Plant Tour: Chasing perfection: A standout facility opens its doors

When have you toured a molding facility that features live potted plants . . . on the shop floor? Delphi Connection Systems’ newest addition in Vienna, OH, unveiled earlier this year, not only started as a “greenfield” project, but it also has “greenscaping” in the center of the molding area. What allows this level of interior design is a nearly cleanroom environment, complete with only all-electric presses, plantwide climate control for process stability, an extensive automated material handling system, and automatic guided vehicles (AGVs) to ferry part containers. And that’s only the tip of the iceberg. Intrigued? Let’s not waste any time getting this tour started.

From the Ground Up

Delphi’s Vienna Injection Molding Center began as the second phase of an extensive effort to focus on three major core competencies at its Ohio operations—injection molding, cable production, and metal stamping. Phase one saw the opening of a new IM plant in Cortland, OH four years ago. Taking their cues from the best practices in place at the first facility—practices based on the Delphi Manufacturing System—developers of the Vienna plant sought to go beyond the award-winning Cortland’s benchmarks.

“The Cortland plant is now the template for all Delphi Packard Electric facilities because it struck new ground in terms of lean manufacturing, increased output to more than a billion parts, cut scrap by 68%, and reduced tool changeover times by 75%,” says John Sefcik, Delphi Packard’s director of U.S. operations. “But we sought to redefine benchmarks with the second operation here. Our goals were quality, delivery, and manufacturing efficiency with an emphasis on flexibility.”

Designing and engineering the Vienna facility from the ground up was a huge advantage, according to Greg Pachol, supervisor of molding engineering projects. “We conducted a worldwide search for emerging innovations in various industries, regardless of whether or not the technology was being used in plastics processing, and then selected the ones that made sense.” Ohio governor Bob Taft, who attended the facility’s opening ceremonies to receive thanks for a $5 million state loan and $450,000 in grants, agreed that the cutting-edge facility is exactly what Ohio's manufacturing sector needs.

Improvements beyond the Cortland plant, an admittedly tough act to follow, include an installation and ramp-up finished five months earlier than predicted; more parts, resins, and volume handled with fewer people, inventory, and floor space; greener operations; faster cycle times with greater accuracy and consistency; a higher degree of error-proofing and real-time data availability; and the integration of in-house direct-ship capability and inventory management.

Going Green

With 120 production presses on the shop floor and four debug presses in the engineering lab, the Vienna facility has the capacity to precisely generate 1.4 billion parts per year. Half of the machines are dedicated to polypropylene and polystyrene parts, while the other half run nylon and other high-temperature plastics. Every one of those IM machines is a Milacron/Fanuc Roboshot Si-B electric, a choice made with a great deal of thought.

“We thoroughly investigated the options,” Sefcik says, “and the electrics won because they offered investment savings, faster cycle times, greater repeatability, reduced operating costs, quality improvement, less energy consumption, and environmental benefits.”

With 50% to 60% greater energy efficiency than hydraulics, according to Milacron, the Roboshots make it a bit easier to be green. Using the electric presses reduced the plant’s projected energy consumption by 55%, and saved the company $1.7 million in capital investment by eliminating the need for added utility infrastructure and machine cooling. Costs for hydraulic system maintenance, including more than 50 tons of hazardous cleaning solution waste, were also eliminated.

Cycle times and repeatability were also key to the decision. Greg Cowan, general manufacturing supervisor at Vienna, says, “Cycle times with these presses are reduced by 16% over hydraulic machines, and injection lag time is cut to a fraction of a second using Delphi’s high-speed picker technology to remove runners. Accuracy and repeatability are inherently higher, because the electric machines respond better to control commands and don’t vary over time because of fluid heating or compression.”

Milacron confirms that this was Delphi Connection Systems’ first experience with electric machines, and that each one has been modified to the company’s requirements. Custom electrical and water supply connections helped accelerate the installation speed, and also allow for machines to be interchanged as plant layout needs change. Says Karlheinz Bourdon, Milacron’s VP of machinery technology, “Not only was this our largest quantity order ever, but this is likely the world’s largest all-electric molding plant.”

