Pressure is the basic characteristic of die casting processing, and the filling flow and compaction of metal liquid are all accomplished under the action of pressure. The pressure is divided into dynamic pressure and pressurized Injection. The dynamic injection force is used to overcome all kinds of resistance and ensuring that the metal liquid reaches a certain speed when filling. The effect of the supercharged pressure force is to compress the die-casting parts and increase the density of the die casting, so as to make the shape of the die casting more clear. The pressure is through injection plunger to put pressure on the metal liquid.
1.2 Expanding mold force
In the processing of die-casting, under the action of pressure, the metal fluid fills the cavity with a certain pressure on the wall of the cavity and the parting surface, which is called the expanding force. The last phase of die casting processing, the supercharging pressure is through metal liquid to pass on die casting mould, at that time the expansion force is the largest. It is the most important parameters of the strength and rigidity for choosing die casting machine type and primary supporting plate.
In the processing of die-casting, the velocity is directly affected by the pressure, and it also plays an important role in the internal quality and surface contour definition. The velocity has two forms: shot velocity and ingate velocity.
1.4 Shot velocity
Shot velocity is also called plunger speed. It is the pressure in the chamber to push the velocity of the metal liquid, which is the speed of the plunger. The shoot velocity processing is variational. It can be divided into two stages: low speed and high speed. The speed regulating valve can be adjusted by the speed regulating valve of the die casting machine.
1.5 Ingate Velocity
Ingate velocity is linear velocity which is metal liquid passing ingate into cavity. High speed ingate velocity is using lower specific pressure to full fill with cavity instanly before metal liquid solidifies to make out a clear shape, surface finish die casting part and at the same time to inprove dynamic pressure of metal liquid. If ingate velocity is with too high speed and it will lead to a series of problems. Such as air hole, surface defect and increasing abrasion of die casting moulds and so on.