Düsseldorf, Germany — The best possible bottles at the coldest practical processing temperature.
Butler, Pa.-based Agr International Inc. says that's what PET bottle manufacturers can achieve with CrystalView, which is the third product in its Process Pilot measurement and management system.
The automated system not only monitors material distribution but company officials say it provides the means to run at the coldest possible temperature — “to the point where it is just right” — but not so cold that molecules break and a stress-whitening problem called pearlescence occurs.
With CrystalView, Agr says it's possible to reduce the preform processing temperature by as much as 10° C, which results in the best strength-to-weight ratio at a reduced cost. The cost reductions are related to materials, energy consumption (7 to 10 percent) and improved downstream efficiency for filling and processing operations.
The better performance comes in the form of increased shelf life (10 percent), increased top load (17 percent), reduced volume expansion or “creep” (38 percent), increased burst pressure (17 percent), and increased squeeze resistance (7 percent), David Dineff, AGR global product marketing director, said at K 2016.
“These are significant numbers. These are validated,” he added. “Those are the kind of things we saw just doing this step here.”
The first two steps in the Process Pilot line — called Controller and Profiler — measure every bottle to identify variations and control the blow molding machine to eliminate variation and provide consistent quality. They have been on the market for about 6 years and have been installed on about 200 systems, according to Agr.
The company says the third step, CrystalView, optimizes PET material properties using a colder process for a better bottle structure with maximum strength and minimum weight.
“You can have the best blow molder but still make a bad bottle,” Dineff said. “With our system you can have the worst blow molder and we can still help you make the best bottle.”
The CrystalView step was field tested and analyzed for about two years before it went to market a few months ago.
“We found that in a cold-mold process, the colder you blow that bottle, the better performance becomes,” said George Wolfe, Agr's chief technical officer. “As you lower the temperature of the process, the burst pressure, top load and shelf-life characteristics begin to improve. But there's a limit to how far you can go and that limit is where you create pearlescence.”
Several factors affect the processing temperature — from the environment around the blow molder to the preforms themselves, which can vary by lot depending on how and where they were stored inside or outside of the plant.
“These are all things you need to watch because they cause variations,” Dineff said. “What we're doing is looking for that variation.”
If the standard has moved off the baseline for any reason, the system responds.
“We ride that temperature change and whatever is going on around the blow molder, which is a huge oven with rows of long lamps and preforms spinning past them getting heated up and blown,” Wolfe said. “We control each lamp individually and the power of those lamps simultaneously and the pressure in the blowing station and the timing of the process. We're constantly adjusting all those knobs to keep everything where it's supposed to be. The operator just can't do that.”
Operators are multi-tasking, he added. At some plants they are loading preform gaylords into the dumping machine. They do mutation and quality checks like cutting-section weighing. They're unjamming the feed system to the blow molder. Sometimes they're taking care of labeling machines.
With the automated system focused on the structural integrity of the bottles, Wolfe said, “You can start taking material out of the bottle. You can make it lighter and less expensive and it flows better down the production line and it won't break in the trunk of your car if it's filled with a carbonated soft drink.”
Dineff added, “We've got customers making a billion bottles a year and if you can reduce material by a half gram, that's a lot of money. And it's forever. That's a nice savings and it's not a one-time savings.”
CrystalView is available as an add-on option for first-time buyers or a retrofit to systems currently in operation.
