I have been in the plastics industry for over 38 years and it never ceases to amaze me that when I visit Injection Molding processors, some of these folks just do not get hygroscopic resins very well. Most folks realize that they need to dry hygroscopic materials such as Sabic’s Polycarbonate or RTP’s Nylon 6/6.
However, there have been to many times where I have seen folks dry said materials in a dryer next to the machine and then take a five-gallon bucket and transfer the material manually from the bottom of the dyer to the top of an open hopper and maybe just maybe put a lid on that hopper.
This procedure defeats the purpose of drying the material. These types of material start to absorb moisture immediately after leaving the dryer. This is true of some materials more than others. You may achieve a good part, but there is a good chance that on a molecular level, you do not have the best part for your customer and there is a high probability of part failure.
When management invests in the equipment to process these types of resins, you must have the dryer on top of the machine’s feed throat. Or at the very least have it with a “just in time” loader pulling material from the bottom of the dryer, directly to the feed throat. Do not let it sit long enough to absorb moisture.
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