Cutting Costs by Driving Down Resin Drying Time
Canam Manufactured Products Inc.
Surrey, BC
V4N 4C7
604-888-7699
http://www.speedryer.com/
For More PR Information,
Contact:Jim Neilson, CMP Inc.
PH: 604 888 7699
FAX: 604 888 5944
e-mail: speedryer@shaw.ca
The drying of hygroscopic resins has always been a problem for the injection molding industry, as added moisture can result in product defects. Since hygroscopic resins have a natural attraction to water molecules, they take up and retain water as soon as they are exposed to humid air. These resins include the partially hygroscopic such as ABS, acetal, acrylic, polycarbonate, PBT, LCP, and some TPOs, TPEs, and TPUs, and highly problematic difficult-to-dry materials such as bottle-grade PET and Nylon.
For many years, desiccant dryers have been the norm for resin drying, and facilities have had to live with drying times of 2 to 4 hours per load. However, in today’s highly competitive injection molding market, finding new methods to perform work faster and at less cost while still maintaining quality is paramount. Now, the application of new technologies can reduce resin drying times to 30 minutes or less. The results? Faster production start-up, increased throughput, and reduced energy costs.
In Search of a New Solution
“Very often, if we have to use a desiccating dryer, the mold will be all ready to go and they’ll still have to have the machine sit for another couple of hours waiting for the plastic to fully dry,” said Mike Torpey, VP and general manager of W.K. Hillquist Plastic Injection Molding of Hudson, NH. “It’s probably an additional hour’s time spent every time we change materials to clean the desiccating dryers, which means that every time we change, the press is not running an additional hour.”
Other traditional drying methods also fared badly with regard to drying times. Tyco Electronics, manufacturer of electronic connectors for the auto industry, uses injection molding in the manufacture of electronic connector housings. For its regrind process, Tyco was using conventional driers and regrind blenders. Not only was this method time-consuming — requiring 5 to 7 hours drying time — it was also ineffective at removing moisture.
Our regrind process was picking up moisture in the blending process, so it had to be re-dried using a conventional dryer,” said Michael Nordahl, Tyco’s chief engineer.
Both Tyco and W.K. Hillquist are now among the facilities using the Speedryer from Canam Manufactured Products, which brings hygroscopic resin drying times down to as little as 30 minutes.
“I would say on average we’ve saved 5 to 7 hours per load,” Nordahl says. “Not only are our initial start-ups faster, but each restart is easier too.”
W.K. Hillquist’s Mike Torpey has also found this technology extremely beneficial. “When we’re starting a new job, it certainly allows for us to typically get the jobs running at least a couple of hours ahead of time because we don’t have to pre-dry the material from 2 to 4 hours,” he said. “So on start-ups we definitely see a couple of hours’ savings each time we run the job, at least.”
Other Cost-Saving Benefits
The Speedryer uses rapid application of heat to increase the vapor pressure inside plastic pellets and to force entrapped moisture to the pellet surface. A counterflow of heated air strips the moisture from the pellet and transports it away into the atmosphere, leaving dry plastic.
Nordahl has also found this method to be far more effective as regards stress on material and moisture removal.
“The application of the Speedryer corrected our moisture problem, improving material degradation, and increased our processing window, particularly on nylons,” he said.
“We’ve basically tried many kinds of plastics with them and we’ve had very good success with most materials,” Torpey agreed.
Another benefit has been energy savings: this technology uses about 25% of the energy normally required for desiccant dryers. “They are extremely more energy-efficient than a desiccating dryer because of the lack of moving parts and blowers and big heater banks,” said Torpey. “The cost per hour to dry the plastic is very reasonable.”
The hopper dryers mount right on the feed throat, and Torpey has found the smaller footprint and reduction in mechanical complexity has meant easier maintenance.
“They’re small,” he reported. ‘We don’t have to have this monstrous dryer on the floor taking floor space; basically it mounts right on top of the machine. They are easy to set up on the machines and also easy to clean. They are very trouble-free running.
“On our bigger dryers, we could lose a blower motor and sometimes it takes us the better part of a week to get a new motor in,” Torpey added. “And they’re usually very expensive — probably a quarter the cost of a Speedryer just to get a motor replaced or a circuit board or something. We’ve found that the overall maintenance cost is very inexpensive.”
Another major factor in manufacturing is cost of machinery, and in this Torpey has found another advantage with the newer technology.
“The cost of those is less than half of the desiccating dryer,” he said. “It allows us to have more cash available to invest in other equipment as well.”
Along with other advances in injection molding such as electric molding machines and robotics, cutting down on drying time is allowing facilities to greatly increase operational efficiency, reduce bottom lines, and remain competitive.
By Bruce Boyers Bruce Boyers is a freelance writer based in Glendale, California
