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K '98: The future of injection molding

For eight days in Dusseldorf, the world came to see what the future holds-more and better automation, more purpose-built machinery, more electrics, and more options than you ever dreamed possible. Here is Part I of our report.

Anyone doubting the prophecy of Milacron's Harold J. Faig around the time of NPE'94 should have been at K'98. Four years ago, Faig said we were about to witness the dawn of a new age in injection molding-the Electric Age. Ladies and gentlemen, the new age has arrived. In fact, some say the future has arrived ahead of schedule.

Electrics and Hybrids
Faig's words rang through the halls of the K'98 show where all-electrics were put through their paces, molding parts for existing markets, like medical pipettes and connectors; molding parts for exciting new markets, like DVDs and Smartcards; and molding parts for markets that have yet to be realized, like microcomponents for surgically implanted hearing aids.

The machinery makers that have all-electric machines were talking them up. Those that don't were talking them down. Regardless, the impact of all-electrics can no longer be ignored, and, as Faig said, the molding business will never again be the same.

A week prior to K'98, sources from Milacron's Elektron Technologies business unit hosted a SRO technology seminar in Ohio. They told their guests they predict 70 percent of all new molding machines under 1600 tons from Europe, Japan, and North America will be all-electric in less than 10 years' time. They say electric machine technology (EMT) will soon evolve into a business as large as hydraulic molding machines and eventually become the global standard.

Better net efficiencies, reduced maintenance, and environmental friendliness are among the major factors Milacron sources say are driving EMT growth. One Elektron Technologies source said he expected two-thirds of the major machinery OEMs exhibiting at K'98 to exhibit EMT. Milacron alone had five all-electrics on display.

At the show, a spokesperson for Nissei, the first company to field a servomotor-driven, all-electric machine in 1983, told IMM that about 20 percent of its molding machine production is now all-electric, and the majority of inquiries received are for servo-driven presses. They are mostly coming from larger molders driven by environmental concerns. Nissei says the operational performance of electrics and hydraulics today are almost the same, but electrics clearly win out when it comes to lower running costs.

Figure 1. Demag Ergotech's Elexis is a new hybrid design, using a servo-driven clamp as well as a servo-driven screw. A 220-ton model was demonstrated at K.

This source at Nissei believes most hydraulic machines will eventually be replaced by all-electrics except for special types of molding jobs, such as those requiring ultra-high-speed injection. Economies of scale will reduce the price of all-electrics. Speaking of cost, he says hybrid machines actually cost more to build than all-electrics today. Yet the hybrid, or partially electric machines, could be found on almost every machine builder's stand, usually in the form of electrically-driven feedscrews to provide constant plastification to shorten cycles while cutting the molder's energy costs. Demag Ergotech clearly moved the hybrid concept to a new level with the new-design, servo-driven clamp in the Elexis Series (Figure 1). There is a servo-driven screw for continuous plastification like virtually all the hybrids. However, the Elexis servo-driven clamp and several other engineering features take aim at some of the limits of the all-electric machines themselves. In this clamp, the servomotor energy, which is rotary, is converted to linear force via a patented hydrostatic gear with no significant loss of efficiency. This ensures precision and fast clamp movement.

Despite the growing popularity of all-electrics, many may find some jobs are better served by hybrids and hydraulics over time, and their popularity may swing back and forth. The Nissei source compares the impact of the introduction of all-electrics to the introduction of the reciprocating screw. Most OEMs jumped on the RS bandwagon, but today many are finding some jobs, like thin-walling, are better served by two-stage "hybrid" injection units, and, in applications like micromolding, by plungers. Meanwhile, four of the seven presses Nissei demonstrated at K'98 were all-electrics.

The all-electrics are multiplying. Toshiba showed its first all-electric, as did Engel, an all-electric tiebarless machine. Bodini Presse of Italy put a 120-ton model of the new Eledrive all-electric on the corner of their stand to attract attention. It did. Bodini also has a 150-ton machine and will shortly add 70- and 90-ton models. The machines use five brushless motors to power all the axes of motion in the machine. The Moog control system on the machine has software specifically created to take advantage of the electric machine's capabilities.

