Recently, the demand of carbon fiber reinforced plastics (CFRP) has been rapidly increased in various fields. In most cases, CFRP products requires a finish machining like cutting or grinding. In the case of an end-milling, burrs and uncut fibers are easy to occur. On the other hand, a precise machined surface and edge will be able to obtain by using the grinding tool. Therefore, this research has been developed a novel the cBN electroplated end-mill that combined end-mill and grinding tool. In this report, the effectiveness of developed tool was investigated. First, the developed tool cut the CFRP with side milling. As the result, the cBN abrasives that were fixed on the outer surface of developed tool did not drop out. Next, the end-milled surface of CFRP was ground with the developed tool under several grinding conditions based on the Design of Experiment. Consequently, the optimum grinding condition that can obtain the sharp edge which does not have burrs and uncut fibers was found. However, surface roughness was not good enough. Thus, an oscillating grinding was applied. In addition, the theoretical surface roughness formula in case using the developed tool was formularized. As the result, the required surface roughness in the airplane field was obtained.

Reduction of size and weight are required in a development of machine tools that are mainly used in prototyping purposes. It is generally known, however, that when the reduction of size and weight of the structure were both pursued the machining accuracy can possibly be degraded due to insufficient stiffness. It is important to increase the specific stiffness and thermal stability of a machine tools structure for better machining accuracy. In this study we have applied a sheet of carbon fiber reinforced plastic and a sheet of aluminum honeycomb. A sandwich structure made of both materials and the ribs made of carbon fiber reinforced plastic was proposed. The proposed structure showed the increased specific stiffness and the thermal stability which are suited to the machine tools of high accuracy. We investigated the basic performance of the proposed structure by using several beam-shaped samples, in which the static stiffness and thermal expansion was measured and compared. The inserted ribs in the proposed structure was revealed to be suppressing the thermal expansion of the aluminum honeycomb core. After the basic investigation, a 5-axis machining center with the proposed structure was designed. The mechanical and thermal performance of the structure was tested in the finite element analyses. Finally the machining center was manufactured.