third prototype, good to show the concept,

3D Printing
,
1

third prototype, good to show the concept, but not working as smooth as wished
http://reprap.org/wiki/File:FoldaRap2_sci-try3_13.gif

2

Does friction between the MDF arms seem to be the problem?

3

even if it could be better the MDF seems usable for prototyping (or I may just add a washer), the friction appear when I add the top frame in the upper z-gliders, it still move but is a little hard to lift up (going down is ok if you don’t start from the max position)

4

I think you are dealing with trigonometry: a²+b²=c² With c = fix (mdf part), a = driving force, b = Z-lift
When Z is on the bottom the delta Z for delta a is at its maximum (and decreasing), need it’s most force.
Is it the purpose to use the lift of the Z-part to create layers? or just deploy the structure?

5

indeed it require a lot of force when starting from “z-min”, but as I want to use it as a Z-axis (yes to create layers! will need some firmware tuning to make it non-linear though), I will manage to put the Z-zero not at the minimum folded position : if you add a bed and all the electronic at the bottom, the scissors will be already ready to engage when starting from Z-zero (hopefully :slight_smile: )