• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 19
  • 12
  • 4
  • 3
  • 3
  • 1
  • 1
  • 1
  • Tagged with
  • 46
  • 12
  • 9
  • 9
  • 7
  • 7
  • 7
  • 7
  • 7
  • 6
  • 6
  • 6
  • 6
  • 6
  • 6
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Influência dos parâmetros do processo de serramento no corte de capacitores de filme metalizado ultrafino

Mello, Tiago Chaves January 2015 (has links)
Visando determinar os valores ótimos para o processo de serramento de anéis bobinados de filme metalizado ultrafino de alumínio com dielétrico de poliéster a partir das condições atuais do processo de fabricação de capacitores pela empresa Epcos do Brasil, realizou-se a avaliação de diferentes tipos de serras circulares variando-se a velocidade de rotação (n) e o tempo de corte (tc). Desenvolvido projeto de experimento desses três fatores a fim de obter o resultado das interações entre eles quanto à resistência de isolamento (Riso) das peças cortadas. A serra de 160 dentes de metal-duro com revestimento de filme de carbono tipo diamante (DLC) apresentou os melhores resultados quanto à “Riso” acima de 0,378 G e quanto ao número de peças com valor abaixo deste. Constatou-se que “n” não influencia significativamente para a distribuição de “Riso”; porém, gera menos peças abaixo do especificado. Já “tc” não influencia significativamente o processo. Quanto ao tipo de dente, o perfil reto obteve melhor resultado para lâminas de serra com 80 dentes e perfil curvo para lâminas com 160 dentes. Já a espessura da lâmina não influenciou de forma expressiva o processo. A lâmina de aço-rápido apresentou adesão de alumínio na lateral do corpo da serra e, consequentemente, adesão de material na superfície de corte. As lâminas de metal-duro sem revestimento apresentaram falhas no filme metalizado por causa do atrito gerado entre a superfície de corte e a lateral da lâmina; esse inconveniente é eliminado quando ela é revestida com filme DLC apresentando melhorias quanto à “Riso” das peças para “n” menores. Também houve adesão de alumínio na parte inferior do dente devido a uma delaminação da camada de filme DLC. / In order to determine the optimal values for the sawing process of wound rings of metalized ultra-thin film with dielectric of polyester from current conditions of capacitor manufacturing process by Epcos company in Brazil, it was performed the evaluation of different types of circular saws varying the rotational speed (n) and the cutting time (tc). Developed experiment design methodology for these three factors in order to get the result of the interactions between them regarding to the insulation resistance (Riso) of cut parts. Through the analysis of the main effects, the cemented carbide saw with 160 teeth and diamond-like carbon (DLC) film coating showed the best results in terms of "Riso" above 0,378 G and regarding to the number of parts with value below the specified. It was found that "n" does not influence significantly the distribution of "Riso"; however, generates fewer parts below the specified. Now "tc" does not significantly influence the process. Regarding the tooth type, straight profile obtained better results for saw blades with 80 teeth and curved profile for blades with 160 teeth. However the thickness of the blade did not influence significantly the process. The high speed steel blade presented adhesion of aluminum on the side of the saw body and, consequently, adhesion of material on the cutting surface. The cemented carbide blades uncoated presented failures on metalized film because of the friction generated between the cutting surface and the side of the blade; this drawback is eliminated when it is coated with DLC film presenting improvements to the parts "Riso" for lower "n". There was also aluminum adhesion on the bottom of the tooth due to a delamination of the DLC film layer.
22

Nitrificação de efluente de reator anaeróbio compartimentado em filtros percoladores com a utilização da serragem de couro do tipo wet blue como meio suporte / Nitrification of anaerobic baffed reactor effluent into trickling filters using wet blue leather sawing as a filter packing

