| Coordinate-measuring Machine |
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Information AboutCoordinate-measuring Machine |
| CATEGORIES ABOUT COORDINATE-MEASURING MACHINE | |
| automation | |
| cnc, cad, and cam | |
| dimensional instruments | |
| production and manufacturing | |
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THE MACHINE ITSELF can be constructed by different kinematic and physical principles. KINEMATIC: First invention UMS 500 (Zeiss/Germany) had solid stand with moving table, succeded by fixed portal (Leitz/Germany). Known are big driving portals (like gantry crane), scara (like the robots; CNC and manual) and others. Manual guided types (low cost) are more and more used as mobile measuring devices. The mechanical probe will be lead into a touching position, before the position is triggert by switch (manual) or the probe itself (CNC). Optional rotary tables can be used to enhance the approachability of complicated workpieces without changing the mechanical probe. The rotary table as forth drive axis does ''not'' enhance the measuring dimensions, which remain 3! PHYSICAL PRINCIPLES: Optical probes and/or laser probes can be used (if possible in combination), which change CMM's to measuring microscopes or multi sensor measuring machines. Fringe projection systems , thodolite triangulation systems or laser distant and triangulation systems are not called measuring machines, but the measuring result is the same: a space point. THE MEASURING PROBE detects the point of beginning material viewing from a chosen direction (-vector), usually perpendicular. MECHANICAL PROBEs touch the material with a hard ball (on the end of a shaft) at the surface with a distinct force. In reaction the probe will be deflected. This deflection can be controlled and measured. The result is the triggering of the "correct" touch point (inside the threshold of precision specification of the manufacturer). OPTICAL PROBEs are lens-CCD-systems, which will be moved like the mechanical ones, but do not touch but take the point of interest to aim. The so showed picture of the surface will be enclosed in the borders of a measuring window, until the residue is adequate to contrast between black and white zones. The dividing curve can be calculated to a point, which is the wanted measuring point in space. The horizontal information on the CCD is 2D (XY) and the vertical position is the position of the complete probing system on the stand Z-drive (or other device component). This allows entire 3D-probing. LASER PROBEs are used to detect the distance between the surface and the reference point on the end of the kinematik chain (i.e.: end of the Z-drive component). This can use an interferometrical, a light deflection or half beam shadowing principle. Modes are single point , scanning or centering. ISO 10360 Performance of CMM German Standard Organization ISO Standards |
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