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Toshiba Opens Service Center in Mexico

By: Matthew H. Naitove 17. September 2014

Another indicator of the growing importance of Mexico to North American plastics manufacturing is the recent opening of the first Mexican service center by Toshiba Machine Co. America, based in Elk Grove Village, Ill. Located in the Nippon Express Guanajuato Logistics Center in Puerto Interior, Silao, Guanajuato, the new facility offers local service and support to injection molding and die casting customers throughout the country. Mexico has benefited from the “reshoring” trend as a competitive counterbalance to manufacturing in the Far East. “This is a thriving market for us,” says Toshiba Machine America general manager Tom McKevitt. Manager of the new service center is Robert Kinzel. Contact: +52 472-748-5400.

Helping PET Blow Molders Save Energy & Material

By: Matthew H. Naitove 17. September 2014

Two projects are under way at Plastic Technologies, Inc. (PTI), Holland, Ohio, a leader in PET package development. One is intended to help PET bottle makers reduce their energy costs by designing custom plans for processors. This involves a careful analysis of all bottle manufacturing stages at the customer. This includes preform and bottle production, supply and quality of compressed air, machine conditions and capabilities, blowing cycle review, oven setup, process development, and package performance validation. “Companies go out of their way to drive weight out of bottles, but they often overlook the significant amount of energy waste that occurs when running the equipment,” says Donald Miller, v.p. of technical services. “Depending on how inefficient energy usage is, this can be a gold mine of ‘found money’ for the company.”

 

A particular focus of PTI’s energy review is compressed-air usage. Miller says, “The key to creating a successful energy reduction program is to consider air delivery and air demand requirements at the same time. In the past, companies have tended to focus on these as separate areas and not in concert with one another. Using a systems approach is the key to optimizing operational improvements.”

 

Another new initiative by PTI is becoming the exclusive U.S. representative for several PET processing technologies developed by Toyo Seikan Co., Ltd. of Tokyo. One of the areas that the two companies will be working together on is new foamed PET bottle technology which produces lightweight containers with good barrier attributes and unusual visual and tactile properties. The companies will unveil more details about the new technology—and its potential impact on beverage packaging in the U.S.—in the coming months. They also will reveal other PET technologies to be marketed here.

VW Explores Thermoplastic RTM

By: Matthew H. Naitove 5. September 2014

I recently posted news that BMW in Germany had installed a large vertical press from Engel to mold composite parts with liquid reactive thermoset resins. Now, it appears that Volkswagen in Germany is also pursuing liquid reactive molding of composites, but in this case with thermoplastics.

KraussMaffei (U.S. office in Florence, Ky.) is developing equipment systems for thermoplastic RTM, involving conversion of liquid caprolactam monomer into nylon 6. Because of the low-viscosity of molten caprolactam, it can impregnate dry fabric reinforcements in a mold, which would be impossible with viscous nylon in its polymerized state. KM has pursued what it has dubbed “T-RTM” using one of its own PUR metering machines paired with a vertical-clamp, tilting mold carrier (introduced at K 2013). This equipment comes from the Composites/Surfaces Business Unit of the Reaction Process Machinery Div. at KM.

The first products made with KM’s T-RTM process are B-pillar reinforcement prototypes made at the FRP TechCenter of the Volkswagen Group Research Center in Wolfsburg, Germany. The project utilized caprolactam supplied by BASF SE (U.S. office in Wyandotte, Mich.). A special RimStar series metering machine was adapted specifically to the extremely low viscosity of caprolactam and was fitted with a special mixhead, high-performance axial pumps, and a fully electric temperature-control system.

FEA Software Predicts Material Response to Repeated Snap Fits

By: Matthew H. Naitove 22. August 2014

Designing parts with snap fits present a particular challenge because of the repeated cyclic loading and unloading. During such cycles, the viscoelastic nature of thermoplastic materials determines how the bouncing back to “normal” occurs—and how it varies with time over multiple stress-strain cycles.