Aline Costanzo Franchin 29 September 2006 (has links)
Com a utilização de filtros percoladores aeróbios, procurou-se promover a remoção de nitrogênio amoniacal do esgoto sanitário efluente de reator anaeróbio compartimentado, através do processo de nitrificação. O trabalho foi desenvolvido em duas fases; na primeira foi realizada a preparação da serragem de couro utilizando-se peneiramento e lavagens e a seguir iniciou-se a aplicação do esgoto sanitário em quatro filtros percoladores. Os filtros F1 e F2 foram operados com a mesma taxa de aplicação (1,91 'M POT.3'/'M POT.2'.dia) e diferentes meios suportes, sendo brita e serragem de couro do tipo wet blue respectivamente. Os filtros F3 e F4 foram preenchidos com serragem de couro e operaram com taxa de aplicação hidráulica de 4,00 e 6,00 'M POT.3'/'M POT.2'.dia . O filtro F3 apresentou melhores eficiências de remoção para todos os parâmetros, com eficiência média de remoção de NTK, 'N'-'NH IND.3' e DQO de 71%; sendo que a partir do sexagésimo quarto dia, esse filtro passou a apresentar 100% de remoção de NTK e 'N'-'NH IND.3'. Os filtros F1 e F2 podem ter tido problemas com a aeração, já que foram operados com menores taxas de aplicação hidráulica e deveriam apresentar melhores resultados. O filtro F4 apresentou baixas eficiências de remoção, provavelmente devido a maior taxa de aplicação hidráulica. / The aim of the work is to promote the ammoniacal nitrogen removal from anaerobic baffed reactor effluent using aerobic trickling filters, through the nitrification process. The research was developed in two phases; firstly the leather sawing was prepared through sieving and washing, later the domestic sewage was applied into four tricking filters. The F1 and F2 filters were operated with the same hydraulic loading (1,91 'M POT.3'/'M POT.2'.day) and different filter packing. For the F1 filter was used rock and for the F2 wet blue leather sawing. The F3 and F4 filters were filled with leather sawing and operated in a hydraulic loading of 4,00 and 6,00 'M POT.3'/'M POT.2'.day respectively. The F3 filter presented better removal efficiencies for all the parameters, with 70% of average removal efficiency of KTN (Kjeldahl Total Nitrogen), 'NH IND.3'-'N' (ammoniacal nitrogen) and COD (Chemical Oxygen Demand). From the 49th day on, this filter presented 100% of removal efficiency of KTN and 'NH IND.3'-'N'. The F1 and F2 filter were supposed to present better results due to the lower hydraulic loading, but it did not happen, probably because the aeration was not enough. The F4 filter presented low removal efficiency, possibly due to the higher hydraulic loading.
23

Influência das características petrográficas de granitos no processo industrial de desdobramento de blocos / Influence of petrographic characteristics of granites on the industrial process of blocks sawing

Rogério Pinto Ribeiro 19 December 2005 (has links)
O desdobramento de blocos de granitos, em teares multilâminas, é uma das mais complexas operações da indústria da pedra. A qualidade das superfícies das chapas obtidas no processo de serragem (rugosidade) determina o tempo e os insumos gastos nas operações posteriores de polimento, implicando diretamente no custo final. Embora o Brasil seja um dos maiores produtores mundiais de granitos ornamentais (quatro milhões de 'M POT.2'/mês de placas), surpreendentemente, não se têm na literatura científica trabalhos que dão o devido destaque às propriedades intrínsecas dos granitos no processo de serragem. A presente pesquisa tem como objetivo principal correlacionar parâmetros petrográficos com as características físicas e mecânicas de granitos, dando ênfase ao estudo da influência da mineralogia e da anisotropia textural/estrutural, com vistas à melhor orientação desta etapa industrial. Foram escolhidos tipos de granito consagrados comercialmente e acompanhados os desdobramentos de blocos para medidas diretas da rugosidade das superfícies serradas com o auxílio de um equipamento especialmente construído para esta finalidade. Os resultados mostraram que os aspectos texturais (granulação, arranjo, imbricação, grau de microfissuramento) e de alteração dos minerais são os responsáveis pelas diferenças na rugosidade das chapas e na velocidade de processamento / The sawing of granites blocks using multiblade gangsaws is one of the most complex operations in the stone processing industry. The slab surface quality (roughness) obtained after the sawing process determines the time and the inputs required in subsequent polishing operations and thus has a direct implication on the final product cost. Although Brazil is one of the largest world producers of ornamental granites (four million 'M POT.2'/month of slabs), it is surprising to note that there are very little or no scientific literature works available that address major aspects of the intrinsic properties of granites and their role during the sawing process. The present research has the major objective of correlating petrographic parameters with physical and mechanical characteristics of granites with a major emphasis on the role played by mineralogy and textural/structural anisotropy focusing mainly on how to obtain the best orientation during this industrial stage. The samples used are the most widely used granite of high commercial value in Brazil. The sawing process was monitored and subsequent direct measures of the roughness of the sawed surfaces carried out using an equipment specially built for this purpose. The results obtained show that textural (granulation, arrangement, imbrication, degree of microcracking) and alteration aspects of the minerals are responsible for the observed differences in slab roughness and processing speed
24

Adição de resíduo da indústria de granito em escória de aciaria BOF visando sua utilização na produção de cimento. / Utilization of granite waste and BOF steel slag for cement production.

