Extruding Holes Sheet Metal

If an extruded hole is too close to the part edge it can lead to deformation or tearing of the metal.

Extruding holes sheet metal.

Extrusions our commonly used to accept sheet metal screws or permit tapping into a deeper distance than just the material thickness. Therefore the minimum distance between the extruded hole to edge if maintained. Avoid large sheet metal parts with small bent flanges. For a hole 1 in diameter the minimum distance d 2t r see fig.

Extrusion is the process in which a continuous radial stretch flange is created by expanding a hole. C form height to thickness ratio to determine the minimum form height for sheet metal use the. 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. Extruded hole to part edge b 3t d 2.

The diameter of the pre punched hole ultimately determines the height of the extrusion. Extruded holes very close to the part edge can lead to sheet metal deformation or tearing. Extruding metal is one of the most extreme pressure applications in press working and generates lot of friction and heat. Both holes and regular extrusions are possible in sheet metal as well as thread features.

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. Of all of the factors controlling the success of an extruding operation material type and its mechanical properties are the most influential. The punch should be polished linearly to a mirrorlike surface finish. Relieve the punch after extruding the straight section to allow for lubricant to settle into the negative portion of the punch.

Materials exhibiting good stretch capability and stretch distribution characteristics are best suited for extruding. B for a slot or hole 1 diameter then the minimum distance d 2 5t r see fig. The extrusion punch should be made of highly wear resistant tool steel powdered metal pm preferably or solid carbide material. Center of extruded holes a 5 hole dia 2t extruded hole and bend edge c 3t r d 2.

A pre punched hole is required as a one hit pierce and extrude gives poor hole quality and has limited adjustment on the machine. Can you clarify what you mean by extruded hole. The following illustration shows the extruded hole geometry. 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.