@vicious1 would know better than me. He has a dining room table sized ZenXY. But I am not confident the ZenXY would work well with a 15lb load. Unless I am not understanding the spec.
Do you mean it has a 15lb mass on the middle? Or it has to push with 15lb of force? I’m assuming you mean the second. The ZenXY has almost zero force and the tool is an ounce or so of a magnet.
@mrehorst has a design for a sand table using servo motors. His machine draws at insane speeds. He would know more about the feasibility of that kind of load though.