Coordinate Measuring Machines and Systems DownloadPDF MB Read online. Since John Bosch edited and published the first version. Why coordinate measuring machine is an exellent investment Money talks; SYSTEMS IS THE BACKBONE TO. PROGRAMME CMM. The article presents the conception of coordinate measurement. The characteristic of two systems (Coordinate Measuring Machine – CMM and.
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Coordinate Measuring Machines (CMMs) are extremely powerful metrological instruments: High unit cost—Because reworking or scrapping is costly, CMM systems significantly bestthing.info References p //. Probe Systems for Coordinate Measuring Machines. Principle of an Electro-Mechanical Switching Probe. Principle of a Measuring Probe with . Results 1 - 20 of [READ ONLINE] Coordinate Measuring Machines and Systems, Second Edition by Robert J. Hocken, Paulo H. Pereira. Book file PDF easily.
Styli for Probes Renishaw offers a comprehensive range of precision-engineered styli for maximum measurement accuracy.
Renishaw will custom build styli to meet your special needs. You supply the thread size, overall length, and ball diameter, Renishaw supplies the rest.
Repair Services Renishaw offers a full range of repair, upgrade and recalibration services for components and systems to ensure ongoing performance and to ensure that you can comply with quality assurance requirements. A range of "Repair by Exchange" RBE units are available for several items as a cost effective repair option and subject to availability we can also offer factory refurbished ML10 lasers and EC10 compensators.
Core Services distributes all products manufactured by Renishaw. Prices may change without notice. Error bars refer to uncertainty stated by the participants.
Table 5: Summary of results obtained from the glass scale measurements. Mean of the Median Standard Nr.
Coordinate Measuring Machines and Systems
The measurements were not thermally compensated in some cases, but, considering the low CLT of the glass, the higher deviations are surely due to bad verification of the CMMs. The mean value of the deviations obtained by all the participants is generally positive, due especially to the deviation of the participants Nr. More significant is the calculation of the median value, which filters possible outliers; in this case the calculated deviations are closer to 0. In this case, the results are generally worst than the measurements on the glass scale, as only 5 participants has obtained an EN value less than 1.
In the measurements of the position of the holes, in fact, more effects contribute to the final results: first of all the geometrical errors of both the coordinate axes, plus the repeatability of the measuring system and the errors due to the alignment. For example, the big deviations obtained by the Participants Nr. Table 6: Summary of results obtained from the Hole Plate measurements.
Mean of the Nr. This comparison confirm what found with the glass scale for most participants Nr. The presence of a squareness error is clearly visible in this case.
Generally, in the evaluation of form errors such as roundness the participants had more difficulties to state the uncertainty; for example, it is possible to notice Table 6, Fig. In Fig. Considering that the nominal value of the length was 32 mm or 16 mm, the results can be compared with the results shown in Fig.
It is possible to notice that in the measurements of the plastic bricks, generally, the results are worse than in the measurements of the glass scale. As the measurements are generally not compensated, a bigger deviation can take place compared with the previous cases. Different results are obtained in the measurement of geometrical features.
Figure 8 shows a summary of results for the measurement of straightness on Plastic Bricks. Similar results are obtained for the measurement of parallelism and perpendicularity between sides of the bricks. A different behavior was found for the measurements of flatness Fig. This is due to the principle of the acquisition of measured points. Planarity, in fact, is generally measured orthogonally to the optical axes and in most cases for video sensors using autofocusing method.
This method is not as accurate and repeatable as the profile detection used for the evaluation of the other measurements, especially for measurement of translucent parts. Deviations from reference values are calculated as the mean value of the absolute values of the deviations of the 4 measured lengths of the bricks sides. Error bars refer to the uncertainty stated by the participants. Deviations from reference values are calculated as the mean value of the absolute values of the straightness deviation for the 4 sides.
