Wood peeling process monitoring: a comparison of signal processing methods to estimate veneer average lathe check frequency

Denaud, Louis; Bléron, Laurent; Eyma, Florent; Marchal, Roland

doi:10.1007/s00107-011-0549-8

Cited by 17 publications

(12 citation statements)

References 9 publications

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“…As soon as the shear strength of green wood is exceeded, lathe checks appear (Thibaut and Beauchêne, 2004). For homogeneous species like beech, checks are almost periodic (Denaud et al, 2012;Palubicki et al, 2010).…”

Section: Resultsmentioning

confidence: 99%

Analysis of chip formation mechanisms and modelling of slabber process

Pfeiffer¹,

Collet²,

Denaud³

et al. 2014

Wood Sci Technol

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is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. Analysis of chip formation mechanisms and modelling of slabber processAbstract During the primary transformation in wood industry, logs are faced with conical rough milling cutters commonly named slabber or canter heads. Chips produced consist of raw materials for pulp paper and particleboard industries. The process efficiency of these industries partly comes from particle size distribution. However, chips formation is greatly dependent on milling conditions and material variability.Thus, this study aims at better understanding and predicting chips production in wood milling. The different mechanisms of their formation are studied through orthogonal cutting experiments at high cutting speed for beech and Douglas fir. Within these conditions, ejection of free water inside wood can be observed during fragmentation, particularly on beech. As previously seen in quasi-static experiments, chip thickness is proportional to the nominal cut thickness. Moreover, the grain orientation has a great influence on the cutting mechanisms, so as the nominal cut and the grows circles widths. This chip fragmentation study finally allows the improvement of the cutting conditions in rough milling.In order to optimize machine design as well as cutting geometry, a geometrical model of a generic slabber head is developed. This model allows the study of the effective cutting kinematics, the log-cutting edges interactions and the effective wood grain direction during cutting. This paper describes the great influence of the carriage position on cutting conditions. The results obtained here can be directly used by milling machine manufacturers.

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Section: Resultsmentioning

confidence: 99%

Analysis of chip formation mechanisms and modelling of slabber process

Pfeiffer¹,

Collet²,

Denaud³

et al. 2014

Wood Sci Technol

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“…In the peeling process, it has been noted that the compression rate affects the depth and frequency of lathe checks (Lutz 1974); with low compression the rough veneer and deep lathe checks could be formed and with high pressure the spin outs and the tearing of grain could occur (Spelter 1991). According to the literature (Leney 1960), the lathe check phenomenon is almost constant when it is well established, and for homogeneous wood species it could be periodical (Denaud et al 2012;Palubicki et al 2010). Moreover, the lathe checks are supposed to not vary too much as a function of peeling radius except for very low radius where the presence of juvenile wood (exhibiting different mechanical properties) could change the behaviour of the veneer (Darmawan et al 2015).…”

Section: Introductionmentioning

confidence: 99%

“…Lathe check formation and measurement during peeling process have received a lot of attention in the past as well as more recently (Denaud et al 2007(Denaud et al , 2012Tomppo et al 2009;Pałubicki et al 2010;Dupleix et al 2013;Antikainen et al 2015;Darmawan et al 2015). Lathe check depth (LCD) has been measured traditionally by dyeing and evaluating under the microscope (Lutz 1960(Lutz , 1978 in order to identify their effect on product quality (Rohumaa et al 2013;Pot et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Lathe check development and properties: effect of log soaking temperature, compression rate, cutting radius and cutting speed during peeling process of European beech (Fagus sylvatica L.) veneer

et al. 2018

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Denaud. Lathe check development and properties: effect of log soaking temperature, compression rate, cutting radius and cutting speed during peeling process of European beech (Fagus sylvatica L.) veneer. AbstractThe depth of lathe checks and integrity of veneer have been shown to be critical factors affecting the bonding process but also affecting the mechanical properties of veneer-based products. This study shows how beech (Fagus sylvatica L.) veneer lathe checks interval and depths are affected by soaking temperature, compression rate, cutting radius and cutting speed during the peeling process in well-controlled conditions. Freshly felled European beech logs were soaked in a water tank at 50, 60, 70 or 80°C. Following soaking, the logs were immediately peeled with laboratory scale lathe (SEM S500) to 3.5 mm thick veneer at a cutting speed of 1, 2 or 3 m s -1 and pressure rates of 0, 5, 10 or 15%. The correlation between lathe check depth and frequency was validated using "Système de Mesure d'Ouverture des Fissures" (SMOF) device, which enables to measure check properties reliably on veneer ribbons. In a well-controlled peeling process, the strong correlation between check depth and interval was shown. At higher temperature, shallower and more frequent checks are created compared to lower temperature. However, the effect of soaking temperature (between 50-80°C) on veneer checking is much smaller than the effect of compression rate during peeling process, where the higher compression rate produced veneer with shallower and more frequent checks. The results of the study also show that the direction of lathe check propagation could be affected by the rays in beech veneer. Rays resist crack growth in tangential direction, but act as weak planes in radial direction.

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“…There are different frequency ranges associated with the cutting process: high frequencies for tiny cracks at the cell wall level, medium frequencies for lathe check occurrence, and low frequencies for knot severing or transitions from early to late wood. On-line sound measurements can be used to help the monitoring of the process (Denaud et al 2005(Denaud et al , 2007(Denaud et al , 2012. Particularly, lathe check splitting can be measured using a microphone or an accelerometer.…”

Section: Veneer Cuttingmentioning

confidence: 99%

“…Moreover, veneer thickness uniformity is also important, whether for decorative uses or engineered wood products such as plywood or laminated veneer lumber. Thus, the quality of veneers is often the most important parameter in veneer cutting and should be keenly monitored (Denaud et al 2012;Pot et al 2014). …”

Section: The Special Case Of Veneersmentioning

confidence: 99%

Wood machining with a focus on French research in the last 50 years

Thibaut

Denaud

Collet

et al. 2016

Annals of Forest Science

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Abstract& Key message Wood machining is compulsory both for timber separation and the surfacing of wooden objects. The anisotropy, cellular nature and multi-scale level organisation of wood make its cutting complicated to study. During the last 50 years, most of the wood machining subjects were covered by French teams. & Context Woodcutting is a very old technology but scientific research is scarce on the subject. In the last 50 years, much work on basic mechanisms as well as on industrial processes has been done in France. In primary conversion such as sawing, veneer cutting or green wood chipping, huge progress comes from automation and the possibility of linking the process to log and product quality through new sensors. In secondary processing, much has been done on the links between the cutting process, surface qualification and the properties of these surfaces for further processing, such as gluing or coating. Tool wear depends on the cutting process, timber quality and species. Tradeoffs are required in tool technology and coating technologies may improve tool life. & Conclusion A large amount of knowledge and innovation has come from 50 years of worldwide research effort, with France being particularly active in this period. The transfer of skills from metals cutting industry was often a key, but much is needed to move closer to both metal cutting sector and woodcutting skills among craftsmen.

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Wood peeling process monitoring: a comparison of signal processing methods to estimate veneer average lathe check frequency

Cited by 17 publications

References 9 publications

Analysis of chip formation mechanisms and modelling of slabber process

Analysis of chip formation mechanisms and modelling of slabber process

Lathe check development and properties: effect of log soaking temperature, compression rate, cutting radius and cutting speed during peeling process of European beech (Fagus sylvatica L.) veneer

Wood machining with a focus on French research in the last 50 years

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