the last few years the sawmilling industry has faced the economic pressure of increasing raw material costs, increasing conversion costs and limited product value due to competition from other products, one result of this pressure has been the development of process control systems which automate many of the cutting decisions required to convert tree-length logs into marketable products. Regardless of whether saws are positioned automatically or manually, a set of cutting instructions is essential. These instructions should, for the available log supply, provide the most economical yield consistent with market demands and mill constraints. Two critical decisions are made in converting logs into lumber. The bucking decision constrains the lumber length and hence may limit the value of the lumber. The sawing decision determines the lumber products which can be sawn from the resulting short logs. The two decisions cannot be analyzed in isolation. In order to determine the bucking strategy which yields the mix of short logs which will produce the maximum lumber value it is necessary to know the sawing pattern which will be used to convert the logs into lumber. Similarly, given a limited log supply of fixed characteristics, limited sawmill capacity and restrictions on market demand for lumber products, the optimum sawing strategy cannot be determined without information on the population of short logs which will develop from the bucking decision. Formulating the problem of determing optimum bucking-saving decisions for a limited log supply and limited sawmill capacity as a linear programming model is attractive but the large number of alternative cutting decisions make such a formulation intractable. The problem of deterring optimal bucking and saving strategies for a single log can be modelled as a dynamic programming recursion. However, the dynamic programming approach cannot efficiently handle the large number of constraints inherent in formulating an optimum bucking-sawing strateqy for a given population of tree-length logs. It was shown that the linear and dynamic programming models could be combined using Dantzig-wolfe decomposition. The linear model determines the combination of cutting strategies which optimize an objective function subject to constraints. The dynamic programming model supplies the linear model with new activities as required. The decomposition approach is attractive because it avoids the necessity of working with all possible activities in the linear programme. The L.P. calculates with the basis inverse and the dynamic programming sub-problem generates new bucking-sawing activities as required by the L. P. The efficiency of the technique was demonstrated by determing optimal bucking and sawing strategies for a population of 967 long logs. / Forestry, Faculty of / Graduate

Thesis (doctoral)--Helsinki University of Technology, 2004. / Includes bibliographical references. Also available on the World Wide Web.

Orientador: Marcos Tadeu Tibúrcio Gonçalves / Banca: Manoel Cleber de Sampaio Alves / Banca: Ivaldo de Domenico Valarelli / Resumo: O presente trabalho apresenta uma análise de parâmetros para a seleção de material de ferramenta de corte indicando o uso do Stellite como alternativa para obter melhor produtividade nas serrarias de desdobro de madeiras no Brasil. Para tanto, estudou-se as inter relações entre a propriedades físico químicas de espécies de madeira tropical e o processamento mecânico de desdobro das mesmas, além das origens do desgaste dos materiais empregados como ferramenta de corte. Foram realizados experimentos para determinar as características de densidade básica, teor de sílica e acidez de algumas espécies de madeira tropicais. As espécies estudadas foram: Angelim vermelho (Dinizia excelsa Ducke), Angelim pedra (Hymenolobium petraeum Ducke), Maçaranduba (Manilkara huberi (Ducke) Chevalier), Itaúba (Mezilourus lindaviana Schwacke & Mez), Mandioqueira lisa (Qualea albifloraWarm), Mandioqueira escamosa (Qualea paraensis Ducke) e Quaruba fissurada (Vochysia maxima Ducke). Para tais experimentos, as amostras foram colhidas e gerenciadas nas regras do manejo sustentável. Após a caracterização das espécies e análise do grau de abrasividade das mesmas, foi escolhida a espécie "Maçaanduba" para os testes de desempenho em processos de usinagem e, nas condições de corte e processamento utilizadas, relata-se de forma comparativa os apectos teóricos citados na revisão bibliográfica. Como resultado, pode-se comprovar que o material Stellite apresentou desempenho superior relativo ao desgaste e avarias, quando comparado com outros materiais como o metal duro, além de demonstrar um efetivo ganho de produtividade no serramento de toras de madeira de maçaranduba / Abstract: This study presents an analysis of selection parameters for cutting tool materials, indicating Stellite alloy as a substitute to improve sawmill productivity in Brazil. For that purpose, it was studied the interrelationship between the physical and chemical properties of tropical wood and the wood cutting mechanical process, as well as the origins of wear in cutting tool materials. Some tropical woods were tested for specific, gravity, silica content and acidity. The following species were studied: Angeli vermelho (Dinizia excelsa Ducke), Angelim pedra (Hymenobolobium petraeum Ducke), Maçaranduba (Manilkara huberi (Ducke) Chevalier), Itaúba (Mezilaurus lindaviana Schwacke & Mez), Mandioqueira lisa (Qualea albiflora Warm), Mandioqueira escamosa (Qualea paraensis Ducke) e Quaruba fissurada (Vochysia maxima Ducke). For those experiments, the samples were collected and processed following sustainable management practices. After characterization and analysis of abrasion degree of those species, the Manilkara huberi (Ducke) Chevalier was selcted for the machining process performance tests. Under the cutting and processing conditions established, the theoretical aspects cited in the references are comparatively reported. As a result, it was possible to demonstrate that the Stellite alloy displayed better wear and tear perfomance when compared with other materials sucha as hard beside demonstrating effective productivity gain when sawing Manilkara huberi (Maçaranduba) wood / Mestre

