Plastics Technology

JUL 2018

Plastics Technology - Dedicated to improving Plastics Processing.

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Another interesting devel- opment was highlighted by W. Muller USA (mullerheads.com). The company has found that plasma spray coating of amorphous metal onto the flow channels of its extru- sion blow molding heads greatly speeds color changes. According to Jens Schlueter, general manager, the coating penetrates the surface of the steel and reduces the tendency of plastic to stick to the metal. Because the plasma is a gas-phase process, it penetrates even the smallest flow channels in the head. The coating was tested at a customer in the U.S. who has two identical shuttle machines in two different plants, both with Muller heads, one plasma coated and one head uncoated. In molding 1-gal HDPE jugs with a view stripe, the coated head required a total of 45 min to make the transition from blue to red and back to blue. The uncoated head required 75 min to make the same transition, Schlueter reports. He says the coating adds 10-15% to the cost of the head. 3D PRINTING LSR Distributor RDAbbott, (rdabbott.com) showed off a system for 3D printing with LSR, developed by Dow Silicones (previously Dow Corning), Midland, Mich. (consumer.dow.com), and German RepRap, a maker of industrial 3D printers (germanreprap.com). Called Liquid Additive Manufacturing (LAM), the system injects liquid A and B components from two pressurized tubes into a pump that maintains a 1:1 ratio. The pump feeds a head under x-y motion control, which and lays down a continuous bead, similar to FDM or FFF-style 3D printers. The system deposits layers as thin as 0.2 to 0. 35 mm thick, which are fully cured by a heat lamp, a whole layer at a time. The system uses Dow's Evolv3D LC 3335 LSR material, which produces a 44 Shore A hardness without post-cure and 46A with post-cure. The LAM 3D printer reportedly produces parts with 100% of the tear strength of injection molded samples, 90% of their tensile strength and hardness, and 85% of their elongation. Applications in development include honeycomb custom orthotic shoe soles. The patent-pending printer was introduced last year; it can print at 10 to 150 mm/sec. Dow is developing additional grades in other Shore hard- nesses, expected later in the year. FILM PROCESSOR'S SPENDING SPREE In extrusion, a leading PE film pro- cessor grabbed the biggest headlines. At NPE2018, Sigma Plastics Group (sigmaplasticsgroup.com), Lyndhurst, N.J, closed deals on 13 new film lines and four recycling systems. The firm said six new Optimex FFS lines it ordered from Windmoeller & Hoelscher (whcorp.com) will be up and running at its Republic Bags plant by the end of the summer, producing blown film for form-fill-seal sacks. This installation marks Sigma's first foray into the FFS market. The lines will produce about 45 million lb/yr of film, printed and gusseted. Meanwhile, Sigma's McNeeley Plastics plant has ordered two W&H Varex II blown film lines—a three-layer and a five-layer system. The latter will be equipped with W&H's Turboclean resin-purging and quick-changeover system and a Filmatic S winder with reverse-wind capability. This investment will support McNeely's expanding business in converter-grade films. In early May, Sigma started up a five-layer Varex II line at its ISOFlex plant. Sigma also announced it has ordered two high-output five-layer polyolefin-dedicated (POD) lines from Reifenhauser for its BJK plant, both equipped with the machine builder's Ultra Cool IBC and Ultra Flat patented in-line flattening system. Sigma also bought another two lines from Reifenhauser (reifenhauserinc.com) for its Allied Extruders division: a three-layer high-output system and a five-layer POD line. Both lines will also be equipped with Ultra Cool and Ultra Flat technology. Sigma also announced it had bought three Davis-Standard film lines: one 2.5-meter cast hygiene-film line and two five-layer agricul- tural blown stretch-film lines. The cast hygiene line is the second of its kind purchased by Sigma in the last three years. It will be engineered for A/B/A structures with in-line printing capabilities. The five-layer New plasma metal coating of flow channels in W. Mueller's extrusion blow molding heads allows as much as 40% faster color changes at modest extra cost. Jomar injection-blow molded PC LED bulbs with high cosmetic quality said to be unprecedented for this process. 16 JULY 2018 Plastics Technology PTonline.com N P E 2 0 1 8 F I R S T R E P O R T Close -Up On Technolog y

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