WEB EXCLUSIVE:K 2001 preview: Machinery

Not surprisingly, all-electric and electric/hydraulic hybrid molding machines will be obvious attractions in many stands at K this year. But look a little closer and you'll find another fascinating array of specialized machines for everything from PET preforms and inmold decorating to microcellular and multimaterial molding systems. Following is a peek at some of the machines that will be in Düsseldorf. Be sure to check these pages in next month's issue for more previews. 

Visitors to Arburg's stand will see new machines from the Allrounder line, as well as demonstrations of the MuCell process, micro injection molding, durometer processing, and liquid silicone molding. The largest machine Arburg has manufactured to date, the Allrounder 720S, will make its debut. With a platen that measures 720 by 720 mm, a clamping force of 350 tons, and a new injection unit, the press allows production with maximum part weights of 1240g. The injection flow on the system can be increased with the use of a hydraulic accumulator, and a reduction in cycle time can be achieved by tool- or part-dependent mold height adjustment. 

The Allrounder 420A will also make its debut and represents the company's first step towards modular technology. The unit features a five-point toggle clamp and combines hydraulic and electromechanical drive concepts. In the basic version all main axes are directly driven servoelectrically. The auxiliary axes, ejector, core pulls, and nozzle can be moved individually, hydraulically, or electromechanically. The machine can be expanded to accommodate additional modules and a fully electric version is possible. 

Also look for the two-component Allrounder 630S, with an electric rotary platen and three stations. The machine will manufacture a mobile phone case that is removed at the third mold station by a robotic system with the mold closed. 

Arburg will also showcase a vertical production cell based on the Allrounder 420C. The production unit comprises the machine, robotic system, part cooling system, a central material feed and drying system, a suction conveyor, and a dyeing system. 

SMS Plastics Technology attempted to sell its Battenfeld injection molding machinery business toward the end of 1999. However, the deal fell through. The company now says its development strategy includes injection technology. Probably the best proof of that is the variety of new machines and technologies that SMS/Battenfeld is introducing at K, including a new series of electric molding systems. 

The EM Series that Battenfeld will launch is a second-generation all-electric. Though it uses design features of the previous CDK-SE Series, the EM is positioned quite differently, focusing on precision, speed, and efficiency. At the show, a 160-ton EM 1600/350 B4 will mold a medical product. Battenfeld will offer clamp forces from 50 to 200-tons in the near term, and in the future they may get still larger. 

The EM's design uses six servomotors with two drive units mounted parallel to the injection unit for injection and holding pressure. The company says this basic design is similar to its previous electric machines because it makes the injection unit compact, which keeps the footprint smaller. A servomotor drives the injection unit through a planetary roller screw and a toothed belt. A two-stage transmission achieves high nozzle contact force and fast travel speed. The ejector is driven by a toothed-belt drive and a ballscrew drive. Special sensory technology protects the mold. Battenfeld's top-of-the line Unilog B4 control system is standard on the EM Series. Noncontact sensors monitor every stroke. A very fast control scan time offers good precision of all movements. Battenfeld expects pending patent applications to be resolved by K so it can release more technical details. 

Battenfeld has added a number of new models to its TM Series toggle clamp machines since they first appeared three years ago at K 1998. At K 2001 it will introduce the TMS (130-, 160- and 210-ton models) for high-speed thin-wall applications like caps, food tubs and cups, electronics housings, connectors, and plugs. 

Features include short dry cycle times, fast injection speeds at high pressure, and a 22D screw offering high plasticating capacity. The toggle clamp geometry is optimized for speed and to destress the tiebars. Extensive FEM analysis was used to design platens that avoid deformation during rapid open/close sequences. Each axis is controlled by an adjoining servovalve. The servovalve for the clamp is near the clamping cylinder, and the valve for the injection unit is just above the injection cylinders. 

Apart from metering, which uses a separate pump, each movement is driven from an accumulator system. Each lubrication point has its own monitored metering system, and there is no oil at the clamping unit. At the show a 160-ton TMS with a Waldorf Technik double inmold labeling system will make up to 1400 decorated margarine tubs (.45-mm wall) per hour in a two-cavity mold from Hofstetter of Switzerland. 

Visitors to K will see new smaller machines and a two-platen option in Battenfeld's HM Series. The smaller machines include a range from 50 to 450 tons. Up to 160 tons clamp force comes from direct hydraulics. From 210 tons upward, closing force is hydromechanical. Overall, the HM Series now offers more mold height, longer opening stroke, higher precision, shorter length, and a larger array of options. 