Lúcio Flávio Arrivabene 14 August 2012 (has links)
A produção de aço necessita de etapas e gera resíduo, dentre eles tem-se a escória de aciaria. No estado do Espírito Santo, Brasil, a mineração de granito é uma das principais atividades econômicas gerando o resíduo de serragem de granito. Nesta pesquisa, busca-se o reaproveitamento destes resíduos, de modo a minimizar possíveis problemas ambientais, apontar a viabilidade técnica do seu uso e reciclá-los por meio de utilização na produção de cimento. Alguns dos principais componentes das escórias de aciaria, tais como, o óxido de cálcio, óxido de magnésio e o ferro metálico sofrem transformações químicas em presença de umidade, que provocam expansão volumétrica da escória. Este fenômeno aliado a reatividade da escória tem dificultado sua utilização. Este trabalho é uma contribuição ao estudo do aproveitamento da escória de aciaria, que passa a ser chamada de ss (steel slag) e do resíduo da serragem de granito, que passa a ser chamado gsw (granite sawing waste), oriundo da extração de granito. Os resíduos estão disponíveis em quantidades nos pátios das siderúrgicas e nas áreas de mineração do granito, respectivamente. Para o reaproveitamento foi realizada a caracterização física, química e mineralógica dos resíduos. Diferentes dosagens de misturas foram produzidas com ss e gsw de forma a permitir avaliação das propriedades obtidas nestas misturas visando sua utilização na produção de cimento. Desenvolveu-se misturas nas quais busca-se a basicidade na escória de aciaria, compreendida entre 4 e 5, para valores próximos ao da escória de alto-forno, na faixa de 0,9 a 1,5 cuja utilização na produção de cimento já está normatizada desde 1991 (NBR 5735, ABNT 1991). Misturas com basicidade entre 0,9 a 4 foram pesquisadas e selecionou-se a mistura com basicidade 1,2 para ser utilizada na produção de cimento. Ao longo da pesquisa foi necessária a produção de 3(três) tipos de cimento até se equacionarem os problemas técnicos e operacionais que surgiram ao longo da mesma. Suas propriedades foram medidas e comparadas com as do cimento contendo escória de alto-forno. As análises dos resultados obtidos para o cimento produzido com a mistura são apresentadas e indicam o potencial de utilização dos resíduos como elementos de adição ao cimento apesar da heterogeneidade dos materiais. / Steel making requires production stages and generates waste, such as steel slag. In the State of Espirito Santo, Brazil, granite mining is one of the main economic activities, wich generates granite sawing waste. This study aims at reusing these two types waste in order to minimize possible environmental problems; point out the technical feasibility of their use; and recycle them by using in cement. Some of the main components of steel slag, such as calcium oxide, oxides, and metallic iron undergo chemical transformations in the presence of humidity, wich cause slag volume expansion. This phenomenon, combined with slag reactivity, has made its use difficult. This study is a contribution to the study on reusing steel slag (ss) and granite sawing waste (gsw) deriving from granite mining. These types of waste are available in large amounts in the yards of steelmaking plants and granite mining areas, respectively. In order to reuse waste, physical, chemical and mineralogical characterizations were carried out. Different mix proportions were made with ss and gsw so as to allow the evaluation of the properties obtained from these mix designs, aiming at their use in cement production. The tests sought steel slag basicity between 4 and 5, for values close to those of blast-furnace slag ranging from 0.9 to 1.5, whose use in cement production has been standardized since 1991 ( NBR 5735, ABNT 1991). Mix designes with basicity between 0,9 and 4 were studied, and a mix with basicity 1.2 was chosen to be used in cement production. Throughout the investigation, 3 types of cement needed to be made until all the technical and operational problems arising were solved. Their properties were measured and compared to those of blast-furnace cement. The analyses of the achieved results for the cement made with that mix are presented and they show the potential use of these types of waste as admixture elements to cement, despite material heterogeneity.
25

Estudo do processo e dos parâmetros de corte no serramento da madeira por serra de fita / not available

Alessandro Santini 30 May 2000 (has links)
O presente trabalho apresenta uma revisão bibliográfica sobre o processo de serramento por serra de fita, abordando fatores relativos ao desempenho de corte nas diversas operações deste processo. Na seqüência, apresentam-se os seguintes estudos específicos: características da madeira que exercem influência nas operações de serramento por serra de fita: o processo de serramento e; ferramentas de corte. A fim de se verificar os aspectos teóricos especificados na literatura para adequação do processo de serramento, efetuou-se um estudo de caso em uma serraria, usinando-se a espécie de madeira Pinus oocarpa em operação de desdobro com serra de fita vertical. Neste estudo, realizou-se a medição da potência consumida durante o corte com aquisição de dados em tempo real, a qual possibilitou calcular a potência de corte média. / The present work shows a bibliographical review on band sawing, in respect to the factors related to cutting performance during the several operations of such process. Moreover, the following studies are presented: wood characteristics influencing the band sawing; sawing process itself; and cutting tools. In order to check the theorical aspects encountered in the literature to adequate the sawing process, a case study in a sawmill plant has been carried out. Pinus oocarpa wood species has been machied by unfolding using a vertical bandsaw. The consumed power during the cutting process was measured by a data acquisition system in real time, what allowed the calculation of the average cutting power.
26

