The Sigmat 9000NT system runs on a processor?s main computer and supervises temperature zones, blending, width, thickness, pressure, and throughput on mono and coextrusion lines with up to eight layers. The system also generates alarm reports, administers recipe downloads, and allows an operator to monitor several departments and processes at once from computers in separate locations.
A central interface designed to run under WindowsNT enables the user to download and retrieve information from blenders, sensors, and controllers. The user interface consists of graphics that show the processes seen by the operator. These graphics automatically adjust to reflect the configuration of the specific installation. A touch-screen interface lets an operator intuitively navigate the system, or a conventional keyboard and trackball can be connected to the system keyport.
Reporting facilities track roll, order, shift, alarm reports, and material usage. The alarm report traces alarms to a specific distance into the roll, and identifies the time the alarm occurred, when it was cleared, and by whom.
Production problems, output efficiency, and finished product costs can all be monitored with the system. Information is stored in a standard CSV (comma-separated variable) format compatible with most standard spreadsheet programs. Standard roll and order report templates can be viewed in Excel or formatted by the user. The order report template calculates the total order cost of material, labor, and power costs per unit.
The Sigmat 9000NT uses standard protocols resident in the system library of most modern control units. Typical installations link to barrel temperature zones, die temperature zones, melt temperature and pressure, automatic material select manifold, power meter, winder tension, and blower controllers.
TSM Control Systems Inc., Atlanta, GA
All-electric press features wide platens, flexible design
With the capabilities of a 2000- to 2500-ton hydraulic plastic injection molding machine, the Ultima UN 1550 all-electric injection molding machine offers a wide platen equivalent to a 2000-ton hydraulic machine. This a-c servodriven, toggle-style electric molding machine is capable of molding large parts such as automotive instrument panels and door trim. Electric machines will reportedly reduce energy usage, give more accurate molding cycle control, shorten part cycle times, reduce clamping force, and lower scrap rates. They also offer a greater variety of molding applications including thin-wall molding because of more precise machine control. Eliminating hydraulic oil maintenance and disposal offers advantages for cleanroom molding.
Other benefits include a flexible design that easily incorporates new processes such as inmold coating. The machine?s constant pressure filling capability eliminates pressure spikes at cavity fill, allowing natural injection speed deceleration during cavity fill and a smooth transition from injection to pack. The machine has a clamping force of 1550 U.S. tons. The tiebar space is 72 by 59.4 inches with a 98-by-78-inch platen. Standard die height is 25.59 to 51.18 inches. Its dimensions are 559.17 inches long by 129.92 inches wide by 125.79 inches high with a weight of 180,400 lb.
Ube Machinery Inc.
Ann Arbor, MI
Vacuum tester evaluates containers
The VacTest, a tabletop vacuum tester, measures the vacuum resistance of rigid plastic containers. It enables an operator to test the quality of containers by determining the maximum level of vacuum that a container can withstand before it becomes distorted or fails.
Applications for the unit include quality testing of products on the production floor, incoming inspection of purchased containers, and evaluation of container designs in the development laboratory. The unit verifies the quality and performance capabilities of containers used for hot-fill and similar applications where containers are subject to distortion due to internal vacuum forces.
The VacTest is designed for simple operation and easy maintenance. A digital readout provides continuous vacuum data during the testing of a container, and the peak value is retained upon failure. Bottles with standard and widemouth finishes of up to 7 inches can be tested without fixture changes.
Thermoformers offer twin-sheet production
Twin-sheet R-Series thermoformers use two sheets of thermoplastic and are designed for economical high-volume, low-maintenance production. The first sheet is formed downward and held in the form by vacuum after the clamp frames are released. The second sheet is then rotated into the forming area and formed upward onto the top tool. Next, the two tools are brought together and squeezed. The heat already in the sheet bonds the two products together. The operation takes minutes, yielding a one-piece product with the attributes of two formings.
The R-Series thermoformers have a variable frequency drive form station and are available in three basic models. Each model comes in a variety of mold sizes and depth of draw. The thermoformers reportedly provide reduced cooling and increased production definition.