One of those options is the new two-platen clamp design, which also features telescoping tiebars. Battenfeld says it acquired the basic technology from Hemscheidt and modified it. The aim is to give molders a choice, which is why two-platen is an option. Battenfeld says that since it previously redesigned the injection unit to make the overall machine shorter, using the two-platen clamp produces an extremely small footprint. In addition, the telescoping tiebars support lateral mold changing and oversized molds. A 160-ton two-component HM machine at K will produce a shower head that combines thermoplastic and liquid silicone. A 190-ton HM machine, also two-component, will demonstrate a new IMD technology that allows the cutting of decorated parts inside the mold to eliminate downstream processing. The inmold cutting technology was developed with Summerer Technik of Germany. The demonstration product is a textile-decorated, installation-ready automotive B-column with molded-on sealing lip. 

Battenfeld's Aquamold system will be at K. Using water instead of gas reportedly reduces cycle times by 50 to 70 percent as water inside the molded part provides cooling from within while the mold cools it from the outside. Battenfeld's technology will be at the IKV (Institute for Plastics Processing of Aachen, Germany) booth. The IKV performed several years of core development work that is being used by most of the companies commercializing the water-assist process. In the IKV stand a 210-ton Battenfeld TM machine will use the Aquamold system to help produce a two-component racket for a beach ball game. 

Battenfeld's small Plus machines (25 and 35 tons, horizontal and vertical) have received a facelift with a newly added Unilog B2 control. At K, a 35-ton Plus will make a tub from Prosine, a new protein-based material with excellent elasticity modulus that is also waterproof and dimensionally stable, besides being biodegradable. 

On exhibit at BM Biraghi's booth will be five Sintesi injection molding machines. Each machine is equipped with the new fiber-optics-based Elios 3200 control system. The Sintesi 200 machine is designed for use in medical applications as the system contains features that prevent contamination of the molded part. For the K show, a cylinder for a 5-ml syringe will be molded. 

From the Twin Line of molding machines will be the Sintesi 175. It will manufacture a two-component part molded in different colors. All two-color and two-component Twin Line machines come from a standard machine design that uses a second injection unit (always standard). This unit can be excluded for monocomponent molding. The sequence involves the rotation of an index table from the inside of the mold and the injection of the two materials takes place simultaneously. A Sytrama robot will extract molded parts and place them on a conveyor belt. In addition, the Sintesi 175 Twin will be fitted with a small vertical injection unit; the materials used will be thermoplastic rubber and PP. Cycle time is approximately 30 seconds. 

At the show, the Sintesi 330 will produce a transparent lamp cover for a polycarbonate street lamp. The machine has an electric drive that is controlled by an inverter on the dosing phase. For those interested in PET, the Sintesi 100 PET will mold four-cavity preforms for 5-liter bottles. Visitors to BM Biraghi's booth will also find a 25-liter flower vase being molded on the Sintesi 580. The mold is supplied by the Swiss company Otto Hofstetter and a Sytrama robot will be used for extraction and placement. 

Chen Hsong Machinery will display its 32-cavity Chen-PET system, which debuted in 1998 as a 12-cavity system. The system allows major components such as hot runner molds, molding machines, robots, and conveyors to operate under one master control. The market success of the system—it has been sold into Eastern Europe, Southeast Asia, and South America—is one reason for CHM's decision to participate in Düsseldorf. In addition, research done by CHM says that the annual global consumption of PET is approximately 6.1 million tons and will double by 2003. 

Engel's new water-assist molding technology is out of the prototype phase. At K its Watermelt system will mold a curved automotive coolant pipe of DuPont's Zytel nylon 6/6, 35 percent glass filled, in a 150-ton tiebarless machine from the new Victory Series. Following the show, the system goes into production making a similar but still confidential application. 

The Watermelt system includes nonchemical infrared water conditioning technology to keep the water clear of bacteria. A servomotor in the press-side unit, says Engel's Process Engineering Manager Georg Steinbichler, adds to making it as precise as the rest of the system. Watermelt can pump up to 30 liters/min of temperature-adjusted water, synchronized with the mold cycle. 

Water, says Steinbichler, gives a big advantage in cycle time compared to gas. Deciding which to use is dictated by the part design. One guideline says gas is better for eliminating sink marks in large, relatively flat parts like TV cabinets, while water is better for sizable hollow sections. Parts-per-hour yield can generally be doubled compared to gas. Steinbichler says payback on Engel's Watermelt system is about six to seven months. 

