Extruded Sheet Metal Hole

If extruded holes are too close it can lead to metal deformation.

Extruded sheet metal hole.

An extruded hole is one that is generated at one station using a specially stepped punch that first shears a smaller hole and then follows through to deform the local area around the hole into a projection by limited forward extrusion. The following illustration shows the extruded hole geometry. Alternately the hole could be pre pierced in a separate station and then the edges extruded at a second station. You can imagine the shape as being a body to the punch of any shape and from this protrudes the punch pin of the diameter you want.

Certain distance should be maintained between two extruded holes in sheet metal designs. Creating an extruded hole using a punching process requires extreme pressure force. Extruded holes unipunch tooling can be used to simultaneously punch a hole and extrude the material down. Applications include for self tapping sheet metal screws or in thicker material to permit tapping for machine screws.

Tap fix screws for extruded holes in light gauge steel this article provides tap fix hole size recommendations for metals using light gauge punched extruded materials. For the tapped screw hole this is typically made using a male punch that creates the hole and extrudes the metal.