Injection molding.

Reporting on the triennial plastics fair in Dusseldorf, Germany, with its 2227 exhibitors from 40 countries, covering 33 football fields worth of booth space, requires some attempt to be selective. We concentrate in this issue on new developments in primary machinery that are likely to interest North American processors. To get it all in, we won't repeat all of what was previously covered in our "first highlights" sampling last month (p. 15) and in our two show previews (Sept. '92, p. 51 and Oct. '92, p. 35). Some show news in materials and additives appears elsewhere in this issue; some appeared last month and in the September preview, and more will appear in subsequent issues. Next month, we'll conclude the machinery report with new developments in RIM and urethane equipment.

K'92 was overflowing with news for injection molders. One area of particular activity was small machines, which saw introduction of new models, as well as attention to special molding applications, such as multicomponent molding and metal or ceramic powder injection. Gas-assisted injection also starred at many machine suppliers' booths, where both thermoplastic and thermoset applications were demonstrated. Other notable highlights were high-speed presses for CDs and packaging, and energy-efficient all-electric machines.

LOTS OF SMALL MACHINES

Several new models of small machines have been added by Arburg. The All-rounder M series has been expanded to include a machine with 14.5-in.-square mold area and clamp forces of up to 110 U.S. tons. Two new machine models, 270 V and 370 V, round out the V series at 33 U.S. tons. Both are outfitted with the new Sealogica control system. There has also been an increase in the dimensions of the C series. The new 470 C machine has a mold area of 18.5 in. square and a 143-ton clamp.

A new rotary-table, vertical-clamp insert molder from Arburg is based on the Allrounder M design. The injection unit is mounted vertically on the moveable platen, or can be mounted horizontally at the parting line. The Allrounder Rotary Table is available with clamps from 44 to 143 tons.

One area of growing importance for Arburg may be metal- or ceramic-powder injection molding. All Allrounder machines reportedly can process these highly filled materials, using either central or horizontal-displacement injection (the "Vario Principle"), producing shot sizes up to 22 cu in. Arburg says it can provide expertise in raw-materials preparation, molding, and debinding and sintering of the parts.

Several improvements to the Boy 50 (50-ton) machine were on hand. Tiebar clearance has been increased from 12 to 13.2 in., and the clamp safety guard has been enlarged to increase the available space around the mold. The injection unit has been redesigned, replacing two horizontally opposed hydraulic pistons with a rotary piston system that has already been proven on the Boy 80. It's said to reduce the mass that moves during the injection process. Injection forces are not transmitted to the screw drive bearing, and injection profile control is said to be significantly improved.

The Boy 50 also includes an improved variable-displacement pump with electrohydraulic volume and pressure regulation. In the new version, no differential pressure is required to adjust the pump, thus reportedly enhancing pump efficiency. Pressure is monitored by a sensor in the pressure system, and throughput is measured by a position sensor on the pump piston.

In other improvements, the Boy 80 (80-ton) models have increased tiebar distance from 14 in. to 16 in. Also, the Mipronic Plus controller includes a new interface for a product weigh scale with tolerance monitoring, which can be integrated with a separate device for rejecting off-spec parts.

Battenfeld expects a good reception in the U.S. for its two new low-cost "mini" machines the CD Plus 250 and 350 (27.5 and 38.5 tons, respectively). These modular, hydraulic-clamp machines have only two tiebars, so they aren't intended for high-precision molding. But they're said to have generous specs for machines this size: tiebar spacing of 10.5 in. square, max. daylight of 17.6 in., clamp stroke of 7.8 in., shot sizes of 0.8-2.3 oz (PS), plasticating rates of 0.2-0.5 oz/sec, injection rates of 35-97 oz/sec, and injection pressures of 14,500-42,800 psi. Dry-cycle rates are said to be 1.33 sec. The machines are fully enclosed and incorporate special seals that suit them to clean-room operations. They come with a new Unilog 1020 microprocessor control, said to be similar in many hardware and software features to the Unilog 2040.

A new line of small general-purpose injection machines is planned by Sandretto for introduction during the second half of this year. The small machine line is being developed by a separate group drawn from both Sandretto and its Metalmeccanica subsidiary.

MORE ELECTRICS

As previously reported (Sept. '92, p. 51; Dec. '92, p. 15), Battenfeld and Klockner Ferromatik Desma introduced the first European all-electric servo-driven injection machines. Spokesmen for both firms said they expect to see many more all-electric machines at the next "K" show and that these machines will carve out a substantial niche in the market, based on energy efficiency, precision, cleanliness, and quietness.

