Binding of gantry systems

Ive noticed that newer Fab@Homes tend to bind up more than their elder brethren. While making my lab's newest Fab@Home model 2, i think i came across the solution to the problem.

the Acrylic plates flex and can vary in thickness. This can lead to the system settling into different tensions and stresses based on these factors and the order of tightening of the screws. If the plate is in a bad configuration, it will cause the sleeve bearings to misalign ,and cause stiction and binding of the axis.

The solution seems to be changing the build order. By putting the shafts through the bearings on the bridge, carriage, and z table before screwing the plates together you lessen the stiction. With the carriage, you need to also put a tool on it before tightening all of the screws.