Injection unit for a molding machine

An injection unit for a molding machine, in particular for an injection-molding machine, with an injection cylinder and a plasticizing screw arranged in the injection cylinder, wherein the plasticizing screw is rotatable about a longitudinal axis in a conveying direction for plasticizing plastic raw material and is movable linearly along the longitudinal axis in the injection direction for injecting molten plastic raw material, wherein, during injection, at the same time as the plasticizing screw moves linearly in the injection direction the plasticizing screw is rotatable in a return direction counter to the conveying direction.

A cylinder front body for retrofitting on a cylinder main body of an injection cylinder, wherein the injection cylinder has a circular-cylindrical inner wall with a diameter which remains constant along the longitudinal axis, wherein the cylinder front body

• has an insertion projection protruding in the direction of the cylinder main body for inserting the cylinder front body into the cylinder main body, wherein the insertion projection has a, preferably circular-cylindrical, outer surface with an outer surface diameter which corresponds at least in regions to the diameter of the circular-cylindrical inner wall of the injection cylinder, wherein the cylinder front body furthermore has
• a circular-cylindrical inner wall with a diameter which remains constant along the longitudinal axis, and
• a nozzle head with a nozzle-shaped inner wall lying in front of the insertion projection and the circular-cylindrical inner wall in the injection direction, wherein the diameter of the circular-cylindrical inner wall of the cylinder front body is smaller than the outer surface diameter of the insertion projection.