Plastics Extrusion - Pipe, Film & Profile worked example

Cooling Tank Dwell at 23% extra cooling margin: a worked example

Push extra cooling margin up to 23% and the picture changes. This example computes every intermediate figure at that operating point. Use it when pipe, profile, or sheet cooling capacity may limit haul-off speed or dimensional stability.

The inputs for this scenario

  • Cooling or calibration section length: 60 ft (unchanged)
  • Extrusion line speed: 12 ft / min (unchanged)
  • Extra cooling margin: 23 % (raised for this scenario; the documented default is 20)

Working through the calculation

  • Applying the documented formula (Base time = cooling or calibration length รท line speed) to the inputs above produces each figure below.
  • At this operating point the engine returns 6.15 min for adjusted cooling dwell, the number this scenario is built around.
  • At this operating point the engine returns 5 min for base dwell time.
  • At this operating point the engine returns 23 % for cooling allowance applied.
  • At this operating point the engine returns 12 ft / min for line speed.

How this compares with the baseline

  • Against the tool's baseline example, where extra cooling margin sits at 20% and the headline result is 6 min, this scenario comes in 2.5% above the baseline at 6.15 min.
  • It computes the base residence time of the part in the cooling tank and then applies a cooling margin to give an adjusted target dwell. The value of this scenario is the size of the gap it exposes: that gap, priced out over a year, is the budget you can justify spending to close it.

Results at a glance

  • Adjusted cooling dwell: 6.15 min (headline result)
  • Base dwell time: 5 min
  • Cooling allowance applied: 23 %
  • Line speed: 12 ft / min

Run it with your numbers

  • Every input above is editable in the live Cooling Tank Dwell calculator, which recalculates instantly and can be shared with the inputs intact.

Last reviewed 2026-05-12.