Investigation of 3D Non-Contact Laser-Based Inspection Techniques for Application in Gear Metrology

Gear shape accuracy, surface quality and, as a consequence, a proper gear inspection needed to guarantee these features, are critical in order to improve drivetrain efficiency as well as to reduce noise in automotive power transmission systems. Contact stylus type measuring methods using contact probes are today’s dominant indus- trial solution for gear metrology. Due to the difficulties of further improving those methods, new non-contact measuring systems have been developed in the past few years. The most promising option that meets the requirements of accuracy, repeatability and high cycle time is the 3D non-contact measurement method based on triangulation laser sensors. These laser scanners have been improved over the last few years both in terms of resolu- tion, optical quality, image processing and data analysis to make them comparable, if not superior, to the traditional contact probe. This thesis provides an evaluation of the surface profilometer Urano HC-N400, using the contact technology currently employed by Omega gear metrology labs as a benchmark. The measurements obtained with the alternative inspection system indicate that the analyzed non-contact solution is not ready yet for in-line and high volume inspection applications, but is well-suited to research and development purposes. Omega is also looking for the possible causes of a particular noise problem which is difficult to detect using current technology. One gear that exhibited this phantom phenomenon, also know as the ghost noise , has been analyzed and compared with another gear identified as the best of best . During the analysis, undulations have been found in both gears. The combination of those waves through the use of the Ripple Analysis software represents the best solution to discover other gears with the same problem in the early stages of inspection

Calibrating evanescent-wave penetration depths for biological TIRF microscopy

Roughly half of a cells proteins are located at or near the plasma membrane. In this restricted space the cell senses its environment, signals to its neighbors and ex-changes cargo through exo- and endocytotic mechanisms. Ligands bind to receptors, ions flow across channel pores, and transmitters and metabolites are transported against con-centration gradients. Receptors, ion channels, pumps and transporters are the molecular substrates of these biological processes and they constitute important targets for drug discovery. Total internal reflection fluorescence microscopy suppresses background from cell deeper layers and provides contrast for selectively imaging dynamic processes near the basal membrane of live-cells. The optical sectioning of total internal reflection fluorescence is based on the excitation confinement of the evanescent wave generated at the glass-cell interface. How deep the excitation light actually penetrates the sample is difficult to know, making the quantitative interpretation of total internal reflection fluorescence data problematic. Nevertheless, many applications like super-resolution microscopy, colocalization, fluorescence recovery after photobleaching, near-membrane fluorescence recovery after photobleaching, uncaging or photo-activation-switching, as well as single-particle tracking require the quantitative interpretation of evanescent-wave excited images. Here, we review existing techniques for characterizing evanescent fields and we provide a roadmap for comparing total internal reflection fluorescence data across images, experiments, and laboratories.Comment: 18 text pages, 7 figures and one supplemental figur

Sub-lunar Tap-Yielding eXplorer, STYX

To diversify the idea pool that NASA has to draw from for future manned and unmanned missions to the Moon and Mars, a design/build competition has been posed to collegiate teams across the country. The challenge is to reach, extract, and purify underground ice reserves in a setting analogous to mars. Along the way, teams will be collecting telemetry to mimic prospecting objectives on the moon. The Sublunar Tap-Yielding eXplorer, STYX, is the team’s proposed design for the 2020 NASA RASC-AL competition. Some novel design features STYX will use are a rotary tool changer with swappable tools, a sleeve driving mode, and a pivoting heating probe. The STYX drill head will translate on two axes, use a rotary hammer drill to bore holes, sleeve boreholes with pipe to prevent collapse, and deliver water via a peristaltic pump and a two stage filtration system. Several of these design elements are innovative and conceptually proven through preliminary testing. These efforts are expected to net increased performance and differentiate STYX from other prototype submissions

Integration of an isotropic microprobe and a microenvironment into a conventional CMM