Battenfeld's new 55-ton CDK-SE all-electric machine with five servo-controlled axes was a prototype--they won't go on sale until midyear. The machine has a spindle drive and thus eliminates the use of toothed belt systems, which reportedly can emit rubber particles into the air. Also suiting the machine to clean-room uses, its "maintenance-free" clamp unit requires no oil lubrication. Battenfeld uses liquid cooling on the motors, eliminating the need for cooling fans. Although the price has not yet been set, a goal is that it should cost no more than 25% than a comparable hydraulic machine, according to Battenfeld of America marketing manager Rudi Loehl.

Klockner (represented by KFD Sales & Service) offers a new Elektra series of all-electrics in 66, 110, and 193 tons. Like the Battenfeld machine, these do not use belt drives, which is said to be more suitable for cleanroom environments.

A new version of the Cincinnati Milacron/Fanuc all-electric machine is called the ACT-III series. The controller now features a 32-bit RISC processor, and includes a new standard-feature color flat-screen display and user-friendly screens. Dry-cycle time is up to 50% shorter than before. The ACT-III 35 (38.5 U.S. tons) improved its clamping speed by 52%, its ejector speed by 67%, and injection speed by 60%. Tiebar spacing, clamp stroke, and ejector stroke have all been increased over those of the ACT-D series. Other improvements to the ACT-III include 360|degrees~ barrel shield, improved visibility of the injection unit and tool, and improved clamp design with greater bearing area in the toggle linkage. The ACT-III is available in clamping forces of 38.5, 66, and 198 tons.

ON THE FAST TRACK

Last month (p. 17), we reported on an unusual 44-ton machine from Krauss-Maffei, specially designed for CD molding, which reportedly molds a single disk in as little as 3.8 sec (4.47 sec at the show), said to be the fastest in the world. The company guarantees 4.9 sec. Other interesting aspects of the system that were not reported last month include the use of two venting gates instead of the usual one, uniform temperature on each mold face (normally different), and special CD molding software including a stamper-change sequence. Two aspects of mold design are also significant. First, the sprue has undercuts so that it can be pulled away from the disk; then a central piston within the ejector pushes the sprue out of the undercuts, and it is blown out of a channel in the back of the mold by an air jet. Unlike the usual system that punches the sprue out of the disk, no dust is said to result, avoiding potential contamination. A second mold-design feature is the specially contoured edge of the disk that eliminates the possibility of projecting flash from the spin-coated lacquer. That flash can easily be broken off, potentially damaging the disk's data surface.

Other high-speed molding demonstrations included a CD "monoline" system from Nissei, incorporating an injection-compression press with automatic stamper changing device, and operating at a more normal 5.5-sec cycle.

Netstal showed publicly for the first time a two-cavity CD production line with a Netstal Disc 60 press, mold from GPT Axxicon of Holland, and production cycle time of 6.5 sec, or 1100 CDs/hr.

Netstal also showed off a high-speed line for molding 3.5-in. floppy-disk shells on an HP 1750-870 machine with a 4+4-cavity stack mold, and molding on a 4-sec cycle. Parts-conveying and stacking equipment was supplied by Hekuma of Germany.

And that wasn't all from Netstal. It also showed high-speed integrated Pack Line production system for thin-walled dairy-tub containers with downstream stacking and boxing. The tubs, of BASF Novolene PP with an MFI of 45, were formed in a two-cavity mold with a cycle time of 3.1 sec. An MP 580/150 machine combined with a super-fast robot said to be 10-20% faster than free-fall ejection to provide a cycle time of 2.8 sec.

In addition, Netstal demonstrated in-mold labeling of 1-liter PP food containers (two cavities) on an HP 2400-870 with around 4.5-sec cycle.

Nuova Plastic Metal (NPM) of Italy (represented by R+R Plastic Services, Inc.) demonstrated 3.3-3.5 sec production of four PP flower pots (3 sec is said to be usual in actual production) on a 220-ton press. Extremely rapid parts removal was accomplished by two suction heads on either side of the mold, which swung into position via a rack-and-pinion mechanism mechanically linked to clamp motion.

A similar cam-operated vacuum take-off system was shown molding four PP yogurt cups in around 2.7-sec cycles. The machine was a 154-ton model of Fahr Bucher's high-speed SGA-S series, which are being introduced in North America by Bucher Inc. (see Industry Newsfocus).

