"Slab track for Transrapid"
M2D laser scanners are controlling precast concrete parts

The situation
For the trackway of the Transrapid, precast concrete parts with maximum accuracy are needed. During concrete production, process-related tolerances of some millimeters arise. To reach the required accuracy of 0,1 mm, the precast parts have to be sized and possibly reworked. With the present, tactile instruments, the complete measuring lasts 15 minutes. In the process, the system achieves only a few measuring points.

The laser measurement is recording over 200 measuring points in less than 2 minutes.

Raw part measurement
Once, without stopping, the system runs over forth and back the pre-fabricated part.
Two M2DF laser scanners are recording at a speed of 15 until 20 m/min. (49 until 65 ft./min.) the entire concrete element. Thereby, all important dimensions are entered and transmitted to CNC control unit.

On the following grinding, the measured data are serving as correction values.

In proof of the required accuracy, a control survey is implemented after grinding .
Double control system      
The system encloses a PLC and a CNC unit. The PLC is responsible for the movement of the system (issuing start and stop signals). For the exact positioning of the axes, for machining and for measurement the CNC is responsible.

Therefore, the MEL sensor technology has to serve two interfaces at the same time.

As online computer a
MEL-i-Control, industrial PC was installed. To PLC, there is a Profibus connection; the time-critical start signals are send to i-Control by the fast digital outputs of the PLC. The CNC gets data by file transfer via Ethernet.
The MEL software is running without mouse and monitor, the operation of the system is fully controlled by CNC. For maintenance and parameter adjustments, it is possible at any time to work with keyboard, mouse and monitor.

Mechanical integration

On grinding process, heavy water vortexes are generated in the environment of the fast rotating grinding disks. Therefore, the laser scanners have been protected with a pneumatically controlled protective lid, including a compressed-air flushing unit.

For over 20 years, MEL is the most innovative producer of intelligent sensors. Take advantage of our experience.
We cope with tasks of automation by using sensor technology and build hard- and software as ideal solution. Alternatively, we deliver modular solutions for integration into OEM projects.