Patent ID: 7011777

Claim:
A method of securing a plastic film material within a mold comprising the steps of: a. placing a preform comprising the plastic film material within a cavity defined by first and second mold sections; b. placing a portion of said preform within an interface between said first and second mold sections; c. sizing a maximun gap of said interface between said first and second mold sections according to a m2 ( E 3 ) wherein m2=maximun plastic film thickness; and E=Elongation as a percentage of plastic film thickness; d. sizing a minimum gap of said interface between the first and second mold sections according to a relationship: m1 [ 2 ⁢ ( i L ) ] wherein mi=minimum thickness of the plastic film; L=compressive strenght of said plastic film; and L=injection pressure of plastic into said cavity; and e. sizing a width of said interface between said first and second mold sections according to a second relationship between said physical properties of said plastic film and process parameters.