Injection Molding (K 2001 Preview)

All-electric machines will be one of the biggest themes in injection molding machinery at this year’s K show, where at least nine firms will bring out their first models. Show visitors will see the first all-electric machines for DVDs, among other applications.

Also on hand will be machinery systems that combine twin-screw compounding and molding. Other novelties will include coinjection of sandwich structures with a single barrel, degating parts inside the mold, water injection molding, and a new microcellular foam process.

Also expect to see larger PET preform machines and new machines for structural foam, liquid silicone rubber, and thermoset polyester molding.

 

Electrics & hybrids abound

The world’s first all-electric tiebarless machines will be shown by Engel of Austria (and Guelph, Ont.). A prototype was shown at K’98. Dubbed the “e-motion” series, the first 10 machines went to U.S. customers. The initial line-up of 60, 110, and 165 tons will all appear at K. The 110-tonner boasts a dry-cycle time of 1.6 sec. Engel plans to start building these machines in Canada next year.

These machines differ from Engel’s standard hydraulic tiebarless models in that they have a five-point toggle clamp and the patented Flexlink compensation linkage is mounted behind the stationary platen rather than the moving platen. Belt-driven ball screws drive all machine functions. Each model offers a choice of three injection units with screw diam. from 18 to 40 mm and two injection speeds—130 mm/sec standard and 260 mm/sec high-speed version. Injection units from hydraulic models can be used on e-motion machines. The same basic CC100 controller is used for hydraulic and electric machines. However, the electric models have additional standard control features, including the new “Mixing Degree Control,” which balances screw speed and backpressure to achieve a preset degree of melt mixing.

In addition, an e-motion machine at K will demonstrate a prototype of Engel’s new CC200 control, which will be launched commercially around the middle of next year. It has a graphical display in place of text and touchscreen instead of keyboard data entry. Internet interface is standard, which facilitates remote troubleshooting or automatic e-mail messages to service departments in case of malfunctions. Also new is an “Electronic Assistant” that will advise the operator on optimizing set-ups. The CC200 also permits full user programming of mold-movement sequences and integrates robot controls into the machine console. The control will also be shown on Engel’s new Victory hydraulic tiebarless models.

Battenfeld Injection Molding Technology (U.S. office in West Warwick, R.I.) will introduce its EM line of fully electric machines, starting with a 176-ton model. These are based on Battenfeld’s all-electric CDK-SE series but will offer a wider size range and more injection and clamping options. The series has two servo motors and a belt-driven planetary-roller screw for the injection unit. Unilog B4 controls receive position information through new non-contact sensors that are said to reduce the scanning time by a factor of 10 to 0.1 millisec. This allows for greater precision than on the CDK-SE series. Larger and smaller models will be introduced next year.

The new 88-ton Allrounder 420 A 800-350 model from Arburg (Newington, Conn.) is its first step into all-electric technology. It has a five-point toggle, and all the main axes of motion are driven directly with servomotors. However, auxiliary axes such as ejector, core pull, and shutoff nozzle can be driven hydraulically or electromechanically.

Netstal (Devens, Mass.) will show its first fully electric injection machine—a prototype 132-tonner with a toggle clamp. The firm expects to roll out a commercial line of all-electric machines from 40 to about 175 tons in 2003. These will not just be “me-too” machines, promises president and CEO Dieter Klug, and more than one type will be offered.

The K show will host the debut of a line of fully electric machines from Taiwan-based Victor Taichung (sold here by Fortune International, Somerset, N.J.). The Va-Series uses four Japanese servomotors combined with a ball screw and timing belt to operate injection, plastication, ejection, and clamping. Dual ball screws govern mold movements. The machine reportedly offers faster cycles than conventional hydraulics.

MIR Presse of Italy (MIR USA is in Leominster, Mass.) will unveil the first model in its “e-power” all-electric series. A 200-ton model, designed for high-tech and value-added applications, will later be supplemented by models from 140 to 400 tons with injection capacities from 10.4 to 59.3 oz. They are said to feature 30% higher injection speeds than standard. For example, the 200-tonner injects at 130 mm/sec. Four AC motors are used, two for the injection unit, one for toggle clamping, and another for ejection. A three-phase electric motor drives screw plastication.

