Extruded Sheet Metal Hole

Alternately the hole could be pre pierced in a separate station and then the edges extruded at a second station.

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. Applications include for self tapping sheet metal screws or in thicker material to permit tapping for machine screws. Extruded holes very close to the part edge can lead to sheet metal deformation or tearing. If extruded holes are too close it can lead to metal deformation.

For the tapped screw hole this is typically made using a male punch that creates the hole and extrudes the metal. 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. 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.

Certain distance should be maintained between two extruded holes in sheet metal designs. Therefore the minimum distance between the extruded hole to edge if maintained.