Big shots in structural foam get even bigger.

Structural-foam molders are used to dealing with large shot sizes, but two processors recently acquired machines with truly gargantuan injection capacity. One of them, Vision Molded Plastics of Napoleon, Ohio, runs the biggest capacity machine ever built by Johnson Controls Inc. of Manchester, Mich. The other molder, Buckhorn Inc., Milford, Ohio, recently became the first molder to install Johnson Controls' newly designed high-capacity machine.

CUSTOM FOAM MOLDING

Vision's largest Uniloy Springfield press from Johnson Controls has some impressive specifications: This 800-ton-clamp monster can process up to 6000 lb/hr and handle shot sizes up to 300 lb. Its platens measure 11 x 15 ft, enough room for the largest structural-foam tools. "It's the only one in the world and the largest machine Johnson Controls makes," says Ron Ernsberger, Vision's general manager. Thus far, the largest shot size Vision has actually run is 154 lb.

Vision also operates six other structural-foam machines - a 150-ton press, four 400-ton models, and a 750-tonner. Vision equipped its machines with capabilities for two-component molding and the low-pressure "Structural Web" process - the structural foam equivalent of gas-assist molding. All the machines come from Johnson Controls.

Unlike the majority of structural-foam molders, which are captive operations, Vision makes products for a wide variety of customers. These include the typical structural-foam applications: pallets, bulk containers, shipping containers, lockers, carts, shelving, and in-ground drainage components. Vision has also used its structural-foam capabilities to enter some more unusual markets - for instance, caskets and dog houses. It has also overmolded polyethylene onto a plastic mesh web to create crowd-control gates. And in a recent project, it insert molded 250-lb wooden railroad ties, encapsulating them with 28 lb of black HDPE foam. According to Ernsberger, the encapsulation process will allow use of a cheaper, more plentiful wood for the ties.

A BIGGER, BETTER MACHINE

Buckhorn Inc. is the first recipient of Johnson Controls' new higher-capacity structural-foam machine, the Uniloy Springfield 1000-ton model. "This new system will provide us with the increased capacity we need to compete more aggressively in the large-format market," explains Bill Tonachio, Buckhorn's general manager. That market includes products such as pallets and bulk containers.

The new machine, which has two 6-in. extruders, offers a total output of 3600 lb/hr and shot size up to 300 lb. Because it also sports two melt accumulators, the machine can process two materials or colors. Platen size is 86 x 167 in. and tiebar spacing is 44 x 137 in. The clamp stroke (120 in.) and daylight (180 in.) are the most generous ever provided by Johnson Controls on a machine of this size.

Finally, the system comes with Johnson Control's Sequential Web Gas Assist Molding Control System, which supports both the Structural Web process and other gas-assist methods.