Time to Shed Some Light on Drying

It’s probably way past time for a clearer understanding of this essential process by most processors. In my 27+ years of plastics journalism, never have I come across a process that causes more consternation among processors than drying plastic pellets.

And, really, their problems with drying have nothing to do with any technological shortcoming. It’s not as if “the thing” isn’t working right. Quite the contrary, suppliers of dryers have advanced their technology to the same—if not greater—extent as any other equipment category. We’re seeing more in the way of user-friendly controls, automated self-regulation, energy savings, flexibility, and just about everything else, than ever before.

Yet so many processors have had a problem with drying for years. I’ve heard that not just from equipment suppliers, but from the processors themselves. One put it to me this way: “You can have the best dryer that money can buy and still be bad at drying.”

The problem with drying, I think, is more of a mindset. Nobody wants to be bothered with drying, but if you’re running hygroscopic resins you have to.  Lots of processors view drying as a necessarily evil, and getting them to think about it as seriously as some of their other processes can be challenging. Unlike, say, blending, which allows processors to develop formulations and recipes that improve the properties of their products and possibly the prices they can charge for them—no one makes money from drying. But you can certainly lose money by doing it wrong.

With those thoughts in mind, we bring you this supplement to the May issue of Plastics Technology, “Drying Done Right.” In it, you’ll find tips and advice from two of the industry’s foremost experts in materials and processing: Mike Sepe and John Bozzelli. To regular readers of Plastics Technology, these should be recognizable names: Mike authors our monthly Materials Know How column, while John writes our Injection Molding Know How column. We also have a feature story in which processors who know their stuff about drying share their knowledge.

Finally, this supplement concludes with another Bozzelli contribution: a handy drying cheat sheet consisting of a dozen tips (and a quiz to boot). You ought to think of running to your photocopier and posting this checklist on a bulletin board in your plant, or near every piece of drying equipment you have.

We’ve intended this supplement to be “evergreen.” Our goal was to present information that would be useful to you now as well as tomorrow, next month, and next year. We hope we’ve met this objective.

Happy drying.