Root Interface Condition Analysis
In digital 3D modeling environments, solid bodies exist in a frictionless zero-tolerance state where planar faces glide together without physical resistance. During physical prototype assembly, stacked manufacturing variations on sheet metal bends and machined bosses produced an interference of 0.35 mm across the secondary mating interface, causing instant binding.
CAD geometry assumed perfectly orthogonal mating planes and concurrent fastener seating without deflection under clamp loads.
Physical parts exhibited slight angle drift and thermal powder-coat buildup, forcing technicians to force alignment with drift pins.
Dimensional & Tolerance Interplay
The failure stemmed from redundant dimensional constraints. By locating the mating bracket across two rigid planar faces simultaneously while maintaining tight pin-hole fits, the design overconstrained the horizontal axis. Eliminating the duplicate locating pad and converting one round dowel hole into a slotted relief restored immediate hand-assembly without binding.