Adaptive sawing : - Yield of a concept in reality

Liljengren, Erik January 2009 (has links)
<p>Glue board is the base for much solid wood furniture produced by the IKEA-owned companySwedwood. Glue board is glued together from lamellas which can be produced in different waysbut in all cases is produced from boards coming from a saw-mill. In a saw-mill there aredifferent techniques for producing boards from logs. This thesis is about the Adaptive sawingconcept and its implementation at the Swedwood site in Kostomuksha. The idea with the conceptis to raise the output from the raw material, the yield. This is partly achieved by edging away islittle as possible from the boards in the saw-mill. The boards in the saw-mill are sawn in a waynot unlike through-sawing. When brought to the glue-board factory they are scanned in order tooptimise how to rip out as much lamellas as possible. The ripped lamellas are then cross-cut intodifferent sizes which later are glued to glue board. The objective of this thesis is to examine theyield from log to glue board for the log classes 135-148 mm and 110-120 mm, to try to improveit and to identify problem factors.In order to achieve that it was necessary to be sure of the volume figures at all stages. Theincoming volume was given by the scanner at the log sorting; effort was therefore put down tomake sure the figures could be trusted. For the smaller log class the logs were instead measuredby hand and the volume was calculated. The logs were then sawn in the saw-mill. This was donewith a low production speed and some problems were noted compared with when sawing with astandard technique. The absence of edging was the main reason for these problems. The saw-millline was deemed inappropriate for sawing the smallest log class but could handle the 135 -148mm class and the yield for that class was in line with what could be expected.In the lamella production line some minor problems were noted and the boards from the fourdifferent batches from the 135 – 148 mm log class got different yields mainly due to differencesin wood quality. The yield from log to glue board for these four batches varied from 17.6 % to21.5 % with an average at 19.3 %. The yield was lower than what was achieved for earlieradaptive sawing test batches on other places. Those tests were however done on other diameterclasses and with material that was slightly different than the one in Kostomuksha. Simulationswere done to check how much the yield could be raised if other lamella widths than just thestandard 46 mm lamella width was used. A raise to an average of 20.9 % could then be expectedwhen using the lamella widths 46, 55 and 60 mm.A similar simulation was done for the adaptive material that was produced from the 110 – 120mm log class. The total yield for that material rose from 19.4 % to 22.4 % when using morelamella widths. Lamellas from this material were tested as there was fear, that they would notmeet the standards for glue board production. This did however not prove to be the case. To usethe lamella production for producing such material is however not ideal, since a very smallvolume is produced.</p> / <p>Limfog är basen för de massivträmöbler som görs av IKEA:s helägda leverantör Swedwood.Limfog består av lameller som kan produceras på olika sätt. Oavsett produktionsteknik görs deav brädor som kommer från ett sågverk. På sågverket finns det också sågsätt för att såga utbrädor ur stockar. Det här examensarbetet behandlar konceptet adaptiv sågning och dessimplementering på Swedwoods anläggning i Kostomuksha. Den grundläggande idén medkonceptet är att höja utbytet på råvaran. Detta uppnås bland annat genom att så lite som möjligtkantas bort på brädorna i sågverket. Brädorna sågas upp med vad man kan kalla genomsågning.När brädorna sedan förts till limfogsfabriken scannas de så att så mycket som möjligt ska kunnafås ut av varje bräda i form av lameller. Lamellerna som sågats ut kapas sedan upp i olikastorleksklasser beroende på kvalitet. Dessa limmas sedan ihop till limfog. Syftet med det härexamensarbetet är att ta fram utbytet från stock till färdig limfog för stockklasserna 135 – 148mm och 110 – 120 mm. Dessutom ska problemfaktorer identifieras och utbytet om möjligt höjas.För att uppnå detta syfte var det nödvändigt att ha säkra siffror för alla inblandade volymer isamtliga skeden. Stockarnas volym gav av en mätram vid timmersorteringen. Mycket kraft lasdärför ner för att säkerställa att dessa siffror var trovärdiga. Stockarna i den mindrediameterklassen mättes istället för hand och volym beräknades utifrån mätningarna. Stockarnasågades sedan på sågverket. Produktionshastigheten under sågningarna var låg och en delproblem i jämförelse med när sågning sker på mer traditionellt vis kunde noteras. Avsaknaden avkantning var huvudorsaken till dessa problem. Sågverkslinan visade sig vara olämplig för attsåga den mindre stockklassen, men kunde hantera stockar med en diameter på 135 – 148 mm.Utbytet för dessa var i linje med vad som kunde förväntas.I lamellproduktionslinjen kunde en del smärre produktionsproblem noteras och brädorna från defyra olika omgångarna av 135 – 148 mm stockar fick olika utbyte mest beroende på skillnader iråvarukvalitet. Utbytet från stock till limfog varierade från 17,6 % till 21,5 % och låg i snitt på19,3 %. Detta utbyte var lägra än vad som uppnåtts för adaptiv sågning på andra platser vidtidigare tester. De testerna utfördes dock på andra diameterklasser och det är därför svårt att raktav jämföra siffrorna. Dessutom kan råvaran ha varit något annorlunda. För att se hur mycketutbytet kunde höjas om andra lamellbredder användes förutom bara 46 mm, gjordessimuleringar. Totalutbytet kunde då höjas till i snitt 20,9 % i fall lamellbredderna 46, 55 och 60mm användes.En likadan simulering gjordes på materialet som producerades från diameterklassen 110 – 120mm. Totalutbytet för denna klass steg från 19,4 % till 22,4 % när fler lamellbredder användes.Eftersom det fanns viss oro att lamellerna skulle hålla lägre kvalitet övervakades de ilimfogsproduktionen. Oron visade sig obefogad. Att producera lameller från den diameterklassenär dock inte idealt eftersom den producerade volymen blir så liten.</p>
27

