دانلود رایگان مقاله مدل سازی تحلیلی در تشکیل تراشه سه بعدی سطح دوار

ABSTRACT

Orthogonal turn-milling is a relatively new process technology, the coupling turning and milling processes together and enjoying the advantages of both. However, to the best knowledge of the authors, few studies on the chips of the orthogonal turn-milling have been reported, although the understanding of the chips is important when studying turnmilling mechanism, machining heat and tool wear. In this paper, the analytical models of 3D chips (under both centric and eccentric situations) are proposed based on the orthogonal turn-milling principle and the mathematical expressions of chip thickness and height are obtained considering both side and end cutting edges. Based on the models, numerical analysis is performed to understand the relationships between chip dimensions and cutting parameters. To verify the proposed models and numerical results, the validation experiments are conducted. The comparison shows the consistency between theoretical and experimental results in terms of chip geometries and volumes under different cutting speeds and feed rates. Some findings are presented based on this study, which might provide a theoretical foundation and reference for the orthogonal turn-milling mechanism research.

6. Conclusions

In this paper, two mathematical models (for centric and eccentric situations) of chips are proposed depending on orthogonal turn-milling principle. We conclude mathematical expressions for chip thickness and height, considering both the side cutting edge and the end cutting edge, respectively. Several new findings may be summarized as followed:  According to the relation between eccentricity and axial feed, it shows that, when jej = r  ls, the maximum axial feed is gained, which reach maximum machining efficiency and the workpiece shape accuracy in industrial production. Moreover, the side cutting edge plays a dominant role in eccentricity condition, and the end cutting edge is hardly involved in actual cutting process.  No matter how much the eccentricity is, chips are consists of two parts. One is created by side edge, the other is generated by end edges. Meanwhile, the cross-section profile of chips is a function of engage angle during processing (in the constant machining condition). Chip thickness is always changing along the direction of the cutter rotation and cutting edge radius has a greater impact on the finishing machining.  Chip dimensions are affected by various cutting parameters and the influence laws are studied by simulation and experiments. It is shown that when eccentricity is equal to zero, the entry cutting angle almost start for the end cutting edge and the side cutting edge simultaneously, but the end cutting edge exits from the workpiece before the side cutting edge; In the whole cutting range, the side cutting edge moves to the entry zone, and the end cutting edge will move to the exit zone with the increase of eccentricity. The chip thickness of the side cutting edge and chip width of the end cutting edge increase obviously increases in feed rate.  3D chip geometry model matches with experiments well. So it is with analytical chip volumes and experiments in different cutting speed and feed rate. Actually, the volume of chip decreases with increase in milling-speed in noneccentric and eccentric position, but volume of chip decreases with increase in milling-speed in non-eccentric and eccentric position.