The chips generated during up-milling and down-milling of pine wood by helical router bits

Abstract

Machining aspects with helical edge router bits (helix angle 15°, 30°, 45°, and 60°) with a cutting circle diameter of 8 mm were studied. The purpose of the research work was to investigate chip formation and surface roughness characteristics in milling pine wood by the straight and helical edge bits. The chips generated could be classified into four types by sieving into spiral chip (5 mesh), flow chip (10 mesh), thin chip (30 mesh), and granule chip (< 30 mesh). The experimental results show that spiral chips were generated most often (on a weight percentage basis) by the bits during down-milling process. More flow and thin chips were produced by the bits during up-milling process. Better surface roughness was produced by bits during down-milling compared to up-milling. With increasing helix angle of the bits, the amount of spiral and flow chips increased and granule chips were reduced. The machined surface produced was better in roughness (lower Ra values) as the helix angle of the bits increased both in up-milling and down-milling processes.