Medium-Pressure Machine for Structural Foam
Wilmington’s 500-ton model is suited to both solid molding and thin-wall structural foam.
Wilmington Machinery has launched the Lumina MP500 medium-pressure injection machine, a 500-ton version of the MP800 introduced several years ago (Feb. ’17, Keeping Up). Though capable of solid molding, the MP500 is aimed primarily at structural foam parts for automotive, recreational, material-handling and enclosure parts. Compared with Wilmington’s low-pressure foam presses, the MP500 has twice the injection pressure and clamping force, suitable for molding thin-wall or core-back foamed parts. But in common with the firm’s low-pressure machines, the MP500 has a 30:1 L/D plasticating unit capable of compounding additives and processing 100% recycled materials, as well as being ported for direct gas injection.
Like the MP800, the new, smaller model has a reciprocating screw as standard with two-stage (screw/plunger) injection optional. The reciprocating-screw version comes with a reportedly unique inline accumulator that offers double the shot volume typical for a given screw diameter while retaining first-in/first-out performance. Shot size for foam is 40 in.3 (approx. 15 lb of HDPE); for solid molding it’s 240 in.3 (approx. 7.5 lb HDPE).
The two-platen clamp has tiebar clearance of 42 × 42 in. and usable mold space of 60 × 42 in. Hydraulic ejection is standard.
It may seem like a dull topic, but it will overcome the emotional experience that follows when you put a new mold into a machine and you find out there is not enough barrel capacity to make a full shot.
What it means. Why it's important.
One of the important process parameters to establish and record for any injection molded part is its injection or fill time. Research research reveals the limitations of popularly taught methods of establishing this critical parameter.