Автор: Anastasija Temelkova
Статии
- IMPACT OF FEED RATE ON ROUGHNESS OF THE CUT SURFACE AND ENERGY CONSUMPTION DURING CUTTING DRY BEECH WOOD WITH A CIRCULAR SAW
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Резюме
The feed rate during mechanical processing of wood is one of the factors that has a high influence on the roughness of the cut surface and energy consumption.
The roughness of the cut surface caused by traces of the cutting tool has an influence on the hydrothermal treatment and all other mechanical treatments of the wood. Greater roughness, due to faster evaporation of moisture from the wood, increases the percentage of drying errors. On the other hand, higher roughness values decrease the lumber yield.
Energy consumption is an indicator of the cutting resistance and it depends directly proportionally, or inversely proportionally when the thickness value of the sawdust is less than 0.1 mm. At the same time, the teeth do not cut the wood and they do not create sawdust but wood dust.
In this research, three different feed rates were applied (U1=12 m·min-1, U2=16 m min-1 and U3=20 m·min-1) for a constant cutting height of 45 mm in dry beech wood with moisture content W=10±1%. The measurements were made with a circular saw with diameter of cutting tool D=250 mm, number of teeth Z=40 and width of the cut b=3,2 mm. The number of rounds was n=5500 min-1.
Roughness measurements were taken with a digital comparator, according to the Rmax criterion.
Measurement data for energy consumption were taken with a clamp amperemeter.
The obtained results showed a pronounced significance, directly proportional dependence of the roughness of the cut surface and energy consumption on the feed rate.Ключови думи: beech wood, circular saw, roughness, energy consumption, the feed rate
- PROCESSING SAWLOGS INTO PARQUET BLANKS
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Резюме
The term parquet refers to a floor covering made of solid wood, consisting of interconnected slats in a horizontal plane. A parquet strip is the principal constructional element of the parquet. This wooden strip is obtained as a result of processing the flooring blank. In the sawmill processing of the sawlogs, the flooring blanks are sawn from the sawlogs, mostly in the radial and tangential direction. For such a purpose, sawlogs from domestic species and foreign species are used. Most dominant in this manner are the hardwood species, although softwood species can be used too. Among the domestic species, the most are beech, oak, acacia, elm, ash, and from the softwood species pine and larch.
The paper focuses on the maximum quantitative yield of beech and oak sawlogs intended for processing into parquet blanks. The sawing was conducted on a bandsaw. The blanks were with a thickness of 25,0 mm. The sawlogs belonged to the I, II, and III quality classes. A total of 12 sawlogs were processed, 6 from beech (Fagus sylvatica L.) and 6 from oak (Quercus robur). All sawlogs were with a constant length of 3,0 m. The mean diameter for beech and oak sawlogs was in the range of 34,0 to 36,0 cm.
The average value for the quantitative yield for beech sawlogs from I, II, and III quality classes was 37.90%. For the oak sawlogs from I, II, and III quality classes the average value of the quantitative yield was 39.40%.Ключови думи: beech, oak, sawlogs, maximum quantitative yield, quality class, parquet blanks