A progammable, dynamically adjustable die stamping apparatus for die-stamping of cardboard blanks used in production of packaging trays is disclosed. The apparatus includes a dimensionally adjsutable die having a plurality of separate movable parts each coupled to threaded adjustment rods and drive motors; a programmable control is coupled to the drive equipment and can selectively adjust and lock the die parts to conform the die to any one of a plurality of cardboard blank formats. Plural air-operated lockable jacks coupled to movable members of a stamp are also provided, and the jacks operate to automatically adjust the stamp to conform to the selected dimensions of the die. The apparatus can accept plural magazines of cardboard blanks and a plurality of different blanks supplied successively; under program control, the apparatus can automatically change the dimensions of the die and stamp to conform to the desired dimensions of the finished tray.