Since introducing its first all-electric machine in 1984, Fanuc has shipped 7500 units. That is 4600 in its home market of Japan, 1470 in North America, 1000 in Asia, and 430 in Europe. Company sources say they originally expected the electric age of molding machines would begin in 2000, joking that they are way ahead of schedule. They expect the protocols adopted at the COP3 environmental congress held last year in Kyoto, Japan and a growing push to ISO 14000 compliance to further accelerate the growth of energy efficient, environmentally-friendly EMT.

Figure 2. All-electric technology extends even to rubber molding, as evidenced by this new vertical design by Rucks of Germany.

Fanuc sources say the current price of their Roboshot machines is nearly half the price of their originals. Still, all-electrics generally cost 25 to 30 percent more than hydraulic machines though they've been found to have a very quick ROI. Company sources believe in 10 years time Roboshot prices must be lower than those for hydraulics, adding, "Otherwise we have no future."

Developments continue. Ube and Niigata are teaming up to build large tonnage, all-electric, a-c servomotordriven presses starting at 350 tons. A 650-ton all-electric will be available in 1999. Work has already begun on an 850-ton model, and a 1300-ton all-electric will be built in the very near future, according to an Ube source. Ferromatik, the leading manufacturer of electric machines, showed the first two-color/component machine without hydraulics. And lest we forget, Battenfeld's Microsystem 50 production cell for microscopic parts is totally servo-electric driven. Need any more proof of how things are changing? Try this one. Rucks Maschinenbau of Glauchau, Germany introduced a prototype of the world's first all-electric rubber molding press, a vertical 800-kN (88-ton) machine with FIFO injection. It brings all the performance and environmental advantages of all-electrics over to molding elastomers (Figure 2).

At K'98, one hot trend certainly was in evidence: all-electric optical media molding machines. Ferromatik, JSW, Toyo, and Fanuc all showed servomolding machines for disks. Battenfeld and others showed all-electrics for medical molding, another hot ticket. Boy Machines introduced an electric pump drive motor that allows synchronous cycle phasing for faster cycles, reduced energy consumption, and lower noise (Figure 3). Suppliers of hydraulically driven machines are getting on board.

Application-Specific Machines
K'98 proved the words "application specific" are now applicable in every segment of the injection molding business. Walk onto the stand of a machine maker, robotics supplier, materials handling specialist, and in particular, a materials supplier or compounder, and the first subject for discussion is what you are molding, and we mean exactly what you are molding: for what market, how, with what machinery and material, and so forth. On the machinery side, it is easy to see the machines built specifically for PET preforms, optical disks, or Smartcards. Look further and you find machines for making LSR medical parts under cleanroom conditions or integrated production cells for microscopic parts.

Figure 3. Boy's electric pump drive motor allows synchronous cycle phasing for faster cycles, reduced energy consumption, and lower noise. Figure 4. Post-mold cooling results in significant cycle reductions on Husky's G-Series equipped with CoolJet technology. The water-cooled takeoff plate optimizes coolant flow and prevents crystallinity penetration.

Robotics, parts handling, assembly, decorating-in or out of the mold-whatever you need, there is probably a system being built for specific applications or for just one specific application, depending on the volume. This trend, according to many marketers, will not only continue but probably increase. Naturally, the highest volume applications will get the most attention. Witness the machinery (and materials) rolled out to support the booming sales of PET preforms.

PET Preform Molding Machines
It is getting crowded in the PET preform supply chain. Netstal wowed the crowds with its new system while Krauss-Maffei and Arburg bowed-in with vertical preform molding systems. However, Husky, considered by most to be the major player in the global PET preform market, continues to raise the bar. At K'98, it introduced a patent-pending, internal, post mold cooling system, trademarked "CoolJet," that is designed to cut cycle times by some 15 percent over previous Husky robot-based takeout systems (Figure 4). The system combines Husky's patented multiposition water-cooled takeout plate with another servodriven plate with pins.

The pins are driven into the molded preforms on the take-off plate and deliver cool, compressed air that optimizes coolant flow in and around the gate, neck finishes, and thicker sections of the preform bodies. The CoolJet plate is then extracted before the takeout plate rotates 90 deg to release the cooled preforms onto a conveyor. Improved cooling prevents crystallinity penetration while reducing cycles. CoolJet technology is now standard on Husky's latest robotized G-Series PET preform systems.

