Heat Exchanger, Coil & Radiator Manufacturing worked example
Tube Expansion Time at 12% expansion allowance: a worked example
What does the result look like when expansion allowance reaches 12%? The full calculation is worked below with real intermediate numbers. Use it when mechanical expansion, bullet expansion, mandrel expansion, or roll expansion needs to be scheduled before brazing, leak testing, or final assembly.
The inputs for this scenario
- Tubes to expand: 120 tubes (unchanged)
- Expansion rate: 12 tubes / hr (unchanged)
- Expansion allowance: 12 % (raised for this scenario; the documented default is 10)
Working through the calculation
- Applying the documented formula (Base tube expansion hours = tubes to expand รท expansion rate) to the inputs above produces each figure below.
- At this operating point the engine returns 11.2 hr for adjusted tube expansion hours, the number this scenario is built around.
- At this operating point the engine returns 10 hr for base expansion hours.
- At this operating point the engine returns 12 % for allowance applied.
- At this operating point the engine returns 12 tubes / hr for expansion rate.
How this compares with the baseline
- Against the tool's baseline example, where expansion allowance sits at 10% and the headline result is 11 hr, this scenario comes in 1.82% above the baseline at 11.2 hr.
- A figure at this level is achievable when expansion allowance is genuinely sustained, not just peaked for a shift. It assumes one steady expansion rate; mixed tube diameters, wall thicknesses or alloys that change cycle time mid-batch are not captured by a single rate.
Results at a glance
- Adjusted tube expansion hours: 11.2 hr (headline result)
- Base expansion hours: 10 hr
- Allowance applied: 12 %
- Expansion rate: 12 tubes / hr
Run it with your numbers
- Every input above is editable in the live Tube Expansion Time calculator, which recalculates instantly and can be shared with the inputs intact.
Last reviewed 2026-05-12.