Demolding Force Calculator
Demolding (ejection) force from the projected area of the gripped section and the draft sine.
Inputs
sin α must be between −1 and 1.
Results
Unrounded values
How this calculator works
PDCPD shrinks onto cores and ribs as it cures, so the ejection system has to overcome the grip on those features. The required force depends on the gripped area and on the draft angle.
This calculator estimates the demolding force from the projected area of the gripped section and sin α, using fixed empirical factors.
Formulas
- Demolding force
projected area × 12 × 0.1019716 × 0.2 × sin α
The source sheet labels this unit "KgN", which is ambiguous. The value is shown unconverted; confirm the unit before using it for selection.
Worked example
A gripped section with 10,000 mm² projected area and sin α = 0.1:
| Projected area of gripped section | 10000 mm² |
|---|---|
| sin α | 0.1 |
| Demolding force | 244 |
|---|
When to use it
- Sizing ejector cylinders and air-assist systems
- Comparing the effect of more draft on deep features
Frequently asked questions
How do I calculate the demolding force?
Force = projected area × 12 × 0.1019716 × 0.2 × sin α, with the area in mm². For 10,000 mm² and sin α = 0.1 the result is about 244.7.
Do I enter the angle or its sine?
Enter the sine. For a 30° angle enter 0.5; for about 5.7° enter 0.1.
What unit is the result in?
The source sheet labels it "KgN", which is ambiguous. Treat the value as indicative and confirm the unit before using it for ejector selection.
Related calculators
Results are estimates from empirical rules used in PDCPD mold development. Verify critical dimensions before cutting metal.