Europeans testing Ultramelt process
Four European plastics trade associations have spearheaded research into using ultrasonic vibration welding to improve polymer flow during injection molding and extrusion by lowering melt viscosity. They call the process Ultramelt.
The groups are Assocomaplast in Assago, Italy; Valencia, Spain's AVEP polymer processors association; the Danish Plastics Federation in Copenhagen; and the Polymer Machinery Manufacturers & Distributors Association Ltd. of Rugby, England. Several European firms, as sponsors and research partners, also are supporting the work.
In extrusion, in-line rheological measurements showed that Ultramelt decreases the melt viscosity of plastic by 40-60 percent, depending on the material, with no loss of mechanical properties. The lower viscosity is a short-term effect, however, and the rheological properties and viscosity recover with time to original levels.
During injection molding trials, a platen-mounted prototype was tried. Ultramelt can double flow length during injection of certain materials - using the same injection speed and pressure. The drop in viscosity means injection speed increases and pressure requirements during filling decrease.
Using the same shot size and processing conditions, the injection time of a polypropylene part was cut by 45 percent. The highest increases in flow have been measured at 3.0 with a low melt-flow index grade of PP.
How does it work? According to the trade groups, Ultramelt appears to reduce the degree of entanglement in polymer chains.
Contact PMMDA in Rugby at tel. + 44 (870) 241-1474, fax +44 (870) 241-1475 or e-mail [email protected] pmmda.org.uk.
Arburg GmbH unveils touch-screen control
Arburg GmbH + Co. KG took the wraps off its Selogica injection press controller at K 2004, with a ``direct'' device - Arburg's first-ever touch-screen controller.
At K, Arburg showed the 15-inch touch screen on its Alldrive presses, which use hydraulic and electric drives. But the Selogica direct control now can be ordered as an option on all Arburg machines, according to Christoph Schumacher, marketing manager for the Lossburg, Germany, firm.
Arburg wanted to make the touch screen easy to use through direct access. The new interface also uses far more graphics than the earlier one, which was more text-based. But since symbols from the traditional Selogica have been transferred to the direct version, the keypad is not radically different from the old one.
Also, the navigation structure is always visible as a path in the navigation bar above the screen. The controller clearly separates navigation fields from parameter pages by its screen layout.
Another new feature: direct access fields that are pre-assigned with the most important parameter pages, which change automatically to adapt to the working situation.
Also at K, Arburg:
* Showed new black tie bars, the result of the new Arnox nitriding process to improve corrosion resistance and the sliding characteristics of the bars. Arnox (Arburg No Oxidation) refers to a new plasma nitriding line Arburg installed in Lossburg. The tie bars are plasma-hardened in vacuum ovens as before, then gas-nitrided. Finally, the parts are sprayed with steam to give even more protection against corrosion.
Arburg claims Arnox achieves better results than chromium plating and chemical nickel plating.
* Debuted the Allrounder 270 U. The U stands for ``universal.'' All U machines are equipped with a compact mold clamp with a central drive unit, which provides symmetrical forces in the mold-clamping unit. An optional pivoting clamping unit can move to four different working positions - at K, Arburg molded a Connector insert on a press fitted with injection and clamping units that were both arranged in the horizontal position.
* Premiered the 320 A model of its Alldrive machines. On the A series, customers can choose electric or hydraulic drives - or fully electric - for machine functions. The 320 refers to the 320-millimeter spacing between the tie bars. It comes in clamping forces of 55-66 tons and a range of injection units and screws.
The complete Alldrive series ranges from 55-220 tons.
Arburg's U.S. unit, Arburg Inc., is in Newington, Conn.
Tel. (860) 667-6500, fax (860) 667-6522, e-mail [email protected]
Dukane Corp. offers latest welder series
Dukane Corp. has introduced two new welders: VWA vibration welders, which have a computer-based, color touch screen; and ServoWeld spin welders for assembling thermoplastic parts with circular joints.
The VWA-series welders are mounted on a flexible pendant arm for easy operation. The screen shows many graphs updating parameter information during the weld cycle.
A large x and y graph plots the relationship between the main parameters in real time.
Using an Ethernet connection, data can be stored and retrieved from any network device, according to the company.
With the ServoWeld spin welders, the servomotor controls the radial orientation of the finished part with a high level of accuracy for precise assembly.
Servomotors also produce more torque in a smaller bench-top package, and have a quicker spin-down time, than do machines with induction motors, the company said.
The fast spin-down time eliminates excess flash and bond shearing.
Dukane of St. Charles, Ill., also said it has nearly doubled the stroke on its redesigned ultrasonic thruster and press for plastic assembly.
Tel. (630) 797-4900, fax (630) 797-4949, e-mail [email protected] corp.com.
MIR injection presses using Atomic network
All MIR SpA injection molding machines are going Atomic - the name of the firm's distributed electronic intelligence - and come with the Atomic field CAN-bus: the latest generation of a field bus, or computerized network, with computerized area network architecture.
That means a central processing unit now controls the Italian-made press and all auxiliary equipment.
The CPU is fully integrated within the operator console and can be expanded easily.
Another feature: Atomic machines are self-diagnostic and can sound an alarm - or shut the machine down - if there's a problem.
A single computer can monitor all Atomic machines, regardless of their location.
Also, MIR has rolled out a new touch-screen controller for all its machines.
MIR is based in Brescia, Italy. MIR USA Corp. is in Leominster, Mass.
Tel. (978) 537-4792, fax (978) 840-8213.