Material handling automation brings competitive advantage

Truly automating your plant involves more than robotics. If you really want to get lean and stay competitive, consider switching to an automated and centralized material handling system that not only reduces material waste, but impacts quality, yield, uptime, and labor costs.

Automation, one of the rallying cries heard among U.S. processors fighting to stay competitive, conjures up images of sprue pickers, part removal, and insert loading. Using robots to perform these functions makes sense, both economically and from a quality standpoint. Extend the concept one step further to material handling, say industry experts, if you want to thrive in today?s economic environment.

Adding a central materials handling system (CMS) is one potential for automation that plastics processors tend to neglect, as evidenced by the predominance of manual systems still in use in the industry. Gaylords continue to be the norm, with the "bucket brigade" as the least common denominator. Ask yourself if a worker on a ladder feeding material to a machine out of a bucket is safe and efficient. Then ask whether anyone using this method can expect to gain a competitive edge. The answers are obvious. As processors turn to lean manufacturing principles, the waste and inconsistency of this method become apparent.

Components of CMS have improved over the years, including the pneumatic delivery of bulk resin, blenders, dryers, and associated auxiliaries. Blenders, for instance, have become more accurate with touch-screen controls that enable two-way communication with a PC. Control systems are now available that can tie all of the equipment together, with easy access to and storage of all the data.

Those who have made the investment in CMS tell us they would never run their operations without it again. Examples of their successes, which follow, highlight the reasons for automating the materials handling function.

Attraction to CMS

When Willie and Bev Van Wyhe, owners of custom molder Vantec Inc. (Webster City, IA), decided to build a new facility six years ago, they did their homework by visiting some of the most efficient operations in the U.S. All of them featured an integrated CMS. What struck the Van Wyhe?s was not only the cost savings inherent in these systems, but also the impression that the shop floor made on potential customers. With the new facility, they were aiming to attract new customers, and the quality, consistency, and accuracy of an automated plant, thanks to a lack of gaylords and buckets, would help them to do that.

Six years later, after installing a complete system from Conair in the new plant, the Van Wyhe?s are planning an expansion that will nearly double the size of their facility. Again, they?re opting for the works in material handling automation. Why? "This was an investment that paid for itself in labor cost alone," says W. Van Wyhe. "Aside from that, our plant has been maxed out. Attracting new customers has been no problem, and keeping them has been easier as a result of these systems. I wouldn?t consider molding any other way."

In addition, the system at Vantec provides both accurate inventory and usage rates, while reducing costs and improving quality. He adds, "Our first priority is to provide quality products, so this was our major impetus. Improving consistency and accuracy has benefited our quality significantly. We also saw a major labor improvement. With the bucket brigade, there was always loss and error. With CMS, we have considerably reduced our labor rate. For all handling requirements, we now need only one person per shift. Formerly, this required several operators per shift."

Vantec?s latest CMS consists of pneumatic conveyors for 23 machines (55 to 720 tons, 20- to 150-lb throughput/hr), eight surge bins, six gravimetric batch weigh blenders, reclaim grinders, and 20 mobile dryer units. All auxiliaries are housed in a lower level, with material piped up to the presses through the floor. Grinders feed directly into weigh blenders for real-time usage.

Resin is stored in a warehouse on the main level, separate from the molding area, then transferred pneumatically from surge bins to the lower level. "With smaller tonnage machines," he says, "we couldn?t justify silos, so we continue to feed the surge bins from gaylords in the warehouse. However, with the expansion and larger tonnage machines, we?ll add silos to the system." Materials can go to any machine, dryer, or weigh blender at any location. The mobile dryer units can be repositioned, or parked, under the appropriate press within minutes. The Selectronic loader control system from Conair is currently being upgraded to an ILS control that interfaces with the facility?s Plantstar system.

According to Conair?s Joe Norco, the ILS is a distributed I/O (input/output) system with simplified wiring. Up to six operator panels around the plant allow production personnel to interface with the main system CPU. Initially, the system will control material handling pumps and loaders only, but the ILS is powerful enough to eventually allow managers to interface with the controllers on other auxiliary equipment, by monitoring and adjusting the settings on dryers, for instance.

