Extrusion calibrator with insert plates

Abstract

An extrusion calibrating apparatus connectable to external sources of cooling water and vacuum, and usable to calibrate the exterior profile of a hollow thermal plastic extrusion. The apparatus includes lower and upper cover plates each having a pair of vacuum manifolds therein, the lower cover plate being fixedly attachable to a stationary support. The apparatus further includes lower and upper vacuum plates each having a plurality of vacuum slots extending between a lower and an upper side thereof and in communication with a corresponding vacuum manifold. Each of the vacuum plates also has supply and return water channels providing communication between spaced-apart interior supply and return ports on an inward side thereof. A heat-conducting calibrating insert is removably positioned within an interior chamber between the vacuum plates with lower and upper sides in face-to-face juxtaposition with corresponding inward sides of the vacuum plates. The insert has a calibrating aperture and a plurality of vacuum slots extending between the lower and upper sides thereof and communicating with the calibrating aperture, and the vacuum slots of the vacuum plates. The vacuum slots are defined by spaced-apart removable pairs of insert plates received in insert plate apertures in the insert. The lower and upper sides of the insert each have a water channel which communicates with a corresponding pair of the vacuum plate supply and return ports.