Asymmetric parts naturally demand more material on one side than the other. Without deliberate control, the high-volume side may become thin while the opposite side retains excess material or develops folds.
A temperature gradient, off-center sheet, plug misalignment, unequal clamping, and residual extrusion orientation can intensify the geometry-driven imbalance. The defect may be mistaken for a vacuum problem because one side reaches the tool earlier.
Process development
A thickness map should be paired with sheet-temperature data and tool-motion measurements. Rotating the sheet can reveal directional material behavior. Repeating the process without the plug, where feasible, can show how much asymmetry the mechanical aid introduces.
Pattern heating, an offset or contoured plug, controlled pre-stretch, and revised sheet positioning can direct material toward the high-demand region. The correction should target the known volume requirement instead of attempting to make every heater zone or plug dimension symmetrical.