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Machine Classes – Special Machines

In view of the required piece numbers, the machine classes previously introduced can be manufactured in volume. Specialized machine configurations (for example, two-dimensional machines for measuring profiles and flat parts) can be derived from these lines for restricted applications (see […]

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Machine Classes – Bridge-Type Machines with Air Bearings-2

A fixed-bridge construction is optimally suited to machines with transmitted-light illumination. The rigidity of the entire system enables excellent measuring uncertainty values. This is supported by manufacturing the bridge in a single piece with close tolerances. No subsequent adjustment of […]

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Machine Classes – Bridge-Type Machines with Air Bearings-1

For measuring ranges exceeding roughly 400 mm and where higher accuracy requirements exist, it generally proves economical to use bridge-type machines equipped with air bearings. A fixed-bridge construction is optimally suited to machines with transmitted-light illumination. The rigidity of the […]

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Machine Classes-Precision Machines with Mechanical Bearings-2

Moreover, this guideway system also minimizes friction, reducing backlash on reversal as well. For the same reason, housing covers that produce friction are generally avoided. The long-term stability of the system is further supported by the fact that the guideways […]

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Machine Classes-Precision Machines with Mechanical Bearings-1

In cases where higher demands exist regarding the precision and long-term stability of machines (for example, in the metrology lab and in production control), special new design approaches must be taken. Aluminum is used as a structural material to improve […]

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Machine Classes – Workshop Measuring Machines

One major area of application for coordinate measuring machines is the quality control of manufacturing processes. In order to keep transport routes short, coordinate measuring machines should be installed as close to the production environment as possible. The prevailing environmental […]

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Multisensor Technology

Multisensor coordinate measuring machines use a combination of several of the sensors described above. The properties of these sensors usually depend on their various primary applications (Fig. 27). Regarding applications, their distinguishing characteristics include the size of the object features […]

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Tactile Sensors – Measuring Tactile-Optical Sensor-4

In addition, the principle of self-centering measurement with measuring probing systems is shown here based on the example of the fiber probe (Fig. 25). A calibrated sphere is positioned in a tooth space to determine the pitch errors of a […]

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Tactile Sensors – Measuring Tactile-Optical Sensor-3

If the glass fiber supplies light to the probing tip, measurements can be performed in the self-illuminating mode (Fig. 24). It is also possible to use the fiber probe in the transmitted-light mode. Due to its small dimensions, the resulting […]

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Tactile Sensors – Measuring Tactile-Optical Sensor-2

Fiber probes are manufactured by wire-drawing thin glass fibers and melting the spheres onto them. Good positioning of fiber probes at the location to be measured can be achieved by mounting them in a hollow metal needle (Fig. 23).

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Tactile Sensors – Measuring Tactile-Optical Sensor-1

The conventional mechanical sensors mentioned above all have one thing in common: the signal is transmitted from the probing element through a rigid shaft to the actual sensor (for example, a switch or piezoelectric element). Since each deflection of the […]

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Tactile Sensors – Measuring Tactile Sensors – 2

It is not necessary to remove the stylus from the workpiece in order to measure several different surfaces of the same object. When combined with the appropriate control software, this principle provides the basis for automatic scanning of object surfaces […]

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Tactile Sensors – Measuring Tactile Sensors – 1

In a measuring probing system, the sensor is equipped with path measuring systems (scales, inductive sensors, optical measuring systems, etc.), usually in all three coordinate axes. If, upon contacting the workpiece, the stylus sphere is deflected in any direction, the […]

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Tactile Sensors – Touch Trigger Tactile Sensors

Basic touch trigger probing systems function according to the “three-leg principle” (Fig. 19a). If the stylus sphere contacts the workpiece, a trigger signal is generated for read-out by the scale systems of the coordinate measuring machine. The measured point results […]

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Tactile Sensors

All tactile sensors function on the principle of mechanical contact with the workpiece. The resulting signals are then derived from this contact for further processing. A distinction is made here between touch trigger and measuring probing systems. With a tactile […]

