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Blown film line created for Research and development

The Microblown film line was shown for the first time at Antec 2002 in San Francisco. Its entire mechanical assembly has a footprint of just 30 by 30 inches, and the complete line (with the control panels stacked vertically) adds another 12 inches to the length.

The film line is designed for research, development, and quality control applications. It makes film from about 1 to 18 inches wide. The line reportedly allows the user to test and improve resins, additives, and colorants, and can be used to test for elongation, impact, shine, transparency, and gels. In quality control applications, a user can test viscosity (with the online rheometer), gels, melt strength, pressure, and contamination. Secondary testing of film strength is also possible.

The line uses vertical compounding screw extruders ranging from .25 to 1.25 inches in diameter. To withstand the stress of feeding, melting, mixing, and pumping the screws are driven through the metering section. The metering section?s root diameter is reportedly about 2.4 times as strong as the weak feed-section root diameter.

Randcastle Extrusion Systems
Cedar Grove, NJ
(973) 239-1150

Optical micrometer for small targets

The LS-7010 CCD optical micrometer measures targets as small as .04 mm with an accuracy of ±.5 µm and a repeatability of ±.06 µm. Reportedly half the size of other optical micrometers, the compact LS-7010?s measuring head is only 9 inches long. The measuring range is .04 to 6 mm.

The LS-7010 is designed for use with specialized, precision applications such as catheters and a broad range of small parts and components. One model includes a complementary metal oxide semiconductor (CMOS) camera in the receiver head, which images the target area on the target-viewer monitor. The monitor enables users to quickly and accurately position the target in the beam for more precision.

Unlike some laser scanning micro-meter systems, the LS-7010 measuring head uses no motor or rotating-prism mechanism. A high-intensity LED light source and an HL-CCD (high-speed, linear CCD) offer speed and accuracy. The sampling rate of 2400 samples/sec is reportedly two times that of conventional laser scan micrometer systems. With no moving parts, the LS-7010 measuring head generates no heat or vibration.

Keyence Corp. of America
Woodcliff Lake, NJ;
(888) 539-3623

Servo robots have fast takeout times for short mold cycles

The AZ-100HP three-axis high-performance top-entry servo robots reportedly feature fast takeout times. Molders with applications that have cycles of less than 4 seconds?and who are looking to achieve sub-.5-second takeout times?are said to be good candidates for this robot. The series comes standard with an AAC color graphical user interface that features simple touch-screen operation.

Automated Assemblies, Clinton, MA
(978) 368-8914;

Oil-free tiebarless IMMs

The E-Motion series of tiebarless, four-motor, servomolding machines is available in 60-, 110-, and 165-ton models with either 130- or 250-mm/sec injection. All E-Motions feature a horizontal C-frame toggle-clamp design, which includes a Flexlink feature for offsetting deformation under load. The high-resolution, absolute-position encoder was patterned after those found in machine tools.

The machine is available with a linear Engel robot for high-precision insert molding. Also available is the CC 200 touch-screen controller.

Engel, Guelph, ON
(519) 836-0220

Sprue picker features upgraded control for efficient setup

A new line of high-speed sprue pickers is designed for injection molding machines with clamping forces from 25 to 500 tons. Equipped with an upgraded control for fast and efficient programming, HOP III-M Series three-axis robots are available with main arm strokes of 450 to 1000 mm and can dry cycles in less than 3.5 seconds. New handheld controls offer expanded memory for mold setups, making changeovers quick and easy. The controllers reduce programming time by allowing users to select from dozens of preprogrammed motion patterns, gripping methods, pickup and release positions, and other mechanical functions.

All HOP III-M models include prelubricated, sealed linear bearings for reported long life, smooth operation, and minimal maintenance requirements. The units also include toolless kick-axis adjustment and adjustable main arm starting position, as well as safety features: proximity switches at the endpoint of every motion and a pneumatic arm lock-out device to prevent the arm from dropping into the mold area if air pressure is lost. The entire line has been discounted 15 percent. Five models are available at the reduced cost, with prices ranging from $4030 for the HOP III M450 to $5390 for the HOP III M1000.

Yushin America Inc., Cranston, RI
(401) 463-1800;

Multilayer blown Film Technology

Kirion multilayer blown film lines are arranged on a modular system that can be configured to produce up to seven layers. The three-layer system is arranged for production of standard films as well as technical films with a maximum layflat width of 2200 mm. The outer and inner layers are each fed by a 60-mm extruder, the middle layer by a 100-mm model. Hydraulic screenchangers are used exclusively so that product changes and maintenance are simplified.

