| Abstrakt: |
This paper describes research results about machining properties of nyerakat (Hopea cenua Teijsen & Binn.) and resak (Vatica spp.) woods, originated from West Kalimantan. This research aimed to look into the machining properties of those two wood species. Testing of wood-machining properties referred to the modified standard of ASTM D-1666-64. The examined machining properties (machinability) related to the planing, shaping, boring, turning, and sanding actions. Air-dry defect-free boards (of those two woods), which measured 120 cm by 12.5 cm by 2.5 cm, were used to prepare the test specimens. Number of main samples for each species was 20 defect-free boards. For any species, meanwhile, number of testing samples for each of the machining properties and each of their moisture contents were 20 wood specimens. Observations on machinability were performed visually using loupes, with 10-time magnification. Results disclosed that kinds as well as number of defects and defect-free values. Kinds of fuzzy grain defects were found on both species, which resulted from those five machining actions. Nyerakat woods exhibited defect-free values at 71.5%, 77.25%, 90.75%, 81.5%, and 90.75% (due to consecutively planing, shaping, boring, turning, and sanding). Meanwhile, the corresponding defect-free values for resak woods were 80% (due to planing), 86% (shaping), 88.25% (boring), 79.5%, (turning) and 88.25% (sanding). Accordingly, nyerakat woods afforded very good machining qualities associated with boring, turning, and sanding actions were very good, hence categorized as class I; meanwhile, concerning the planing and shaping, the machining qualities were good, regarded as class II. For resak woods, the machining qualities concerning the shaping, boring, and sanding were judged as very good (as class I); while the qualities concerning the planing and turning belonged to consecutively good and very-good-to-good category, as classes II and I-II, respectively. Those two wood species were recommendable for processing into varying wood-working products with machining qualities, e.g. indicatively good until very good. [ABSTRACT FROM AUTHOR] |
