<<< Back to information for moulders index >>>
Everyday information the injection moulder requires from Invotec Solutions.
The below article can be used for machine setters and machine operators of injection moulding machines.
Discover our full range of plasticising components or for the injection moulder.
View our other articles form our setter and operators guide for injection moulders. Taken from our moulders catalogue (Toolbox Edition)
How to calculate the specific injection pressure in injection moulding.
EXAMPLE 1
Given the following information, for a hydraulically actuated injection moulding machine, calculate the specific injection pressure used with a set hydraulic pressure of 118 bar.
- Diameter of Screw = 35 mm
- Diameter of Hydraulic Injection Cylinder Piston =130 mm
- Actual Hydraulic Injection Pressure used =118 bar
Hydraulic to specific Injection Pressure = Area of injection cylinder piston / Area of screw x hydraulic pressure
Specific Pressure = Area of cylinder piston / Area of screw x hydraulic pressure
Procedure: Insert information known
NB For all calculations convert mms to cms (divide by 10). The reason for this change is that 1 bar = 1 kg/cm2.
STEP 1 – Calculate the area of cylinder piston
Use formula you are most comfortable with.
Area of cylinder piston = π x D x D/2.2 or πR2
R = radius
D = diameter
π = Pi = constant (3.142)
Therefore: 3.142 x 13 x 13/4 or 3.142 x 6.5 x 6.5 = 132.75 cm2
STEP 2 – Calculate the area of the screw
Use formula you are most comfortable with.
Area of cylinder piston = π x D x D/2.2 or πR2
R = radius
D = diameter
π = Pi = constant (3.142)
Therefore: 3.142 x 3.5 x 3.5/4 or 3.142 x 1.75 x 1.75 = 9.62 cm2
STEP 3 – Calculate the speci!c injection pressure
Area of cylinder / Area of screw x Hydraulic pressure = Specific injection pressure
132.75 cm2 / 9.62 cm2 x 118 bar = specific injection pressure
Therefore: 1628 bar specific injection pressure
