Modify the files of CNC 3018. The original design is suitable for CNC 3018 PRO.
I moved the two parts containing the LM10UU bearings closer together, thus extending the size of the workbench to 30×20 centimeters.

The base itself is relatively flat, but I added the original "toothed structure" to it. These toothed components were originally embedded in the grooves of the aluminum bedplate, which allowed me to slightly raise the platform to prevent my set of threaded clamps from hitting the machine frame when tightening them.

These small protrusions can be flexibly arranged at any position between your workbench and the base as needed.

Be sure to keep the original bearings and use the same thread specifications for the central screw.

To ensure that the bearing and the central screw slide smoothly, I first assemble the entire set of components, and then use a heat gun to moderately heat and soften the parts that are stuck