Sappi has added a new web inspection system to paper mill 2 at its Alfeld site in Hanover, Germany. Sappi has already spent some €61 million in converting the PM2 paper mill in the past year as well as the commissioning of the new Paper Lab a few months ago.
The new inspection system should lead to higher quality as Sappi tries to expand further into the speciality paper sector. It means that even the tiniest of production errors can be detected at machine speeds of up to 1200 m/min across the 4700 mm working width.
The web inspection system is based on camera inspection in transmission and reflection of the web. Sappi has installed three measuring beams on PM2, with the first being located in front of the Speed Coater to check the raw paper. It detects the web using seven transmission cameras. The second beam has been integrated after the last Bladecoater Station on PM2 and uses 12 illumination cameras to detect coating errors in the oblique light by measuring reflection. In this process the camera bar supports are mechanically adjusted and the camera and light angles are aligned with the web in multiple stages. The result is an outstanding scan of the web capable of detecting even the smallest coating errors such as blade marks, coater smudges, scratches or streaks on the functional side of the special paper with a hitherto unknown degree of precision.. The third measuring beam is located in front of the pope reel and uses seven transmission cameras to detect errors in the finished paper.
A high resolution camera delivers photos of the damaged areas and the specific error location is pin-pointed so that the faulty paper location can be cut out to ensure that customers only receive the highest quality. PM2 is used to manufacture special paper types such as Algro Sol, Algro Finess, Algro Vitess, Parade Prima and many other kraft papers.