Extruding Holes Sheet Metal

Of all of the factors controlling the success of an extruding operation material type and its mechanical properties are the most influential.

Extruding holes sheet metal.

Avoid large sheet metal parts with small bent flanges. Extruded holes very close to the part edge can lead to sheet metal deformation or tearing. Extrusions our commonly used to accept sheet metal screws or permit tapping into a deeper distance than just the material thickness. For a hole 1 in diameter the minimum distance d 2t r see fig.

Center of extruded holes a 5 hole dia 2t extruded hole and bend edge c 3t r d 2. The following illustration shows the extruded hole geometry. Extruded hole to part edge b 3t d 2. The minimum distance between two extruded holes is six times the material thickness.

C form height to thickness ratio to determine the minimum form height for sheet metal use the. Applications include for self tapping sheet metal screws or in thicker material to permit tapping for machine screws. Both holes and regular extrusions are possible in sheet metal as well as thread features. If an extruded hole is too close to the part edge it can lead to deformation or tearing of the metal.

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. Extruding metal is one of the most extreme pressure applications in press working and generates lot of friction and heat. In low carbon steel sheet metal the minimum radius of a bend should be one half the material thickness or 0 80 mm 0 03 inch whichever is larger. 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.

Unipunch tooling can be used to simultaneously punch a hole and extrude the material down. The punch should be polished linearly to a mirrorlike surface finish. A pre punched hole is required as a one hit pierce and extrude gives poor hole quality and has limited adjustment on the machine. The diameter of the pre punched hole ultimately determines the height of the extrusion.

The extrusion punch should be made of highly wear resistant tool steel powdered metal pm preferably or solid carbide material. Therefore the minimum distance between the extruded hole to edge if maintained. Extrusion is the process in which a continuous radial stretch flange is created by expanding a hole. Can you clarify what you mean by extruded hole.