First news from the big show.

This report went to press less than a week after the doors closed on the biggest plastics show of all time. We held open space for just a sampling of some of the newsiest highlights of K'92 in Dusseldorf, Germany. (Some additional tidbits are tucked into this issue's Newsfocus and New Products sections.) Watch for the story in full next month.

INJECTION MOLDING 

A number of new machine lines were introduced, particularly in the small-to-medium tonnage range. Other news in primary equipment included specialized machinery for molding recycled plastics. Some of the most interesting exhibits were the start of what could be a new wave of all-electric servo-driven machines from Battenfeld and Klockner; live demonstrations of metal-powder molding by Arburg and Nissei; a super-fast CD machine from Krauss-Maffei; and a recycling injection machine from the same supplier.

SMALL AND MIDSIZE PRESSES

Mannesmann Demag (U.S. office in Torrington, Conn.) introduced its Ergo-tech line of hydraulic and toggle machines from 27.5 to 275 U.S. tons. They include five fully hydraulic machines of 27.5, 38.5, 55, 88, and 110 U.S. tons. Each is available with either the compact or modularly expandable versions of Demag's new NC4 control. Five toggle machines of 110, 132, 165, 220, and 275 U.S. tons are also equipped with the modularly expandable NC4 control. In addition, each toggle machine is available in a special S version for fast-cycle molding.

Hydraulic models have two clamp cylinders and a volume multiplier built into the end plate. This reduces piping and sealing and provides a small machine footprint. The volume multiplier allows high speeds without additional quick-clamp cylinders. The clamp units on the toggle machine provide 10% spare locking force. Two new clamp cylinders extend inside the clamp unit, providing a space-saving design. All machines in the line have a quick-barrel-change system with central connectors for heater bands and thermocouples.

Battenfeld (West Warwick, R.I.) has broken into the low-cost mini-machine market with its new CD Plus series of injection machines. The new models of 27.5 and 38.5 tons have two rather than four tiebars and hydraulic clamping. Distance between tiebars is 10.6 in.sq. Mold height can be varied by a simple mechanical adjustment. A new injection unit provides injection pressures of 14,500 to 29,000 psi. The machine can be equipped to mold thermosets or elastomers. A new Unilog 1020 process-control system, based on hardware of the Unilog 2040 and Unilog 4000 systems, was developed especially for the series.

RECYCLING'S THE THING

In what was certainly the most "environmentally conscious" plastics show ever seen, systems incorporating recycled plastics were prime attractions. Two exhibits demonstrated a "sandwich" molding technique using dual injection units. A third unit combines compounding and injection molding of recycled material into one process.

Injection of a PP-foam recycled core layer between two skins of solid virgin PP was demonstrated by Nissei (Anaheim, Calif.) on an 80-ton injection molding machine with twin injection cylinders. Stork Plastics Machinery of Holland (represented by Genesis, Mississauga, Ont.) demonstrated that 40% recycle could be sandwiched between two skins of a bucket only 67 mils thick. This thin-wall feat was achieved on a 550-ton machine using sprueless molding and sequenced injection from the twin barrels through valve gates.

A highly unusual prototype system for recycling contaminated thermoplastics was demonstrated by Krauss-Maffei (Florence, Ky.). Reground PP/EPDM bumper material was molded into wheel-arch liners on a specially equipped 250-ton machine. The recycle was plasticated in one barrel and fed through a continuous, self-cleaning melt filter (from Berstorff), which removed paint chips and dirt. The filtered melt was then fed into the depressurized vent section of a second barrel, where it joined a stream of virgin melt plus additives, before being injected into the mold. This system eliminated separate compounding and pelletizing steps for the regrind material.

A CD RACEHORSE 

Krauss-Maffei scored another coup with its novel 44-ton CD machine that was claimed to be the fastest in the world. It molded a single disc in 4.47 sec at the show, though it normally does 4.2-4.4 sec in production, and can achieve 3.8 sec, according to a company spokesman. A big part of what makes it so fast is a so-called "ring cavity"--the center section of the mold between the stamper and opposite mold face--which slips sideways out of the mold area and is replaced by a second empty ring cavity. Thus, the mold-opening stroke is only 1.83 in.

The machine is very compact, thanks to a fully hydraulic clamping system that pulls on each tiebar, rather than pushing on a central cylinder. All cylinders are connected by fluid channels, so as to equalize clamping pressure. (Systems that clamp on all four tiebars are normally only seen on very large machines.) Another novelty is the incorporation of two small water-temperature controllers built into the machine base.

EXTRUSION

Although new equipment debuted for every type of extrusion, some of the biggest news came in process control. New automatic profile control systems for blown film were introduced while the latest high-tech "transputer" control system made its first appearance on a pipe and profile line. On the equipment side, new flat-die technology and an intriguing new application for pipe corrugation equipment turned up for the first time. Next month, read about the latest in extruders and downstream equipment as well as some new types of turnkey systems.

