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Niploading of SymSizers - problems, corrections and maintenance

Nip loading varies based on the type of size / coating applied, the roll crowns and the incoming sheet. Wrinkles, skewing and e-nip profiles are important.

Hydraulic controls improve performance, reliability - case study

In this case study, Valmet helped a northern USA mill upgrade its hydraulic controls to remove obsolescence, while also improving runnability and reliability.

Pilot trials - a reliable basis for successful business decisions

Mills use Valmet's Technology Centers for a selection of testing and pilot services which help eliminate risks related to business investments and decisions.

Coater backing roll showers - purpose, layout and setup

Showers on the coater backing roll lubricate, cool and prevent coating buildup. This extends roll lifetime and can reduce coater-related sheet breaks.

Start with an audit - common reeling problems and their solutions

Valmet offers reel audits and assessments to help fully understand all aspects of a reeling problem. Discussed here are some common items found when Valmet assesses reel operational challenges.

Instructions for safely taking and using calender nip impressions

Nip impressions are usually taken at installation or to investigate causes for poor paper quality. Taking nip impressions is dangerous if not performed correctly, and should only be done by trained personnel.

The mechanism, need for and effect of reel drum grooving

As machine speed increases and sheet porosity decreases grooving of the reel drum becomes necessary in order to avoid sheet wrinkles, sheet breaks and quality defects.

Doctor and press fabric streaking cause scuff marking, case study

A paper machine with a tri-nip press experienced sheet quality problems with scuff marking after an outage. Two factors contributed - center roll doctor setup and felt cleaning. This case study details the analysis and resolution of the issues.

Winding principles part 1 - TNT overview, effect of web tension

This article is the first in a short series which will explain how web tension, rider roll pressure, and drum torque ratio affect roll quality. Illustrations of key components and control principles will be presented. The series starts with an overview and discussion of web tension.

The 1 Mile Rule analogy of MD length profiles and bagginess

The greater the relative length differences are, the more severe the baggy lanes will be. Proper monitoring tools such as iRoll can help eliminate them.