The Hazards of Excessive Doctor Blade Wear
In paper making, doctor blades are key components for controlling paper width, cleaning roller surfaces, and ensuring paper surface quality. Once they are severely worn, they will not only affect equipment performance and efficiency, but also trigger a series of chain problems and even lead to production interruptions. Below, Sun Hong will discuss the specific hazards of excessive wear of doctor blades and provide corresponding precautions and solutions.
Why Doctor Blades Wear Out?
Material mismatch: The hardness of the doctor blade is not coordinated with the roller surface, resulting in increased wear.
Improper installation: The angle and pressure of the doctor blade are not set properly, resulting in accelerated local wear.
Process or medium influence: Fillers and chemicals in the pulp may also corrode the doctor blade.
Poor condition of equipment such as rollers: If the dynamic balance of the roller is unbalanced or the bearings are worn, vibration will be generated during operation, which will destroy the stable contact state between the doctor blade and the roller surface, forming an impact and significantly increasing the wear of the doctor blade.
What Hazards May Occur After the Doctor Blade is Worn?
As the doctor blade wears, the contact area between the blade tip and the roller surface increases. Even if the pressure remains unchanged, the contact area with the roller surface increases, and the actual pressure transmitted to the roller surface will also decrease. This will lead to a decrease in the roller surface cleaning or dehydration ability, and even paper breakage, which will have a serious impact on normal papermaking production.
If the worn doctor blade is continued to be used and the loading pressure is increased to improve the scraping effect, the doctor blade may be deformed by pressure into a "bird's beak" shape, resulting in uneven cleaning of the roller surface and damage to the roller surface.
If the paper sheet is peeled off, the possibility of the paper sheet passing under the doctor blade and causing roller entanglement is greatly increased.
How to Effectively Prevent Excessive Wear of the Doctor Blade?
Select the appropriate doctor blade material for different roller surfaces according to professional advice.
Regularly check the doctor blade system settings and blade wear.
Replace the doctor blade in time and do not continue to use excessively worn blades by increasing the loading pressure.
Pay attention to the spray lubrication of the doctor blade in the wet section of the papermaking machine.
Strictly set the doctor blade angle and pressure according to the requirements, avoid overtightening and deflection, and ensure uniform force in the contact state.
Although the doctor blade is a small accessory, it is an indispensable equipment in the operation of the paper machine. Its wear is not caused by a single reason. We need to take into account the combined effects of parameters, process materials, equipment status and maintenance. To effectively alleviate wear, we must deeply analyze the causes of doctor blade wear and implement effective preventive measures to maximize the service life of the doctor blade and ensure the operation of the paper machine and control production costs.
