Injection pressure control - by sensing mould pressure and heater or obstructing material flow accordingly

摘要

The injection pressure in a mould for fluid synthetic resins is controlled by sensing the pressure within the mould and either controlling the temp. of the incoming material or its flow rate accordingly. Temp. may be controlled by heaters located around or projecting into the sprue and flow rate may be controlled by a plug which projects into the sprue. Such control produces highly uniform batches of articles and is simple compared with the prior cut. The pressure sensing means is pref. a plug slidable, in response to the pressure of the injecte material, in a bore leading into the mould cavity.