independant dual gantry corexy

breed

Is it possible to run a dual gantry corexy setup on Reprap? I know that dual x carriages is possible, but two completely independant xy gantry and carriage?

jay_s_uk

@breed yes. and @deckingman runs one

deckingman

@jay_s_uk said in independant dual gantry corexy:

@breed yes. and @deckingman runs one

Saw my name being mentioned. For the record, I have 3 XY gantries so my machine is a CoreXYUVAB (plus Z).

Edit. Links to my blog and YouTube channel are in my sig.

breed

@jay_s_uk @deckingman
Why are the idex corexy machines I see all two x carriages on one gantry then? You are either giving up x travel by having two x carriages or giving up y travel with two gantrys, but with separate gantrys you aren't carrying the extra weight all the time. With crossed belts the routing wouldn't even be difficult.

breed

@jay_s_uk @deckingman
Deckingman I've been following your printer for years, it's astonishing.
Jay I'm also an anycubic predator guy.

deckingman

@breed said in independant dual gantry corexy:

@jay_s_uk @deckingman
Why are the idex corexy machines I see all two x carriages on one gantry then? You are either giving up x travel by having two x carriages or giving up y travel with two gantrys, but with separate gantrys you aren't carrying the extra weight all the time. With crossed belts the routing wouldn't even be difficult.

I guess it depends how one intends to use the independent gantries. In my case, I use a mixing hot end with multiple extruders. If those extruders were somehow arranged as direct drive, then the entire assembly would be extremely wide and one would lose a lot of XY travel. It would also be extremely heavy requiring large and substantial rails/belts/pulleys etc. An alternative would be to mount the extruders on the frame but for a 400mm square build area, the Bowden tubes would be around a metre long. Another alternative would be to use flex drive extruders such as the Zesty Nimble but these are not without their own problems. I elected to mount the extruders on a separate gantry above the the hot end. This reduces the space that the extruders would otherwise take up in X and Y while using very short Bowden tubes.
On the other hand, an IDEX is better suited where multiple hot ends are used.
Don't forget that slicers only generate XYZ(and E) moves. If you want to run truly independent axes, you need to find a way to generate the gcodes for those other axes. I use a little Python script which generates the UV and AB moves from the slicer generated XY moves and in my case, those other axes "follow" the XY gantry but within an allowable tolerance (due to the fact that the extruder gantry is not rigidly fixed to the hot end gantry). But if you want to run a hot end on each independent gantry to print multiple objects concurrently, then you'll need to generate some clever gcode to ensure that the gantries don't collide. A simpler alternative is to map the axes together so that they all react to the same XY gcode but offset in one or more directions. In that case, the axes are no longer truly independent.

dc42

One user took this further and built a machine with two independent X gantries, each of which carried two print heads in the same way as IDEX.

breed

@dc42 yeah I've seen that. Don't understand why you wouldn't just separate them x and y completely on a corexy. Dont make sense to me to carry around two x carriages for every y movement. Is it possible to assign xy for one extruder and UV for a second extruder? Dual color or dual material, I'm not thinking dual simultaneous printing of two different g codes.

Marcossf

You're surely interested in this.

4 printheads in a "coreXY"? hash kinematics. Now imagine doing a toolchange with each printhead

https://www.youtube.com/watch?v=tzf8903FvCs

Has anyone already dared?

o_lampe

@marcossf
my first approach will be 4 feltpens per tool = 16 pens in total. Toolchanging will be totally different of what's common today, but feltpens are different too. Maybe I add a single extruder and try to build a 'texture mapping' color printer later.