Mould clamping force

Note that if Pq is substituted back into the expression for P then the expression used earlier (Chapter 4) to calculate the mould clamping force is obtained. That is... 

Though its production, e.g. in an injection moulding machine, requires special tricks, the injection pressures and the mould clamping forces required are much lower than with a solid product. 

The two main parameters for machine size are, the maximum shot size that can be injected in a single forward movement of the screw, and the maximum mould clamping force / damp- The shot size is usually quoted in terms of the mass of polystyrene that can be injected. The clamping force, typically in the range from 100 kN to 100 MN, restricts the maximum projected area A of a moulding onto the mould parting plane (Fig. 5.24). A typical average melt pressure p in the mould is 20 MPa, and the condition... 

Moving the central nozzle away from the mould axis causes an asymmetrical mould structure, asymmetrical loading of the ejection system and an asymmetrical stress distribution in the injection machine columns. The effective mould clamping force is diminished. 

The next section will consider issues relating to the mould clamping force requirements. 

It is found in most cases, that flash (see Chapter 9 for a description) is not caused by inadequate mould clamping force or locking pressme, but by an insufficient rigidity of the mould in the areas concerned. 

Flowability Very good, as LSR systems have low viscosity Therefore, the injection pressure and mould clamping forces required are also very low... 

In order to remove the air blister even at faster initial injection speeds, the mould clamping force, which had previously been set very high (too high) was reduced until satisfactory ruiming was achieved again. This example shows that a mould clamping force which is not too high, and which is satisfactorily set,... 

Moreover, the equipment is looked after better the lower the mould clamping force, the lower the wear. 

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