Perhaps the most frequently asked question concerns residual water in the part. A high-temperature material like the PA used in the auto coolant pipe turns the water to steam, which is easy to remove. With lower-temperature materials like PP and PE, water can be blown out using pressurized air. Part design permitting, a second water pin lets water flow in and out in a closed circuit. A spillover cavity for the excess resin pushed out by the water should be considered in the design stage. 

Noting the patent difficulties that existed with gas assist, Engel is saying there is no problem with water, and cites a patent that predates and overcomes the "gas" patents even though they use the word "fluid" in describing the process. Engel doubts current moldfilling simulation software can predict water's effects, and therefore the machinery maker is collaborating with material suppliers such as DuPont to ensure material resistance. 

At the demo, after the melt is injected, water at 150 bar will be injected via a second nozzle to press the melt against the cavity wall. The mold has a spillover cavity for melt forced out of the mold. The vibration-absorbing coolant pipe (25-mm OD, 3- to 4-mm wall thickness) is 50 percent lighter than a steel pipe and can be made in a 35-second cycle. The unspecified cost benefit is described as significant. Engel feels many current gas applications can convert profitability, and it is now developing a number of water-assist applications with various molders. 

Intended for small, thin-wall (up to 50g), and microprecision parts, the new X-Melt process Engel will show at K uses high melt pressure to accomplish fast injection without separate hydraulic accumulators. The key is a patented needle shutoff nozzle. Closed, it allows melt pressure to build to 2500 bar following metering. Opening the valve allows the pressure to "expand" the melt into the mold. 

At its Austrian development lab Engel recently showed a mobile telephone battery box made of an ABS/PC blend, with a 3.2g shot weight and .4- to .5-mm walls. By building melt pressure to 2400 bar, injection takes 60 ms. Compare that with 80 ms using a hydraulic accumulator at an injection speed of 1000 mm/sec. In addition, part weight variations were reduced from ±.07 percent to ±.03 percent. 

The energy needed to fill the cavities is about a third the usual requirement since there is no need to accelerate, advance, and decelerate the screw. Screw advance is required to compress the melt, but it is not time-critical. Engel is developing a system with Mold-Masters to make this work with hot runners. 

Engel says its new Victory Series machines follow the auto industry's strategy of using standard technology platforms with modules that can meet the needs of most any market. Shown for the first time at K, the Victory Series offers clamping forces of 75 to 100 metric tons. There are three standard variants: Tech, Power, and Speed. Tech is the basic standard machine for normal injection molding jobs. Power and Speed are equipment modules that build on the Tech. 

Power, which is meant for molding engineering parts, permits the parallel movement of the mold and ejectors or cores. The Speed variant is a fast-cycling machine for applications such as packaging. The screw is driven by an electric motor and other machine functions are hydraulically driven from a central accumulator to permit parallel movements. The three standard variants can be further adapted to individual requirements with optional modules. Engel says the Victory machines also provide a considerably improved price-performance ratio. 

It comes as no surprise that Engel's new e-motion all-electric machines, which will be shown for the first time at K, are tiebarless. A 55- and 150-ton model will be available at show time; the range will eventually reach 200 tons. Three injection units with screws of 18 to 40 mm are available for each machine size. There is a choice of two injection speeds: standard is 130 mm/sec, while the "fast" version is 260 mm/sec. 

The design is based on the time-tested C-frame of Engel's hydraulic tiebarless machines; however, the e-motion's toggle clamp called for a few modifications. What Engel calls its "power frame" was given an inner guide for the moving platen and toggle clamp. Linking the stationary and moving platens, says Engel, creates a balance of forces for mold protection and support. Engel's Flexlink, which ensures parallelism of the stationary and moving platens, is not mounted on the moving platen as in the hydraulic machines. It is between the stationary platen and the outer frame. 

The five-point toggle clamp features a central, single-stroke lever for opening and closing the mold and applying clamp force. Driven by a servomotor with crankshaft, the five-point toggle permits fast movements to keep unproductive phases to a minimum. Dry cycle time is about 1.6 seconds. 

Separate three-phase synchronous motors drive all axial movements, including forward and reverse movement of the injection cylinder, ejector strokes, and opening and closing the clamp. Mold height adjustment is electromechanical via threaded spindles driven by three-phase asynchronous geared motors. 

