Machinability of plantation-grown Eucalyptus globoidea timber

Figures & data

Figure 1. Boring grades: a) Grade 1, b) Grade 2, c) Grade 3, and d) Grade 4.

Table 1. Summary statistics of P. radiata and E. globoidea machinability data. CV: coefficient of variation. Significant differences between species on the 0.05 level are highlighted in bold.

		Eucalyptus globoidea n = 37				Pinus radiata n = 49
		Mean	CV	Min	Max	Mean	CV	Min	Max	P-value
Density (kg/m^3)		723.3	9%	553.7	872.8	460.9	9%	372.4	548.3	< 2.2e-16
Moisture content (%)		12.8	3%	12.1	13.5	12.0	7%	10.2	13.6	1.834e-08
Planing	0.8 cuts/mm	1.9	46%	1	4	1.9	39%	1	4	0.8515
Sanding	1.2 mm	5.0	0%	5	5	1.0	0%	1	1	< 2.2e-16
Boring	Entry	1.0	0%	1	1	1.5	38%	1	3	6.283e-08
	Hole	1.2	32%	1	2	3.1	23%	2	5	< 2.2e-16
	Exit	3.3	32%	2	5	4.1	15%	3	5	3.305e-05
	Overall	3.3	32%	2	5	4.1	15%	3	5	2.401e-05
Mortising	Entry	2.5	32%	1	4	3.4	27%	2	5	4.535e-06
	Side grain	2.5	22%	2	4	3.0	16%	2	4	0.0002647
	End grain	2.4	21%	2	3	4.4	11%	3	5	< 2.2e-16
	Exit	3.5	16%	3	5	4.8	9%	3	5	< 2.2e-16
	Overall	3.6	16%	3	5	4.8	8%	4	5	< 2.2e-16
Grooving	Side grain	1.4	40%	1	3	2.6	20%	1	3	< 2.2e-16
	Corner	1.5	35%	1	2	2.6	19%	2	3	< 2.2e-16
	End grain	2.0	8%	2	3	3.0	18%	2	4	< 2.2e-16
	Exit	2.9	24%	1	4	3.0	23%	2	5	0.5387
	Overall	3.0	22%	2	4	3.3	16%	3	5	0.005251
Edging	Side grain	1.2	59%	1	5	2.1	25%	1	3	8.592e-09
	Corner	2.9	42%	1	5	2.6	34%	1	5	0.1267
	End grain	2.1	27%	2	5	2.9	8%	2	3	5.208e-10
	Overall	3.1	38%	2	5	3.1	17%	2	5	0.8414
Turning	Wedge	2.2	83%	1	5	2.5	78%	1	5	0.5069
	Convex	2.8	51%	1	5	2.9	58%	1	5	0.8597
	Flat	2.7	58%	1	5	3.1	49%	1	5	0.1953
	Concave	2.6	60%	1	5	2.8	63%	1	5	0.7284
	Overall	2.9	47%	2	5	3.2	48%	1	5	0.4370

Table 2. Overall machine scores for E. globoidea and P. radiata according to (ASTM, 2017).

Eucalyptus globoidea
n = 37	Grade 1	Grade 2	Grade 3	Machine Score
Planing	15	13	0	76%
Sanding^a	0	0	0	0%
Boring	0	10	0	27%
Mortising	0	0	17	46%
Grooving	0	8	0	22%
Edging	0	16	0	43%
Turning	0	25	0	68%
Pinus radiata
n = 49	Grade 1	Grade 2	Grade 3	Machine Score
Planing	16	25	0	84%
Sanding	46	0	0	100%
Boring	0	0	0	0%
Mortising	0	0	0	0%
Grooving	0	0	0	0%
Edging	0	1	0	2%
Turning	5	18	0	47%

^a Excellent sanding finish can be achieved at 0.5 mm instead of 1.2 mm depth.

Table 3. Machinability scores for selected processing features of E. globoidea and P. radiata. Problematic processing features are highlighted bold.

		Eucalyptus globoidea n = 37	Pinus radiata n = 49
Boring	Entry	100%	96%
	Hole	100%	18%
	Exit	27%	0%
Mortising	Entry	84%	61%
	Side	97%	90%
	End	100%	0%
	Exit	54%	2%
Grooving	Side	97%	37%
	Corner	100%	37%
	End	97%	12%
	Exit	22%	20%
Edging	Side	97%	78%
	Corner	47%	55%
	End	95%	6%
Turning	Wedge	70%	63%
	Convex	68%	61%
	Flat	70%	47%
	Concave	70%	63%

Figure 2. Example of typical Grade 5 defect on corner caused by edging E. globoidea.

ASTM D1666-17 (2017) Standard test methods for conducting machining tests of wood and wood-base panel materials, ASTM Int.

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