When setting up the most efficient plastics processing operation, careful consideration, design and implementation of auxiliary equipment that will support the entire production line can mean the difference between marginal profits and over-the-top results. Gone are the days when auxiliary equipment was treated as a mere “sidebar” to the overall molding or extruding operation. In today’s highly competitive plastics environment, auxiliary equipment provides customized solutions to maximize efficiencies in a wide range of areas. From reductions in energy costs, set-up times, maintenance, and waste to increases in output, safety, and overall production, auxiliary equipment continues to shape the profitability of processing operations large and small. Plastics Business had the opportunity to take a look at how auxiliary equipment is maximizing efficiencies for plastics processors nationwide. The following case studies and testimonials are prime examples of what ingenuity and careful design in auxiliary equipment can do to produce outstanding bottom-line results.
Material Handling Efficiencies
Butler Plastics Co., Marine City, Mich., is a smaller-sized molder specializing in short-run molding and light assembly for the automotive industry. With its nine molding machines running three shifts/day, five days/week, Butler makes several material changes per day and has found that the Conair ResinWorks® system has reduced downtime dramatically, resulting in substantial cost savings per week. The ResinWorks® system brings together drying, blending, and conveying technology as one package.
Addressing critical processing issues of plastics processors large and small, the system’s capabilities and features provide a host of efficiencies to Butler’s operation. ResinWorks® features include measured airflow to each hopper; easy access for clean-out; integrated airflow and temperature control; protection against over-drying; wireless source-to-destination protection; and high-performance modular conveying.
Although Conair uses a menu of standard components as a starting point, Butler’s ResinWorks® system, as with all Conair systems, was custom-configured to meet the company’s specific requirements – from the number of different materials being processed to the number of molding machines being serviced.
Core components including drying hoppers, desiccant dryers, blenders, vacuum pumps, and loaders are pre-assembled and delivered with material-handling controls, conveying pipes and valves, and other components to ensure precise resin drying, blending, and delivery. With conventional machine-side drying and material handling, it can take hours to make a simple resin change. Unnecessary downtime and material waste are costly, and there can be serious operator-safety issues as well.
On the other hand, with ResinWorks’® centralized drying and distribution, material changes are made faster because resins can be pre-dried and conveyed to processing machines quickly. According to Kevin Drummond, owner of Butler Plastics, “With our new system, we’ve been able to cut down tool changeovers considerably. What used to take one to two hours in material changeover now takes about 10 to 15 minutes.” Furthermore, the materials are now pre-dried through Butler’s centralized dryer system, which can load from twelve different locations. “Because the material is already dried, we save significant time – up to two hours – in the drying process alone,” stated Drummond.
Additionally, processors can remove individual dryers from beside or atop machines, which can cut labor costs dramatically and improve operator safety by eliminating manual handling of resin. Cleanliness of the production area also is improved with the ResinWorks® system. “The entire system is vacuum-based, so all the dust is drawn into dust collectors,” explained Drummond. “Before installing the system, material dust from the loading process was always a problem – but not anymore.”
Finally, the quality of the finished product can be improved with better control over drying and blending and with a greater reduction in the potential of contaminants. In the new and improved ResinWorks® system, which recently displayed at NPE 2006 in Chicago, many of the basic components have been reconfigured to dramatically reduce its footprint, thereby saving valuable manufacturing floor space.
For instance, the main electrical enclosure has been moved to the front of the system, making it easier to access and eliminating the need to leave space behind the sleds for service access. Likewise, individual drying air heaters have been moved out of the way and underneath the hoppers. Simplicity of operation is made possible through several innovations. Whenever the full supply of drying air is not required (when one or more hoppers are shut down for cleaning, for instance) a new bypass valve automatically diverts air back to the dryer so that only the right amount (CFM) of air is delivered to the operating drying hoppers.
New material distribution manifolds eliminate the often complicated tangle of material conveying hoses. Instead, a single hose is connected to a slide plate that is easily shifted back and forth to tap different material sources. Individual electrical disconnects for each hopper can be isolated electrically from the rest of the system so that service can be performed on one hopper while the others continue to operate normally. With all the system’s new features, Conair’s ResinWorks® system has afforded Butler Plastics a multitude of processing solutions that have proven to impact the company’s bottom line profits.
Lifetime Products, Inc., Clearfield, Utah, is a plastics processor specializing in the manufacture of residential basketball equipment, tables and chairs, and outdoor storage sheds. To maintain the continuous process of cooling machinery and tooling, which takes an enormous amount of power and refrigeration, Lifetime was operating four separate AEC water systems.
