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 upper tool (11) comprising:
- a top base plate (4) and
- a plurality of plug moulds (5) arranged in an x-z array and connected in a translational manner to said top base plate (4) by means of driving rods (6) such that said plug moulds (5) are movable in a direction (y) perpendicular to a transport direction (x) of said preheated thin-gauge thermoplastic sheet (3);
- the lower tool (12) comprising:
- a plurality of cavities (8) configured to receive cavity moulds (8′) 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),
- the upper tool (11) and the lower tool (12) are being operable to simultaneously form a plurality of thin-gauge plastic products (2) in corresponding cavity moulds (8′) arranged inside the cavities (8) of said lower tool (12) in an x-z array and
- each of said supporting block (92) has a first substantially rectangular shaped zone (92a) in a vertical cross section through a y-z plane, said first zone (92a) extending perpendicularly from said base plate (91) over a distance (a1) calculated as 92-95% of the total height (a) of said supporting block (92) and the width (w) of the first zone (92a) is calculated as 10-15% of the total height (a) of said supporting block (92)
- characterized in that
- each of said supporting block (92) has a second substantially isosceles trapezoid shaped zone (92b), having a common symmetry axis with said first substantially rectangular shaped zone (92a) in the vertical cross section through said y-z plane perpendicular to said base plate (91), wherein said second substantially isosceles trapezoid shaped zone (92b) extends in continuation of said first zone (92a) over a distance (a2) calculated as 5-8% of the total height (a) of said supporting block (92), wherein the second zone (92b) has a bottom base in contact with the first zone (92a) and centered relative to said common symmetry axis, a top base and two legs of equal length between the top and bottom bases, and the width (w1) of the top base of said second zone (92b) is calculated as 2.5-5% of the total height (a) of said supporting block (92) and
- two vertical channels (81) are formed between at least two adjacent cavity moulds (8′) for accommodating a peripheral flange (B) of each of said thermoformed plastic products (2),
- such that said two vertical channels (81) are configured to alter, during forming of the plurality of thin-gauge plastic products (2), a thickness of said peripheral flange (B), to decrease from a medium thickness (t) of the thermoformed thin-gauge thermoplastic sheet (3) to a lesser thickness (t1).