I’ve been doing pcb design around sensor coils for capacitive sensing. My engineering team has been playing with similar ideas around printing coils for other electro magnetic purposes. Motors are an obvious usecase. Good to see others doing similar stuff with printed circuit boards. It takes a way a lot of complexity and pcb processes have some pretty good precision these days.
I'm fairly ignorant about motor design, but my immediate thought was "isn't this going to exert pulling forces on the PCB traces?". Seems like that would limit how much torque your motor can exert? Which I guess isn't necessarily a problem for many applications.
The forces are pretty much shear forces in the plane of the PCB, which traces can handle reasonably well. Also, the amount of force per trace is very small - the motor only has significant torque because there are many traces per PCB multiplied by many PCBs.
I recall watching Carl Brugeja on YouTube some years ago making tiny motors using PCB for the coils, like this[1] for example. Like you say idea is hardly groundbreaking, but there's a lot of details to optimize as with any non-trivial engineering project.
[1]: https://www.youtube.com/watch?v=oa6sP-joAr8