A team from US Leisure did a study of barrel energy-saving technologies, examining energy savings and return on investment at the company's injection molding factory in Stanley.
The conclusion: For Stanely-based US Leisure, insulated barrel blankets are the most cost-effective choice for energy reduction, beating out induction and radiant barrel heating.
Stacy Wagoner, operations manager at US Leisure, said the company plans to buy more of the Uni-Vest barrel blankets from Chagrin Falls, Ohio-based IMS Co. this year and in 2011. Eventually, he wants to have the blankets on all injection presses at the Stanley operation. He declined to give the number of machines.
Reducing energy consumption is part of the firm's sustainability plan. US Leisure, a division of Keter Plastic Ltd. of Herzliya, Israel, molds polypropylene consumer goods such as outdoor furniture and garage and backyard storage products.
Wagoner pointed out that results are for US Leisure and its products, and that other molding plants with different processing conditions may get other results. “We set up a controlled study for our situation. The energy saved could vary significantly with each different alternative,” he said.
The study was conducted by US Leisure manufacturing engineers Jeremy Kipp and Shawn Caplette.
Wagoner said US Leisure's goal was to hold as many variables as constant as possible, since energy used by a given size of barrel is a result of the set temperature, type and color of the plastic, and cycle and recovery times.
The engineers used a single injection press with 1,800 tons of clamping force, running a single tool — and one color of resin — continuously during the study. In back-to-back, five-day periods, they ran first with conventional heater bands, followed by Uni-Vest barrel blankets, Xaloy Inc.'s nXheat induction-barrel heating, and the ServTek TCS radiant barrel heater sold by Milacron Inc.
Duke Energy supervised the installation of the meter to measure energy consumption.
According to the US Leisure study, the ServTek TCS generated the most energy savings, a reduction of 3.02 kilowatt-hours, followed by the barrel blanket at 2.38 kwh and nXheat at 2.09 kwh.
The barrel blanket won the US Leisure analysis of ROI payback. The blanket would pay for itself in 1.49 years, according to the study. The ServTek TCS had a 2.2-year payback, followed by the nXheat at 4.21 years.
US Leisure focused on the first two barrel zones on its test injection press, since the engineers determined those zones were responsible for more than 70 percent of the total energy consumed.