manufacturing perspective. This paper discusses the requirements of a reasoning system which is able to provide multiple views of a product and which...

In this study, rubber seed/shea butter oil was used to formulate core oil. The formulated core oil was characterised. D-optimal mixture design was used for multi response optimisation of the functional properties of rubber seed-shea butter coil oil. Desirable values for some responses might be obtained from a factor combination while for others responses not so desirable values. Through multiple response optimisations, a factor setting that gives the desirable values for all responses was obtained. The selected optimum mixture setting for the formulated core oil is 65.937% Rubber seed and 34.063% Shea butter oil at desirability of 0.924. Under the optimum condition the functional properties of the core oil was found to be 39.57KN/M2, 626.85KN/M2, 36.63KN/M2, 593.906KN/M2, 412.605 and 167.309s for Green Compressive Strength, Dry Compressive Strength, Green Tensile Strength, Dry Tensile Strength, Permeability and Collapsibility respectively. The optimum conditions were validated with ...

The Failure Mode and Effect Analysis (FMEA) employing the Risk Priority Numbers (RPN) have been used extensively for identifying and prioritizing failure modes with a view of mitigating their impact on equipment failure. However, in its traditional form, the prioritization approach through the RPN lacks the objectivity required for robust risk assessment, more so, where maintenance data is available, which could enhance such objectivity. This paper extends a quantitative approach for prioritizing failure modes and component failures in facilities, and more specifically, leverages on maintenance data often recorded in such facilities. To enhance the objectivity of the risk prioritization process, the proposed approach integrates three objective measuresthe cost of failure, failure occurrence rate and percentage downtime effects of equipment failure. The integrated measures are demonstrated as more robust for prioritizing risks as opposed to ordinal indices as the case in the conventional FMEA approach. Using historical maintenance records, a three-step ranking approach is proposed for prioritizing critical failure modes in a thermal power plant where a case study is discussed. Moreover, the study compares the results derived from the prioritization approach with that derived utilizing the conventional RPN method. The comparative study demonstrates the added value of a more objective and quantitative prioritization approach for maintenance decision support. Ultimately, the critical failure modes are evaluated using a decision scheme to allocate appropriate maintenance strategies as the final step of risk assessment (i.e. risk treatment). The proposed approach is viewed as generalizable, intuitive and offering insights to the maintenance practitioners.

This paper reports the successful characterisation of polymersfrom past conservation treatments using Raman spectroscopywith a fibre-optic probe. It has been demonstratedfor the first time that this methodology is well suited to thein-situ examination of polymers used as adhesives and gapfillersfor conservation of glass artefacts. By means of aRaman spectroscopic instrument with a fibre-optic probe,conservation polymer spectra were recorded non-destructively,with a spectral resolution of 2 cm-1 in the range 200-3200 cm-1. Polymer identification proved straightforward forgap-fillers and, for adhesives, different polymers were alsosuccessfully distinguished, even in a glass / adhesive /glass bond less than 100 μm in width. In addition to polymeridentification, Fe2O3 was identified as the pigment not onlyin restored areas but also in the original grisaille paint forthe grey toning for the glass pictorial scene.

Com o desenvolvimento de novos materiais para ferramentas de corte, os processos de usinagem de aços endurecidos (com remoção de cavacos em aço com dureza superior a 45 HRC) têm estado cada vez mais em evidência, de tal modo que, em alguns casos, substitui-se o processo de retificação por possibilitar a redução do tempo de produção e do custo de fabricação. Além disso, é possível obter peças com elevado acabamento superficial e tolerâncias apertadas. Este trabalho visa analisar o desgaste de ferramenta de metal duro e possíveis danos causados na superfície da peça através das solicitações térmicas e mecânicas originadas do fresamento com alta velocidade de corte no aço AISI H13 endurecido. A avaliação do desempenho das ferramentas de metal duro consistiu na análise dos seguintes parâmetros: vida, desgaste de ferramenta, dureza, rugosidade e microestrutura. Os resultados obtidos neste estudo mostraram que o material da ferramenta e a velocidade de corte influenciaram no desempenho das variáveis de saída citadas. As ferramentas de metal duro apresentaram baixo rendimento na usinagem HSM (High Speed Machining) e rendimento satisfatório com velocidades de corte convencionais.