Adaptive sawing : Yield of a concept in reality

Liljengren, Erik January 2009 (has links)
<p>Glue board is the base for much solid wood furniture produced by the IKEA-owned company Swedwood. Glue board is glued together from lamellas which can be produced in different waysbut in all cases is produced from boards coming from a saw-mill. In a saw-mill there aredifferent techniques for producing boards from logs. This thesis is about the Adaptive sawingconcept and its implementation at the Swedwood site in Kostomuksha. The idea with the conceptis to raise the output from the raw material, the yield. This is partly achieved by edging away islittle as possible from the boards in the saw-mill. The boards in the saw-mill are sawn in a waynot unlike through-sawing. When brought to the glue-board factory they are scanned in order tooptimise how to rip out as much lamellas as possible. The ripped lamellas are then cross-cut intodifferent sizes which later are glued to glue board. The objective of this thesis is to examine theyield from log to glue board for the log classes 135-148 mm and 110-120 mm, to try to improveit and to identify problem factors.</p><p>In order to achieve that it was necessary to be sure of the volume figures at all stages. Theincoming volume was given by the scanner at the log sorting; effort was therefore put down tomake sure the figures could be trusted. For the smaller log class the logs were instead measuredby hand and the volume was calculated. The logs were then sawn in the saw-mill. This was donewith a low production speed and some problems were noted compared with when sawing with astandard technique. The absence of edging was the main reason for these problems. The saw-millline was deemed inappropriate for sawing the smallest log class but could handle the 135 -148mm class and the yield for that class was in line with what could be expected.</p><p>In the lamella production line some minor problems were noted and the boards from the fourdifferent batches from the 135 – 148 mm log class got different yields mainly due to differencesin wood quality. The yield from log to glue board for these four batches varied from 17.6 % to21.5 % with an average at 19.3 %. The yield was lower than what was achieved for earlieradaptive sawing test batches on other places. Those tests were however done on other diameterclasses and with material that was slightly different than the one in Kostomuksha. Simulationswere done to check how much the yield could be raised if other lamella widths than just thestandard 46 mm lamella width was used. A raise to an average of 20.9 % could then be expectedwhen using the lamella widths 46, 55 and 60 mm.</p><p>A similar simulation was done for the adaptive material that was produced from the 110 – 120mm log class. The total yield for that material rose from 19.4 % to 22.4 % when using morelamella widths. Lamellas from this material were tested as there was fear, that they would notmeet the standards for glue board production. This did however not prove to be the case. To use the lamella production for producing such material is however not ideal, since a very smallvolume is produced.</p> / <p>Limfog är basen för de massivträmöbler som görs av IKEA:s helägda leverantör Swedwood.Limfog består av lameller som kan produceras på olika sätt. Oavsett produktionsteknik görs de av brädor som kommer från ett sågverk. På sågverket finns det också sågsätt för att såga utbrädor ur stockar. Det här examensarbetet behandlar konceptet adaptiv sågning och dessimplementering på Swedwoods anläggning i Kostomuksha. Den grundläggande idén med konceptet är att höja utbytet på råvaran. Detta uppnås bland annat genom att så lite som möjligtkantas bort på brädorna i sågverket. Brädorna sågas upp med vad man kan kalla genomsågning.När brädorna sedan förts till limfogsfabriken scannas de så att så mycket som möjligt ska kunnafås ut av varje bräda i form av lameller. Lamellerna som sågats ut kapas sedan upp i olikastorleksklasser beroende på kvalitet. Dessa limmas sedan ihop till limfog. Syftet med det härexamensarbetet är att ta fram utbytet från stock till färdig limfog för stockklasserna 135 – 148mm och 110 – 120 mm. Dessutom ska problemfaktorer identifieras och utbytet om möjligt höjas.</p><p>För att uppnå detta syfte var det nödvändigt att ha säkra siffror för alla inblandade volymer isamtliga skeden. Stockarnas volym gav av en mätram vid timmersorteringen. Mycket kraft lasdärför ner för att säkerställa att dessa siffror var trovärdiga. Stockarna i den mindrediameterklassen mättes istället för hand och volym beräknades utifrån mätningarna. Stockarnasågades sedan på sågverket. Produktionshastigheten under sågningarna var låg och en delproblem i jämförelse med när sågning sker på mer traditionellt vis kunde noteras. Avsaknaden avkantning var huvudorsaken till dessa problem. Sågverkslinan visade sig vara olämplig för attsåga den mindre stockklassen, men kunde hantera stockar med en diameter på 135 – 148 mm.Utbytet för dessa var i linje med vad som kunde förväntas.</p><p>I lamellproduktionslinjen kunde en del smärre produktionsproblem noteras och brädorna från defyra olika omgångarna av 135 – 148 mm stockar fick olika utbyte mest beroende på skillnader iråvarukvalitet. Utbytet från stock till limfog varierade från 17,6 % till 21,5 % och låg i snitt på19,3 %. Detta utbyte var lägra än vad som uppnåtts för adaptiv sågning på andra platser vidtidigare tester. De testerna utfördes dock på andra diameterklasser och det är därför svårt att raktav jämföra siffrorna. Dessutom kan råvaran ha varit något annorlunda. För att se hur mycketutbytet kunde höjas om andra lamellbredder användes förutom bara 46 mm, gjordessimuleringar. Totalutbytet kunde då höjas till i snitt 20,9 % i fall lamellbredderna 46, 55 och 60mm användes.</p><p>En likadan simulering gjordes på materialet som producerades från diameterklassen 110 – 120mm. Totalutbytet för denna klass steg från 19,4 % till 22,4 % när fler lamellbredder användes.Eftersom det fanns viss oro att lamellerna skulle hålla lägre kvalitet övervakades de ilimfogsproduktionen. Oron visade sig obefogad. Att producera lameller från den diameterklassenär dock inte idealt eftersom den producerade volymen blir så liten.</p>
28

