Machine Design

From mini to maxi

Megasized two-platen presses may let U.S.based injection molders compete against lowcost Asian competitors.

The large metric Maxima IMMs sport twin injection units, each with 24:1 length/diameter screw, 854-oz shot capacity enabling processing of up to 3000 lb/hr of PE, and 24-kpsi pressure. Software in the machine is preconfigured for coinjection molding.

Maxima IMMs feature extended-clamp opening stroke and daylight for large molds and stack-mold applications. Centrally actuated tonnage is built directly behind the mold, not at the four tie rods, for better part quality and mold life.

Maxima two-platen presses bring fast cycling to coinjection, monosandwich, and sequential two-shot molding. They handle behemoth, 769-oz shots as easily as those weighing a few grams if outfitted with special microinjector units.

The colossal injection-molding machines (IMMs) provide up to 4,000 tons (3,900 metric tons) of clamp force and incorporate dual-injection units that inject through a Y-manifold and a single nozzle. This lets them shoot a large single shot with the combined injector units or cycle rapidly with each unit firing in succession. The IMMs support all multicomponent technologies including core-back, turning core plate, turntable, turning stack molds, and robot transfer. They are equipped for aireject, four-stage hydraulic core pull, and hydraulic mold gating.

Additionally, the IMMs sport centrally actuated, single "pancake" cylinders that build clamp tonnage directly behind the mold using high-pressure hydraulic oil. This reportedly reduces part warpage compared to conventional twoplaten machines where tonnage builds through four tie-rod cylinders at the platen corners — a configuration that can make molds bow under large clamping forces. Center-built tonnages give direct and even clamp force thereby reducing mold wear and boosting part quality and productivity.

The IMMs are coengineered by Cincinnati Milacron, Batavia, Ohio, and Ferromatik Milacron Europe, Malterdingen, Germany, for regional sales around the world. Global designs let molders replicate processes worldwide.

Top-of-the-range Maxima IMMs deliver cycle times with 30-ips clamp speeds and 0.98-sec tonnage build. They have 134-in. (3,403-mm) clamp strokes and maximum daylight of 165.3 in. (4,200 mm) — 195.1 in. (4,956 mm) without an ejector system.

The large daylight capability accepts turning cube (spin-stack) molding applications that can produce over 3,000 multicomponent parts hourly. Such fast throughput may help molders in technologically advanced countries "level the playing field" with low-cost Asian competitors, reports Milacron. Standard machines can also mold deep draw parts with the ejector box removed.

Cincinnati Milacron
(513) 487-5000

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