HVAC Ductwork, Air Handling & Mechanical Products worked example

Flange Count at 99% roll-forming line uptime: a worked example

What does the result look like when roll-forming line uptime reaches 99%? The full calculation is worked below with real intermediate numbers. Use this when scheduling TDC (transverse duct connector) or TDF (transverse duct flange) roll-forming production to support a ductwork fabrication run. Flange count determines how much connection hardware needs to be formed and staged before duct sections reach the assembly station. If the flange line cannot keep up with the duct fabrication line, it becomes the bottleneck.

The inputs for this scenario

  • Flange sets produced per roll-forming setup: 6 sets / setup (unchanged)
  • Available roll-forming setups per shift: 80 setups (unchanged)
  • Roll-forming line uptime: 99 % (raised for this scenario; the documented default is 92)
  • First-pass flange dimensional yield: 97 % (unchanged)

Working through the calculation

  • Applying the documented formula (Gross flange output = flange sets per setup × available setups) to the inputs above produces each figure below.
  • At this operating point the engine returns 461 units for good output capacity, the number this scenario is built around.
  • At this operating point the engine returns 480 units for gross capacity.
  • At this operating point the engine returns 4.8 units for uptime loss.
  • At this operating point the engine returns 14.26 units for yield loss.

How this compares with the baseline

  • Against the tool's baseline example, where roll-forming line uptime sits at 92% and the headline result is 428 units, this scenario comes in 7.61% above the baseline at 461 units.
  • A figure at this level is achievable when roll-forming line uptime is genuinely sustained, not just peaked for a shift. It assumes a steady-state shift; major coil changeovers, die swaps for a different flange profile, or a corner-piece shortage can drop real output below the calculated count.

Results at a glance

  • Good output capacity: 461 units (headline result)
  • Gross capacity: 480 units
  • Uptime loss: 4.8 units
  • Yield loss: 14.26 units

Run it with your numbers

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

Last reviewed 2026-05-12.