161 resultados para CUTTING STOCK PROBLEM

em Doria (National Library of Finland DSpace Services) - National Library of Finland, Finland


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Tämän tutkimuksen tavoitteena oli selvittää, pitäisikö trimmihävikin kustannukset lisätä case yrityksen asiakaskannattavuuslaskelmaan. Trimmihävikin vaihtelua asiakkaiden välillä tutkittiin yhdellä case yrityksen tuotantolinjalla. Myös tilaustekijöiden sekä ajankohdan vaikutusta trimmihävikin määrään selvitettiin. Teoreettinen viitekehys rakennettiin asiakaskannattavuuden ja asiakassuhteiden johtamisen ympärille. Tutkimuksen empiirisessä osassa hyödynnettiin kvantitatiivista tutkimusmenetelmää ja tilastollisissa analyyseissä käytettiin laajaa aineistoa. Tulokset osoittivat, että trimmihävikin määrä vaihteli asiakkaiden kesken. Asiakkaista muodostettiin kolme klusteria. Näiden klustereiden tarkempi tutkiminen osoitti selvän yhteyden asiakkaan ostokäyttäytymisen ja trimmihävikin välillä. Lopuksi tutkimuksen tulosten hyödyntämismahdollisuuksia pohdittiin ja myös tutkimuksen rajoitukset tunnistettiin.

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The objective of this master's thesis was to develop a system for measuring the cutting forces of frozen wood. In northern parts of the world cuttingof frozen wood is one of the major problem. During winter and early spring the temperature inside the wood cells will fall below Zero degrees that strongly influences on the properties of the wood. These variations of properties will effects on the blade nomenclature while cutting the frozen wood. However the end results will cause uneven cutting forces. Cutting forces, Chip formation, wearing of the blade and the quality of the machined surface are difficult task. In this project we are attempting to find the variation of cutting forces and properties of frozen wood at four different temperatures (-20 , -10, 0 and + 10 degrees). The linear planning machine was used for measuring the cuttingforces. The cutting was done parallel to the long axis of wood due to the nature of pine wood and the structure of the plane. A considerable amount of work andtime was used for collecting and processing the numerical information from the sensors of the measuring system. There were some alterations suggested to the construction of the plane and the sensor system.

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Laser cutting implementation possibilities into paper making machine was studied as the main objective of the work. Laser cutting technology application was considered as a replacement tool for conventional cutting methods used in paper making machines for longitudinal cutting such as edge trimming at different paper making process and tambour roll slitting. Laser cutting of paper was tested in 70’s for the first time. Since then, laser cutting and processing has been applied for paper materials with different level of success in industry. Laser cutting can be employed for longitudinal cutting of paper web in machine direction. The most common conventional cutting methods include water jet cutting and rotating slitting blades applied in paper making machines. Cutting with CO2 laser fulfils basic requirements for cutting quality, applicability to material and cutting speeds in all locations where longitudinal cutting is needed. Literature review provided description of advantages, disadvantages and challenges of laser technology when it was applied for cutting of paper material with particular attention to cutting of moving paper web. Based on studied laser cutting capabilities and problem definition of conventional cutting technologies, preliminary selection of the most promising application area was carried out. Laser cutting (trimming) of paper web edges in wet end was estimated to be the most promising area where it can be implemented. This assumption was made on the basis of rate of web breaks occurrence. It was found that up to 64 % of total number of web breaks occurred in wet end, particularly in location of so called open draws where paper web was transferred unsupported by wire or felt. Distribution of web breaks in machine cross direction revealed that defects of paper web edge was the main reason of tearing initiation and consequent web break. The assumption was made that laser cutting was capable of improvement of laser cut edge tensile strength due to high cutting quality and sealing effect of the edge after laser cutting. Studies of laser ablation of cellulose supported this claim. Linear energy needed for cutting was calculated with regard to paper web properties in intended laser cutting location. Calculated linear cutting energy was verified with series of laser cutting. Practically obtained laser energy needed for cutting deviated from calculated values. This could be explained by difference in heat transfer via radiation in laser cutting and different absorption characteristics of dry and moist paper material. Laser cut samples (both dry and moist (dry matter content about 25-40%)) were tested for strength properties. It was shown that tensile strength and strain break of laser cut samples are similar to corresponding values of non-laser cut samples. Chosen method, however, did not address tensile strength of laser cut edge in particular. Thus, the assumption of improving strength properties with laser cutting was not fully proved. Laser cutting effect on possible pollution of mill broke (recycling of trimmed edge) was carried out. Laser cut samples (both dry and moist) were tested on the content of dirt particles. The tests revealed that accumulation of dust particles on the surface of moist samples can take place. This has to be taken into account to prevent contamination of pulp suspension when trim waste is recycled. Material loss due to evaporation during laser cutting and amount of solid residues after cutting were evaluated. Edge trimming with laser would result in 0.25 kg/h of solid residues and 2.5 kg/h of lost material due to evaporation. Schemes of laser cutting implementation and needed laser equipment were discussed. Generally, laser cutting system would require two laser sources (one laser source for each cutting zone), set of beam transfer and focusing optics and cutting heads. In order to increase reliability of system, it was suggested that each laser source would have double capacity. That would allow to perform cutting employing one laser source working at full capacity for both cutting zones. Laser technology is in required level at the moment and do not require additional development. Moreover, capacity of speed increase is high due to availability high power laser sources what can support the tendency of speed increase of paper making machines. Laser cutting system would require special roll to maintain cutting. The scheme of such roll was proposed as well as roll integration into paper making machine. Laser cutting can be done in location of central roll in press section, before so-called open draw where many web breaks occur, where it has potential to improve runability of a paper making machine. Economic performance of laser cutting was done as comparison of laser cutting system and water jet cutting working in the same conditions. It was revealed that laser cutting would still be about two times more expensive compared to water jet cutting. This is mainly due to high investment cost of laser equipment and poor energy efficiency of CO2 lasers. Another factor is that laser cutting causes material loss due to evaporation whereas water jet cutting almost does not cause material loss. Despite difficulties of laser cutting implementation in paper making machine, its implementation can be beneficial. The crucial role in that is possibility to improve cut edge strength properties and consequently reduce number of web breaks. Capacity of laser cutting to maintain cutting speeds which exceed current speeds of paper making machines what is another argument to consider laser cutting technology in design of new high speed paper making machines.

