Thermoforming & Vacuum Formed Products worked example

Forming Pressure Margin with available forming and vacuum pressure of 63 psi: a worked example

This worked example runs the forming pressure margin numbers for a tougher week than the baseline: available forming and vacuum pressure of 63 psi instead of the typical 125 psi. Forming Pressure Margin is the safety headroom between the pressure your thermoforming system can deliver and the pressure a specific part actually needs to detail out.

The inputs for this scenario

  • Available forming/vacuum pressure: 63 psi (the input this scenario stresses; the baseline uses 125)
  • Required forming pressure for the part: 100 psi (held at the documented default)
  • Reference pressure for percent margin: 100 psi (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Forming Pressure Margin margin = available value - required value.
  • Absolute margin works out to -37 psi at these inputs, and this is the headline figure for the scenario.
  • Margin works out to -37 % at these inputs.
  • Available amount works out to 63 value at these inputs.
  • Required amount works out to 100 value at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where available forming and vacuum pressure sits at 125 psi and the headline result is 25 psi, this scenario comes in 248% below the baseline at -37 psi.
  • Use it when qualifying a mold on a given former, transferring a job to a different machine, or diagnosing intermittent detail-out problems on marginal parts. A result at this level usually justifies acting on the stressed input before touching anything else, because every other figure in the table is downstream of it.

Results at a glance

  • Absolute margin: -37 psi (headline result)
  • Margin: -37 %
  • Available amount: 63 value
  • Required amount: 100 value

Run it with your numbers

  • To rerun this with your own numbers, open the live Forming Pressure Margin calculator, set available forming and vacuum pressure to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.