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Surface appearance, Take One: Piano-black PC/ABS parts with no painting

MPW caught up with French company RocTool at December’s Euromold trade show in Frankfurt, where the company came to draw attention to the new trick—injection molding—it has taught its inductive heating system.

RocTool emerged almost a decade ago at the JEC composites show in France, and until recently its technology for rapidly heating a mold’s surface to high temperatures using an inductive heating method patented by the firm has seen use only in some composite plastics processing.

But Matt Boulanger, the company’s business development manager, told MPW at Euromold that the company has optimized its technology for the injection molding market, where it sees great potential and in which interest already is high. Indeed, the week after Euromold, Boulanger started a multicity tour of the U.S., visiting potential customers interested specifically in what the technology could mean for injection molding. (For more on the firm, a good start is our June 2004 issue, p. 48, or search our website.)


Top photo: A Cage System is shown attached to the rear of an injection
molding machine.

Above: RocTool bets its mold heating technology will attract processors of parts requiring a great surface finish.


What it could bring to molders, said Boulanger, is the ability to process very high-quality parts of very high-temperature materials with very thin walls with very tight control of temperatures, so that in many cases there is no need for painting or coating parts after molding. The key is that the Cage System, as RocTool’s mold heating technology is known, only heats the surface of a mold, but does it very rapidly. Because only the surface of the mold is heated, cooling also can be done rapidly. The combination of the two helps prevent warpage and makes for better surface appearance. “We’ve molded PEI (polyetherimide, a very viscous thermoplastic) parts at just 1-mm thickness but with good surface appearance,” he said. No mold preheating is necessary, and molding machine pressure typically can be reduced by up to 30%, he added. 

At the firm’s Euromold stand he showed MPW two automotive interior parts, molded on the same mold but with one heated/cooled via RocTool’s Cage and the other using standard technology. Both parts were molded with a single gate. The part formed on a Cage-heated mold more accurately reflected the mold’s surface, with the part matte where it was supposed to be and glossy where it was intended. The other part’s matte-like appearance wasn’t very matte at all. “Tier Ones and OEMs see the chance for better surface quality,” Boulanger said.

“The tool design has to be optimized” to work with the Cage system, Boulanger notes, especially with regard to where cooling lines need to be placed and what sort of steel should be used. The method of attaching a Cage system to an injection mold, so that the mold is inductively heated, also is part of RocTool’s intellectual property. So far there appears to be about a 10-second cycle-time penalty when switching from an established mold to one heated via RocTool’s Cage, so clearly the technology will not see use in swift-cycling packaging applications. Current licensees of the technology include two French molders, Group Dedienne Plasturgie (Dedienne) and Plastivaloire (PVL), Europe’s largest molder of television frames. Automotive parts processor Visteon was the first to show interest in the injection molding technology and had an exclusive license for a short time, as did Didienne, but the exclusivity of both has expired.

Last October RocTool displayed the process on a Billion injection molding machine at Pôle Européen de la Plasturgie (PEP), a French technology center in Oyonnax, the center of the country’s processing industry. Boulanger showed MPW video of the event, attended by 250; presenters included experts from Dow Chemical, DuPont, and PVL. PVL showed attendees large, glossy, ‘piano-black’ PC/ABS frames it molded, and did not need to paint, which met customers’ requirements. He said Dow, DuPont, and other resin suppliers already have shown interest in developing materials specifically for the process. Boulanger added that RocTool is keen this year to find a similar technology center in the U.S. where its technology can be demonstrated, but where its IP is guaranteed protection. The firm also has contacted the Society of the Plastics Industry, asking after space at the association’s NPE 2009 exhibition in Chicago in June. The firm currently is recruiting a sales manager for North America. 
      
On the business end, RocTool can sell a test license to a processor and help it make a prototype/pre-series mold equipped with the Cage heating system. Once the mold and process are optimized, the processor then can acquire a full production license. “We want to license to good processors,” Boulanger stated.—[email protected]

Click here to read about another outfit who makes the same claim.

