Sep 3, 2018 | By Thomas
Silicone molding is an affordable production method that can allow you to make a series of identical objects for prototyping and functional testing. Until now, however, fabricating molds for casting complex objects required a lot of experience and also involved manual work, which made the process slow and expensive. Scientists at the Istituto di Scienza e Tecnologie dell'Informazione (ISTI-CNR) and the Institute of Science and Technology Austria (IST Austria) have developed a new tool for fabricating digital objects through reusable silicone molds. The tool automatically finds the best method to design the molds, and also delivers templates for so-called "metamolds": Rigid, 3D printed molds used to fabricate the optimized silicone molds.
The metamolds (red pieces far left and right) are used to fabricate the silicone molds (greenish and white shapes in the middle). Credit: Luigi Malomo
Silicone molding is simple and accurate and will forgive many mistakes. Extracting the object from the mold generally requires separating the mold pieces without getting them caught in overhanging parts of the object. A careful cut is required to open the mold. "Until now, silicone molding of complex shapes was a craft that needed years of experience and a skillful hand. You needed to know where to place the cuts ideally, and the work was done manually. Our new tool makes this method accessible for everyone," says Bernd Bickel, an Assistant Professor, heading the Computer Graphics and Digital Fabrication group at IST Austria.
With their new tool, the user just needs to upload the desired shape to the computer. The tool then calculates where the cuts need to be placed for an optimal result. This implies that the smallest possible number of mold pieces is utilized, and that the object can be safely removed from the mold once it is finished.
After that the computer automatically creates the 3D-printable templates of the metamold, a container that is used to create the ideal silicone mold pieces. The 3D printed metamolds are then filled with liquid silicone to produce the last silicone mold pieces, which are reusable and can be used to cast multiple replicas.
Scientists believe that this tool will be useful for small series production, such as in jewelry design or art. "When you are not producing millions of copies, this is the method of choice," says Thomas Alderighi from ISTI-CNR, the first author of the study.
As noted by Paolo Cignoni, research director at ISTI—CNR, one possible application is the production of a small number of replicas for museums that could be handled by visitors for a deeper experience of the exhibition.
The final silicone mold pieces can also be used to create replicas from a variety of different materials, including traditional ones like resin, but also unconventional ones like chocolate or ice.
Their method, which can lower the cost of silicone molding technique, is presented at this year's SIGGRAPH conference and published in the journal ACM Trans. Graph.
Posted in 3D Printing Application
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