NPE 2000 Showcase - Gas Assist: Gas in the Mold Finds New UsesNPE 2000 Showcase - Gas Assist: Gas in the Mold Finds New Uses

Gas assistas a processis obviously here tostay. Most interesting now are the new ways OEMs are deliveringand inserting gas in the mold, each designed to meet differentgoals.

GasAssist

Cinpres formally introduced its patented electrically actuatedgas nozzle, an ideal fit for all-electric molding machines (seephoto, right). In fact, Cinpres ran live demos of the nozzle ona 200-ton Ube Ultima UN Series all-electric press equipped withits gas-assist equipment.

A machine-mounted camera let show-goers see through a glass-walledmold to view how gas is introduced into the mold and how it canhelp the molding process. The new nozzle retains the featuresof Cinpres' retractable nozzles, which are designed for blockage-freehigh gas flow. Controls are fully integrated into the CinpresFull Shot control unit.

Cinpres also chose NPE as the venue to premiere live demonstrationsof the Scorim melt manipulation process. Scorim is designed tocontrol melt in the cavity to enhance material performance properties. The Cinpres Nitrogenerator also was on display. It combines aninput feed air compressor, a PSA-type nitrogen generator, andan air amplifier in a single, compact unit.

Incoe formally debuted External Gas Molding (EGM) technologyat the show. Incoe is licensed by Asahi Chemical of Japan to useand sell the technology in North America. With the process, materialsare injected with no application of packing pressure. Gas is injectedvia a porous metal insert, gas pin, or poppet through the coreside of the mold, typically at less than 100 psi, not into butonto the melt, blanketing the entire sealed area or selected areaof the part (see photo, left). Gas pressure is maintained as thepart cools, then is vented. The advantages presented by EGM'sstress-free molding technology are numerous:

Incoe demonstrated the EGM process in the Sandretto booth.A Sandretto Series Nine produced parts like those pictured atleft to highlight the process's ability to improve a part's structuralintegrity and aesthetics. NPE also marked the debut of the SeriesNine high-speed toggle clamp machines (75 to 550 tons).

Over in the Alliance Gas Systems booth, that company announcedthe development of a new gas-assist processing support system.Combining technological forces with Rix Industries, based in Benicia,CA, Alliance Gas Systems is providing what it says is the firstportable nitrogen generator specifically designed to meet theneeds of injection molding gas-assist applications.

The system is called the Alliance generator and will be manufacturedby Rix. It's a self-contained nitrogen generator that produces95 to 99.5 percent purity dry inert gas from atmospheric feedair. Three high-pressure models are available (3000, 6000, and8000 psig) with up to 10 scfm.

The system consists of a membrane module to produce the nitrogen,and an oil-free compressor and secondary intensification unitto generate the desired pressures. All components are mountedon a small skid with enclosure and controls. Operation requiresonly shop air and an electrical connection.

Battenfeld demonstrated its Airmould gas-assist technologymolding drawer fronts in its remarkable display of multimoldingversatility on a 500-ton hydraulic machine. The system featuredBattenfeld's mobile, touch-screen Airmould control unit designedfor user-friendly convenience. Among the control system's manyoptions is onboard storage of up to 99 data records. Systems withup to eight pressure control modules can be graphically displayed.

Two new nitrogen generators were among several new productsintroduced by Gain Technologies at NPE. Model GT-N2G-B is a 5-scfmunit; Model GT-N2G-C is a 10-scfm unit. Both models provide continuous,high-volume, clean, dry, oil-free nitrogen. They include a membranemodule to produce the nitrogen and air-driven intensificationto eliminate the chronic problem of oil-contaminated nitrogen.Air is supplied from a compressed air source that can be storedfor use in multiple gas-assist installations at up to 2500 psigand with up to 99.5 percent purity. Each unit requires only twoor three air connections (depending on model), and the 5-scfmmodel can be upgraded to 10 scfm.

Also from Gain was a new automatic shutoff nozzle. Engineeredspecifically for gas-assist molding, the nozzle installs betweenthe injection nozzle and tip. It can be used with a variety offilled and unfilled resins over a range of temperatures and fitsmost injection nozzle threads. It requires two heater bands controlledas separate zones for optimum temperature control, and does notneed to be removed for most conventional molding applications.

The final offering in the Gain booth was the GT-PIU-1A pressureintensification unit. It's a portable, air-driven machine thatrequires no electric power to provide high-pressure gas. Thisrelatively simple unit is reportedly easy to operate, requiresone air connection, and can provide gas nitrogen at 6000 to 10,000psig with the turn of a lever. It has high-pressure storage capacityand two high-pressure outlet ports, each independently controlledfor connection to Gain's Satellite gas controllers.

Bauer Plastics Technology Group, a gas assist injection moldingveteran, showed its line of nitrogen generation and injectioncontrol systems. The generator provides nitrogen up to 99.9 percentpure and delivers at pressures up to 6000 psi. On the controlside is a unit that can coordinate delivery of gas to as manyas four cavities simultaneously.