A knowledge-based inspection process planning system for coordinate measuring machines
The deviations for the Black Brick The deviation for the Red Brick The effects of optical properties of the object are visible in Fig. The effects of the color are different comparing dimensional and geometrical features. For the measurements of size, the White Brick and Black Brick present a larger dispersion of results, mainly due to their behavior in reflection of light. For the measurement of flatness, the dispersion of the results indicate a higher difficulty in measuring the Red Brick, as most of the video sensors use red lights for autofocusing measurements.
From this figure it is possible to see the influence of the optical properties of the objects Plastic Bricks in this case on the measuring results.
Regarding the estimation of the uncertainty, the increasing complexity of the measuring task has conditioned the results of the participants. Most of the participants 6 participants used the UD method based on the specifications of the manufacturers to state the uncertainty, both for dimensional and geometrical measurements, even if the specifications of the manufacturers are based on dimensional measurements only.
A second phase of the Project has been started in September , involving other countries in Europe. For the comparison, a set of 3 different items has been selected, including both artefacts for performance verification and common industrial workpieces. The audit items have also been chosen in order to be measured with different kind of sensors and to represent a variety of dimensions and geometric quantities.
All the audit items were verified for dimensional stability during the circulation.
A set of detailed measuring procedure was sent together with the artefacts to the participants. The best results were achieved in the measurement of the simplest artefact: the linear glass scale. Air bearings are the chosen method for ensuring friction free travel. In these, compressed air is forced through a series of very small holes in a flat bearing surface to provide a smooth but controlled air cushion on which the CMM can move in a frictionless manner.
The movement of the bridge or gantry along the granite table forms one axis of the XY plane. The bridge of the gantry contains a carriage which traverses between the inside and outside legs and forms the other X or Y horizontal axis. The third axis of movement Z axis is provided by the addition of a vertical quill or spindle which moves up and down through the center of the carriage.
The touch probe forms the sensing device on the end of the quill. The movement of the X, Y and Z axes fully describes the measuring envelope. Optional rotary tables can be used to enhance the approachability of the measuring probe to complicated workpieces. The rotary table as a fourth drive axis does not enhance the measuring dimensions, which remain 3D, but it does provide a degree of flexibility. Some touch probes are themselves powered rotary devices with the probe tip able to swivel vertically through 90 degrees and through a full degree rotation.
As well as the traditional three axis machines as pictured above , CMMs are now also available in a variety of other forms. These include CMM arms that use angular measurements taken at the joints of the arm to calculate the position of the stylus tip. Because CMM arms imitate the flexibility of a human arm they are also often able to reach the insides of complex parts that could not be probed using a standard three axis machine.
Mechanical probe[ edit ] In the early days of coordinate measurement CMM , mechanical probes were fitted into a special holder on the end of the quill.
A very common probe was made by soldering a hard ball to the end of a shaft. This was ideal for measuring a whole range of flat face, cylindrical or spherical surfaces.
Other probes were ground to specific shapes, for example a quadrant, to enable measurement of special features. These probes were physically held against the workpiece with the position in space being read from a 3-Axis digital readout DRO or, in more advanced systems, being logged into a computer by means of a footswitch or similar device.
Measurements taken by this contact method were often unreliable as machines were moved by hand and each machine operator applied different amounts of pressure on the probe or adopted differing techniques for the measurement.Core Services distributes all products manufactured by Renishaw.
Due to the limitation of mechanical probing, the integration of optical sensors into traditional CMMs is getting more and more widespread . All systems have an established reputation for ease of set-up and installation, plus minimal cost of ownership.
Renishaw will custom build styli to meet your special needs. The next generation of scanning, known as noncontact scanning, which includes high speed laser single point triangulation,  laser line scanning,  and white light scanning,  is advancing very quickly. The company's first product, the touch-trigger probe had been invented to solve a specific inspection requirement for the Olympus engines used on the Concorde airplane.
Google Scholar Van't Erve, A. The object of interest is examined by directly viewing the X-rays using an X-ray sensitive vidicon, eliminating the bulky and expensive image intensifier.
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