1 Determination of moisture content of each was measured particleboard moisture content of test pieces.
(1) Weigh the sample before drying specimens weighed immediately after preparation to the nearest 0.01g. If possible, you should take precautions to avoid sawing specimen weighing from moisture during the change.
(2) the specimen into the specimen drying oven at 103 2 ℃ under the conditions of the soil dry to constant mass. 6h interval constant mass is obtained for twice the difference between the moisture content of less than 0.1%.
(3) Weigh the specimen specimen mass after drying After drying to constant mass in a desiccator to cool to room temperature and then weighed, weighing to be fast, to prevent the high moisture content exceeds 0.1%, weighed to the nearest 0.01 go (4) calculating the moisture content rate of specimens of the absolute moisture content of the specimen to the nearest 0.1%.
(5) calculating the moisture content of the board. Test were calculated particleboard sheets single plate or several plates are all equal to the moisture content of the moisture content of the specimen arithmetic mean value is accurate to 0.1%.
(2) Determination of density particleboard were measured MDF and particleboard density of each test piece.
(A) the quality of the specimen in the specimen weighing climate delegated to the constant quality standard, weighing each one specimen quality, accurate to 0.01g.
(2) Measurement specimen measured with a vernier caliper! Length and width of the test piece, the test piece MDF measurement points shown in Figure 1-28, length and width of the arithmetic mean of the two measurements, to the nearest 0. 1mm . Particleboard central specimen specimen measured to the nearest 0. 1mm. Measured with a micrometer thickness of the specimen, using the four-point thickness measurement method (Figure 1-28), were measured at four circle thickness values, accurate to 0. 01mm. Four o’clock arithmetic average of the thickness of the thickness of the specimen to the nearest 0.01mm. Using a micrometer, should micrometer measuring faces slowly put in on the specimen, the applied pressure is 0.02MPa.
(3) calculate the volume of the specimen measured according to the test piece length, width and thickness dimensions, calculate the volume of each test piece, to the nearest 0. Lcm3.
(4) Calculate the density of the specimen test pieces obtained according to the quality of the weighing and the calculated volume of a test piece, the use of density formula to calculate the density of each test piece, accurate to 0.01g/cm3.
(5) Calculate the density of the board were calculated MDF and particleboard specimen density. Two plates with a density equal to all of the test-piece board density arithmetic mean value is accurate to 0.01g/cm3.
(6) the density deviations were calculated in accordance with medium density fiberboard and particleboard density deviation formula to calculate the density of each deviation, accurate to 0.1%.
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3 Thickness Swelling determination: Determination of particle board each specimen thickness swelling.
(1) The initial thickness measurement specimen in the specimen to a constant quality standard climatic decentralized, using a micrometer center of the test piece thickness is measured to the nearest O.Olmm (MDF accurate to 0.05mm).
(2) Soak the specimen into the specimen shelf, immersed in 20 ± 2 ℃ (medium density 25 ± 2 ℃) of water, so that the specimen surface is higher than 20mm, all specimens should be in the same water layer, both not floating on the water, do not sink to the bottom, to have a certain gap between the specimen, left to its own expansion.
(3) the final specimen thickness measurement particleboard specimens immersed 2h or 24h (dry state using general purpose boards for furniture and interior decoration plate soaked 2h, dry or wet state to use the structural panels and reinforced structural panels soaking 24h), MDF specimen immersed 24h, remove the specimen, wipe the surface with water, and immediately measured in the original thickness of the measuring point, beginning with the thickness accuracy. Measuring work must be completed within 30min.
(4) The thickness swelling of the test piece thickness swelling by formula to calculate each test piece thickness swelling, accurate to 0.1%.
(5) Calculation of the board thickness swelling were calculated for each medium density fiberboard and particleboard thickness swelling. A plate thickness swelling equate a full plate specimen thickness swelling on the arithmetic average, this value is accurate to 0.1%. And find a specimen of thickness swelling maximum. Training requirements ① master a variety of instruments and equipment performance, grip procedures, safe operation.
② master moisture content, density, method of measuring thickness swelling.
③ accurate measurement of speed; data processing and reasonable calculation results correctly.