Surface Engineering & Aerospace

Shot Peening & Abrasive Blasting Coverage Calculator

Calculate Almen strip arc height intensity ($I_{\text{Almen}}$ in A/N/C strips), particle impact velocity ($v_p$), single dimple indent diameter, and saturation coverage ($T_{\text{sat}}$) for aerospace gears, springs, and turbine blades.

1. Input Parameters

Shot Peening Media & Size:

Standard SAE J444 shot media type and nominal sphere diameter.

Nozzle Air Pressure (P in bar):

Compressed air blast pressure at the venturi nozzle inlet.

Impingement Angle (θ in degrees):

Angle between nozzle centerline and target component surface (optimal: 75° - 90°).

Nozzle Standoff Distance (H in mm):

Distance from nozzle exit orifice to component face.

Target Material Yield Strength (σ_y in MPa):

Yield strength of substrate (e.g. 4340 Steel, Ti-6Al-4V, 7075-T6).

Exposure / Dwell Time (t in sec):

Robotic blast raster dwell time per unit surface area.

2. Calculation Results

Estimated Almen Intensity

0.014 A (0.36 mm)

Single Dimple Diameter

0.24 mm

Visual Surface Coverage

98.4 %

Time to 100% Saturation

5.2 s

3. Geometric Visualizer

Tooling & Vector Prepress Engineering Notes

Shot Peening & Almen Saturation Physics: Shot peening bombards metal surfaces with spherical media at high velocities (40–80 m/s), creating plastic dimple indentations that introduce beneficial compressive residual stress layers (-600 to -1200 MPa) to resist fatigue cracking and stress corrosion:

Almen Intensity (Arc Height) ∝ d_shot^0.5 × v_p^1.2 × sin(θ)
Coverage C(t) = 1 - exp(-n_dot × A_dimple × t) × 100%
T_sat (98% Coverage) ≈ -ln(0.02) / (n_dot × A_dimple)

Robotic Vector Toolpaths & Masking: Program robotic multi-axis blast nozzles with continuous serpentine raster toolpaths (50%–60% spray cone overlap). Laser-cut polyurethane or hardened steel shadow masks require 25°–35° chamfered deflection edges to prevent ricochet boundary erosion on critical bearing journals.