DuPont Performance Polymers’ innovative in-mold hold pressure (IMHP) technology increases the productivity when semi-crystalline thermoplastics are processed by the injection molding technology.
The IMHP technology saves up to 30% of time in short overall cycle times or big shot volumes. The technology offers two dissimilar methods, both of them integrated inside the mold, for supplying hold pressure and the consequent supply of dosing molten material.
New In-Mold Hold Pressure technology from DuPont delivers significant time savings, based on material crystallinity and shot volume.
In the first method, a hydraulically operated piston that is incorporated into the mold’s movable side is dipped in a specially prepared and properly dosed melt cushion. On the other hand, the equivalent amount of melt volume is present in the hot runner on the mold’s stationary side. Then, a needle-valve-like system is used to press the molten material into the cavity. DuPont has tested and fine tuned both the methods, with a focus on reducing the extra space needed.
Ernst A. Poppe, who serves as DuPont Performance Polymers’ European Manager for Application and Processing Technology, stated that the company has carried out several trials with various semi-crystalline thermoplastic grades using injection molding technology at its Technical Center located in Meyrin, Switzerland, and demonstrated, depending on the manufacturing of standard bars utilized for the potential efficiency enhancements and tensile testing.
Poppe further said that IMHP technology is especially suitable for processing DuPont Delrin acetal resin that has a hold pressure time representing a larger proportion of its entire molding cycle time. The company also demonstrated that standard injection-molded samples manufactured by the IMHP technology had the same mechanical properties and dimensional stability.