Press force (overmolding): XY Plot result

The Press force (overmolding): XY Plot result shows the force applied by the press during of the overmolding step of the analysis, displayed on an XY plot of force versus process time.

This result is generated from a Thermoplastics injection-compression overmolding analysis, when you select injection-compression for the overmolding step.

Using this result

For the compression phase of injection-compression molding, the press force is calculated by multiplying the pressure by the projected area of the compression surfaces (excluding the feed system) on the parting plane, at specific time instants.

If only press packing is applied, when the press force reaches the press force used, it will remain at that preset value (constant force).

Note: The number of time steps plotted on the XY graph is determined by the input specified for the Number of regular results in Filling phase and Number of regular results in Packing phase options.

Things to look for

The objective is for the thickness of the molded part to be the same as the specified design thickness. This occurs when the press displacement result is equal, or as close as possible, to the press open distance.

Note: Design thickness + press open distance (input) - press displacement (result) = final molded part thickness.

If the final molded part thickness is too much larger than the design thickness, try adjusting one or more of the following process settings and re-run:

• Increase the Press compression force so that the material is more compressed.
• Keep the injection location open after packing so that extra material is squeezed out.
• Reduce Velocity/pressure switchover by %volume so that less material is injected into the cavity.
• Increase the Fill time, to reduce the flow rate.
• Increase the Press speed so that the press closes sooner.
• Reduce the Press open distance.
• Reduce the Press waiting time so that the press closes sooner, before too much material is injected into the cavity.

An example of the relationship between the Injection-compression results and how to interpret them, is provided in the Press displacement result.