On the effects of cutting-edge angle on high-feed turning of Inconel 718© superalloy

Machining processes on heat-resistant superalloys—i.e., turbine cases, rings, or shafts—are challenging tasks. The high-added value of such parts makes cycle times be longer than expected. Recently, high-feed turning technique has attracted the attention of practitioners due to its high material removal rate capability. PrimeTurning™ tool unifies the concepts of high-feed and multidirectional turning using multiple active cutting edges. It should be capable of reducing machine downtimes in that kind of parts. However, to avoid early tool replacement and rejects on high added value parts, a deeper knowledge on the high-feed turning process is necessary. Here, inserts specifically designed for high-feed turning in heat resistant Inconel 718© alloy were tested using three cutting-edge angles. The results showed that when chip thickness is more relevant, a cutting-edge angle of 30° reduces the likelihood of notches. Even if force components are high, surface roughness is improved and the risk of fractures is minimized, together with a high evacuation volume. On the other hand, increasing the cutting-edge angle (45° and 60°) without compensating the feed rate, tends to produce tool fractures due to chip overload. Besides, experimental tests showed that long tool-to-workpiece contact times, tend to shorten tool life, due to excessive heat accumulation and poor chip control.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. Funding MCIN/AEI/https://doi.org/10.13039/501100011033 and "FSE invierte en tu futuro", from the Ministry of Science and Innovation of the Government of Spain, in the IB-RELIABLE project (DPI2016-74845-R). UPV/EHU for the financial aid for the pre-doctoral grants PIF 19/96

Roughing Milling with Ceramic Tools in Comparison with Sintered Carbide on Nickel-Based Alloys

Abstract Productivity in the manufacture of aircrafts components, especially engine components, must increase along with more sustainable conditions. Regarding machining, a solution is proposed to increase the cutting speed, but engines are made with very difficult-to-cut alloys. In this work, a comparison between two cutting tool materials, namely (a) cemented carbide and (b) SiAlON ceramics, for milling rough operations in Inconel® 718 in aged condition was carried out. Furthermore, both the influence of coatings in cemented carbide milling tools and the cutting speed in the ceramic tools were analysed. All tools were tested until the end of their useful life. The cost performance ratio was used to compare the productivity of the tested tools. Despite the results showing higher durability of the coated carbide tool, the ceramic tools presented a better behavior in terms of productivity at higher speed. Therefore, ceramic tools should be used for higher productivity demands, while coated carbide tools for low speed-high volume material remova

Estrategias de torneado con aumento del avance en aleaciones base Ni-Co.

231 p.En este trabajo se realiza una investigación experimental acerca de procesos de torneado de alto avance en superaleaciones termorresistentes. Primeramente, se realizaron pruebas de torneado con una herramienta de alto avance para aleaciones termorresistentes y se estudió también el efecto del uso de refrigerante convencional y criogénico. Se crearon modelos mecanísticos para la obtención de coeficientes de corte en Inconel® 718, Nimonic® C-263 y AISI 1055. Los coeficientes de corte se obtuvieron en condiciones de herramienta no desgastada y son útiles para condiciones de corte iniciales, sin embargo, no aportan información sobre el comportamiento del inserto en condiciones de desgaste. A continuación, se evaluó la respuesta al desgaste de los insertos de alto avance al mecanizar Nimonic® C-263 bajo diferentes condiciones. Asimismo, se ha comparado el desempeño de los insertos al mecanizar con taladrina y con CO2. Además, se ha comprobado la efectividad de la disminución del ángulo de posición en la durabilidad del inserto y se ha desarrollado un modelo para la predicción del desgaste. Este modelo considera el deterioro geométrico gradual de la herramienta que se ha demostrado como un mecanismo importante, ya que controla la evolución de las fuerzas de corte en esta superaleación