Zur Entstehung von Dimensionen und Maßabweichungen beim Laserstrahlschmelzen von Kunststoffen
The selective laser sintering of plastics enables the tool-free manufacturing of complex three-dimensional structures by incrementally joining individually laser exposed lines and layers in the powder. Starting with the production of prototypes, the additive manufacturing process has developed into an industrial manufacturing process for individualized parts.
For the technical and serial use of LS parts, a high degree of dimension and shape stability as well as reproducibility is required. For this reason, the basic linear and layerwise dimensional development in the selective laser melting of polyamide 12 using special exposure conform test specimens is investigated on a microscopic and macroscopic level. For this purpose, important influencing factors on the resulting part dimensions are analyzed in advance and subsequently kept constant.
Following the established theory, the incremental energy input results in a dimensional development dependent on the number of lines and layers. In particular for small structures, the individual portions contributing to the dimensional deviation could be identified and individual mutually compensating effects on the resulting dimensions were found. In addition, a possibility for quantifying the process-typical shape deviation is presented and the meniscus on the upper side of the component is evaluated as a function of the constituent increments and a theory for its origin is presented.