No description available.

Thesis (Ph. D.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 90-94). Also available on the World Wide Web.

Made available in DSpace on 2014-06-11T19:27:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-08-08Bitstream added on 2014-06-13T20:47:45Z : No. of bitstreams: 1 gehringjunior_w_me_guara.pdf: 18287004 bytes, checksum: 736e773d746f989051987a24251619b8 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O presente trabalho apresenta uma análise de parâmetros para a seleção de material de ferramenta de corte indicando o uso do Stellite como alternativa para obter melhor produtividade nas serrarias de desdobro de madeiras no Brasil. Para tanto, estudou-se as inter relações entre a propriedades físico químicas de espécies de madeira tropical e o processamento mecânico de desdobro das mesmas, além das origens do desgaste dos materiais empregados como ferramenta de corte. Foram realizados experimentos para determinar as características de densidade básica, teor de sílica e acidez de algumas espécies de madeira tropicais. As espécies estudadas foram: Angelim vermelho (Dinizia excelsa Ducke), Angelim pedra (Hymenolobium petraeum Ducke), Maçaranduba (Manilkara huberi (Ducke) Chevalier), Itaúba (Mezilourus lindaviana Schwacke & Mez), Mandioqueira lisa (Qualea albifloraWarm), Mandioqueira escamosa (Qualea paraensis Ducke) e Quaruba fissurada (Vochysia maxima Ducke). Para tais experimentos, as amostras foram colhidas e gerenciadas nas regras do manejo sustentável. Após a caracterização das espécies e análise do grau de abrasividade das mesmas, foi escolhida a espécie Maçaanduba para os testes de desempenho em processos de usinagem e, nas condições de corte e processamento utilizadas, relata-se de forma comparativa os apectos teóricos citados na revisão bibliográfica. Como resultado, pode-se comprovar que o material Stellite apresentou desempenho superior relativo ao desgaste e avarias, quando comparado com outros materiais como o metal duro, além de demonstrar um efetivo ganho de produtividade no serramento de toras de madeira de maçaranduba / This study presents an analysis of selection parameters for cutting tool materials, indicating Stellite alloy as a substitute to improve sawmill productivity in Brazil. For that purpose, it was studied the interrelationship between the physical and chemical properties of tropical wood and the wood cutting mechanical process, as well as the origins of wear in cutting tool materials. Some tropical woods were tested for specific, gravity, silica content and acidity. The following species were studied: Angeli vermelho (Dinizia excelsa Ducke), Angelim pedra (Hymenobolobium petraeum Ducke), Maçaranduba (Manilkara huberi (Ducke) Chevalier), Itaúba (Mezilaurus lindaviana Schwacke & Mez), Mandioqueira lisa (Qualea albiflora Warm), Mandioqueira escamosa (Qualea paraensis Ducke) e Quaruba fissurada (Vochysia maxima Ducke). For those experiments, the samples were collected and processed following sustainable management practices. After characterization and analysis of abrasion degree of those species, the Manilkara huberi (Ducke) Chevalier was selcted for the machining process performance tests. Under the cutting and processing conditions established, the theoretical aspects cited in the references are comparatively reported. As a result, it was possible to demonstrate that the Stellite alloy displayed better wear and tear perfomance when compared with other materials sucha as hard beside demonstrating effective productivity gain when sawing Manilkara huberi (Maçaranduba) wood

