摘要 |
An induction furnace utilizes a channel-shaped induction coil disposed along a mandrel movement line within a cup-making machine to produce eddy currents within a conductive grid arranged intermediate between the induction coil and the mandrel movement line and also within the mandrels themselves. Cylindrical thermoplastic sheet blanks are mounted on the mandrels, and as a result of the heat generated by the eddy currents within the conductive grid and mandrel itself, shrink about the mandrel to produce a finished container conforming to the surfaces of the mandrel. The induction coil is driven by a high frequency alternating current power supply and may be controlled by the placement of a thermocouple within the furnace. By varying the permeability of the inductive grid and the forming mandrel, the mandrel temperature may be controlled separately from the temperature applied to the exterior surface of the cylindrical blanks of thermoplastic material by the conductive grid.
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