Selection of Doctor Blades and Rolls

Controlling production processes is key to staying competitive. That is why choosing the right doctor blade material for each machine section is so important.

The aim is to keep costs low and quality high. This applies to all paper and board machines, every operating condition and paper grade, plus many other industrial applications.

Use this quick guide to select Doctor blades and achieve optimum doctoring performance:

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FORMING SECTION

Angle / Pressure: 20° / 0.5 pli

• Fiberglass – Long service life, effective roll cleaning
• Polymeric – For soft rolls; water presence usually extends life
• Micarta – Cost‑effective; often removes tacky deposits better than polymers

PRESS SECTION

Granite / Synthetic / Ceramic Rolls

Angle / Pressure: 25–30° / 1–2 pli

• Fiberglass – Better wear resistance than metal; provides light polishing
• Carbon Fiber – Top performance; maximises blade and roll life
• Stainless Steel – Less widely used today
• Abrasive Type – For trailing blades; preserves roll porosity

Soft Rolls

Angle / Pressure: 20° / 0.5 pli

• Polyethylene – For rubber / PU rolls above 10–15 P&J hardness; works best with lubrication
• Micarta – Typically ¼‑inch thick on soft rubber rolls; not suitable for polyurethane

DRYER SECTION

Angle / Pressure: 30° / 1–2 pli

• Fiberglass – Longer life; less risk of roll damage compared with metal
• Carbon Fiber – Highest wear resistance; strong against bending; excellent cleaning
• Metal – Steel, stainless steel, bronze
• Abrasive Type – Removes built‑up deposits at intervals; only for oscillating doctors

CALENDERS

Angle / Pressure: 30° / 1–2 pli

• Fiberglass – Superior cleaning; longer blade and roll life
• Carbon Fiber – Longest available service life; oscillation recommended
• Metal – Steel, stainless steel, bronze
• Micarta – Various grades available (e.g. Spec 277); low cost but shorter life and lower efficiency

REELS

Angle / Pressure: 30° / 1–2 pli

• Fiberglass – Outlasts metal blades; minimises roll marking
• Carbon Fiber – Longest possible service life
• Metal – Steel and bronze are standard choices