Thixotropic injector with improved annular trap

摘要

By blocking an angular extent of an annular skimming trap used for semi-solid injection, a notable reduction in lenticular defects and porosity are observed. The blocking can be performed by a ring having dimensions to completely occlude a prior art annular skimming trap throughout the angular extent, and providing complete and/or partial flow across the ring throughout the rest of the angular extent. Preferably an outlet to the ring trap includes a chamfered edge and/or a deflector for encouraging flow of the contaminated semi-solid material into the trap.

主权项

1. An injector for injecting a thixotropic billet from a piston chamber into a mold, the injector comprising:
a piston chamber segment having a peripheral wall surrounding a center axis to define a piston chamber, the piston chamber terminated by an end wall; an entry channel in fluid communication with, and having a smaller diameter than, the piston chamber, the entry channel extending through the end wall; and, near the peripheral wall proximate the end wall, an outlet to a trap, the outlet extending only 10-70% of an angular extent around a center axis of the injector to block flow of the billet from the piston chamber into the trap at 90-30% of the angular extent, wherein the outlet is a channel extending from the piston chamber to the trap for selectively removing at least part of a skin around 10-70% of a periphery of the billet.