overlapping lines in a block exported to illustrator

[emme]

Hello, everyone!
I have an autocad block that I am trying to export to illustrator, transforming it first in pdf. How come the final result in illustrator is a vector with 4 overlapping lines for each line of my original design?
not being able to "clean" the work in illustrator because it would be complicated, almost impossible, does not there exist a procedure that avoids such an error of image generation?
I have already tried with _overkiller, but I can't.. .
I tried to export directly through dxf or dwg, but I even get omitted some parts of the image... who knows? !

 

[lattu]

bhe, or place the block or explain to us in detail how it is done because without information it is a little difficult to help

 

[PlannerRoad]

Is it a solid block?

 

[emme]

I modeled an ion column that I placed inside a system of Cartesian plans in order to repropose as exercise the method of monge of double orthogonal projections. . when I apply to the design the command asscav to place it in front assonometry, the work becomes a single block that, brought into an illustrator via pdf, turns into a load track of overlapping lines. . .