Impact Extrusion

Impact Extrusion

What is Impact Extrusion? is a manufacturing process similar to extrusion and drawing by which products are made with a metal slug. The slug is pressed at a high velocity with extreme force into a die or mold by a punch. a discrete manufacturing process, in which a metal part is extruded through the impact of a die with the work stock. The part is formed at a high speed and over a relatively short stroke.

Impact extrusion is most often performed cold. Occasionally with some metals and thicker walled structures, the work is heated before impact forming it. This process is best suited for softer metals.Mechanics and Design of Impact ExtrusionsDuring impact extrusion, a work piece is placed into a mold and is struck with great force, causing the metal to flow into position in an instant. Tooling must have: sufficient impact resistance, fatigue resistance, and strength.Types of Impact ExtrusionForward Impact ExtrusionMaterial is forced forward by the punch through an orifice in the die, producing a smaller cross section than the initial slug. 75% reductions are possible with this technique.Metal flows in the same direction that the force is delivered.

Reverse Impact ExtrusionMaterial is contained in the die and forced backward around the punch, producing blind holes and cups. The bottom of the cup should be thicker than the walls. Area reductions of 20-75% are possible with this technique. The metal flows in the opposite direction that the force is delivered.

Combination Impact Extrusion As many designs include both extrusions, the creativity of the design engineer can enable both techniques to be used simultaneously to minimize production costs.In combination, the metal flows in both directions.

The end of the punch is better designed not to be completely flat, to avoid slipping at the punch-work interface.

Another factor, when manufacturing by this process, is the proportion between an impact extrusion's length and its internal diameter. Long punches with relatively small diameters may fail during manufacture.

Advantages and DisadvantagesSpeedEconomyStrengthToughnessVersatilityConsolidationSize VariancesProduct Limitations