The rotary motion of the electric motors is converted to linear motion by ballscrew drives and toothed belts transmit the high rotational speeds of the motors to the spindles. The motors are equipped with the angular displacement transducers normally used on machine tools for accurate stroke measurement. By providing absolute values for position and stroke, they eliminate calibration. 

All pressure measurements are made by external pressure sensors. The settings for the electric motors are managed through the control system and transmitted via high-speed interfaces to the motor controls. A new Mixing Degree Control monitors the interaction of screw speed, screw retraction, and the resultant backpressure during the metering operation. The injection unit swing outs for easy cylinder changing, and the plasticating units are interchangeable with Engel's hydraulic machines. The e-motion is now built in Austria; building at Engel's facility in Guelph, ON begins in 2002. 

Engel's new Control 2000 technology, the next generation of the current CC 100 controls, will be in operation at the show on a Victory 1050/150 Power machine and one of the new e-motion all-electric systems. When it enters the market in mid-2002 as the CC 200, it will offer simple interlinking of control systems and easy visualization of all control data. The text-oriented display of current controllers will be replaced by a graphic interface that includes command input via touch-screen technology. Artificial intelligence will support the operator to correct or change control sequences. An Electronic Assistant will guide the operator through a mold and production optimizing process. 

Husky will feature multiple systems molding parts, along with displays highlighting hot runner components and complete hot halves, stack molds, PET preform molds, robots, and Quadloc large-tonnage machines. Among the machines highlighted at the stand will be a 100-ton Hylectric with a 24-cavity, hot runner closure mold; a multimaterial 180-ton Hylectric with a two-cavity housewares mold and a Husky TE3 top-entry robot; and an 880-ton Hylectric running a two-cavity pail mold. For those interested in inline compounding of long-fiber-filled parts, visit the Werner & Pfleiderer exhibit to see a 330-ton Husky machine at work. 

As Krauss-Maffei brings its Eltec all-electric machines into the open for the first time, it is not overlooking the basics. The company says it is using its proven two-platen technology from its C Series; other features include a compact form factor, large mold dimensions, space for peripherals, and easy access for mold changing and parts removal. The Eltec machines, available in clamp forces of 50, 80, 110, and 150 tons, offer a choice of five injection units and four screw diameters. 

The Eltec delivers injection pressure of 1500 to 3000 bar at injection speeds from 100 to 300 mm/sec. A direct-drive, high-torque synchronous motor is used for plasticating and injection performance. Krauss-Maffei is stressing that the machines are designed for high precision, speed, and cleanroom capability. For example, linear guides ensure parallelism to hold tight tolerances. Clamp force buildup is fast thanks to a hybrid system that uses the electric motors to "almost" close the mold. A hydraulic system then does the final close and hold using only 2 liters of oil in a no-maintenance closed circuit. 

All elements of the clamp unit drive system are encapsulated and the motors are water-cooled for cleanroom adaptability. Krauss-Maffei patented the way it uses two servomotors inline on the back end of the screw. The front motor handles injection and the back motor is active for plasticating, driving through the front motor. The speed differential of the two motors turning in the same direction creates holding pressure. The motors are modular and capacity can be increased by lengthening them without changing the diameter. Motor braking force is captured in a circuit to reduce overall power requirements. 

At K 1998, Krauss-Maffei showed a prototype of a system where inline compounding takes place just before injection. The IMC System, already a commercial product, will make the tailgate of a car at K 2001. Using a back compression process, glass-fiber-reinforced ABS is injected behind a multilayer film already in the mold to create a finished part. The IMC technology ties a corotating twin-screw extruder to a special injection unit and uses gravimetrics to feed polymer and additives, like long-fiber glass, to the extruder. Krauss-Maffei will ultimately offer IMC Systems on 800- to 5400-metric-ton machines with injection units that can handle up to 40 kg (88 lb) of material. 

In response to the exceptionally stringent tolerances on DVD disks, Krauss-Maffei is introducing an electric, high-precision version of the Triathlon Series optical disk production subsystems. The new system uses precise linear guides for platen movement to ensure mold parallelism. It also uses a hybrid clamping system designed for fast force buildup. The drive system for the clamp is completely enclosed so the system can meet the most rigorous cleanroom specifications. 

Tolerances for CD production are generally between 10 and 20 µm. Tough enough, but for the .6-mm substrate of a DVD overall tolerances are less than 10 µm. That puts significant demands on the accuracy of the shot weight, as well as the precision of the clamp movement to perform the coining process exactly. That is for today's DVD standard. DVD 18, already in use by audio/video professionals on a limited basis, takes the data capacity from 4.8 GB to 18 GB. That kind of data-packing density can only mean a further tightening of disk tolerances. Krauss-Maffei says the precision of electric machines is necessary to meet the challenge. 

