Abstract: The melt pressure transducer is preferably for use in pressure measurements associated with an injection molding machine, and is designed to be mounted inside a mold to measure cavity pressure directly. In addition to being small in size, the transducer is also adapted for high cycle life. The transducer utilizes an internal filler rod for temperature compensation and, also, to reduce liquid volume rather than a capillary. The strain gauges are secured to opposing flats of the housing to provide a pressure-ranged section. The housing is in the form of a thick-walled cylinder with the flats forming the sensitive areas. Further, a unique fill and seal technique is described for charging the transducer and, at the same time, pre-stressing the coupling diaphragm.