Perfect optical properties transferred to micro applications
Micro injection-compression molding
Optical functions in particular are subject to ever greater miniaturization. A well-known example from our everyday lives is the integrated camera of every modern smartphone. This miniaturization is only made possible by high-precision micro-optics made of plastic. For micro-optics of high imaging quality, such as for demanding applications in measurement and medical technology, component stresses are often difficult to control. Internal stresses and molecular orientations in injection-molded plastic optics cause birefringence effects that lead to undesirable polarization and thus transmission effects. This problem can be eliminated, as in the injection molding of "large" components, by a superimposed injection-compression process. In a partially opened mold, a defined preform is generated within the cavity and then formed into the finished component by means of a compression molding process. Due to the uniform pressure distribution throughout the cavity, internal stresses and thus anisotropic optical properties are reduced to a minimum.
The technological basis for micro injection compression molding of the smallest optical components is the formicaPlast modular machine platform with plunger injection units, which was developed at KuZ for micro injection molding. A vertical machine design with electric drives meets the requirements of the process control necessary for this. Short cycle times and long flow paths are realized at low pressure levels.
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