How to Produce The Doctor Blade ?

Production Process of Doctor Blade

Doctor Blade Raw Material Pre-treatment

• Raw Material Screening: Special blade substrates such as high-speed steel, cemented carbide, stainless steel, carbon steel, and ceramic coating substrates are selected and graded according to hardness, wear resistance, and corrosion resistance.

• Leveling & Stress Relieving: Leveling of coils/plates to eliminate rolling stress, ensuring flatness ≤ 0.02mm/m.

• Surface Cleaning: Degreasing, derusting, and oil removal to eliminate surface oxide layers and impurities.

Cutting and Forming

• Material Cutting: Shearing/slitting according to doctor blade specifications (length, width, thickness), controlling dimensional tolerance ±0.05mm.

• Precision Cutting: CNC shearing machine and laser cutting machine are used for contour cutting to adapt to the installation size of the doctor blade holder.

Heat Treatment (Core Process)

• Quenching: High-temperature quenching (800-1200℃) to improve substrate hardness; hardness of high-speed steel doctor blade reaches HRC62-65.

• Tempering: Low-temperature tempering to eliminate quenching stress, stabilize dimensions, enhance toughness, and prevent chipping during use.

• Quenching & Tempering: Adjust the ratio of hardness and toughness according to blade application scenarios (drying section, press section, forming section).

Precision Grinding

• Rough Grinding: Grinding of flat and side surfaces to remove heat treatment deformation and ensure parallelism.

• Finish Grinding: Precision grinding of cutting edges, controlling edge angle (15°-30°) and thickness tolerance ±0.01mm.

• Polishing: The doctor blade surface is polished to reduce the coefficient of friction and avoid scratching the surface of the dryer cylinder and roller.

Surface Treatment (Improve Durability)

• Coating Treatment: PVD/CVD coating (titanium nitride, titanium carbide, ceramic coating) to enhance wear and corrosion resistance.

• Chrome/Nickel Plating: Surface chrome plating to enhance rust prevention and extend service life.

• Passivation Treatment: Special passivation for stainless steel doctor blade to improve acid and alkali corrosion resistance.

Finishing and Grooving

• Drilling/Grooving: CNC drilling and grooving according to installation requirements to adapt to the fixing method of the doctor blade holder.

• Chamfering & Deburring: Chamfering of edges and cutting edges to remove burrs and avoid scratches during installation.

• Dimensional Inspection: Re-inspection of all dimensions to ensure compliance with paper machine installation standards.

Quality Inspection and Packaging

• Hardness Testing: Rockwell hardness tester to ensure hardness meets standards.

• Straightness Testing: Inspection of doctor blade edge straightness and flatness, free of bending deformation.

• Appearance Inspection: No cracks, chipping, or coating peeling.

• Packaging: Anti-rust treatment + moisture-proof packaging, marked with specifications, material, and applicable models.