What is your data source / what kind of object are we talking about ?
Usually voxel data needs to be translated to a polygons to be an object as in itself it is a 3d image and not a surface.
Using an implicit surface modeller with a threshold at the desired value should produce a closed surface that is printable.
You could render a point set/cloud from the voxel values (above threshold -> point, otherwise not)
Then you could use meshlab to generate a surface using marching cubes. Matlab also has plenty of functions for this.
If you have a low resolution version and need any help just post it here. I use custom software for implicit surfaces.
Edit :
I thought your nick was familiar ! You're the mandelbulb guy, right ?
(I occasionally drop by on fractalforums)
I guess you are after the mandel variants ? I myself had not much luck yet.
I did manage some rudimentary quat-julias :
https://www.shapeways.com/model/41578/hypercomplex_julia.html
and
https://www.shapeways.com/model/41945/hc_julia_invert.html
But for the mandelbrots, producing anything in high-res, resulted in non-manifold objects with polygons over the 500.000 limit.
Which would then need a lot of repairing.
I got some simple mandel-eggs from low-itercounts, but nothing worth printing yet.
But I didn't try the white formulas yet