 

That’s part of the challenge that faced Novo Nordisk of Copenhagen, Denmark, a world leader in insulin self-injection pens. These pens are small, but they are precision instruments with a number of complex parts that must work in perfect coordination. Some pens are durable, containing a replaceable drug cartridge, while disposable ones come pre-filled with a drug. Injection typically involves twisting a short needle onto the pen, turning a dial to the required dose, and pushing a button to deliver the medication under the skin. After a given number of doses is injected, either the cartridge is replaced (for a durable device) or the pen is discarded (if a disposable version). In either case, audible clicks occur at key stages of the procedure, reassuring patients that they are engaging the device correctly at each step. But every one of those reassuring clicks represents a challenge to the design engineers. So do the clicks the patient never hears—those that occur during assembly of the pens in production.

 

To integrity of their designs, Novo Nordisk’s Device Simulation department rely on computer simulation with Abaqus finite-element analysis (FEA) software from Simulia, an application of Dassault Systèmes of France (U.S. headquarters in Providence, R.I.). “Over a decade ago, I and my colleagues explored a number of commercial software codes,” says Torben Strøm Hansen, principal scientist in the Device R&D division of Novo Nordisk. “We chose Abaqus because it was a well-integrated solution that could model the nonlinear behavior of the fine details our designs correctly, including the high number of interfaces in contact.”

CAD model of insulin pen components. Gray and red parts snap fit onto the green part.

 

Besides modeling viscoelastic response to repeated snap fits over time, the designers had to predict the behavior of the materials in different environments, including elevated temperatures, even though the pens are assembled from different materials. And, some materials may contain carbon or glass fibers that show anisotropic behavior, which can be hard to predict. Even just sitting on a pharmacy shelf or in a consumer’s medicine cabinet, the materials are prone to creep and relaxation over time at rates that can vary with temperature.

Injection molded ratchet component from a medical device used by Novo Nordisk for a snap-fit benchmark study.

 

Hansen’s team at Novo Nordisk is now using the “parallel rheological framework” methodology available in Abaqus to model polymers’ nonlinear viscoelasticity with greater accuracy than before. The framework makes use of an arbitrary number of viscoelastic networks and an elastic equilibrium network to create a nonlinear model to predict and track changes in the internal structural networks of a polymer as it responds to repeated cyclic snap-fit loads. “Having material models incorporating time-dependent viscous behavior is very important for our work,” says Hansen. “We’re now able to simulate both creep and relaxation with Abaqus.” Since every type of polymer shows a different response to temperature, load, etc., the team continues to explore ways to identify the characteristics of different polymer networks.

 

Not only are such advanced models useful to designers in fine-tuning the latest insulin pen configuration, the data can help in manufacturing processes at the factory. “We have a process-simulating capability, through Autodesk Moldflow, for which Abaqus has an interface. This allows us to input the stress fields that result from the injection molding process right into our models. As a result, we have greater insight into our manufacturing process and are more able to design parts that have very low levels of residual stress in critical regions.”

BMW Ups Its Stake in Composites

By: Matthew H. Naitove 20. August 2014

BMW continues its exploration of large composite parts for lightweight automotive structures. It just installed a 3600-metric-ton model of the new v-duo vertical v-duo two-platen injection press from Engel Austria (U.S. office in York, Pa.), a smaller version of which was shown at K 2013 in Dusseldorf (see our January show report). The machine was delivered to BMW’s plant in Landshut, Germany, where it will be used to mold large structural elements from fiber composites using the HP-RTM (high-pressure RTM) process. This process injects liquid reactive components for thermosets (epoxy or polyurethane) or thermoplastics (caprolactam for in-situ polymerization into nylon 6) over a layup of dry reinforcing mats or fabrics. BMW plans to use the Engel press for thermoset composites, but would not specify the resin system.

 

The press has two slide tables to remove finished parts and insert fiber reinforcements. Engel notes that the machine has a much smaller weight, footprint, and height than typical vertical compression presses. The clamp unit is accessible from all four sides instead of just two. The press uses ecodrive servo-driven hydraulic pumps for energy efficiency, without any hydraulic accumulators.




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