Examining Yankee Health by Understanding Blade Wear

Maintenance
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The tissue making industry is dynamic with new assets under construction, older assets that are aging and paying the bills, and on the back end of the process, assets that are being retired and scrapped.

Smart and savvy industry leaders are always trying to get the most out of their assets. Accomplishing this boils down to staying competitive with marketing, niche products, or having management that keeps you in the game and profitable.

Kadant Solutions has been working with tissue makers for decades and in recent years have advanced its technical abilities to keep tissue makers in the game longer, prolong asset life, and keep assets out of the scrap heap. By taking an in-depth look at the creping doctor blade wear patterns and angles, problems can be predicted and solved.

In the past, the tissue maker had limited tools to keep Yankee operation under control. The tools were limited to:

  • Visual inspections with flash lights
  • Strobe lights
  • Nip Impressions
  • Used blade analysis
  • Yankee torque analysis
  • Periodic vibration sampling
  • Sheet pull outs

Used properly, these tools could help keep the Yankee rolling. Advanced technologies have developed tools to examine the Yankee health under dynamic running conditions including:

  • Real time vibrations of the doctors
  • Yankee film thickness measurements
  • Yankee temperature and shape modeling
  • Used blade wear angle and wear pad measurements

The vibration information helps reduce behaviors where the doctor blade vibration is excessive and can lead to Yankee surface damage. Film thickness measurement assists the chemical program and Yankee temperature management. The Yankee shape and temperature model aids in the heat management of the Yankee. Finally, the used blade wear analysis provides feedback on blade loading, moisture profile, and Yankee surface uniformity.

Used creping and cleaning doctor blades have been in intimate contact with the Yankee surface and any unusual wear patterns are the result of factors that need to be addressed to maximize

the utility of the Yankee and tissue manufacturing equipment. The issues that can be a result of unusual blade wear can be lumped into three basic categories.

Moisture Profile

  • Clothing wear or soiled
  • Roll condition
  • Headbox uniformity

Blade Loading

  • Cylinder condition
  • Mechanisms and hardware

Yankee Surface Feedback

  • Chemistry performance
  • Drying uniformity
  • Creping quality

Kadant Solutions created the Blade View™ measurement device to help perform blade wear analysis quickly. The device is portable allowing used blades to be measured and analyzed in the mill the same day. The data generated is used to calculate the wear rate, profile wear angles, and compare the findings to previous data collected. Reliable blade wear information is a key piece of the troubleshooting process and daily management of Yankee health.

Source: Kadant