UNIT-5 Measuring Machines and Metrology for Nano Measurements Sreekanth N V

Universal Measuring Machine Workpiece is mounted on the UMM Supported on parallels Traverse the machine axes to check for parallelism and flatness Clamp the part Locate the hole using the indicator probe Keep tapping the other side to make the workpiece parallel. Then measure the hole distance and the length to be measured A computer connected will show the profile of the hole and compare with the standard. It is an improvement of length bar measuring machine

Tool Makers Microscope The tool maker’s microscope is a versatile instrument that measure by optical means with no pressure being involved, thus very useful for measurement on small and delicate parts. It is designed for: a) Measurement on parts of complex form e.g. - profile of external thread, tool, templates, gauges, etc. b) Measuring centre to centre distance of holes in any plane. c) A variety of linear measurements. d) Accurate angular measurements.

CMM

CMM Types

Machine Vision Machine vision (MV) is the technology and methods used to provide imaging-based automatic inspection and analysis for such applications as automatic inspection, process control, and robot guidance in industry. The scope of MV is broad. MV is related to, though distinct from, computer vision.

Autocollimator An autocollimator is an optical instrument for non-contact measurement of angles. They are typically used to align components and measure deflections in optical or mechanical systems. An autocollimator works by projecting an image onto a target mirror, and measuring the deflection of the returned image against a scale, either visually or by means of an electronic detector. A visual autocollimator can measure angles as small as 0.5arcsecond (0.15 mrad), while an electronic autocollimator can have up to 100 times more resolution.

Laser Interferometers Interferometry is a family of techniques in which waves,usually electromagnetic, are superimposed in order to extract information about the waves.  Interferometers are widely used in science and industry for the measurement of small displacements, refractive index changes and surface irregularities. Colored and monochromatic fringes in a Michelson interferometer: (a) White light fringes where the two beams differ in the number of phase inversions; (b) White light fringes where the two beams have experienced the same number of phase inversions; (c) Fringe pattern using monochromatic light 

Clean Room Technology Typically used in manufacturing or scientific research, a cleanroom is a controlled environment that has a low level of pollutants such as dust, airborne microbes, aerosol particles, and chemical vapors. To be exact, a cleanroom has a controlled level of contamination that is specified by the number of particles per cubic meter at a specified particle size. The ambient air outside in a typical city environment contains 35,000,000 particles per cubic meter, 0.5 mm and larger in diameter, corresponding to an ISO 9 cleanroom which is at the lowest level of cleanroom standards

Clean Room Standards

Clean Room Standards

Scanning Electron Microscopy A scanning electron microscope (SEM) is a type of electron microscope that produces images of a sample by scanning it with a focused beam of electrons. The electrons interact with atoms in the sample, producing various signals that contain information about the sample's surface topography and composition. The electron beam is generally scanned in a raster scan pattern, and the beam's position is combined with the detected signal to produce an image. SEM can achieve resolution better than 1 nanometer. Specimens can be observed in high vacuum, in low vacuum, in wet conditions (in environmental SEM), and at a wide range of cryogenic or elevated temperatures. Limitations: (a) Live specimen cannot be observed. (b) As the penetration power of electron beam is very low, the object should be ultra-thin. For this, the specimen is dried and cut into ultra-thin sections before observation.

Scanning Electron Microscopy

Transmission Electron Microscopy Transmission electron microscopy (TEM) is a microscopy technique in which a beam of electrons is transmitted through an ultra-thin specimen, interacting with the specimen as it passes through it. Advantages: A Transmission Electron Microscope is an impressive instrument with a number of advantages such as: TEMs offer the most powerful magnification, potentially over one million times or more TEMs have a wide-range of applications and can be utilized in a variety of different scientific, educational and industrial fields TEMs provide information on element and compound structure Images are high-quality and detailed TEMs are able to yield information of surface features, shape, size and structure They are easy to operate with proper training Some limitations of electron microscopes include: TEMs are large and very expensiveLaborious sample preparationPotential\ artifacts from sample preparationOperation and analysis requires special training Samples are limited to those that are electron transparent, able to tolerate the vacuum chamber and small enough to fit in the chamberTEMs require special housing and maintenanceImages are black and white-

Confocal Microscopy Confocal microscopy is an optical imaging technique for increasing optical resolution and contrast of a micrograph by means of adding a spatial pinhole placed at the confocal plane of the lens to eliminate out-of-focus light.

Focused Ion Beam Focused ion beam, also known as FIB, is a technique used particularly in the semiconductor industry,materials science and increasingly in the biological field for site-specific analysis, deposition, and ablation of materials. A FIB setup is a scientific instrument that resembles a scanning electron microscope (SEM). However, while the SEM uses a focused beam of electrons to image the sample in the chamber, a FIB setup uses a focused beam of ions instead. FIB can also be incorporated in a system with both electron and ion beam columns, allowing the same feature to be investigated using either of the beams. FIB should not be confused with using a beam of focused ions for direct write lithography (such as in proton beam writing). These are generally quite different systems where the material is modified by other mechanisms

X Ray Diffraction X-ray powder diffraction (XRD) is a rapid analytical technique primarily used for phase identification of a crystalline material and can provide information on unit cell dimensions. The analyzed material is finely ground, homogenized, and average bulk composition is determined.