Yes. I definitely need three arms per side to keep things parallel. Speed will certainly also be an issue with the moving build platform.
However, the design does have the advantage of only 3 motors for full X-Y-Z motion instead of 4 motors of a more traditional cartesian style printer. Instead of one motor/rail/belt for the X platform, two linear rails and 2 motors/lead screws in Z and one motor/belt/rail for Y, the hybrid would only use three motors/rails in total.
The other advantage is that with a much lighter Z axis, it can use belts or even rack and pinion drive on the Z axis instead of lead screws. A lighter Z-axis is less likely to fall down and go boom upon power loss.
With a hybrid design, there certainly are tradeoffs. The design would likely be as slow as a cartesian, but with thr rectangular build volume of a cartesian, and a few delta-style benefits (i.e. cheaper, lighter, simpler rail system and frame). But taller, and harder to program and level than a cartesian.
However, the design does have the advantage of only 3 motors for full X-Y-Z motion instead of 4 motors of a more traditional cartesian style printer. Instead of one motor/rail/belt for the X platform, two linear rails and 2 motors/lead screws in Z and one motor/belt/rail for Y, the hybrid would only use three motors/rails in total.
The other advantage is that with a much lighter Z axis, it can use belts or even rack and pinion drive on the Z axis instead of lead screws. A lighter Z-axis is less likely to fall down and go boom upon power loss.
With a hybrid design, there certainly are tradeoffs. The design would likely be as slow as a cartesian, but with thr rectangular build volume of a cartesian, and a few delta-style benefits (i.e. cheaper, lighter, simpler rail system and frame). But taller, and harder to program and level than a cartesian.