Technology Showcase (January 01, 2005)

INJECTION MOLDING

Modular tiebarless machines extended to larger sizes

Engel’s Victory line of tiebarless injection molding machines has been extended up to 240 tons, and will include models up to 330 tons in the spring. The new sizes currently available are 200, 220 and 240 tons. Injection capacities range from 3.7 oz. to 44 oz.

The Victory line uses the concept of platform-based modularization which leads to shorter delivery times, an improved price-performance ratio and simpler upgrade capability. For greater flexibility, the Victory line has been pre-designed in over 200 two-component configurations.

Engel 519-836-0220

Larger hybrid IMMs suitable for stack molds

In response to feedback from North American molders, Demag Plastics Group is expanding its EL-EXIS line with the addition of 615-ton and 780-ton models. The EL-EXIS line is suitable for an array of packaging and closure applications for food and beverage, technical and medical industries.

The EL-EXIS combines the repeatability of all-electric machines with the fast-cycling action of hydraulic designs by incorporating a hydrostatic drive.

The new 615-ton model has generous platen dimensions and wide tiebar distances. A linear bearing guidance system supports the moving platen, and ensures easy and smooth closing and opening movements. The injection units provide high injection pressure and long injection strokes to handle large shot weights and to overcome the long flow distances in stack molds.

Stephen Sales Group 905-940-5577

CO2 cools mold hot spots

A particularly effective cooling method for injection molds – CO2 spot cooling — has been developed by Linde and ISK of Germany. CO2 spot cooling can efficiently cool the hot spots within a mold, such as very thin portions, small cores or local material accumulations.

This method uses highly pressurized liquid carbon dioxide that flows through thin, flexible capillary tubes (1.6 mm OD or less) to the spot to be cooled. When expanding, the CO2 produces a snow-and-gas mixture at about -79C with a high cooling capacity. The CO2 removes heat from the tool steel and leaves the mold as a gas through appropriate outlets.

CO2 spot cooling is not meant to replace water cooling, but to complement it.

Linde Gas LLC 216-642-6600

BLOWN FILM

Grooved rollers simplify film granulator

The feed rollers on the new film-trim feed system for Conair’s CHS Series granulators are designed with a grooved surface that eliminates the need for the dancer mechanism and electronic speed controls that usually complicate such systems. The rollers themselves never actually touch, so wear is reduced, but the efficient feeding of trim scrap or scrap film rolls is not affected.

These trim systems can handle material at rates up to 300 ft. per minute.

In contrast to conventional knurled rollers, the Conair drive and pressure rollers have circumferential grooves that intermesh such that the peaks on one roller fit into the trough of the other roller.

If the extrusion line slows and the film feed rate is slower than the speed of the granulator feed rolls, the film will actually slip between the rollers rather than breaking or pulling. This eliminates the need for a more conventional dancer bar and electronic loop control that are usually required to slave the feed roller speed to extruder output.

Stephen Sales Group 905-940-5577; Auxiplast Inc. 450-922-0282

Film thickness sensor maintains constant measuring distance

The VenPad capacitive thickness profile measuring system permits non-contact measurement on the outside of the film bubble. In contrast with other non-contact sensors, the VenPad sensor maintains a constant and extremely small distance between itself and the film bubble, ensuring exact and reproducible measuring conditions.

The VenPad system is designed so that air flows at high speed tangentially between the film and sensor, creating a venturi effect, which generates an air cushion of constant thickness. So the system operates “automatically”, without any need for adjustment, at a constant distance from the surface of the film.

VenPad is equipped with a Profibus interface for use with existing extruder control systems, or it can be used in conjunction with Octagon’s SmartLip thickness profile control.

Octagon Process Technology 49 931 2796 70

EXTRUSION

Dustless cutter for extruded shapes

The CFPC Series planetary cutter from CDS is designed to cut tubular extrudates with minimal dust and debris. The cutting assembly travels with the product while the blade makes its incision. It is capable of up to 60 cuts/min., which equates to line speed of approximately 20 ft./min.

The CFPC planetary cutter can also be equipped with a dead stop assembly for greater cutting precision.

Tubes or shapes with 2-1/2 to 8 in. O.D. can be cut, with wall thickness up to 3/16 in.

CDS 877-633-1993

Foam sheet and profiles benefit from twin-screw technology

Berstorff has introduced a new concept for lower throughput foam production lines: a twin screw, co-rotating extruder with a downstream melt cooler. The new machine is suitable for polyethylene foam tubes and profiles; expanded polypropylene, polyethylene and polystyrene sheet; and expanded polypropylene beads.

The combination of twin screw extruder and melt cooler takes advantage of the excellent mixing capability and the economic efficiency of twin screw extruders. It allows a higher proportion of reclaimed material to be used, and allows CO2 to be used as the blowing agent.

The melt cooler acts as a static cooler, and cools the melt by 30C to 50C to obtain the ideal temperature for foaming.

