The CoreXY 3d printer design is very different than most common 3d printer motion systems that have dedicated stepper motor for each axis. The core-xy motion system is designed to minimize torque while moving the gantry and carriage.
The Advantages of the corexy system is the increased print speeds that can be achieved due to the light weight carriage. While 3d printing is a very slow process any kind of reduction in print time is much needed. In addition to faster print speeds the smooth motion that the core xy uses is also known to reduce artifacts commonly found in 3d printed objects.
The corexy kinematics mechanical arrangement includes a unique motor movement where
X or Y motor move together or opposite of each other to move the carriage from left to right or towards or away . If you were to move just one motor you would see the print head move diagonal.. If the two motors move opposite of each other the print head will move along the X-axis, If the two motors move in the same direction the carriage will move along the Y-axis.
CoreXY vs Cartesian
Most printers utilize Cartesian or plotter style motion where one or two motors will move the carriage from left to right or towards and away. This is the simplest approach in 3d printer motion. While the core xy setup is more complicated but a more efficient approach.
CoreXY Belt Path
The corexy 3d printer belt path has been explored in many mechanical arrangements. The main two corexy belt routing methods are belts crossed or not crossed. The main focus should be to keep the belt routing path parallel to the X and Y guide rails. There’s an excellent blog about corexy belt path by Mark Rehorst here.
CoreXY vs Hbot
Source: Shaqour, Bahaa. (2016). Developing an Additive Manufacturing Machine. 10.13140/RG.2.2.10190.77128.
A similar mechanical arrangement of the core-xy is the H-bot. The Hbot uses the same concept of carriage motion as the corexy but is much more simple and requires less math. In addition the hbot is harder to “get wrong.” The corexy belt path has it’s pros and cons. The corexy’s disadvantage is that it requires two belts on two separate planes. The coreXY balances the forces while moving the gantry or carriage to minimize “racking’ where the mechanical system is pulled out of square.