New molds from StackTeck lighten already lightweight parts even further

Canada’s StackTeck, a manufacturer of specialty, high-production molds, announced a new patent-pending technology called TRIM (Thin Recess Injection Molding) for light-weighting injection molded parts. The announcement was made in a presentation, ‘Plastic Part Design and Prototyping for IML Applications,’ by Jordan Robertson, StackTeck’s general sales manager, at the IMLCon ’08 North America conference held in Phoenix, AZ, on Oct. 22-24. MPW attended the event.



New molding technology from StackTeck is said to help trim even more weight from thin-walled parts by achieving wall length/thickness ratios greater than 500 with normal thin-wall injection speeds and pressure.


TRIM involves both the design and processing of a part. Conventional thin-wall part design normally assumes a maximum, low length/average wall thickness (L/T) ratio of 300. Using TRIM, StackTeck has demonstrated—via a 32-oz. rectangular container design—that large areas of the part can be thinned out so that an L/T ratio greater than 500 can be achieved. Depending on part shape and design, total part weight savings can be on the order of 20-40%.

StackTeck’s president, Randy Yakimishyn, said in a prepared statement, “Our customers are telling us that light-weighting is more important than ever, and so we are continuing to advance to the forefront of this technology. At this point, we believe that we can achieve part weights that will make injection molding much more competitive against thermoforming, while maintaining key functional features such as the tamper-evident rim on a container and high top-load compression strength.”

The prototype parts the company molded had a flow length of 5.74 inches (14.57 cm) and, with the recess areas covering half of the part’s side wall and bottom, a panel thickness of 0.011 inch (0.28 mm) was achieved. The injection speed and pressure used to fill the part were normal by thin-wall packaging standards, said Robertson, and StackTeck expects thin-wall molders can adopt this technology on their existing injection molding machines. This appears to be the biggest news of the development; L/T ratios of greater than 300 have been achieved before, including by StackTeck, but these have always involved machines able to generate tremendous speed and pressure.

A fill time of 0.2 seconds was achieved at a moderate fill pressure, using a 35 MFI polypropylene supplied by LyondellBasell. “Designing this part took a huge amount of flow modeling,” Robertson pointed out in his presentation. “With wall thickness that is one-half the standard thickness and covers one-half of the surface area of the part, we expected to have holes, but the model told us we wouldn’t—and we didn’t,” he said. The TRIM technology is being showcased on StackTeck’s inmold labeling pilot cell at the company’s facility just north of Toronto International Airport, using a 330-tonne injection molding machine. The IML pilot cell is a joint effort by StackTeck, Netstal, and CBW Automation to provide a prototyping and pilot program vehicle to the industry for IML applications.—[email protected]

Unilever margarine tub produced using MuCell process wins award

The Unilever 500g Rama margarine tub has been awarded the 2008 Deutscher Verpackungs Preis (German Packaging Award) and a WorldStar Packaging Award. The innovative tub design was developed by Veriplast Solutions and uses Veriplast’s super light injection molding technology (SLIM), which combines the MuCell microcellular foaming process with Veriplast’s Extra Slim Label, an innovative down-gauged inmold label.



The Rama 500g margarine tub is produced using Veriplast’s SLIM (super light injection molding) process, which relies on MuCell microcellular foaming from Trexel for weight reduction without loss of quality in the molded tub.


“The success of the SLIM program is a credit to Veriplast and Unilever who were able to understand the new design paradigms for thin-wall molding that become available through the MuCell process and to put them into effect,” says David Bernstein, president of Trexel.

