Additive manufacturing (AM) alias 3D printing translates computer-aided design (CAD) virtual 3D models into physical objects. By digital slicing of CAD, 3D scan, or tomography data, AM builds objects layer by layer without the need for molds or machining. Additive manufacturing differs from conventional manufacturing techniques in that structure are produced layer by layer by digitally slicing a CAD model, 3D scan or tomography data. Objects are built up layer by layer from the bottom up rather than requiring moulds or machining. Additive manufacturing processes are available for many different materials ranging from polymers to metals and ceramics.
The microstructure of additively manufactured materials can be very different due to the layer by layer process used to make them. For example, internal stresses can build up which need to be relieved by heat treatment and the composition and morphology of the powder precursors also has a significant impact on the quality of finished goods.
Asylum Cypher AFMs (Link to Cypher) has been used successfully in alternating contact mode to study the microstructure and mechanical properties of additively manufactured polymer/carbon nanotube based composites. AFM on microtomed surfaces reveals microstructural changes due to the additive manufacturing process and highlights strain relief processes which determine the structural integrity of the finished material.
Contaminant particles in precursor metal poweders can act as nuclei for strain, leading to cracking of the finished product. The powders are commonly screened for contaminants and their morphology is assessed using SEM/EDS based particle analysis (Link to AZtecFeature). We offer AZtecFeature classification schemes covering most common powders and contaminants, enabling rapid screening of test samples.
The microstructure of AM metallic objects can be different from the bulk metal or alloy, resulting in differing mechanical properties. Scanning electron microscopy based EBSD analysis can reveal internal strains and stresses along interfaces as well as the grain structure of the material and EDS can be used to identify and classify impurities and precipitates, similar to the use of non-metallic inclusion classification in traditionally manufactured steel and aluminium products.