Engel demonstrated its new fast-cycling ES 1300/200 SL machine for medical parts. The SL series comes with accumulator, reinforced frame, and extended platen support. The hydraulic system allows up to three simultaneous movements. Opening, closing, and ejector movements are closed-loop controlled by a proportional valve. Hydraulic hoses and the accumulator are covered by panels. A "Power Control" program reportedly provides efficient power consumption by the screw drive when plastics with very different plasticating properties are molded on one machine. The ES 1300/200 SL machine ran a 160-cavity hot-runner mold for syringe needle caps on a 5-sec cycle.

MIR's RMP 200/V Futura II machine with special high-speed modifications has an electric screw drive, special high-throughput plasticating unit, accumulator, and Moog servovalve. The water manifold includes 12 lines in and 12 lines out for faster cooling.

Toshiba reportedly plans to introduce a line of high-speed hydraulic-clamp machines from 390 to 610 tons to North America later this year. The machines are said to cycle 20-30% faster than standard hydraulic machines.

A new SX range of toggle presses was introduced by Stork Plastics Machinery (represented by Genesis Plastics Machinery). The SX line ranges from 110 to 880 tons in three versions: SX-N for general-purpose molding; SX-T for high-precision molding; and SX-P for thin-walled products. The line includes a newly designed five-point toggle clamp with large opening stroke.

GAS-ASSISTED INJECTION

Gas injection seemed to be on display everywhere at K'92. Battenfeld won the prize for quantity: seven machines demonstrated its Airmould gas-injection technology, all fed by a central nitrogen pressure-generation unit with nitrogen recycling, though each press had its own gas control unit (mobile or stationary). The Battenfeld exhibit also provided space for two computer stations where two mold-analysis software vendors, AC Technology and Plastics & Computer Inc., demonstrated their new gas-injection simulation software.

A number of first-time public gas-injection demonstrations at the show included Arburg's gas technology, Battenfeld's thermoset gas-assisted injection (of pelletized polyester molding compound), and Hettinga Technologies' HELGA (Hettinga Liquid Gas Assist) system. The HELGA method, was first announced at NPE '91 and has been commercially available for about six months (PT, Aug. '91, p. 36). The process involves a one-time licensing fee and no on-going royalty payments.

A new compact gas-injection nozzle has been developed by Cinpres Ltd. The new nozzle has a poppet design that is completely sealed at injection, and does not require a heating coil.

A new 55-ton tiebarless injection machine for two-color molding was on hand from Engel Machinery. The ES 200H/80V has a supplementary vertical injection unit. The tiebarless design is said to offer more accessibility for applications requiring bulky molds or supplementary devices.

Thermoplastic/thermoset molding of a polycarbonate telephone component with a liquid silicone rubber seal in the same mold and machine was demonstrated by MIR on a model HSLR 135/C Futura.

An even more unusual application of three-component molding in a single mold was demonstrated by Klockner. Air vents for a Volkswagen car interior consisted of a housing with five mobile louver blades and a rod connecting the five blades, which emerged from the mold as a completely finished product. The process used two incompatible materials (PBT for the blades and PP for the rod and housing), so that different materials, when solidified, wouldn't stick to each other and prevent free movement of the component parts. The system employed one vertical and two parallel horizontal injection units, one injection unit for each movement of the mold. The injection units injected simultaneously into three stations of a rotating mold, producing components of three parts at a time. In the first station, PBT louver blades were molded; then the motion rod of PP was injection molded onto the blades; finally, the housing of PP completed the part. Total cycle was about 30 sec. The process was demonstrated on an FX 100-3F molding machine with a clamp force of 110 tons.

CLAMPING & QMC DEVELOPMENTS

A prototype of a "self-clamping mold," that eliminates the conventional clamping system on injection molding machines, was demonstrated by Hettinga Equipment. It's designed for low-pressure molding of very large parts, and reportedly can complete with other large-part processes, such as SMC, RIM, vacuum forming, or FRP hand lay-up. The prototype mold was installed on one of three stations on a Hettinga injection machine, which molded a 4.41-lb, one-piece chair body with 140 tons of pressure. The system is said to be capable of producing parts weighing up to 221 lb. Reported benefits of the self-clamping system are easier mold changing and greater access to the mold, as well as savings in floorspace, energy consumption, and tooling costs.

