3D printing has evolved to address needs in many different sectors such as aerospace, medical and electronics. The high degree of customization in design and precision, enables this technology to adapt to very specific applications for e.g. as printing tissue substitutes in tissue engineering.3D printing is based on the principal of layered manufacturing. Each layer of the part’s cross section is deposited to create a full 3-D structure. Prior to printing, the CAD model for the part is sliced in what is called a slicing procedure. Here the parts cross-section is realized in each slice and tool path coordinates are generated. Presently, each slice of the model is planar, this means that the slices constitutes a stack of horizontal layers. It is well known that these horizontal layer slices result in the stair casing effect which effects the overall visual aesthetics of the resulting part. Moreover, the resulting fibre direction with respect to applied direction of loading can seriously affect the structural integrity of the critical part. When printing in planar layers/slices these effects can be ignored depending on the final application of the part. However, in specific applications they may carry critical importance. To deliver truly customized solution with utmost design freedom, 3-D printing needs more flexibility in the printing design process. While many of the printing parameters in current 3-D printing applications (slicer software) can be selected in the design process, the resulting print is still fabricated in planar layers.In this work, we have addressed this by presenting a procedure that can be adopted and further expanded for 3-D printing in curved layer. Here, the tool path coordinates are generated by slicing an STL model with non-planar surface. Slicing procedure is performed by utilizing parabolic surface function in implicit form. Using this approach ready to print Gcode files based on non-planar slicing surfaces can be generated. The methodology together with non-planar slicing algorithm presented were utilized to slice and fabricate various CAD models with curved layers. The visualized Gcode for the tool-path and some actual test results are also shared. Printing by means of customized slicing function can totally avoid stair stepping effect inherent to the available 3-D printing technology. It is shown that for specific applications, the proposed methodology resulted in parts with superior geometric characteristics.The main aim for this study is to explore the execution of custom slicing procedure for one particular slicing function. With the addition of more geometrically flexible and mathematically complex slicing functions, the possible applications are boundless.

Tool Path Generation for Free Form Surface Slicing In Additive Manufacturing/Fused Filament Fabrication

Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2021/volume/85543

ASME 2021 International Mechanical Engineering Congress and Exposition (IMECE2021)

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