Gravimetric feeding of the three-layer line allows feeding of three additional side components per extruder, even in minimum quantities. The gravimetric system can be extended, so dosing of a maximum of six components in addition to the main polymer is possible. The control system ensures recipe compliance and can be set up from the central operating screen.

The three-layer die with computerized spiral mandrels has a diameter of 500 mm. Even melt distribution and low residence time yields high output.

Kirion T hauloff enables different flattening lengths for various profile requirements. The coextrusion line has a module in which a minimum flattening angle of 8.5° (measured against the perpendicular) can be set. This results in advantages for difficult-to-produce technical films, which are susceptible to bagginess and other problems. Both the flattening angle and the central tubular film guide are directly controlled from the control console and hauloff. The collapsing frames are fitted with brushes, which absorb a minimum amount of heat and offer advantages for scratch-sensitive and sticky films. A turning bar system handles very sticky and optically sensitive films.

Kiefel Inc., Wrentham, MA
(508) 384-1200;

Case packer for blowmolded containers has indexing infeed conveyor

An automated carton infeed system works with a packaging system, permitting one operator to service several production lines, reducing labor costs. A variable-speed indexing drive mechanism aligns the carton into the packing position, where an automatic vacuum system draws plastic liners tight against carton walls so neither the product nor the tooling are snagged during packing.

The packaging system can pack containers into a carton with necks up or down, in either offset or alternating rows. A color touch-screen operator interface stores job parameters in memory for instant recall and efficient changeovers. Full cartons are discharged onto a gravity conveyor that can feed a taping machine and/or a palletizer.

Proco Machinery Inc.
Mississauga, ON; (905) 206-9392

Overmolding overview

Editor's note: The following information on overmolding was taken from a report on the subject created by Lonnie Tustison, tooling manager of Tooling Express Inc. (Bellevue, ID).

Just as it can help a product differentiate itself, overmolding or insert molding can help a molding shop stand out in the plastics processing crowd as well. Molding softer materials like TPE over metals or other plastics can enhance the grip and ergonomics of a product as well as make it visually appealing without sacrificing structural strength. Despite the many potential benefits of adopting the process, there are several areas processors should examine before they decide to take on overmolding themselves.

Material compatibility
Virtually any material can be overmolded onto another one, but that doesn't mean they'll stay that way. If chemical reactions occur between the different materials that affect adhesion, one material will eventually begin to peel away from the other. Make sure the materials you're looking to join are indeed compatible.

Consistent insert tolerances
If there are any inconsistencies with the size and shape of the inserts, this will adversely affect the end product. In the case of machined steel or metal inserts, any variation in insert dimensions will affect how it is seated in the mold prior to resin injection. In the case of one thermoplastic being overmolded onto another, inconsistencies in the size and shape of the inner component can also affect the end product. Molds are designed to compensate for material shrinkage, but if the final tolerances for a part are in the area of ±.005 inch, there isn't much room for error. Molders should remember that some materials take several days to cure. In addition to not overmolding these parts until they've reached their final dimensions, care needs to be taken in their handling and storage.

Potential applications
The ability to enhance the ergonomics of a wide variety of products has made the overmolding of soft-grip materials over hard structural materials standard practice in everyday items like toothbrushes and kitchen utensils. Not only is greater functionality added, but product aesthetics are usually increased as well. In terms of product assembly, the insert molding of metal threads can increase the life span of components that require screws for disassembly. Metal threads also provide greater strength and durability.

In truth, any application in which a contrast of colors and/or textures would help draw consumer interest to a product is a likely candidate for insert or overmolding. It's up to molders to examine their business and account for all the different variables.

Quality up, costs down with inline compounding

When Krauss-Maffei (KM) showed the prototype of its IMC (Injection Molding Compounding) system at K 1998 in Germany, IMM heard many people wondering who could possibly use it. At the same time, others—the early adapters—were forming ideas of how to use it. Many of the latter seem to have been from the automotive sector, for at last year's K Show it was clear the IMC system had taken root there. That is no surprise to KM: The molding-compounding combo is targeted at large parts needing reinforcement and/or additives.

At K 2001, a 1000-metric-ton IMC system produced a tailgate of glass-fiber-reinforced ABS that was inmold-decorated with multilayer film. The show system was bought by French auto supplier Faurecia, which has since added two more and ordered a fourth. Another two are working in Germany and one more is at an undisclosed molder in the U.S. IMC systems are now in serial production and can be purchased with KM's full range of clamps: 650 to 5400 metric tons. Each clamp can be paired with up to four injection—or should we say compounding—capacities.

