4-tower delta

luca Massimiliano

good morning, is it possible to add a 4th tower to a delta printer, therefore an extra motor with RepRapFirmware for Duet 2 WiFi/Ethernet version 3.5.2?

T3P3Tony

@luca-Massimiliano is this for a 4th set of delta arms, or something different? if its for a 4th set of delta arms I think it would need an appropriate kinematics done, but importantly, why would you want to do this?

luca Massimiliano

@T3P3Tony I think that by increasing the stability and rigidity of the structure I can achieve greater precision, less vibrations and better print quality, as well as better weight distribution. Can you tell me how I can implement this kinematics?

T3P3Tony

@luca-Massimiliano I think that would make the system over constrained? Someone with more knowledge of mechanical systems would need to confirm that.

As this post is in the multi axis printing area though i will highlight that is you split one of the sets of parallel arms on 1 tower into two and control them independently, you get rotation as well as translation of the effector, see this cool video:
https://www.youtube.com/watch?v=3yUislC0aS0&ab_channel=OleksandrStepanenko

I don't expect that is what you want though?

For an overview of adding new Kinematics to RRF, see:
https://github.com/Duet3D/RepRapFirmware/wiki/Adding-New-Kinematics

luca Massimiliano

@T3P3Tony thanks for the video, really amazing. and thanks for the directions on the cinematic folder. bye

droftarts

@T3P3TonyThis one shows a delta with 6 degrees of freedom: https://youtu.be/3fbmguBgVPA

@luca-Massimiliano Do you mean more like this? https://www.thingiverse.com/thing:714915
I think they are generally called 'square deltas', but I only ever remember seeing one video on Youtube of someone who built one, and can't find it now.

There is a note in the Linear Delta guide about tower positions https://docs.duet3d.com/User_manual/Machine_configuration/Configuration_linear_delta#notes-on-configuration, ie in RRF you can position the 3 towers at any point around the circle, so you could build a square delta just with three towers, like the one above. But I don't think RRF supports the 4th tower in the delta kinematics. I don't know how difficult it would be to extend the delta kinematic to include a fourth tower; one for @dc42 .

Unfortunately, while the Hangprinter kinematics in RRF supports 4 'anchors', I don't think this could be adapted to use the fixed arms of a delta.

Ian

dc42

@droftarts @luca-Massimiliano RRF does support additional delta "towers" but not to add extra degrees of freedom to the effector, only for e.g. keeping an extruder drive at the correct height so that a shorter Bowden tube can be used between it and the hot end.

luca Massimiliano

@droftarts GRAZIE