MIT researchers, using off-the-shelf components, have built a 3D printer capable of building with 10 photopolymer materials at once.
And the school's Computer Science and Artificial Intelligence Laboratory (CSAIL) said the researchers were able to build the printer for less than $7,000. That compares to systems that print with just three materials at one time and can cost $250,000.
The MultiFab 3D printer works by mixing together microscopic droplets of photopolymers that are then extruded through inkjet printheads similar to those in office printers.
The printing process is computationally intensive and requires processing many gigabytes of visual data required to combine the various polymers, the researchers said.
The MultiFab 3D printer has so far only used ultraviolet-curable photopolymers -- meaning they're hardened by an LED lighting system.
"Additional materials such as co-polymers, hydrogels, and solvent-based materials can be adapted to be used within our platform," the researchers said in a paper on the printer.
MIT
Some of the objects printed by the MultiFab 3D machine, which illustrates the wide range of materials it can use.
The estimated cost of the printing materials is around $10 a pound, the researchers said.
Currently, the machine's printable materials include a rigid material (RIG), elastic material (ELA), high refractive index material (HR), low refractive index material (LR) and a support material (SPT).
Perhaps even more remarkable than the list of materials is the MultiFab 3D printer's ability to self-calibrate and self-correct during a print job. The printer has an integrated machine vision system that automatically readjusts the printer head if errors occur, rectifying the build before a problem ruins the object.
The MIT researchers said their 3D printer is made exclusively from low-cost, commercial off-the-shelf components. The use of a computer vision feedback loop simplifies the design and compensates in software for hardware deficiencies.
"Our system also pioneers inexpensive and safe LED curing (no other 3D printer we know of uses it) and a simple material feeding system. Our system adapts consumer printheads for polymer 3D printing," the MIT group wrote in a research paper. "This is achieved by optimizing the printhead waveform for each material and each droplet size separately."
Terry Wohlers, lead analyst with market research firm Wohlers Associates, said the MultiFab is a photopolymer material jetting system, somewhat similar to what is offered by Stratasys. Machines from Stratasys start at around $111,000.
Even if MIT's prototype was less expensive than industrial systems to create, that doesn't equate to what they may cost to produce commercially, Wohlers said.
"It's one thing for a researcher at a university to state the cost of parts that make up a machine, but it's something entirely different to commercialize a product and make it a sustainable business," Wohlers said. "When business people and investors get involved, major adjustments are usually made to the pricing."
Javier Ramos, a research engineer at CSAIL, said in a statement that the MultiFab printer "opens up new possibilities for manufacturing, giving researchers and hobbyists alike the power to create objects that have previously been difficult or even impossible to print."
Because of the wide range of materials available, the researchers used the MultiFab to build everything from smartphone cases to light-emitting diode lenses. The researchers said they can foresee an array of applications for the MultiFab 3D in consumer electronics, microsensing, medical imaging and telecommunications, among other things.
They also plan to try embedding motors and actuators in objects that would make it possible to 3-D print more advanced electronics, including robots.
The MiltiFab has high resolution, meaning the layers of material are extremely thin, creating a relatively smooth surface. The machine prints with "at least" 40 microns resolution or .04 millimeters.
By comparison, some of best consumer 3D printers today print at about .05 millimeters.
Along with industrial uses, the MIT researchers envisioned the printer being bought by service centers for customer-created designs.
"Picture someone who sells electric wine openers, but doesn't have $7,000 to buy a printer like this. In the future, they could walk into a FedEx with a design and print out batches of their finished product at a reasonable price," Ramos says. "For me, a practical use like that would be the ultimate dream."
