XI WORLD FORESTRY CONGRESS Antalya, Turkey, 13 to 22 October 1997
	VOLUME 8 E. STUDENT ESSAYS SELECTED FOR THE TRAVEL AWARD UNIVERSITY OF HACETTEPE Occupational High School. Engineering of Wood Industry EFFECT OF SURFACE ROUGHNESS FOR PINUS NIGRA AND PINUS BRUTIA CUT IN TANGENTIAL AND RADIAL DIRECTION Muammer AYSEL and Kerem DOGU Consultant: Prof. Salih ARSLAN ABSTRACT This study has been held to determine surface roughness value occurred after grinding of the tangential and radial cut Austrian pine and Calabrian pine samples using emeries # 40, 50, 60, 80 and 120. During the study, 60 samples were made use of grinned with the aforementioned emeries with 6m/min feeding speed on a roller emery machine prepared on band saw and thickness machine. Grinding process was realised through emery sheets not used previously. A total of 900 testings were realised on the prepared samples using a needle scanning measuring device. Testings were held vertically to the leaves with a needle pin of 5µm radian and on a scannig distance of 12.5 mm (n.c). According to these tests, general arithmetic average of Ra roughness value according to the radial and tangent is Ra=13.65 µm for Austrian pine and Ra=13.18 µm for Calabrian pine. Upon the testings, it has been statistically determined that the cutting type of the tree and grain size of the applied emeries have an impact of surface roughness. It has been also found out that increasing the numbers of emeries reduces the roughness on the surface. INTRODUCTION For cost-benefit analysis in woodworking industry, the most important factor to be taken into consideration is the higher prices of raw materials. Accordingly, it is essential to make optimum use of wood-originated products and semi-products. In addition, an effective factor of marketing the finished products is the post-surface process and is to ensure a maximum reduce in the surface roughness through planing and grinding process, a former process. Production losses have increased due to waste surface -- a result of not conducting surface roughness controls with required devices and methods - and to deficiencies in varnishing and painting. Therefore, in order to minimise the production losses, surface roughness controls are to be conducted with quality control devices developed merely for this purpose. In this study, Austrian pine (pinus nigra arnold) and Calabrian pine (pinus brutia ten) have been cut through radial and tangential directions, grinded with emeries with various numbers, and their surface roughness values have been measured with needle scanning roughness measuring devices. According to the testings held, it has been aimed to determine the surface roughness values of the Austrian pine and Calabrian pine and to assist the researchers in this subject. The surface roughness occurred due to the above-mentioned factors shows its impact on the top-surface and on plastering process. MATERIAL AND METHOD Wooden material used in the research Austrian pine (Pinus nigro Arnold) Austrian pine which is one of the tallest first class forest trees has deep cracks and thick layers on it. The resinous buds are like cylinders and tips are sharp. The thorn leaves are 8 to 15 cm long, dark green and hard. Since the thorn leaves which are at the edges of shoots are forwarded to the buds they look like a calyx. With this peculiarity, at first sight it can be differentiated from scots pine. The pale yellow male flowers of the austrian pine are like cylinders. The effloresce happen in april and may, depending on the region, latitude, altitude and exposition. The female cones are bright, pale yellow, dark colored and grow in two years time. Unlike scots pine the cones are symmetrical and have very short peduncles. The layer is outforward and the body is dark. The scales at the edges of the cones have a spine at their bodies. Austrian pines are located at different places and have varieties each of which has a different name. In our country we have pinus nigra, Coromonica and Pyramidalis all of which are the varieties of the austrian pine. (Aslan, 1994) Austrian pine generally grows in Asia, Thrace, Cyprus, and the Crimea. It is mainly found in Turkey (2.204.381ha). It is found with juniper, beech and oak-tree. They are found in northern Anatolia's inner slopes, In western Anatolia around Dursunbey and at the Taurus Mountains. (Aslan, 1994) Physical and mechanical specifications of the austrian pine Annual ring width is 1.57mm, dry specific gravity is 0,520 gr/cm3, air dry specific gravity is 0,560 gr/cm3, volume density value is 0,456 gr/cm 3, narrowing ratio parallel to the fibres is 0,23%, radial narrowing ratio is 5,58%, tangential narrowing ratio is 8,19%, volumetrically narrowing ratio is 13,9 %, pressure stretching parallel to the fibres is 479kg/cm2 , inclined stretching is 1096 kg/cm2, inclined elastical module 100.000 kg/cm2, dynamic inclined stretching is 0,56 kg.m/cm2, tensile stretching parallel to the fibres is 1113 kg/cm2, tensile stretching vertical to the fibres is 23,4 kg/cm2, crosswise stretching parallel to the fibres on radial direction is 67,1 kg/cm2, tangent direction is 62 kg/cm2, diffusion stretching on radial direction is 8,2 kg/cm2, tangent direction is 9,1kg/cm2. Calabrian pine (Pinus brutia Ten) Calabrian pine is one of our important