Brown Machine USA
Mold technology increases cavity count, cleaning system cuts downtime
Two new Micropitch 144-and 72-cavity preform molds from Husky are designed to increase cavity count in 300- and 600-ton machines. This is described as one of the most effective ways to increase output while reducing preform costs. Using the 144-cavity mold, system output reportedly increased by 50 percent vs. a 96-cavity, 600-ton conventional PET system. The 72-cavity system was said to show gains of 50 percent vs. conventional 48-cavity, 300-ton PET systems.
These molds use the Micropitch stack design, which accommodates preforms with thread finishes up to 30 mm in diameter. Options include a three-position takeoff plate, cooling technology, and optical part detection.
Cleaning high-cavity-count molds is traditionally a time-consuming process, and Husky and CAE Alpheus have teamed up to provide injection molders with a productivity-improving portable dry ice cleaning system that reportedly reduces mold downtime by as much as 80 percent.
Called Power DFX, the cleaning system uses fine particles of dry ice that blast through small venturi nozzles in a stream of compressed air. When the particles hit the mold surface they vaporize into CO2 gas, causing microscopic explosions that flush molding residues from the steel surface. This is said to have advantages over manual systems that use hazardous solvents and disposable wipes, and are more time consuming.
The cleaning system is designed to be quiet, easy to use, and works well in hard-to-reach areas. It can be used to clean resin residue from injection mold vents, degraded plastic material from hot runner manifolds, plastic accumulated on injection screws, and sticky residues on blowmolds.
Husky Injection Molding Systems Ltd.
Rancho Cucamonga, CA
By Design: K 2001: A designer's perspective
In this bimonthly column, Glenn Beall of Glenn Beall Plastics Ltd. (Libertyville, IL) shares his special perspective on issues important to design engineers and the molding industry.
I am now reflecting on my triennial pilgrimage to the mecca of the plastics industry. The K Show in Düsseldorf, Germany is the world's largest plastics event. There were 2885 exhibitors touting their latest and greatest products among 17 buildings totaling 1.6 million sq ft. The more than 230,000 attendees created an occasional traffic jam in the aisles, but the biggest crowds were in the injection molding buildings. For a product designer, K is like being a little kid in a toy store with his grandfather's credit card. So much to see and learn about. There is never enough time.
Processing Machinery Dominates
K is basically a plastic material and machinery extravaganza. Processing equipment dominates the show. The European orientation was noticeable. Europe has more solid waste legislation than the United States. Most of one large building was devoted to recycling equipment. Recycling equipment will become a growth market when the U.S. gets serious about its own mounting solid waste problems. When that happens the European suppliers, who have already developed their equipment, will have an advantage over North American machine manufacturers. Also, there was more molding of thermoset materials at K than at North American trade shows.
One interesting, new U.S. development that caught my attention was the two-material, sandwich molding machine introduced by Twinshot Technologies of Rifton, NY (see "Rediscovering, Unleashing the Value of Coinjection," December 2001 IMM, pp. 24-25). This unique process uses a standard single-barrel machine with a second screw inside of the standard screw. The two separate melt flow paths come together at the tip of the primary screw. Two-material molding is growing in usage. This is a good process for increasing recycled content. The ability to retrofit a standard molding machine with this special barrel and screws will allow more molders to enter this market with a much smaller upfront investment.
My overall impression of the processing equipment displays was that most everything was bigger, faster, and more fully automated. This confirms my belief that U.S. injection molders' reluctance to adopt robots is an invitation to another auction. (Click here for a report on automation at K.)
|If there was an exciting, totally new plastic material introduction, I missed it.|
The manufacturers of plastic materials were major exhibitors. They organized some of the largest and most elaborate displays. This was reassuring, as the major resin manufacturers have been conspicuously absent from recent North American trade shows.
The plastic material suppliers have always been my first stop at K. This is where they introduce their new resins. Equally important, they showcase all kinds of applications made with their materials. Many of these durable products are new and they provide an indication of what will be on store shelves in a few months.
Resins with very high specific gravity and significantly increased thermal and electrical conductivity were featured. An automobile side window molded in polycarbonate was on display. I can just imagine what the stylists will do with the shape of cars when injection molded windows become a reality. Every resin manufacturer was touting improved materials. But if there was an exciting, totally new plastic material introduction, I missed it.
