Extrusion and drawing both force material to change cross-section as it passes through a die, but the dominant applied force differs.

In extrusion, a ram pushes the workpiece through the die. In drawing, material is pulled through the die from the exit side.

For a change from cross-sectional area $A_0$ to $A_1$, a useful ideal logarithmic strain is

$$\varepsilon=\ln\left(\frac{A_0}{A_1}\right).$$

A rod reduced from $100\ \mathrm{mm^2}$ to $70\ \mathrm{mm^2}$ has

$$\varepsilon=\ln(100/70)\approx0.357.$$

Extrusion can produce long products with constant complex cross-sections. Drawing is widely used for wire, rod and tube reduction where tensile pulling can be applied effectively.

Die angle and friction create a trade-off. A very shallow die increases contact length and frictional work; a very steep die produces more redundant internal deformation. There is therefore no universally best angle independent of material, reduction and lubrication.

Drawing is also limited by the tension that the exiting material can carry. Large reductions may require multiple passes with intermediate heat treatment.

These processes show how die geometry redirects plastic flow into useful continuous shapes while process force, friction and material ductility constrain the achievable reduction.