Negri Bossi, which earlier this year re-established a presence in North America with a new office in Concord, Ont., will roll out two new presses in its brand-new VE line of all-electric machines. Geared for high performance applications, they share the toggle-clamp design and fieldbus communication architecture of Negri Bossi’s hydraulic units. The firm will bring 176-ton and 231-ton models to the show.

Negri Bossi will also introduce the hybrid V 700, a new 770-tonner with a variable-frequency electric screw drive to reduce energy consumption. Also, the machine’s low axis improves access to the molding area.

Krauss-Maffei (Florence, Ky.) will roll out the Eltec line of hybrid electric machines based on its two-platen C series. Four sizes will be available: 55, 88, 121, and 165 tons. The beltless system uses a dedicated AC servomotor for each of six axes of motion. Plastication and injection movements come from “direct-drive” servomotors whose spindles are integral ball screws. A self-contained hydraulic system, itself driven by a servo motor, provides clamp force. Standard Eltec units generate injection speeds from 100 to 300 mm/sec.

Demag Ergotech (Strongsville, Ohio) will introduce new sizes of its El-Exis hybrids. The E Series of standard machines, first introduced in a 165-ton size, will gain new models of 66, 110, and 137.5 tons. A 220-tonner will arrive next year. The high-speed, accumulator-assisted El-Exis S line has been expanded to eight models with a new 385-ton unit. Other models range from 66 to 330 tons.

JSW (Elk Grove Village, Ill., and Anaheim, Calif.) will show an unusual hybrid machine for MuCell microcellular molding. It has electric clamping and hydraulic injection. (JSW will have an all-electric MuCell machine at Plastics USA in Chicago next month.)

Other machines at the show will include all-electric models from Nissei (Anaheim, Calif.) and the hybrid Hylectric line from Husky Injection Molding Systems Ltd., Bolton, Ont.

 

DVD machines go electric

Netstal, which claims to be the world’s largest seller of machines for optical disk production, is introducing two new electric machines for CDs and DVDs, including the world’s first fully electric model. Single- or twin-cavity production of all current (and future) disk formats can be run on the new 55-ton “E-jet” unit. Its 2.5-sec cycle time is similar to Netstal’s hydraulic DiscJet machines. Injection pressure and speed are the same as on the hydraulic unit. The new model features five AC servomotors. Netstal’s DSP control is integrated with new control hardware and a 15-in. color screen. Up to four temperature controllers are built into the machine for convenient operation and maintenance. E-jet will be commercially available after the K show.

Netstal will also roll out a hybrid hydraulic/electric model in the fall, which will eventually replace the DiscJet series. This unit will have variable-speed electric screw drive and hydraulically driven injection and clamping.

Krauss-Maffei will showcase its new Triathlon series DVD 5 unit, which has an electric direct-drive system capable of injection-compression molding. Based on its new Eltec hybrid line, the machine reportedly can hold 10-20 micron tolerances on CDs or DVDs due to the ability of the all-electric drive to maintain consistent shot weight and clamp movement.

 

Compounding & molding

Krauss-Maffei will demonstrate twin-screw compounding joined in-line with an injection molding unit. Such a system allows for use of long-glass reinforcements and facilitates custom formulating by the molder. K-M, which showed a prototype in-line system at K’98, will introduce its first commercial machine, model KM 1000-6100 IMC. It will produce a car tailgate at the show, using a back-compression process whereby a multi-layer film is inserted in the mold, and glass-reinforced ABS is injected behind it. A special injection unit yoked with a corotating twin-screw extruder replaces the conventional plasticating unit. An accumulator unit joins the extruder’s continuous operation and the molding machine’s discontinuous operation.

During the show, Husky will offer tours to its Luxembourg large-machine facility, where it will be running a 330-ton injection press with a Coperion Werner & Pfleiderer 40-mm twin-screw compounder mounted over the plunger injection unit. Continuous glass rovings fed into the compounder end up as long-glass fibers in PP parts.

