Method and apparatus for nibbling cutouts with rectilinear and curvilinear contours by rotation of tooling with cutting surfaces of rectilinear and curvilinear contours and novel tooling therefor

In a punch press, the combination comprising:

• (a) a frame providing a base and a head spaced thereabove;
• (b) a ram assembly mounted on said head of said frame with a lower portion reciprocatable on said head for movement along a vertical axis towards and away from said base;
• (c) first drive means for reciprocating said lower portion of said ram assembly along said vertical axis;
• (d) a punch having a cutting edge portion extending across the lower end of said punch in a common plane and including at least two cutting edge surfaces A.sup.1 and A.sup.2 of different contour, the cutting surface A.sup.1 being arcuate and defined by the radius R.sup.1 and the cutting surface A.sup.2 being arcuate and defined by the radius R.sup.2, said arcuate surfaces A.sup.1 and A.sup.2 being non-parallel;
• (e) means supporting said punch for reciprocation with said lower portion of said ram assembly and for rotation about an axis substantially coaxial with said vertical axis of reciprocation of said ram assembly lower portion;
• (f) a die having an aperture therein cooperatively dimensioned and configured to receive said cutting edge portion of said punch;
• (g) means supporting said die in alignment with said punch and for rotation about an axis coaxial with said axis of rotation of said punch, said punch and die defining a workstation therebetween substantially in alignment with said vertical axis of reciprocation of said ram assembly lower portion;
• (h) second drive means for effecting simultaneous and equivalent rotation of said punch and said die about said axis of rotation at said workstation;
• (i) a work support table supported on said frame and extending about said die for supporting an associated workpiece thereon;
• (j) workpiece clamping and moving means supported on said frame for controlled movement of the associated workpiece along X and Y axes relative to said workstation and the vertical axis of reciprocation and the axis of rotation of said punch and die;
• (k) third drive means for said workpiece clamping and moving means;
• (1) control means for controlling the operation of said first and second drive means to effect reciprocation of said ram lower portion and for controlling the operation of said second drive means to effect rotation of said punch and die when said punch is spaced above said die, and for controlling said third drive means for said workpiece clamping and moving means to effect precise indexing of the associated workpiece relative to said workstation along said X and Y axes between strokes of the ram assembly to produce contiguous cutouts therein, said control means including program means for generating a series of signals to the operative drive means following a punching stroke (i) to index the indexing means and thereby an associated workpiece in a horizontal plane a predetermined distance relative to said workstation to a second position which distance is not greater than the operative punch cutting edge surface, (ii) to rotate the punch and die about said vertical axis at said workstation to change the orientation of said operative cutting edge surface relative to said X and Y axes, (iii) to reciprocate the ram assembly in said second position of said clamping and moving means, (iv) to index the clamping and moving means in a horizontal direction to a further indexed position a distance not greater than a second punch cutting edge surface, (v) to rotate the punch and die about said vertical axis at said workstation to orient the second punch cutting edge surface in operative position;
• (vi) to reciprocate said ram assembly in said further indexed position of said indexing means, said series of signals producing a multiplicity of the steps (i) through (vi) above for defining the contour of a large contoured cutout in an associated workpiece by the cutting action of at least said two cutting surfaces and portions of the periphery of the cutout by rotated positions of at least one of said cutting surfaces, whereby the angular orientation of a cutting edge surface may be varied to approximate closely that desired contour for a large contoured cutout in the workpieces and cutting edge surfaces of different contours may be rotated into the contouring position.