A team of computer scientists from MIT’s Computer Science and Artificial Intelligence Lab (CSAIL) say that they have created a 3D printer that uses machine vision and 3D scanning to self-correct and directly embed components with up to ten materials at the same time. This, they explain, makes for a better, cheaper, more user-friendly printer.

Fig. 1 – MultiFab can print an unprecedented 10 different materials at once by using machine-vision and 3D-scanning techniques that save time, energy, and money. (Credit: Tom Buehler/CSAIL)
While the technology for 3D printing is still evolving, it is still not yet reliably able to product objects at a moderate cost. Companies have been working to tackle some of these challenges with “multi-material” 3D printers that can fabricate many different functional items. These printers, however, have traditionally been limited to up to three materials at a time, can cost as much as $250,000 each, and still require a fair amount of human intervention.

The CSAIL team says that their 3D printer can print an unprecedented 10 different materials at once by using 3Dscanning techniques that save time, energy, and money.

How It Works

Delivering resolution at 40 microns, the “MultiFab” system is the first 3D printer to use 3D-scanning techniques from machine vision, which offers two key advantages in accuracy and convenience over traditional 3D printing.

The MultiFab printer can self-calibrate and self-correct, which frees users from having to fine-tune the process themselves. For each layer of the design, the system’s feedback loop 3D scans and detects errors and then generates so-called “correction masks.” This approach allows the use of inexpensive hardware while ensuring print accuracy.

In addition, MultiFab allows users the ability to embed complex components, such as circuits and sensors, directly onto the body of an object. This means that the device can produce a finished product, moving parts and all, in one process.

Some of the technical challenges this printer has been able to resolve include the ability to print something complex without printing all individual pieces separately, and then assembling them by hand. With the MultiFab, they say, the user would simply put the components into the platform and the printer does the rest. Cameras automatically scan the components’ 3D geometries and use that information to print objects around them. For example, a user can place a cell phone into the printer, and program the system to print a case around it that is directly affixed onto the phone.

Other multi-material printers work via “extrusion” technologies, using nozzles that squirt out melted material that then hardens, to build an object layer-by-layer. Such techniques, while sufficient for certain uses, often lead to low-resolution finished items.

MultiFab, on the other hand, mixes microscopic droplets of photopolymers together that are then sent through inkjet printheads similar to those in office printers. The computationally intensive process, which involves crunching dozens of gigabytes of visual data, can be much more easily scaled to larger objects and multiple materials.

The MultiFab printer was built using low-cost, off-the-shelf components that cost about $7,000 total.

Future Work

The researchers have used MultiFab to print everything from smartphone cases to light-emitting diode lenses, and they envision an array of applications in microsensing, medical imaging, and telecommunications, among other things. They plan to also experiment with embedding motors and actuators that would make it possible to 3D print more advanced electronics, including robots.

For more information, visit http://news.mit.edu .

Medical Design Briefs Magazine

This article first appeared in the October, 2015 issue of Medical Design Briefs Magazine.

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