Adaptive sawing : - Yield of a concept in reality

Liljengren, Erik January 2009 (has links)
Glue board is the base for much solid wood furniture produced by the IKEA-owned companySwedwood. Glue board is glued together from lamellas which can be produced in different waysbut in all cases is produced from boards coming from a saw-mill. In a saw-mill there aredifferent techniques for producing boards from logs. This thesis is about the Adaptive sawingconcept and its implementation at the Swedwood site in Kostomuksha. The idea with the conceptis to raise the output from the raw material, the yield. This is partly achieved by edging away islittle as possible from the boards in the saw-mill. The boards in the saw-mill are sawn in a waynot unlike through-sawing. When brought to the glue-board factory they are scanned in order tooptimise how to rip out as much lamellas as possible. The ripped lamellas are then cross-cut intodifferent sizes which later are glued to glue board. The objective of this thesis is to examine theyield from log to glue board for the log classes 135-148 mm and 110-120 mm, to try to improveit and to identify problem factors.In order to achieve that it was necessary to be sure of the volume figures at all stages. Theincoming volume was given by the scanner at the log sorting; effort was therefore put down tomake sure the figures could be trusted. For the smaller log class the logs were instead measuredby hand and the volume was calculated. The logs were then sawn in the saw-mill. This was donewith a low production speed and some problems were noted compared with when sawing with astandard technique. The absence of edging was the main reason for these problems. The saw-millline was deemed inappropriate for sawing the smallest log class but could handle the 135 -148mm class and the yield for that class was in line with what could be expected.In the lamella production line some minor problems were noted and the boards from the fourdifferent batches from the 135 – 148 mm log class got different yields mainly due to differencesin wood quality. The yield from log to glue board for these four batches varied from 17.6 % to21.5 % with an average at 19.3 %. The yield was lower than what was achieved for earlieradaptive sawing test batches on other places. Those tests were however done on other diameterclasses and with material that was slightly different than the one in Kostomuksha. Simulationswere done to check how much the yield could be raised if other lamella widths than just thestandard 46 mm lamella width was used. A raise to an average of 20.9 % could then be expectedwhen using the lamella widths 46, 55 and 60 mm.A similar simulation was done for the adaptive material that was produced from the 110 – 120mm log class. The total yield for that material rose from 19.4 % to 22.4 % when using morelamella widths. Lamellas from this material were tested as there was fear, that they would notmeet the standards for glue board production. This did however not prove to be the case. To usethe lamella production for producing such material is however not ideal, since a very smallvolume is produced. / Limfog är basen för de massivträmöbler som görs av IKEA:s helägda leverantör Swedwood.Limfog består av lameller som kan produceras på olika sätt. Oavsett produktionsteknik görs deav brädor som kommer från ett sågverk. På sågverket finns det också sågsätt för att såga utbrädor ur stockar. Det här examensarbetet behandlar konceptet adaptiv sågning och dessimplementering på Swedwoods anläggning i Kostomuksha. Den grundläggande idén medkonceptet är att höja utbytet på råvaran. Detta uppnås bland annat genom att så lite som möjligtkantas bort på brädorna i sågverket. Brädorna sågas upp med vad man kan kalla genomsågning.När brädorna sedan förts till limfogsfabriken scannas de så att så mycket som möjligt ska kunnafås ut av varje bräda i form av lameller. Lamellerna som sågats ut kapas sedan upp i olikastorleksklasser beroende på kvalitet. Dessa limmas sedan ihop till limfog. Syftet med det härexamensarbetet är att ta fram utbytet från stock till färdig limfog för stockklasserna 135 – 148mm och 110 – 120 mm. Dessutom ska problemfaktorer identifieras och utbytet om möjligt höjas.För att uppnå detta syfte var det nödvändigt att ha säkra siffror för alla inblandade volymer isamtliga skeden. Stockarnas volym gav av en mätram vid timmersorteringen. Mycket kraft lasdärför ner för att säkerställa att dessa siffror var trovärdiga. Stockarna i den mindrediameterklassen mättes istället för hand och volym beräknades utifrån mätningarna. Stockarnasågades sedan på sågverket. Produktionshastigheten under sågningarna var låg och en delproblem i jämförelse med när sågning sker på mer traditionellt vis kunde noteras. Avsaknaden avkantning var huvudorsaken till dessa problem. Sågverkslinan visade sig vara olämplig för attsåga den mindre stockklassen, men kunde hantera stockar med en diameter på 135 – 148 mm.Utbytet för dessa var i linje med vad som kunde förväntas.I lamellproduktionslinjen kunde en del smärre produktionsproblem noteras och brädorna från defyra olika omgångarna av 135 – 148 mm stockar fick olika utbyte mest beroende på skillnader iråvarukvalitet. Utbytet från stock till limfog varierade från 17,6 % till 21,5 % och låg i snitt på19,3 %. Detta utbyte var lägra än vad som uppnåtts för adaptiv sågning på andra platser vidtidigare tester. De testerna utfördes dock på andra diameterklasser och det är därför svårt att raktav jämföra siffrorna. Dessutom kan råvaran ha varit något annorlunda. För att se hur mycketutbytet kunde höjas om andra lamellbredder användes förutom bara 46 mm, gjordessimuleringar. Totalutbytet kunde då höjas till i snitt 20,9 % i fall lamellbredderna 46, 55 och 60mm användes.En likadan simulering gjordes på materialet som producerades från diameterklassen 110 – 120mm. Totalutbytet för denna klass steg från 19,4 % till 22,4 % när fler lamellbredder användes.Eftersom det fanns viss oro att lamellerna skulle hålla lägre kvalitet övervakades de ilimfogsproduktionen. Oron visade sig obefogad. Att producera lameller från den diameterklassenär dock inte idealt eftersom den producerade volymen blir så liten.
29

