These massive cement drums can easily be measured in a quick setup. The tracker, in its measurements of wall thicknesses and radii, has also been able to share more data with technicians than they had ever received using gauges and wire.
PSP Engineering, one of the largest and most prominent 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 plants worldwide for more than 50 years. The firm produces rotary kilns, mills and crushers for cement and mineral processing. Collectively, PSP’s team boasts decades of experience and numerous qualifications in manufacturing of system components and machines to customer specifications. And to meet its rigorous manufacturing standards, PSP uses a laser tracker from Automated Precision Inc. (API) to measure the structures and geometries of its largest work pieces.
Trackers tackle the biggest measurements
PSP is locatd in Prerov, Czech Republic, a city that at one time was a manufacturing capital, with more than 6,000 employees working in the complex of companies in this city, which also included a foundry and precision machine construction. Today, PSP Engineering a.s. has 400 employees on one part of the site, where the ISO 9001-certified company has taken over and, over the years, developed its industry-leading expertise in manufacturing and cement production. PSP’s customer service commitment is to manufacture large and heavy parts to the rigorous tolerances that the customer requires. In order to be able to continue to guarantee and comply with increasingly stringent manufacturing tolerances, the management decided to purchase a laser tracker in 2008. The laser-based measurement system has since replaced the former total stations, gauges and other equipment in many companies. It also frequently finds completely new applications for laser-based measurement procedures and is particularly suitable for the measurement of massive, cumbersome work pieces with unprecedented accuracy.
After an extensive system comparison, PSP’s leaders decided to purchase a laser tracker from Automated Precision Inc. (API), which was delivered by its German subsidiary, Automated Precision Europe GmbH of Heidelberg. As one of the most compact measuring systems on the market, API’s trackers have proven
themselves to be essential in a range of industries, where large and complex parts must be manufactured to exact standards. This includes the aerospace and automotive fields, machine construction, as well as the suppliers of wind energy turbines and other areas of alternative energy.
PSP manufactures the large parts, such as cylindrical grinding bowls and the terminal module of drum mills for cement processing, in its so-called “super-heavy” hall. Their diameters range from 5.5 meters to 10.5 meters, and can be as long as 9 meters. But this poses no problem for a laser tracker, which can measure much larger dimensions than this. In the drum, which can move horizontally and rotate, the balls contained within it grind the material through the rotation of the drum. The drum mills are only assembled on site, as they cannot be transported once assembled. The parts are also measured at PSP directly on the production machines, in this case a horizontal lathe.
The laser tracker at PSP is mostly used to measure work piece diameters, wall thicknesses and radii. The tracker can be quicky set up directly in front of the work piece to be measured. Its compact features (8.5 kg head and an installation height of 36 cm) makes it easy to take these measurements at any location. For any measurement, the API tracker offers a quick and easy set-up and highly precise readings. The laser tracker used at PSP, with an application range of 40 meters, is also suitable for the largest drums and stators; other API trackers even achieve measuring distances of up to 60 meters.
API trackers process data on Spatial Analyzer software, which is reinstalled on the tracker. SA produces 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.
PSP’s laser tracker also proves its versatility when it is used on the stators of a large motor that the firm manufactures for many of its customers. These large components, which are built to order, have a diameter of up to 15 meters. Few companies worldwide have the manufacturing know-how for stators of this size, and there are only two companies that can build them. 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 at various tolerances, and is used to pay particular attention to the position of the large number of sheet metal packages inserted. Each of them contain 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 gauges with a radius of 7 metres. The bending of the arm requires especially close attention when carrying out measurements. But 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.”
The laser tracker at PSP is also used to build pole segments, the counterpart to the stator. They are part of the rotor, the rotating part of the motor. The exact compliance with the tight tolerances of the pole segments is a decisive factor for the later efficiency of the motor. Fourteen to 22 of these pole segments, which are also made from coated plates with integrated coils, are installed into the rotor. Thanks to the portability of the tracker, the pole segments can be measured directly on site. The portable laser measurement system comes to the work piece — 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 phase.
The laser tracker remains in continuous use at PSP and the outlook for the company is good: at the end of 2010, PSP received 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.
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