BLOWN FILM

Dominating the blown film news, the show saw an unprecedented proliferation of new and redesigned automatic profile control systems. For example, Windmoeller & Hoelscher (U.S. office in Lincoln, R.I.) rolled out a completely revamped Optifil P system. Like the first commercial models it introduced in 1986, the new Optifil P-2 still relies on die-level control. This new model, however, has given up air actuation in favor of a new cartridge heating system. Rather than blowing compressed air on the die wall to correct profile deviations, the new system heats the die's land area directly to thin out thick spots. Comparing the new Optifil to its predecessors, U.S. extrusion systems sales manager Andrew Wheeler says the new generation eliminates the cost of compressed air. It also reduces start-up and reaction times by almost half, thanks to the faster action of heating the die.

W&H also showed what may turn out to be a real step saver for blown film operators: a hand-held controller reminiscent of a home-television remote. An operator simply points this palm-sized unit at the main control console to adjust the full range of process points, even from the top of the tower.

Reifenhauser GmbH (Peabody, Mass.) had not one but two auto-profile control systems available for inspection. Its top-of-the-line flexible-lip die, the Reicoflex, was up and running at the company's Troisdorf lab. Working at the show was the new lower cost Reicoflow, which employs a segmented airring approach.

Alpine, Battenfeld Gloucester Engineering, and Kiefel also showcased their previously introduced auto-profile systems, all of which rely on air-ring control.

Another approach to auto-gauging also emerged at K'92. Octagon Process Technology of Wurzburg, Germany, employs an air ring to exert control on the bubble. Yet rather than a segmented vane arrangement, its air ring uses a flexible interior lip to control air flow. Stepper motors deform the lip to direct the air. Currently only a single-lip model is available, but Addex Inc. in Boston will soon offer a dual-lip version to the North American market.

In addition, Reifenhauser introduced its first dual-lip air ring. Called the Reiflow, it features separate valves for the upper and lower lips. U.S. product manager Hector Marchand says an operator can change the amount of air going to one level without affecting flow to the other, reducing the chance for bubble destabilization. For low-cost gauge control, an optional vernier handle allows the operator to manually tilt the top lip to focus more air on any thin spots. To make adjustments, an operator simply slides the vernier to any point around the circumference of the top lip. According to v.p. Matthew Bangert, this option alone can help cut gauge variation by as much as 20%.

CAST FILM AND SHEET

Extrusion Dies Inc., Chippewa Falls, Wis., unveiled a collection of brand new flat-die technologies, including an upgrade of its automatic gauge control system. The Autoflex 5 features improved thermal diebolts. According to field sales manager Harry Lippert, the new bolts let the system respond nearly twice as fast as the previous model and also double the range of adjustment available at a given temperature. The improvements come from a new, but unnamed, material for the bolts.

Another metallurgy change involves a new tool steel developed in conjunction with EDI's steel supplier. Lippert explains that the new steel needs no flame hardening and so eliminates the localized soft spots that used to plague a die's flexible "hinge" and land areas. The new steel comes alreay hardened to 44 RC while the older matreial arrived at 28-32 RC and had to be hardened to 48-52.

FOR PIPE AND PROFILES

Pipe corrugation equipment supplier Corma Inc. of Toronto, Ont., has set out to challenge the blow molding process. By arranging a sequence of different vacuum forming mold blocks on the corrugator's endless track, the machine can produce a chain of individual parts without uniform cross sections. These parts can then be cut apart after extrusion. Says v.p. Ken Bennett, the system allow continuous processing of items normally made by blow molding--an alternative with considerably longer cycle time. On hand at the booth were single parts with multiple diameters, oval cross sections, and even side ports. Bennett says an automotive customer already uses such a system.

Battenfeld (Gloucester, Mass.) has applied its new top-of-the-line Unilog TC40 "transputer" controller to its pipe and profile lines for the first time and will henceforth make it a standard feature. This new electronic architecture (PT, March '92, p.13) relies on the parallel-processing concept for expandable real-time control and SPC capabilities. The system can provide closed-loop control of not only temperature and gravimetric feeding, but also of downstream equipment. The swivel-mounted operator panel features an integrated keypad and flat color LCD screen.

BLOW MOLDING

Much of the blow molding news at K focused on new tool and platen layouts that dramatically simplify mold access and downstream parts handling, increase cavitation, and cut scrap. In extrusion blow molding of bottles, Krupp Kautex (U.S. offices in Edison, N.J.) unveiled a new modular "bobbing" head concept. Bobbing heads have been seen before, but not in recent decades from a major machine builder. Krupp showed two new models for the first time that feature rocking multi-extruder/head sections, driven by a single hydraulic cylinder on the principle of a balanced teeter-totter. (Gravimetric material feeding is done from a stationary platform above the moving extruders using flexible feed hoses.)

As the head rises, parisons drop into tools that close and shuttle straight sideways on rails to blow stations, rather than moving down and to the side on big hydraulic shuttle arms. The blow mandrel can roll sideways on bearings to open top access to tools. And takeoff and down-stream parts handling is all done on the same level. One of the new bobbing-head machines is a four-cavity, twin-sided KEB10D, making three-layer F-style gallon bottles with view stripes. This layout allows wider cavitation (Krupp is also building an eight-cavity single-head machine).

