The extruded profile does not maintain proper squareness or flatness. Surfaces that should be perpendicular or planar show angular deviation or distortion.

Gas-related surface blisters appear on the extrusion.

The extrusion exhibits outward bulging or convex deformation, often in hollow sections with light or uneven walls.

The extrusion shows smooth longitudinal curvature, often appearing after cooling or handling.

Periodic vibration or chatter marks appear, sometimes accompanied by snap-ring type surface damage.

Thin-wall sections show angular distortion due to die deflection under load.

Die requires unusually high force to extrude material.

A localized depression forms on an otherwise flat surface of the extrusion.

Abnormally high extrusion pressure causes tooling deflection and profile instability.

The profile deviates from a flat plane across its width or length, affecting dimensional accuracy and assembly fit.

Internal cracking or tearing occurs inside hollow sections.
sometimes visible from outside, but only in extreme cases); causes scrap, defective extrusions and possible wall thickness problems;

A hollow profile inflates primarily at the center while outer regions remain stable, usually under high pressure or speed.

Cracks form in the extrusion due to thermal and stress conditions.

Wall thickness inconsistency appears after nitriding treatment, despite prior stable production.

Aluminum adheres to die surfaces, transferring defects to the profile.

The extruded profile does not accurately follow the intended contour, including radii, transitions, or surface geometry.

Internal welds are weak or incomplete, leading to reduced mechanical integrity.

Only a portion of the profile experiences metal starvation while the rest appears normal.

A round extrusion becomes oval or egg-shaped rather than maintaining a uniform circular cross-section.

Layers of material overlap or fold within the extrusion, producing a sandwich-like defect.

Material tearing occurs around screw bosses, compromising strength and geometry.

Profiles from different holes shift relative to each other, causing non-uniform geometry.

Walls shift position relative to intended geometry, often progressively during production.

Certain wall sections receive insufficient metal flow, leading to incomplete fill or weak areas.

Surface streaks appear along the extrusion length, affecting appearance and sometimes performance.

In multi-hole dies, mandrels shift outward, producing thin walls in outer cavities.

Thin areas near heavy sections become excessively thin, such as near screw bosses or extremities.

Weld lines form between successive billets.

The profile rotates along its longitudinal axis during extrusion or cooling, increasing with length.

Rod or extrusion length varies due to flow or alignment issues.

Walls of equal design thickness extrude with unequal actual thickness.

Wall thickness inconsistency increases with repeated runs of the same die.

Wall thickness varies beyond tolerance and may change during the extrusion run.

The profile displays periodic wave-like distortion along its length, often worsening toward the billet back end.

Waviness combined with localized thin wall sections, either along the full length or partial areas.

Visible weld lines appear on exposed surfaces, potentially affecting strength or appearance.