ANALYSIS OF SURFACE ROUGHNESS OF BLACK ALDER AS FUNCTION OF VARIOUS PROCESSING PARAMETERS

The objective of this study was to analyse thesurface quality of black alder (Alnus glutinosa)samples as function of sanding processes based onfour grits sizes, namely 60, 80, 100 and 120. Thesanding process was performed parallel,perpendicular and at 45 degrees angle to the grainorientation of the specimens. The experiments werecarried out on a wide belt sanding machine atNIKMOB Nehoiu Company. Two machiningvariables, feed speed and cutting depth were usedfor the tests. Two roughness parameters, Rk(processing roughness parameter) and Rpk (fuzzygrain roughness parameter) were determined byemploying the optical profilometer type MicroProfFRT, on dry and wett areas of the samples. All datawere processed by using a nonlinear regressionmethod respecting an equation of 2nd degree typewith two variables. The ANOVA analysis was alsoused to evaluate the data by applying fiveindependent variables, namely: sanding program,sanding direction, feed speed and cutting depth forthe two statement of surface, with and withoutwetting. The results of the study revealed that thewetting of samples did not show a better quality ofsanded surfaces. However when the samples weresanded at 45 degrees angle and parallel to the grainorientation, overall surface quality of the samplesimproved compared to perpendicular direction. It wasalso found that the cumulative effect of factors wasmore representative on the roughness parametersthan the situation when taken individually. It appearsthat based on the findings in this work suchapproach can be successfully applied in woodproducts industry including furniture manufacturing tohave a more efficient use of the raw material infurther processing steps such as finishing.