Highlights of NPE2009 (According to Our Panel of Experts, That Is)
Additives and application solutions drew attention at NPE2009
EXPERT: Dr. Donald V. Rosato, sr. research analyst, plastics, technical insights, Frost & Sullivan (Concord, Mass.)
Extruded cable conduits and conductor rails for building and construction end uses are being produced from a market-leading, halogen-free, flame-retardant (FR), polycarbonate/acrylonitrile butadiene styrene (PC/ABS) blend, Bayblend FR 3030, from Bayer MaterialScience.
The PC/ABS resin blends offer a favorable combination of mechanical and thermal properties.
The material has good heat resistance, rigidity, dimensional stability, easy processing, as well as high toughness even at cold temperatures, and good color stability in indoor lighting. Bayblend FR 3030 used in this application has a Vicat/B 120 temperature-rating equivalent to 115C, a UL94 V-0 rating at 1.5 mm, and is halogen-free.
It also has good extrusion and vacuum-forming behavior. Plastics used in housings for electrical and electronics applications need to exhibit a combination of performances including high impact resistance, high stiffness, good dimensional stability, and compatibility with specific FR regulations.
To replace halogenated flame-retardants, some are turning to nanotechnology. NaturalNano Inc., a developer of advanced nanomaterials and additive technologies based on halloysite clay nanotubes, is developing a range of products with extended release properties including flame-retardants for furniture applications based on its family of Pleximer products.
The nanotubes, with their hollow structure, can be filled with additives to create a slow or extended release of the additive concentrate. For FR applications, the company believes it can develop flame-retardant compounds that would release only under extreme heat conditions.
NaturalNano believes that commercializing Pleximer with extended release capabilities is not only the next step in expanding their product offerings, but also is an important next stage in the evolutionary development of nanocomposites.
Less fragile than crystalline silicon (c-Si) solar cells, and less expensive to manufacture, the recently developed thin film solar cells (TFSC) — also referred to as thin film photovoltaic cells (TFPV) — by DuPont Photovoltaic Solutions are expected to grow at a faster rate than c-Si: from 10 per cent of the current market to about 40 per cent within the next 10 years.
TFSC may be either rigid or flexible. They are made by depositing one or more thin layers of photovoltaic material, using a variety of deposition methods, onto an array of thin substrates such as glass, metal (e.g., aluminum, stainless steel) or plastic (e.g., polyimide). Unlike c-Si, which have light-absorbing layers on the order of 200 to 350 microns thick, TFSCs have light-absorbing layers which range between a few nanometers to tens of micrometers.
These thin film cells use one of three major semiconductor materials: a-Si (amorphous silicon), CdTe (cadmium telluride), or CIGS (copper-indium-gallium selenide). Their electrical efficiency ranges between six per cent and 20 per cent, depending on the semiconductor. Thin film solar cells that make use of other photovoltaic materials, including organic solar cells and dye-sensitized solar cells (DSC), are also in development.
Doing more with less at NPE2009
EXPERT(S): Mark Bonifacio, principal of Bonifacio Consulting Services (Natick, Mass.)(Assisted by) John Thomas, associate at Bonifacio Consulting Services
CONTACT: firstname.lastname@example.org; Tel: 310-683-3257
Engel showcased an integrated energy calculator feature that displays energy consumption of individual machine motions (mold open/close, injection/holding pressure, and others), and then allows for optimization of the machine (motion) profile without affecting the cycle time. This feature on their new CC 200 controller claims to generate energy savings of 15 to 20 per cent.
Negri Bossi introduced their Janus line (160 to 900 tons) of hybrid machines that combine both hydraulic and electric motion technologies. Optimizing function and energy savings, direct drive servos run the mold clamping and screw rotation, and smart pump hydraulics run the inject, eject, and carriage movements. Their technology uses no ball screws in the injection or eject units, while allowing for multiple (overlap) movements, application flexibility, and (optional) accumulators for high speed injection.
Wittman Battenfeld’s new generation MicroSystem 50 production cell for microparts offers two clamping forces, two new sizes of injection units, and various add-on modules. Their combination of plasticizing screw feeding a plunger injection unit allows parts the size of one resin pellet (or smaller) to be produced with accuracy and repeatability.
Schottli AG (Germany) displayed a 96-cavity tool in the Sumitomo-Demag booth, running their “X-light screw cap” weighing one gram (a 30 to 40 per cent reduction over conventional caps) at an impressive three seconds.
The MGS Mfg. Group displayed a multi-component, multi-material medical device that they were getting ready launch as of show time. After more than a year of development, MGS produced the tool, and will also run the parts for their client. In addition to the whole package that MGS can offer, they also can produce bolt-on injection units that can be customized to specific applications or existing presses, as well as mounted on the platens or mold for either top or side injection. This allows the mold to be designed around the part, instead of being dictated by the limitations of a two-shot machine, helping to get to the most efficient system possible, in addition to lower investment cost, and added flexibility. Multi-component projects can now be done without purchasing a full multi-component machine that may or may not be utilized for other projects. This is especially critical for custom/contract molders.
Trends and how-to in extrusion
EXPERT: Allan L. Griff, consulting engineer (Bethesda, Md.)