The products actually being produced in the machinery halls are also enlightening. These items are international in scope, but European products dominate. European OEMs appear to be less reluctant to push styling and the use of color. Experience indicates that North American OEMs will pick up on these trends in a year or two.
Men love cars, and components for the transportation industry dominated the show. Electrical and medical parts vied with packaging applications for second place.
Insert, assembly, and two-color molding were everywhere. Sharply contrasting, bright colors were shown on office equipment. Translucent see-through colors were molded in several booths. Some of these products were two-color molded in contrasting cool, transparent shades and bold, opaque colors. Two-material, soft-touch products with an elastomer molded onto a rigid base still seem to be in vogue. One has to wonder how much longer these two styling trends will continue. My guess is that when the combination is functional, it will last forever.
An Office Molding Machine
Styling is also being pursued by many of the plastic processing machinery builders. The contemporary, clean-cut appearance of many of these machines has benefited from the input of an industrial designer. Many of these machines would look more at home in an office or laboratory than on the manufacturing floor. This is probably a trend that will continue.
A number of the exhibitors showed inmold painting and decorating. One of the most impressive applications was insert injection molding onto a painted or printed and decorated thermoformed part. One side of a robot's end-of-arm fixture picks up the thermoformed part and positions it in the cavity while the other side of the same fixture removes the molded parts from the core side. The process sounds involved, but it runs very efficiently. This technique allows the molder to use reprocessed material on the back side of the part.
The hiding of weldlines, flow marks, and the irregular appearance of a reinforced material are not new applications for inmold decorating, but it appears to be perfected to the point of commercial viability. Mobile phone housings and automobile body panels are now being produced by this technique. Packaging and toys can't be too far off. I have to believe that this technique has great potential. This could be a good niche or added-value market for a processor who has thermoforming and injection molding capabilities.
The K show, once again, convinced me that the concept of world-class products, where one design is suitable for the global market, is an intriguing idea, the time for which will never come. Each country has its own unique consumer preferences. Most European cars, grocery carts, and refrigerators are smaller than in the United States. All multinational OEMs would be well advised to send their product designers to the next K exposition in order to develop a much-needed international perspective.
During the three days that I spent at K, I encountered fewer Americans than in the past. I assume this is due to the economy and the terrorist attacks. However, I have lived through other scary times and other recessions; life and business go on. Those who invested in attending K are now in a better position to take advantage of the next upturn in business.
K is a very long, intellectually stimulating walk. The prospect of finding something exciting in the next exhibitor's stand masks the pain in your feet and helps keep you walking.
Molders Economic Index: Cautious signs point toward a recovery soon
Is the 17-month manufacturing recession close to an end? Many molders told us that in late November and all of December new orders for all types of molded products came in at a surprisingly strong rate.
Molders saw increased orders for computer and telecommunications parts, automotive components, and items for housing and appliances. Several equipment makers have reported an increase in orders for everything from basic injection molding machines to plant automation systems and auxiliary units.
How soon will injection molding return to growth? We still believe that it will take several months. Measurable signs of growth will not materialize until May or June. That's provided we are not hit with another national emergency. We have, somewhat cautiously, lifted growth targets for the end of 2002.
Overall Signs of Strength
What injection molders tell us is confirmed by other data. And the general media is touting a recovery soon.
The critical monthly Purchasing Manager's Index rose for a second straight month to 48.2 in December from 44.5 in November. The report showed factories faced the strongest flow of new orders since April 2000 and ramped up production even as they continued to shed unwanted inventories. In October the index hit a 10-year low of 39.8. A reading of less than 50 indicates manufacturingâ about one-sixth of overall U.S. economic activityâ is contracting. The index has held below that level since August 2000, making this the most severe manufacturing contraction since the 1990-1991 recession.
The New Orders Index rose to 54.9 in Decemberâ its highest since April 2000â from 48.8 in November. The Production Index pushed above the 50 mark to 50.6 from 47.1 in November; the Inventories Index fell to 37.7 from 37.9 in November.
