I've been thinking about 6-dof bots and the Sextupteron. The toolhead rigidity in Sextupteron concerns me, so I've been thinking about other geometries. What about a six-arm Simpson with a hexagonal toolhead? Actually, a hexagonal toolhead isn't ideal, it needs to have three long sides and three short sides to prevent twisting in the toolhead. This would still give a very wide work range, but it has the advantage that all six arms work together to bolster the rigidity, rather than having each axis's rigidity determined only by a pair of arms. Some might be concerned that Simpson's torsion springs will be a limiting factor on milling force (if used as a mill instead of a printer) , but remember that with six arms, three are pulling (driven) while three are pushing (un-driven). Simpson's apex even makes a natural toolhead switching area. https://reprap.org/forum/read.php?178,232805,232805#msg-232805 Sun, 15 Mar 2026 16:56:26 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?178,232805,236651#msg-236651 https://reprap.org/forum/read.php?178,232805,236651#msg-236651
Edit: 6DOF is for symmetry. Besides you can add a light duty gripper for assembly.]]> nicholas.seward Delta Machines Fri, 16 Aug 2013 09:23:29 -0400 https://reprap.org/forum/read.php?178,232805,236650#msg-236650 https://reprap.org/forum/read.php?178,232805,236650#msg-236650 Shawn.Walker Delta Machines Fri, 16 Aug 2013 09:22:27 -0400 https://reprap.org/forum/read.php?178,232805,236647#msg-236647 https://reprap.org/forum/read.php?178,232805,236647#msg-236647

I'm comfortable enough with the concept of 3-axis fdm that I could probably muddle through writing a slicer. I'm not sure where I'd start with 5DOF.]]> Shawn.Walker Delta Machines Fri, 16 Aug 2013 08:58:32 -0400 https://reprap.org/forum/read.php?178,232805,236312#msg-236312 https://reprap.org/forum/read.php?178,232805,236312#msg-236312 Thank you!]]> Buytaert Delta Machines Thu, 15 Aug 2013 19:36:56 -0400 https://reprap.org/forum/read.php?178,232805,236310#msg-236310 https://reprap.org/forum/read.php?178,232805,236310#msg-236310 nicholas.seward Delta Machines Thu, 15 Aug 2013 19:26:12 -0400 https://reprap.org/forum/read.php?178,232805,236308#msg-236308 https://reprap.org/forum/read.php?178,232805,236308#msg-236308 [youtu.be]
[youtu.be]
[3dprintingindustry.com]

Also, this is inspiring:
[youtu.be]]]> Buytaert Delta Machines Thu, 15 Aug 2013 19:19:20 -0400 https://reprap.org/forum/read.php?178,232805,233919#msg-233919 https://reprap.org/forum/read.php?178,232805,233919#msg-233919
Separate Note: A Stewart platform usually has a very limited range of motion. I guess I can get around some of that by having actuators that have a larger range of motion than what they usually use. Does that track?]]> nicholas.seward Delta Machines Thu, 08 Aug 2013 12:55:00 -0400 https://reprap.org/forum/read.php?178,232805,233868#msg-233868 https://reprap.org/forum/read.php?178,232805,233868#msg-233868 is fully constrained if you have a non-equilateral hexagon. In that respect, it has a lot in common with the Stewart Platform. In fact, you could use the Stewart Platform as a model for a Six-arm Simpson

There are two ways to constrain it: either make the base non-equilateral, or make the hub non-equilateral, or, even better, both. The closer you get to triangular on either the base or the hub, the more rigid the hub's position becomes. You can see that in the video I linked, they made both the hub and the base non-equilateral. That is, the arms are in pairs on the base, but they are in opposite pairs on the hub.]]> Annirak Delta Machines Thu, 08 Aug 2013 09:09:52 -0400 https://reprap.org/forum/read.php?178,232805,233685#msg-233685 https://reprap.org/forum/read.php?178,232805,233685#msg-233685 nicholas.seward Delta Machines Wed, 07 Aug 2013 19:06:24 -0400 https://reprap.org/forum/read.php?178,232805,232824#msg-232824 https://reprap.org/forum/read.php?178,232805,232824#msg-232824 [www.youtube.com]

Six-Arm Simpson would just be this inverted; the Annirak Drive instead of overhead arms.]]> Annirak Delta Machines Mon, 05 Aug 2013 04:55:42 -0400 https://reprap.org/forum/read.php?178,232805,232805#msg-232805 https://reprap.org/forum/read.php?178,232805,232805#msg-232805
What about a six-arm Simpson with a hexagonal toolhead? Actually, a hexagonal toolhead isn't ideal, it needs to have three long sides and three short sides to prevent twisting in the toolhead. This would still give a very wide work range, but it has the advantage that all six arms work together to bolster the rigidity, rather than having each axis's rigidity determined only by a pair of arms. Some might be concerned that Simpson's torsion springs will be a limiting factor on milling force (if used as a mill instead of a printer) , but remember that with six arms, three are pulling (driven) while three are pushing (un-driven).

Simpson's apex even makes a natural toolhead switching area.]]> Annirak Delta Machines Mon, 05 Aug 2013 03:31:22 -0400