China
Africa
Explore chapters and articles related to this topic
Machining Process Selection
Published in Hassan El-Hofy, Fundamentals of Machining Processes, 2018
Noise/vibrations: During machining, vibrations and noise components are generated. Noise levels of 85 dB are the maximum noise level regarded as safe and tolerable for an 8 h exposure. When noise levels exceed 90 dB, hearing damage is liable to occur, and therefore earplugs must be worn.
Strategy development for chatter-free milling of Ti-6Al-4V thin-walled surfaces using stability region diagram (SRD)
Published in Machining Science and Technology, 2021
Gaurav Bhakar, Pratik Khandagale, Harshad Sonawane, Suhas S. Joshi
The cutting tool exhibits periodic excitation forces onto the workpiece during a typical machining operation. The workpiece and machine tool system experience vibrations, as a response to the dynamic forces which further result in waviness onto the machined surface, also called as chatter. A chatter mark is an irregular surface flaw left by a wheel that is out of true in grinding or regular mark left when turning or milling at an insufficient stiff machine tool system due to machining vibrations. Among the machine tool system components, the lower rigidity associated to the cutting tool and the workpiece is one of the major concerns as it limits the possibilities of stable machining (Wiercigroch, 2001). The rigidity of cutting tool can be controlled by reducing tool overhang (Mendes de Aguiar et al., 2013; Mishra et al., 2014); however, flexibility associated to thin-wall workpieces remains an issue (Sol et al., 2019). The industrial applicability of thin-walled low rigidity structures is wider and includes applications such as, thin-walled cylinders, axi-symmetric thin-walled components, engine casings, impeller blades, blisks, tombstone fixtures, etc. It is commonly observed that the chatter may get intensified during machining of thin-walled impeller blade like structures. The low stiffness of thin-walled workpieces further gets lowered as the cutting tool progresses onto the workpiece surface with a definite radial and axial depth of cut. This instantaneously varies the dynamic characteristics of tool-workpiece interaction system further affecting the predictability of stability lobe diagrams (SLDs). Significant recent attempts were observed so far addressing the machining issues resulted due to instantaneous reduction of stiffness of thin-walled workpieces along the cut and its subsequent effect on the machining quality.