Using a 4th (Rotary) Axis

dc42

@littlehobbyshop said in Using a 4th (Rotary) Axis:

I'll have to be cautious with absolute and incremental movements in that case. Without a direction parameter there are always 2 ways to get to a position.

This is true. The firmware has the means to handle rotary axes differently (it's used on polar and some SCARA machines), but currently there is no command to declare that an axis is rotary.

3DPMicro

@littlehobbyshop please pass along your experience going forward. I occasionally add a 4th axis (currently just for indexing) to my Duet controlled micro mill. https://forum.duet3d.com/topic/11581/duet-controlled-micro-mill My CAM outputs 4th axis though I have yet to dedicate the time to explore simultaneous work. My current focus is an ATC for the machine but plan to start working again on the the "A" axis soon after that is complete

ScaraMan

@dc42 Hi David, I am trying to get in contact with you concerning SCARA.
I have posted a link on the forum , can you please have a look at it, I need your opinion.
Thank you

here is the link
https://forum.duet3d.com/topic/14114/scara-robot-want-to-know-if-duet-wifi-is-the-right-choice?_=1580465871679

Danal

I know you want an answer from dave... but... as @Phaedrux said in the other tread, Duet WiFi will definitely drive the scara geometry you show.

Here is how to configure it:

https://duet3d.dozuki.com/Wiki/ConfiguringRepRapFirmwareSCARAPrinter

tntjet

I’m kinda at a loss it may be old age or ignorance , how would one define the U axis (Rotary) to degrees instead of mm on a Cartesian CNC for M92 201 203 etc . Preferably to be a free axis with no limit switch .

@tntjet said in Using a 4th (Rotary) Axis:

, how would one define the U axis (Rotary) to degrees instead of mm on a

you sort of don't; i.e. the axis doesn't actually know about units - so just set the steps/mm to whatever steps you need to turn to move 1 degree instead of 1mm.

tntjet

Ok I see, that’s what I was missing , my axis has 600 steps per 360. 1.6666 per degree ?

@tntjet yes, if you have taken the microstepping into account, if not make sure to do that as well.

E.g. if its 600 full steps and you use 16x microstepping (with or without interpolation to 265) its 600 x 16 / 360 = 26.6666.

tntjet

Thank you so much @ bearer , you have made my evening.

is it possible to make this axis continuous in the M208?

@tntjet said in Using a 4th (Rotary) Axis:

is it possible to make this axis continuous in the M208?

ref https://forum.duet3d.com/topic/16788/u-axis-without-limit/12 (i.e. not yet faik)

tntjet

Legendary ! Thanks again.