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In Focus - Archive November 2009
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01.11.2009 -
In addition to a high repeat accuracy, in modern machine tools, positioning-, measuring- and handling the accuracy of the axial movement is now playing an important role. In this way, precise parts for the production or electronic industry, can be designed with a micron-precise guidance along the complete axis. Laser measuring can be used for assembly and control of such systems, and also for trouble-shooting after a crash. Laser measuring recognizes smallest errors in movement and supplies the decisive background for their corrections.
Laser measuring is used everywhere, whether a user has to rely on a high process accuracy of linear motions or on a high absolute accuracy during manufacturing and control processes. Normally, tolerances below 0.005 mm during the complete motion are focus. Modern precision measuring systems, so-called laser interferometers, determine the data.
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Here micron precision is concerned: With laser measuring SCHUNK determines the precision of the linear system.
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Here micron precision is concerned: With laser measuring SCHUNK determines the precision of the linear system.
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Achieving the goal with precise modules and modern measuring technology
Laser measuring technology is packed with know-how: Bundled light is directed via beam splitters and mirrors onto separated optical paths. At the end of the measuring path it is reflected via mirrors and then it is merged again in the measuring unit [compare the chart of the laser principle]. The difference of the light ray results in a specific pattern, the so-called interference fringe or -ring, from which the distances, angular deviations and refraction index are determined. Laser interferometers are used for research- and laboratory applications. They are also used for quality management and are even used directly from the users on site.
In order to determine the positioning and process accuracy of linear systems, the laser interferometer is adjusted parallel to the controlled axis. The optical paths are separated into a measuring ray and a reference ray. A measuring unit superimposes the reflected in-phase and wave fronts with the same frequency and issues them as a measuring size. Software finally prepares the reversal error, range, guidance, or position deviation graphically.
The basis for determining the positioning accuracy generally are the criterions of approval according to VDI/DGQ 3441, for straightness measurement the criterions according to VDI/DGQ 2617. New directives are also defined in the DIN ISO 230-2. Since the data received of the measurement are often compared with other data, the evaluation according to the VDI rules are considered to be the most important ones.
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The laser interferometer can recognize the smallest deviations, thanks to light waves.
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From the measuring results, the straightness of a guiding axis can be read out, too.
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Deviations are corrected mechanically, or in the control unit
Concerning the guidance accuracy of linear systems, particularly the angular error, pitch and yawing angle and the resulting rotation of a guidance are of interest. Latest laser interferometers also provide dynamic values such as path-time, speed-time and acceleration-time graphics. If the systems are used in highly dynamic applications, these values play an important role.
Based on the deviations, measured systems can be easily corrected. This is done mechanically by aligning the assembly groups and components to each other. Moreover, in a so-called mapping, systematic deviations such as reversal error or deviations in position are compensated via an error chart in the machine’s control unit.
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Precise measuring results are profitable
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By means of laser measuring an extremely high precision during the complete motion process is ensured. This is the precondition for precise machining and controlling processes and has further benefits:
- The precise alignment of the system’s components minimizes wear and assures a long service lifetime of the whole system.
- Laser measuring provides the basis for documentation and quality management and it strengthens the competence of plant constructors and system integrators.
- It simplifies trouble-shooting and saves time in case of problems with an existing plant after a crash.
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SCHUNK offers laser measuring as an extra service
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As a leading expert in automation, SCHUNK offers a vast program of standard modules and individual assembly groups, along with the new service of laser measuring. This enables plant constructors and system integrators to ensure and document that their supplied systems measure up to all the requirements.
- Based on the measuring results you can optimize your system, improving process reliability and an increased lifetime.
- You are receiving informative protocols on the accuracies of your systems which can be integrated in the documentation.
- In case of complaints the measuring results can be used as a practical assistance.
With mobile laser interferometers, SCHUNK measures the systems directly on-site. The experts of the service team determine among other things the position, the tilt angle as well as the straightness of the linear system. Moreover, dynamic measurements of the plant are carried out. After measurement SCHUNK then evaluates together with the user, the system integrator or plant constructor the results. Laser measurement can be used for SCHUNK products, and also for existing plants with components of other users.
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This new measuring service is currently only available in Europe.
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11.2009
Straightaway micron-precise
In addition to a high repeat accuracy, in modern machine tools, positioning-, measuring- and handling the accuracy of the axial movement is now playing an important role. In this way, precise parts for the production or electronic industry, can be designed with a micron-precise guidance along the complete axis.
 more...
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10.2009
How Machines Can Learn To See
More and more industries tap the full potential of machine vision systems. Whether in the supermarket, on the highway, at the airport, or in the factory; pictures are being taken by a camera system and are evaluated with a computer, in order to make a fully-automatic, quick and safe decision.
more...
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09.2009
Hydraulic expansion technology for workpiece clamping
Hydraulic expansion toolholders for tool clamping (milling cutter, drills, taps and reamers) are known on the market for a long time and are appreciated for their technical advantages. They combine powerful, centric clamping with a high internal dampening. The result is an excellent surface at high machining speeds.
more...
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08.2009
Gripping - checking - measuring - preventing from damage
Intelligent sensors transform actuators to sensitive helpers in automation
Sensors used in automation are essential organs of machines and plants. While gripping modules and other actuators performed pre-defined tasks in the past, today, they are intelligent and flexible helpers in the manufacturing process due to the use of intelligent sensors. They provide the plant with important information on the process, products or components as well as plant functions. This increases flexibility, shortens manufacturing time, ensures product quality, avoids plant failures, and prevents the automation systems from damage.
more...
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07.2009
The trend towards precision toolholders
For many years, collet chucks have been popular because of their low pricing and have been the established toolholders for many machining applications. Unfortunately, the same scenario happens in many companies: Because of worry over loose tools, many machine operators are tightening the coolant tube nut of the collet mountings with oversized extensions.
more...
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06.2009
Always up-to-date with the standards - The new machinery directive in the EC
The safety of products and systems traditionally tops the priority list at SCHUNK. Since we want to partner with our customers, we are exclusively offering top-of-the-line products in quality and safety.
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05.2009
Highly economical due to performance in toolholding and workholding
5-axis machines offer an enormous potential for efficiency in modern production. With sturdy machine kinematics, high axis accelerations, short chip-to-chip times, fast tool magazines and finely tuned controllers, you have all kinds of production power in a very small space.
more...
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04.2009
Microvalve Technology
- Small component handling and assembly
Anyone who wants to handle or assemble small, light parts can really get a move on with electromagnetic microvalves. These energy-efficient valves are screwed directly onto the pneumatic actuator and thus eliminate the need for long wires. They make the tempo significantly faster and thus save compressed air, complicated wiring, and a lot of assembly time.
more...
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03.2009
Reliable precision for the most well-hidden corners
Regardless of their design sophistication, it is sometimes impossible to avoid cre-ating hard-to-reach points on workpieces. All of these cases require slim toolholder systems with minimized interference contours. They have to penetrate into the most well-hidden corners, transmit sufficient torque and guarantee high precision at the same time.
more...
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02.2009
The foundry sector: a red-hot key industry
With 87,000 employees and sales of around €14 billion in 2007, the foundry sector is one of German industry's smaller branches. Its economic significance is large.
more...
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In Focus - 2010
In Focus - Archive 2009
In Focus - Archive 2008
In Focus - Archive 2007
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