Engel will highlight its Fibermelt process of long-fiber molding by letting down a 75% glass concentrate. Good results have been obtained with Engel’s new “fiber-friendly” screw and new fiber-friendly hot-runner system from Mold-Masters Ltd., Georgetown, Ont.

 

Multi-component molding

Two-material sandwich structures can be produced with a single conventional barrel by means of the new Twinshot process developed by Twinshot Technologies in Rifton, N.Y. The new technology, to be introduced at the K show, employs a screw-within-a-screw design that handles two independent melt streams. The two are combined at the screw tip, which has an internal shutoff valve (see diagram). This simple design is said to lower the cost of coinjection, which typically requires specialized machines, and thereby make it available to more molders. The process can produce hard/soft combinations or encapsulate off-spec, regrind, or recycled material in the core of the structure—all in a single cycle.

Netstal’s SynErgy 2C line of machines for two-component applications will be extended with a new 660-ton model. The line previously ranged from 60 to 420 tons. Netstal will demonstrate co-molding of PBT and thermoset liquid silicone rubber (LSR).

Battenfeld will also demonstrate molding of thermoplastic and LSR in one step to produce a shower-head insert.

Special tooling that allows production of a three-component medical part will be demonstrated by Demag Ergotech using technology from Gram Technology ApS of Birkerod, Denmark. Shown for the time, the system rotates the center plate of the machine in increments of 90°, permitting three injection stations. Previous dual-injection versions rotated the plate 180°.

Sandretto Industrie SpA, (offices in Freedom, Pa.) will show a 550-ton model in its Series Nine that will be outfitted with a second injection unit from Windsor, a new member of the Cannon Group along with Sandretto. This modular, retrofittable PlugExpress injection unit will be equipped with the Logigas gas-assist system.

 

Two platens proliferate

MIR has extended its HMPC Compact line of hydromechanical two-platen presses from 950 tons all the way up to 10,560 tons. This unit was constructed by pairing a couple of two-platen machines, both featuring two moving and two fixed platens and weighing 60 tons each. The system has two 240-mm-diam., 24:1 screw injection units that can each inject up to 96.3 oz/sec. The machine was sold to make 220-lb industrial containers; it can fill the mold in 18.2 sec.

Demag Ergotech is moving up the size range with its Ergotech maXX line of two-platen machines. The first was a 2200-tonner, several of which have been built in the past year. The first 2750-ton model will be built in the second half of this year, and a 3300-ton design is now available.

Ferromatik Milacron (Batavia, Ohio) is showing the smaller two-platen Maxima models that have come out over the past year. The line, which previously extended from 725 to 6600 tons, now includes models of 170, 225, 310, 450, and 550 tons.

Engel has extended the size range of its Duo two-platen line, which now spans 770 to 6050 tons. The newest addition is an 880-tonner. All models have a new simplified hydromechanical tiebar-locking system, in which the two split nuts are driven by one hydraulic cylinder instead of four. This simplification adds reliability and also cuts cycle time by about 15%.

Battenfeld is introducing a new compact, two-platen version of its HM hydromechanical series. This 1430-tonner also has telescoping tiebars, which provide open access to the mold and ejector mechanism.

Meanwhile, Battenfeld has introduced a number of improvements to the standard HM line. They now boast larger clamping cylinders, faster clamp movements, and increased mold height and opening stroke.

 

New toggles to ogle

Parallel movement of the mold and ejector can cut cycle times by 5-8% on the new Extra line of machines from Demag Ergotech. These simplified units have a short list of options and a reduced overall price. Aimed at the European market, nine models from 27.5 to 220 tons have hydraulic clamps on units up to 100 tons and toggles for larger sizes. Fewer options on the injection unit and screw help keep prices 10% below conventional machines of similar size, such as Demag Ergotech’s Viva line.

Demag has also upgraded its Viva line with the option for parallel functions, and one model at the show will demonstrate the new parts-handling equipment (PHE) system that is integrated in the guarding of the molding machine. Developed by Neureder AG of Oberding-Schwaig, Germany, the system allows threaded parts to be unscrewed while the mold is opening. At the end of the opening stroke, the ejector transfers parts to a robot.

