MUNICH, GERMANY (Aug. 27, 11 a.m. EDT) — Krauss-Maffei Kunststofftechnik GmbH will debut an “electric” injection molding machine at K 2001, but it is not an all-electric press, the company said.
Despite the name, the Eltec is really a hybrid press that uses just 2 liters of oil to move the clamp into final position and build up the clamping force. Every other function is run by electric power, delivered by six motors over six axes.
“It's what we call almost an all-electric machine,” said Josef MÃ¤rtl, Krauss Maffei's managing director in charge of technical matters.
Eltec machines will come in four clamping-force sizes: 55, 88, 121 and 165 tons.
The injection unit boasts a direct-drive, high-torque, synchronous electric motor, which Krauss-Maffei developed with Siemens AG.
“We have a direct drive where the screw is actually used as an axle of the motor,” MÃ¤rtl said.
Instead of using a belt, KM engineers adopted a direct-drive system using a ball-screw mechanism.
The hydraulic components are fully self-contained, so the machines can be used in clean room operations, according to Krauss-Maffei. The company also is using the hybrid electric/hydraulic design on its new triathlon series of presses for making digital versatile discs.
Krauss-Maffei, which makes injection presses, extruders and polyurethane processing machinery in Munich, announced its K show offerings at a news conference in June.
Wilhelm SchrÃ¶der, chairman of Krauss-Maffei's managing board, said the Eltec was well-received in trials with U.S. customers.
Despite a strong start in the first few months of 2001, SchrÃ¶der also said he expects KM's sales to decline by 3 percent this year, to 491 million euros ($440 million). But he pointed out that 2000 was an exceptionally strong year for sales in Germany and other European Union countries.
Looking at individual markets, SchrÃ¶der said the automotive industry is predicting a slight weakening. The importance of the United States as a driver of growth and innovation is waning, as European carmakers take on that role. The optical disc and communications markets also should shrink slightly. Other market segments including packaging, appliances and medical will continue to invest in new production equipment, he said.
“While the slowdown in the U.S. market will have an increasingly negative impact on our sales, it will be counteracted to some extent by cautious growth in demand within the EU,” SchrÃ¶der said.
KM built 1,847 injection presses in 2000, up from 1,505 the year before. The company cited a trend toward small-tonnage machines as the reason for the jump.
Krauss-Maffei leaders focused on new technology during the news conference. Also new at K: production models of its injection press with a piggybacked compounding extruder, dubbed the IMC, for injection molding compounding machines. The company first showed a prototype IMC at the K '98 show.
Krauss-Maffei has sold five IMC machines since then, including three to an unidentified French processor, SchrÃ¶der said.
KM developed the IMC with extruder specialist Berstorff GmbH, a sister company under the ownership of Mannesmann Plastics Machinery AG. SchrÃ¶der said KM is looking for more cross-machine cooperation if it can benefit customers.
“To combine these two technologies is much easier for KM than for any other company in the world, because we have injection molding and extrusion capabilities together in one house,” he said.
As another example of two MPM units working together, Krauss-Maffei engineers are working on a machine that does in-line coating of polyurethane over extruded parts, according to SchrÃ¶der.
At K 2001, KM will run an IMC press molding a car tailgate. The part will be produced in a back-compression process where a multilayer film is inserted into the mold, then ABS compounded with glass-fiber reinforcements is injected behind it to produce the part.
Blending the technologies of injection, with its start and stop, and the continuous process of extrusion required KM to develop a special design. An accumulator shot pot, positioned between the two units, fills up during the injection and holding-pressure phases. The melt is piston-fed from the shot pot to the plunger injection unit on a first-in, first-out method.
Turning to pipe and sheet extrusion, Krauss-Maffei will showcase a new generation of counter-rotating twin-screw machines with two venting zones, compared with one zone on traditional machines. In this double-venting setup, the dry blend is fed to the processing unit, where it is compressed and preheated as usual. When it reaches the first venting zone, the material is compressed but is powdery, as air is allowed to escape. Another compression phase follows before the second vent, this one with a va-cuum to remove the rest of the air and volatile gases.
Removing air from the resin early in the process offers much better heat transfer, giving a 17 percent increase in output, according to Krauss-Maffei. The machine, with a length-to-diameter ratio of 36-to-1, can process 2,200 pounds an hour.
KM also continues to expand in direct extrusion, where material gets compounded, then goes directly into an extruder to make profiles, sheet and pipe in a single machine. The new KMG series will be displayed at K 2001.
Graziano Parisi, managing director who handles extrusion, said KM wants to increase its position in polyethylene water pipe. The company has developed a special screw and a pipe head with spiral distribution, for that market, he said.
Parisi is hoping the global construction market turns around. With the exception of China, construction is weak worldwide.
“North America used to be our ideal target market, but in 2000 the market sort of crashed. We are waiting for the market to recover,” he said.
Krauss-Maffei is taking advantage of the Chinese market by opening a sales and service office in Shanghai in June.
In polyurethane machines, Krauss-Maffei has introduced what it calls the first PU machine to make shoe soles using high pressure. Previous machines have used low-pressure technology, to ensure the soles are totally free of bubbles.
KM partnered with KlÃ¶ckner Desma Schumaschinen AG. The companies paired a new four-component mixing head with KM's new RIM-Star 8/8 mixing and metering machine. At K, a machine will mold shoe soles in three different colors, changing color on a shot-to-shot basis.
The company also will roll out a new version of its RIM-Star ECO II mixing and metering machine. The C version has a closed-loop controller with frequency converters to regulate throughput.
In reinforced reaction injection molding, KM announced that German automotive supplier Dynamit Nobel AG bought the first of its new type of RRIM machine, to mold car door sills. The system for making thin-walled parts uses a KM Comet piston metering reaction machine with an injection molding-type clamp, on a big two-platen machine. Parts are removed by robot, automatically trimmed and moved via conveyor to the assembly line. A second robot cleans the mold and sprays a mold-release agent.