Assistive design tools for additive manufacturing

​Design theories and methodologies are specifically developed to suit AM technologies. This research area focuses on optimising the design process efficiency. For non-experts, the ideation process, as well as the display and analysis of the designs conceptualised, require specific digital assistive tools. This post aims to scope these and summarise their uses.

Generally, design tools for AM can be categorised into four groups depending on their focus [1]:

• STL/AMF files repair and manipulation;
• Solid modelling;
• Support generation and slicing;
• Generation of internal structures and channels with variable densities;
  • Unpredictable geometries: FEA and topology optimisation,
  • Predictable geometries: multi-scale cellular structures generation.

​File repair and manipulation for non-experts

These applications are used to repair point cloud files, CT scans and generally STL/AMF files. Tools such as Geomagic Design [2] and Meshlab [3] remove noise, identify and fill data gaps before meshing out the surface of the design. They are mostly used with files generated via reverse engineering or issued from scanned or reconstructed medical images. 

​CAD design generation for non-experts

​Another type of assisting tool for non-experts is solid modelling CAD software, such as SolidThinking and Spaceclaim. These programs extract complex 3D models from 2D images or 2D drafts using automatic profile recognition or via manual interactive operations.  They can offer large libraries of complex features and user-friendly, jargon-free modelling operations (“pull” instead of extrusion). Less formal than more advanced and specialised CAD software (Solidworks, CATIA,…), they are well suited for brainstorming, conceptual demonstrations of complex designs, consumer products and art design. Arguably, the output geometries lack precision required for final engineering designs and the software is generally not capable of dealing with complex constraints and modelling information management. Yet, they can be readily utilised by user who do not need to learn about the mathematical constraints and rigorous geometric modelling mechanisms.

​Supporting structure and slicing

​These design tools are process oriented. They specialize in creating support structure (Magics,…) and generating machine-ready files for production. They consider DFM rules (to some extent) and specific AM manufacturing constraints. 

​Internal structures

​Internal channels and lattices are one of the star benefits of AM. Yet, it’s difficult to manipulate interior volumes to make full use of these. That’s where additional tools come in.
Depending on the predictability of internal structures, these design tools can be further divided into two sub-categories.
 
If internal volumes are predictable, that is if you have already decided on the shape and geometry of their shells and if you know where you want to add them, cellular structure featured software (i.e., Within Enhance) generates multi-scale features and lattices at acceptably high speed.
 
If these internal volumes are unpredictable, that is when you have to run programs to locate specifics areas based on structural or functional (or other) requirements, then topology optimisation software are best suited: HyperWorks is a good example.
 
Both Hypwerworks and WithinEnhance  are flexible enough to generate density variations in a single component

References:
[1]: Int J Adv Manuf Technol DOI 10.1007/s00170-015-6994-5 Additive manufacturing-enabled design theory and methodology: a critical review Sheng Yang1 & Yaoyao Fiona Zhao1 Received: 15 December 2014 /Accepted: 4 March 2015 # Springer-Verlag London 2015
[2]. 3DSYSTEMS (2015) Geomagic Design X. http://www.rapidform.com/products/xor/overview/
[3]. ISTI-CNR (2015) Meshlab. http://meshlab.sourceforge.net/.