In November durable goods showed signs of improvement. Excluding the volatile transportation categoryâ down sharply due to lower aircraft ordersâ durable-goods orders rose a solid 1.1 percent, the first back-to-back increase since November-December 1999. New orders for automobiles rose a strong 4.5 percent in November, on top of an 11 percent increase in October.
Other signs of growth came from housing, which saw little real contraction in 2001. Housing construction jumped 8.2 percent in November. Builders broke ground on a seasonally adjusted annual rate of 1.65 million housing units, an 8.2 percent increase over October's level, the Commerce Dept. reported in late December.
Overall construction spending rose .8 percent in November. This is of almost immediate benefit to molders making items such as pipe fittings, electrical components for lighting, appliances parts, and even furniture components. The Commerce Dept. reported that in November electrical equipment and household appliances saw orders increase by 2.6 percent, after a 4.5 percent gain in October.
Strong Automotive in 2002?
More molding operations are likely to move to Mexico soon. In January Toyota Motor Corp. chose a site outside Tijuana, Mexico for a new truck plant. Parts suppliers are encouraged to set up shop close to the assembly facility.
However, automotive may not be as strong in 2002 as it was in 2001. During 2001 a total of 17.18 million vehicles were sold in the U.S.â the second best year on record behind 17.4 million units sold in 2000 and ahead of 16.96 million in 1999.
But what may have hurt sales for the first part of 2002 were very aggressive sales campaigns late last year, offering all kinds of incentives including interest-free financing. Many molders are worried that this cannibalized sales for the first part of 2002.
Carmakers seem to agree, with massive job reductions planned by both Ford and General Motors. Still, numerous automotive molders saw increased orders in December and in the first week of January 2002. This was to rebuild severely depleted inventories. Yet, molders worry that their output will contract in the February-May period.
We hear from molders that key electronics marketsâ computers and telecommunicationsâ are showing signs of life with new orders up and quoting activity increasing.
The market research firm Dataquest Inc. in January reported that global telecommunications market revenue was on pace to reach $1.4 trillion in 2001, an 8 percent increase from 2000 revenue. The industry will continue to grow in 2002 with worldwide telecommunications revenue projected to reach $1.5 trillion.
Worldwide telecom equipment and infrastructure revenue is expected to reach $364.7 billion in 2001, down 4 percent from 2000 revenue of $381 billion. For 2002, Dataquest projects an improvement that will favor molders of low-tolerance precision parts used in telecommunications equipment.
Much of the quoting activity deals with entirely redesigned products. And several moldmakers in the United States, Canada, and Portugal have reported solid increases in orders.
What will drive growth in 2002 are redesigns. For instance, portable MP3 players will shrink in size but hold more songs. Mobile phones will double as handheld computers. Televisions will be bigger, sharper, and cheaper.
What this means for molders is more pressure to produce low-tolerance parts rapidly to support quickly shifting product introductions and relatively short life cycles. Molders with a high degree of automation and the ability to react quickly to market demands will stand to benefit the most.
Getting Tough on China
China's entry into the World Trade Organization will force injection molders there to start playing by the rules of international trade. We anticipate that this year will see several major anti-dumping suits filed against China.
In December 2001, in the first such move in North America, PPG Canada Inc. was told of plans by the Canadian Customs & Revenue Agency to initiate a dumping investigation of automotive replacement glass windshields from China. If dumping is found to cause injury to the Canadian industry, the imported Chinese windshields will be subject to an antidumping duty.
While this is glass, the same claim has been made by U.S. automotive parts molders for some time now about the growing volume of injection molded car parts from China. This is a development worth watching.
For a PDF version of the Economic Index table click here.
Agostino von Hassell of The Repton Group, New York, NY, prepares this index. Contact him at [email protected].
Production parts from prototype tools
Looking for a niche? Mercury Tool & Mold Inc. found one, producing highly engineered rapid tools for production parts. Kevin Moran, president of this Milford, CT-based mold engineering, moldmaking, and molding firm relies heavily on a high-speed machining center and a few small molding machines to do the job.
Mercury has invested $450,000 over the last six months, adding two Shinwa Seiki 75-ton injection molding presses, a company-wide computer network, and a Deckle Maho machining center.
