• Claudia B. Caceres
  • Lis Uliana
  • Roger E Hernández Laval University


cutting forces, knots, wood density, surface roughness


Wood defects can cause important loss of raw material and tooling during wood machining. White spruce (Picea glauca [Moench] Voss) is a wood species widely used in Canada, which presents an important occurrence of knots. These knots provoke several problems during machining affecting the final surface quality. The main objective of this research was to evaluate the orthogonal cutting forces and surface quality of white spruce wood with and without the presence of knots. Wood pieces of 12% MC were machined at four rake angles (10°, 20°, 30°, and 40°). Cutting forces and roughness were measured on clear wood (90°-0° cutting direction), knot (90°-90° cutting direction), and surrounding knot areas (before and after knot). Wood density in matched pieces were analyzed by X-ray densitometry. The results showed that the density of knots was in average 2.4 times higher than the density of clear wood. However, cutting forces of knots were up to eight times higher than those of clear wood. For all cutting areas, the parallel force increased as rake angle decreased. However, the sensitivity of cutting forces to changes in rake angle was higher for knots than for clear wood. Furthermore, surface roughness was positively correlated with the cutting forces. The rake angle of 40° produced the smaller cutting forces and lower surface roughness for clear wood, knots, and surrounding knot areas.


Buksnowitz C, Hackspiel C, Hofstetter K, Muller U, Gindl

W, Teischinger A, Konnerth J (2010) Knots in trees: Strain

distribution in a naturally optimised structure. Wood Sci

Technol 44(3):389-398.

Cramer SM, McDonald KA (1989) Predicting lumber tensile

stiffness and strength with local grain angle measurements

and failure analysis. Wood Fiber Sci 21(4):393-410.

Duchesne I (2006) Effect of rotation age on lumber grade

yield, bending strength and stiffness in jack pine (Pinus

banksiana Lamb.) natural stands. Wood Fiber Sci 38(1):


Eyma F, Meausoone PJ,Martin P (2004) Study of the properties

of thirteen tropical wood species to improve the prediction of

cutting forces in mode B. Ann Sci 61(1):55-64.

Hernandez RE, Llave AM, Koubaa A (2014) Effects of

cutting parameters on cutting forces and surface quality of

black spruce cants. Eur J Wood Wood Prod 72(1):107-116.

Huang YS (1994) Cutting force components in orthogonal

cutting parallel to the grain (90-0) I. Effects of rake angles.

Mokuzai Gakkaishi 40(10):1134-1140.

Iskra P, Hernandez RE (2009) The influence of cutting parameters on the surface quality of routed paper birch and

surface roughness prediction modeling. Wood Fiber Sci


Iskra P, Tanaka C (2005) The influence of wood fiber direction,

feed rate, and cutting width on sound intensity during routing.

Holz Als Roh-und Werkst 63(3):167-172.

Jin W, Cai L (1996) Study and analysis on cutting forces of

oblique cutting of wood. Holz Als Roh-und Werkst 54(4):


Kivimaa E (1950) Cutting force in woodworking. Valtion

Teknillinen Tutkimuslaitoksen Julkaisuja, Helsinki, Finland,

Kivimaa E (1952) Blunting of wood-working tools. Holz

Roh Werkst 10(11):425-428.

Ko PL, Hawthorne HM, Andiappan J (1999) Tribology in

secondary wood machining. Pages 101-117 in S Bahadur,

J Magee, eds. Wear processes in manufacturing. American

Society for Testing Materials, West Conshohocken, PA.

Koch P (1964) Wood machining processes. Ronald Press

Co., New York, NY.

Koch P (1972) Utilization of the southern pines, Vol. 2:

Processing. US Department of Agriculture-Forest Service,

Washington, DC.

Koch P (1985) Utilization of hardwoods growing on southern

pine sites, Vol. 2: Processing. US Department of Agriculture-

Forest Service, Washington, DC.

Konishi C (1972) Cutting ability of knife with planer. I.

Relationship between condition of wood and cutting force.

Mokuzai Gakkaishi 18(5):223-229.

Lemieux H, Beaudoin M, Zhang SY (2001) Characterization

and modeling of knots in black spruce (Picea mariana)

logs. Wood Fiber Sci 33(3):465-475.

McKenzie WM (1960) Fundamental aspects of the woodcutting

process. Forest Prod J 10(9):447-456.

Porankiewicz B, Axelsson B, Gronlund A, Marklund B

(2011) Main and normal cutting forces by machining wood

of Pinus sylvestris. BioResources 6(4):3687-3713.

Stewart HA (1969) Effect of cutting direction with respect to

grain angle on the quality of machined surface, tool force

components, and cutting friction coefficient. Forest Prod J


Stewart HA (1970) Cross-grain knife planing hard maple

produces high-quality surfaces and flakes. Forest Prod J


Stewart HA (1977) Optimum rake angle related to selected

strength properties of wood. Forest Prod J 27(1):51-53.

Tabachnick BG, Fidell LS (2007) Using multivariate statistics.

Pearson/Allyn & Bacon, Boston, MA.

Tong QJ, Duchesne I, Belley D, Beaudoin M, Swift E (2013)

Characterization of knots in plantation white spruce. Wood

Fiber Sci 45(1):84-97.

Woodson GE (1979) Tool forces and chip types in orthogonal

cutting of southern hardwoods. USDA Forest

Service, New Orleans, LA.

Woodson GE, Koch P (1970) Tool forces and chip formation

in orthogonal cutting of loblolly pine. USDA Forest

Service, New Orleans, LA.

Zhang SY, Chauret G, Swift DE, Duchesne I (2006) Effects

of precommercial thinning on tree growth and lumber

quality in a jack pine stand in New Brunswick, Canada.

Can J Res 36(4):945-952.

Zhang SY, Koubaa A (2008) Softwoods of eastern Canada:

Their silvics, characteristics, manufacturing and end-uses.

FPInnovations, Quebec, Canada.

Zhou H, Smith I (1991) Factors influencing bending properties

of white spruce lumber. Wood Fiber Sci 23(4):






Research Contributions