SLIM technology uses MuCell, which involves the use of precisely metered quantities of atmospheric gases (nitrogen or CO2) in the injection molding process to create millions of nearly invisible micro cells in the end product. The gas nucleates cells during injection and allows the thin-wall cavities to be filled using reduced pressure and clamp tonnage, which permits additional thin walling. The micro cells replace their equivalent volume of plastic, resulting in a cumulative reduction of up to 10% in packaging weight without any perceptible difference in the final tub quality. Veriplast combines this with its own Extra Slim Label technology, which is significantly thinner than the market standard and provides an additional environmental benefit by reducing the CO2 footprint 30% compared to standard labels.

SLIM technology provides outstanding benefits in terms of packaging weight reduction and carbon footprint reduction. As a result, SLIM customers in Europe can save additional money by reducing Eco Tax costs. For example, in Germany, for a standard 15g tub, the 10% weight reduction obtained thanks to SLIM is a E200,000 ($265,248) savings in Eco Tax for every 100 million tubs.—[email protected]

Core-back/MuCell pairing adds strength but takes out weight for automakers

Trexel Inc. (Woburn, MA), inventor of the MuCell microcellular foaming process, and Engel North America (York, PA), a maker of injection molding machinery, are collaborating to develop and commercialize the injection/expansion molding process known as core-back using MuCell.

Core-back expansion molding has shown the potential to produce structural applications that feature dramatic weight savings, derived from the ability to redesign parts based on high density reductions (expansion of 50% or more), and resulting in increased stiffness-to-weight ratios.

MuCell enables the production of extremely high-quality plastic parts using precisely metered quantities of atmospheric gases (nitrogen or CO2) to create millions of nearly invisible micro cells in the end product. The creation of these microcellular structures brings a wide array of benefits, including reduced weight, material usage, and production costs, according to Trexel.


Top: Engel offers the only two-platen injection molding machine that has no contact with the tiebars, allowing frictionless movement to better control speed and precision. Botttom: Molten resin infused with a supercritical fluid foaming agent via the MuCell process is injected into a thin mold, where it expands quickly to fill the mold (left). After a certain period of time, the back of the mold is partially extracted (core back) to form the multilayer structure that can be much thicker, but less dense (right).



Advances in core-back technology are being made to help automakers realize significant weight reductions to improve fuel economy. For example, recent industrial trials announced by Mazda using MuCell have demonstrated the capability to mold parts with weight reductions of up to 30%, and the company announced it will begin using the technology on 2011 model year cars.

In core-back expansion molding, once the foamed resin has filled the mold, the volume of the mold is increased, causing the foam to expand. This results in stiffer plastic parts, with low density and good rigidity, which can be made with less resin. Through a series of industry trials, the combination of these two processes has demonstrated the possibility of redesigning parts in order to achieve dramatic weight savings in structural applications like IP retainers and door panel liners. But Trexel and Engel officials say the process combination is potentially applicable to a wide range of automotive applications.

“When you combine core-back and the MuCell process, you can essentially saturate the polymer with SCF, or gas in its supercritical state, while keeping the mold closed under pressure, and then precisely open the mold to get maximum expansion,” says David Bernstein, president of Trexel. “You get a much thicker part, but one that is much less dense—as much as 75%."

To succeed with core-back, precision molding machine technology is needed. Engel’s duo 1000-ton machine reportedly provides the ability to precisely control both position and clamp force by using its patented design concept for two-platen machines. “We offer the only two-platen injection molding machine that has no contact with the tiebars, allowing frictionless movement to better control speed and precision,” says Steve Braig, president of Engel’s North American operations.

Engel’s duo machines also feature a patented Platen Parallelism Control system. This allows users to control all four corners of the mold’s positioning individually, which, when using the core-back process, allows the tool to be opened for the material expansion part of the process with complete precision. “As a result, we can achieve the necessary precision for running the combined process and achieving dimensionally accurate results,” says Braig.

Bernstein adds, "Core-back technology is being given an entirely new purpose with the MuCell process, and we see a major quality and cost-savings opportunity for our customers.”—[email protected]

Polymer Corp. acquired by management and Prospect Partners LLC


The sale came as North American Fund, which had owned Polymer since 1997, was approaching the end of its term. The additional funding from Prospect Partners enables Polymer to aggressively execute growth strategies through internal development as well as through strategic alliances and acquisitions.

