A multi-cavity mould (1) for a thermoforming machine used in the process of high-volume, continuous thermoforming of a plurality of thin-gauge plastic products (2) from a preheated thin-gauge thermoplastic sheet (3) comprising an upper tool (11) and a lower tool (12) arranged in a cooperating manner; the lower tool (12) comprising a plurality of cavities (8) in which cavity moulds (8) are placed and a plurality of base plates (91) from which a plurality of supporting blocks (92) extend perpendicularly over a predetermined total height (a), situated between adjacent cavities (8), each of said supporting block (92) has a stepped profile comprising three substantially rectangular shaped zones (92a, 92b, 92c) and a fourth substantially isosceles trapezoid shaped zone (92d) in a vertical cross section, having a common symmetry axis.