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Multidimensional Distance Sensors

Line sensors (2-D) and area sensors (3-D) function similarly to the spot-shaped distance sensors (1-D) mentioned above. In the laser light section technique (Fig. 16a), the conventional laser triangulation technique is extended to two-dimensional measurement by displacing the laser beam […]

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Laser Point Sensors

The measuring principle of a laser point sensor is based on the projection of a beam of light produced by a laser (usually a laser diode) onto the object to be measured. The reflected beam spot is imaged on an […]

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Autofocus

The same hardware components are used for autofocus as for image processing. When the sensor is moved along the optical axis, a sharply defined image results only in a single position. If the sensor is defocused, blurred images are produced. […]

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Illumination for Visual Sensors – 2

The use of visual sensors usually requires reflected-light as well as transmitted-light illumination. A distinction must be made here between two types: bright field reflected light (Fig. 12b) is projected onto the object parallel to the axis of the beam […]

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Illumination for Visual Sensors – 1

The basis for every optical measurement is to display the features being measured with a highly accentuated contrast. This can best be achieved on the outer edges of objects. In this case, measurement can be performed in transmitted light (Fig. […]

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Visual Sensors – Image Processing Sensor – 3

Today, digitization of images is usually achieved using CCD cameras in conjunction with PC components suitable for image acquisition (framegrabber boards, firewire interfaces, etc.). The chief advantage offered by the CCD camera over the competing CMOS chip lies in its […]

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Visual Sensors – Image Processing Sensor – 2

The lowest measuring uncertainty can b achieved using telecentric lens systems. The advantage of telecentrics is that the lateral magnification remains constant when the working distance is altered within the telecentric range, thus preventing errors of dimension. This is especially […]

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Visual Sensors – Image Processing Sensor – 1

Today, image processing sensors are commonly used as visual sensors (Fig. 8). The object is imaged onto a matrix camera by the lens. The camera electronics convert the optical signal to a digital image, which is then used to calculate […]

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Visual Sensors

The term “visual sensor” denotes all sensors which, similar to the human eye, pick up at least a two-dimensional image of the object being measured. The intensity distribution of this optical image is detected and evaluated by a sensor. For […]

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Sensors for Coordinate Measuring Machines

The sensors of a coordinate measuring machine are used to pick up the primary signal from the workpiece. They are designed using mechanical and, in some cases, opto-electronic and software components of varying complexity. The sensors must be selected on […]

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Bridge-Type Coordinate Measuring Machines

For higher precision requirements and larger measuring ranges, the mechanical guide way of the desktop model is replaced by systems with air bearings.  The high-precision guide ways are typically made of a natural hard stone material like granite.  All moving […]

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Coordinate Measuring Machines with X-Y Stages

The Mechanical components of this group of instruments were created as a logical further development of measuring microscopes and measuring projectors.  They primarily consist of a mechanical stage with mechanical bearings (Fig. 5a).  The Z axis also runs on mechanical […]

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Measuring Microscopes and Projectors – 2

In the case of the profile projector, the instrument’s optics project a correctly scaled image of the workpiece onto a ground glass screen. Using an equally scaled drawing, a direct comparison can be made between the imaged workpiece area and the […]

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Measuring Microscopes and Projectors – 1

The measuring microscope is considered to be the “father” of all coordinate measuring machines. Here, a microscope and the human eye are used as a “sensor” (Fig. 3a). The operator uses a reticle integrated in the beam path to aim at the […]

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Machine Design and Principles of Measurement

Coordinate measuring machines are used to measure geometric features of workpieces such as size, diameter, angle, angularity and parallelism. In principle, relatively complex shape, size and position measurements are reduced to the determination and mathematical evaluation of the spatial coordinates […]

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From Profile Projector to Optical-Tactile Metrology

Up until a few years ago optical (or non-contact) dimensional metrology was dominated by measuring microscopes and projectors which had remained more or less unchanged since the development of the profile projector (below). However, the automatic measurement of geometric features […]

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