K 2013 WRAP UP: EXTRUSION
Research & Development
Extrusion: Machinery & Equipment
Extrusion: New Technologies
Plastics: Technology Advances
Right-sized extrusion lines
Davis-Standard launched its dsX series of extrusion lines for smaller-volume applications at the K show. The first two products in this series are for extrusion coating and stretch film; a dsX medical tubing line will be available next year.
The new dsX flex-pack extrusion coating line (patent pending) provides converters and printers with a pre-engineered system that has the capabilities and flexibility needed to compete in a variety of rapidly-emerging application opportunities such as salted snack and noodle bags, toothpaste tubes, sachet packs personal care products, condiment packs, and stand-up pouches. Two layouts are available to accommodate almost any plant layout.
The optimized dsX s-tretch pre-stretch cast film extrusion line is claimed to be the first in-line pre-stretch system enabling customers to run thinner films at higher speeds, allowing stretch film providers to produce consistent, high-quality pre-stretch film with greater efficiency. The 2-meter wide line has the advantage of a lower footprint, yet allows for growth.
Since these systems are pre-engineered, they can be delivered in as little as six months.
Davis-Standard LLC (Pawcatuck, Conn.);
Auxiplast Inc. (Ste-Julie, Que.); 450-922-0282
High output film line
Hosokawa Alpine showed at K a five-layer blown film line equipped with its patented X-die with 400 mm diameter and a special triple lip high output V-ring. This line is capable of an output of up to 1,000 kg./hr. It was running a different structure each day of the show.
One example is a 90 micron polyethylene film that was blocked at the nip into a 180 micron sheet. This was then fed through Alpine’s TRIO (trim reduction and orientation) machine direction orientation (MDO) system and stretched by a ratio of 5.3 to 1 to a finished thickness of 34 microns. With conventional MDO, the edges of the film are still comparatively thick and about 8 inches edge trim is needed. With TRIO, the amount of edge trim is halved to about 4 inches.
Stretching makes the polyethylene film clear and stiff so that it can replace laminated polyester film in stand-up pouch applications. The big advantage is that the laminated PE/PE structure can be recycled.
To date, TRIO has been used in Europe for various specialized film applications. North American sales are expected in the near future.
Hosokawa Alpine American Inc. (Natick, Mass.);
High-speed extruder and roll stack
The packaging division of battenfeld-cincinnati showcased its high-speed extruder and new “Multi-Touch” roll stack, which can be delivered either as individual components or combined and integrated in complete extrusion lines. In contrast to conventional three-roll roll stacks, the Multi-Touch roll stack operates with a larger number of roll nips, thus achieving reliable cooling of the film on both sides.
The new roll stack is equipped with a two-roll roll stack for preliminary calibration and three, five or seven rolls for final calibration. The first rolls come with a larger diameter to minimize deflection; the rolls that follow are smaller to ensure the production of film with low tension and perfect flatness. Due to continuous roll contact, the company said the film has hardly any orientation and an extremely even thickness profile. In contrast to standard roll stacks, where film tolerance margins of 3% are the order of the day, Multi-Touch achieves an accuracy of +/- 1%. Film can be produced at high line speeds from a wide variety of material, including PS, PET, PP or EVA and co-extruded products.
For the PET industry, meanwhile, battenfeld-cincinnati unveiled its specialized single-screw extruder with an integrated compounding section for outputs between 500 and 1000 kg/h. By dispensing with preliminary material drying, the company said, the system uses up to 16% less energy.
battenfeld-cincinnati (McPherson, Kan.);
New screw design cuts energy usage
The new Evolution extruder line from Reifenhauser Inc. features an Energizer screw that “will avoid useless energy input, reduce energy consumption, and lower melt temperature by as much as 20°C without compromising melt quality or output,” said managing director Ulrich Reifenhauser.
