抄録
It is reported that a preheating process on hard-to-machine materials is an effective solution to enhance the machining performance. A number of studies have shown that the application of laser as a pre-heating medium significantly improved the tool life and surface quality. In addition, numerous studies in laser assisted micro milling have been reported using a micro end milling tools. However, the material removal mechanism of the micro ball mill tool is far complicated compared to flat end mill or turning process. In this study, the chips formation and machined surface condition of conventional and laser assisted micro ball milling on titanium alloy Ti6Al4V has been observed and compared. Linear grooves machining were conducted at various feeds, depth of cuts and spindle rotational speeds. The air bearing spindle was tilted at 80°. The condition of tools and chips were observed using scanning electron microscope and measuring microscope. It is understood that the tool wear and failure modes are highly influenced by the chips pattern. The application of pre-heating as a softening process of the work piece in micro ball milling process has consequently initiated a drawback such as formation of connected chips and built up edges. Machining with moderate chips length and width is found to be preferable in micro ball milling due to less possibility of chips interference and built up edges formation. Connected chips formation is not recommended in laser assisted machining due to the extreme plastic deformation behavior and excessive cutting temperature generation. Higher depth of cut has produced groves with built up layers at the up milling region. This is due to the poor chips evacuation and large size conical shape of chips.
