RepRap: Blog

A couple of ways this parallelogram flexure can be used. Obviously, these are just lash-ups and the actual frames will be designed somewhat more competently with end bearings, anti-backlash, limit switches etc. They do at least demonstrate a much greater range of motion than the existing drivers.

The one above is more compact (50mm longer overall that the V0.03/4 driver), with shorter members. It'll drive the free end up and down. Nice, but somehow there is a motion stage that it needs to fit to somewhere. I like it though.

This one drives the free end horizontally, so is more likely to be out of the way of the final stage hardware. But it needs longer support structures, which will themselves flex, and is rather bulky to handle overall.

The exercise here is to get constrained linear motion and 2:1 linear reduction out of the driver, so that it can be driven by any old GRBL hardware. Either way I drive it, there is obviously one unconstrained direction. But the stages themselves are constrained, so I just have to make sure that movement in the unconstrained direction doesn't matter. Half of me wants to go "go linear and damn the reduction" but it'll be needed in later versions so I am persisting for now.

 

Notes to self: Mount points on the parallelogram centre need to be correctly spaced for 10mm centres. Driven end must not rub on support structure. Driven end for vertical driver needs to have a rest position above the drive screw, and the motor needs to be dropped by 10mm+.