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.

The extrusion punch should be made of highly wear resistant tool steel powdered metal pm preferably or solid carbide material. 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. Relieve the punch after extruding the straight section to allow for lubricant to settle into the negative portion of the punch.

The punch should be polished linearly to a mirrorlike surface finish. 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. 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. The minimum distance between two extruded holes is six times the material thickness. Materials exhibiting good stretch capability and stretch distribution characteristics are best suited for extruding. Extruded hole to part edge b 3t d 2.

Therefore the minimum distance between the extruded hole to edge if maintained. Can you clarify what you mean by extruded hole. Unipunch tooling can be used to simultaneously punch a hole and extrude the material down. Extruding metal is one of the most extreme pressure applications in press working and generates lot of friction and heat.

B for a slot or hole 1 diameter then the minimum distance d 2 5t r see fig. 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. Center of extruded holes a 5 hole dia 2t extruded hole and bend edge c 3t r d 2. Applications include for self tapping sheet metal screws or in thicker material to permit tapping for machine screws.

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