A space-saving hydromechanical clamp design that comes from the former East Germany was demonstrated by Hemscheidt GmbH. The clamping unit, available on machines from 550 to 3300 tons, has four short tiebars, which retract during each cycle. The end of each tiebar is specially configured to engage a locking mechanism on the fixed platen. Four individual clamp cylinders on the fixed platen then pull on the tiebars to generate clamp force. This type of design, used on many larger Japanese and Italian machines, appeared for the first time at this show on smaller models from Klockner and Fahr Bucher, as well as Hemscheidt. Hemscheidt claims benefits of up to 40% less floor space than conventional clamping machines (a sign proclaimed "the smallest 500-ton |metric~ machine"), and easier access for mold changes and robotic parts removal. Although Hemscheidt does not yet market actively in the U.S., the company is considering establishing a presence here, according to a company spokesperson.

A manual bayonet system for quick clamping of injection molds was introduced by Staubli (Duncan, S.C.). The system consists of two bayonet locking plates and a removable lever, and centering rings for each mold. After quickly positioning a mold between the machine's tiebars, the platens are closed and the locator and centering ring reportedly guarantee precise positioning. Molds are secured with simple manual locking of the centering ring.

A new quick mold-clamping system was introduced by Stork Plastics Machinery. The simple and integrated system consists of cams and clamping cylinders that require little space. A simple small-diameter hole is all that is required for mounting it on the platens.

ENERGY SAVINGS & OTHER MACHINE DEVELOPMENTS

Energy savings was the dominant theme from MIR, with the introduction of its Ecologica machine. It's said to use 50% less energy and up to 80% less water than standard hydraulic injection machines. Energy-saving features include an a-c inverter screw motor and a-c inverter on the hydraulic motor, which generates only the amount of flow needed for each cycle. Both features result on a lower volume of hydraulic oil, as well as less water needed for cooling.

Engel showed a new long-stroke machine for molding deep-draw parts, such as furniture and refuse bins. The ES 7000/500LH has a toggle clamp with extra-long opening stroke, double-flighted screw for good homogenization at high plastication rates, both fixed- and variable-volume pumps, and an energy-saving program that can switch off pump motors completely during long cooling times.

Engel also extended its tiebarless concept into mid-size machines with the ES 330/100 HL, a 110-tonner. The absence of tiebars allows the entire 29. x 27.5 in. platen area to be covered by the mold. The latest unit includes a new power-control package, which adjusts flow at a constant system pressure.

A new Mega series of injection molding machines with clamping forces from about 600 to 5500 U.S. tons were introduced by Sandretto. The so-called Mega T series, covering machines up to about 1100 tons, have toggle clamps. The Mega H series, from above approximately 1400 tons, has hydromechanical clamping through four jaws that lock the tiebars mechanically and four large-diameter hydraulic on the end of the tiebars.

Several improvements to the Series Eight A.T. line of toggle machines (66-485 tons) were also displayed by Sandretto. Among these was the adoption of injection units permitting modular machine configurations. Each injection unit is capable of accepting a range of general-purpose and specialized screws. And the hydraulic system now includes fast-response proportional valves for higher accuracy. The A.T. series is equipped with the new high-end SEF 100 controller.

NEWS IN CONTROLS & CIM 

Engel gave a first glimpse of its new CC 100 controller, which is based on a 32-bit RISC processor, providing improved reaction times for fast operation. It will become available around mid-year.

A new Sealogica controller from Arburg includes graphics and symbols capabilities, thereby enhancing its suitability to handle complex production processes. The heart of the control is the Selog process management, in which the machine cycle is entered as a flow chart using graphical symbols. This "guided programming" is said to simplify set-up; upon selection of a process symbol, all corresponding parameters are called up automatically.

An IBM-compatible AT/386-based MC3 controller was exhibited by Fahr Bucher. The MC3 is being made available for the first time in the U.S., and its use has been extended beyond the company's SGA-series injection machine to its TS series for thermosets.

A new SEF 100 controller, designed with so-called "open architecture," to facilitate communication with other intelligent devices, was introduced by Sandretto.

Husky demonstrated the full integration of its latest generation of machine controllers with CIM software from Syscon-PlantStar (see PT, Apr. '92, p. 13). As an option available for $10,000-20,000, the PlantStar process and production monitoring screens are embedded within the Husky controls. The user can toggle back and forth effortlessly between Husky's machine operating screens and the PlantStar monitoring screens. The system eliminates the "black box" interface and automatically uploads processing information from the molding machine to the PlantStar host computer.

A "black box" interface for the PPC 2000 and CPC 2000 process control systems was exhibited by Moog Inc. It's said to eliminate wiring between the controller and injection molding machine. Moog-Buhl reportedly also is developing a fully closed-loop control system for release in the near future.

