DARMSTADT, Germany, June 27, 2013 (Press Release) -The demand for higher quality in tissue products is on the rise. Because of increased competition, there is a need for both increased production speeds and simultaneously for a reduction in sheet breaks. At the Ortmann production facility of SCA Hygiene Products GmbH located in Austria, experts quickly realized that the ability to meet these customer demands would require the use of a fully-automated inspection system. This realization prompted the decision to invest in a Web Inspection System (WIS) from ISRA VISION - a system that provides the ability to identify and categorize quality relevant defects with a high degree of reliability. In addition, a Web Break Monitoring system (WBM) offered by the same manufacturer documents web breaks on the processing line itself. This allows problems in production and processing to become transparent, making it possible to react immediately and therefore to significantly increase production efficiency.
Improving the quality of life - that is what defines SCA Hygiene Products GmbH's corporate vision. The Ortmann plant, which employs a staff of approx. 550, manufactures toilet papers, napkins and other hygienic items. The Web Inspection System (WIS) and the Web Break Monitoring (WBM) from ISRA VISION play a critical role in assuring highest quality products and above average production efficiency.
Identifying every defect at highest resolutions
The WIS monitors the quality of the webs of tissue produced on the PM4 paper machine. The machine produces the thin raw paper at a width of 7 m. At the end of the machine, it is then divided in half lengthwise, and as a result 2 rolls are created with a width of 3.5 m each. The tambour rolls are then wound onto the reel.
"We made the decision to invest in a WIS from ISRA VISION for our hygienic tissue manufacturing", explains Reinhard Höld, production manager in the small roll processing department at SCA Ortmann. "This allows us to increase the production speed of our PM4 paper machine, while maintaining the same level of quality or even improving it." The WIS is able to identify almost every relevant defect at highest resolution even during tissue production on the 7 m wide web at highest production speeds. The state-of-the-art web inspection system makes it possible to reliably detect even the smallest of typical defects, such as holes, folds and spots, at a resolution down to just a few hundred µm with the transmission process. Because it identifies defects immediately, steps can be taken to intervene in the process itself, thereby reducing the number of defective materials being produced.
Seamlessly detecting, categorizing and recording defects
The inspection system consists of highest quality standard components that have been tried and tested. In addition to high power infrared LED technology and the advanced robust software algorithms installed on cutting edge computer technology, the product also features robust camera technology. The technology can be easily integrated into a paper machine's tightest production environment, and supplies reliable results despite dust and heat. Because of the way it is constructed, the system is highly customizable to match the needs of the customer.
The WIS measures, analyzes and categorizes all defective areas automatically and seamlessly. This data is recorded in the tambour report so that processing has the most accurate information in advance with regard to quality and defect distribution, making it possible to choose and treat the tambour accordingly. The defects are also documented in the defect statistics and in the lot report.
Optimized defect recognition and categorization thus ensures that the highest quality demands are met. The causes of defects can be examined in detail. "The ability to categorize defects really helps us in finding ways to optimize the processes", Reinhold Höld emphasizes. The multi-stage classifier ensures highest quality defect classification. A large number of different mathematical characteristics are used to describe defects.
The WIS assists greatly in increasing the production speed of the paper machine and the quality of the tissue products produced. The optimized processes, based on the results supplied by the WIS, significantly improves efficiency.
Preventing web breaks in the processing line
The ability to closely link the inspection system with the web break monitoring system (WBM) increases the benefits even more. Three or four tambours are unreeled in parallel in the downstream processing line, where they are perforated, in part printed and then processed into two, three or four-ply products. In the final step, completely packaged end products then roll off the processing line. Installed at the line's most critical processing steps are the WBM cameras, which focus in particular on the unwinders. The WBM cameras, seven in total and some of which are high-speed units, supply detailed and exactly synchronized images one after the other that allow for a highly efficient cause analysis and the ability to draw conclusions about how defects develop in the system. The entire process chain is monitored and each and every cause of defects is reliably identified. Any remaining breaks are analyzed precisely and the potential causes immediately remedied, if possible.
"We can increase our efficiency even further using WBM, because we can use it to analyze web breaks and therefore significantly reduce their number", explains Reinhard Höld. "This improves our production yield. As an example, we were really surprised to learn that the majority of the breaks in the processing line were caused by defects in the actual paper and only very few were caused in the processing line itself. Now, we really have a much better handle on our processes." With the WBM technology, the number of web breaks was greatly reduced. This really increases the entire system's runability.
Modern inspection systems give the customer the ability to increase value and in effect sustainability by optimizing processes. "We were able to increase the efficiency of the machine as a whole by up to 5%" Reinhard Höld concludes. The web inspection system and the WBM greatly improve the effective capacities of the entire production facility by not only increasing the quality of products, but also the manufacturing efficiency. They ensure that the Ortmann production site, a facility that has been producing paper since 1917, will remain a successful operation for many years to come.