Good news!
"... Engineers will have an easier time 3D printing objects out of multiple different materials with the release of an open-source tool, OpenVCAD, that can convert complex gradient designs into printer ready code for advanced engineering applications.
Designing and 3D printing gradients, where 2 materials gradually blend from one to another, is extremely difficult. ...
“This is the first multi-material, code-based design tool that is widely available. It allows for good complexity when printing objects, it’s accessible and it’s intuitive to write and design.”
Materials with continuous gradients, called ‘functionally graded materials’, can enhance the mechanical performance of materials, optimise weight distribution and eliminate sharp interfaces between materials where stress could concentrate in an object. ..."
From the abstract:
"This paper presents a novel gradient-informed slicing method for functionally graded additive manufacturing (FGM) that overcomes the limitations of conventional toolpath planning approaches, which struggle to produce truly continuous gradients.
By integrating multi-material gradients into the toolpath generation process, our method enables the fabrication of FGMs with complex gradients that vary seamlessly in any direction. We leverage OpenVCAD's implicit representation of geometry and material fields to directly extract iso-contours, enabling accurate, controlled gradient toolpaths.
Two novel strategies are introduced to integrate these gradients into the toolpath planning process.
The first strategy maintains traditional perimeter, skin, and infill structures subdivided by mixture ratios, with automated 'zippering' to mitigate stress concentrations.
The second strategy fills iso-contoured regions densely, printing directly against gradients to eliminate purging and reduce waste.
Both strategies accommodate gradually changing printing parameters, such as mixed filament ratios, toolhead switching, and variable nozzle temperatures for foaming materials.
This capability allows for controlled variation of composition, density, and other properties within a single build, expanding the design space for functionally graded parts. Experimental results demonstrate the fabrication of high-quality FGMs with complex, multi-axis gradients, highlighting the versatility of our method. We showcase the successful implementation of both strategies on a range of geometries and material combinations, demonstrating the potential of our approach to produce intricate and functional FGMs. This work provides a robust, open-source, and automated framework for designing and fabricating advanced FGMs, accelerating research in multi-material additive manufacturing."
Implicit Toolpath Generation for Functionally Graded Additive Manufacturing via Gradient-Informed Slicing (open access)
VCAD workflow: program → compile → export for printing or simulation.
