Research On Stability Prediction Of Cutting Processes Based On Complete Discretization Scheme

Dynamics modeling and stability analysis of cutting process are two main subjects in the field of cutting process research. The dynamic modeling reveals the cutting nature from prin-ciple level of cutting process, and provides theorectical foundation to improve the efficiency and quality. Meanwhile, stability prediction of cutting process is also a main researching target, the research of cutting stability is based on regenerative effect, that is two adjacent cutting blades form an uneven cutting thickness and arise chatter, and greately reduced parts surface quality. Therefore, the research of stability of cutting process calculates the combi-nation of process parameters which caused chatter(spindle speed and depth of cut) so as to avoid chatter and to improve both cutting efficiency and precision.This thesis, starting from in-depth researing on cutting thickness model, and presented an improved feed function with the ability of2D curve thickness calculating, extends the scope of thickness model.And then giving a brief introduction on rigid parts-flexible tool model and flexible work-flexible tool model.This thesis focused on the introduction of Complete Discretization Scheme(CDS), and tested CDS by1Degree-of-Freedom(DOF) milling process model, a generally accpeted benchmark method, the results show that CDS has similar calculation precision and show high efficiency over full discretization method and semi discretization method with simple structure. Then, end mill experiments are applied to proof the availability of CDS. Further-more, CDS is also used on stability analysis of sorts of time-delay differential equation, the results prooves that CDS is high-effciency on solving time-delay differential equation.In this thesis, CDS is used to predict the stability of several kind of milling processes, although with different characteristics, but all milling models can be described by delay differential equations and can be calculated by CDS.Experimental research is applied on peripheral milling process, different cutting depth and spindle speed is investigated, the time domain vibration signal and frequency domain signal is analyzed, chatter region and stable region can be identificated, and compared with actural processing photos, the surfaceness characteristics is identical.Realtime surface location error prediction method is added to CDS that making CDS can predict surface error while stability prediction. Finally, CDS is used for stability prediction on turning process and turning experimental verification is applied.