Another novel way to streamline shuttle movements is a patended system believed to be the first two-station machine with single-side takeoff. It also happens to be the first two-station shuttle in the Hesta line from R. Stahl Blowmolding of Germany (represented in the U.S. by FGH Systems Inc., Denville, N.J.). The new Hesta HKD501 moves the blow pins forward after bottles are blown to meet a robotic takeoff unit. The takeoff shuttles unobstructed back and forth, removing bottles from the two blow stations by turns and transferring them to the punch-out station for flash removal. Hesta also brought its first accumulator-head model to the show.

UNUSUAL SHAPES

Elsewhere in accumulator-head machines, low-flash 3-D blow molding of complex technical parts drew admiring crowds. Battenfeld Blow Molding of Germany (whose U.S. offices just moved to Boonton, N.J.) showed 3-D parison manipulation by means of integral robotic grippers that grab the parison at top and bottom. In producing a C-shaped PP automotive duct, the mold closed around the center vertical section, while slides remained open on top and bottom. The robotic grippers turned the parison sideways, laying into the horizontal top and bottom sections, before the slides closed. While this clever feat was performed on an existing BFB8-60 model, Battenfeld has designed a new dedicated "3-D" machine and will build the first one early next year.

In stretch-blow molding, two companies undertook what's said to be the first demonstrations of blowing narrow-necked OPP bottles, using both reheat-stretch-blow and injection-stretch-blow machines. Bekum made small OPP bottles on an RBU225 reheat-blow model with patented oven modifications. An air-cooled central wall between two rows of preform heaters removes convected heat from preforms, leaving only the more controllable heating by infrared absorption.

Reportedly even more difficult was injection-stretch blowing of a larger narrow-necked OPP bottle for sterile solutions by Nissei ASB Co. of Japan (U.S. office in Atlanta). These one-liter bottles, blown on an ASB-650NHII machine, weren't as clear as Bekum's and had whiter necks and bottoms, but also demonstrated greater hoop or sideways stretching of the preform than is usual for PP (4:1 hoop ratio vs 2.5:1 normally) accomplished by preblowing only in the hoop direction during conditioning.

Nissei also showed its first reheat-blow machine, the ASB-V12 with a single preform loader feeding up to six single-station wheels for conditioning and blowing.

An impressive demonstration of tool-change flexibility was put on by Aoki Technical Laboratory Inc. (represented here by Formex Inc., Dayton, Ohio), which lined up three nearly identical small injection-stretch-blow machines and interchanged blow and preform tools among them in under an hour.

THERMOFORMING

Thermoforming news at K focused on quick mold changes and improved repeatability. In thin-gauge forming, novel QMC technology from Sencorp Systems Inc., Hyannis, Mass., utilizes what may be the only "hose-less" water/air hook-up directly to holes in the tooling with O-rings. This trick, borrowed from injection molding, means the lines disconnect with a single lever as the tool is released.

Several unusual new thermoformers were talked about at K but showed only in pictures. Cannon Shelley of England (U.S. offices in Mars, Pa.) has built its first two high-speed rotary thermoformers and will bring one to the U.S. early next year. Cannon Shelley, which had specialized in single-station and shuttle machines, sees its new rotaries as the key to unlock the high-production U.S. market. The rotaries feature a "revolutionary new indexing system" using "a linear electronic device" that makes indexing "better controlled, more repeatable and virtually maintenance-free," Cannon says.

RECYCLING

With recycling the keynote of the show, an astonishing number of turnkey systems were featured, many of them gobbling plastic waste generated at other booths. Several firms also arranged side trips for demonstrations, such as to witness direct extrusion of unwashed film waste at Ereme GmbH (which just opened a U.S. branch in Topsfield, Mass.) and at Kuhne GmbH in St. Augustin, Germany.

Among builders of turnkey wetgrinding and washing systems, Refakt Anlagenbau GmbH, a joint venture of Herbold Granulators and B&B (represented by Herbold Granulators U.S.A. in Sutton, Mass.), discussed new developments in removing PVC contamination. Refakt has a new flat-bottomed hydrocyclone, said to separate 99% of PVC from PS (both heavier than water) rigid flake without adjusting the density of a water solution. Refakt is also developing a new PET extruder said to vaporize residual PVC and draw it off during extrusion, leaving less than 20 ppm of contamination.

RIM

The most unusual new RIM machine design was from Krauss-Maffei (U.S. office in Florence, Ky.). Intended for reinforced-RIM (RRIM) systems with fast-curing resin systems, the new system is designed along the lines of an injection molding machine. The two lance cylinders are mounted horizontally instead of vertically, and are hard-plumbed directly to the close-coupled mixhead. Cylinders and head are mounted on a moving sled that brings the head up to the vertical clamp for the shot and then retracts the head afterward.

The advantages of this design are said to be its speed and accuracy. The reciprocating sled is said to be faster than a robot mixhead manipulator. In addition, there is a very short path from the cylinders to the head and then to the mold. Because there are no material hoses than can shrink and swell with pressure fluctuations, ratio accuracy reportedly is improved. No hose pressure-drop compensation need be considered, either.