Abstract: An apparatus and associated method for embossing at least one fold line in a substantially rigid plastic material for use in collapsible folding box with angle windows is disclosed, and the apparatus has a roll of plastic material, a heating zone for heating a length of the roll fed plastic material, an embossing zone located downstream of the heating zone for forming at least one fold line in the heated plastic material, a punching zone for intermittently forming cutout portions in the plastic material, a takeup device for creating a variable length slack in the plastic material for providing the continuous movement of the plastic material through the heating zone and the embossing zone and the intermittent movement of the plastic material through the punching zone, a cross-cutter to cut the plastic material at the punched holes, a suction roll to convey the cut plastic material for connection to a glue-coated cardboard box blank.