| 摘要 |
In a moulding machine comprising means fof feeding melted polymer to be activated or reactivated to create foam with or without an expanding agent to a heated nozzle or die head. The nozzle, die head or a barrel is heated to a first temperature when the machine is at idle (i.e. when no polymer is being fed by the machine/through the nozzle) and is heated to a second temperature higher than the first temperature when the machine is operating (i.e. when polymer is being fed by the machine/through the nozzle). The lower temperature is the optimum temperature specified by the polymer manufacturer. This is useful when a lower temperature expanding agent, like water is added to expand natural or man made polymers within short distances as in a nozzle and die head. The lower temperature substance may cause the temperature of the polymer to drop. The higher temperature during machine operation helps maintain or raise temperatures following addition of cooler expanding agent. Heating of elements 14 is controlled by a temperature control system 10 in conjunction with a first thermocouple 16 during idle and in conjunction with a second thermocouple 18 during machine operation.
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