CSL was founded in 2001 by Hod Lipson, a professor of mechanical and aerospace engineering and director of graduate studies in mechanical engineering. The Fab@home project was launched four years later. Alternatively known as rapid prototyping technology, Fab@home was conceived as a way to mainstream 3D printing by creating a global community of hobbyists and others who have accessed Fab@home’s instructions and kits to built personal 3D printers. A score of Cornell researchers are involved in Fab@home, though a virtual community of thousands has been created.
Industrial designers have used 3D printers to create prototype cars and prosthetic devices, typically from resins or starch, but mainstream applications-for example, fabricating a replacement part for a machine-are not practical with printers costing $40,000 or more. Making available low-cost printers that combine multiple ingredients to create cookies, turkey dinners and other foods, on the other hand, is generating mainstream excitement. Users load a recipe, or FabApp, into the machine, and the food is extruded and layered to create the desired shape and density. Grad student Jeff Lipton heads the FabApp project, under the direction of Dr. Lipson.
A graduate of the Israel Institute of Technology, Lipson holds BS and PhD degrees in mechanical engineering, with a focus on CAD and artificial intelligence in design. He previously was a visiting scholar at MIT, where some work on food printing also has been done. However, the Cornell project is exploring a wider range of foods and driving down costs for the syringe-based 3D printers that create them.
Lipson: Though the technology has been around for 20 years, 3D printers have been very expensive. In 2005, the lab’s Fab@home project made open-source blueprints available for building a 3D printer. People could either buy the parts, easily acquired for about $1,600, or buy a kit for $2,200.
FE: When did food become part of the project?
Lipson: Food printing began in 2007. Originally we printed objects and circuits, but when I talk to people about those applications, their eyes glaze over. Now, when I mention food, they light up. When my mother heard about it, she wanted to know if I could print lasagna.
A high school girl in Kentucky printed the first food. She used a heated syringe to get chocolate to flow and print line by line, layer by layer, in a three-dimensional shape she had programmed. That led to our FabApps project. The reaction has been an eye-opener. There is something very fundamental about working with food.
FE: What has been the biggest challenge?
Lipson: Learning to deal with the rheological properties of food. It has to be soft enough to be extruded through a syringe, yet solid enough to hold its shape afterward. Finding the right temperature balance for the food was tricky, as was printing in high resolution.
FE: How has food impacted the overall project?
Lipson: It’s been fascinating to see how this captivates people’s imagination immediately. We are on the cusp of change in the way change happens. It’s similar to the transition that occurred in computer technology. The mainframe dominated computing in the 1960s. Even then, IBM and Honeywell recognized the potential of home computing, but no one could figure out how to develop it until small companies started making PCs. Then gaming applications came along, and that created the initial market for home computing. Developments in simulation and sound technologies came about because researchers were focused on the growing community of gamers.
3D printers are following the same cycle. Would making toys, medical implants or something else popularize them? We put our printer out, not knowing how it would be used. It turns out that food is perfectly suited to this technology. Food is user friendly, everybody has some knowledge about it, and it is a very disarming application. FabApps could be to 3D printing what gaming was to home computing, creating initial interest and unleashing many people’s creative energy.
FE: How central is food printing to Fab@home’s work?
Lipson: Everything we’ve done with food has been a byproduct of other work we’ve done. Our funding comes from groups like the National Science Foundation and the Defense Department, and they have no interest in printing food. But 3D printing with food is what grabs people.
FE: Is there a connection between 3D printing and your work in artificial intelligence and robotics?
Lipson: Some researchers say any machine with intelligence and the ability to be mobile is a robot. The printer won’t be mobile, but it definitely has intelligence. Ultimately, you would want to tell the machine what food or object you want, and it would make it for you.
FE: Some of your work involves machines with self-awareness and the ability to self-simulate. Might that apply to food apps?
Lipson: That is a different story, but machines with self-diagnostics and self-correction ability are an area of interest. Taken to the extreme, it suggests machines with the intelligence to simulate an outcome before doing anything. It would be useful for any machine to learn from the thousands of details of its work: “If these ingredients are used, the food won’t hold together, or people won’t like the way it tastes.”
We’re experimenting with an evolutionary design process in which the computer breeds robots. It starts with a thousand robots of random shapes. Most are completely nonfunctional, but the computer takes the elements that do work and combines them over and over until you have a robot that does what you want it to do. Thousands of generations of design are involved, yet it takes the computer five minutes to do it.
FE: Besides food, what are you printing?
Lipson: Multi-material objects are the focus. Food fits in perfectly with this work, and it has such complex geometry.
Printing cookies was an interesting project. Cookie dough is easy to extrude, and we tried printing it with a vertical C, for Cornell. But it required multiple formulations before we could create a C that did not deform. Another interesting experiment involved turkey and celery. Neither of those is extrudable through a syringe or ink-jet nozzle, so we needed to use a binder.
FE: Have you involved the university’s food science department in the FabApps project?
Lipson: There have been a few e-mail exchanges, but there hasn’t been any formal contact, and that’s my fault. Some students from the Center for Hospitality Research are working with us, as is the French Culinary Institute in New York. David Arnold, the institute’s director of culinary technology, has advised on food safety issues and the addition of hydrocolloids and other binders to print foods that don’t deform.
Chefs are experimenting with the technology in their own restaurants. Some view this as a way to cut waste from current food production and distribution. As with any technology, if it isn’t explained, people aren’t sure if it’s a good thing. There are those who want to move away from technology in food, so 3D printing can be somewhat controversial.