“This transaction is exciting for Polymer’s customers and employees,” says Bob Underwood, Polymer’s (and soon Prospect’s) president and CEO. “We had a great run with North American’s backing. At this phase of our business, we sought a partner that could help us continue to expand upon the strong company we have built.”

Founded in 1970, Polymer produces plastic parts and assemblies for a diverse nationwide group of blue-chip companies, primarily in three niche market segments: medical equipment and instruments; firearms components and accessories; and defense/security/aerospace. The company’s customers include GE Healthcare, Philips, Siemens, Smith & Wesson, Savage Arms, Browning/Winchester, Raytheon, Cobham, Teledyne Technologies, and Varian Semiconductor Equipment.

Underwood explains that when the original owners of Polymer Corp.—two brothers—were killed in a plane crash in 1996, the widows wanted to keep the company a going concern. North American Fund bought it in 1997, and Underwood, who was with North American Fund, was brought in to run the firm. “They worked with the company to grow it, and acquired a fairly small injection molding operation in Massachusetts in 2000,” says Underwood. “Casting was really low volumes and we needed a way to service the transition into injection molding when the volumes grew. Over time we integrated the operations and became a full-service company with multiple process capabilities, which has become a real strength to the business.”

Polymer Corp. also serves other industrial companies with demanding applications, and works with its customers through the complete product life cycle, employing a variety of custom high-precision production processes, such as stereolithographic rapid prototyping, liquid resin casting, injection molding, and machining of plastic components.

Its Gun Valley Molders division is a leading producer of synthetic gunstocks, recoil pads, and other firearms components and accessories. Another division, Polymer Marine, is a respected producer of components, housings, and assemblies used under water in defense, oceanographic, and offshore applications. Underwood notes that the three-pronged approach to its niche markets works well for the company. “They are all on different business cycles, and that’s important, as is our diversification,” he says.—[email protected]

Nanotechnology: Bayer starts work on world’s largest carbon nanotube plant

UPDATED—Bayer MaterialScience (BMS; Leverkusen, Germany) is expanding the commercial production of carbon nanotubes (CNT) it began in 2005, initiating construction on a €22 million plant in Leverkusen, which will have annual capacity of 200 tons (video here). Although that number seems small in the scale of most chemical and plastics production sites, BMS says its Innovationsallianz CNT consortium will represent the largest CNT plant in the world.



Dr. Wolfgang Plischke, the Board member responsible for research, and Thomas Rachel, Parliamentary State Secretary at the Federal Ministry of Education and Research (BMBF), with a model and a sample of carbon nanotubes.

BMS’s Katharina Jansen told MPW that the goal is for the facility to be finished by this summer, with production continuing at the company’s original pilot plant in Laufenberg, Germany, which has a capacity of 60 tons/yr. BMS is bullish on CNT’s future, citing forecasts that the global market for CNTs, which BMS markets as Baytubes, will grow by 25%/yr, with annual sales in 10 years expected to reach $2 billion.

The high cost of CNTs has partially restricted their broader adoption, with that cost structure supported by the lack of production scale—a scenario which could change with the new capacity. “It is fair to expect decreasing price levels for multi-wall-nanotubes as capacities and their utilization increases,” Jansen said, adding BMS cannot supply detailed figures. Jansen did say that today’s prices allow industrial applications and therefore meet current market requirements.

The Innovationsallianz CNT “Innovation Alliance” is supported by the German Federal Ministry for Education and Research (BMBF) and has more than 70 industry and science partners. Innovationsallianz CNT will invest a total of €80 million in research and development, with half that figure coming from the German government’s BMBF. Germany has created ambitious goals to reduce energy consumption, and it believes CNTs can help it achieve those targets by its self-imposed 2020 deadline.