forest trees which can grow up to 25 m and a have a radius of 60cm. It has thick branches and an irregular body and is similar to Aleppo pine. Yet, it also has some members that grow fast and have a smooth body. Its young shoots are without feathers, thick, its color is initially red, then greenish brown and seldomly dark gray. Its thorn leaves are 15-16 cm. long, smooth and hard, the edges are thin cloved and light green in color. The cones with very short peduncles are approximately 7,2 cm (2,0-12,5 cm) long, with a diameter of 4,1 cm (1,9-5,6 cm) and weigh 40,7gr (2,5-107,9gr) and %4-5 of the fresh cones are pure seeds. The average seed length is 7,02mm (6,09-7,92mm), the seed width is 4,33mm (4,05-4,94mm) and embryo length is 5,51mm (4,84-6,38mm). In general two or three cones stand together in a rigid form. The outer layer is irregularly shaped, the body is pressed and has a brownish color. Egg-shaped seeds are 15-20cm long and have lashed edges and scales are downwarded. It can be differentiated from the Aleppo pine with its cones which have short branches, pressed cone bodies and un-downwarded cone edges. Calabrian pine grows in areas where it is warm in winter and hot and dry in summer. (Aslan,1994) Especially at the sea looking slopes of the hills in the Mediterranean, Aegean and Marmara regions there are wide and uniform calabrian pine forests. In the western black sea region, in some micro-climatic parts that have Mediterranean climax there are small natural hoods. It is the most common tree type in our country and covers an area of 3.096.064ha. Physical and mechanical specifications of the calabrian pine Amongst the pine types that grow in our country calabrian pine has the heaviest wood. Its dry specific gravity is 0,53 gr/cm3, air dry specific gravity is 0,57 gr/cm3, volume density value is 0,478 gr/cm 3. The narrowing ratios are forward direction 0,5%, radial direction 4,9%, tangent direction 6,8% and as volume 12,2%. The pressure resistance parallel to the fibres is 447kg/cm2, inclined resistance is 821,5 kg/cm2, tensile stretching vertical to the fibres is 19,6 kg/cm2, tangential cracking resistance is 5,7 kg/cm2, radial cracking resistance is 5,1 kg/cm2, the calorie value in the body is 4781 col/gr, in the branch 4752 col/gr, in the body skin 4771 col/gr and in the branch skin 4216 col gr. DEFINITION AND IMPORTANCE OF THE SURFACE ROUGHNESS Definition: Surface roughness is the surface irregularities with quite small intervals that occur because of manufacturing methods used and/or other factors, and restricted with other usual irregularities. (T.S.6956) It is impossible to remove the roughness on the surface that is obtained through any kind of manufacturing method (shaping with wood chips or without wood chips). These rough layers can either visible or tactile, and it can also be in sizes that can be measured with sensitive electronic devices. In wood work there are many factors affecting the surface roughness. The anatomical structures, humidity amount and wood defects of trees, rubbing down with emery and emery tools, geometrical shapes and cutting speed of the sharp knives affect the surface roughness remarkably. MEASURING SURFACE ROUGHNESS Various methods have been used for measuring surface roughness. However, in this study, needle scanning method has been used. Needle and its part attached to the main body of measuring device go in and out of the pores on the materials and, thus, the drawing pen records the graphic of the surface. With this measuring methodology, surface roughness of the wood can be measured to a certain extent. Ra (arithmetic average) roughness values are the most common surface parameters, since they present a simple value for acceptance and rejection decision. Ra roughness is the arithmetic average length of roughness disorder measured in a sample length (L) from average roughness line. Ra roughness parameter is calculated with the formula below: Ra=1/Loƒt |y(x)|dx L=length FINDINGS AND RESULTS Table 1 and Table 2 give Ra surface roughness testing average determined upon grinding of Austrian pine samples with emeries #40, 50, 60, 80 and 120 at a fixed feeding speed of 6m/min on radial and tangential section. Table 1. Ra surface roughness values of Austrian pine Ra (mm) surface Tree: Austrian pine General roughness values Emery Numbers Arithmetic Section directions&feeding speed 40 50 60 80 120 Average Radial/6m/min 20.08 19.96 13.80 7.13 6.88 13.57 Tangential/6m/min 18.88 18.46 13.56 9.16 8.66 13.74 General Arithmetic Average 19.48 19.21 13.68 8.14 7.77 13.65             13.65   Ra (mm) Tree: Calabrian pine General surface roughness values Number of emery Arithmetic Section direction &feeding speed 40 50 60 80 120 Average Radial/6m/min 16.20 17.24 10.79 9.31 8.75 12.45 Tangential/6m/min 21.96 16.76 13.69 9.72 7.44 13.91 General Arithmetic Average 19.08 17.00 12.24 9.51 8.09 13.18 13.18     Table 3, 4, 5 and 6 give the results of Duncan test and variance analysis results for above values. Table 3. Variance Analysis Table for Austrian pine Variance Source Degree of Free Total of Squares Square Average Variance Ratio F Table Value Intergroup Intragroup Total 9 141 150 4002.8639 1553.1937 5556.0576 444.7627 11.0156 40.3759 1.88-241   Table 4. Duncan Test Results for Austrian pine Group No   Group