will it be fully 3d printed (no metal/carbon tubes)? I think the main problem with hobby robot arms is flex in the arm itself and backlash in the motors.
Low cost arms (eg. dobot) have "0.1mm repeatability" with no load but the moment you put a kg on the end effector it starts flexing.
Aside from bearings, motors, and possibly some fasteners, it will basically be entirely 3D printed.
I'm using printed spur geartrains that will have all kinds of backlash. In an effort to make something that is primarily printed, I'm throwing any hope of precision out the window. At least mechanical precision - we can use visual servoing to get more accuracy at the end effector.
But my hope is that the other benefits (low cost, easily changeable design, good speed and strength characteristics) will make it useful even with poor rigidity.
I imagine for example pulling things out of fixtures and moving them in to boxes.
There must be a good variety of tasks that can be done with an arm like this. I'm working to the strengths of 3D printing and not trying to fight what it isn't good for.
That said, I may reinforce the frame with a carbon fiber wrap if more stiffness is needed.
The goal is to have a low BOM cost AND low tooling cost so I want to avoid the need for any metalworking equipment.
Low cost arms (eg. dobot) have "0.1mm repeatability" with no load but the moment you put a kg on the end effector it starts flexing.