Extruded Sheet Metal Hole

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

Extruded sheet metal hole.

It is recommended that the minimum distance between two extruded holes should be six times the thickness of sheet metal. Extruded holes very close to the part edge can lead to sheet metal deformation or tearing. For the tapped screw hole this is typically made using a male punch that creates the hole and extrudes the metal. Certain distance should be maintained between two extruded holes in sheet metal designs.

The following illustration shows the extruded hole geometry. 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. Therefore the minimum distance between the extruded hole to edge if maintained. 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.

Alternately the hole could be pre pierced in a separate station and then the edges extruded at a second station. Applications include for self tapping sheet metal screws or in thicker material to permit tapping for machine screws.