Kvaliteta bukove hlodovine in izkoristek pri luščenju furnirja

diplomsko delo (visokošolski strokovni študij)

Peter Mihič (Avtor), Željko Gorišek (Recenzent), Katarina Čufar (Mentor), Dominika Gornik Bučar (Komentor)

Povzetek

Spremljali smo kakovost lesa bukve (Fagus sylvatica L.) v procesu proizvodnje luščenega furnirja od prevzema in krojenja hlodovine, luščenja furnirja, krojenja na mokrih škarjah, sušenja in krojenja na suhih škarjah. Spremljali smo izgube in predlagali rešitve za njihovo zmanjšanje. Podatki o prevzemu hlodovine na skladišču surovin in razvrščanje v kakovostne razrede kažejo, da se kakovost hlodovine v zadnjih 5 letih nekoliko poslabšuje. Analiza odčelkov,ki nastajajo pri krojenju hlodovine, kaže, da se največji izmet pojavi zaradi čelnih razpok, zaradi sprostitve notranjih napetosti. Računalniško vodeno krojenje hlodovine bi zmanjšalo izmet. Pri računalniško vodenem luščenju nastopi največji izmet zaradi zaokrožitve hlodov, ostankov od luščenja in zaradi dolžinske nadmere krojenih hlodov. Pri krojenju furnirja na mokrih škarjah avtomatski optični čitalniki zaznajo le napake, ki jih je mogoče presvetliti, ne pa napak v barvi ali teksturi lesa. Slednje odpravljamo pri krojenju na suhih škarjah, ko je furnir že posušen. Pri računalniško vodenem sušenju furnirja na valjčnem pretočnem sušilniku volumskokrčenje furnirja znaša 12,6 %, kar je v mejah pričakovanega. Kakovost posušenega furnirja močno odraža kakovost surovine, saj napake zaradi notranjih napetosti, tenzijskega lesa in grč v postopku sušenja povzročajo gubanje, zvijanje in pokanje furnirja. Krojenje suhega furnirja je odvisno od namena uporabe. Furnirji za zunanje sloje morajo biti kvalitetnejši in brez napak.

Ključne besede

bukev (Fagus sylvatica L.);hlodovina;furnir;luščenje;izkoristek;

Podatki

Jezik:	Slovenski jezik
Leto izida:	2006
Izvor:	Ljubljana
Tipologija:	2.11 - Diplomsko delo
Organizacija:	UL BF - Biotehniška fakulteta
Založnik:	[P. Mihič]
UDK:	630*826.1
COBISS:	1403785
Št. ogledov:	1277
Št. prenosov:	303
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Angleški jezik
Sekundarni naslov:	ǂThe ǂquality of beech wood and exploitation of peeled veneer
Sekundarni povzetek:	Quality of beech (Fagus sylvatica L.) wood was studied through different phases of peeled veneer production. These phases included control of logs at the timber-yard and their cutting (shortening), as well as veneer peeling, its cutting on wet shears, drying, and cutting on dry shears. The loss of raw material in each of the phases was determinated, and solutions for its reduction recommended. The results show that the quality of supplied raw material has been decreasing over the period of the last 5 years. The analysis of cut logs reveals that the biggest losses occur due to released growth stresses. The computer controlled cutting of logs can reduce these losses. A majority of losses caused during the computer controlled peeling is due to rounding of the logs, because of inability to use the central parts of the logs remained after peeling, and in case the logs are oversized (too long). The veneer is checked with optical scanners before cutting on wet shears. The scanners recognize only the defects that transmit the light, but they cannot detect the ones in wood colour and grain. The volume shrinkage of the peeled veneer during drying is 12.6 %, which is expected. The quality of dry veneer proved to be in acordance with the quality of the raw material. The defects like growth stresses, tension wood, and knots provoke twisting and splitting of the veneer in the process of drying. Final cutting of the veneer on dry shear depends on its end use. The veneer for outer layers of the plywood needs to be of the highest quality and without defects.
Sekundarne ključne besede:	beech (Fagus sylvatica L.;log;veneer;peeling the veneer;exploitation;
Vrsta dela (COBISS):	Diplomsko delo
Strani:	XI, 71 f.
Ključne besede (UDK):	applied sciences;medicine;technology;uporabne znanosti;medicina;tehnika;agriculture and related sciences and techniques;forestry;farming;wildlife exploitation;kmetijstvo ter sorodne vede in tehnologije;forestry;gozdarstvo;forest products and their utilization;gozdni proizvodi in njihova uporaba;
ID:	21001