Average               Group 9   6.8867 X             Group 7   7.1333 X             Group 10   8.6600 X             Group 8   9.1667 X             Group 6   13.5667 XXX             Group5   13.8067 XXX             Group 4   18.4667 XXXXX             Group 2   18.8812 XXXXX             Group 3   19.9600 XXXXX             Group 1   20.0867 XXXXX             Step 2 3 4 5 6 7 8 9 10 Space 2.80 2.94 3.04 3.11 3.17 3.22 3.26 3.29 3.32   Table 5. Variance Analysis Table for Calabrian pine Variance Source Degree of Free Total of Squares Square Average Variance Ratio F Table Value Intergroup Intragroup Total 9 139 148 3010.9853 832.3880 3843.3733 334.5539 5.9884 55.8670 1.88-241   Table 6. Duncan Test Results for Calabrian pine Group No   Group Average               Group 10   7.4467 X             Group 9   8.7533 X             Group 7   9.3133 XX             Group 8   9.7200 XX             Group 5   10.7929 XXX             Group 6   13.6933 XXXX             Group 1   16.2067 XXXXX             Group 4   16.7667 XXXXX             Group 3   17.2467 XXXXX             Group 2   21.9667 XXXXXXX             Step 2 3 4 5 6 7 8 9 10 Space 2.80 2.95 3.04 3.11 3.17 3.22 3.26 3.29 3.32 · As stated on the tables above the surface roughness value of Austrian pine and Calabrian pine is much more on tangential crosscut than radial crosscut. · The surface roughness value in the smallest radial crosscut is shown at the number 120 emery for both trees. The appraisal results of Austrian pine and Calabrian pine is evaluated statistically. As the variant ratio (40.3759) is bigger than the table result (1.88-2.41), 99% of difference is stated in between the groups. According to this duncan test has been applied in order to match the average. The results in the duncan test has been evaluated as per as of cutting directions and emery types and 10 different groups have been determined for the trees. In Austrian pine; a small difference has been determined as of roughness in between number 120 radial crosscut, number 80 radial crosscut, number 120 tangential crosscut and number 80 tangential crosscut, number 60 radial and tangential crosscut, number 50 radial and tangential crosscut, number 40 tangential crosscut, number 50 tangential crosscut, number 40 radial crosscut. In Calabrian pine; roughness value in between number 120 radial and tangential crosscut, and number 80 radial and tangential crosscut and number 50 radial and tangential crosscut is not high. In Austrian pine the most roughness surface is determined at the number 120 emery radial crosscut where as in Calabrian pine at number 120 emery tangential crosscut. The roughest surface in Austrian pine is at number 40 emery tangential crosscut. The following has been achieved in scope of results gained; The surface roughness is declined as the emery number is increased. The tangential and radial direction difference has been determined in same number emery where as no difference has been determined in other number 50, 80 and 120 emirs. The roughest surface has been achieved at number 80 and 120 when compared to number 40,50 and 60 in Austrian pine than in Calabrian pine. The arithmetical Ra roughness values of Austrian pine is lower than of Calabrian pine. For Austrian pine Ra=13.18µm where as in Calabrian pine Ra= 13.65µm. The emery traces after the emery process has been determined for all numbers. SUGGESTIONS · Radial direction surfaces can be preferred when all conditions are kept constant. · The most suitable surface roughness can be examined for the paste process in different kinds of trees. · The most suitable emery number should be chosen as the emery number increases the surface roughness is decreases. · Less paint and varnish will be used as the most suitable emery process is applied and thus the ideal piece adjustment should be chosen and the emery process should be done neatly. · As the roughness is achieved the paste quality will increase and thus the surfaces should be provided in appreciate roughness value. · The emery panel should be changed in small periods as possible. · The effect of the humidity at surface roughness can be examined. · the mutability of the surface roughness as of different reachable Aries in tree kids. · The wood defaults at the tress would effect the surface roughness negatively and thus under faults trees should be preferred. · The pieces the emery process is supplied should be protected as of damage. · The equipment used should be kept clean. · The surface roughness the wood supplied from different parts of a tree or the most suitable area determination can be examined. 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TS 6212, Aralik 1988, Yüzey Pürüzlülügü - Yüzeylerin Profil Yüksekliginin (Pt) Ölçülmesi, 1st Edition, TSE, Ankara. TS 6956, Nisan 1989, Yüzey Pürüzlülügü - Terimler - Yüzey ve Yüzey Parametreleri Için, 1st Edition, TSE, Ankara. TS 6959, Nisan 1989, Yüzey Pürüzlülügü - Terimler - Yüzey Pürüzlülügü Parametrelerinin Ölçülmesi Için, 1st Edition, TSE, Ankara. Yalçinkaya Ö., 1997, Sapsiz Mese (Quecus Petroeo) ve Karaçamin (Pinus Nigra Arnold) Yüzey Pürüzlülük Degerlerinin Arastirilmasi, Hacettepe University M.S. Thesis, 74 p.   Next Section   Download the Pdf file for this topic   Back to Top of the page
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