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ok so i noticed that corexy is based on the "H" principle, but i haven't seen any discussion of alternative arrangements whilst also keeping the corexy belt layout. i'd therefore like to ask people what they think of the above idea (ignoring that it's drawn by hand with "gimp"...)
to repeat and make absolutely clear: belt arrangement here is *exactly* as per corexy.
there are three linear bearings required per axis (pink for y, green for x), they are slightly offset in height, so that they go through the carriage (light orange). min/max/both endstops can be placed in the corners (statically) which is nice - i find it a royal pain to have to have the endstops moving on the carriage (or the x-ends).
in theory you could have doubled-up rods and bearings, either stacked vertically or horizontally, per axis, but this would be the minimum arrangement.
what is the motivation for considering this?
my primary motivation is that i see in the H design the weight of the carriage is exclusively placed onto the x axis, asymmetrically. i.e. when moving in the y direction, the carriage *and* the rails (and bearings) have to be moved, but when moving in the x direction, only the carriage has to move.
this bothers me. with the above arrangement, the weight distribution is balanced evenly between x and y. when a normal H-style corexy moves diagonally at 45 degrees, due to the "add/subtract" design of corexy, that's when the maximum load is placed on a single stepper: only one motor will be used to move both the carriage *and* the rails.
i feel then that this "plus" arrangement is a much more evenly-distributed load, and also, it avoids the whole "rotating" thing inherent in vertical rods "H" style corexy designs. and it also avoids the "whoops i have to make the rods really far apart in order to fit the hotend in between them" issue of the horizontal-rods variant of "H" corexy designs....
so, it would be a compact design, and have some advantages. what are the disadvantages (apart from needing a minimum of 6 linear bearings as opposed to four in an "H" style corexy).
ok so i noticed that corexy is based on the "H" principle, but i haven't seen any discussion of alternative arrangements whilst also keeping the corexy belt layout. i'd therefore like to ask people what they think of the above idea (ignoring that it's drawn by hand with "gimp"...)
to repeat and make absolutely clear: belt arrangement here is *exactly* as per corexy.
there are three linear bearings required per axis (pink for y, green for x), they are slightly offset in height, so that they go through the carriage (light orange). min/max/both endstops can be placed in the corners (statically) which is nice - i find it a royal pain to have to have the endstops moving on the carriage (or the x-ends).
in theory you could have doubled-up rods and bearings, either stacked vertically or horizontally, per axis, but this would be the minimum arrangement.
what is the motivation for considering this?
my primary motivation is that i see in the H design the weight of the carriage is exclusively placed onto the x axis, asymmetrically. i.e. when moving in the y direction, the carriage *and* the rails (and bearings) have to be moved, but when moving in the x direction, only the carriage has to move.
this bothers me. with the above arrangement, the weight distribution is balanced evenly between x and y. when a normal H-style corexy moves diagonally at 45 degrees, due to the "add/subtract" design of corexy, that's when the maximum load is placed on a single stepper: only one motor will be used to move both the carriage *and* the rails.
i feel then that this "plus" arrangement is a much more evenly-distributed load, and also, it avoids the whole "rotating" thing inherent in vertical rods "H" style corexy designs. and it also avoids the "whoops i have to make the rods really far apart in order to fit the hotend in between them" issue of the horizontal-rods variant of "H" corexy designs....
so, it would be a compact design, and have some advantages. what are the disadvantages (apart from needing a minimum of 6 linear bearings as opposed to four in an "H" style corexy).