By now, the most basic idea behind the way FFF/FDM 3D printers work is pretty well understood: a pretty small nozzle is moved around a static base, depositing material in a predetermined pattern based on design files. The method reduces waste through its additive, rather than subtractive, approach to materials use, and is especially useful for rapid prototyping.
But is it the best way?
Xerox, a company who has managed to turn their name into a synonym to the phrase ‘copy machine’, has also played a crucial role in the development of 2D printing technologies throughout the last couple of decades. For the most part they have stayed out of the 3D printing space, watching as other giants within the 2D printing space enter, such as HP.
This could quite well be about to change. A new patent, filed by Xerox Corporation, reimagines the process. The patent — filed under application #20150017271 on January 15th — is for the Digital 
Manufacturing System for Printing Three-Dimensional Objects on a Rotating Surface. Invented by Patricia J. Donaldson and Jeffrey J. Folkins for Xerox, who also posted a patent for printing such objects on a rotating core with co-inventor Naveen Chopra, this patent isn’t so much reinventing the wheel as simply adding a wheel. Both Donaldson and Folkins appear to have prodigious experience in patenting inventions, and so seem to be just the right team for the job.
This patent’s authors compare 3D printers available today to a standard home inkjet (2D) printer, partially to illustrate the idea of the moving printhead process, and partially, it seems, to indicate the outdated technology they consider it to be.
Despite additive manufacturing being inarguably less wasteful a technique than subtractive methods, Donaldson and Folkins argue that these “existing three-dimensional systems… use production techniques that are slow and generate significant waste.” The slow speeds are certainly an issue that many users familiar with 3D printing have noted, with small objects requiring hours upon hours of printing time. Any technique that might reduce printing time would surely be welcome, serving as the impetus for invention.
This particular invention focuses on improving the process of additive manufacturing by changing up the moving parts; rather than the printhead moving across the print bed, the print bed moves itself in a rotating fashion to accommodate the printhead.
This particular one focuses on improving the process of additive manufacturing by changing up the moving parts; rather than the printhead moving across the print bed, the print bed moves itself in a rotating fashion to accommodate the printhead.
The design focuses on two drivers to keep the system functioning. The first is used “to rotate the substrate past at least one printhead at a predetermined velocity,” while the second is intended “to 
move the position of the printhead perpendicular to the substrate to maintain a predetermined gap between the printhead and the layer of material most distant from the substrate.” That second driver also serves to adjust the resolution of the extruded material.
In addition to the drivers are controllers that operate the printhead. The controller adjusts the printhead’s operating pattern based on signals from its position encoder, which is then based on the movements of the substrate in regard to velocity and rotational position.
The patent goes on to describe two embodiments of their theoretical device, both of which feature slight variations on the same technique. In the first, a hollow member houses a printhead that extrudes its material onto an inner wall, while the driver rotates that wall around the printhead. In the second, a circular member houses the printhead while a driver rotates the member past the printhead and a second driver moves the printhead itself between printing positions.
Certainly rotational systems are not foreign to this industry, as several designs have been produced in the past which rely on the rotation of the print bed in order to speed the print process up. For instance we covered a company called Polar3D, whose founder we met at CES earlier this month. They were able to not only speed the print process up, but fit larger objects on a small printbed.
What do you think about this new patent? Would a design like this in fact speed up the additive manufacturing process? Let us know your thoughts on this design in the Rotating Print Bed Patent forum thread at 3DPB.com.
