Measurement of Tool Temperature Using Thermal Imaging in Interrupted Cut Turning

The creation of oscillating tool paths for turning operations that use the numerically controlled machine axes to ensure reliable chip breaking has been demonstrated in a variety of materials. The interrupted cuts created in this way have the additional benefit of allowing the temperature of the tool-chip interface to be controlled at a significantly lower level than in conventional turning. In traditional continuous turning, the interface temperature rises to a high level and stays there during machining. This is especially a problem for difficult-to-machine materials, because many tool wear mechanisms are strongly temperature dependent. In the chip breaking tool paths, the axes of the machine are used to oscillate the tool along the programmed tool path and before the temperature has a chance to rise to damaging levels, the cut can be interrupted so that the tool can cool. This is analogous to the technique of using shallow radial depths of cut in milling operations for difficult-to-machine materials. In this work, a thermal imaging camera is used to verify that this strategy can be effective in the machining of steel. The results from the thermal imaging studies show that over a broad range of conditions, oscillating tools paths create lower temperatures at the tool-chip interface.