LY/T 3136-2019Test method of rotary veneers drying quality (English PDF)

4.1 Veneer moisture content

Measured in accordance with 4.3 of GB/T 17657

4.2 Distribution of moisture content in dry veneer

4.2.1 Sampling and numbering

On the dry veneer tape, randomly select no less than 3 test veneers, and the size is the size in the fiber direction.

Degree dimension, the dimension in the vertical fiber direction is not less than 700mm;

The specification of the moisture content test sample is about 100mm × 100mm.

On each test veneer, label the veneer samples according to the numbering method shown in Figure 1;

Separate size is not less than.200mm, in vertical the size of the gap in the fiber direction is not small at 100mm.

In millimeters

4.2.2 Instrument

According to 4.3.2 of GB/T 17657.

4.2.3 Detection method

Test in accordance with GB/T 17657, 4.3.3.

4.2.4 Calculation method of moisture content distribution of dried veneer

The calculation of the moisture content distribution of the dried veneer is performed according to formula (1).

Where. (ij)-moisture content of the veneer at position (ij),%;

LY/T ××××-××××

G0 (ij)-the absolute dry mass of the veneer sample at position (ij), the unit is gram (g);

G1 (ij)-the initial mass of the wet veneer sample at position (ij), the unit is grams (g);

i- the number of the sample in the vertical fiber direction;

j- the number of samples in the direction of the fiber.

4.3 Average moisture content of dry veneer

4.3.1 Sampling and numbering

In accordance with the provisions of 4.2.1.

4.3.2 Instrument

According to 4.3.2 of GB/T 17657.

4.3.3 Detection method

Test in accordance with the test method of 4.1.3.

4.3.4 Calculation method of average moisture content of dry veneer

The calculation of the average moisture content of the dry veneer is performed according to formulas (2), (3), and (4) (any one is sufficient).

Where.-the average final moisture content of the dry veneer, (%);

G0 (ij)-the absolute dry mass of the veneer sample at position (ij), the unit is gram (g);

G1 (ij)-the initial mass of the veneer sample at position (ij), the unit is. gram (g);

4.4 Uniformity of moisture content of dried veneer

4.4.1 Sampling

On the dry veneer tape, randomly select no less than 9 test veneers, and the size is the width of the veneer tape in the fiber direction.

Degree dimension, the dimension in the direction of the vertical fiber is not less than 700mm.

4.4.2 Instrument

According to 4.3.2 of GB/T 17657.

4.4.3 Detection method

Test in accordance with GB/T 17657, 4.3.3.

4.2.4 Calculation method of moisture content uniformity of dry veneer

The calculation of the uniform moisture content of the dry veneer is performed according to formula (5).

In the formula.

- Uniformity of moisture content of dry veneer, (%);

- Maximum value of the average moisture content of the selected dry veneer (%);

- Minimum value of the average moisture content of the selected dry veneer, (%).

4.5 Drying veneer deformation

4.5.1 Test specimen

Samples of veneer are randomly selected in the dry veneer, and the specifications are that the size in the fiber direction is the width of the veneer strip, and the vertical fiber the direction is the natural width of the veneer.

4.5.2 Measurement method

Place the dry veneer flat on the horizontal operation platform, and the corner feet on both sides of the measured end face must be in contact with the horizontal operation platform;

Use a ruler with a length of >=2000mm (accuracy >=1mm) to measure the horizontal dimension of the veneer in the direction of the horizontal stripes, L, as shown in Figure 2;

Using a ruler with a length >=2000mm (accuracy >=1mm), measure the maximum arch height dimension at the end of the veneer, H, as shown in Figure 2.

4.5.3 Calculation

The calculation of the deformation and warpage of the dry veneer is performed according to formula (6).

Where. gamma-dry veneer warpage;

H-maximum arch height before and after drying, unit. millimeter (mm);

L-Horizontal horizontal dimension of the veneer before and after drying, the unit is millimeter (mm).

4.6 Cracking of dry veneer

4.6.1 Test specimen

In accordance with the provisions of 4.5.1.

4.6.2 Measurement method

On the sample, measure the length and number of cracks with a ruler with an accuracy of 1 mm, and record.

4.6.3 Detection content

Number of cracks

Cumulative length of crack Crack average length

4.6.3 Calculation

The calculation of the cumulative length of dry veneer cracking is performed according to formula (7).

In the formula.-Cumulative cumulative length, unit. millimeter (mm);

-The nth cracking length in millimeters (mm);

The calculation of the average crack length of the dry veneer is performed according to formula (8).

Where.-average crack length, unit. millimeter (mm);

-The nth cracking length in millimeters (mm);

n-number of cracks.

Appendix A

(Informative appendix) Dry veneer crack detection record sheet Species. Origin. Ambient temperature. °C Ambient relative humidity.% Specimen number cracking number cracking length mm Cumulative length of crack mm Crack average length mm Date inspector. auditor