As the facility reached maximum capacity, Lifetime began looking for ways to run the plant more efficiently to conserve electricity. AEC worked with Lifetime to consolidate its four chiller systems and four cooling tower systems into one highly efficient cooling system for the 120,000 square foot plant. The combined systems require over 890 tons of refrigeration and 1300 tons of cooling tower capacity. Lifetime also would receive a financial benefit from Utah Power.
As one of the largest users of power in the state, it was to Lifetime’s advantage to streamline its power systems and conserve energy. In turn, this would alleviate the need for the power company to add additional infrastructure to support the power usage and could therefore, increase savings to Lifetime. Lifetime Products and AEC agreed to install a new cooling system, a modular pump tank system, and a motor control center incorporating a programmable logic controller (PLC) for data collection from sensors and output devices.
Bob Adams, general manager of Lifetime’s plastics plant, wanted to incorporate existing energy conservation programs in the plant, such as the standardization on Baldor high efficiency motors and upgrades of chiller technology to rotary compressor design. The ifm efector upgrade for system feedback was recommended to monitor process control. By applying ifm fluid sensors, Lifetime would receive consistent programmable set-up, alphanumeric displays, small housings, and analog and switching outputs.
The project began with AEC and Lifetime addressing the two main water systems needed to cool water for plastics processing: chilled water and cooling tower water. Consistency in temperature and even distribution in chiller water is extremely important for quality mold making. To accomplish this, Lifetime completed a multi-year program with AEC to replace semi-hermetic compressor chillers with efficient screw compressor technology. To conserve additional electricity, Lifetime installed an AEC Winter Kooler system. This system utilizes oversized evaporative cooling towers with variable frequency drive fans and heat exchangers instead of the usual fluid coolers. The PLC monitors wet bulb and may initiate the start sequence for the Winter Kooler towers at nearly 70 degrees F. As the Winter Kooler system comes on-line, the PLC monitors and disables the four 200 h.p. screw compressor chillers sequentially via feedback to a PID loop. Two 30 h.p. fans replace the four 200 h.p. screw compressor chillers, thereby saving over 900 amps per hour. For Lifetime, the dry, desert-like climate in Utah provides a natural cooling system almost nine months of the year. “It’s really irritating to run the chillers when it’s 20 degrees outside,” stated Lifetime’s Bob Adams. “When it’s cold outside, the PLC will turn off the chillers and run the AEC Winter Kooler.”
Other features of the complete chiller system include a PNI differential pressure monitoring system from ifm, which monitors the cleanliness of the heat exchangers on the tower side. Lifetime uses this sensor system as a preventative maintenance tool and can clean heat exchangers before an equipment failure occurs. ifm efector’s temperature monitors and remote sensing probes control fluid temperature feedback on chiller and tower systems. Additionally, process water is treated and sent through a filter to remove particulate matter before circulating through process equipment. Automatic purge and differential pressure alarms prevent the filters from clogging. By giving the chilling system a rest for several months out of the year, Lifetime prolongs the life of the chillers while still maintaining the same, consistent process temperature. Lifetime has been using the new cooling system since March of 2005. The energy efficient system has saved the company tens of thousands of dollars and has provided a comprehensive feedback control system for the plant.
From pickers, blenders, pullers, cutters, hoppers, and conveyor systems to sophisticated robotics and custom-designed systems utilizing a blend of technologies (such as those outlined in this article), auxiliary equipment of all shapes, sizes, and complexities continues to produce dramatic results in reducing costs, saving energy, improving safety, minimizing maintenance, and increasing bottom-line profits.
Conair is a global supplier of equipment for plastics processors, manufacturing heat-transfer systems and temperature-control equipment, resin-handling equipment, robots, size-reduction and scrap-reclaim machinery, and downstream extrusion systems for profiles and tubing. For more information on Conair’s complete line of equipment and capabilities, visit www.conairnet.com.
AEC, Inc. provides a broad range of auxiliary equipment and technical services for processors in a number of industries, including plastics. Products include, but are not limited to, cooling towers, portable chillers, air coolers, powder resin handling systems, size reduction/granulation, automated part and sprue removal, and a complete line of downstream extrusion equipment. For more information on AEC’s products or services, visit www.AECinternet.com.
ifm efector’s product line includes inductive, capacitive, cylinder position, photoelectric sensors, object valuation products, flow, pressure, temperature and level sensors, predictive maintenance sensors, AS-9i Bus systems, connectors, identification systems, and control systems for use in mobile machines. For complete information on ifm efector’s product line, visit www.ifmefector.com.