Abstract
This study attempted to reduce the crack on machined surface for Polybenzimidazole (PBI) in slow cutting speed by using orthogonal tool under laser assisted machining (LAM). As traditional cutting method causes the crack on the surface usually, strength of PBI decreases as compared with inherent. Though the condition that cutting temperature is approximately 693K can reduce the crack, it requires extremely fast cutting speed as 2400 m/min, so it's difficult to realize this method in general machine tool. From this experiment, LAM indicated fluid area where there is no crack on surface although cutting speed is as slow as 500 mm/min. In addition, laser irradiation to local area didn't cause heat influence at machined surface. Bringing the laser spot close to the tool is effective in order to spread this fluid area. However, method of changing laser diameter is better way than it for changing distance between laser and tool. As the larger the spot diameter is, the more the temperature becomes uniform, the area of crackless is increased.
