Orüs-Vezirköprü fabrikasında üretilen yongalevhaların teknolojik özellikleri

Abstract

-127- SUMMARY One of the most important developments in the forest products field has been the manufacture of wood-based panel products. Although among these the particleboard production started latest, its volume surpassed that of the other wood- based panel products. Depeding on the requirements of the field of application the particleboards must have specific properties. Thus, it is necessary that their physical and mechanical properties are investigated to ascertain that the requirements of the applicable standards are met. The purpose of the present study was to determine the technological properties boards produced in the ORUS-Vezir- köprü particleboard factory. The test material, five exprimental boards (18 mm thick, 1830 mm wide, and 3660 mm long) were taken randomly from the normal products of the factory. For each test 10 specimens were prepared from each of the exprimental boards. Thus, each test was made on a total of 50 specimens. The tests were carried out on specimens conditioned at 20+2 C and 65+5 percent relative humudity. The following tests were made according to TS 180 (1978), BS 1811 (1969) and ASTM-D 1037 (1973): thickness control, moisture content, specific gravity (air dry), thickness swelling (2 and 24 hr. immersion in water), bending strength, modulus of elasticity, tension strength parallel to the plane of the board, tension strength perpendicular to the plane of the board, compression strength parallel to the plane of the board, shear strength perpendi cular to the plane of the board, impact strength, janka hardness, screw holding ability perpendicular to the plane of the board and screw holding ability parallel to the plane of the board.-128- The results (arithmetical means) are given below: Thickness control Specific gravity (air dry) Thickness swelling (2 hr.).- Thickness swelling (24 hr.) Moisture content Bending strength Modulus of elasticity Tension strength parallel to the plane of the board Tension strength perpendicular to the plane of the board Compression strength parallel to the plane of the board Shear strength perpendicular to the plane of the board Impact strength Screw holding abitity perpendicular to the plane of the board Screw holding ability parallel to the plane of the board mm 18,36+0,157 gr/cm3 0,640+0,031 % 9,11+1,708 % 12,37+1,329 % 10,52+0,653 kp/cm2 120,19+24,724 kp/cm2 12334,50+1984,820 kp/cm 45,50+8,224 kp/cm2 4,79+1,409 kp/cm2 85,41+23,567 kp/cm2 40,49+4,762 mm 381,44+45,226 kp 52,71+10,618 kp 40,90+7,131 Thus, particle boards tested comply with the Turkish Standard, T5 180, in their specific gravity, maisture content, and tension strength perpendicular to the plane of the board, but not in their thickness swelling and bending stregth. To reduce the thickness swelling it is recommended to add 0,5 %- 1 % paraf fin (based oh the o.vendry weight of the chips). To satisfy the requirements for bending strength it is necessary that the particle geometry be adjusted and the thicknesses of the core and face layers rearranged taking into account the thickness of the boards.