A new, sustainable take on the 3D printer reduces waste by eliminating the need for printed supports.

The additive-manufacturing technology, developed by researchers from USC Viterbi School of Engineering , features a movable platform of rising and falling pins. The small metal tubes prop up layers of a 3D-printed object as needed.

The work, led by Dr. Yong Chen, professor of industrial and systems engineering, and PhD student Yang Xu, has been published in Additive Manufacturing .

Printed stands often balance an object and ensure structural integrity as a printer creates an object layer by layer. The supports, however, must be manually removed after printing, leading to waste.

“When you’re 3D printing complex shapes, half of the time you are building the parts that you need; the other half of the time you’re building the supports," said Chen. "So with this system, we’re not building the supports. "

The research team’s new prototype runs all the metal supports from a single motor that moves a platform. The platform raises groups of metal pins at the same time.

Based on the product design, the program’s software tells the user where they need to add a series of metal tubes into the base of the platform. The position of these tubes then determine which pins will rise to defined heights to best support the 3D-printed product, while also creating the least amount of wastage from printed supports.

At the end of the process, the pins can be easily removed without damaging the object, and reset to the original position for the next printing job.

The graphical user interface (GUI) of the software system developed for the FFF 3D printer with reusable metal support.
The graphical user interface (GUI) of the software system developed for the FFF 3D printer with reusable metal support. (Image Credit: Chen)

The system may especially suit large-scale manufacturings in the automotive, aerospace, and yacht industries — businesses that are spending entire days building large-size parts with FDM printers, says Chen.

By reducing your support material, you reduce your time, according to the USC professor.

"If you can save half of that, your manufacturing time [for large-scale 3D printing] could be reduced to half a day," said Chen. "Using our approach could bring a lot of benefits for this type of 3-D printing.”

In a short Q&A with Tech Briefs below, Prof. Chen explains more about the movable approach to 3D printing, and how the rising and falling pins will impact designs.

Tech Briefs: How did this idea come about? (I heard the inspiration was from Legos?)

Prof. Yong Chen: The idea was actually inspired by 3D metal pin art. I have one in my office. It made me think about how we can use it for 3D printing. Later, we figured out a way of using pre-fabricated tubes with standard lengths with magnetics. The metal tubes with standard lengths can be pre-fabricated and given to users, similar to a set of Lego pieces.

Tech Briefs: Does the system automatically know which pins to raise, or does the user decide on the design phase? How is the information delivered on which pins to raise, and to what height? Is it via written instructions or some kind of automated process?

Prof. Yong Chen: Yes, we developed a software system for the reusable metal supports (see the image at the top of the page). It will optimize the layout of the input CAD models on the platform. Accordingly, based on the computation results, the software system will tell the user which tubes to pick from the tube box and insert onto which pin. The length of the selected tube will determine how high the related pin will rise up to.

Professor Yong Chen from USC
Dr. Chen, USC

Tech Briefs: Do the support-pin placements create limitations to what can be designed and built?

Prof. Yong Chen: I do not think it will create limitations on the design. The designer does not need to consider the pin design. Our software will optimize the layout and the related pin design, so the reusable pins will save the building time and support materials. The only difference for different placement is how much it can save (e.g., 30% vs. 25%). The worst scenario is no reusable metal pins are used, and all the supports are 3D-printed using the current approach (i.e., 0% saving).

Tech Briefs: Does the moveable platform have an array of pins, some of which can be raised? How many pins? What spacing? Does the size and spacing of the pins have to be designed anew for each product, especially if the products are different sizes? Different materials?

Prof. Yong Chen: The moveable platform in our prototype is 11 x 9: 99 pins. Each pin is 12.7-mm x 12.7-mm and can be raised up to different heights. They were fixed on size and spacing after the prototype system was built. They can be reused for different shapes and materials.

The platform size is 140 mm x 114 mm. We can make the platform size bigger by putting in more pins. We can also reduce the spacing between pins to have more pins for the same size. One good thing is the same hardware (i.e., one linear stage) can be used.

Tech Briefs: Are the metal rods separate pieces or are they attached to the assembly?

Prof. Yong Chen: The metal rods are separated from each other. They are attached to the three sheets through an inserted tube with a magnetic disc (on the bottom of the tube) or a magnetic ring (on the top of the tube).

Tech Briefs: How can you make sure that the pins don’t adhere to the product?

Prof. Yong Chen: The pin will attach to the 3D-printed supports or parts and will be detached from the metal rod when the 3D-printed part is taken out from the platform. The pin can be peeled away from the built part afterward (refer to 1:30 of this video .)

Tech Briefs: Do you still use printed supports as well?

Prof. Yong Chen: Yes, you will still need the 3D printed supports, but the amount of them can be reduced. Also, the 3D-printed supports can be much shorter, so the rigidity of the 3D-printed support can be improved.

What do you think? Share your questions and comments below.