New multi-material rotary stack-mold system. (Keeping up with Injection Molding).

A new rotary stack-mold technology for high-volume production of multi-component parts has been developed by MGS Mfg. Group of Germantown, Wis. MGS is said to be one of the world's largest multi-component injection molders and moldmakers. It also markets the Universal Multishot System (UMS), a line of specialized equipment components for multi-shot molding.

The new rotary stack mold has a center mold section with two or four faces that turns on a vertical axis. Four faces allow for added cooling or insert functions. The table is indexed with an AC servo motor and has its own stand-alone control that uses the SPI-interface signal from the injection press (similar to a robot). This system may make it economical to convert assembled parts such as caps, closures, or disposable devices into multi-component molded products.

Although this horizontal rotary platen can be used on any horizontal press, a joint development with Krauss-Maffei Corp., Florence, Ky., has resulted in a new "Revolution" series of machines for high-volume, multi-component applications. Based on K-M's C and MC series of two-platen presses, Revolution machines come in 200, 400, and 600 tons, as well as sizes above 2000 tons. Revolution models have a second injection unit mounted horizontally behind the moving platen, which injects through the center of that platen. (It makes the machine narrower than a traditional "L" configuration.) The ejector system has been moved to the center rotating mold section.

Modified for high speed, the machine has nozzle shutoff valves on both injectors, an electric-driven screw, and a hydraulic accumulator to speed injection (24 in./sec) and clamp build-up. The first Revolution machine, a 200-ten model, has been installed at MGS. The press will appear in K-M's booth at NPE in June, where it will mold a polycarbonate cell-phone battery cover with a TPE seal. MGS [phone], www.mgstech.com; KraussMaffei [phone], www.krauss-maffei.com