Berstorff 859-283-0200

AUXILIARIES

Hybrid laser welding suitable for large 3-D parts

Laserquipment has developed a hybrid polymer welding technology which combines the cost-effectiveness of conventional light welding systems with the efficiency of laser welding technology. The dual method of irradiating the weld seam provides new possibilities for design and contributes to increased process stability.

The evenly-distributed temperature field in the welding plane leads to shorter cycle times with less required laser power, compared with conventional laser contour welding.

This hybrid process also extends the range of welding applications onto large, three-dimensional parts that are currently unable to be welded with established laser welding methods.

Laserquipment 503-454-4200

Precision screw-less feeding of additives

To accurately dose free-flowing additives or masterbatch, Colormax offers the Posimax B200 and B300 feeders, which use a patented screw-less feeding mechanism. The Posimax units use a feeding disc to create a phenomena known as positive displacement feeding.

The feeding disc is the only moving part on the Posimax feeders, and has led to these models being known for exceptional accuracy, low maintenance and ease of use.

For injection molding, Posimax provides superior linear accuracy, achieving consistent color accuracy when molding parts. The Posimax feeders can also be used for extrusion, volumetric blending and gravimetric blending.

Colormax 856-256-3045

Probe monitors color in the melt stream

Facts has equipped its Equispec Color Analyzer system with a durable melt probe which monitors color directly in the melt stream. This new probe extends the versatility of the Equispec system, which is designed to monitor, control and log color during the extrusion of plastic products.

The fibre-optic probe has seven illumination fibres and a sapphire-tipped window which allows light to emerge from the probe and strike the melt material. The diffusely scattered light is then picked up by the probe and returned to the instrument for analysis.

With the in-line process monitoring capability of the Equispec Color Analyzer, the processor obtains real-time color drift information, and can make corrections without stopping the web.

Control Solutions Inc. 905-458-8382

MATERIALS

Resin purification a
vailable for small lots

A unique resin purification service that significantly reduces the level of ionic impurities in polymers is now offered by PolyClean Technologies. “The cleanliness and purity requirements for polymers in critical applications continue to become more demanding. This is a challenge for resin suppliers who must find economical ways to reduce the level of residues in their virgin polymers and compounds,” explains Harish Sangani, president of PolyClean.

Sangani also notes that it may be difficult for molders to find suppliers willing to meet stringent cleanliness requirements for small, niche applications.

The purification process can be performed on virgin pellets, materials that may have been contaminated by process upsets or improper handling, or on regrind.

PolyClean Technologies Inc. 832-595-9660

Cyclic form of PBT becomes commercial

The Cyclics Corporation announced its first commercial product grades, CBT 100 resin and CBT 200 resin, will be available early in 2005 from their plant in Schwarzheide, Germany. Both resins melt to a water-like viscosity when heated then polymerize into the engineering thermoplastic polybutylene terephthalate (PBT) when catalyzed.

CBT 100 resin has a processing temperature between 190-240C and will be available in both one and two-part systems. This resin is formulated for compounding, injection molding, nanocomposites, rotational molding and as a carrier resin for color and filler concentrates.

For applications requiring a lower processing temperature, CBT 200 resin has a processing range between 170-240C and is formulated for various casting, low pressure molding, coatings and composite applications.

Cyclics Corp. 518-881-1411

Blending control can also function as conveying control

Gravinet is a new blending control for Motan’s Gravicolor gravimetric batch blenders. It can control, manage and monitor a Gravicolor unit with up to six material components. An optional integrated convey control can manage up to seven material loaders and one blower for the conveying system. The loaders can be used to feed other production equipment as well as the Gravicolor blender. Thus, for smaller applications, Gravinet eliminates the need for a separate conveying control.

An embedded micro-controller and an on-board Ethernet port facilitate communication with other Motan blending, conveying and drying units. Self-optimizing process control ensures high blending accuracy with automatic material calibration. The Gravinet also has efficient vibration control for fast-cycling injection molding machines.

Motan Inc. 800-991-9921

Engineering thermoplastic fuel cell costs less

Ticona has introduced a fuel cell prototype made of engineering thermoplastics, which could reduce the fuel cell cost by at least 50% compared with fuel cells fabricated of other materials. The 17-cell unit contains injection molded bipolar plates of Vectra liquid crystal polymer (LCP) and end plates of Fortron polyphenylene sulfide (PPS).

The Ticona prototype is a proton exchange membrane (PEM) fuel cell.

The Vectra bipolar plates, which contain 855 powdered carbon, are molded by SGL Carbon. With a cycle time of only 30 seconds, they can be produced in volume without the labor- and cost-intensive machining and finishing that other materials may require.

“The LCP’s ability to carry a carbon loading of over 85% and still process well goes beyond what nearly any other plastic can do,” says Frank Reil, manager, market development for Ticona. “In addition, both polymers have excellent long-term performance because they withstand the aggressive media found in fuel cells and remain dimensionally stable, even at temperatures as high as 200C.”

Ticona 800-833-4882