Die Casting clamping force is the force applied to a mold by clamping unit of HPDC die casting machine. The clamping force must be grater their separating force.
Which applied by the injection of molten metal into the mold
The clamping fore > separating force
How to calculate the separating force (opening force)?
Opening force is the force acting on the cavity to make the die expand during the production of die casting part. The opening force can be calculated by the following formula:
F=PXA
F: opening force
P: specific injection pressure
A: Total projected area
What is Specific injection pressure?
Molten metal is ladled through the shot hole into the cold chamber and the shot plunger pushes the metal into the die. The pressure applied by plunger to push the metal into the die is specific injection pressure.
Injection pressure use for different type of casting:
- For standard casting =600 kg/cm2
- For technical casting =600−800 kg/cm2
- For pressure testing casting =800 kg/cm2
What is projected area?
The anticipated region is a two-dimensional zone estimation of a three-dimensional article by anticipating its shape on the plane.
Total projected area =casting projected area + slide projected area + runner projected area + overflow projected area
Example
- Casting projected areas =56000mm2
- Overflow + runner projected area =22400mm2 (40% of total casting projected area )
- Slide projected area=projected area must be selected in the plane that is normal to be direction of core travel x tanꬾ
Angle of wedge = angle of finger cam angle + 2degree
Force FY = F X Tan ꬾ
ꬾ = angle of wedge lock
Example:
- Slide core 1 projected area=area normal to direction of travel × tanꬾ
=5000× tan20 degree
=5000× 0.36
=1800 m2
- Slide core 2 projected area=4500×tan 20degree= 1620mm2 so,
Total projected area= 56000+22400+1800+1620mm2
=81820 mm2
What is separating force (Opening force)?
(For technical casting=600−800 kg/cm2)
(800 kg/cm2 =8kg/mm2)
Opening force = specific pressure ×total projected area
=8 kg/mm2 × 81820mm2
=654560 kg/mm2 (1 ton = 1000kg)
=654.56 T
Die clamping force
The clamping force must be grater then the separating force.
Locking force require =F×1.2
=654.56×1.2
=785.472 tons
We select the 900T machine
What is fill ratio, how it is important for selecting machine tonnage?
It is the percent of liquid metal vulnerable chamber contrasted with the absolute volume of the virus chamber. Another method for saying it would be the level of metal contrasted with the level of air exposed to the harsh elements chamber
For Example
50% full (of metal) = 50% air remaining
The level of fill is significant in light of the fact that it is utilized to ascertain the ideal moderate shot speed.
This can have a quality impact on the casting.
Fill ratio (30-40%) is good for automobile die casting component quality.
