Text

theses

For high productivity, sustainable cutting tools with longer tool life and higher durability, which can withstand high temperature and pressure rises during high cutting speeds, are required in difficult-to-cut machining operations in aerospace, automotive, naval, nuclear and other industries. Currently, cutting coolants and lubricants (lubricoolants) are widely used in industry for thermal and tribological management which provide negative impacts on sustainable environment. The use of lubricoolants has to be reduced or totally eliminated through dry machining, decreasing the environmental hazard and manufacturing cost for improved sustainability. Micro-textured cutting tools can play an important role to achieve this goal. There are several distinct advantages offered by micro-textures applied to cutting tool surfaces to reduce cutting forces, friction, wear and material adherence. However, it is not clear what the optimum pattern and dimensions of these micro-micro-textures should be to obtain minimum forces and wear when using textured cutting tool surfaces in machining processes.
The current work is aimed at investigating the effect of micro-textured insert designs on the cutting forces, but also the effect of micro-groove dimension on the tool wear with experiments. It was expected that the proposed cutting tool surfaces will improve the tribological performance at tool and workpiece interfaces and reduce cutting forces, stresses, and temperatures, and consequently lower usage of energy, coolants, and lubricants in machining of difficult-to-cut materials.
In this research, we investigated the effect of various micro-textured insert designs on the cutting forces and tool wear with experiments in machining titanium alloy Ti-6Al-4V and alloy steel 4340. It was found that micro-texture parameters affect cutting forces and tool wear. Cutting forces are measured by using force dynamometers and the surface topography of the micro-textured tool surfaces were inspected using optical microscopy and focus variation techniques. Micro-texture parameters, groove depth, width, and spacing, are found to be influential on the amount of material smearing into grooves and adhering on the tool surface while reducing thrust forces due to lower contact. Multi-objective optimization studies were conducted to find cutting conditions and micro-groove parameters in machining steel alloy 4340 that minimizes cutting forces and wear. Therefore, the micro-texture design on the tool surfaces can be optimized to obtain lowered cutting forces, improved tool wear, and minimal material adherence. Micro-textured cutting tool parameters as decision variables can be optimized using appropriate optimization strategy that can be obtained from the solution sets. These micro-textures will enable users to practice environmentally sustainable machining through a better application of modern methods such as minimum quantity lubrication, near- dry cutting, cryogenic machining, and solid lubricants.

ETD_9686

M.S.

Includes bibliographical references

doi:10.7282/t3-qsjh-vm08

ETD graduate

The author owns the copyright to this work.