Construction and testing of a nanomachining instrument

This paper presents a nanomachining instrument that was developed for conducting nanocutting, nanoscratching, and nanoindentation experiments. A piezoelectric tube scanner (PZT) is employed to generate three-dimensional machining motions. The sample is moved by the PZT, and the tool is kept stationary during machining. The machining forces are measured by force sensors with a resolution of sub-milliNewtons. The instrument is compact and can be used inside optical microscopes and scanning electron microscopes. In this paper, depth-sensing indentation experiments were performed to test the basic performance of the instrument. The indentation displacement was measured by a capacitance probe situated inside the PZT tube. An experimental system was constructed to locate and image indentations. The system consists of a high magnification microscope to measure coordinates of the indentation relative to a reference corner point on the sample, and an AFM equipped with an on-axis optical imaging system for locating the indentation. A technique was also employed to establish the tool-sample contact to nanometer accuracy. Indentation experiments were carried out on three kinds of materials with different hardness. Experimental results demonstrated the instrument has the ability of performing depth-sensing indentations. The frame compliance was also evaluated from the indentation results.