Utilizing a proprietary catalytic process that’s housed in a reactor with elevated temperatures, BMS derives carbon nanotubes from a carbon-hydrogen gas mixture, according to Jansen. 

Commercially, Baytubes, which exhibit outstanding mechanical properties as well as thermal and electrical conductivity, have been added in small amounts to rotor blades for wind turbines, lightweight transport containers, and sports equipment. The combination of strength and conductivity is viewed as a means to improve battery technologies while reducing weight in a variety of products.—[email protected] 

In Brief

Improved R-PET sheet

One of the world’s largest suppliers of PET, Invista, now offers thermoformers a sheet that contains up to 25% post-consumer recycled PET(R-PET). The supplier says the R-PET content of the Performa-R sheet has no effect on the material’s color, clarity, and processability.

Berry acquires Erie

Berry Plastics Corp. (Evansville, IN) acquired the assets of Erie Plastics (Corry, PA), which was forced to file for bankruptcy protection on Sept. 29, 2008 after a customer, P&G, took its substantial business elsewhere. Berry plans to close the Erie site.

Bullish on green resins

Demand for plastics based on renewable materials is expected to grow 7.1% annually to $4.0 billion, or 1.75 billion lb in 2012, according to a new study released by The Freedonia Group Inc., a Cleveland-based industry research firm. Best opportunities are anticipated in packaging due to increased availability and competitiveness of materials such as polylactic acid (PLA).—[email protected]

Names in the news

Dave Lawrence, formerly president of Milacron’s D-M-E business, is now CEO at Milacron following the retirement of Ron Brown.

James Rogers, president of Eastman Chemical Co., will become president and CEO next May. Brian Ferguson, chairman and CEO since 2002, will then serve as executive chairman.

At PS and PE supplier Nova Chemicals, Chris Pappas, president and COO, becomes CEO next May when current CEO Jeff Lipton retires.

Additives supplier Chemtura named Craig Rogerson its new chairman, president and CEO, following the departure of
Bob Wood, who held these jobs since Chemtura was formed in 2005 from the Crompton/Great Lakes Chemical merger.—[email protected]

Pricing summary: Steep declines don’t draw

Spot polyethylene (PE) demand and prices rose a few cents in early December according to trading platform, The Plastics Exchange (TPE), with brokers and distributors wading into a market whose prices were off 60% from their summer peak. TPE says the broader market acknowledgement that a floor had been reach in spot prices prompted greater activity in the market. In contract prices early last month, rates had fallen, with speculation that there might be more decreases on the table.

Following a series of production cuts, TPE said only the most efficient polypropylene reactors were operating, with widespec availability extremely limited, forcing many to buy generic-prime PP.

Last month PE prices drifted lower in Asia, according to Polymerupdate.com, with little change expected this month, as business slowdowns or closures for the Chinese Lunar holidays, to begin Jan. 26, will further weaken demand. The story was similar for PP, with processors showing little interest even as prices had fallen. PS buyers across Asia remained convinced that further price declines would come, reported Polymerupdate. In Europe, the firm said last month saw further declines in prices of most plastics, contract and spot, but even then demand was not sparked.—[email protected]

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Machining center design simplifies cell creation

Interchangeable pallets and a cell controller allow different machining centers to be easily integrated into a single cell in a new flexible manufacturing system. Makino says it can combine 5-axis machining centers with 4-axis machines into automated cells because its machines have a similar size and interchangeable pallets. At last fall’s IMTS, Makino featured a cell with a D500       5-axis vertical machining center and an a51 horizontal machining center, with the machines sharing the same 400-mm standard pallet, allowing them to be integrated into a single machining cell.

The company’s Makino Machining Complex (MMC) features automated modular material handling that can link Makino machining centers with pallet loaders and operators. The cell’s 5-axis component is Makino’s new D500 vertical machining center, which contains ultrahigh-torque DD motors for superior acceleration.

Makino Inc., Mason, OH, U.S.A.; +1 513-671-3800; www.makino.com