In addition to new machines, Krauss-Maffei will show process technology improvements for clear coating parts in the mold, making larger thermoset parts, and precisely controlling LSR shot size. 

Putting a high-quality and clear PU coating is done by designing a mold that will maintain a continuous gap between an inserted item and the cavity surface. Two-component PUR is sent into the gap using a special Krauss-Maffei mixing head; the coating is done in one cycle with no postmold treatment required. One of the first applications applies a clear coating to burl walnut auto dashboards. It replaces a multilayer lacquering process that involves repeated coating and sanding over several days. The process is more environmentally friendly compared with the lacquering. Furniture and medical devices are other target markets. 

In line with a market trend, Krauss-Maffei is bringing out a 650-ton machine for BMC molding, and is modifying the design of its other machines to take taller, larger molds. This allows shot weights up to 9 kg (20 lb). Parts of that size have been traditionally made by press-molding. The injection-compression process allows for automation, optimized formulations, and shorter cycles. A critical factor is a newly developed and very durable check valve. The company has a number of other process technologies to support this program. 

In the liquid silicone arena, the Silcoset KM 65 on display features a new check valve design, which ensures precisely repeatable shot volumes despite the low viscosity of LSR. A needle valve seals off material flow at the cavity for leak-free shot control. Krauss-Maffei Silcoset machines, available in clamp forces to 200 tons, are part of its C Series. 

Ferromatik Milacron will present six injection molding machines at K, with clamping forces ranging from 55 to 550 tons. The company is convinced that all-electric machines will eventually dominate the industry, and thus three all-electric machines from the Elektra line will be demonstrated with clamp forces of 55, 110, and 220 tons. 

One machine on exhibit with an innovative twist is from the Die K-Tec Series. It is fitted with a mold equipped with a horizontal stack-turn system. Patented and constructed by Foboha (Haslach, Germany), the system allows twice as many cavities to be incorporated in the mold without increasing the size of the machine. In addition, using the "dice technique" the machine cycle is shortened considerably. The dice technique uses a mechanism that turns the center plate of the stack mold 90° or 180° between shots. The clamping unit allows the maximum platen distance to be quickly and easily modified by altering the pressure bolt length. Clamping forces on this line range from 45 to 500 tons; the machine at the show will be a 500-tonner. (For more on this mold system, see "Rotating Center Plate in Mold Turns Some Heads," November 2000 IMM, pp. 70-72.) 

The Maxima 275 and 500 will also be on display. Compact construction and rapid travel are features of this two-platen series. The Maxima 275 will mold an automotive dashboard from ABS for a Mercedes-Benz. 

Mir will demonstrate a 200-ton model of its new all-electric e-power Series injection molding machines. The toggle-clamp machines are available from 140 to 400 tons with injection unit capacities of 294 to 1680g. The toggle-clamp unit is entirely oil-free. Use of special antifriction materials eliminates lubricants on the clamp end of the machine. 

Mir says each model in the e-power Series equals the speeds and loads on its hydraulic and hybrid machines of the same tonnage—except for a 30 percent increase in injection speed. Injection speed of the 200-ton machine at the show is 130 mm/sec, a speed that requires accumulator pumps on many other machines. 

Inverters and encoders are active in all machine functions and the control system is fully digital. Eliminating analog signaling, says Mir, permits high-speed data transmission, drastically reduces the amount of internal cabling, and provides a base for the fiber-optic control network the company intends to use in the future. 

Most electric machines currently on the market use five or six motors. Mir's e-power design has only four: one for clamping, one for extraction, and two for the injection unit. These last two are coupled and mounted inline on the back end of the injection barrel. They can rotate clockwise or counterclockwise for plasticating, injection, and withdrawal, and they can go in opposite directions for counter pressure. 

Motor movement is applied to the plasticating screw through a ballscrew integral to the motors. Mir says that permits a reduction of the installed power compared with most electric machines of equal tonnage. A device integral to the extraction motor enables straight linear movement without belts or gears. Given the high cost of servomotors, Mir says having only four makes the e-power machines very market-competitive. 

Also at Mir will be an LSR version of its relatively new MPL Series tiebarless machines. Available from 50 to 400 tons, the MPL machines use a hydromechanical clamp that applies force with four high-pressure, short-str