Redwood (Sequoia sempervirens (D. Don) Endl.) has been identified as a species with considerable potential for plantation forestry in New Zealand. Investment decisions in high value alternate species must be based on accurate wood quality and value predictions. There is an opportunity to extend non-destructive evaluation tools available to redwood growers, and to present the outputs of the growth model by log products and sawn timber. A redwood pruned buttlog sawing simulator has been developed however the simulator had not been tested with real data. Twelve redwood trees from Mangatu estate were selected for a sawing study; these logs were reconstructed and run through the sawing simulator. Computerised log processing was used to produce simulated pruned log sawing outturn from the redwood Buttlog Sawing Simulator, and results were compared to real results from a sawing study. The objective of the study was therefore to determine how well the simulator matched volume and grade out-turn from twelve logs. This study found the many inconsistencies between simulated data and real data; particularly related to log size. While this study was unsuccessful in validation of the redwood sawing simulator, it provides initial insight into the simulators strengths and short comings.

Vid väggsågning i betong uppkommer det mycket damm. Detta damm tas till viss del upp av det vatten som appliceras för att kyla klingan under sågning, vilket leder till en så kallad slurry. Slurryn samt dammet behöver efter avklarad sågning tas upp vilket resulterar i extra arbetsmoment för brukaren av sågen. Det största problemet här är dock det damm som inandas vilket kan leda till sjukdomar såsom silikos. Dessa sjukdomar kommer i framtiden antagligen leda till nya lagkrav kring hur dammet behöver tas hand om innan brukaren kan andas in det. Syftet med studien har därmed varit att utreda hur damm och slurry kan tas upp vid väggsågning. Problemet med väggsågning gentemot andra former av bearbetning i betong har varit svårigheten att täta av gentemot ytan som bearbetning sker i. I fallen med borrning är det tillexempel möjligt att sluta av området och skapa undertryck som då suger upp damm och slurry. För att ge en grund till konceptframtagning utfördes en observation av väggsågning för att skapa förståelse för hur dammet och slurryn beter sig under sågning. Vidare utfördes även en fallstudie för att samla data gällande hur problemet löses idag samt samla punkter från industrin gällande vilka egenskaper lösningen bör ha för att anses som attraktiv i håltagningsindustrin. Utifrån den insamlade empirin genererades koncept med hjälp av brainstorming samt morfologi. Dessa utvärderades sedan med Husqvarna samt med hjälp av Pughs matris där kriterierna för sållningen togs utifrån fallstudiens resultat. Resultatet här blev en pådragsenhet som fäster i klingskyddets befintliga geometrier och tar upp damm och slurry vid den punkt i klingskyddet där den största delen av damm och slurry koncentreras vid sågning. Efter sållningen togs en prototyp fram för att kunna verifiera att damm och slurry kunde tas upp samt för att mäta dess effektivitet. Resultatet av prototyptestet var att konceptet kunde ta upp cirka 23% av slurryn samt markant reducera det synliga dammet. Konceptet kunde därmed anses uppfylla studiens syfte, speciellt gällande dammet då dess skadliga effekter på så sätt kan reduceras. / Wall sawing in concrete generates a lot of dust. The dust is partly collected by the water that is applied as a coolant for the blade, which leads to a mixture called ”slurry”. The slurry as well as the dust needs to be removed after the sawing has been completed, which adds extra steps to the process for the user of the saw. The biggest issue here is the dust that is inhaled by the user, which can lead to diseases such as silicosis . This will probably lead to new regulations regarding how dust is managed, which has been the background of this thesis. The purpose of this study is therefore to evaluate how dust and slurry can be collected during wall sawing. The problem in wall sawing compared to other forms of processing of concrete is the difficulty in creating a seal towards the surface where the processing is being executed. It is for instance easier to create a sealed space around the are of processing during drilling where you can create a vacuum to collect the dust and slurry. An observation was conducted in order to give a basis for how the dust and slurry is acting during sawing. A case study was also executed to gather data regarding how the problem is solved today in the industry as well as to provide intel regarding important attributes that  concepts must have in order to be considered attractive to the industry. Concepts were generated with the collected data as a base through brainstorming and morphology. The concepts were evaluated together with Husqvarna as well as with pugh’s matrix, where the set of criterias had been collected from the case study. The result was a slide on unit that locks to existing geometries and collects dust and slurry at the point where the biggest concentration is achieved during sawing. After the evaluation, a prototype was constructed in order to verify that dust and slurry could be collected and to measure the efficiency of the concept. The result of the test was that the prototype could collect approximately 23% of the slurry as well as significantly reduce the amount of visible dust. The concept could thereby fulfil the purpose of the study, especially regarding the decreasion of dust since the harmful effects of inhalation could be reduced.

