Calculate average nip contact pressure or reverse load from measured contact width, or use a projected roll-diameter estimate, with line load and residence time.

All visible numeric inputs are required unless labeled optional.

Nip Load (Line Load) Formula

The following example problem outlines the steps and information needed to calculate the nip load (more precisely, the nip line load: force per unit roll length).

NL = P × NW × t

Variables:

  • NL is the nip line load (force per unit roll length), e.g., N/mm (equivalently kN/m)
  • P is the average/adjusted nip pressure, e.g., N/mm² (or Pa, bar, psi)
  • NW is the nip width ratio (dimensionless), commonly defined as (nip/contact width) ÷ (material thickness)
  • t is the material thickness (a length), e.g., mm, cm, m, in

To calculate the nip line load, multiply the average/adjusted nip pressure by the nip width, where nip width = (nip width ratio) × (material thickness).

How to Calculate Nip Load?

The following steps outline how to calculate the nip load (line load).

  1. Determine the nip width ratio (NW).
  2. Measure the material thickness (t) and determine/estimate the average/adjusted nip pressure (P).
  3. Use the formula NL = P · NW · t.
  4. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

nip width ratio (NW) = 2

material thickness (t) = 0.5 mm

average/adjusted nip pressure (P) = 1 N/mm²

NL = P · NW · t = 1 · 2 · 0.5 = 1 N/mm