Ordliste
Draft angle — definition
The slight taper on every face parallel to the draw direction, so the part releases from the die.
Without draft the part sticks. Metal shrinks onto the cores as it solidifies, and a perfectly vertical wall will drag against the steel through the entire ejection stroke — or be torn by the ejector pins.
As general industry practice, external faces need less draft than internal ones, because the part shrinks away from the outer walls and onto the cores. Deep ribs and tall cores need more than shallow ones.
Practical consequence for a designer: draft affects dimensions. A wall 3 mm thick at the top is thicker at the bottom. If one of those dimensions is critical, the drawing has to state where on the face it applies.