HOT RUNNERS

A line of machine nozzles was introduced by Mold-Masters Ltd., Georgetown, Ont., each internally heated with a 200-240-v element metallurgically fused to the nozzle for maximum heater life.

A new SM 20 hot-runner control system from Mold-Masters offers an expanded operator interface, RS-232 communication, low- and high-voltage output, and 15 amps per zone--all in a compact package. An optional Communication Terminal Package offers a graphical user interface, remote and local setup, and menu-driven simplicity. It's also available in a touchscreen version for fast setups on the press.

A new series 9000 line of hot-runner temperature controllers from Husky feature a digital display with diagnostic features and ability to communicate with other equipment. Built for Husky by Gammaflux of Sterling, Va., they're based on proportional voltage power output and PID2 control, ensuring constant power supply to the heater independent of line voltage, and limiting the amount of overshoot. Two models are available: 9152 (two-zone, 15-amp), and 9034 (four-zone, 3-amp). An optional minipanel allows a global trim of all zones with a single command, programmable startup conditions for a timed cycle before switching to running conditions, and ability to store a setup program to automatically set up all controllers for a mold.

The Sealed Edge Gate hot-runner nozzle was also new from Husky. It allows edge gating single or multiple parts with engineering resins by eliminating the insulator bubble found in most edge-gate systems, which can be a source of resin degradation. To eliminate any dead spots between the nozzle and cavity wall, a seal is created as the heated inner material of the nozzle expands and forces the seal ring against the gate wall. A small gap is left between the seal ring and the gate-well wall to provide thermal insulation. The seal-ring design also distributes the sealing load around the entire gate well, overcoming "gate punch-out." The sealed edge gate is also said to facilitate color changes, because the open-flow design flushes out the melt path quickly. The nozzle is available in sizes of 0.71 in. and 1.26 in.

Husky's new Ultra hot-runner system has beefier replaceable nozzle tips for greater heat transfer to the gate area, and also addresses the possibility of mechanical damage from thermal expansion in cases of overheating or from cold starts. A patented disk-spring assembly provides a preload that ensures that sealing occurs between the nozzle housing and the manifold, even before any heat is added. As the system comes up to operating temperature and the manifold expands, the springs take up the expansion and ensure a complete seal.

Another key feature of the Ultra nozzles is their "clampless," slip-on heater bands. These eliminate the bulky clamp and grip the heater as a result of thermal expansion. Instead of the usual two bands, which can create two hot spots, a single slip-on band covers the nozzle length, with profiled internal heater windings to provide temperature uniformity.

Several improvements to hot-runner systems were on hand at Enrietti S.p.A. (represented by Alba Enterprises). Manifolds are now available with optional Calrod heaters rather than cartridges, which reportedly can help to concentrate the heat where it is most needed. The flow paths in manifolds are now more rounded, to minimize degradation of materials such as PVC and aid quick color changes. In addition, a new valve-gate system permits fine adjustments to the length of the pin, made through the valve assembly.

Heitec GmbH (represented by JPI Technologies) displayed its new valve-gate nozzle, in which the valve stem is guided inside the nozzle. Benefits are said to be low stack height and no wear on the bushing and the gate. The company claims that this valve gate exhibits no wear problems at the stem, even when running 30% glass-filled nylon 66.

ROBOTS AND AUXILIARIES

A new three-axis servo-driven robot series, designated TCS (traverse) and TCS-E (longitudinal), intended for high-speed molding at cycle times under 6 sec, were introduced by Battenfeld. A specially designed drive unit for the main discharge axis mounts the servo motor in a stationary position at the end of the axis. This is said to reduce the weight of the carriage and optimize stability.

Also introduced by Battenfeld are new Uniswift sprue pickers for machines above 55 tons.

A new parts-handling and palletizing system was introduced by Arburg as the latest version of its automated factory concept. The robotic handling system is electric servo-driven, and both the handling and palletizing system are controlled by the new Sealogica control system.

An interesting demonstration of high-speed camera-based mold inspection was performed at the Mannesmann Demag booth by CSD International. One of the new Demag Ergotech models (Dec. '92, p. 15) was running a 16-cavity mold on a 3.7-sec cycle. Using two compact video cameras and fiber-optic lighting, CSDI's computer system was able to inspect all 16 cavities for hung-up parts within 0.125 sec--and that included 0.07 sec waiting for the parts to fall out of the way!