Moran's primary customers are medical OEMs that often prefer hard prototype tooling due to the number of parts needed for testing and approvals. The company also serves the electronics and consumer product markets with prototype tooling, preproduction runs, and production molding.
In this high-speed, specialty environment, the Deckle Maho machining center is complemented by three seats of Cimatron CAD/CAM. The machining center has an 18,000-rpm spindle, which allows Mercury to cut both aluminum and electrodes extremely fast and accurately, Moran explains.
"This is one step up from urethane tools where you can only get 100 parts," Moran says, adding that his customers produce several thousand parts for first-generation components before moving on and building another tool for the next generation.
Mercury recently completed a mold for a medical part that contains numerous ribs. From design to completion the job took just three weeks. "This is an actual tool," stresses Moran. "They're getting a part very similar to a production-quality part in that the dimensions will be there, it will have fit and function, there's no flash, and we molded it in a custom color."
The customer didn't consider Mercury a prototype house, says Moran, but it needed production-quality parts in a prototype tool. "They're now on the second generation and recently purchased another tool for the program," he says.
Moran says that his decision to make the investment in high-speed technology to produce rapid prototype tooling is the result of pressure applied by offshore competitors. "We can't compete with China on labor-intensive production mold work, but the engineering and product development is staying here," he says. "We feel that's the way to go."
Mercury Tool & Mold Inc.
A new alliance promotes PIM to designers
IPIMA is the International Powder Injection Molding Alliance, a new promotional and marketing agency captive to the PIM industry. It pools the resources of U.S., European, and Asian PIM industry leaders to create greater global demand for the complex metal and ceramic components PIM can economically produce with a front-end pull-marketing campaign targeted at the design decision makers (DDM) who drive the business.
PIM has grown substantially over the last decade. But, according to the founder of the IPIMA, more than 80 percent of the potential market for an emerging technology like PIM lies beyond an adoption chasm--a chasm any new technology must cross as it moves beyond visionary early adopters (Figure 1).
Virtually all metal and ceramic parts today are designed to avoid PIM's biggest advantage, namely the ability to produce complex net-shape components. Traditional processes emphasize simplicity to reduce machining costs and long lead times. The DDM are conditioned to avoid complexity. PIM is fighting to change the status quo.
No single member in the PIM value chain has the resources to bridge the adoption chasm all on its own. Yet they all rely on the DDM to create complex PIM part designs and to stick to their guns as the design is scrutinized under the magnifying glass of the modern corporate review process. That's why the IPIMA's founder says the time is right for such an alliance.
Figure 1. IPIMA is a strategic alliance of PIM industry players who understand how to help emerging technologies cross the adoption chasm.
The goal of IPIMA is to change the prevailing mindset of the DDM and to inform them of the complexity advantage PIM provides. With its member firms, IPIMA will educate the DDM on the PIM process and the nature of the PIM value chain. Then it will assist the DDM in getting over the hurdles encountered as they attempt to gain approval for the use of PIM.
The alliance plans to accomplish its goals through the use of advertising and an information portal website (www.complexshape.net). Informational/sales support services and materials also will be provided, as will consultations and seminars.
IPIMA member companies can spend less energy on upfront sales activities, such as educating and persuading designers. The sales prospects IPIMA generates for its members reportedly will be more informed and better qualified.
Prior to founding IPIMA, Steve James was the executive vp and coo of Injectamax Corp. (Escondido, CA), a major MIM house. A career DDM himself, James says, "The DDM are busy people who use only what they understand. PIM technology astounds many of them. Our alliance will harness the latent potential of PIM and leave conventional technologies struggling to explain why they can't meet the demands of modern product design. The time has come to cross the chasm."
IMM's Plant Tour: Thriving on perfect vision
Everyone tells me I must have guts starting a business during a downturn," says Ron Ernsberger, president of 20/20 Custom Molded Plastics. "But in fact, we were too far along in our business plan to stop when the economy tanked. Molding machines have to be ordered 12 months in advance, and at the time we ordered, it appeared the economy knew no limits to growth."
