For injection molding — as well as just about every plastic process — process cooling is very important for cycle time and part quality. Cooling sometimes seems like a last-horizon type of variable for a molding factory, witness all the talk about conformal cooling in the mold and the need to keep rigid control over part cooling. And the cooling water for the machinery, itself, must be tightly controlled.
For this month's Best Practices, we turn to medical molder Polymer Conversions Inc. in Orchard Park, N.Y., near Buffalo. Polymer Conversions partnered with Frigel North America Inc. for a whole new closed-loop system.
Back in 2012, Polymer Conversions was doing an expansion at its 60,500-square-foot plant, which includes Class 7 (10,000) and Class 8 (100,000) clean room areas for molding and assembly.
Now, any medical molder is going to have tight control of its processes. But Polymer Conversions wanted to:
• Gain more accurate temperature control, and have flexibility at each molding press.
• Continue to achieve optimum cycle times, while maintaining the highest possible quality of molded parts that can have complex part geometries and tight tolerances. (These parts could just help you stay alive.)
• Simplify the configuration of process cooling to boost efficiencies, as well as minimize maintenance time and costs.
• Cut its ecological “footprint.”
Polymer Conversions and Frigel conducted a complete analysis of the processor's cooling system, and decided to gradually replace its older and disparate equipment with an integrated solution suited for the molding operation.
Frigel makes closed-loop cooling equipment, using a series of piping and fans, like a car radiator or an air-cooled chiller. At Polymer Solutions, this closed-loop system replaced an open cooling tower.
The Frigel solution for Polymer Conversions was this:
• A total of 15 of Frigel's portable Microgel RCD combined chiller/temperature control units. The Microgels are positioned next to any number of the factory's 25 injection molding machines. The plant runs 24/7.
• Two Ecodry central coolers that supply cooling water to the Microgels.
• A microprocessor-based controller system with remote monitoring. That lets Frigel personnel to manage a wide range of system parameters, to run as efficiently as possible. It also simplifies routine maintenance.
Frigel North America, in East Dundee, Ill., is part of Frigel Firenze SpA, based in Florence, Italy. Frigel North America helped with design and planning, and handled installation.
The new closed-loop cooling system has helped Process Conversions control process cooling temperatures within plus or minus 3° F, vs. plus or minus 5° F with the old system. Frigel technology eliminated the need for multiple portable chillers and temperature control units for each press location. Polymer Conversions has virtually eliminated maintenance issues associated with the former system, and allowing zero discharge to the local municipal wastewater system.
The Frigel units supply consistently clean water to the injection presses year-round through the use of the Ecodry closed loop system — even in frigid, snow-slammed Buffalo. And they save as much as 95 percent in process cooling water compared to the old open-cooling tower setup, according to the companies.
Al Fosco, global marketing manager at Frigel North America, pointed out that water is becoming more precious around the world. And it takes 24 gallons of water to produce a pound of plastic, he said.
It's a case of water, water, everywhere — seeming abundance. But as we know from the drought in California last summer to the drinking water crisis in Flint, Mich., water — like every other natural resource — is not an infinite resource. It needs to be conserved.
Not to mention ever-higher water bills.
