Non-contact optical three dimensional liner metrology

Summary form only given, as follows. We optically captured the "as-built" geometry of NTLX cylindrical liners for Shiva Star using an ultra-precision ranging laser. We subsequently verified the resulting digitized geometry against the 3D CAD model of the part. The results confirmed that the liner contours are within designed tolerances but revealed subtle fabrication artifacts that would typically go undetected. These features included centimeters long waviness and saddle and bulge regions of 1 micron or less in magnitude. The laser technology typically provided 10 micron spatial resolution with 112 nanometer ranging precision. Atlas liners in the future may have to be diamond turned and will have the centimeter wavelength and 100 angstrom amplitude requirements. The advantages of using laser technology is 1) it avoids surface damage that may occur with conventional contact probes and 2) dramatically improves spatial resolution over CMM, LVDT, capacitance and inductance type probes. Our work is the result of a future need to develop precision, non-contact, liner inspection techniques to verify geometry, characterize machining artifacts and map wall thickness on delicate diamond turned surfaces. Capturing "as-built" geometry in a non-contact way coupled with part-to-CAD verification software tools creates a new metrology competency for MST-7.