Sustainable 3D Printing Methods Add to or Subtract from Existing Objects

Xiang ‘Anthony’ Cheng, along with colleagues at Carnegie Mellon University in Pittsburgh, Pennsylvania, has a really great idea intended to move us from 3D printing so many objects from scratch. The ideas for this design tool, Encore, evolved from some initial questions: “What if we can 3D print directly onto an existing object? What if we can just put an object onto the print bed and the printer can somehow figure out a way to print continually from this existing piece? What are the other possibilities that can extend an existing object without reprinting it?”

On his website, Cheng describes how this design tool works if you want to print an object attached to an already existing object. Take, for example, one of his real prints of a Teddy Bear onto a refrigerator magnet:

“Encore, our design tool, will rotate the Teddy bear so that the attaching point is facing upwards at a printable orientation. It also generates support material to hold this Teddy bear in place. So you can just print the support first, then tuck in the Teddy bear. But how does the print head know where to start? Turns out this information can also be computed as well know the dimension of the support and the Teddy bear. So all we need to do is, before you insert the Teddy bear, raise the print head using some generated G-code. And then use a little more G-code to direct it to start the print right above the back of the Teddy bear’s head.”

This makes sense, right? And it’s a really good idea that focuses on preserving existing objects through augmentation, kind of like recycling the old into something new. We first took a look at Encore back in August, and it’s becoming clearer now: the idea is catching on.

Another 3D printing designer, Stefanie Mueller and her colleagues at Pottsdam, Germany’s Hasso Plattner Institute, is focusing not just on adding parts to existing pieces, but milling redundant portions of an object away, printing an updated design to replace it. This is called “patching” and you can read more about it on Mueller’s website here.

Mueller and her colleagues explain what they created to achieve this new way to transform 3D printed objects:

“We built a system on top of a 3D printer that accomplishes this: Users mount the existing object into the 3D printer, then load both the original and the modified 3D model into our software, which in turn calculates how to patch the object. After identifying which parts to remove and what to add, our system locates the existing object in the printer using the system’s built-in 3D scanner. After calibrating the orientation, a mill first removes the outdated geometry, then a print head prints the new geometry in place.”

Now, that’s definitely a new way to view the role that 3D printing can play in new object iterations.

As the examples of both Cheng’s Encore, and Mueller’s notion of “patching” reveal, people are getting more creative about how to use 3D printing on already existing objects. Reinventing the wheel from scratch tests our patience, and it also is more wasteful of natural resources than working on existing objects. No doubt these ideas, and more like them motivated by similar sustainability concerns, will become more common.

In the meantime, if you have something around the house you want to alter, consider the Encore or patching methods to 3D printing to augment, or mill to transform, an already existing item. Discuss this story and technique in the Adding to Objects forum thread on 3DPB.com.