Just because a machine is capable of processing at high temperatures, does not mean it is optimized for use at these temperatures. A machine which spends most of it’s time at high temperatures should be purchased and designed for that intent. A failure to do so will result in potential inefficiencies and premature equipment failure.
Situation: Recently I was working with a company who processes a large number of high-temperature materials. The manufacturer states the machine can operate at high temperatures without significant modifications, but it is not operating optimally. The melt temperature is consistently 30-50 degrees C below set point and the locking check ring is expanding more than the barrel causing a squealing to occur.
My Recommendations: If you occasionally run high temp materials, then a stock machine may be OK. If you are intending to process mostly high temp materials, especially at high speeds, you should consider a machine deigned for that application. Any thermal expansion differentials should be considered with respect to the materials & tolerances used for the screw, check ring, and barrel. The machine should also be fitted with heater bands designed for high temperature use to heat the material quickly and efficiently. There are many other considerations such as proper heat shield design, adequate nozzle heaters, and a pre-heating capable hopper which can improve the overall efficiency of the machine.
-Andy
Hi Andy,
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 noone in house can seem to figure out the root cause. These streaks are usually dark brown,(despite the sympton 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.
Thanks,
TOOLFANATIK
Hello,
We have addressed this in a new post.
-Andy