Extruded Sheet Metal Hole

Certain distance should be maintained between two extruded holes in sheet metal designs.

Extruded sheet metal hole.

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. The following illustration shows the extruded hole geometry. Therefore the minimum distance between the extruded hole to edge if maintained. Creating an extruded hole using a punching process requires extreme pressure force.

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. For the tapped screw hole this is typically made using a male punch that creates the hole and extrudes the metal. Applications include for self tapping sheet metal screws or in thicker material to permit tapping for machine screws. Extruded holes unipunch tooling can be used to simultaneously punch a hole and extrude the material down.

If extruded holes are too close it can lead to metal deformation. It is recommended that the minimum distance between two extruded holes should be six times the thickness of sheet metal.