This paper describes the experimental verification of the novel IMT-PTB microprobe combined with a uniquely designed microenvironment. The microprobe consists of three silicon-based parallelograms stacked orthogonally, which leads to high isotropy. The probe tip deflections are detected in 3D with the help of piezoresistors placed in the parallelograms. The microenvironment facilitates and improves the measurement of workpieces with submillimeter features. The new microprobe and the microenvironment were integrated into a commercial coordinate measuring machine (CMM). To evaluate the microprobe performance, PTB produced and calibrated three reference objects: a cube, a sphere, and a microgear measurement standard. The differences between the calibration values and the measurement results obtained by the microprobe were in the sub-micrometer range. Furthermore, the microprobe was compared with the standard probing system of the gear measuring machine by measuring the reference objects with identical parameters. The results show the excellent performance of the micro probing system, thereby extending the capability of the CMM for high-precision measurements of complex workpieces at the microscale

Feasibility Study of Infrared Detection of Defects in Green-State and Sintered PM Compacts

The electric Joule heating of solid materials through direct current excitation can be used to generate a temperature profile throughout a powdermetallic (P/M) compact. When recording the surface temperature distribution with an infrared (IR) camera important information regarding the integrity of the sample can be gained. This research will concentrate on the formulation of a mathematical model capable of predicting the temperature distribution and heat flow behavior in P/M parts and its relations to the supplied current, injection method, geometric shape as well as the thermo-physical properties. This theoretical model will subsequently be employed as a tool to aid in the actual measurements of infrared signatures over the sample surface and their correlation with the detection of surface and subsurface flaws. In this work we will develop the theoretical background of IR testing of green-state and sintered P/M compacts in terms of stating the governing equations and boundary conditions, followed by devising analytical and numerical solutions. Our main emphasis is placed on modeling various flaw sizes and orientations in an effort to determine flaw resolution limits as a function of minimally detectable temperature distributions. Preliminary measurements with controlled and industrial samples have shown that this IR testing methodology can successfully be employed to test both green-state and sintered P/M compacts

Far-infrared polarimetry from the Stratospheric Observatory for Infrared Astronomy

Multi-wavelength imaging polarimetry at far-infrared wavelengths has proven to be an excellent tool for studying the physical properties of dust, molecular clouds, and magnetic fields in the interstellar medium. Although these wavelengths are only observable from airborne or space-based platforms, no first-generation instrument for the Stratospheric Observatory for Infrared Astronomy (SOFIA) is presently designed with polarimetric capabilities. We study several options for upgrading the High-resolution Airborne Wideband Camera (HAWC) to a sensitive FIR polarimeter. HAWC is a 12 x 32 pixel bolometer camera designed to cover the 53 - 215 micron spectral range in 4 colors, all at diffraction-limited resolution (5 - 21 arcsec). Upgrade options include: (1) an external set of optics which modulates the polarization state of the incoming radiation before entering the cryostat window; (2) internal polarizing optics; and (3) a replacement of the current detector array with two state-of-the-art superconducting bolometer arrays, an upgrade of the HAWC camera as well as polarimeter. We discuss a range of science studies which will be possible with these upgrades including magnetic fields in star-forming regions and galaxies and the wavelength-dependence of polarization.Comment: 12 pages, 5 figure

Micro/Nano Manufacturing

Micro- and nano-scale manufacturing has been the subject of ever more research and industrial focus over the past 10 years. Traditional lithography-based technology forms the basis of micro-electro-mechanical systems (MEMS) manufacturing, but also precision manufacturing technologies have been developed to cover micro-scale dimensions and accuracies. Furthermore, these fundamentally different technology platforms are currently combined in order to exploit the strengths of both platforms. One example is the use of lithography-based technologies to establish nanostructures that are subsequently transferred to 3D geometries via injection molding. Manufacturing processes at the micro-scale are the key-enabling technologies to bridge the gap between the nano- and the macro-worlds to increase the accuracy of micro/nano-precision production technologies, and to integrate different dimensional scales in mass-manufacturing processes. Accordingly, this Special Issue seeks to showcase research papers, short communications, and review articles that focus on novel methodological developments in micro- and nano-scale manufacturing, i.e., on novel process chains including process optimization, quality assurance approaches and metrology