The punch should be polished linearly to a mirrorlike surface finish.
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 metal is one of the most extreme pressure applications in press working and generates lot of friction and heat.
Unipunch tooling can be used to simultaneously punch a hole and extrude the material down.
Extrusions our commonly used to accept sheet metal screws or permit tapping into a deeper distance than just the material thickness.
A pre punched hole is required as a one hit pierce and extrude gives poor hole quality and has limited adjustment on the machine.
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.
Can you clarify what you mean by extruded hole.
The minimum distance between two extruded holes is six times the material thickness.
Therefore the minimum distance between the extruded hole to edge if maintained.
Avoid large sheet metal parts with small bent flanges.
C form height to thickness ratio to determine the minimum form height for sheet metal use the.
For a hole 1 in diameter the minimum distance d 2t 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.
The extrusion punch should be made of highly wear resistant tool steel powdered metal pm preferably or solid carbide material.
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.
Applications include for self tapping sheet metal screws or in thicker material to permit tapping for machine screws.
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.
B for a slot or hole 1 diameter then the minimum distance d 2 5t r see fig.
Center of extruded holes a 5 hole dia 2t extruded hole and bend edge c 3t r d 2.
Extruded hole to part edge b 3t d 2.
If an extruded hole is too close to the part edge it can lead to deformation or tearing of the metal.
Extruded holes very close to the part edge can lead to sheet metal deformation or tearing.
Extrusion is the process in which a continuous radial stretch flange is created by expanding a hole.