Adaptive sawing : Yield of a concept in reality

Liljengren, Erik January 2009 (has links)
Glue board is the base for much solid wood furniture produced by the IKEA-owned company Swedwood. Glue board is glued together from lamellas which can be produced in different waysbut in all cases is produced from boards coming from a saw-mill. In a saw-mill there aredifferent techniques for producing boards from logs. This thesis is about the Adaptive sawingconcept and its implementation at the Swedwood site in Kostomuksha. The idea with the conceptis to raise the output from the raw material, the yield. This is partly achieved by edging away islittle as possible from the boards in the saw-mill. The boards in the saw-mill are sawn in a waynot unlike through-sawing. When brought to the glue-board factory they are scanned in order tooptimise how to rip out as much lamellas as possible. The ripped lamellas are then cross-cut intodifferent sizes which later are glued to glue board. The objective of this thesis is to examine theyield from log to glue board for the log classes 135-148 mm and 110-120 mm, to try to improveit and to identify problem factors. In order to achieve that it was necessary to be sure of the volume figures at all stages. Theincoming volume was given by the scanner at the log sorting; effort was therefore put down tomake sure the figures could be trusted. For the smaller log class the logs were instead measuredby hand and the volume was calculated. The logs were then sawn in the saw-mill. This was donewith a low production speed and some problems were noted compared with when sawing with astandard technique. The absence of edging was the main reason for these problems. The saw-millline was deemed inappropriate for sawing the smallest log class but could handle the 135 -148mm class and the yield for that class was in line with what could be expected. In the lamella production line some minor problems were noted and the boards from the fourdifferent batches from the 135 – 148 mm log class got different yields mainly due to differencesin wood quality. The yield from log to glue board for these four batches varied from 17.6 % to21.5 % with an average at 19.3 %. The yield was lower than what was achieved for earlieradaptive sawing test batches on other places. Those tests were however done on other diameterclasses and with material that was slightly different than the one in Kostomuksha. Simulationswere done to check how much the yield could be raised if other lamella widths than just thestandard 46 mm lamella width was used. A raise to an average of 20.9 % could then be expectedwhen using the lamella widths 46, 55 and 60 mm. A similar simulation was done for the adaptive material that was produced from the 110 – 120mm log class. The total yield for that material rose from 19.4 % to 22.4 % when using morelamella widths. Lamellas from this material were tested as there was fear, that they would notmeet the standards for glue board production. This did however not prove to be the case. To use the lamella production for producing such material is however not ideal, since a very smallvolume is produced. / Limfog är basen för de massivträmöbler som görs av IKEA:s helägda leverantör Swedwood.Limfog består av lameller som kan produceras på olika sätt. Oavsett produktionsteknik görs de av brädor som kommer från ett sågverk. På sågverket finns det också sågsätt för att såga utbrädor ur stockar. Det här examensarbetet behandlar konceptet adaptiv sågning och dessimplementering på Swedwoods anläggning i Kostomuksha. Den grundläggande idén med konceptet är att höja utbytet på råvaran. Detta uppnås bland annat genom att så lite som möjligtkantas bort på brädorna i sågverket. Brädorna sågas upp