Engineering Faculty Internship: Modeling of the Two-Dimensional Chip Breaking Process for Maching with a Grooved Tool Insert

本文的工作是建立一种新的切削力模型，用于传统槽型刀片加工中的切屑断裂。这预计将使用最近建立的用于用平面(非切屑成形)工具进行加工的力模型来实现。建议的工作将涉及对切屑折断过程的分析建模，在需要考虑切屑自由端以及切屑槽后壁处的附加力的条件下。在切屑/刀具后壁和切屑/工作面接触点假设摩擦条件可变。著名的金属切割剪切面理论将被推广，以包括上述附加摩擦力的影响。实验工作将包括使用高速摄像系统研究典型断屑周期内不同的切屑卷曲和断屑模式，同时使用三分量刀具测功机系统连续监测切削力的变化。在分析模拟和实验工作的基础上，期望采用连续变化切屑载荷的有限元建模技术对卷曲切屑进行建模。将估计机械性能的变化，例如通常导致切屑折断过程的拉伸应变。这项工作的主要目标是确定影响切屑折断的最重要因素，并根据新的发现开发新的切屑折断判据。希望该项目中预期的新发现将有助于刀具制造商设计新的和创新的切屑成形刀具刀片。

This proposed work is to develop a new cutting force model for chip breaking in machining with a conventional grooved tool insert. This is expected to be accomplished using a recently established force model for machining with a flat-faced (non-chip forming) tool. The proposed work will involve analytical modeling of the process of chip breaking process for conditions requiring consideration of additional forces at the free-end of the chip as well as at the back-wall of the chip groove. Variable frictional conditions will be assumed at the chip/tool back-wall and chip/work surface contact points. The well known shear plane theory of metal cutting will be extended to include the effects of the above additional friction forces. Experimental work will include the use of a high speed filming camera system to study the varying chip curling and breaking patterns within a typical chip breaking cycle while continuously monitoring the cutting force variations with the use of a three-component tool dynamometer system. Based on the analytical simulations and the experimental work, it is expected to model the curled chip using the finite element modeling technique for continuously varying chip loading. The variation of mechanical properties such as the tensile strain which normally contribute to the chip breaking process will be estimated. The major objective of this work is to establish the most significant factors that influence chip breaking and to develop a new chip breakability criterion based on the new findings. It is hoped that the new findings anticipated in this project will help cutting tool manufacturers in designing new and innovative chip forming tool inserts.