Despite the worst downturn in what some experts say is 10, 20, or even (fill in the blank) years, Ernsberger, along with partners David Blosser, David Rupp, Jay Stuck, and Toby Ernsberger (son), persevered at the task of bringing a custom structural foam molding operation to life. Their efforts have not been in vain. The fledgling facility, opened in June of last year and situated amidst a 36-acre field, is comfortably busy and profitable.
Two 500-ton presses share one side of the plant with a new 1000-ton machine. A 45-ton overhead crane services the entire plant.
Likely to Succeed
Are there any factors that contributed to this plant's success? For one, the dynamics are different for structural foam than for traditional injection molding. "There aren't that many molders doing it, so there is less competition and market saturation," he says. "There are a lot of good injection molders, probably 60 within a 60-mile radius of us, but perhaps only a dozen custom structural foam molders in the whole country."
Another reason could be experience. Ernsberger has been molding plastics since 1965. He began in compression and injection molding, and then discovered the structural foam process in 1977. He proceeded to spend 22 years modifying two existing structural foam businesses and opening a third, building them into prosperous concerns. This is the first time that he and his partners started from a greenfield site. "I've done this three times before and learned from the experience each time. I believe we've structured this new business for success in just about every way possible. We want it to be the benchmark."
To those who would predict the demise of this process, Ernsberger offers another picture. For one, industry sales have tripled since 1985 on the strength of new applications. For another, he has always found customers for structural foam, and sees the process as advantageous during the current business doldrums. It uses less energy and resin per part, saves on tooling because it requires only aluminum molds rather than tool steel, and reduces production and per-piece costs.
Each platen contains holes that can be filled by nozzles, giving the process a great deal of flexibility.
|Long conveyor tables help the large parts molded in this 500-ton press to cool sufficiently before being boxed and shipped.|
|Programmable nozzle controls allow technicians to choose from eight sequences, or to program each nozzle individually.|
These aren't the only differences between structural foam molding (SFM) and traditional injection molding. SFM is a low-pressure process that incorporates nitrogen gas or another chemical blowing agent that is injected during the melting phase and dissolves in the molten resin. During resin injection, the gas expands to fill the mold with foam, pressing the plastic against the walls of the cavity so that the cells on the surface collapse to form a solid skin.
Part weight reduction can reach 20 percent, and because pressures are lower, sink marks are not an issue. SFM also handles large parts with ease, and imbues stiffness by increasing the thickness of the part's solid walls. Typical SFM products include returnable shipping pallets, carts, buckets, containers, window shutters, cabinets for IT equipment, in-ground filtration, and recreation equipment.
The injection phase for SFM is quite different from IM as well. Although the machines use an extruder, its design is different from the injection unit with which most molders are familiar. The extruder on SF machines consists of a screw-and-barrel unit that feeds a long manifold. Connected to this manifold are a large number of nozzles, placed strategically through one of a multitude of holes on the platen, that fill one or multiple molds arranged on the opposite side.
With two extruders, these presses can accommodate two different colored materials or two different resin types, producing several parts in one color or resin, and several in another. Each extruder can deliver up to 2800 lb of resin per hour, and shot sizes can reach up to 200 lb for a single part on a 1000-ton press.
The two orange extruders and accumulators on this mammoth machine can run up to 2800 lb/hr.
|An impressive 1000-tonner will give 20/20 the ability to mold a single part that weighs up to 200 lb.|
|Extruders feed material to a manifold, shown here, to which nozzles are then connected and installed at appropriate hole locations on the platen.|
Ernsberger and his partners had a clear idea of what they wanted to do with 20/20 before the first spadeful of dirt was turned over. For one, they believe in buying American, and have a policy of buying only domestic tooling and machines, one that began long before Sept. 11, 2001. The new facility continues a formula of using Maguire blenders and loaders with Uniloy and Milacron molding machines. "We built our former facility with new Uniloy machines and used Milacron IMMs. In five years, we didn't have two weeks of cumulative downtime from those machines," Ernsberger says.
Besides dependability, 20/20 relies on innovation to compete as a custom SF molder. "They [Milacron] have continually upgraded their product lines, and that's very important for a custom molder. We're different from captive, in-house molding operations in that we have to stay cutting edge. People come to us to prove out new designs and gain competitive advantages."