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Tämä insinöörityö tehtiin Kuulonhuoltoliitto ry:n Esteetön kuuntelu -projektille. Työ käsittelee kuulolaitteen käyttäjän apuvälineenä käytettäviä induktiosilmukkajärjestelmiä. Induktiivisen äänensiirtojärjestelmän avulla huonokuuloinen saa kuunteluympäristöstään paremman signaali-kohinasuhteen ilman tilan kaikua ja taustahälyä. Tämä helpottaa kuuntelua esimerkiksi puhetilaisuuksissa. Työn tarkoituksena oli päivittää aiempia tutkimuksia kokoamalla uusin tietous induktiosilmukoiden tekniikasta. Kirjallisuustutkimuksen lisäksi kartoitettiin nykyinen silmukkavahvistinkanta haastattelemalla maahantuojia ja jälleenmyyjiä. Silmukkavahvistimien hintakartoituksen tarkoituksena oli rakentaa perusteet sopivan tehoisen ja hintaisen vahvistimen hankintaa varten suunniteltaessa induktiivisella äänensiirtojärjestelmällä varustettavia tiloja. Työ tarkastelee induktiivisen äänensiirtojärjestelmän ensisijaisen kohderyhmän, kuulokojeita käyttävien huonokuuloisten keskeisiä tarpeita ja heidän käyttämäänsä apuvälinetekniikkaa. Työ käy läpi audiotekniikan perusteita, sähkömagneettisen induktioilmiön, induktiivisen äänensiirtojärjestelmän rakenteen, sen ylikuulumisongelmat ja häiriötekijät sekä IEC:n 60118-4 edition 2.0 standardin CDV-luonnoksen mukaiset periaatteelliset asennusja mittausohjeet. IEC:n tuleva standardi tekee työstä ajankohtaisen. Työn tuloksena saatua tietoa voidaan käyttää Kuulonhuoltoliitto ry:n opas- ja tiedotusmateriaalin uudistamisessa, pohjana hyvän kuunteluympäristön malliratkaisujen ja esteettömyyskriteerien soveltamisessa. Työstä on hyötyä erityisesti Kuulonhuoltoliitto ry:n vapaaehtoiskartoittajille kuten myös kenelle tahansa aiheesta syvemmin kiinnostuneelle.

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Summary: Owncontrol directions in meat hygiene legislation and their practical implementation in the slaughterhouse and cutting plant of Snellman Ltd, part I