IMM's Plant Tour:

If you were to ask most custom molders to drop 70 percent of their business, the most polite response would likely be disbelief. But that is exactly what Webster Plastics did between 1989 and 1992. "Going after every job is a '70s mentality," says president Vern Dewitt, "and in today's environment, it's also a great way to go out of business."

Webster's about-face began with deciding who their key customers were and investing in the people and equipment that would give those customers what they wanted. A general lack of knowledge about plastics at the OEMs Webster wanted to serve meant bringing engineering expertise in-house. Also, most target customers were interested in more of a partnership than a traditional supplier relationship, so Webster had to equip its plant to produce subassemblies and ship parts just-in-time.

Seven years after the change, the redefined strategy is paying dividends. Last year, custom molding operations moved to a new 75,000-sq-ft facility that functions on a workcell concept. During IMM's recent tour of the new plant, we found numerous examples of cutting-edge designs along with manufacturing systems developed around customer needs. Let's take a look inside this engineering marvel.

Customer Criteria
To qualify for Webster's key customer program, manufacturers need to meet a few general benchmarks. They must be involved in a growing industry or hold a market strength position. Financial stability is also required. Finally, Webster seeks out customers who need their expertise to bring products to market.

According to Dewitt, targeting these businesses is an important part of the company's growth. "The combination of this type of customer with our talents spells success," he says, "so our initial efforts are focused on finding them."

Sales reps make the early forays, at times uncovering potential customers who are unaware there is an opportunity to reduce costs and improve product quality by switching from metal to plastic. "We've discovered customers who weren't even looking for a molder that had numerous opportunities," says Dewitt.

Once a sales contact determines Webster can help, he or she turns the account over to a project leader. These are engineers who specialize in new application development, materials technologies, and plastic part design. They essentially become part of the customer's marketing and product development efforts, looking at cost improvements, proposing new designs, and assisting with computer-aided analysis and material testing.

An office area next to the molding operation houses four engineering teams who support project leaders and key customers. Webster dedicates up to five customers with active programs to each team. They are divided by market segments-automotive, IT, consumer, and industrial-and consist of manufacturing, quality, process, and tooling engineers.

Customers still deal with a single contact, the project leader, but the teams may become their engineering, purchasing, marketing, and quality departments. "We handle the tough metal-to-plastics conversions," says Dewitt, "so, in essence, we don't really sell plastic parts anymore. We sell design engineering and manufacturing services."

Shop Floor Specifics
Our tour begins with a stop at the process monitoring system. Joe Buonocore, plant manager, believes the plant's Mattec system is like the instrument panel on a car. "You could probably drive without one," he says, "but you may be going too fast or running on empty. Without appropriate feedback, there is no way to tell. With the yield effectiveness number, which takes into account cavitation, cycle times, and rejects, you can get an excellent picture of productivity."

Outputs from the system are available at each of three workcells, so if mold or water temperatures are too high, for instance, operators can troubleshoot. "If the cause of increased temperatures is out of their control," says Buonocore, "operators can start an engineering investigation." Senior process engineers offer another level of expertise, and operators can discuss problems with them or ask them to troubleshoot.

In fact, workcells are manned by well-trained operators who can handle much of the daily production without interference. Webster calls the system "focused cell manufacturing," and it involves placing a three-person team in charge of each 15-press workcell. The team runs the workcell as its own business, setting up machines, starting up manufacturing, inspecting, weighing, packing, and labeling parts. "They follow a template," Buonocore explains, "but add their own creative input as required. Each team has a mold technician, a process quality technician, and materials handling specialist."

To make this system work, Webster makes sure team members are updated on yields, quality levels, and other productivity measures. "They have all the inputs needed to run the business and to determine if they are meeting goals," he adds.

Webster is also involved in a more sophisticated use of its process monitoring system using Design of Experiments (DOE) methods. Certain machines are equipped with external pressure transducers and linear potentiometers, allowing senior process engineers to establish limits for different molding parameters through DOE.

Working with Mattec, Webster has identified key phases and critical machine settings to establish boundaries and optimize processing. In some cases, they have set up an alarm with a diverting mechanism such as a robot or chute to separate parts made under less-than-optimum conditions.

In the next 18 months, Webster plans to implement this system for all of its part numbers. It is time-consuming, but Buonocore feels it will be well worth the trouble. "DOE has to involve all cavities, so it can take longer than expected when one cavity is down. However, if we establish the process firmly and alarm it, we'll have no more tweaking or shift change variations on quality. It will make things black and white."

