Tool makers microscope

Measuring principle

The work piece to be checked is arranged in the path of the rays of the lighting equipment.

It produces a shadow image, which is viewed with the microscope eyepiece having either a suitable mark for aiming at the next points of the objects or in case of often occurring profiles. e.g. Threads or rounding – standard line pattern for comparison with the shadow image of the text object is projected to a ground glass screen.

The text object is shifted or turned on the measuring in addition to the comparison of shapes.

The addition to this method (shadow image method), measuring operations are also possible by use of the axial reaction method, which can be recommended especially for thread measuring.

This involves approached measuring knife edges and measurement in axial section of thread according to definition.

This method permits higher precision than shadow image method for special measuring operations.

ApplicationsThe large tool maker’s microscope is suitable for the following fields of applications;

•Length measurement in cartesian and polar co-ordinates.

•Angle measurements of tools; threading tools punches and gauges, templates etc.

•Thread measurements i.e., profile major and minor diameters, height of lead, thread angle, profile position with respect to the thread axis and the shape of thread. (rounding, flattering, straightness of flanks)

•Comparison between centres and drawn patterns and drawing of projected profiles.

• Examination of form tools, plate and template gauges, punches and dies, annular grooved and threaded hobs etc.

• Measurement of glass graticules and other surface marked parts.

• Elements of external thread forms of screw plug gauges, taps, worms and similar components.

• Shallow bores and recesses.

Profile Projector

An Profile Projector (often simply called a optical comparator in context) is a device that applies the principles of optics to the inspection of manufactured parts.

In a comparator, the magnified silhouette of a part is projected upon the screen, and the dimensions and geometry of the part are measured against prescribed limits.

Profile Projector Applications

intended for the routine inspection of machined parts, was a natural next step in the era during which applied science became widely integrated into industrial production.

It’s also employed for inspecting and comparing very small and complex parts, which play very significant role in system’s structure, as an application of quality.

Profile Projector Advantages

• Profile Projector can reveal imperfections such as burrs, scratches, indentations or undesirable chamfers which both micrometers or calipers can’t reveal.

• They’re able to measure in 2-D space. Unlike micrometers and calipers, which measure one dimension at a time, where comparators measure length and width simultaneously.

• Cost savings:

• Optical comparators save time. Ease-of-use factors and ergonomic designs reduce the inspection time, retraining costs and operator fatigue, all while increasing throughput.

• Custom hard gages are subject to wear and need frequent recertification, which takes them out of service and adds an additional cost.

Profile Projector Disadvantage

The limitation of using profile projector as a fixed device forms a disadvantage of it, while instruments such micrometer or calipers can be used to reach for measuring far and joint accessible components and it is large and bulky and usually require a cart to transport from place to place, also the device requires power for operation.

Optical microscope

Scanning Electron Microscope

The scanning electron microscope (SEM) uses a focused beam of high-energy electrons to generate a variety of signals at the surface of solid specimens.

The signals that derive from electron-sample interactions reveal information about the sample including external morphology (texture), chemical composition, and crystalline structure and orientation of materials making up the sample.

In most applications, data are collected over a selected area of the surface of the sample, and a 2-dimensional image is generated that displays spatial variations in these properties. Areas ranging from approximately 1 cm to 5 microns in width can be imaged in a scanning mode using conventional

SEM techniques (magnification ranging from 20X to approximately 30,000X, spatial resolution of 50 to 100 nm). The SEM is also capable of performing analyses of selected point locations on the sample; this approach is especially useful in qualitatively or semi-quantitatively determining chemical compositions (using EDS), crystalline structure, and crystal orientations (using EBSD). The design and function of the SEM is very similar to the EPMA and considerable overlap in capabilities exists between the two instruments.

Applications• In addition to topographical, morphological and

compositional information, a Scanning Electron Microscope can detect and analyze surface fractures, provide information in microstructures, examine surface contaminations, reveal spatial variations in chemical compositions, provide qualitative chemical analyses and identify crystalline structures.

• SEMs can be as essential research tool in fields such as life science, biology, gemology, medical and forensic science, metallurgy.

• In addition, SEMs have practical industrial and technological applications such as semiconductor inspection, production line of miniscule products and assembly of microchips for computers.

