Modeling And Experimental Study On Burr Formation Process In Micro-milling

In recent years, the demand in micro manufacturing has been increasingrapidly. Owing to its advantages in processing complicated3-D parts over largescope of materials with high efficiency, micro-milling, a new technology derivedfrom the conventional milling processing method, has raised widespread attentionsamong the academia and industry. However, relatively massive burrs have beendetected during micro milling ductile materials. The subsequent deburring processis still a major challenge and is not profitable and still difficult to achieve. Betterunderstanding on the burr formation process and thus being able to minimize andprevent burr formation during the manufacturing process is necessary andpromising. Focusing on studying the burr formation in micro milling on Ti-6Al-4Vvia finite element modeling and experiments, the burr formation process and itsinfluencing factors have been investigated in this paper.Through building3-dimensional finite element models of micro-millingoperation, the minimum chip thickness effect, cutting force and temperature havebeen modeled. The formation process of typical burrs generated in micro-millingwith flat end and ball end tools has been simulated, and they are classified asentrance burr, exit burr, up-milling top burr and down-milling top burr. A new typeof burr has been detected from the modeling of the micro-ball-end-milling. Burrmorphologies were verified via experiments to validate the proposed finite elementmodel. Based on this, focusing on the micro-end-milling, the impacts of cuttingparameters and cutting tool edge radius on burr formation have been investigated.Flat end tool models with various radial rake angles and helix angles have beenestablished, and the burr formation in micro-milling with these cutting tools weremodeled. Micro-milling experiments have been conducted to investigate the impactof cutting parameters on the finishing quality and top burr size. Further orthogonalexperiments with different cutting parameters have been carried out to validate theconclusion of the correlation between cutting parameters and top burr size drawnfrom modeling. Accordingly, focusing on micro-ball-end-milling operation, theimpacts of cutting parameters and cutting tool edge radius on burr formation have been studied through simulation. Some new ball end tool configurations withdifferent normal rake angles have been designed, and modeling on micro-millingoperation with these tools has been done to investigate the stress distribution,cutting force and burr formation. Micro-ball-end-milling experiments have beenimplemented to investigate the impacts of cutting parameters and tool wear onfinishing quality. Further orthogonal experiments with different cutting parametershave been carried out to investigate the role of cutting parameters in top burrformation. Five-axis machining experiments have been conducted to investigate theimpact of feed pattern and the tool inclination angle on finishing quality and burrformation. A novel burr was detected lying on the slot base both in modeling andexperiments. The results indicate that ball end tools are capable to suppress top burrformation in micro milling, and that burr minimization during cutting can beachieved via processing optimization. This work may provide instructions andreferences on burr minimization in micro-milling practice and new micro cutterdesign.