Extruding Holes Sheet Metal

Relieve the punch after extruding the straight section to allow for lubricant to settle into the negative portion of the punch.

Extruding holes sheet metal.

Materials exhibiting good stretch capability and stretch distribution characteristics are best suited for extruding. For a hole 1 in diameter the minimum distance d 2t r see fig. Therefore the minimum distance between the extruded hole to edge if maintained. The punch should be polished linearly to a mirrorlike surface finish.

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. A pre punched hole is required as a one hit pierce and extrude gives poor hole quality and has limited adjustment on the machine. C form height to thickness ratio to determine the minimum form height for sheet metal use the. B for a slot or hole 1 diameter then the minimum distance d 2 5t r see fig.

Applications include for self tapping sheet metal screws or in thicker material to permit tapping for machine screws. Can you clarify what you mean by extruded hole. 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.

Extrusion is the process in which a continuous radial stretch flange is created by expanding a hole. The minimum distance between two extruded holes is six times the material thickness. The extrusion punch should be made of highly wear resistant tool steel powdered metal pm preferably or solid carbide material. Both holes and regular extrusions are possible in sheet metal as well as thread features.

The diameter of the pre punched hole ultimately determines the height of the extrusion. Extruded hole to part edge b 3t d 2. Extrusions our commonly used to accept sheet metal screws or permit tapping into a deeper distance than just the material thickness. Extruded holes very close to the part edge can lead to sheet metal deformation or tearing.

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. Avoid large sheet metal parts with small bent flanges. Center of extruded holes a 5 hole dia 2t extruded hole and bend edge c 3t r d 2.