Projected area

The projected area AS is the name given to the active surface of a casting including the gating system which is projected onto the parting plane of the permanent mold (e.g. a die casting mold).In the die casting process, the projected area (shown in Figure 1) is made up of:

The die opening force FS effective on the projected area, i.e. the force which would push the permanent mold open, is the product of the two factors of the projected area and specific casting pressure pG and is calculated according to Eq. 1 as follows:

Eq. 1:

As the available die locking force FZ of a die casting machine depends on the machine and is of a set size, this represents the upper limit of the range. For a casting, the projected area AS and the casting pressure pG can therefore be used to calculate the die opening force FS which can be compared with the die locking force FZ of the chosen die casting machine.

The size of the projected area therefore determines whether the casting in question can actually be cast using the intended machine at the chosen casting pressure. As shown in Figure 2, only the casting area projected on the mold parting plane, i.e. the projected area, is important and not the weight of the casting.

The relationship between the projected area and the casting pressure and the die locking force (without safety margin) is shown in Figure 3. As each die casting machine is only designed for a certain maximum die locking force, the maximum dimensions for the projected area are determined under consideration of the necessary die diameter and the runner and gate system.

  • Fig. 1: Projected area AS of a die casting and force on  the parting plane of a die casting mold
  • Fig. 2:  Three die castings with the same projected area but different casting weights
  • Fig. 3: Relationship between the projected area, the casting pressure and the die locking force (without safety margin)
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