Husky also introduced an economical new Index machine for lower-volume preform production and start-ups, perhaps in less developed areas of the world.

Right across the aisle, Chen Hsong Machinery demonstrated its new Chen-PET turnkey system built around its 380-ton Jetmaster molding machine with closed loop injection. The system includes the machine, valve-gated hot runner molds up to 48 cavities, preform removal, and all the necessary auxiliaries. The 12-cavity mold on show ran at 17-second cycles to the 450 ppm Coke spec for AA content. Chen Hsong sources told us a complete system sells for $300,000 or less.

Netstal's new PET Line 96, with its custom-designed extraction/cooling/unloading robot system moving preforms across the top of the machine, stopped a lot of traffic and started a lot of talk at K'98 (Figure 5). Its production rates range from about 24,000/hr at a 16-second cycle to about 36,000/hr at a 9-second cycle with cycle times dependent on design, size, weight, and thickness of the preform. The machine at the show was making a 23.4g preform with a 2.7-mm wall in a 9.5-second cycle.

BM Biraghi of Monza, Italy stopped many K'98 visitors with its new-technology, 48-cavity PET preform production system. According to Silvio Tavecchia, manager of Biraghi's PET Division, although the system gets high productivity from short cycles, it is also making a very high quality, stable preform with a low AA level. A key to this is the patented post-cooling station system that cools preforms from the inside and the outside while they remain in the male side of the mold for three cycles.

Spanish machine manufacturer Mateu & Solè has a new PET preform system, though they did not have enough space to show it at K'98. It is sold as a complete system with a mold built by Zygo of Canada. A blowing system from French builder Sidel can also be included. The M&S system is a 16-cavity unit with an output of 3000 bottles/hr and the capacity to make preforms/bottles from .5- to 2.5-liter capacity. Price for a complete system is $869,000, which M&S says is about half of what some other companies charge for a system with similar capacity.

Figure 5. This new PET preform molder from Netstal stopped K visitors with its custom-designed robotic extraction/cooling/unloading system, molding a 23.4g preform with a 2.7-mm wall in a 9.5-second cycle. Figure 6. Demag demonstrated the versatility of its modular "Multi" injection unit packaging by insert molding this bottle opener in Wacker LSR and nylon-12 in a single Ewikon hot/cold runner, rotary-platen Elmet mold run in a 1100-kN (120-ton) Demag Ergotech press.

In the Indian supplier pavilion, sources from DGP Windsor India Ltd. (formerly Klockner Windsor India Ltd.) told IMM they intend to introduce their new globally sourced PETLine system at a tradeshow in Mumbai this December. It will feature a 300-ton DGP Windsor PET 2.5K machine equipped with PLC controls, a special injection system, and ABB variable-speed PowerSaver pumping. A Piovan dryer and a 16-cavity Zygo hot runner mold will be included, as will a Taiwanese chiller. Also, the system will include a preform conveyor and a Spanish-built, reheat stretch blowmolding machine with U.S.-built blowmolds. Capacities will range up to 2400 bottles/hr for 1.5-liter bottles to about 800 bottles/hr for 5-liter bottles. Prices have yet to be determined.

Multicomponent Molding
One of the hottest multicomponent molding trends in evidence at K'98 was the molding of an elastomeric material, like LSR or TPE, on engineering plastics, like PC or nylon. For example, it was one of the top research projects of The Institut für Kunststoffverabeitung (IKV) of Aachen, Germany. The IKV molded LSR/PA parts in its K'98 booth on a specially equipped press from Arburg running a rotary platen mold from Braun.

The molded part, designed by IKV in conjunction with Arburg, Braun, and its other partners in the research project, including silicone supplier Wacker, proved such high-performance, soft-touch parts could be done in a single operation without any adhesive or any intermediate steps to ensure a good bond. The bond was achieved through proper material selection, part design, and process parameters. See another example in Figure 6.

