Monitoring life of diamond tool in ultra-precision machining

摘要

A method has been developed to monitor the tool life through estimating the condition of the tool nose radius without removing the tools during the machining process. This is critical in the single-point diamond turning (SPDT) of precision optical parts like microlens arrays and compound eyes in which complex and free-form profiles are to be generated and in which the tool cannot be reset. Such conditions are determined based on measurement of quasi-circular channels machined by single-pass grooving. For SPDT, when using a new tool, the quasi-circular channels are expected to be reasonably circular when they remain momentarily engaged with the tool. In this paper, a model is proposed to assist in reconstructing the profile of the engaged circular arcs of the channels before re-bouncing. Based on the model, the bottom of the circular arc is flattened and the edges of channel stretched, while the cross-sectional area of the channel remains unchanged even after re-bouncing. Experimental work on SPDT of a 6061 aluminum alloy revealed that these two assumptions hold well at depths of cut between 1 and 1.5 μm.