Archive:   VOLUME:   No:   

Volume: 1996/1

Title: Influence of life cycle function on furniture industry products
Author: Darko Motik

The paper is a study on the characteristic functions of a furniture manufacture product\'s life duration. The research was performed in three wood industry firms where all products that meet the research requirements have been surveyed. The research aims were to establish the characteristic curve forms of product\'s life duration, and to select the most frequent forms that occur in both manufacture and sale of furniture; to establish the life duration of the life curve of a wood industry product; to calculate the percentage of the sale per individual phases; to investigate which products realize the highest proportion in the total income. With the presentation of the different curve forms that are available in literature, it was established that beside the known forms of products\' life-duration curves there are also some forms that have not been established so far. The most frequent in wood industry are the cycle/recycle curve forms and the standard ones, while others appear in small numbers. Though there are authors who write of more phases, products\' life-duration generally consists of four interconnected stages: introduction, growth, maturity and decline. The research into the sale phases has resulted in the product quantities for all life phases and is presented graphically. Presented are also the results of products\' duration on the market: average time with these three firms was seven years.

Title: The influence of circular saw natural frequency and excited frequency on the noise emission
Author: Vlado Goglia, Ružica Beljo-Lučić

The paper deals with noise level emitted by circular saw blade at idling. Seven various circular saw blades were tested in laboratory conditions. Damping characteristics of circular saws were tested as well as emitted sound pressure level. Sound pressure level was measured at changing rotational frequences of driving shaft in the range between 25 and 65 Hz. In measurement results the total sound level is shown in dB(A). Frequency analysis of measured sound pressure was made, too. Tests have shovvn high dependence between maximum sound pressure level of emitted noise and circular saw damping characteristics.

Title: Development of moisture content distribution in sapwood and heartwood during initial stages of drying
Author: Georg Bohner, Markus Sacker

45 mm boards of spruce, with high moisture content and parts of sapwood and heartwood, were dried at a temperature of 60°C and at a relative humidity of 77% (dT=5K; Ugl = 12%). The distribution of the moisture content about the cross section was estimated before and after different times of drying. Over a long drying time in the sapwood the humidity was higher than in the heartwood and only at the end of drying sapwood and heartwood reached the same humidity. Also from electrical measurements of the moisture content in the two zones their different behaviour in the drying process can be seen. If a drying process should be carefull, the position of the electrode for the measuring of the moisture content as the controll member of the drying process, is very important. In addition to the observance of the distribution of sapwood and heartwood also the character of the annual rings is to be taken into account.

Title: The production of barrels in Croatia
Author: Milivoj Golub

The barrel is a container which main use is for storage and transportation of liquids, bulk goods and solid materials. Barrels form a group of special wood products-cooperage, i.e. wood containers. Wooden barrels have always been used in the process of wine production and are indispensable items of the wine cellar furniture all over the world. As the wood supply of quality wood is continuously reduced, wooden barrels are today mostly used for ageing of wine, while the containers for the transport and storage of other liquids, bulk goods and solids are made of other cheaper and more convenient materials such as glass, metal and plastics. The best and highly esteemed stave-wood for wine barrels is oak- wood, and penduculate oak of the fine structure which grows amply in Croatia (also known as \"Slavonian oak\") is demanded for the finest cooperage in the whole world. The Slavonian oak is often required for its optimal tannin content and the presence of other aromatic extractives which are an important factor in ageing of quality wines. Oakwood also splits easily (splitting is an important stave - production technique) and exhibits good processing properties. The Croatian tradition in manufacturing of barrels is long and well known in Europe just because of the wood source which is of exceptional physical and chemical properties. There is still enough of best-quality oak in Croatia for the production of barrels and other containers, not only for the home market but also for the export to other markets in the world vvhich show intensive progress in production of wine but where penduculate oak and sessile oak do not grow naturally. Croatia has developed the cooperage industry for production of large-capacity barrels, but there is also a number of craft workshops which manufacture various barrels and other types of container wooden ware.

Title: Utilization of the transportation devices in kiln dryers
Author: Ankica Kos-Pervan, Stjepan Pervan

The manufacturing of drying kilns may sometimes face a difficult task of finding the optimal transport means for dryed wood elements. Such transport means should be suitable for particular demands of the purchase and low in price. The article presents the advantages and disadvantages of the transport means for kiln stacks. Among most usual transport means are trucks, rollerjacks, slide rails, lift trucks, front-end fork lifters, side fork lifters and conveyor trucks (with or without motor) with lifting devices. These are presented regarding the standard types of kiln dryers in which they are employed. The choice of transport means determines the planning of the specific industrial plant since their characteristics must be analysed in terms of general financial possibilities and the optimal role of transport function in the production flow.

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