A etapa de serragem de blocos (desdobramento) de granitos ornamentais considerando uma visão integrada entre as propriedades das rochas e o desempenho de máquinas, equipamentos e insumos, pode contribuir de forma fundamental para o aprimoramento do setor de rochas ornamentais. Mesmo com crescimentos marcantes na produção e exportação e grande avanço tecnológico, o empirismo predomina no processo produtivo aumentando a possibilidade de desperdícios, quebra de equipamentos, defeitos nas chapas, etc. Para minimizar a utilização da prática e otimizar o processo produtivo, este trabalho objetiva a correlação entre parâmetros operacionais e características tecnológicas das rochas para melhorar a qualidade das chapas produzidas. Foram acompanhadas as serragens e coletadas amostras de três materiais de grande demanda e efetuadas análises petrográficas, determinações da rugosidade e tratamentos estatísticos que, conjuntamente, com dados operacionais provenientes das serragens, avaliou-se a qualidade das superfícies serradas. Este estudo comprova a lacuna existente entre os estudos relacionados às variáveis envolvidas no processo de corte e as características petrográficas e da necessidade de uma pesquisa aplicada que permita a definição de procedimentos adequados na etapa de beneficiamento primário de granitos ornamentais, com a participação intensa das empresas que atuam nesse ramo da economia. / The industry of ornamental and dimension stone can be improved by the global and integrated overview of stone properties and performance machines, equipment and insums. Although with excellent growth in production and exportation and great technological advance, the empirism predominates in the productive process, a practice that might leads to loses, failures of equipment, defects in final product and other problems. Pointing this question are presented and correlated operational parameters of the sawing processes and technological properties of rocks, intending to contribute with the optimization of the productive processes and improve quality of slabs. Three varieties of granites were selected, sampled and subjected to petrographical analysis and rugosity evaluation. For each rock the block cut processes using gang saws was accompanied. The set of laboratorial and processes data was treated statistically and analyzed expecting to evaluate the quality of sawed surface slabs. The results obtained are not conclusive and pointing the necessity of future studies to understanding the effective relations between the petrographical features and processes procedures during block cut step in the dimension stone industry. Is expected this approach resulting in better guides to improve the quality of slabs and minimize loses during the processes.

A etapa de serragem de blocos (desdobramento) de granitos ornamentais considerando uma visão integrada entre as propriedades das rochas e o desempenho de máquinas, equipamentos e insumos, pode contribuir de forma fundamental para o aprimoramento do setor de rochas ornamentais. Mesmo com crescimentos marcantes na produção e exportação e grande avanço tecnológico, o empirismo predomina no processo produtivo aumentando a possibilidade de desperdícios, quebra de equipamentos, defeitos nas chapas, etc. Para minimizar a utilização da prática e otimizar o processo produtivo, este trabalho objetiva a correlação entre parâmetros operacionais e características tecnológicas das rochas para melhorar a qualidade das chapas produzidas. Foram acompanhadas as serragens e coletadas amostras de três materiais de grande demanda e efetuadas análises petrográficas, determinações da rugosidade e tratamentos estatísticos que, conjuntamente, com dados operacionais provenientes das serragens, avaliou-se a qualidade das superfícies serradas. Este estudo comprova a lacuna existente entre os estudos relacionados às variáveis envolvidas no processo de corte e as características petrográficas e da necessidade de uma pesquisa aplicada que permita a definição de procedimentos adequados na etapa de beneficiamento primário de granitos ornamentais, com a participação intensa das empresas que atuam nesse ramo da economia. / The industry of ornamental and dimension stone can be improved by the global and integrated overview of stone properties and performance machines, equipment and insums. Although with excellent growth in production and exportation and great technological advance, the empirism predominates in the productive process, a practice that might leads to loses, failures of equipment, defects in final product and other problems. Pointing this question are presented and correlated operational parameters of the sawing processes and technological properties of rocks, intending to contribute with the optimization of the productive processes and improve quality of slabs. Three varieties of granites were selected, sampled and subjected to petrographical analysis and rugosity evaluation. For each rock the block cut processes using gang saws was accompanied. The set of laboratorial and processes data was treated statistically and analyzed expecting to evaluate the quality of sawed surface slabs. The results obtained are not conclusive and pointing the necessity of future studies to understanding the effective relations between the petrographical features and processes procedures during block cut step in the dimension stone industry. Is expected this approach resulting in better guides to improve the quality of slabs and minimize loses during the processes.