Battenfeld will introduce a new high-speed toggle machine for packaging applications. The TMS line is based on the TM series. It will be offered in sizes of 143, 176, 231, and 297 tons. Features include a 22:1 L/D mixing screw and control of each motion axis by servovalves located close to the cylinder being controlled.

Netstal is filling out its SynErgy line of toggle presses with a new 550-ton model.

Victor Taichung will also release its new Vr-CE series of five-point toggle machines from 50 to 550 tons. They have new controls and a “semi-closed-loop” hydraulic system for injection.

 

Hydraulic presses advance

Arburg will unveil its largest machine to date—a 352-tonner dubbed the Allrounder 720 S. It has 720 x 720 mm platens and can mold parts weighing up to 44 oz. It will be shown with an electric screw drive.

Battenfeld has redesigned the smaller end of its HM series so that machines up to 176 tons now have direct hydraulic clamping with two clamp cylinders, while models of 231 tons and up retain the two-step hydromechanical design.

Sandretto has a new range of small machines called the Idea line. A 77-tonner will be shown.

Engel will show off its new Victory series of hydraulic tiebarless machines. Their uniform platform accepts different combinations of standard technology modules to optimize price/performance and cut delivery times. Of three standard variations, “Tech” is the basic machine for normal jobs. It carries a richer package of standard features than before. “Speed” is the fast-cycling variant, which has an electric screw drive to permit overlapping screw and clamp movements. “Power” is the version for engineering parts; it permits parallel movements of clamp and ejectors or cores. The Victory line now spans 82.5 to 165 tons. The full line is planned to range from 22 to 660 tons.

 

PET preform machines

A 144-cavity preform system joins Netstal’s PET-Line series for 32 to 96 cavities. Using three-stage cooling, it will mold half-liter carbonated soft-drink preforms weighing 20.8 g on 11-sec cycles (50,000 units/hr). The injection and clamping unit is the same size as on the 96-cavity unit. The new machine will be available next year.

Chen Hsong Machinery Co. Ltd. of Hong Kong (new offices in Keswick, Ont.), will show its first Chen-PET preform machine, able to generate 7000 preforms/hr. The turnkey system includes a press, 32-cavity hot-runner mold, robot, and conveyor all operating under a single master control.

Krauss-Maffei will show off improvements to its Petline preform system that reportedly cut energy use by 12% and cycle time by 10%.

 

Other novelties

Battenfeld will introduce an in-mold degating mechanism that eliminates post-mold trimming. It was developed in cooperation with Werkzeugbau Summerer Technik und Vertriebs of Rimsting, Germany.

At least two exhibitors will demonstrate water injection. Engel will show its Watermelt process, and Battenfeld will make a two-color part hollowed out by its Aquamould technique.

Trexel Inc.’s MuCell process is no longer the only microcellular foam technique on the market. Demag Ergotech is introducing its own Ergocell process, which uses CO2 injection to achieve up to 50% weight reduction. Unlike MuCell, the process uses a conventional 20:1 L/D screw.

Wilmington Machinery Inc., Wilmington, N.C., will bring out a special 375-ton machine for wood-filled compounds. The two-stage unit has produced PP with up to 30% wood fiber.

 

New for thermosets

Krauss-Maffei is one of the few machine exhibitors to put any emphasis on thermoset molding. Its Siloset two-component LSR unit has a new check valve that improves by a factor of 10 the shot-weight control of even low-viscosity materials.

K-M also has a more durable check valve for its polyester BMC machines. A new 715-tonner will also be introduced. The company now offers thermoset machines for larger parts with shot weights up to 19.8 lb.

 

Structural-foam news

Structural foam won’t receive much emphasis at K 2001, except from Wilmington Machinery. Wilmington will present a number of new developments:

• More modular manifolds tailored to the mold, permitting faster set-up.
• Individually controllable nozzles that permit a wide range of filling sequences.
• Higher injection pressures and more generous flow passages that allow use of higher-viscosity materials (fractional-melt grades).
• Direct CO2 injection into the barrel for lower densities and finer cell structure.
• A new hybrid electric machine that reduces energy consumption and increases performance.