ＧＦＲＰの加熱切削

Abstract

In order to reduce the tool wear in cutting GFRP, turning of both pipe and disk of GFRP and drilling of a GFRP plate were carried out under the condition of elevated temperature below 423 K. The pipe was the unidirectional glass fiber reinforced polyester resin, and the disk as well as the plate was the glass cloth reinforced epoxy resin. Both the mechanism of reducing the tool wear and the influence of the cutting temperature on it are considered from the experimental results. The reducing effects of tool wear range from the low cutting speed inducing the relative small tool wear to the high cutting speed inducing the large tool wear directly proportional to the cutting speed. This is based on the decrease of the shear strength and the hardness of the glass fiber, and the decrease of the viscosity of matrix. However, as the bonding between the glass fiber and the matrix also becomes weak at elevated temperature, the condition of the cut surface is not good in many cases. The cemented carbide P 10 showed the remarkable increase of tool wear even at 373 K in heating the tool itself. Consequently, in cutting GFRP with the carbide tool, it is considered that the cutting heat has the two effects, that is, the one is the reducing effect of tool wear due to the variation of the mechanical properties of workpiece, the other is the promoting effect of the tool wear due to the decrease of hardness of the bonding phase of carbide tool and these two effects cancel out. In case of coating tool, the flank wear width decreases with increase of cutting speed. This differs from the case of the cemented carbide tool, the cermet tool and HSS tool.