Injection Molding: Faster, Smarter, More Efficient Machines Tackle Sustainable
pdt12ong21 > 12-21-2021, 03:07 AM
A profusion of new and upgraded injection machinery at K highlighted twin themes of Circular Economy and Smart Manufacturing. While presses keep getting faster, they also grow ever more energy efficient in kWh/lb of plastic processed. The vast majority of injection machines at the show were all-electric, hybrid, and/or servohydraulic. This year’s exhibits featured machines equipped to process large amounts of post-consumer recycle (PCR) or biobased materials.
Reducing waste and downtime also contributes to more efficient and therefore more sustainable manufacturing. In that vein, K 2019 saw a continued push toward greater self-regulation in processing, greater connectivity between machines, and improved communication between humans and machines as milestones along the road to Smart Factories and Industry 4.0.
The following report presents news not covered in our September show preview and elsewhere for a more complete picture of injection molding news at the show. See also Keeping Up and Starting Up sections of this issue for additional K-related news. A report on robots will come next month.
Going for the ‘Green’
Our September show preview highlighted several exhibits of machines from Arburg, Engel, KraussMaffei and Wilmington Machinery tailored to handle large amounts of regrind or PCR, in some cases through foaming and/or sandwich molding.
Other examples at the show included Boy Machines processing wood-plastic compound (Fibrolon from FKuR) on a Boy 125 E. Husky highlighted the ability of its newest HyPET HPP5e system to mold PET bottle preforms from 100% PCR with no sacrifice of cycle time or product quality (e.g., color). What’s more, the Husky machine can take molten PET reclaim directly via melt pipe from Erema, NGR, or other recycling systems, thereby eliminating pelletizing, crystallizing and drying steps and saving large amounts of energy. Husky says customers prefer this approach to feeding reground flake. This “RMTP” capability is expected to be commercial mid-to-late this year.Machine capabilities to process large amounts of recycle or bioplastics supported the “green” theme of K 2019.
Chen Hsong demonstrated three-layer sandwich molding with recycle in the core. It utilized a second injection unit and an adapter plate to divide the two streams. And Milacron showcased its M-Powered integration of iMFLUX low-pressure molding technology, which is said to adjust automatically for large variations in melt viscosity, a potential risk in processing PCR. Milacron’s multi-nozzle low-pressure injection molding machine (LPIM) technology for structural-foam and structural-web molding is already to handle up to 100% regrind, and testing is underway with iMFLUX on LPIM machines.
Another “green” thrust in molding exhibits involved processing of biobased materials. One impressive demonstration in this vein was Nissei’s production of champagne flutes from PLA bioresin. Nissei says PLA has poor flow characteristics, but was able to mold this deep-draw drinkware with what it claims is the thinnest wall ever molded in PLA—as thin as 0.65 mm over a flow length of 125 mm. To accomplish this, Nissei came up with a new way to inject supercritical CO2 into the melt to improve the fluidity of the material. Remarkably, the glassware is crystal clear, owing to the use of only 0.5% CO2 and the microscopic size of the gas bubbles.
The glasses were molded in two parts, a base and cup in a cell utilizing two presses with Cartesian robots that deliver parts to an assembly station with a Kawasaki DuAro two-armed collaborative SCARA robot. The machine were Nissei’s brand-new, all-electric NEX 280V-71E (details below). One press molded the 185 g cups in eight cavities in 37 sec, and the other molded 108 g bases (o.74 mm thick) in four cavities in 72 sec. (Nissei will be speaking about this application in the Green Molding session at the Molding 2020 Conference, March 17-19 in Lombard, Ill.)
A new option on J-ADS all-electric auxiliary machinery from JSW is said to be advantageous for molding thick-wall parts from PLA and other resins. The optional JS servo drive is said to enable extended hold times together with fast injection and high responsiveness.
Another unusual demonstration at K was the debut of a machine and material for molding a new kind of eco-friendly products. Zeroplast is a patented material from a Polish company of the same name (zeroplast.com) that is composed entirely of mineral and nonfood plant-derived waxes, fibers and fillers (including rice hulls and calcium carbonate). This “plastic-free” material is compostable and biodegradable in natural environments. It is also recyclable without any loss of properties, the company says. The material is said to be heat stable to greater than 200 C (392 F) in processing and to 70-75 C (158-167 F).
Zeroplast worked with Wittmann Battenfeld on an exclusive basis to develop a bowing molding machine process for this material. The result is a specially modified, all-electric EcoPower 240 press (240 metric tons) with a special injection unit, heating system, and processing software. According to Wittmann sources, this system was adapted to the Zeroplast material’s sharp transition from solid to liquid and the resulting narrow process window.
At the show, Wittmann molded a thick-walled cosmetic jar and cap with the heavy feel of glass, molded in two colors in 4 + 4 cavities, with a paper in-mold label (uncoated for biodegradability) and automatic assembly of jar and lid in a screwing station outside the press. (Wittmann Battenfeld will present this innovation in the Green Molding session at the Molding 2020 Conference.)