Netstal demonstrated multicomponent molding of automotive ventilation system adjustment wheels in a molding system built up around its SynErgy 600 machine with L-configured injection units. The 2 + 2 cavity mold, from Weber of Dillenburg, Germany, featured two discrete hot runner systems, one for each material. Parts were removed by a floorspace-saving, beam-mounted, articulating-arm robot. The Sycap machine controller featured an OS2 operating system working with Netstal's own DSP firmware to provide, among other things, real time animated tracing of both setpoint profile curves with actual curves.

Demag, Arburg, Billion, and Battenfeld were among those showing their latest in multicomponent molding. Dr. Boy demonstrated small parts multicomponent molding. And sources at Ettlinger discussed using up to three of their Direct Injection Molding injection units on their new Hot Set machine for multicomponent micromolding.

In-mold Decorating
BASF/Senoplast, Bayer/Battenfeld, and Kurz all came to K with innovative insert molding techniques aimed at eliminating the need to paint plastic parts and improving ease of processing. Many of these developments have grown out of automotive OEM customers interested in plastic panels but unwilling to invest $300 million plus in new paint lines. Also, with painted panels, the paint process accounts for 60 to 70 percent of the total part cost. Environmentally, molded-in-color panels are also much friendlier.

Paintless film molding, or PFM, for automotive body panels and exterior trim is the product of a joint effort between BASF, Senoplast, Röhm, and Engel (Figure 7). The process begins with a three-layer film coextruded by Senoplast and called Senotop in-mold film. It contains a top PMMA (Plexiglas) layer, a middle colored PMMA layer, and a base layer of ASA (Luran S). This film is then thermoformed and trimmed, placed robotically into the mold, and backfilled with PC/PBT or PC/ABS on an Engel Duo two-platen machine designed for simultaneous injection and compression. With a maximum film width of 1450 mm and a greater stretching ratio than previous painted films, large parts are a viable option for PFM, according to Senoplast. Although a variation of PFM is used to mold the roof for Smart, the group is actively looking for project partners.

Figure 7. Paint-free body panels are the goal for this insert molding process developed by BASF, Senoplast, Engel, and Röhm. The PFM process uses a coextruded, colored film layer backmolded with ABS or PC/PBT on an Engel injection-compression press. Figure 8. Battenfeld, working together with materials supplier Bayer and moldmaker Zimmermann Formenbau, demonstrated in-mold decoration of automotive bumpers using a fully automated hinterspritzen technology for printed films they have developed. Battenfeld's hydraulic, two-stage mold closing system in its HM series machine is a key to the process. By the way, although it featured a radically downsized footprint, the 3000-ton HM used in this demo still was the largest-tonnage molding machine at K'98.

Bayer and Battenfeld also collaborated on an in-mold decorating process for a demonstration bumper fascia (Figure 8). In this process, a printed and thermoformed film is placed in the mold as PBT or PC/ABS is injected behind it. Simultaneously, a TPU sealing gasket is molded in place. A transparent PC window for lighting can also be molded at the same time because all necessary injection units are mounted directly on the mold. For the demo part, Bayer provided the materials, Battenfeld supplied a modular HM machine, and Zimmermann designed the 42-ton mold with additional injection units.

Kurz takes an automotive interior approach to insert molding with its relatively new process. The company supplies hot stamping foils applied to a film substrate such as ABS, PMMA, PP, or PC to selected thermoformers, who then vacuum thermoform and trim the pieces to the shape of the final part. Molders receive the insert, then backmold with a compatible resin. What makes this process stand out from simple in-mold decorating is that it can handle extreme 3-D surfaces at less cost than the only alternative, cubic printing. Kurz believes the trend toward more colorful, stylized vehicle interiors will make this process attractive.

One of the most interesting in-mold decorating applications was at Krauss-Maffei where a Beck Automation cell delivered film for a 2-gal tub in the mold in 11-second cycles. The pre-printed film started flat, stacked next to the press. A robot arm pulled one sheet of film a few inches to a cylinder mounted on a separate robot arm next to the mold. With the edge of the sheet attached, the cylinder rotated, wrapping the film around the cylinder in the shape required for the mold. When the previous cycle finished, the cylinder entered the mold and slid the film into the cavity; the other side of the arm, meanwhile, pulled the finished part off the core and handed it off to another stacking robot outside the press.

