No abstract

The sintering temperature and holding time have a significant impact on the densification of a ceramic compact. In this study, alumina inserts were made with varying sintering temperatures and holding times. The procedure began with the compacting of alumina powders inside a mould with trapezium and round shapes. These inserts were then sintered between 1200 °C and 1400 °C for 5 to 9 h holding time. The sintered samples underwent analysis based on the shrinkage size, density, and microstructure. The sample with the highest density was chosen for additional machining tests. The results showed that the alumina shrinkage ranged from 3 to 6%, with a maximum relative density of 91.3% recorded when the sintering parameter was applied at 1400 °C and a 9 h holding time. The transition of the grain growth was observed depending on the sintering temperature and heating duration. When machined with AISI 1045 carbon steel, the sintered alumina inserts achieved a maximum tool life of 35 s at a cutting speed of 350 m/min. The sintered inserts exhibited brittle characteristics with a dominant notch wear and abrasive mechanisms.

High Thermal Conductivity Steel-150 (HTC-150) is a specific steel designed for use in the hot stamping process as a stamping die. HTCS-150 die steel was difficult to machine due to its high strength, hardened state, and high thermal conductivity characteristics, which necessitated parameter control for a fine surface finish and maximum tool life. The characteristics of tool wear when machining HTCS-150 hardened steel (52 HRC) with a ball nose end mill TiAlN coated carbide insert is presented in this study. Cutting speed, feed rate, and axial depth of cut have all been varied in machining trials. Response surface methodology experimental design was used to create a parametric optimisation model. The results indicate that the model develops an accurate prediction, with comparisons between measured and expected results suggesting that the model operates within the 90% prediction interval with an error of less than 10%. The lowest tool wear was achieved at 130 m min−1 cutting speed, 0.4 mm/tooth feed rate, and 0.1 mm axial depth of cut, according to the optimisation results. The most influenced cutting parameters were found to be feed rate and depth of cut, followed by cutting speed. The wear surface texture analysis revealed coating delamination, adhesion, built-up edge formation, and tool edge chipping. The findings of this experimental study can be used to machine the HTCS-150 for the longest possible tool life while maintaining a fine surface finish.

No abstract

No abstract