Because Vantec molds for the appliance and consumer markets, it must maintain strict color requirements. One of the benefits of CMS includes the ability to control quality in these applications. "We now have the exact portions of color and regrind we?re required to have. We?ve eliminated quality issues associated with too little or too much colorant and regrind, and we?ve stopped paying more for colorant than we need, to eliminating overages," he explains.

Automating Solves Several Issues

KS Automotive, a growing, minority-owned custom molder in San Leandro, CA, had developed experience with CMS in its two plants and confirmed its benefits. As a Tier Two supplier of automotive parts for Nummi (a joint venture between GM and Toyota), the quality and consistency of automated materials handling were deemed essential. However, portions of the system at one plant could have been more optimum, including a central system that developed material plugs in the lines.

When the time came to redesign its second facility, according to Scott Hess of KS, the company had learned quite a bit, and plans included a better design for a new CMS. Hess and others provided a great deal of input on the system, and worked with Comet Automation to resolve several issues.

One of these, the aforementioned material plugs, were eliminated by adding line-clearing valves to the central weigh blenders. Another issue involving a consistency problem with color concentrate was eliminated by adding gravimetric weigh blenders.

In total, Comet supplied the following equipment for this installation: four silos, surge bins, honeycomb-design central dryers, hot-air dryers, central weigh blenders with central loaders, a custom regrind reclaim system, central loaders for molding machines, an Allen-Bradley SLC control, proportioning valves, a color feeder with three colors and an ABC switch for easy color changes, a custom mezzanine, and a large-pipe manifold system.

According to Hess, the redesign of the materials handling system was intended to streamline the process for cost reduction. "The results were dramatic," he says. "A process that used to be managed by four people was reduced to one person for an immediate first-year, bottom-line labor savings of $75,000. We also saw labor savings through reduction in the time needed to clean out the equipment."

By designing a custom mezzanine for the central weigh blenders, KS also freed up space on the plant floor for additional equipment.

Building a Flexible System

At the new Blackhawk Automotive Plastics facility in Mississauga, ON, a CMS installation just completed is being put to the test. Originally designed for 22 machines, the system will now have to handle another 23 presses that were recently installed. The system also needs to accommodate an additional 16 machines that will be added in the near future. According to Roy Zinner, maintenance manager, the additional machines are being added in response to an increase in business, and press sizes across the plant will range from 90 to 1800 tons.

When construction on the facility began last June, the decision was made to install a centralized system from Nucon-Wittmann, the Canadian division of Wittmann Inc. "CMS has been instrumental at all of our other facilities in providing consistency and quality at reduced cost, so it made sense to include it here," Zinner says. "For this plant, though, we incorporated greater flexibility because we foresaw the possibility that we?d have to expand quickly." Blackhawk also wanted to be able to handle a wider variety of materials and more colors at this facility.

Zinner and others at Blackhawk presented a list of needs to Nucon-Wittmann, which in turn designed the central drying and conveying system and provided 3-D drawings of the complete plant layout with all piping color-coded. "This was helpful to us, because we were able to quickly spot a few areas that needed to be changed based on our experience," he adds, "and this gave us the opportunity to fine-tune the physical layout."

This installation?which was handled by Nucon Wittmann, the materials handling division of Wittmann?uses both silos and gaylords. While the CMS routes material pneumatically from silos to high-volume presses, smaller-volume applications are loaded pneumatically at press side. PLC-based touch screens and a Siemens control help monitor material flow through the system. A central dryer system is also complemented by localized dryers from Wittmann. Currently, all weigh blenders are on presses, but Blackhawk is installing a centralized gravimetric batch system shortly. The system also has the ability to add real-time collection of regrind at a future date.

Another benefit to a centralized system that monitors how much material goes into each press, says Zinner, is that it can monitor any material waste by comparing material used to goods sold. "We mold roughly 4 to 5 million lb/year," he says, "and material waste is one cost we can?t afford. By monitoring usage, we gain assurances that we?re operating efficiently."