Up and Running articles
Up and Running articles
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Field Report - Slitter blade and band sharpening
Slitters must be sharp and properly sharpened. The best way to maintain a continual supply of sharp slitter blades is to use the Valmet BladePool service. If, however, you choose to do your own sharpening, here are some general instructions for sharpening at the mill.
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Field Report - Spreader roll problems, solutions and services
Spreaders deal with web instability, using the principles of tension and traction to overcome dishing and interweaving. Valmet spreader roll services ensure spreading efficiency with all-round cost control.
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Field Report - Felt roll safety
When lifting, operating and servicing the rolls, obey the OEM and mill safety instructions regarding lifting points, nips, lifting instruments and guards in order to maximize occupational safety.
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Field Report - Blade-type doctors, design and operation
Doctors are used to scrape foreign material off rolls or to redirect the web to prevent wrapping around rolls. Doctor components vary, but all blade type doctors will have blade(s), blade holder(s) and beam. Heaters, oscillators, air blows and catch pans are common additional options.
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Field Report - General reel service and adjustments
Many reel service actions and adjustments are common to all paper machine reels. This article reviews on-the-run (OTR) monitoring of the reel, as well as long-term (20 year) checks such as screw torques and critical seam weldments. Consumables must be inspected and replaced as needed, especially actuators and cylinder seals.
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Field Report - Understanding coater blade angle vs. loading tube pressure
For a given blade tip bevel, when load tube pressure is increased, the blade angle will decrease, resulting in the blade running on its heel for a while. This, along with the additional bending pressure at the blade tip, will reduce coat weight. It is important to understand the interaction between blade angle, blade tip angle and loading tube pressure.
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Field Report - Coater blade angle measurement and interpretation
Measuring and interpreting coater blade wear angle can avoid problems such as scratching, poor coat weight appearance, wet bleeding and weeping at the blade tip. Correct positioning of the blade on its bevel will optimize sheet smoothness.
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Field Report - Size press roll wear, a case study
A P&W paper machine suffered from excess wear on the back edge of the bottom size press roll. The problem was traced to the size press synchronization shaft. When the shaft was replaced, the roll wear problem went away.
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Field Report - Reel process audits
Reel equipment can take a beating during normal operation. Periodic inspections of the reel equipment are recommended to develop a baseline with regard to its process variables and mechanical condition.
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Field Report - Retention aid induced press wreck, a case study
Papermaking is as much a chemical process as it is a mechanical one. A fine paper machine lost retention aid flow when the pump shut down. The resulting imbalance caused a press wreck when the pump was restarted. Multiple lessons were learned.