Does Low Constant Pressure Injection Molding Work?

By Jan H. Schut

It could be the most unusual new development in injection molding in the past 20 years, developed by household products giant Procter & Gamble Co., Cincinnati, OH (us.pg.com). According to P&G patents, the technology consists of retrofitable controls and software for aluminum injection molds with pressure sensors and special cooling, which P&G claims increase productivity more than 50% on existing injection molding machines. P&G set up a subsidiary, Imflux Inc. (imflux.com), in May 2013 in Hamilton, OH, to develop and build the retrofits and aluminum molds and requires packaging suppliers to use them if they want to mold for P&G.

Productivity gains are in material savings, not faster cycle time. Imflux U.S. Pat. Applic. # 20160096303 says its proprietary control software and in-mold sensors “deliver a 20-25% average throughput benefit” on existing presses and tools. Using aluminum molds increases throughput another 20-25% because of aluminum’s high thermal conductivity. Imflux patents describe molds made of aluminum alloys like QC-10 from Arconic Inc., formerly part of Alcoa (www.arconic.com), which are 4.5 times more thermally conductive than tool steel (92.2 BTU/ft/hr/ft sq/F for QC-10 vs. 20.2 for P20 tool steel).

Cycle time for Imflux low pressure molding is reportedly roughly the same as for high pressure injection molding, but divided very differently. Where conventional high pressure injection molding spends about 10% of cycle time filling, 50% packing, and 40% cooling, Imflux technology spends 90% of cycle time filling, only 10% cooling (U.S. Pat. # 882829), and little or no time on pack and hold. P&G touted the Imflux technology loudly four years ago when it was introduced, but has said next to nothing about it since it went commercial.

Imflux says its low constant pressure injection molding with aluminum molds

increases throughput by more than 50% on the same size or smaller press
uses 25% less resin than conventional molding because of thinner walls
reduces cold runner volume by 50% (and doesn’t need hot runners)
can mold non-traditional part designs, not previously thought possible
can substitute lower cost materials in the same mold with better surface quality
uses melt temperatures below resin spec for new co-injection possibilities

THE IMFLUX BACK STORY

Imflux came out of an unusual 10-year period of outside collaboration and growth at P&G under high-profile CEO Alan George “A.G.” Lafley, from 2000 to 2010. Lafley, who has a Harvard M.B.A., brought Harvard-trained innovation consultants into P&G, proclaimed P&G “an innovation factory,” offered “innovation college” courses, and set up a FutureWorks division to incubate new technology. Imflux president and CEO, Nathan Estruth, and V.P. of Customer Operations, Jared Kline, both came out of P&G’s FutureWorks division.

P&G claims Imflux invented its low, constant pressure molding technology, but that’s not strictly true. It’s based on technology invented in the 1990s by Milko Guergov, president and founder of Intellimold/MGV Enterprises Inc., Ann Arbor, MI, and acquired by P&G around 2010. By 2012 P&G had registered the Intellimold trademark and process in Imflux’s name, but never marketed it as Intellimold. After P&G acquired Intellimold’s intellectual property, Guergov consulted with P&G to adapt his process to thin-wall packaging. Guergov’s name, spelled “Gergov” by P&G, is on several Imflux patents (U.S. Pat. # 8980146 and # 9481119) along with P&G inventors.

Guergov had previously sold his Intellimold patents and process in 2000 to Textron Automotive Co., which Guergov says used it commercially to injection mold parts ranging in size from small components to whole bumper fascia. The patents traveled a lot after that. Guergov’s U.S. Pat. # 6019918, for example, on “Gas-assisted injection molding with controlled internal melt pressure” was assigned in February 2000 to Guergov, then in May 2000 to Textron, then back to Guergov’s M&C Advanced Processes Inc. in December 2001 before Textron’s automotive trim division was acquired by Collins & Aikman Corp. in January 2002.

The patent was then assigned back to Textron in 2003, to Collins & Aikman in February 2005, and back to Guergov’s MGV Enterprises LLC in April 2005 ahead of Collins & Aikman’s Chapter 11 bankruptcy in May. By 2007, Collins and Aikman had gone out of business, and by 2008, Guergov had let Patent # 6019918 lapse by failing to pay the annual maintenance fee. By 2011, however, the patent had bounced back and belonged to P&G, which assigned it to Imflux in 2014.

P&G CEO Lafley, meantime, had retired in 2010, but was called back by P&G’s board for two more years as CEO, starting in May 2013, just as Imflux opened for business. In Lafley’s second stint as CEO he focused not on innovation but on productivity, which also suited Imflux. In October 2013, P&G CFO Jon Moeller told an analyst conference call that Imflux would save the company $150 million/year in material cost and $50 million/year in capital cost. At the same time “Advertising Age” indirectly quoted P&G’s recently replaced CEO Robert McDonald saying Imflux would save P&G a billion dollars a year by “using less plastic and different raw materials.”