He cautions molders who are beginning this process to start with a capable machine. "We tested machines for two years to ensure their baseline operation was sufficient." Using a Hunkar portable machine analyzer, Webster got profiles of all of its presses. Once the vital signs were recorded, they were compared to industry data to see how well machines were responding. Surprisingly, some of the older equipment classified higher than newer machinery.

All of the 44 presses located on the molding floor are fed automatically by a newly installed Motan materials handling system. The Van Dorn and Demag molding machines (and one Newbury) are programmed to call for a certain amount and type of material. The pneumatic lines send these pellets into a small hopper for each cycle, then the system regrinds sprues and runners, sending them to a mezzanine at the back of the shop floor.

Once on the mezzanine, fines are separated and regrind is stored in a drying hopper. When a job requires regrind, the system mixes it together with virgin resin in an established proportion and sends it to the appropriate press.

Webster also has five materials silos outside the plant to store truckload quantities. "Materials are 55 percent of our cost," says Buonocore, "so we invested in the pneumatic system to help keep those costs under control. It reduces material changeover, spillage, and contamination. We've spent some time training our employees to use the system, and we have an in-house certification program and written testing for materials handling and process people."

Projects, Not Parts
Automotive Tier Ones and OEMs are among Webster's customers, and they have made full use of the engineering expertise offered. "We approached a major OEM who was using die-cast aluminum to manufacture an accumulator piston for transmissions," recalls Buonocore. "After die-casting, the ID had to be machined. We redesigned the part using a 65 percent mineral-filled PPS, saving them the extra step and associated costs."

Molding PPS parts requires a higher mold temperature-about 275F-so the mold is oil heated. The injection unit and granulators are coated for wear resistance because of the high filler content. Tooling wear resistance is also critical because production rates are so high that Webster can't afford excessive down-time for tooling maintenance.

Another engineering feat for a Tier One supplier involved the conversion of a metal windshield wiper pivot housing to glass-filled acetal. The part has critical dimensions, with thick and thin sections, ribs, and bosses. Webster designers were able to engineer parts and molds to accommodate acetal's shrinkage while still producing high-quality parts.

One of the largest jobs Webster has undertaken involves a partnership with Sentry Safe Group in nearby Rochester. Sentry's former all-steel safes were losing market share to competitors from Asia, but modifying the steel designs to meet customer tastes was cost prohibitive, according to Sentry.

Enter Webster, who helped to develop a new line of fire-resistant safes for the consumer and small business markets. "We started with a blank sheet of paper," said Dewitt. "We re-thought every process from design and materials to assembly and marketing." To reduce cost, the team converted liners, door panels, back covers, door covers, escutcheon plates, and accessory parts from steel to high-impact polystyrene (HIPS) resin. Sentry itself attributes the change to helping it re-establish a leading industry position with 80 percent market share. Production costs were reduced by one third while overall product quality increased.

The outer shell of the new safe is still made from welded, stamped steel while a cement insulation fills the gap between this outer steel shell and the inner polystyrene liner. To meet UL requirements, the safe withstands exposure to temperatures up to 1850F and protects the contents inside for up to two hours.

Webster chose HIPS (495F from BASF) resin for its toughness and flow, allowing easier processing with high stiffness and good heat resistance. Also, resin purity and consistency were a plus, according to Buonocore. "Safe components must be molded to tight tolerances, and we run automated equipment 24 hours a day, seven days per week, so we can't have operators adjusting the process for material variations."

Partnering with an OEM means relying on its own suppliers, so Webster chooses vendors as carefully as it selects customers. "What impressed us is that BASF showed the same interest in us as we show in Sentry," said Dewitt. "They were willing to go the extra mile for our business."

All Sentry parts are molded in workcell #1. The production for several different sizes of liners consists of one 700-ton and two 1000-ton presses. A beam-mounted robot removes parts from the mold and places them on a conveyor that allows for cooling each liner before it reaches the operator. Operators remove sprues manually, then load the liners in cartons after inspecting them for quality.

Production is scheduled on a JIT basis with Webster shipping six to eight truckloads per day, seven days a week. Although liners are installed at Sentry's facility, Webster does pad printing for the dial and various subassembly work before shipping. Sentry forecasts its requirements in advance, but there are also faxes sent at noon requesting additional parts by 7 a.m. the next day. Each safe uses about 10 lb of plastic, and annual production volumes are 500,000 safes.