Low-Pressure Molding
Whether it is with structural foam, gas assist, or backmolding for in-mold decoration, low-pressure molding was a ubiquitous technological trend at K'98. Engel, Krauss-Maffei, Hettinga, Uniloy Milacron, and Arburg were among the suppliers demonstrating their latest low-pressure solutions (Figure 9).

Ube Machinery introduced a versatile and inexpensive low-pressure molding/in-mold lamination system trademarked Dieprest. Sold as an option for new Ube machines with Humma S controllers, or as a retrofit, Dieprest adds clamp sensors and control logic to standard machines with low-pressure control to allow three different modes of in-mold lamination at the flick of a switch. It handles foam inserts for automotive interior parts like door trim and glovebox doors, fabric inserts for interior trim, and printed "paint-film" inserts for automotive exteriors.

There's no cycle-time sacrifice. Also, users can switch the Dieprest system off to do conventional molding. They need not be locked into expensive special-purpose machinery or unconventional molds. The software even helps in guiding users through setup, and it automatically recalculates molding recipes on-the-fly for repeatable quality production. Dieprest is available across Ube's entire line of machines, from 350 to 2500 tons and beyond.

Most machine manufacturers have gone to two-platen designs for machines larger than 600 to 800 tons during the past few years with one conspicuous exception. Battenfeld resolutely stayed with its three-platen design. Now it's been improved. The redesigned HM Series (300 to 4500 tons), seen for the first time at K'98, responds to an important selling point for two-platens: shorter machine length. The newly shortened HM is equal or close to the length of similar tonnage two-platens, says Battenfeld, and sometimes even shorter. Depending on clamp size, a new HM will be up to 80 inches shorter than the previous design.

Figure 9. Krauss-Maffei demonstrated in-mold lamination with its new Decoform system. Designed for the production of high-quality, one-shot, automotive interior trim, pre-cut and preheated fabrics were robotically loaded into a Swiss-built mold from Kaufmann Corp., a hinterspritzen specialist. Figure 10. Crowds surrounded Rolla AG's Microsystem 50 at the Battenfeld booth, trying to catch a glimpse of the tiny gears it molded, inspected, and applied to a reel of tape for future handling.

Mectronics of Oslo, Norway, a licensee and representative of Hettinga's Helga gas-assist process, helped its customer, RFSU Rehab AB of Stockholm, use the productivity-enhancing ability of the process to create large, clear-span gas channels in manufacturing innovative new personal care products for the elderly and infirm. One is a comfortably contoured, lightweight, but structurally sound bathboard in recyclable PP. The other is a molded wheelchair designed for easy adjustments and disassembly. Mectronics also represents the variable-speed Power Miser drive system for molding machines out of Oslo.

Micromolding Machines
Underlining the recent growth and high expectations for micro-molding, that is, molding parts weighing a gram or two or tenths or hundredths of a gram, K'98 had a much larger number of machines, molds, and materials related to micro applications than at any previous show. Purpose-built machines and self-contained complete production cells have made their debut, and the adapter kits for small machines are multiplying. Moldmakers with the know-how to make tools for tiny parts were making sure visitors knew it. The new production technology is aimed at being able to make even smaller, yet very precise, parts than are being made today.

The prevailing opinion is that this market could grow even more rapidly than current ambitious projections. Experts refer to the fact that designers creating small communication devices, medical machinery, surgical implants, and a variety of handheld, palmtop, shirt-pocket devices that we will not be able to live without are just now seeing the potential for injection molding micro-sized parts. That means more products will be coming soon that call for micromolded parts. Of course, this may not be the greatest thing that ever happened to material suppliers, who will be asked to supply material that conforms to mind-numbing specifications, only to receive an order for 1000 lb . . . every three months.

Battenfeld's Microsystem 50, previously covered in IMM (Oct. 1998), is a specially built production cell that does not look like a conventional injection machine, and it is not a traditional injection system but a plasticizing screw feeding a shooting chamber whose contents are sent into the mold by a plunger (Figure 10). It also has a turntable mold for continuous production, a visual quality system that will QC every little part, a packaging system that delivers the micro parts on strips for automated assembly, and very intricate application-specific robotics all inside a small-footprint cabinet that maintains cleanroom conditions. Battenfeld is aiming initially at applications in watchmaking, medical equipment, and electrical/electronics, including MIM and PIM. Packaging the green parts in trays ready for the sintering oven, without handling, could be a strong appeal.

