In an attempt to eliminate belt crossings, I've hit upon this variant of the CoreXY concept:
[attachment 89033 Scrappy-CoreXY-Layout.jpg]
Excuse my poor attempt at a drawing.
Solid pink - top "A" belt.
Solid black - top "B" belt
Dashed lines - moving carriages
The CoreXY belts are driven by co-located steppers (the circles with a "dot" in them) at the top left.
The Y axis (vertical) belts are tensioned on either side of the Y axis smooth rod.
The X axis (horizontal) belts are tensioned centered on the X axis smooth rods.
The left cap of the X axis is mounted on the Y axis smooth rod with a UU style bearing.
The right cap of the X axis rods is 'floating' - the 4 bearings are on a carriage that rests on a smooth rod, with no UU style bearing.
The bottom cap of the Y axis contains separate tension adjustment for each belt.
Since the A and B belts are isolated in Z, there is no 'crossing' of the belts.
Since the right X cap is floating, there is no "competing load" on two UU style bearings on the Y axis rods.
Sacrifices:
* Co-located stepper mounting is a bit of bear.
* The 'floating' right side of the X axis won't exert pressure as much on minor blobs as a UU bearing, so it could lead to 'blob mountains' - I'll need to test that
* If I don't get the tension just right, this assembly will probably torque out of calibration
Has anyone seen a similar CoreXY variant? If so, what can I learn from it before I spent more time on my variant?
[attachment 89033 Scrappy-CoreXY-Layout.jpg]
Excuse my poor attempt at a drawing.
Solid pink - top "A" belt.
Solid black - top "B" belt
Dashed lines - moving carriages
The CoreXY belts are driven by co-located steppers (the circles with a "dot" in them) at the top left.
The Y axis (vertical) belts are tensioned on either side of the Y axis smooth rod.
The X axis (horizontal) belts are tensioned centered on the X axis smooth rods.
The left cap of the X axis is mounted on the Y axis smooth rod with a UU style bearing.
The right cap of the X axis rods is 'floating' - the 4 bearings are on a carriage that rests on a smooth rod, with no UU style bearing.
The bottom cap of the Y axis contains separate tension adjustment for each belt.
Since the A and B belts are isolated in Z, there is no 'crossing' of the belts.
Since the right X cap is floating, there is no "competing load" on two UU style bearings on the Y axis rods.
Sacrifices:
* Co-located stepper mounting is a bit of bear.
* The 'floating' right side of the X axis won't exert pressure as much on minor blobs as a UU bearing, so it could lead to 'blob mountains' - I'll need to test that
* If I don't get the tension just right, this assembly will probably torque out of calibration
Has anyone seen a similar CoreXY variant? If so, what can I learn from it before I spent more time on my variant?