Investigations on the Impact of Additively Manufactured Coolant Channels and Outlet Nozzles on Free Jet and Jet Forces in High-Pressure Cutting Fluid Supply
9 Pages Posted: 6 Oct 2021
Date Written: December 1, 2021
The focused high-pressure cutting fluid supply into the contact zone between the rake face of a cutting tool and the emerging chip helps to increase tool life and to improve chip evacuation. Moreover, the productivity of the cutting process can be increased due to higher applicable cutting parameters. Traditionally manufactured milling tools feature drilled coolant channels with sharp intersections, causing pressure losses between channel inlets and outlets. Moreover, the resulting turbulences lead to an undesirable expansion of the cutting fluid free jet. Additive manufacturing technologies, such as Laser Powder Bed Fusion (LPBF), allow an enhanced freedom of design. Thus, the technology enables the manufacturing of cutting tools with flow-optimized coolant channels that feature smooth radii transitions and nozzles specifically designed for the application. In this paper, a novel test bench for analyzing the cutting fluid free jet and jet forces under high-pressure cutting fluid supply with additively manufactured coolant channels with different channel geometries as well as different outlet nozzles is presented. Furthermore, the impact of post-processing the inner surfaces by means of abrasive flow machining is investigated. The results are compared with computational fluid dynamics (CFD) simulations. The investigations show that flow losses in additively manufactured and geometry-improved coolant channels can be decreased in comparison to traditionally drilled channels. Further, the fluid free jet expansion can be reduced depending on the nozzle design. The cooling and lubrication can be enhanced due to a more focused cutting fluid supply and higher flow velocities.
Keywords: cutting tool; coolant channel; high-pressure cutting fluid supply; flow optimization; computational fluid dynamics; additive manufacturing; Laser Powder Bed Fusion
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