Professor Helmut Detter of the Technical University of Vienna managed the original project that resulted in the development of Battenfeld's micromolding system. Dr. Detter believes micromolding will have a shorter incubation period and faster growth into different market applications than the integrated circuit. He predicts integration of microparts and microcomponents into existing products will reach 50 percent by 2025. What he says is necessary for such growth and for even further growth is better education; more dynamic, innovative cooperation between different companies in different fields; and more government-sponsored technology transfers. Swiss molder/moldmaker Rolla AG, a leading global supplier of precision gears to the watch industry, owned one of the three Battenfeld micromolding systems in use at K'98. It wowed the crowds, molding and packaging acetal gears weighing only .0008g.

Dr. Boy has always specialized in small injection systems; however, its microsystem is identified as a "concept machine." The company projects the microsystems market growing from the current approximate $21 billion annually to about $45 billion in the year 2002. It sees most of the coming growth fueled by applications in automotive sensors, fiberoptic communication networks, medical science, and microbiology.

The Boy 12A Micro concept system is based on the Boy 12M that has been in the market for about a year, but the Micro has a totally new injection unit. A needle in the screw eliminates problems with bypasses and dead corners in plasticizing units with a downstream plunger. A relatively large screw with a specific geometry eliminates the feed problems common to smaller screws. The screw seals the melt chamber after plastification, eliminating the inaccuracies of sealing a non-return valve. The needle injection uses the first-in, first-out principle to avoid damaging heat-sensitive materials with overly long dwell times. The maximum shot volume of the machine at K'98 was only 2 cu cm, and further reductions in volume are planned.

Next year, Demag intends to extend the range of its Ergotech series of modular molding machines to include not only a 20,000-kN (2200-ton) press, but also a 150-kN (about 15-ton) hydraulic machine for micromolding.

Figure 11. Need to compound your own specialty material? This Krauss-Maffei machine has a piggyback compounding extruder that was compounding talc and PP just before the material was fed to the injection cylinder.

The Offbeat
Krauss-Maffei surprised the crowds at K'98 with an unusual, cost-saving molding system concept that combined injection molding and compounding all-in-one. Mounted piggy-back on the machine's twin injection units was a compounding extruder from Berstorff Maschinenbau GmbH of Hanover, Germany (Figure 11).

Gravimetrically metered resins and additives (PP and talc at the show) are plasticized and compounded under optimum conditions before being directly fed to the shooters. The melt is only heated once, so there is minimal stress. Lower cost neat resins can be bought in bulk and used as needed instead of more expensive pre-compounded pellets, and costly additives can be precisely metered in.

Another in-line-compounding example was shown by Oima. The Italian manufacturer showed a production model of its Greedy Mixer, designed to compound-in reinforcements and recycled materials at the injection machine and feed it to the plasticizing screw. The continuous mixing of the composition eliminates any structural or dimensional changes in the added fiber, thus avoiding dimensional shrink typical of compounded materials. Both preparation time and cost are reduced, Oima says, while the plasticizing is still done by the screw, as is the actual mixing. The Mixer is equipped with connections to the computer control to provide automatic regulation of the entire process.

Airgo, a new company based in Lüdenscheid, Germany, was a newcomer to the K fair, but it came with a different kind of horizontal molding machine that few will soon forget. It is an all-pneumatic press. Every moving part of the machine is driven pneumatically through proportional pressure control. Airgo's machines can deliver a clamp force of 770 kg at 7 bar or 1000 kg at 9 bar. Shot sizes range up to 20g via the machine's plunger injection unit driven by two air cylinders. It operates at a silent 60 dB. It is an attractive machine with a bright aluminum extrusion construction, including the platens, an open base around the clamp for three-way parts conveyance, and all-transparent PC guards. It can even be supplied with the company's own parts-removal robot . . . a pneumatic robot, of course.

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