Laser direct metal deposition (LDMD) is a rapidly emerging additive manufacturing technique offering attractive characteristics like high deposition rates, component repair, and deposition of functionally graded materials. Experimental investigations have been carried out to deposit SS 316L structures at higher deposition rates using LDMD. A continuous fiber laser operating at a wavelength of 1070 nm is used to deposit the structures under different processing parameters like power, scanning speed, and powder feed rate. A power range of 600 W to 1200 W is found to be optimal with speed varying in the range between 10 mm/sec and 25 mm/sec. At low power with higher velocities, a low layer thickness is obtained and vice-versa. With an increase in the power and the decrease in the speed, deposition rates are increased. The findings will help to develop pre-processing, online-processing, and post-processing strategies for LDMD.
The magnetorheological finishing process uses a smart controllable-able fluid known as Magnetorheological polishing fluid, whose yield strength can be controlled externally by varying the magnetic field. The magnetorheological finishing process is capable of providing surface finishing up to the nano-level, but the precision finishing of non-ferromagnetic workpieces like copper and its alloys by using the magnetorheological finishing (MRF) process is challenging. Non-ferromagnetic material repels the applied magnetic field which results in the formation of only one magnetic pole at the tooltip. The magnetic pole at the workpiece surface is distorted by the repelling nature of the non-ferromagnetic materials. So, to finish the surface of nonferromagnetic materials, an axial force is needed to mitigate the repelling effect of nonmagnetic material. In this research paper, a new setup of the Extrusion Based Magnetorheological Finishing process has been designed which can provide the required axial force to the magnetorheological polishing fluid for the precision finishing of the non-ferromagnetic materials.
The current work aims to investigate the feasibility of the novel Maglev (electro-discharge machine) EDM for machining aerospace Ti-grade 5 alloy using urea powder mixed dielectric. The novel setup utilizes the combined effect of permanent and electromagnet to diminish arcing and short-circuiting. The set control parameters were 27 V open-circuit voltage and 1 A peak current while maintaining a duty factor of 95.5%. The dielectric fluid is prepared using urea powder mixed with deionized water at a concentration of 75g/l. The measured discharge voltage and discharge current were 25 V and 200 mA respectively. The machined surface of the workpiece has been analyzed using scanning electron microscopy (SEM) micrograph and energy dispersive spectroscopy (EDS) report. The newly developed Maglev EDM feasibility to machine Ti-grade 5 alloy using urea mixed dielectric has been confirmed in the present work with an average MRR of 0.293 mg/min.