SEM Advantages

Advantages of a Scanning Electron Microscope include its wide-array of applications, the detailed three-dimensional and topographical imaging and the versatile information garnered from different detectors.

SEMs are also easy to operate with the proper training and advances in computer technology and associated software make operation user-friendly.

This instrument works fast, often completing SEI, BSE and EDS analyses in less than five minutes. In addition, the technological advances in modern SEMs allow for the generation of data in digital form.

Although all samples must be prepared before placed in the vacuum chamber, most SEM samples require minimal preparation actions.

SEM Disadvantages

•The disadvantages of a Scanning Electron Microscope start with the size and cost.•SEMs are expensive, large and must be housed in an area free of any possible electric, magnetic or vibration interference.•Maintenance involves keeping a steady voltage, currents to electromagnetic coils and circulation of cool water.•Special training is required to operate an SEM as well as prepare samples.•The preparation of samples can result in artifacts. The negative impact can be minimized with knowledgeable experience researchers being able to identify artifacts from actual data as well as preparation skill. There is no absolute way to eliminate or identify all potential artifacts.•In addition, SEMs are limited to solid, inorganic samples small enough to fit inside the vacuum chamber that can handle moderate vacuum pressure.•Finally, SEMs carry a small risk of radiation exposure associated with the electrons that scatter from beneath the sample surface.

Transmission electron microscope

The transmission electron microscope (TEM) operates on the same basic principles as the light microscope but uses electrons instead of light. What you can see with a light microscope is limited by the wavelength of light. TEMs use electrons as "light source" and their much lower wavelength makes it possible to get a resolution a thousand times better than with a light microscope.

You can see objects to the order of a few angstrom (10-10 m).

Transmission electron microscopy (TEM) is a microscopy technique whereby a beam of electrons is transmitted through an ultra-thin specimen, interacting with the specimen as it passes through. An image is formed from the interaction of the electrons transmitted through the specimen; the image is magnified and focused onto an imaging device, such as a fluorescent screen, on a layer of photographic film, or to be detected by a sensor such as a CCD camera.

TEM Applications•A Transmission Electron Microscope is ideal for a number of different fields such as life sciences, nanotechnology, medical, biological and material research, forensic analysis, gemology and metallurgy as well as industry and education.

•TEMs provide topographical, morphological, compositional and crystalline information.

•The images allow researchers to view samples on a molecular level, making it possible to analyze structure and texture.

•This information is useful in the study of crystals and metals, but also has industrial applications.

•TEMs can be used in semiconductor analysis and production and the manufacturing of computer and silicon chips.

• Technology companies use TEMs to identify flaws, fractures and damages to micro-sized objects; this data can help fix problems and/or help to make a more durable, efficient product.

• Colleges and universities can utilize TEMs for research and studies.

• Although electron microscopes require specialized training, students can assist professors and learn TEM techniques.

• Students will have the opportunity to observe a nano-sized world in incredible depth and detail.

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

Disadvantages•TEMs are large and very expensive•Laborious sample preparation•Potential artifacts from sample preparation•Operation 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 chamber•TEMs require special housing and maintenance•Images are black and white•Electron microscopes are sensitive to vibration and electromagnetic fields and must be housed in an area that isolates them from possible exposure.•A Transmission Electron Microscope requires constant upkeep including maintaining voltage, currents to the electromagnetic coils and cooling water.

Straight edge

Straight edge is a measuring tool which consists of a length of steel or other suitable material usually of narrow and deep section and vary in length from several millimeters to a few meters.

The object of the deep and narrow section is to provide considerable resistance to bending in the plane of measurement without excessive weight

The accuracy of the straight edge should be high and permissible deviation of the measuring edge from the true straight line should not exceed

+ (0.001+ L/500000)mm

Surface plate

• A surface plate is a solid, flat plate used as the main horizontal reference plane for precision inspection, marking out (layout), and tooling setup.

• The surface plate is often used as the baseline for all measurements to the workpiece, therefore one primary surface is finished extremely flat with accuracy up to 0.00001 in/0.00025 mm for a grade AA or AAA plate. Surface plates are a very common tool in the manufacturing industry and are often permanently attached to robotic type inspection devices such as a coordinate-measuring machine.