Extruded Sheet Metal Hole

Minimum hole diameter the diameter of the hole in sheet metal part should not be very small small holes are created by piercing operation and for manufacture small holes small sizes punches are required.

Extruded sheet metal hole.

In low carbon steel sheet metal the minimum radius of a bend should be one half the material thickness or 0 80 mm. Avoid large sheet metal parts with small bent flanges. Die buttons with oversized internal diameters typically with a 020 radius instead of a cutting edge are used to permit the material to flow downward and punch an extruded hole. Creating an extruded hole using a punching process requires extreme pressure force.

Extrusions our commonly used to accept sheet metal screws or permit tapping into a deeper distance than just the material thickness. Alternately the hole could be pre pierced in a separate station and then the edges extruded at a second station. Therefore the minimum distance between the extruded hole to edge if maintained. Applications include for self tapping sheet metal screws or in thicker material to permit tapping for machine screws.

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. Design for manufacturability sheet metal guidelines bends for the ease of manufacturing multiple bends on the same plane should occur in the same direction. In a sheet metal design specifying hole sizes locations and their alignment is critical. 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. This procedure creates in effect the. By the way i can only punch the extruded screw hole the other feature i need with a very. It is always better to specify hole diameters that are greater than the sheet s thickness t.

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.