Injection moulding plastic with more than two ingredients - using central passage surrounded by annular sleeve having 2nd annular passage with axially slidable shut-off body

摘要

Plastic is injected by a head with central passage, round which is an annular one shut off by a sliding sleeve. Inside the sleeve is a second annular passage, shut off by a needle body sliding in the axial direction. The central passage is formed by a bore in this body. The core can contain a one-way valve, situated between two coaxial sections of the body.