@ThantiK @Whosa_whatsis How about if you added a 3rd rod to the design - free floating on the z axis - whose purpose was to add stability to the print head. The print head would travel along it as X changed, it would rise up and down with changes in Z, and it would stabilize Y, enabling the use of single rods or flat bars on simple hinges.
I would think this would add weight and friction, negating the advantages gained with the design. Unless it could be made light enough.
what weight the horizontal rod added I would think could be regained by the ability to use lighter components for the upper arms
I think this idea has merit. I run i3s and to remove a bar and add these would be ~ the same weight. I don’t have issues with stability of the head though…
@Brandon_Satterfield the stability issues come from being essentially a 2 armed delta. You would not have the other 4 arms to force the plane of the print head to be parallel to the plane of the bed.
You’d have to be careful that it was extremely low-friction and didn’t end up over- or under-constrained. Near the extremes, a horizontal move would result in a large vertical force on one end of the added rod, while the other end would be floating and would tend to droop and/or lag behind the other end. For best results, you’d have to move your Z axis to the center whenever you want to do a Z move.
@Whosa_whatsis That could definitely be an issue, but I think it could be minimized by the horizontal rod having a longer bearing surface on the vertical rods, and perhaps increasing the distance between the towers so that the horizontal travel stays in the middle 2/3rds of the horizontal rod. Dont know if it would work or not - just an idea that struck when I saw @ThantiK 's post.
I personally think the idea of making a third arm attach to one of the delta rails is a better one. It gets rid of the horizontal member, and helps maintain tram on the X end effector. I’m also digging whosa’s idea of it being in the X/Y plane, but you end up wasting so much space.