the parting line between the stationary 34 a 34 and movable 34 b 34 moldhalf sides as an x y coordinate plane as mounted into the horizontal molding machine of fig1 then let us designate the z axis perpendicular to this x y plane and motions of the 34 b 34 mold partforming surface 31 traveling along this z axis are preferably driven by the motions of the injection molding machine 39 s movable platen as shown in fig1 which in turn operates under the control of the process controller a less preferred embodiment is to drive these equivalent motions with an auxillary hydraulic cylinder mounted within the moldset or onto one of the molding machine platens relative z axis motion of the b plate 12 with respect to b clamp plate 21 with the a plate 10 remaining stationary throughout therefore translates directly into a corresponding motion of the b side partforming surface 31 with respect to a side partforming surface 30 this relative z axis motion of the b plate 12 with respect to b clamp plate 21 is settably limited in its forward direction to the right side of fig1 by the movable platen having achieved full clamp lockup as shown in fig1 a when resilient member 13 is sufficiently compressed to allow the b plate 39 s rear surface 40 to seat onto b clamp plate 39 s forward surface 41 and settably limited in its rearward direction to the left side of fig1 when stripper.