Heating cylinder device for a molding machine

Abstract

This heating cylinder device for a molding machine includes a cylinder member along the axial direction of which and within which are defined several heating zones for material to be molded, each of the heating zones being provided with a heater, wherein the heating capacities and the thermal conductivities to the exterior of the heating zones are suitably arranged so as to correspond to the temperatures and operational performances required from the heating zones. Each of the heaters may optionally surround the portion of the cylinder member defining its heating zone. The external diameter of the portion of the cylinder member defining each of the heating zones may be varied according to the heat capacity and temperature required therefrom; or, the portions of the cylinder member between its portions defining the heating zones may be substantially narrowed down as compared to its portions defining the heating zones; or, each of the heaters may be buried in the portion of the cylinder member defining its heating zone; or, a plurality of layers of insulating material may be provided as surrounding a plurality of the heating zones and the heaters surrounding them. In the last case, these layers may be of different thicknesses.