Has anyone found a cure for the whole frame flexing across the X-axis.

The frame, by the triangular design, is rigid on the y-axis; but on the x-axis
the design allows the same triangular design to flex in that x-axis direction.

Panels down the Y-axis slopes would help, but they would severely limit access
to the table.

www.thingiverse.com/thing:15606

This brace does a very good job of stiffening the frame in the plane you are referring to. After that to make a difference you should look at men delivery flavours of printer. The Mendel 90 for instance looks to have resolved the issue. I am building something even more solid as we speak. I ;o)

This thing is said to work well also:
[www.thingiverse.com]
Some people put a rectangle plate near the top on the ends too.
Don't forget that not all the end area of the frame is useful area since the X-axis takes up like the top third of the distance, only the height up the legs equal to your actual build height is useful and needs to be clear on the ends.
And ditto on the alternate REPRAP frame versions to suit your needs. The prusa mendel is the basic slimmed down build to get you started. Rigidity is only one dimension of the design matrix and trade-offs must be made, there is also parts count, cost, build time, availability of parts, heat tolerance etc...
Have fun.

Edited 1 time(s). Last edit at 10/14/2012 04:40PM by rrr7.

I (mostly) fixed the frame X-stiffness by bolting in a thick electronics mounting plate, like this: detail view