Removing doctor blades can be a challenging task. The function of a doctor blade is to scrape glues, wood pitch, stickies, and fibers from rolls. These materials work into the blade holder to complicate blade removal. After a shutdown cycle, the blades become very difficult to remove. To add risk, the blade is worn and extremely sharp. Without the proper tools, pulling a sharp blade from a holder with compacted fibers, glues, and wood pitch is a safety risk.
There are two forces required to remove a doctor blade: grip force and pull force. It is not uncommon to require the use of an external power source such as a tow motor or come-along cable to generate enough pull force to remove a doctor blade. The grip force of current tools are not great enough to overcome the pull force required to extract a doctor blade. Therefore, blade changes can take hours and consume valuable resources during a shutdown. Too often, blade removal attempts are aborted prematurely for these reasons, leaving worn out blades in place.
With a clear picture of the inefficiencies of the conventional tools, one of our front line team members developed a successful blade removal tool called the BladeShark™ Doctor Blade Extractor using three design requirements:
- As the pull forces increases, the grip force must also increase.
- The design needs to be robust and modular.
- It must be rugged enough for mill use.
The following video link depicts the BladeShark™ doctor blade extractor in action. Purchase the tool online at catalog.kadant.com or contact your local Kadant sales manager for more information.