What Happens when Cold Inserts Are Placed in a Mould and Encapsulated with Hot Polymer?
Inhomogeneous mould temperatures inevitably lead to inhomogeneous temperatures in the insert. Due to the interaction of insert and polymer melt, it can happen that the melt cools down quicker, leading to solidified or highly viscous layers in the polymer that have a direct influence on further filling.
Hence, the insert determines the position of the weld lines, the required pressure, the fiber orientation or scorch.
The animation shows the formation of weld lines in the part. The clipping mode shows the wall thickness of the part. The weld line melt in version 1 is much cooler than in version 2. This can lead to optic defects or even part failure as the melt is significantly cooler and travels a shorter distance than in version 2.
The applied adhesive agent is only able to react at a certain surface temperature of the insert. Adhesive agents require an exact temperature control: too low temperatures prevent their activation; too high temperatures lead to degradation. Only the exact thermal calculation of the heat flow leads to accurate results.
Insert and part are connected in the subsequent packing, cooling, and heating phase, e.g. they heat up or cool down together. The different thermal and mechanical properties of insert and polymer lead to stresses, warpage, and perhaps to unbalanced curing in the part that may even cause part failure (break) or result in insufficient part properties (damping, oscillation, etc.)
Based on physically/mathematically implemented parameters and using a methodically consequent approach, SIGMASOFT considers the complex thermal and rheological processes and allows to virtually optimize your part geometry, your inserts, and the whole production process in an early phase of development.
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