The simplest method of rendering raw material into solid body material is scanning the cross-sectional area line by line, and doing this layer by layer. However, material properties and conversion effects, namely thermal expansion and contraction, place restrictions on the quality achievable by this method. Thus, it is necessary to customize the beam’s or print head’s path to counter unwanted effects.
Generating such customization, although challenging due to the highly variable geometry between layers, can be broken down through a formulaic approach into basic steps. The Graphical Toolpath Editor allows for arranging these steps into toolpath definitions.
Toolpath calculation operates, part by part, on slice stacks. A slice stack is a list of layers, each one representing either an outer geometry or the actual laser lines (hatches) of a part. Stacks for the part itself, support and solid support are recognized individually. Slice Stacks are run through Slice Filters, whose output is again a Slice Stack. (A Slice Filter may take multiple Slice Stacks as input.) By chaining Filters, toolpaths are generated, each filter adding its own modification. Finally, a Post Processor receives the Stack and translates the generic toolpath information included into a machine-specific format while incorporating additional machine-specific information.