med vad man kan kalla genomsågning.När brädorna sedan förts till limfogsfabriken scannas de så att så mycket som möjligt ska kunnafås ut av varje bräda i form av lameller. Lamellerna som sågats ut kapas sedan upp i olikastorleksklasser beroende på kvalitet. Dessa limmas sedan ihop till limfog. Syftet med det härexamensarbetet är att ta fram utbytet från stock till färdig limfog för stockklasserna 135 – 148mm och 110 – 120 mm. Dessutom ska problemfaktorer identifieras och utbytet om möjligt höjas. För att uppnå detta syfte var det nödvändigt att ha säkra siffror för alla inblandade volymer isamtliga skeden. Stockarnas volym gav av en mätram vid timmersorteringen. Mycket kraft lasdärför ner för att säkerställa att dessa siffror var trovärdiga. Stockarna i den mindrediameterklassen mättes istället för hand och volym beräknades utifrån mätningarna. Stockarnasågades sedan på sågverket. Produktionshastigheten under sågningarna var låg och en delproblem i jämförelse med när sågning sker på mer traditionellt vis kunde noteras. Avsaknaden avkantning var huvudorsaken till dessa problem. Sågverkslinan visade sig vara olämplig för attsåga den mindre stockklassen, men kunde hantera stockar med en diameter på 135 – 148 mm.Utbytet för dessa var i linje med vad som kunde förväntas. I lamellproduktionslinjen kunde en del smärre produktionsproblem noteras och brädorna från defyra olika omgångarna av 135 – 148 mm stockar fick olika utbyte mest beroende på skillnader iråvarukvalitet. Utbytet från stock till limfog varierade från 17,6 % till 21,5 % och låg i snitt på19,3 %. Detta utbyte var lägra än vad som uppnåtts för adaptiv sågning på andra platser vidtidigare tester. De testerna utfördes dock på andra diameterklasser och det är därför svårt att raktav jämföra siffrorna. Dessutom kan råvaran ha varit något annorlunda. För att se hur mycketutbytet kunde höjas om andra lamellbredder användes förutom bara 46 mm, gjordessimuleringar. Totalutbytet kunde då höjas till i snitt 20,9 % i fall lamellbredderna 46, 55 och 60mm användes. En likadan simulering gjordes på materialet som producerades från diameterklassen 110 – 120mm. Totalutbytet för denna klass steg från 19,4 % till 22,4 % när fler lamellbredder användes.Eftersom det fanns viss oro att lamellerna skulle hålla lägre kvalitet övervakades de ilimfogsproduktionen. Oron visade sig obefogad. Att producera lameller från den diameterklassenär dock inte idealt eftersom den producerade volymen blir så liten.
30

Řezání litých superlitin / On the cutting of cast superalloys

Metelková, Jitka January 2016 (has links)
This work deals with the issue of defects generation during the separation of the castings from a nickel-based superalloy, Inconel 738LC. The technology of investment casting is presented, followed by a description of metallurgy of superalloys, their physical and mechanical properties, as well as their technical applications. The machinability of superalloys and method of castings separation were also described as well as some of the casting defects that were reported to have impact on the generation of the defects after cutting. In the experimental part, the material microstructure and casting defects were analyzed. The experimental machining part consisted first of a comparative study of the friction sawing and plasma arc cutting technology at the standard operating conditions actually used in production. Second, an optimization study for the friction sawing was carried out, with a special focus on the suitability of an alternative cutoff wheel for the chosen application. Application of this wheel allows reducing the security distance between the cut and the part, thus reducing the production cost of the part.

Page generated in 0.0966 seconds