In an IMC system, the reciprocating screw injection unit of a standard injection machine is replaced by a corotating twin-screw extruder and a special injection unit. Between those sits an accumulator that fills during injection and holding to form a buffer between continuous extrusion and intermittent injection. Compounded melt from the extruder is piston-fed from the accumulator to the injection unit. The accumulator and injection unit operate independently, separated by a control valve so that maximum pressure buildup is held during injection. Polymer and additives are gravimetrically metered into the extruder.

An industrial robot is shown removing an automotive tailgate panel (above) that has been inmold decorated using preformed film.
In the IMC System, melt is forced from the extruder into the temperature-controlled melt buffer (A). The injection piston is retracted, permitting material to enter from extruder and buffer. When the shot volume is reached, a valve (B) closes off the buffer. Injection follows, during which the extruder continues feeding material into the buffer. A separate valve (C) shunts extrudate to a tank during startup and shutdown.
Interlocking Advantages
Combining compounding and molding in one system can reduce production costs vs. two separate systems. It also means improved material quality as it is heated only once. Twin-screw compounding allows gentler plasticating of heat-sensitive compounds and a thorough mixing of virtually any conventional filler or reinforcement. KM also reports that reinforcing fibers are thoroughly coated, are evenly distributed in the melt, and can retain significantly more of their length than is possible in normal injection molding.

The twin screws in KM's IMC system are segmented. The segments can be varied to match the processing needs of a particular compound, including powdery or sticky mixes. Apart from customizing the screws, a basic twin-screw system provides a wide processing window and broad flexibility with formulations. Melt quality can be influenced by adjusting screw speed and/or varying the amount of material metered into the extruder. The system allows high shot weights for large parts like pallets or bumpers, or for parts in a stack mold.

The clamp of the IMC is the two-platen design of KM's MC Series injection machines and allows for large molds and stacks. A valve has been provided that opens during startup or during a fault to divert material from the extruder into a tank to prevent it from being injected. The system is designed so that no material remains in the buffer chamber from shot to shot. Similarly, the full volume is purged from the injection unit with each shot to avoid residue. A control valve between the melt buffer and injection unit allows them to operate independently to provide maximum injection pressure on each cycle.

The melt buffer enabling the crossover from continuous extrusion to intermittent injection is the tallest part above the injection unit it helps fill.
The IMC system uses KM's MC4 injection control and its C4 extruder control. The operator panels are side by side for an easy view of the whole process, and the similarity of the interfaces is evident. The hardware components are identical, and the controls are linked on the software level so that operation of the two-part system is unified for the operator.

Besides applications development in areas such as automotive, furniture, and material handling, KM is working to broaden material options. Its engineers are collaborating with the Institute of Plastics Technology at the University of Stuttgart to advance the use of natural fiber in these molded composites. Results have been positive with flax/PP combinations, including the odor problem previously associated with intense heating of these fibers. Further research and development using hemp, jute, and other natural fibers in a variety of thermoplastic materials are ongoing.

Contact information
Krauss-Maffei Corp.
Florence, KY; (859) 283-0200

Two-shot modular molding

Kunststoffwerk Kutterer GmbH & Co. KG (Karlsruhe, Germany) wanted to increase the output on a two-component shampoo bottle cap program it was running but didn't have the capacity or desire to buy a second multicomponent press to team with its existing two-component machine. The molder produces about 2.7 billion caps every year for OEMs in the pharmaceutical and cosmetic markets like L'Oreal, Unilever, and Wella. For this particular program, a 3500-metric-ton machine was molding 4.7g shampoo caps with a .2g strip of coloring for added style. The parts were created in a 24-cavity hot runner mold that used core pulls and cycled parts in 13.5 seconds (see photo, top). Enter Windsor Kunststofftechnologie. Part of the Cannon Group, Windsor offered the option of its PlugXPress modular injection unit, which can be retrofitted to any standard injection molding machine to make that machine a multicomponent press. Kutterer decided to add the WKT1 PlugXPress to an existing 3500-metric-ton press and used its 24-mm-diameter screw to plasticate a maximum shot weight of 46g (see photo, below).
With only eight weeks to get the program running, a new multicomponent press was not an option because of the time needed for delivery and setup. Windsor delivered thanks to the modular design of the PlugXPress, which can be integrated quickly and situated at any angle to the press. This allows for the addition of other PlugXPress units, making two, three, or even four-component injection molding possible. Kutterer says the Windsor unit produced caps identical to the multicomponent machine in terms of quality and performance.

Contact information
Windsor Kunststofftechnologie
Hanau, Germany; +49 (6181) 9003-0