A question recently came in regarding an older post about running high-temperature materials in normal machinery: High Temp Machinery
Question: We run high temp resin in newer electric presses. i do not believe our injection units were retrofitted with any special materials. the main resin put through our units is PAEK with 30% glass reinforcement, which is a tannish color. we have been experiencing "black streaks" on the part surfaces, and no one in house can seem to figure out the root cause. These streaks are usually dark brown, (despite the symptom name) and really seems to be burnt up resin at the edge of degradation to me... but whether or not our steel can handle the constant high heat cycles has been the main focus of attention. any thoughts from your end that could possibly help us out? we keep the rear zones at about 700*F on these jobs.
My Response: The most important thing to do first is to compare the actual melt temperature with the manufacturer's suggested temperature and verify the material is being melted properly. I have seen machines set at 750°F with a resulting melt temperature of only 675°F. In this example, we were able to increase the cooling time and significantly slow down the recovery speed to get the melt temp up to 710°F. This material was still 15° below the recommended temp, but acceptable parts were able to be produced for the while better heater bands were ordered.