2.1 Calculation of Clamping force for the Mold.

How to use the diagram :

1. Ascertain the projected injection surface. Ascertain the flow path/ wall thickness ratio.

2. On the diagram, draw a vertical line upwards from the value of the wall thickness on the horizontal axis until the line intersects the curve for the flow path/ wall thickness ratio : at the point of intersection, draw a line horizontally to the left and read off the value of the specific internal pressure (in bars).

3. The locking force in Mp is then calculated from :

   Specific internal pressure from the diagram X locking surface.

Example :

Projected injection surface : 200 cm2

Flow path about 90 mm

Wall thickness 1.25 mm

Resin of plastic :: PS, PE, PP

The diagram shows a spesific internal pressure of about 175 bars.

Clamping force = 200 x 175 = 35,000 kP = 350 kN = 35 Mp

The diagram is drawn up for the materials of good flow and for simple moldings. In the case of molding with numerous webs and changes in direction of material flow, and in the case of material with less good flow, the spesific internal pressure are higher (see also the factor to be applied for flow properties next page).