US 12,304,125 B2Granted

Plasticizing unit

AssigneeKraussMaffei Technologies GmbH

InventorsStefan Schierl, Andreas Bierbaumer, Thomas Drogi, Martin Würtele, Lazlo Giesgen

Life of this patent

Estimating the term…

Loading patent…

Abstract

The application relates to a plasticizing unit with a cylinder and a screw that is rotatably mounted in the cylinder and has a screw section which is designed as a shearing section and in which a blocking web encircling the screw core in a helical manner and a main screw thread enclosed by the blocking web are provided. A shearing web runs in the main screw thread parallel to the blocking web at a lower height than the blocking web. In this manner, two screw threads are produced which run parallel to each other and are separated by the shearing web. The threads are designed in the form of wave screw threads. Each wave screw thread is equipped with one or more wave peaks with a surface which is designed in the form of a plateau and forms a wave peak shearing surface, wherein the wave peak shearing surface is located at the same height as the surface of the shearing web in the region. The shearing web surface section which lies in the region of a wave peak shearing surface constitutes a shearing web sharing surface. A wave peak shearing surface and a shearing web shearing surface together form a total shearing surface. A specified total shearing surface together with the inner wall of the cylinder forms a shearing gap in accordance with a shearing gap size specified for the total shearing surface.

A plasticizing unit (1) for an injection moulding machine or an extrusion system, wherein the plasticizing unit (1) comprises:

a cylinder (2) and a screw (3) arranged rotatably therein,
wherein the screw (3) has a screw section formed as a shearing section (B),
wherein in the shearing section (B) the screw (3) has a blocking web (4) encircling the screw in a helical manner, and
a main screw thread (5) enclosed by the blocking web (4),
wherein in the main screw thread (5) a shearing web (6) is arranged parallel to the blocking web (4),
wherein the shearing web (6) has at least a part with a smaller height than a height of the blocking web (4) and at this part a surface (6a) of the shearing web (6) forms a shearing web shearing surface (SFS),
wherein in the main screw thread (5) a first wave screw thread (7) and a second wave screw thread (8) are provided, each running parallel and spaced apart from one another by the shearing web (6),
wherein the first wave screw thread (7) has a first thread base (15), running in a wave-shaped manner in a conveying direction of a melt, and the second wave screw thread (8) has a second thread base (16) running in a wave-shaped manner in the conveying direction of the melt,
wherein wave peaks (9) of the first wave screw thread (7), when viewed in the conveying direction of the melt, lie offset with respect to wave peaks (10) of the second wave screw thread (8),
wherein the wave peaks (9) of the first wave screw thread (7) and the wave peaks (10) of the second wave screw thread (8) are each provided with a surface (9c, 10c) configured as a plateau forming a wave peak shearing surface (SFW),
wherein a length (LW) of the wave peak shearing surface (SFW), when viewed in the conveying direction of the melt, is longer than a width (B4) of the blocking web (4), and/or a width (B6) of the shearing web (6) is wider than the width (B4) of the blocking web (4) at the shearing web shearing surface (SFS),
wherein the wave peak shearing surface (SFW) is situated at a same height as a height of the surface (6a) of the shearing web (6),
wherein the wave peak shearing surface (SFW) and the shearing web shearing surface (SFS) together form an overall shearing surface (SFn),
wherein the overall shearing surface (SFn) forms with an inner wall of the cylinder (2) a shearing surface shearing gap (SZ1), and
wherein in both the first wave screw thread (7) and the second wave screw thread (8) more than one overall shearing surface (SFn) is present, and a size of the shearing surface shearing gap (SZ1) becomes smaller in the conveying direction of the melt.

12 more elements

Abstract

Claims15