Developments in LSR
Apart from news reported in our September K preview, Fanuc of Japan (represented here by Milacron) has developed new standard software for LSR processing on Roboshot all-electric machines of 50 to 100 tons, as well as its own screw and barrel design for this process.
Sumitomo (SHI) Demag also introduced a turnkey LSR package for its IntElect series with a special screw, nonreturn valve, vacuum system and other LSR-specific options. For the pumping/metering system, the company has partnered with Nexus Elastomer Systems of Austria.
Elmet has shrunk its TOP 5000 P pumping system with 15% smaller footprint and 10% reduced height. Also, Elmet is developing an alternative to this pneumatically driven piston-pump system: the TOP 5000 E with servoelectric screw pump. Elmet says servo drive is more expensive and will offer the same precision as the existing version, but it is being offered to meet competition from other vendors.
Meanwhile, Elmet introduced a web-enabled Premium Connectivity Package with email functionality and remote support for the whole TOP 5000 series. All TOP 5000 dosing systems already have a VNC and OPC-UA interface for data exchange with the molding machine. The new remote-access interface allows users to change settings and monitor system status via the new Elmet Connect online portal and an app, without requiring access to the customer’s own IT network.
Incidentally, Elmet noted that the emergence of LSR 3D printing has opened up a new market. A single TOP 5000 system could feed 10 to 20 3D printers.
Zeiger Industries has enhanced its LSR conversion kits with new quick-disconnect water-cooling jackets for the barrel to facilitate maintenance. These also come in a toolless version. Also new is a connection to allow easier uncoupling of the pump assembly from the barrel. This version eliminates threads, reducing the risk of damage to the barrel in case of LSR leakage into the coupling, which can lock the threads.
More New Machines & Upgrades
Arburg introduced its first machine that can be configured with an app. The Allrounder 270 S compact (hydraulic, 35 m.t.), as the name suggests, has a space-saving design with reduced width and the control cabinet integrated into the machine base. It can be configured and ordered online with an app on Arburg’s customer portal in a few simple steps. The customer benefits from faster delivery and prices about 25% lower than standard hydraulic machines, Arburg says.
Arburg also initiated the spread of features launched with the new hybrid Allrounder “H” series at K 2016 to other Allrounder lines. At this show, the all-electric 570 A (200 m.t.) and 630 A (250 m.t.) appeared for the first time with the new “H” series clamp design, exterior styling, and Gestica controller with gesture-based commands.
Another introduction from Arburg was the vertical, hydraulic Allrounder 1600 T (200 m.t.) with a larger (1600-mm) servo-electric rotary table for automated overmolding of metal inserts, such as pipe fittings mold.
Boy Machines introduced a couple of new features not previously reported: an electric slide table for the Boy 35 E VH with vertical clamp, and integration of a Regloplas TCU with the Procan Alpha controller on a Boy XS (10 m.t.), enabling mold temperatures to be displayed and adjusted on the press control screen (via Euromap 82.1 protocol).
Chen Hsong is offering several new lines of machines, not all of which were at the show. The Jetmaster MK6 line of servohydraulic toggle presses comes in 88 to 668 m.t. The clamp, base, and injection blowing machine unit have all been redesigned and beefed up. Also redesigned is the Jetmaster Large SVP/2 series from 650 to 3000 m.t. New Evolution MK6e servohydraulic toggles (90 to 650 m.t.) are a lower-cost version said to be suitable for 80% of the market. The powerpack has been downsized somewhat, so these machines are not optimal for high-volume or high-torque production. There’s also a smaller new low-cost line, Focus SVP/2 from 20 to 60 m.t. At the higher-performance end is the new Speed series of servohydraulic toggles (128 to 468 m.t.) with a “top-of-the-line,” high-response servomotor for ultra-high-speed injection. The related new Speed-Pack series (260 to 470 m.t.) has longer screws, up to 26:1 L/D. Finally, a new all-electric series is the Spark line from 100 to 230 m.t., boasting a more compact and more open design.
Fanuc has a new standard execution for medical Roboshot machines, including such features as stainless-steel construction, special screws, HEPA filter, and new “bush-less” tiebars.
JSW introduced its patented SOFIT foam injection technology. It involves injecting nitrogen gas into the barrel in a decompression zone after the melting zone and before the metering/compression zone. A special screw and barrel are required, but a cost-saving feature is the ability to feed nitrogen directly from a storage tank via a pressure-reducing valve, with no need for a high-pressure metering pump.
KraussMaffei showed the new Netstal Elios 4500 (450 m.t.) high-speed, hybrid toggle press. The series was launched at NPE2018 with a 750-tonner, which is now supplemented by models of 450, 550, and 650 m.t. Also new was a 21.5-in. multi-touch display on the KM CX 80 hydraulic machine with a PLC control based on the KM MC6.