In the manufacturing industries, it is a standard procedure to heat the logs to soften them before the peeling process, generally achieved by immersing the whole logs in a hot water bath or by steaming them in vats, using water as the medium to transfer heat to the log (Denaud et al., 2007), a procedure that results in both the production of veneer sheets that are smoother with lesser lathe checks (Dupleix et al., 2012) and a production process that is less energy-dependent (Marchal et al., 2004). Researchers have carried out studies on the formation of veneer lathe checks during the log peeling process and indicated that the depth of lathe checks reduces at a higher temperature (Tomppo, Tiitta and Lappalainen, 2008; Pałubicki et al., 2009; Dupleix et al., 2012; Antikainen, 2015; Denaud et al., 2019). However, higher temperature makes the logs softer during the peeling and leads to irreparable changes that affect plywood bond strength (Rohumaa et al., 2017). The log heating times and temperatures can affect hardwood species differently. The aim of this research is to study the effect of the log soaking duration and temperature on lathe check development and veneer crosswise tensile strength of different hardwoods.
Keywords: lathe check, crosswise tensile strength, pith, bark, veneer, log soaking
Authors
Heikko Kallakas
Tallinn University of Technology, Department of Materials and Environmental Technology, Laboratory of Wood Technology, Ehitajate tee 5, 19086 Tallinn, Estonia
Anti Rohumaa
Laboratory of Wood Technology, Department of Materials and Environmental Technology, School of Engineering, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia
Jaan Kers
Department of Materials and Environmental Technology, Tallinn University of Technology, Estonia
Onyekachi Fortune Nwokocha
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