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Designing in multi-materials for 3D print

posted 12 October 2016 at 22:36:12

While huge advances have been made in the world of 3D printing in the last decade, it still has been difficult for non-programmers to create objects made of multi-materials, or mixtures of materials, due to a lack of user-friendly interfaces. This week, a brainy team from MIT's Computer Science and Artificial Intelligence Laboratory (CSAIL) unveiled 'Foundry', which is billed as a more intuitive system that allows you to custom-design a variety of 3D printed objects in multiple materials.  

Today’s multi-material 3D printers are mostly used for prototyping, because the materials currently used are not very functional. Designers typically create preliminary models, make rapid adjustments and then print them again.  
In contrast, Foundry acts as an interface to help create such objects. To use it, you first design your object in a traditional CAD package, such as SolidWorks. Once the file is exported, you can determine the object’s composition by creating an 'operator graph' that can include any of approximately 100 fine-tuned actions called 'operators'. Operators can subdivide, remap or assign materials. Some operators cleanly divide an object into two or more different materials, while others provide more of a gradual shift from one material to another.  

Foundry lets you mix and match any combination of materials and also assign specific properties to different parts of the object, combining operators together to make new ones. For example, if you want to make a cube that is both rigid and elastic, you would assign a 'rigid operator' to make one part rigid and an 'elastomer operator' to make the other part elastic. A third 'gradient operator' connects the two and introduces a gradual transition between materials.  

Users can also preview their design in real-time, rather than having to wait until the final steps in the printing process to see what it will look like. 'In traditional manufacturing, objects made of different materials are manufactured via separate processes and then assembled with an adhesive or another binding process,' says PhD Kiril Vidimce, one of the authors of a paper from CSAIL’s Computational Fabrication Group. 'Even existing multi-material 3D printers follow a similar workflow: parts are designed in traditional CAD systems one at a time and then the print software allows the user to assign a single material to each part.'  

In contrast, Foundry allows users to vary the material properties at a very fine resolution that, until now, hasn’t been possible.   'It’s like Photoshop for 3D materials, allowing you to design objects made of new composite materials that have the optimal mechanical, thermal and conductive properties that you need for a given task,' says Vidimce. 'You are only constrained by your creativity and your ideas on how to combine materials in novel ways.'  

To demonstrate, the team designed and fabricated a ping-pong paddle, skis with retro-reflective surfaces, a tricycle wheel, a helmet and even a bone that may, some day, be used for surgical planning. Redesigning multi-material objects in existing design tools takes experienced engineers and designers many days and some designs still prove unworkable. With Foundry, claim its inventors, you can create these designs in minutes.  

'3D printing is about more than just clicking a button and seeing the product,' says Vidimce. 'It’s about printing things that can’t currently be made with traditional manufacturing.' To test Foundry, the team tried the system on non-designers. They were given three different objects to reproduce: a teddy bear, a bone structure and an integrated 'tweel' (tyre and wheel). With just an hour's explanation, users could design the bone, tyre wheel, and teddy bear in an average of 56, 48 and 26 minutes, respectively.   In addition to the user study, the team also fabricated a custom wheel for a toddler's tricycle. The wheel had an improved structure to maximise lateral strength and a foam outer wheel for improved suspension.  

Using Foundry to exploit the full capabilities of the 3D printing platform could enable many practical applications in medicine and more, claims the MIT team. Surgeons could create high-quality replicas of objects, such as bones, to practice on, while dentists could develop more comfortable dentures and other products that would benefit from having both soft and rigid components.  

Vidimce’s ultimate dream is for Foundry to create a community of designers who can share new operators with each other, to expand the possibilities of what can be produced. He also hopes to integrate Foundry into the workflow of existing CAD systems. 'The user should be able to iterate on the material composition in a similar manner to how they iterate on the geometry of the part being designed,' says Vidimce. 'Integrating physics simulations to predict the behavior of the part will allow rapid iteration on the final design.'  

The paper’s co-authors include MIT professor Wojciech Matusik and students from his Computational Fabrication Group: PhD student Alexandre Kaspar and former graduate student Ye Wang. The paper will be presented later this week at the Association for Computing Machinery’s User Interface Software and Technology Symposium (UIST) in Tokyo. The research was supported by the National Science Foundation.  

Click on the YouTube link at the top of this blog to watch Foundry in action.
Images: © Kiril Vimidce/MITCSAIL