In 2013 P&G’s Imflux got a 60% eight-year Ohio tax credit, reportedly worth about $2.6 million from the Ohio State Development Services Agency for investing $50 million in Imflux over the next eight years and creating 221 new jobs by December 31, 2016. Imflux, however, missed the job creation deadline. A photo of “The Imflux Team” on its website in June 2016 showed only around 70 employees. On December 20, 2016, Imflux’s CFO filed for a two-year extension to December 31, 2018. “The Imflux Team” photo on the company’s website in June 2017 shows around 122 employees, so jobs are growing, but more slowly than expected.

Imflux team

Imflux missed the deadline for an Ohio tax credit for creating 221 new jobs by Dec. 31, 2016 and got a two-year extension. “The Imflux Team” photo on its website in June 2016 showed around 70 employees and a year later only around 122, so jobs are growing more slowly than expected.

By 2017, Imflux’s website says its “current global operation (has) hundreds of installs across three continents.” The installations are presumably at P&G packaging suppliers. Two P&G subsidiaries that do their own injection molding, Braun GmbH and Gillette, may also use Imflux technology for thin wall molding because R&D employees of both Braun in Germany and Gillette in the U.K. are named on some Imflux patents.

Imflux also offers retrofits to outside customers in non-competing areas like medical and automotive and gives seminars in Hamilton on the technology – all under non-disclosure agreements. No outside users have been announced. P&G senior manager of global company communications, Jeff LeRoy, says Imflux customers are confidential and that which P&G brands use Imflux technology is considered proprietary.

HOW DOES IMFLUX LOW PRESSURE MOLDING WORK?

How did P&G convert the not-very-successful 20-year-old Intellimold process into a viable molding process for thin-walled packaging? Intellimold patents describe pressurizing molds with about 200 psi of shop air to control mold filling at constant low pressure. Imflux patents (U.S. Pat. # 8828291 and 9272452) describe molding at low constant pressure of 3000-6000 psi, which is 5-10 times lower than conventional injection pressures of 15,000-30,000 psi. What Intellimold and Imflux appear to have in common is control of mold filling based on maintaining constant pressure in the mold, not on achieving high injection speed.

Imflux’s patented control technology (U.S. Pat. #8980146 and #9321206) claims to alter injection pressure if plastic viscosity changes, so multiple cavities can be filled without short shots or flash. Imflux U.S. Patents # 9289933 and # 9481119 describe a “fluid pressure regulating valve and pressure relief valve” as part of this pressure control, while U.S. Pat. #8911228 describes a “non-naturally balanced feed system” for multi-cavity injection molds with different runner lengths.

The high thermal conductivity of aluminum molds combined with low molding pressure apparently allows co-injection with “more control over the relative velocities of the materials being introduced,” says Imflux patent application WO # 2013126667. The application describes flowing a very thin (0.1 mm) surface layer of a high strength polymer like EVOH or PP together with a layer of an environmentally friendly polymer like PLA, starch and/or postconsumer recycled plastic and achieving overall wall thickness of less than 0.5 mm.

US08591219

Aluminum molds often don’t have cooling lines. Imflux U.S. patent # 8591219, however, describes aluminum molds with fixed mold plates through which coolant flows. Coolant then goes through a condenser and is sprayed onto an upper mold surface.

Another Imflux patent describes a “simplified evaporative cooling system” (U.S. Pat. # 8591219) with cooling lines in a support plate and projections that allow mold cavities to snap in. U.S. Pat. Applic. # 20150064303 describes “simplified cooling with exotic cooling fluids” in channels in the mold support plate for high output injection molding of consumer products. Other patents describe using “hazardous, dangerous or expensive coolants.”

Imflux low pressure molding also apparently allows higher length/thickness ratios for thin wall molding. U.S. Pat. Applic. # 20130221575 on “Method for Operating a High Productivity Injection Molding Machine” shows low pressure molding of parts with up to 240 L/T vs. 100-200 L/T for high-pressure, conventional injection molding.

US20130221575

In U.S. Pat. Applic. # 20130221575, Figures 5A-5D show a cavity filled by conventional variable pressure injection molding. Figures 6A-6D show cross sections of a thin-wall injection mold cavity filled by Imflux’s constant pressure “high productivity” injection molding.

But analyzing the patents is all guesswork. Imflux technology remains a closely held secret known to dozens of major packaging companies and probably hundreds of processors under non-disclosure. Is it fully commercial? Is it working as well as P&G expected? Does it work with some polymers and not others? Is any company using it voluntarily or is it installed only at P&G subsidiaries and suppliers? Why hasn’t P&G presented actual production data?

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