With most processors not buying much new equipment, I’ve decided to be a maverick journalist and talk about extrusion trends on evidence at NPE2009, and directions and how to follow them.
It should never be forgotten that material — not equipment — is by far the major cost in most extrusion (power is a distant third). This means that anything that can save material is worth talking about. The show was full of devices that allow closer control of thickness (gear pumps, automatic die-lip adjustment, and better data acquisition systems to locate and help fix out-of-gauge problems), additives that can reduce material costs (including foams and filler/reinforcements), and both equipment and materials that can increase re-use of scrap, trim, and purchased recycle in ways that truly replace new material. Such equipment includes finer grinders, melt indexers, and
moisture testers. Resin-saving additives include compatibilizers, antioxidants, and chain extenders.
Increasing production rate always takes top headlines, as processors think that if they can make it faster, they can save money. Higher output rate isn’t always higher profit, however, as it may affect wall thickness control (more scrap, thicker aim to avoid service failure), and increase linear orientation, which affects physicals, forming behavior and post-extrusion shrinkage. Also, if you can’t sell more, making more lb./kg per hour might get the product to the customer faster, but won’t help the bottom line much, if at all.
Don’t confuse higher screw speed with higher production rate. A very fast screw in a smaller barrel can often produce as much as a slower, more conventional machine, and may even reduce degradation because of shorter residence time even at higher melt temperature. There may be feeding problems with some materials, however; also, be sure to compare output per unit investment at equivalent quality, rather than just output per inch of barrel size.
In cases where higher speed does lead to savings, static mixers will help in cases where mixing is the limit to rate. Remember that sometimes changing concentrate carriers, and/or using smaller particle sizes and/or a dispersing agent, can have similar effects.
This is not to say that there weren’t unusual extrusion applications at NPE2009. Two extrusion applications won awards for innovative product design: a filtration assembly that combined tiny lumen tubes in an extruded-net enclosure, and a “wrap” of UHMW-HDPE sheet to protect wooden pilings for piers and docks.
Further questions? I presented a 1-hour web-seminar on Extrusion at NPE for IDES-The Plastic Web on July 7, which is archived on the IDES site (www.ides.com) and may be accessed through their site at no charge. I would also be glad to reply to emails or phone calls related to this or any other extrusion question.
Fewer blow molding machines than at previous shows, but interesting applications
EXPERT: Ottmar Brandau, OB Plastics Consulting (Wasaga Beach, Ont.)
A noteworthy display of extrusion blow molding was Techne Technipack Engineering from Italy, which showed two large shuttle machines. The single shuttle System 10000-S900 produced 2.5-gallon multi-layer containers in three cavities.
More dramatic was the Advance Model 4-510 shuttle that uses a brand new concept to boost productivity. Previous Techne models had featured a head-to-cavity ratio of 1:1, while most double-sided machines from other manufacturers use a ratio of 1:2. The Advance model, however, has only one head to supply four cavities, giving it a 1:4 ratio. This is accomplished by having two separately controlled blow clamps on either side of the 5-head, moving them back and forth as they pick up parisons and then blow them. The all-electric machine has a dry cycle time of two seconds, and molded a 22-gram bottle at 8,000 bottles per hour in 20 cavities.
Bekum America Corporation uses a very different concept to boost output. Previous designs had featured two bottles spaced vertically (“Tandem Blow”) but the machine featured (but not running) at NPE2009 showed a mold with two bottles spaced horizontally. This “Multi-Parting Line” is similar to what injection molders know as a stack mold. It uses the same machine frame and controls, with a special head and blow pin station. The machine on display was set up to mold a 30-gram bottle in 16 cavities at a rate of 5,250 bottles per hour.
Sacmi of Italy showed a new compression molding machine for containers that molds a preform, then blows a container similar in principle to the injection blow molding process. The CBF range of machines excels in lower power consumption, and quick color changes, and is geared towards the market for smaller pharmaceutical containers. Outputs of up to 21,000 bottles per hour are said to be achievable.
Another machine shown running was an 88-ton IBM machine at the booth of PET All Manufacturing Inc. The model, 300/700 with inverted head, was molding a 30-ml, six-gram bottle running with 16 cavities at an output rate of 5,000 bottles per hour.
On the PET stretch blow molding side, SIPA of Italy showed three machines with two, six, and 12 cavities respectively. The exhibited SFL 2 machine was molding two four-gallon containers at an output rate of 1,100 containers per hour. The same machine can also produce a 40-litre container in a single cavity. The displayed rotary SFR 12 EVO heat-set machine uses molds that are electrically heated rather than with high viscosity oil. This allows an easy switch between hot-fill and standard applications, a “hot” topic for many companies that need this flexibility to adjust to seasonal demand fluctuations.
Canadian moldmaker Wentworth also showed improvements in heat-set molds. The Wentworth mold shells are thermally isolated from the carrier, resulting in energy savings, and reduced temperatures in the blow machine.
When it comes to linear stretch blow machines, all-electric (i.e., non-hydraulic) machines are becoming more and more popular. As in injection molding, solving the large clamp tonnage requirements is key. Canadian machinery producer Amsler Equipment showed single and dual-cavity machines that can blow up to 1,800 bottles per cavity per hour, and feature several servomotors, including the stretch rods. CPL