How to Adjust The Angle of The Doctor Blade ?

Doctor Blade Adjustment and Angle Requirements

It is crucial to ensure the correct angle of the doctor blade when using it to avoid damaging the surface of the paper roll and cylinder. The following are the detailed steps for adjusting the angle of the blade:

Assembly and Calibration of Doctor Blade

• Firstly, calibrate the doctor blade to be parallel to the surface of the paper roll and cylinder.

• Use a V-shaped ruler to check the horizontal state of the contact surface between the front and rear sides of the doctor blade and the cylinder surface of the paper roll cylinder.

• Check and adjust the angle of the blade. The angle of the blade may vary depending on the usage requirements, blade material, and cylinder surface material. The doctor blade device should be at the appropriate angle with the blade.

• Use a blade angle gauge to check the angle.

• Move the angle gauge back and forth until the pointer displays the diameter of the roll paper cylinder to be checked.

• Press the blade angle gauge onto the cylinder surface of the paper roll cylinder, with the contact point between the doctor blade and the cylinder surface as point A.

• Move the protractor to place the X surface flat on the doctor blade.

• Read the angle from the protractor and adjust the position of the doctor blade until the angles at both ends of the blade are equal.

Fine Tune The Doctor Blade Holder

There are fine adjustment screws on the knife holder. Unscrew the fine adjustment screw and tighten the round head screw on the tool holder. If the knife holder is damaged or cannot cover the back of the doctor blade well, the knife holder needs to be replaced. The newly ground roller surface must be equipped with new doctor blades.

Adjustment of Flat rollers and Crown Rollers

• Starting from the center of the roller surface, loosen a few screws on the doctor blade holder towards both ends each time, and adjust and fine tune the screws.

• Tighten the round head screw again, while repeating the above adjustment steps from the center of the roller surface to both ends of the working and transmission surfaces.

• Check the measurement results to determine the uniform contact between the doctor blade holder and the roller at the crown.

• If necessary, repeat the above adjustment process along the length direction of the doctor blade holder.

• Gently tap the doctor blade with a wooden hammer, and then insert 0.002 points of brass between the roller surface and the blade to check the degree of fit. Note that the doctor blade is loaded very lightly at this time.

By following these steps, you can ensure that the angle of the doctor blade is correct, thereby avoiding damage to the surface of the paper cylinder and improving work efficiency.

To use doctor blades better, it's not enough to just focus on the angle. While the correct angle can protect the roller surface and improve the paper-scraping effect, angle is only one part of doctor blade maintenance and management. To maintain its optimal performance and extend its service life, it's equally important to pay attention to doctor blade installation, solutions to common wear and tear, as well as the location of use and application of doctor blades on paper machines, etc.. Mastering these techniques allows for comprehensive doctor blade optimization, ensuring paper quality and stable, low-cost operations.