CoreXY

CoreXY is a printer motion design in which a closed belt system moves the print head in X and Y, while the build plate moves along the Z axis.

Why it matters

In a CoreXY printer, two motors work together on the belts, so the X and Y movements depend on each other. Prusa describes this as a specific belt design, with the print surface lifting to meet the extruder.

What moves on a Cartesian printer and on a CoreXY printerTwo top views. Cartesian: the print head moves left and right, and the bed slides front to back. CoreXY: the print head moves in both directions on belts, and the bed stays in place in the top view because it only moves up and down.CartesianCoreXYHead: left, rightBed: front, backHead: all four waysBed: up and down
Seen from above: on many Cartesian printers the bed slides back and forth under the head; on a CoreXY printer the head moves in X and Y on belts and the bed only moves up and down. From Polymaker's and Prusa's printer guides.

The main benefit is speed. Polymaker lists faster travel speeds and acceleration, higher precision from the belt system, and a design that is easier to enclose.

The bed is also lighter to move than on many Cartesian designs, where it slides back and forth. Prusa notes that the lighter axes mean faster prints without the artefacts fast Cartesian printing can show.

There are trade-offs. Polymaker lists a more complex belt and pulley system that needs careful calibration, and higher cost and maintenance.

An easier-to-enclose frame suits materials that need an enclosure. Fast printing doesn’t remove problems such as stringing or warping, which depend on temperature, material and settings.

When you compare printers, check whether the model is CoreXY or Cartesian, along with its build volume and enclosure options.

Sources