The availability of sophisticated machine tools, together with advanced cutting tool designs and high performance coatings has allowed machining to meet many challenges. A significant remaining challenge is the competitive milling of hardened steels at moderate to high cutting speeds. This is of particular importance for the die and mould making industry. Despite the necessity to achieve higher production rates and improved surface finish, cutting speeds above the range of 300-600 m/min are still not possible. This limitation is due to the combination of high mechanical, thermal and chemical interactions that are taking place on the tool surface during cutting. To address this situation, an extensive amount of research has been focused on developments associated with hard coatings such as nano-multilayered hard PVD coatings that exhibit novel mechanical and thermal properties. The development of
methodologies for designing a cutting tool with a strong cutting edge micro-geometry has
set guidelines for selecting proper cutting edge preparation for specific cutting applications.
The results indicate that, the development of new hard coating designs is the most effective way to improve the service life of coated carbide tools for hard high speed milling applications. The developments of both robust and rigid substrate designs with adaptive cutting edge micro-geometries assist the cutting tool performance by favoring the surface adaptability of the deposited coating. The developments of different strategies for dry air cooling that provide a "soft-cool" environment seem to have a beneficial impact on cutting performance and tool life improvement. Dry air cooling is found to be more effective than chilled-air cooling and minimum-quantity-lubrication (MQL). Therefore, the utilization of a cutting environment tailored to meet the requirements of both the tool and the coating while providing sufficient air flow to remove chips from the cutting zone will complement the adaptability of the whole tool-workpiece-chip system. / Thesis / Master of Applied Science (MASc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/22305 |
| Date | 08 1900 |
| Creators | Elfizy, Aml |
| Contributors | Veldhuis, Stephen, Mechanical Engineering |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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