Plastification- and injection device for microinjection molding, comprises plastification cylinder and a rotary-propellable snail with volutions

The plastification- and injection device for microinjection molding, comprises plastification cylinder (5) and a snail with volutions. The snail is formed conically thrust snail in conveying direction. The snail is coupled with rotatory drive (4) and linear drive. A piston-spraying device is connected with the plastification cylinder via a melt channel (11). Displacement means are intended for the adjustment of the width DELTA of the gap between the snail outside diameter and the cylinder inside diameter. The plastification- and injection device for microinjection molding, comprises plastification cylinder (5) and a snail with volutions. The snail is formed conically thrust snail in conveying direction. The snail is coupled with rotatory drive (4) and linear drive. A piston-spraying device is connected with the plastification cylinder via a melt channel (11). Displacement means are intended for the adjustment of the width DELTA of the gap between the snail outside diameter and the cylinder inside diameter. On the melt way of the conical snail to the piston-spraying device an intermediate storage is intended for the reception of plastic melt, so that the snail can be continuously operated. A gravimetric metering unit is intended in the device. A section continuously decreases in conveying direction of the outside diameter of snail webs (3) and the diameter of snail core (2) remains constant. An independent claim is included for a method for the production of lesser weft weight for microinjection molding. Beschrieben wird eine Plastifizier- und Einspritzvorrichtung für das Mikrospritzgießen mit einem Plastifizierzylinder (5) und einer darin angeordneten und drehantreibbaren Schnecke (1) mit einem oder mehreren Schneckengängen (16) sowie mit einer Kolbespritzvorrichtung (13, 14, 15), die über einen Schmelzekanal (11) mit dem Plastifizierzylinder (5) verbunden ist. Die Erfindung zeichnet sich dadurch aus, dass die Schnecke (1) in Förderrichtung konisch ausgebildet ist und dass Verschiebemittel (8) zur Einstellung der Weite DELTA des Spaltes (9) zwischen dem Schneckenaußendurchmesser und dem Zylinderinnendurchmesser vorgesehen sind. Auf diese Weise kann das Spiel zwischen dem Schneckenaußendurchmesser und dem Zylinderinnendurchmesser in geeigneter Weise eingestellt werden, um insbesondere scherempfindliche Materialien mit dem "richtigen" Spalt verarbeiten zu können.