Extrusion press and tube press and method for separating a butt
The invention relates to an extrusion press or tube press ( 1 ), in particular for aluminum or aluminum alloys, comprising a press frame which consists of a cylinder bar and a counter bar ( 3 ) connected thereto, and in which a moving bar and a moving block receiver ( 2 ) are arranged, the moving block receiver being formed to move a block to be pressed, introduced with a loading device, into a compression position in front of the counter bar ( 3 ) having a die, characterized in that a shearing device ( 4 ) is provided for separating a butt remaining after the extrusion process, and the shearing device ( 4 ) is vertically and horizontally movable on the extrusion frame. The invention further relates to a method for separating a butt during extrusion and tube extrusion using an extrusion press or tube press according to the invention.
1. A method for separating a butt in extrusion and tube pressing using an extrusion or tube press having a counter housing, a die braced forward against the counter housing and having a rear face spaced in a rearward direction from and turned away from the counter housing, and a billet holder movable forward toward and rearward away from the rear face of the die, the method comprising the following steps:
pressing a workpiece forward from a starting position toward the billet holder past the rear face of the die and through the die against the counter housing while holding a shear in a rest position proximally forward of the rear face, above the die, but not above the billet holder,
thereafter retracting the billet holder rearward into the starting position spaced rearward from the rear face,
thereafter horizontally displacing the shear level with the rear face,
thereafter vertically displacing the shear across the rear face for shearing off a butt,
thereafter displacing the shear horizontally rearward away from the billet holder;
thereafter vertically retracting the shear above the die but not above the billet holder after shearing off the butt, and
thereafter horizontally displacing the shear back into the rest position.
2. The method according to claim 1 , wherein a horizontal displacement of at least 3 mm is performed after shearing off the butt.
3. The method according to claim 1 , further comprising the step of:
aligning a blade or a shearing plate of the shear parallel to the counter housing at least during the shearing operation.
4. The method according to claim 3 , wherein the blade or shearing plate of the shear is aligned parallel to the counter housing during the entire process.
5. The method defined in claim 1 , further comprising the step of:
moving the shear only parallel and perpendicular to a direction of displacement of the billet holder in straight-line motion.
6. The method defined in claim 5 , wherein a front face of the billet holder is of a greater dimension measured perpendicular to the direction of displacement than the rear face of the die.