Mold Deflection Calculator
Calculate the maximum deflection of a mold plate under cavity pressure. The calculator determines deflection, maximum stress and safety factor — key data for verifying mold structural integrity and preventing flash.
Input Parameters
Results
Fill in the data and click Calculate
ARGUS automatically verifies mold structural integrity and flags deflection risk
Mold deflection causes flash and dimensional problems — ARGUS verifies structural integrity at every stage of mold design.
How do we calculate mold plate deflection?
Mold plate deflection is the elastic deformation of the plate under cavity pressure. Excessive deflection opens the parting line gap and causes flash, worsens dimensional quality and accelerates mold wear. Deflection is especially critical for large molds with a thin cavity plate.
The calculator uses a rectangular plate model loaded with uniform pressure, accounting for support conditions (simply supported or fixed).
σmax = β × p × (a/h)²
δmax — max. deflection [mm]
σmax — max. stress [MPa]
p — cavity pressure [MPa]
a — plate span [mm]
h — plate thickness [mm]
E — Young's modulus of steel (210 GPa)
α, β — coefficients depending on support type
Allowable mold deflection: up to 0.02 mm for precision parts, up to 0.05 mm for standard parts, up to 0.10 mm for parts without visual requirements. Deflection increases with the fourth power of span and inversely with the third power of plate thickness — doubling the thickness reduces deflection by 8×.
Reducing Mold Deflection
Methods for reducing cavity plate deflection:
Support pillars — reduce the effective span
Fixed support — clamp instead of simply support
Higher-E material — hardened steel instead of soft steel
Support pillars are the most common solution to the deflection problem. They are placed beneath the cavity, reducing the effective plate span. Pillar diameter: 20–50 mm, layout: 80–120 mm grid. Pillars must be precision-fitted to the stationary platen.
Safety Factor
Recommended safety factor: 2.0–3.0 for standard molds, 3.0–5.0 for precision molds. Account for material fatigue — molds operate in cycles (hundreds of thousands of cycles), which can lead to fatigue cracks at stresses below the yield point. ARGUS automatically verifies structural integrity taking mold service life into account.
ARGUS automatically verifies mold structural integrity and optimizes plate design
See for yourself — book a presentation and explore the structural analysis in ARGUS.