Shot sleeve wave dynamics in the slow phase of die casting injection

An analysis is carried out on the wave formed during the slow phase of die casting injection processes. Viscous effects are assumed to be negligible a nd the problem is treated two-dimensionally using finite amplitude wave the ory. Two commonly used types of plunger movements are considered, for which all the possible wave profiles are analyzed in depth as a function of the parameters which characterize the law of acceleration applied to the plunge r, the initial shot sleeve filling fraction, and the geometrical characteri stics of the problem. Different relationships between the relevant dimensio nless parameters of the system are proposed, which make it possible to opti mize the injection process, and so reduce the entrapment of air which leads to porosity. The validity of such relationships is analyzed in detail for different ranges of parameters. Some of the results obtained for the optimu m acceleration are compared with those of other authors and experimental me asurements. Finally, a law of plunger acceleration which would completely e liminate the air from the shot sleeve at the end of the slow phase of injec tion and minimizes the filling time is derived. [S0098-2202(00)02002-2].