On top of the green switch to electric machines, Delphi’s newest facility also features precise temperature and humidity control for process stability. The nearly cleanroom environment is maintained with a slight positive-pressure ventilation system that limits incoming dust and dirt.

Material Matters

At the heart of the Delphi Manufacturing System is an intense focus on lean principles such as waste elimination and simplified flow of materials. Both goals are addressed by a centralized material handling system designed by Delphi and Novatec that relies on 16 miles of piping and supplies more than 70% of materials automatically. Capable of sending up to 32 materials to any of the machines simultaneously, the system also includes closed loop automatic regrind handling.

Tom Blackburn, senior project engineer, explains that efficient material handling is viewed as a value-added function at Vienna, not just a process cost from which waste must be removed. “In addition to getting the right material to the press on time, we must also properly condition it. Too-dry, too-wet, and contaminated materials all cause quality issues.”

Materials are received in one of several bulk silos, or in sealed aluminum returnable containers, and then sent to surge bins or sealed hoppers in the raw material room. Here, the system provides for continuous processing of blended closed loop regrind and virgin resin, plus offline batch blending using gravimetric and batch blenders from Novatec. To maintain consistent production, the system ensures that each machine receives the same blend. Portable dryers in this area also handle lower-volume resin drying.

On the shop floor, two regional material handling areas each supply 60 machines. On the nylon and high-temp side, Region 1, material is dried in 16 separate hoppers with heater blowers, and then conveyed via pneumatic lines on a just-in-time basis. Each press has a single incoming material line so that materials can be changed on the fly without endangering contamination.

The second region, supplying the polystyrene and polypropylene materials, is reserved for blending since these materials do not require drying.

In total, the system conveys, blends, and dries more than 90 compounds and supplies the 124 IM machines with line purge and dry-air conveying, all in a limited space. Accidental conveying of the wrong material is prevented by an RF scan system that requires operators to scan and match bar codes on material, machine, and tool before the molding cycle can begin.

Error Proofing

Built into each process at the Vienna facility are various checks and balances, such as the RF scan procedure, designed to eliminate error. For starters, the plant runs on a “zero blocked cavity” policy to ensure consistent, efficient production. Getting to that goal requires that a thorough PM schedule for tooling be in place.

It also means that processing parameters, once set, are not changed. In the process engineering lab, materials are evaluated and initial mold trials performed. Two other operations, however, are at the core of the error-proofing system: process evaluation and training.

John George, process engineer, explains the critical nature of both functions. “We are using equipment identical to the shop floor—two 55-tonners, a 110, and a 165. We perform an engineering evaluation, and determine what we call the ‘Golden Recipe,’ which encompasses all process parameters. Once these are set, operators at the press download specific part numbers and receive the recipe. This ensures that there are no changes at the press.”

Unlike most molding environments, where process parameters need periodic adjustments, the climate control and electric presses make it possible for Delphi’s machines to run the Golden Recipe with no modifications. The result is greater consistency and less scrap. At capacity utilization rates of greater than 95%, production maintains Six Sigma levels.

Underlying this and other information exchanges throughout the plant is an Ethernet system based on Microsoft.Net for Manufacturing. It enables real-time monitoring of order entry, material requirements, tooling changeovers, production runs, and shipment labeling. It also maintains traceability, allowing Delphi to identify which containers hold parts molded from a specific shipment of resin.

Perhaps the most “gee-whiz” aspect of the communications system involves 11 AGVs that maneuver around the plant using 7000 magnets embedded in the floor. Molding machines count the number of good parts produced, and when that number reaches a preset limit, the operator is notified that the finished goods container is full. After press-side inspection, the operator pushes a button to generate a unique tracking label with serial number and destination. The Ethernet system then sends a message back to the workcell’s printer, which prints the label and generates a call to the AGV to retrieve the full bin.

AGVs (from Frog Navigation Systems) navigate their way to specific workcells based on a priority system. Full containers are slipped onto the unit, and an empty container is unloaded for further production. On the return trip, the vehicle unloads the labeled finished goods container onto a conveyor that feeds the shipping and packout area of the plant, and then picks up more empty containers. The Frogs, as they are affectionately called, also stop periodically at one of several stations to recharge themselves.