Doctor Blades For Paper Machines

Doctor Blades

Doctor blades for paper machines divide into press doctor and dryer doctor, although this component is small relative to the entire paper machine, it has an important effect on the quality of the paper. So do you know the function of doctor in every section? And how to maintain the doctor blades to extend his life?

The doctor blades is mainly composed of six parts, including frame, doctor fixture, doctor, pressure relief device, bearing and swing device.

1.  Frame

The deflection of the frame should be less than 0.01mm, the maximum length of the maximum allowable deflection of 2.5mm. The total deviation of the combined frame should not be greater than 0.13mm.

2. Doctor fixture

The fixture should be adjustable, sufficient rigidity and self-sealing. The fixture should be able to meet the requirements for quick and easy loading and removal of the blade

3. Doctor

a: The material of the blade must match the material of the roller surface.

b: The mounting angle of the blade relative to the drum must be correct.

c: The blade must be in close contact with the drum surface.

Doctor blades wear and cause analysis

phenomenon Reason Approach Remarks
Uneven wear Roll uneven

The fixture is damaged


Use a softer doctor

Clean the fixture

Use a wear doctor


Middle or end wear serious Doctor do not match the roll

Long-term use cause doctor over-contact or virtual contact

Reload and use the gasket to adjust the relationship between the fixture and the doctor holder

Replace the new doctor

Was zigzag Fouling on the roll

Doctor pressure is too large

Material excellent

Use a wear doctor

relieve pressure

Use a softer doctor