The extruders, which will be available in 30 to 150 mm diameters with 30:1 L/D, require virtually no barrel cooling. Reifenhauser has devised a “smart air-management system” that diverts hot air from the extruder to the hopper to preheat the material. The extruders also feature new drive technology that will allow processors more flexibility to select motor type and motor-cooling method.
Reifenhauser also debuted the Mirex MT polishing-stack technology. The patent-pending unit allows for automatic, digital nip adjustment, even during production runs, eliminating the need for manual, trial-and-error nip adjustments that require the line be stopped. With no hydraulics, the Mirex MT is suited for clean rooms, the company said, and will be available in three designs, depending on application, film thickness, and production capacity.
Reifenhauser Inc. USA (Danvers, Mass.);
Flex Essentials Inc. (Caledon East, Ont.); 905-584-6369
Co-extrusion allows for reduced costs in raw materials
Milacron Extrusion Systems showcased the TP75 and the PAK250 with the Multi Pass Tank. The TP75, a counter-rotating intermeshing twin screw extruder, is well suited for profile, pipe and WPC production, the company said. The TP75 comes standard with an energy efficient AC motor and drive, and active screw oil cooling for precise process control. Available options include an environmentally friendly dry vacuum pump, tungsten screws, and matching barrel for reduced long term maintenance cost. The TP75 uses Milacron’s MOSAIC control system to provide advanced machine control. When combined with one or more twin or single screw models, the MOSAIC control system is capable of handling the control of extruders while supporting other equipment downstream within the system.
These features make the TP75 well suited for the production of co-extruded profiles, which utilize recycled and virgin materials. Milacron uses the TP twin parallel models in conjunction with its TC twin conical models to provide solutions for the co-extrusion profile market. Features include automated articulation of auxiliary machines to make the adjustments to different products easier, while utilizing its MOSAIC as a single point of control. For example, the technology in the co-extrusion system allows the combined machines to create product that features a pure outer layer and a recycled inner core at a rate of 1,360 Kg/hr while reducing waste.
The PAK250, meanwhile, is an extruder specific to the medical market. The most common product produced by this machine is flexible PVC for non-phthalate plasticizers. At the K show, the PAK250 was featured with the Multi Pass Tank (model HTMP-18-4) from partner Conair. The tank was used to produce flexible PVC medical tubing at a high rate of speed with a reduced
foot-print. The benefit of the Multi Pass Tank is the ability to reduce the stretch of the tubing during the extrusion process, Milacron said. Other key features include a 16-inch servo driven first pass wheel, a vacuum chamber with closed loop vacuum system, an ultra-violet water treatment system, and a stainless steel tank for easy maintenance and cleaning.
Milacron Extrusion Systems (Batavia, Ohio);
New single-screw series for PE and PP pipe extrusion
KraussMaffei Berstorff showcased the KME 60-41 B/R single-screw extruder series with a processing length of 41L/D.
With its actual processing length of 41L/D, the new series is ideally suited to high-performance PE- and PP-pipe extrusion, the company said. “When we were redeveloping this series, we incorporated elements from our 36D series, which has enjoyed significant success for some time and boasts customers from across the globe, and combined these elements with a new processing concept.
The screw has been designed to exploit the entire length for melting and homogenizing, the company said, thereby reducing the amount of stress to which the polymer is subjected, as well as ensuring that plasticization has a reduced impact on the material properties during the melting process. In addition, an improved combination of heating and cooling means that the barrel can ensure optimal heat dissipation. A filling opening that has been modified in terms of length and dimensions to accommodate the increased throughput guarantees linear throughput development across the entire speed range. The design of the spiral grooved bush provides low-impact material handling alongside feed stability. Long machine life is implicit in the new extruder series, with bi-metal barrels and optionally through-hardened grooved bushes imparting excellent wear-resistant properties.
The 41D series is available with 45, 60, 75, 90, 105 and 125 mm screw diameters.
KraussMaffei Corporation (Florence, Ky.);