Injection unit screw and injection unit

Abstract

To provide a screw of an injection device with two stages that can facilitate injection of foaming gas.SOLUTION: A screw 20 of an injection device 1 has a first stage 30 provided at the upstream side U and a second stage 40 provided downstream from the first stage. In the second stage 40, a resin pressure suppression area 40A is provided on the upstream side U of it, the resin pressure suppression area 40A having one or more flights, where the groove depth D40A is deeper at the downstream side L than at the upstream side U. Preferably, the first stage 30 has a compression section 30B provided with a main flight 33 and a sub-flight 35 with a smaller outer diameter than the main flight 33. The second stage 40 is provided with a plurality of fin groups 45 comprising a plurality of plate-shaped fins 44 spaced in the circumferential direction and spaced in the direction of the central axis C, on the downstream side L from the resin pressure suppression area 40A.SELECTED DRAWING: Figure 1

Images