PSP Engineering, one of the best equipped manufacturing companies in the Czech Republic, has been planning and building cement factories, lime works, crushing and screening plants, and processing facilities for coal and ores plant worldwide for more than 50 years. The main products of PSP Engineering are rotary kilns, mills and crushers for cement and mineral processing. In addition, PSP also offers many years of experience and qualified personnel for the manufacture of system components and machines according to customer documentation. The company uses a Tracker3™ laser tracker from Automated Precision Inc. (API) for the measurement of the structures and geometries of its largest workpieces.
Tracker measures the largest components
Prerov, Czech Republic: at peak times, more than 6,000 employees worked in the complex of companies located here, which, at that time, also included a foundry and precision machine construction. The situation has radically changed. Today, PSP Engineering has 400 employees on one part of the site, where the ISO 9001-certified company has taken over and further expanded the production and manufacturing of cement.
At a first glance, it's not obvious that PSP has manufactured the large and heavy parts to the tight tolerances that are part of the customer requirements. In order to guarantee and comply with these (and even tighter) manufacturing tolerances in the future, the management decided to purchase a laser tracker in 2008. The laser-based measurement system, which has not only replaced the former total stations, gages and other equipment in many companies, but has also frequently opened up completely new application areas for laser-based measurement procedures, and is particularly suitable for the measurement of large and difficult to move workpieces with a precision that has been unknown up to now.
After an extensive system comparison, they chose to purchase a Tracker3™ laser tracker from Automated Precision Inc. (API), which was delivered by the German subsidiary, Automated Precision Europe GmbH in Heidelberg. The range of the Tracker3™, which is one of the most compact systems on the market, can be experienced in those industrial areas in which large and complex parts have to be manufactured with high precision - such as in the aerospace and automotive fields and in machine construction, as well as at suppliers to the wind energy sector.
PSP manufactures the large parts, such as cylindrical grinding bowls and the terminal module of drum mills for cement processing, in the aptly-named "super-heavy" hall. Their diameters range from 5.5 m - 10.5 m, with a length of 9 meters - no problem for a laser tracker with an application range several times greater than that. In the drum, which can move in the horizontal plane and be rotated, the balls contained within it grind the material through the rotation of the drum. The drum mills are only assembled on-site, as they can no longer be transported when assembled. The parts are also measured at PSP directly on the production machines, in this case a horizontal lathe.
Diameters, wall thicknesses and radii are mainly measured at PSP using the laser tracker. The fast installation directly in front of the workpiece to be measured and the unlimited portability of the measurement system makes these measurements possible on parts at any location. The tracker head weighs only 8.5 kg with an installation height of 36 cm. In all the measurements at PSP, the laser tracker makes use of its unique capability to also be able to measure large parts quickly, and, above all, with high precision. The laser tracker used at PSP, with an application range of 40 meters, is also suitable for the largest drums and stators; other API laser trackers even achieve measuring distances of up to 60 meters.
SpatialAnalyzer™ software is used with the laser tracker at PSP, and is also responsible for the output of the measurement results in configurable reports. Measurement processes can also be automated in Spatial Analyzer, and the software training for the employees of PSP is provided on-site by API.
Stator construction
The laser tracker also proves its ability to measure oversized parts quickly and effectively when measuring the stators of a large motor that PSP manufactures for many customers. These large components, which are built to customer order, have a dia-meter of as much as 15 meters. Only a very few companies worldwide have the manufacturing know-how for stators of this size, and there are only two companies that can actually build motors of this size. These stators also have to be dismantled into four individual parts for transport, as each of them weighs more than 100 tons. A laser tracker built into the stator checks the compliance with vari- ous tolerances, and, in particular, the position of the large num- ber of sheet metal packages that are inserted, and that consist of plates that are electrically isolated against each other. In the case of stators of the size manufactured by PSP, more than 100,000 plates are laid in the stator. Up to now, measurements have been carried out by means of a column installed at the center point of the stator, which carries a boom in the form of a measuring arm equipped with dial gages, whose radius is 7 meters. The bending of the arm must be particularly taken into account when carrying out measurements. The laser tracker does not have to be mounted at the center point in order to carry out its measurements; based on its measurement principle, the achievable accuracies are higher than those of the measurement results that can be achieved with conventional means. "The measurement results provided by the laser tracker were not directly comparable, and took some getting used to at first," says Libor Janicek, Quality Engineer at PSP. "But, with these measurements, and also thanks to the software that we use and the graphic output options, we obtain new results and insights that we did not have before."
A further application area for the laser tracker at PSP results from the manufacture of pole segments, the counterpart to the stator. They are part of the rotor, the rotating part of the motor. The ex- act compliance with the tight tolerances of the pole segments is a decisive factor for the later efficiency of the motor. Fourteen to twenty-two of these pole segments, which are also constructed from coated plates with integrated coils, are installed in the rotor. Thanks to the portability of the laser tracker, the pole segments can be measured directly on-site. The portable laser measurement system comes to the workpiece, and not vice-versa, which saves time, transport capacity and money. After all, every individual pole segment weighs around 10 tons. Assembled in a few minutes, the laser tracker is ready for use after a short warm-up.
Not only is the laser tracker at PSP in continuous use, but the out- look for the company is also good. At the end of 2010, PSP re- ceived a major contract for building of a new cement factory in Vietnam; engineering, equipment and the technical service for the factory will be provided by PSP.
About PSP Engineering a.s.
PSP Engineering is a leading supplier of specialized equipment and entire plants for the building material and mineral processing industries. For more than 50 years, PSP Engineering has been in- volved in the design and construction of:
• Cement plants and lime works
• Crushing and screening plants for stone, gravel and sand
• Mineral processing plants for coal and ores
PSP Engineering offers advanced solutions in the field of:
• Pyroprocessing
• Grinding, crushing and screening
• Material transport |
