Search results

Sources and solutions for several common doctoring problems

One of the main causes for doctoring problems is the loading tube, which may be kinked, leaking or incorrectly pressurized. Additionally, there are a number of failure points such as pivot brackets, pivot rods, blade wear and sequencing.

Avoid common workplace injuries by using safe material handling

Most workplace injuries (almost 60%) are the result of common, everyday missteps such as overexertion and slips/trips/falls - not from violent events.

Troubleshooting headbox corrosion, plus an analysis case study

Imperfections in a headbox's finish interfere with fiber flow through its chambers, resulting in sheet uniformity problems and a poor end product. A process and condition test can identify problems caused by corrosion, fiber orientation and machine limitations.

Apron lip mapping and repair avoid production quality problems

Apron lip damage usually comes in the form of nicks, scratches or dents. These minor abrasions can trap fibers from the pulp or cause distortions in the flow of the headbox jet, which jeopardizes sheet formation. Preparation before apron repairs can improve maintenance safety and save money.

Problematic retention aid system leads to press wreck, 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.

Protect costly soft roll covers with novel mechanical devices

Soft rolls represent a significant investment for mills, yet they are susceptible to damage, especially if the surface temperature varies too much across the face of the roll. This article describes the design, operation and maintenance of some of the most common soft roll protection devices.

Proper bearing lubrication and modernization are essential

Most bearing failures can be traced to two maintenance oversights: a lack of lubrication or the use of the wrong type of lubrication. An upgrade may be needed.

Hot water modules for calender rolls, recommended maintenance

Calender rolls are heated via heating modules to provide low-variance accurate roll temperatures. Follow these hot water module maintenance best practices.

Vibration analysis - introduction to techniques and equipment

This article provides a clear, effective and illustrated introduction to vibration analysis techniques, including principles, equipment and spectral analysis.

Web shifting - base paper, misalignment, free span and process

Web shifting can be caused by the paper or by something mechanically wrong in the web path. This article presents typical causes of sheet shifting. Most have to do with alignments, but base paper, drying and coating also have great impact.