For instance, 20/20 recently worked with Kaymac, a South African injection molder, to prove out a mold and train Kaymac personnel on how to run a Uniloy 500-tonner. "Kaymac had just purchased a press identical to the one we had, and before it arrived, they wanted to become familiar with it," he says. "So we provided the training and invited Uniloy and Snyder Mold to attend the mold trials."
When he first started equipping the new facility Ernsberger looked for the same kind of Milacron IMMs he had used previously, but Milacron, in 1989, had stopped building the model he wanted. The machine combined a 375-ton frame with an extra-wide platen taken from a 500-ton machine. Ernsbergber searched the used machine markets and found two machines. When he went to Milacron to get them rebuilt he learned that the company also had a used machine in stock.
Ernsberger bought that machine as well and had Milacron do a complete remanufacture on all three. The machines were disassembled and cleaned, worn items were replaced, and each was fitted with the latest electronic controls and hydraulics. A modified nozzle allows the machines to do either structural foam molding or high-pressure injection molding for greater application versatility, while the extra-large platen exploits the large-part capabilities of structural foam molding. Machines have either 110- or 165-oz shot size capabilities.
When IMM arrived for this tour, 20/20 technicians were also installing a 1000-ton Uniloy machine with a superwide platen that has single-part capabilities of up to 200 lb. Two 500-ton Uniloys are up and running, and a third was due to be delivered soon. These seven machines and the associated areas needed to store and ship the large parts produced here will take up all of the 40,000 sq ft of floor space.
Up to six material components can be blended at the press using these weigh scale blenders.
|Molds are hung on this side of the superwide platen.|
|Flexibility of ejector placement on the back side of the moving platen contributes to the ability to run more molds simultaneously.|
|Each system in the plant has a backup, including nitrogen, chillers, cooling tower, and compressors.|
One of the 500-ton presses running at the time of our tour was producing four identical parts, each weighing almost 17 lb. Four molds were hung on the platen, and a bit of each mold hung out on the side. With SFM, however, this overhang is acceptable, thanks to the low pressures. Each mold uses four nozzles to fill each part, and each nozzle opens in a programmed sequence.
As with other custom molders, the advent of the PC and programmable controls has given 20/20 some high-tech answers to its challenges. For example, the timing of resin injection via multiple nozzles is critical to part quality. The opening and closing of nozzles is now programmable on all of its machines, along with how much material each nozzle will inject and how long the shot duration will be. On the 500-tonners, nozzle feed controls can be preprogrammed with one of eight different sequences, or each one can be individually programmed.
At 20/20, a state-of-the-art nitrogen system uses bulk nitrogen supplied to compressors at 6 psi, which then compresses the gas to 3900 psi for use in the extruders on the machines. Nitrogen is introduced into the melt at the third heating zone on the extruder, where it is mixed with the molten resin. This is a critical stage in SFM, and one that is closely monitored.
All of the systems in the plant have a backup so that the plant can continue running uninterrupted during any system failure. This includes the nitrogen compressor, air compressor, chiller, and cooling tower systems.
Up to six different material components can be loaded and blended at the presses for volumes that don't dictate compounding, thanks to weigh scale blenders and a materials handling system (both Maguire). These components can include the neat resin, colorant, regrind, calcium carbonate (a filler), and an additional chemical blowing agent.
With four silos built and four more to be added soon, 20/20 expects to have approximately 1 million lb of bulk material storage capacity. The silos are pneumatically loaded from trucks currently, but will soon be loaded from rail cars when a proposed rail siding is installed. The ability to store large amounts of material is critical, according to Ernsberger, who estimates that the plant uses 2400 lb of resin per hour per extruder.
Cycle times run from 80 seconds to 6 minutes at this facility, and any commodity resin either filled or unfilled can be molded via SFM. However, 20/20 has designed its machines for high throughput using PE and PS materials, so it generally sticks to these two resins.
|VITAL STATS |
20/20 Custom Molded Plastics Ltd., Holiday City, OH
Square footage: 40,000 on 36 acres; plans for a 30,000-sq-ft warehouse in spring 2002
20/20 Custom Molded Plastics Ltd.
Holiday City, OH